U.S. patent number RE31,993 [Application Number 06/515,546] was granted by the patent office on 1985-10-01 for cylinder gripping apparatus.
Invention is credited to William E. Wesch, Jr..
United States Patent |
RE31,993 |
Wesch, Jr. |
October 1, 1985 |
Cylinder gripping apparatus
Abstract
A cylinder gripping apparatus having a jaw, a body and a
floating interfacing assembly having a curved surface bearing
against an opposing surface or groove, the interfacing assembly
being operable to generate a proportional gripping force in
response to an axial force upon the cylinder to be gripped. The jaw
is not connected to the body. The interfacing assembly is operable
to permit a transverse displacement of the jaw.
Inventors: |
Wesch, Jr.; William E. (Lone
Star, TX) |
Family
ID: |
26725050 |
Appl.
No.: |
06/515,546 |
Filed: |
July 20, 1983 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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Reissue of: |
047471 |
Jun 11, 1979 |
04281535 |
Aug 4, 1981 |
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Current U.S.
Class: |
73/49.8; 138/90;
269/139; 277/558; 279/119; 73/49.5 |
Current CPC
Class: |
G01M
3/022 (20130101); G01N 3/12 (20130101); Y10T
279/1961 (20150115) |
Current International
Class: |
G01N
3/10 (20060101); G01M 3/02 (20060101); G01N
3/12 (20060101); G01M 003/28 (); B23B 031/16 () |
Field of
Search: |
;73/49.8,49.5,49.6,49.1
;138/90 ;279/110,118,119,121,123 ;269/139 ;277/205,26R,26A
;414/745 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Myracle; Jerry W.
Assistant Examiner: Roskos; Joseph W.
Attorney, Agent or Firm: Vaden, Eickenroht, Thompson &
Jamison
Claims
What is claimed is:
1. A cylinder gripping apparatus, comprising:
a jaw, said jaw having a friction surface adapted for gripping a
cylinder;
a body, said body being adapted to axially receive the cylinder,
said body having a front and a rear;
an interfacing assembly, said interfacing assembly being interposed
between said jaw and said body, said interfacing assembly being
adapted to urge said jaw into gripping engagement with the cylinder
when said jaw is urged generally rearwardly with respect to said
body, said interfacing assembly being adapted to provide a radial
counterforce in response to an axial force upon the cylinder, said
radial counterforce being proportional to said axial force, said
interfacing assembly having a curved surface on one end of said
interfacing assembly, said curved surface being cooperable with an
opposing face to permit a transverse displacement of said jaw from
an initial position to a displaced position.
2. The apparatus according to claim 1, wherein said opposing face
comprises a planar surface upon said jaw, said planar surface being
located upon a side of said jaw generally opposite to said friction
surface of said jaw.
3. The apparatus according to claim 1, wherein said opposing face
comprises a curved surface upon said jaw, said curved surface being
located upon a side of said jaw generally opposite to said friction
surface of said jaw.
4. The apparatus according to claim 1, wherein said opposing face
comprises a curved surface being adapted to receive said end of
said interfacing assembly having said curved surface.
5. The apparatus according to claim 1, wherein said opposing face
comprises a planar surface upon said body.
6. A cylinder gripping apparatus, comprising:
a jaw, said jaw having a friction surface adapted for gripping a
cylinder, said jaw having a first bearing groove;
a body, said body being adapted to axially receive the cylinder,
said body having a side wall, said side wall of said body having a
second bearing groove, said body having a front and a rear;
and,
an angularly disposed floating force translation lug, said lug
being engageable in said first and second bearing grooves, said lug
being adapted to operatively associate said jaw with said body,
said lug being adapted to urge said jaw into gripping engagement
with the cylinder when said jaw is urged generally rearwardly with
respect to said body, said lug being adapted to permit said jaw to
disengage the cylinder when said jaw is urged generally forwardly
with respect to said body.
7. The apparatus to claim 6, further comprising:
a first stay connected to said jaw, said first stay being adapted
to cover at least a portion of a cross sectional area of said first
bearing groove in said jaw, said first stay being adapted to
laterally retain said lugs within said first bearing groove while
leaving said lugs free to rotatively pivot within said first
bearing groove; and
a second stay connected to said side wall of said body, said second
stay being adapted to cover at least a portion of a cross sectional
area of said second bearing surface in said side wall, said second
stay being adapted to laterally retain said lugs within said second
bearing groove while leaving said lugs free to rotatively pivot
within said second bearing groove.
8. The apparatus according to claim 7, further comprising:
a resilient member disposed against said body, said resilient
member being interposed between said body and said jaw, said
resilient member being adapted to urge said jaw into engagement
with the cylinder.
9. The apparatus according to claim 8, further comprising:
actuating means connected to said lug for rotationally pivoting
said lug whereby said jaw is urged generally forwardly permitting
said jaw to disengage the cylinder; and,
an elastic member connected between said side wall of said body and
said jaw, said elastic member being adapted to urge said jaw
radially outward, said elastic member being adapted to urge said
lug into operative engagement with said first and second bearing
grooves.
10. The apparatus according to claim 9, wherein:
said first bearing groove comprises a first arcuate bearing surface
and further comprises a sloped forward surface, said forward
surface being adapted to permit said lug to rotate in a first sense
with respect to said jaw;
said second bearing groove comprises a second arcuate bearing
surface and further comprises a sloped rearward surface, said
rearward surface being adapted to permit said lug to rotate in a
first sense with respect to said sidewall of said body;
said lug having a first arcuate end and a second arcuate end, said
first arcuate end being adapted to substantially continguously
engage said first arcuate bearing surface of said first bearing
groove, said second arcuate end being adapted to substantially
contiguously engage said second arcuate bearing surface of said
second bearing groove, said lug being rotatably engageable against
said first and second arcuate bearing surfaces.
11. A hydrostatic testing apparatus for capping an open end of a
pipe comprising:
a jaw, said jaw having a first bearing groove, said jaw having a
friction surface adapted for gripping the pipe;
a body, said body being adapted to axially receive a pipe, said
body having a second bearing groove; and,
a force translation lug, said lug being unconnected to said body
and said jaw, said lug being disposable against said body and
against said jaw, said lug being adapted to rotatively engage
within said first and second bearing grooves, said lug being
operable to urge said friction surface of said jaw against an
outside surface of the pipe when said lug is rotated in a first
sense with respect to said body.
12. The apparatus according to claim 11, said body having an
interior zone, further comprising:
a purge valve connected to said body; and,
a passageway to place said purge valve in fluid communication with
the interior zone of said body.
13. The apparatus according to claim 11, further comprising:
a seal axially positioned within said body and adpated to form a
hydraulic seal between said body and the pipe to be capped, said
seal having a first lip disposable against the inner surface of
said body, the seal having a second lip connected to said first lip
and adapted to displace toward an outer surface of the pipe to be
capped.
14. A cylinder gripping apparatus, comprising:
a body, said body being adapted to axially receive a cylinder, said
body having a side wall, said side wall having an inclined inner
surface;
a jaw, said jaw having a friction surface adapted to grip the
cylinder;
a plurality of generally cylindrical rollers, said rollers being
unconnected to said jaw and said body, said rollers being
interposed between said jaw and said body, said rollers being
operable to facilitate the movement of said jaw relative to said
body along said inclined inner surface, said inclined inner surface
being adapted to urge said jaw into engagement with an outer
surface of the cylinder when said jaw is urged rearwardly with
respect to said body.
15. The apparatus according to claim 14, further comprising:
a plurality of channels formed traversely along said inclined inner
surface, said channels being adapted to receive said rollers, said
channels being generally cylindrically shaped in substantial
correspondence with the shape of said rollers.
16. The apparatus according to claim 14, further comprising:
a plurality of channels formed transversely along said jaw upon a
surface of said jaw generally opposite said friction surface, said
channels being adapted to receive said rollers, said channels being
generally cylindrically shaped in substantial correspondence with
the shape of said rollers.
17. The apparatus according to claim 15 or 16, further
comprising:
a resilient member disposed against said body, said resilient
member being adapted to urge said jaw into engagement with the
cylinder;
actuating means pivotally connected to said body for urging said
jaw generally forwardly with respect to said body; and,
an elastic member connected between said body and said jaw, said
elastic member being adapted to urge said jaw radially outwardly
toward said body into operative engagement with said rollers, said
elastic member being operable to maintain said rollers within said
channels.
18. A cylinder gripping apparatus, comprising:
a body, said body being adapted to axially receive a cylinder;
a cam arm pivotally attached to said body, said cam arm having a
generally arcuate cam surface; and,
a jaw, said jaw having a friction surface adapted for gripping the
cylinder, said jaw having a groove in a surface generally opposite
to said friction surface, said groove being adapted to receive said
cam arm, said cam arm being operable to urge said jaw into
engagement with an outer surface of the cylinder when said cam arm
is rotated with respect to said body.
19. The apparatus according to claim 18, further comprising:
a plurality of elastic members, connected between said body and
said jaw, said elastic members being adapted to urge said jaw
radially outward toward said body, said elastic members being
operable to urge said jaw into operative engagement with said cam
arm;
a forward alignment lip connected to the forward edge of said jaw;
and,
a rear alignment lip connected to the rear edge of said jaw.
20. A cylinder gripping apparatus, comprising:
a jaw, said jaw having a friction surface adapted for gripping a
cylinder, said jaw being adapted to dispose against a force
translation lug;
a body, said body being adapted to axially receive the cylinder,
said body having a side wall, said side wall of said body being
adapted to dispose against a force translation lug, said body
having a front and a rear; and,
an angularly disposed force translation lug, said lug having at
least one generally spherical end, said lug being interposed
between said body and said jaw, said lug being adapted to urge said
jaw into gripping engagement with the cylinder when said jaw is
urged generally rearwardly with respect to said body, said
spherical end of said lug being adapted to engage a generally
corresponding spherical groove, said spherical end and said
spherical groove being operable to permit said jaw to engage the
cylinder in generally corresponding alignment with the
cylinder.
21. The apparatus according to claim 20, wherein:
said spherical groove is located upon said side wall of said body;
and
said force translation lug is pivotally connected to said jaw.
22. The apparatus according to claim 20, wherein:
said spherical groove is located upon said jaw; and wherein said
force translation lug is pivotally connected to said side wall of
said body.
23. The apparatus according to claim 20, wherein:
said force translation lug further comprises a second generally
spherical end remote from said first spherical end; and,
said spherical groove is located upon said side wall of said
body;
and further comprising:
a second spherical groove generally corresponding to said second
spherical end, said second spherical groove being located upon said
jaw, said ends of said force translation lug being adapted to
engage said grooves, said force translation lug being operable to
permit radial, axial and transverse movement of said jaw with
respect to said body.
24. A platform jacking apparatus, comprising:
a body, said body being connectable to a platform, said body having
a guide sleeve, said body being adapted to axially receive a
platform leg,
a first set of jaws, said jaws being adapted to grip the platform
leg, said jaws being in operative association with said body, said
jaws being adapted to provide a first radial counterforce in
response to an axial force upon the platform leg, said first radial
counterforce being proportional to said axial force,
a jaw housing, said jaw housing being adapted to axially receive
the platform leg, said jaw housing being adapted to coaxially fit
within said guide sleeve of said body, said jaw housing being
adapted to reciprocally slide within said guide sleeve,
a second set of jaws, said jaws being adapted to grip the platform
leg, said jaws being in operative association with said jaw
housing, said jaws being adapted to provide a second radial
counterforce in response to said axial force, said second radial
counterforce being proportional to said axial force,
actuation means connected to said body and disposed against said
jaw housing for reciprocally moving said jaw housing within said
guide sleeve, said actuation means being operable to extend and
retract said jaw housing within said guide sleeve;
said first jaws being mutually cooperable with said second jaws and
said actuation means to grip the platform leg when said second jaws
are disengaged from the platform leg and said jaw housing is being
retracted by said actuation means; and,
said second jaws and said actuation means being mutually cooperable
with said first jaws to grip the platform leg when said first jaws
are disengaged from the platform leg and said jaw housing is being
extended by said actuation means, said actuation means, said second
jaws, said jaw housing, and said body being operable to raise the
platform when said jaw housing is extended by said actuation
means.
25. The apparatus according to claim 24, further comprising:
a first releaser, said first releaser being connected to said body,
said first releaser being in operative association with said first
jaws, said first releaser being operable to disengage said first
jaws from the platform leg to permit said actuation means to extend
said jaw housing and raise the platform;
a second releaser, said second releaser being connected to said jaw
housing, said second releaser being in operative association with
said second jaws, said second releaser being operable to disengage
said second jaws from the platform leg to permit said actuation
means to retract said jaw housing.
26. A member gripping apparatus for gripping a member having a
predetermined cross-sectional shape, comprising:
a jaw, said jaw having a friction surface adapted for gripping a
member, said friction surface generally conforming to the shape of
the member to be gripped;
a body, said body being adapted to axially receive the member, said
body having a front and a rear;
an interfacing assembly, said interfacing assembly being interposed
between said jaw and said body, said interfacing assembly being
adapted to urge said jaw into gripping engagement with the member
when said jaw is urged generally rearwardly with respect to said
body, said interfacing assembly being adapted to provide a radial
counterforce in response to an axial force upon the member, said
radial counterforce being proportional to said axial force, said
interfacing assembly having a curved surface of one end of said
interfacing assembly, said curved surface being cooperable with an
opposing face to permit a transverse displacement of said jaw from
an initial position to a displaced position.
27. The apparatus according to claim 26, wherein said opposing face
comprises a planar surface upon said jaw, said planar surface being
located upon a side of said jaw generally opposing to said friction
surface of said jaw.
28. The apparatus according to claim 26, wherein said opposing face
comprises a curved surface upon said jaw, said curved surface being
located upon a side of said jaw generally opposite to said friction
surface of said jaw.
29. The apparatus according to claim 26, wherein said opposing face
comprises a curved surface being adapted to receive said end of
said interfacing assembly having said curved surface.
30. The apparatus according to claim 26, whererin said opposing
face comprises a planar surface upon said body.
31. A member gripping apparatus comprising:
a jaw, said jaw having a friction surface adapted for gripping a
member, said jaw having a first bearing groove;
a body, said body being adapted to axially receive the member, said
body having a side wall, said side wall of said body having a
second bearing groove, said body having a front and a rear;
and,
an angularly disposed floating force translation lug, said lug
being engageable in said first and second bearing grooves, said lug
being adapted to operatively associate said jaw with said body,
said lug being adapted to urge said jaw into gripping engagement
with the member when said jaw is urged generally rearwardly with
respect to said body, said lug being adapted to permit said jaw to
disengage the member when said jaw is urged generally forwardly
with respect to said body.
32. The apparatus according to claim 31, further comprising:
a first stay connected to said jaw, said first stay being adapted
to cover at least a portion of a cross sectional area of said first
bearing groove in said jaw, said first stay being adapted to
laterally retain said lugs within said first bearing groove while
leaving said lugs free to rotatively pivot within said first
bearing groove; and,
a second stay connected to said side wall of said body, said second
stay being adapted to cover at least a portion of a cross sectional
area of said second bearing surface in said side wall, said second
stay being adapted to laterally retain said lugs within said second
bearing groove while leaving said lugs free to rotatively pivot
within said second bearing groove.
33. The apparatus according to claim 32, further comprising:
a resilient member disposed against said body, said resilient
member being interposed between said body and said jaw, and
resilient member being adapted to urge said jaw into engagement
with the member.
34. The apparatus according to claim 33, further comprising:
actuating means connected to said lug for rotationally pivoting
said lug whereby said jaw is urged generally forwardly permitting
said jaw to disengage the member; and,
an elastic member connected between said side wall of said body and
said jaw, said elastic member being adapted to urge said jaw
radially outwardly, said elastic member being adapted to urge said
lug into operative engagement with said first and second bearing
grooves.
35. The apparatus according to claim 34, wherein:
said first bearing groove comprises a first actuate bearing surface
and further comprises a sloped forward surface, said forward
surface being adapted to permit said lug to rotate in a first sense
with respect to said jaw;
said second bearing groove comprises a second arcuate bearing
surface and further comprises a sloped rearward surface, said
rearward surface being adapted to permit said lug to rotate in a
first sense with respect to said sidewall of said body; and,
said lug having a first arcuate end and a second arcuate end, said
first arcuate end being adapted to substantially engage said first
arcuate bearing surface of said first bearing groove, said second
arcuate end being adapted to substantially contiguously engage said
second arcuate bearing surface of said second bearing groove, said
lug being rotatably engageable against said first and second
arcuate bearing surfaces.
36. A member gripping apparatus for gripping a member having a
predetermined cross-sectional shape, comprising:
a body, said body being adapted to axially receive a member, said
body having a side wall, said side wall having an inclined inner
surface;
a jaw, said jaw having a friction surface adapted to grip the
member, said friction surface generally conforming to the shape of
an outer surface of the member to be gripped;
a plurality of generally cylindrical rollers, said rollers being
unconnected to said jaw and said body, said rollers being
interposed between said jaw and said body, said rollers being
operable to facilitate the movement of said jaw relative to said
body along said inclined inner surface, said inclined inner surface
being adapted to urge said jaw into engagement with the outer
surface of the member when said jaw is urged rearwardly with
respect to said body.
37. The apparatus according to claim 36, further comprising:
a plurality of channels formed traversely along said inclined inner
surface, said channels being adapted to receive said rollers, said
channels being generally cylindrically shaped in substantial
correspondence with the shape of said rollers.
38. The apparatus according to claim 36, further comprising:
a plurality of channels formed transversely along said jaw upon a
surface of said jaw generally opposite said friction surface, said
channels being adapted to receive said rollers, said channels being
generally cylindrically shaped in substantial correspondence with
the shape of said rollers.
39. The apparatus according to claim 37 or claim 38, further
comprising:
a resilient member disposed against said body, said resilient
member being adapted to urge said jaw into engagement with the
member to be gripped;
actuating means pivotally connected to said body for urging said
jaw generally forwardly with respect to said body; and,
an elastic member connected between said body and said jaw, said
elastic member being adapted to urge said jaw radially outwardly
toward said body into operative engagement with said rollers, said
elastic member being operable to maintain said rollers within said
channels.
40. A bar gripping apparatus for gripping a bar having a
predetermined cross-sectional shape, comprising:
a body, said body being adapted to axially receive a bar;
a cam arm pivotally attached to said body, said cam arm having a
generally arcuate cam surface; and,
a jaw, said jaw having a friction surface adapted for gripping the
bar, said friction surface being adapted to conform to the shape of
an outer surface of the bar, said jaw having a groove in a surface
generally opposite to said friction surface, said groove being
adapted to receive said cam arm, said cam arm being operable to
urge said jaw into engagement with the outer surface of the bar
when said cam arm is rotated with respect to said body.
41. The apparatus according to claim 40, further comprising:
a plurality of elastic members, connected between said body and
said jaw, said elastic members being adapted to urge said jaw
radially outward toward said body, said elastic members being
operable to urge said jaw into operative engagement with said cam
arm;
a forward alignment lip connected to the forward edge of said jaw;
and,
a rear alignment lip connected to the rear edge of said jaw.
42. A member gripping apparatus, comprising:
a jaw, said jaw having a friction surface adapted for gripping a
member, said jaw being adapted to dispose against a force
translation lug;
a body, said body being adapted to axially receive the member, said
body having a side wall, said side wall of said body being adapted
to dispose against a force translation lug, said body having a
front and a rear; and,
an angularly disposed force translation lug, said lug having at
least one generally spherical end, said lug being interposed
between said body and said jaw, said lug being adapted to said jaw
into gripping engagement with the member when said jaw is urged
generally rearwardly with respect to said body, said spherical end
of said lug being adapted to engage a generally corresponding
spherical groove, said spherical end and said spherical groove
being operable to permit said jaw to engage the member in generally
corresponding alignment with the member.
43. The apparatus according to claim 42, wherein:
said spherical groove is located upon said side wall of said body;
and,
said force translation lug is pivotally connected to said jaw.
44. The apparatus according to claim 42, wherein:
said spherical groove is located upon said jaw; and,
wherein said force translation lug is pivotally connected to said
side wall of said body.
45. The apparatus according to claim 42, wherein:
said force translation lug further comprises a second generally
spherical end remote from said first spherical end; and,
said spherical groove is located upon said side wall of said
body;
and further comprising:
a second spherical groove generally corresponding to said second
spherical end, said second spherical groove being located upon said
jaw, said ends of said force translation lug being adapted to
engage said grooves, said force translation lug being operable to
permit radial, axial and transverse movement of said jaw with
respect to said body. .Iadd.
46. A member gripping apparatus for gripping a cylinder, pipe or
solid bar having a predetermined cross sectional shape,
comprising:
a jaw, said jaw having a friction surface adapted for gripping a
member;
a body, said body being adapted to axially receive the member, said
body having a front and rear;
an interfacing assembly, said interfacing assembly being interposed
between said jaw and said body, said interfacing assembly being
adapted to urge said jaw into gripping engagement with the member
when said jaw is urged generally transverse with respect to said
body, said interfacing assembly being adapted to provide a radial
counterforce in response to a rotational force about the
longitudinal axis of the member, said radial counterforce being
proportional to said rotational force, said interfacing assembly
adapted to move relative with said jaw and said body to permit
transverse displacement of said jaw with respect to said body
between an initial position and a displaced position said radial
counterforce on the member created by said interfacing assembly and
the contact area of said jaw friction surface being predetermined
whereby said radial counterforce is less than the yield strength of
the member..Iaddend. .Iadd.
47. A member gripping apparatus for a cylinder, pipe or solid bar
with a predetermined cross sectional shape, comprising:
a jaw, said jaw having a friction surface for gripping the member,
said jaw having a first bearing groove generally opposite said
friction surface;
a body, said body having a side wall, said side wall of said body
having a second bearing groove, said body having a front and a
rear; and
an angularly disposed floating force translation lug being
engageable in said first and second bearing grooves, said lug being
adapted to operatively associate said jaw with said body, said lug
being adapted to urge said jaw transversely into gripping
engagement with the member when said body is rotated about its
longitudinal axis in a first direction, said lug being adapted to
permit said jaw to disengage the member when said body is rotated
in a second direction..Iaddend. .Iadd.
48. The apparatus of claim 47, further comprising:
a first stay connected to said jaw, said first stay being adapted
to cover at least a portion of a cross sectional area of said first
bearing groove in said jaw, said first stay being adapted to
laterally retain said lugs within said first bearing groove while
leaving said lugs free to rotatively pivot within said first
bearing groove; and
a second stay connected to said side wall of said body, said second
stay being adapted to cover at least a portion of a cross sectional
area of said second bearing surface in said side wall, said second
stay being adapted to laterally retain said lugs within said second
bearing groove while leaving said lugs free to rotatively pivot
within said second bearing groove..Iaddend. .Iadd.49. The apparatus
according to claim 47, wherein said first bearing groove in said
jaw is spherical, cooperating with a spherical end on said lug, the
opposite end of said force
translation lug is pivotally attached to said body..Iaddend.
.Iadd.50. The apparatus according to claim 47, wherein the radial
counterforce created by said force translation lug and the contact
area of the jaw friction surface are predetermined to allow radial
counterforce on the member without exceeding the members yield
strength..Iaddend. .Iadd.51. A member gripping apparatus for
gripping a cylinder, pipe or solid bar having a predetermined
cross-sectional shape, comprising:
a jaw, said jaw having a friction surface adapted for gripping the
member;
a body, said body being adapted to axially receive the member, said
body having a front and a rear; and
an interfacing assembly, said interfacing assembly being interposed
between said jaw and said body, said interfacing assembly being
adapted to urge said jaw into engagement with the member and to
provide a radial counterforce between said body and the member in
response to a rotational force on said body about the longitudinal
axis of the member, said interfacing assembly being adapted to move
relative with respect to said jaw between an initial and a
displaced position in gripping engagement with the member, said
radial counterforce created by said interfacing assembly and the
contact area of said jaw friction surface on the member being
predetermined whereby said radial counterforce is less than the
yield strength of the member..Iaddend. .Iadd.52. A member gripping
apparatus for gripping a cylinder, pipe or solid bar having a
predetermined cross sectional shape, comprising:
a jaw, said jaw having a friction surface adapted for gripping the
member;
a body, said body being adapted to axially receive the member, said
body having a first bearing means generally opposite said jaw, said
body further having a front and a rear; and
an interfacing assembly interposed between said jaw and said body
and having a second bearing means generally opposite said body,
said interfacing assembly including an angularly disposed force
translation device being engaged with said first and second bearing
means and adapted to operatively associate said interfacing
assembly and said body, said force translation device being adapted
to provide a radial counterforce between said body and said
interfacing assembly in response to a rotational force on said body
about the rotational axis of the member, said radial counterforce
being proportional to said rotational force and said radial
counterforce urging said jaw from an initial position to a
displaced position in gripping engagement with the member..Iaddend.
.Iadd.53. The apparatus according to claims 46, 51 or 52, wherein
said jaw is pivotedly connected to said interfacing
assembly..Iaddend. .Iadd.54. The apparatus of claim 53 wherein said
pivotal connection between said jaw and said interfacing assembly
is positioned in a predetermined location whereby said radial
counterforce on the member is balanced over said jaw friction
surface contact area with the member..Iaddend. .Iadd.55. A member
gripping apparatus for gripping a cylinder, pipe or solid bar
having a predetermined cross sectional shape, comprising;
a jaw, said jaw having a friction surface adapted for gripping the
member, said jaw having a first bearing means generally opposite
said friction surface;
a body, said body being adapted to axially receive the member, said
body having a second bearing means, and said body further having a
front and a rear; and
an angularly disposed force translation device engaged with said
first and scond bearing means and adapted to operatively associate
said jaw with said body, whereby said jaw is moveable between an
initial position and a displaced position in gripping engagement
with the member, said force translation device being adapted to
provide a radial counterforce on said jaw in response to a
rotational force on said body in a first direction about is
longitudinal axis, said radial counterforce being proportional to
said rotational force and urging said jaw into said displaced
position, said force translation device further being adapted to
enable said jaw to disengage the member and return to said initial
position in response to a rotational force on said body in a second
direction about its longitudinal
axis. .Iaddend. .Iadd.56. The apparatus according to claims 47 or
53 wherein said jaw is pivotedly connected to said force
translation lug..Iaddend. .Iadd.57. The apparatus according to
claim 56 wherein said pivotal connection between said jaw and said
force translation lug is positioned in a predetermined location
whereby said radial counterforce on the member is balanced over
said jaw friction surface contact area with the member..Iaddend.
.Iadd.58. The apparatus of claims 52 or 55, wherein said radial
counterforce applied to the member through said jaw friction
surface contact area does not exceed the yield strength of the
member..Iaddend. .Iadd.59. The apparatus of claims 52 or 55,
wherein said angularly disposed force translation device is adapted
to assume a predetermined angle of less than 45.degree. when said
jaw is in said displaced position, said angle being measured
between a first line through the longitudinal axis of the member
and an end of said force translation device opposite said body, and
a second line through a centerline between said first and second
bearing means..Iaddend. .Iadd.60. The apparatus of claim 59,
wherein said angle is between 10.degree. and 40.degree...Iaddend.
.Iadd.61. The apparatus of claim 59, wherein said angle is
20.degree...Iaddend. .Iadd.62. The apparatus of claims 52 or 53,
wherein at least one end of said force translation device is
spherical and said bearing means in engagement with said end of
said force translation device is a spherical groove adapted to
receive said end of said force translation device..Iaddend.
.Iadd.63. The apparatus of claims 52 or 55, wherein at least one of
said first and second bearing means is a pivot and an end of said
force translation device is rotatably connected to said
pivot..Iaddend. .Iadd.64. The apparatus of claims 52 or 55, wherein
at least one of said first and second bearing means comprises a
hinge and an end of said force translation device is rotatably
connected to said hinge..Iaddend. .Iadd.65. A member gripping
apparatus for gripping a cylinder, pipe or solid bar having a
predetermined cross sectional shape, comprising;
two or more jaws, each of said jaws having a friction surface
adapted for gripping the member, said jaws being concentrically
disposed with respect to the member;
a body, said body being adapted to axially receive the member and
said body having a front and a rear; and
two or more interfacing assemblies, each interfacing assembly being
interposed between said body and one of said jaws, and adapted to
operatively associate said jaws with said body, said jaws being
simultaneously displaceable between an initial position and a
displaced position in gripping engagement with the member, each of
said interfacing assemblies adapted to provide a radial
counterforce between said interfacing assemblies and said body in
response to a rotational force on said body, said radial
counterforce being proportional to said rotational force and said
radial counterforce urging each of said jaws into said displaced
position, said interfacing assemblies each including means for
urging said jaws into said initial position in the absence of a
rotational force about the member, said radial counterforce created
by said interfacing assemblies and the contact area of said jaw
friction surfaces on the member being predetermined wherein the
total radial counterforce exerted on the member is less than the
yield strength of the
member..Iaddend. .Iadd.66. A member gripping apparatus for gripping
a cylinder, pipe or solid bar having a predetermined cross
sectional shape, comprising;
two or more jaws, each of said jaws having a friction surface
adpated for gripping the member, said jaws being concentrically
disposed with respect to the member;
a body, said body being adapted to axially receiving the member and
said body having a front and a rear; and
two or more interfacing assemblies, each interfacing assembly being
interposed between said body and one of said jaws, and adapted to
operatively associate said jaws with said body, said jaws being
simultaneously displaceable between an initial position and a
displaced position in gripping engagement with the member, each of
said interfacing assemblies being adapted to provide a radial
counterforce between said interfacing assemblies and said body in
response to a rotational force on said body in a first direction
about its longitudinal axis, said radial counterforce being
proportional to said rotational force and said radial counterforce
urging each of said jaws into said displaced position, said
interfacing assemblies adapted to urge said jaws into said initial
position in response to a rotational force on said body in a second
direction about the longitudinal axis, said radial counterforce
created by said interfacing assemblies and the contact area of said
jaw friction surfaces on the member being predetermined wherein the
total radial counterforce exerted on the member is less than the
yield strength on the
member..Iaddend. .Iadd.67. The apparatus according to claims 65 or
66 wherein each of said jaws is pivotedly connected to one of said
interfacing assemblies..Iaddend. .Iadd.68. The apparatus according
to claim 67 wherein each of said pivotal connections between said
jaws and said interfacing assemblies are each positioned in a
predetermined location whereby said radial counterforce on the
member is balanced over said jaw friction surface contact areas
with the member..Iaddend. .Iadd.69. The apparatus of claims 65 or
66, further comprising one or more resilient members, each of said
members having one end attached to said body and another end
attached to one of said jaws whereby said jaws are urged into said
initial position..Iaddend. .Iadd.70. The apparatus of claims 46,
47, 51, 52, 55, 65 or 66, wherein said jaw friction surface is case
hardened..Iaddend. .Iadd.71. The apparatus of claim 53, wherein
said pivotal connection between said jaw and said interfacing
assembly comprises a hinge..Iaddend. .Iadd.72. The apparatus
according to claim 53, wherein said pivotal connection between said
jaw and said interfacing assembly comprises a spherical projection
on one of said jaw or said interfacing assembly, said spherical
projection engaging a similarly shaped spherical groove adapted for
receiving the spherical end in the
other of said jaw and said interfacing assembly..Iaddend. .Iadd.73.
The apparatus according to claims 46, 47, 51, 52, 55, 65, or 66,
wherein said friction surface of said jaw is releasably mounted on
said jaw whereby said jaw friction surface may be periodically
removed and replaced by a new friction surface..Iaddend. .Iadd.74.
The apparatus according to claims 46, 47, 51, 52, 55, 65 or 66,
further comprising retaining means provided to maintain the
apparatus in operational integrity..Iaddend.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
This application discloses subject matter related to U.S. Pat.
.[.application Ser. No. 037,140.]. .Iadd.No. 4,276,771 issued July
7, 1981.Iaddend., entitled "Hydrostatic Testing Apparatus",
.[.filed May 8, 1979,.]. having the same applicant, the disclosure
of which is incorporated herein by reference. This application also
discloses subject matter related to U.S. Pat. No. 4,077,250, issued
to the same inventor on Mar. 7, 1981, entitled "Pipe Closure
Apparatus", the specification of which is incorporated herein by
reference.
BACKGROUND OF THE INVENTION
This invention relates generally to an apparatus for gripping a
cylinder, pipe or tube. More particularly, this invention concerns
an apparatus having a plurality of jaws adapted for gripping a
cylinder, pipe or tube. The jaws are in operative association with
a body such that the radial gripping counterforce exerted by the
jaws upon the cylinder, pipe or tube is proportional to an axial
force upon the cylinder tending to urge the cylinder in an axial
direction with respect to the body. If the cylinder, pipe or tube
attempts to move axially with respect to the body, an interfacing
assembly urges the jaws into gripping engagement with the
cylinder.
In a hydrostatic testing apparatus, it is necessary to grip a pipe
or tube to be hydrostatically tested with sufficient force to
sealingly engage the apparatus upon the pipe. It is necessary that
the hydrostatic testing apparatus grip the pipe with sufficient
force to reduce or minimize the danger of the pipe slipping out of
the testing apparatus.
In the past, it has been common to grip a pipe or cylinder with
hydraulic rams and threaded devices to slips which apply an outside
force to hold a hydrostatic testing device or cap onto the pipe.
Such devices must be tightened to the pipe under substantially zero
internal pressure conditions because the slips must be firmly
engaged before the pipe can be pressurized. Tightening during
pressurization of the pipe is impractical and dangerous. During
zero pressure conditions there is no internal fluid pressure to
offset the clamping pressure or gripping force. Thus, such devices
must necessarily stress the outer wall of the pipe while there is
little or no internal pressure to offset the pipe gripping force.
If the initial gripping force is inadequate, the hydrostatic
testing cap will slip off during internal pressurization of the
pipe. If the initial gripping force is excessive, the pipe may be
deformed or weakened. For pressure testing, the jaws or slips of
such devices must be initially tightened to a holding force
sufficient to withstand test pressure before the pipe is
pressurized.
U.S. Pat. No. 4,077,250, granted to applicant herein, discloses a
pipe closure apparatus having gripper means connected to a spline
or rib by means of a rotatable link attached to a mounting pin.
This patent failed to disclose gripper means which are unconnected
to a spline or rib, but which are interfaced with the spline or rib
in a manner adapted to provide a radial counterforce which is
proportional to the fluid pressure in the pipe.
The earlier patent teaches the use of a single rotatable link
joining a gripper to a rib. A single link introduces stability
problems and may create undesirable stresses upon the diameter of a
pipe and the rib. Moreover, the earlier patent fails to address the
unexpected uneven distribution of the load forces upon the pipe
achieved by the gripper means disclosed in that patent where the
gripper means is not permitted to move generally parallel to the
axis of the pipe, or to move transversely with respect to the axis
of the pipe.
In prior art jacking systems for offshore oil drilling platforms,
it has been common to grip platform legs with shear pins, slips or
hydraulic rams. Such hydraulic rams shear pins or slips had to be
manually set. The gripping force upon the platform leg was not
necessarily related to the weight of the platform deck. Oftentimes,
a drilling platform becomes unleveled such that the forces upon
other platform legs may increase substantially. Existing devices
for leveling a platform require the gripping means to be released
from a platform leg before leveling forces can be applied.
Releasing the gripping means from one platform leg in order to
permit leveling necessarily increases the danger of the platform
sliding down the platform leg and creating stress upon the
remaining platform legs. Releasing the gripper means for leveling
purposes creates a danger of platform system failure.
In addition, if one jacking device failed, the stress upon the
remaining platform legs could increase substantially. The failure
of jacking systems presents a serious hazard to offshore drilling
operations. When the stress upon prior art jacking devices
increases, there is no mechanism to assure that the gripping force
upon the platform leg will also increase in response to such
stresses.
Prior art jacking systems are also unsatisfactory in that many such
systems require that shear pin holes be aligned or that gears be
meshed. Thus, the platform may not be jacked and leveled by moving
the platform any desired distance. The platform may be moved only
from one pin hole to another.
Prior art blowout preventer devices, used to prevent pipe from
being blow out of a hole during drilling operations typically use
hydraulic or threaded systems to grip the pipe. Such prior art
systems must be set by external gripping forces. Such devices
oftentimes cause hoop stresses upon the pipe when engaged. Because
the gripping force is not related to the force tending to push the
pipe out of the hole, the pipe must be gripped with an adequate
force to prevent a blowout regardless of the existence of any
downhole pressure. Thus, under substantially zero downhole pressure
conditions, the pipe tends to be overstressed. Moreover, existing
systems may be slow to engage. Prior art blowout preventer devices
require manual setting and are not automatic or self-engaging.
If a large downhole pressure suddenly develops, there is no
mechanism in such prior art blowout preventer devices to
automatically set or increase the gripping force. Thus, such prior
art devices are ineffective to prevent a blowout unless they have
previously been set upon the pipe with sufficient force to
withstand the sudden increase and in downhold pressure. Such prior
art blowout preventers must also be released in order to permit the
withdraw of casing, coupling or upset portions on the drill
string.
Prior art hanging systems for pipe, tubing and casing, such as
systems employed to prevent pipe from being dropped down into a
hole during workover and drilling operations, commonly referred to
as "hangers", and systems used to grip pipe going in and out of a
well, commonly referred to as "elevators" or "snubbers", required
that an expensive derrick be constructed at the drill site in order
to permit operation of the hanging device. Such prior art devices
typically employ slips that must be manually reset. In order to
pass casing, coupling or upset portions of the pipe or drill
string, such prior art devices require that the slips be released
and expanded to permit the pipe and casing to be passed. While the
slips are released for the passage of the casing, the safety
hanging device is inoperative. Thus, during such periods, the pipe
or drill string is exposed to the risk of being dropped into the
hole.
The adverse economic consequences and delays encountered when drill
pipe or other devices are dropped into a hole and the difficulty of
retrieving the pipe or such devices requires that a safety hanging
apparatus be available to guard against dropping the pipe at all
times during drilling operations.
In addition, many prior art hanging devices, including snubbers,
elevators and hangers, cannot take upward pressure upon the pipe
without impairing their operation.
While prior art arrangements have exhibited a degree of utility in
gripping a pipe, cylinder or tube, room for significant improvement
remains. The problems enumerated in the foregoing are not intended
to be exhaustive, but rather are among many which tend to impair
the effectiveness of previously known devices for gripping
cylinders or pipes. Other noteworthy problems may also exist;
however, those presented above should be sufficient to demonstrate
that the prior arrangements appearing in the art have not been
altogether satisfactory.
This invention relates generally to an apparatus for capping and
sealing the end of a pipe, tube or cylinder during hydrostatic
testing. More particularly, this invention concerns an apparatus
having a plurality of jaws pivotally mounted on a plurality of
arms, and the arms are in turn pivotally mounted to a body adapted
to axially receive a pipe, tube or cylinder. With jaws of an area
determined in accordance with the present invention the mechanical
pressure upon the outer wall of the pipe substantially equals or is
proportional to the fluid pressure upon the inner wall of the pipe.
Therefore, the wall of the pipe is compressed; the outer diameter
of the pipe is not substantially stressed. The apparatus is adapted
to cap the pipe during hydrostatic testing without generating
significant hoop stresses upon the pipe itself.
While the present invention is described with referenced to capping
a pipe, it is intended that "pipe" wherever used herein shall
include tubing or other cylindrical objects. The invention may also
facilitate grasping a cylindrical object for other purposes.
Hydrostatic testing of pipes, upset tubing, and other cylindrical
objects is necessary to insure that the pipe or tubing will
withstand pressure levels equal to or greater than those which are
expected to be encountered during use. Hydrostatic testing is
generally a requirement of the American Petroleum Institute
(A.P.I.) for most types of pipes.
In the absence of adequate hydrostatic testing during the
installation of a petroleum or oil by-product pipeline, hidden
flaws in the pipe may cause it to burst. An erupted pipe may go
undetected for relatively long periods of time and loose a
significant portion of its contents, which may have adverse
consequences for the environment. In addition, the adverse economic
consequences involved in repairing a broken pipeline and the
consequential down time can be severe. The resultant disruptions in
the supply of oil, natural gas, or other commodity intended to be
transported through the pipeline, in addition to the foregoing,
require pipe and tubing to be adequately tested hydrostatically
prior to or during the installation of such pipeline.
Manufacturing operations for producing pipe or tubing expected to
withstand pressure during use require hydrostatic testing as a
quality control measure. Unless pipe and upset tubing are tested,
undetected flaws can create serious safety hazards to an end user.
Therefore, hydrostatic pressure testing has become a practical
necessity for pipe, fittings and tubing after fabrication.
In the past, it has been common to weld a cap onto the end of a
pipeline or an unthreaded or unflanged pipe to be tested. Welding
requires expensive skilled labor to perform the welding operations.
This work cannot ordinarily be performed by unskilled laborers. The
cap must be securely welded to withstand test pressurization
without blowing off of the end of the pipe. In some cases, stress
relieving and X-raying of the welded cap is required. After
testing, the cap must be off of the pipe. Not only is welding
time-consuming and expensive, but also, the danger of explosion in
some environments may be so great that welding operations are not
feasible.
Prior art devices have included caps adapted to be screwed onto the
end of the pipe or tubing to be tested. Such devices utilize the
threads of the pipe to secure the device to the pipe. It is
believed that API specifications require that such devices be
tightened hand-tight only. Otherwise, the threads of the pipe may
be damaged. However, a hand-tight cap will not withstand high
pressure testing. Thus, to achieve a satisfactory seal, such
devices are often overtighened resulting in stripped threads and
damage to the pipe or fitting. Threads unknowingly stripped during
installation present a latent danger that can kill or injure if
pressurization causes the cap to blow off of the end of the pipe
during testing. Such devices may not have the structural integrity
to withstand testing pressures and may be blown off, thus
presenting a serious threat of injury.
Moreover, such devices must be tightened under substantially zero
internal pressure conditions because tightening during
pressurization is impractical and dangerous. During zero internal
pressure conditions there is no internal fluid pressure to offset
the clamping pressure. Thus, the threads and other portions of the
pipe must be stressed, and damage to the pipe or threads may
result. Clearly, such prior art devices are unusable on pipe with
damaged threads or no threads at all. It is often impractical to
machine new threads onto the end of the damaged pipe because of the
costs and delay involved. Thus, the cost of pipe ruined by such
devices renders these known devices impractical in many cases.
In order to safely perform a hydrostatic test, all air and other
gaseous matter must be expunged from the inner volume of the pipe.
Failure to remove substantially all of the air creates an explosion
hazard that can pose a serious danger to anyone in the vicinity of
the testing apparatus. Most prior art devices fail to have a
positive safeguard against such trapped air type explosions.
For example, in the past it has also been common to attach a cap
onto the end of a pipe with bolts, screws, or other fastening
means. Such methods of capping a pipe have been unsatisfactory,
however. Not only are such methods time-consuming, but injuries and
even deaths can result from such caps being blown off of the pipe
during high pressure testing, because such methods and apparatus
fail to provide a satisfactory means for eliminating air or gas
from the interior of the pipe.
Known methods of removing air from a pipe include tilting the
uncapped end of a joint of pipe in an upward direction, thereby
causing air bubbles to migrate to the raised end of the pipe. Such
tilting methods often result in pipe handling problems because the
pipe may slip or be dropped. The expense and time required for such
handling methods, in addition to the hazard posed when such pipe is
dropped or slips, renders such methods unsatisfactory. Moreover,
long sections of pipeline cannot be conveniently tilted or may be
too long for the pipe handling apparatus available.
Another example of a prior art mechanism utilizes a set of
independently operated jaws. Each jaw is manually tightened against
the pipe by means of a screw or bolt which is adjusted with a
wrench to jam the jaw against the pipe wholly independently of the
other jaws. This type of mechanism is unsatisfactory at least
insofar as it may create hoop stresses or deformations upon the
pipe. For high pressure testing, the jaws must be tightened to a
holding force sufficient to withstand test pressure before the pipe
is pressurized. This imposes excessive stresses on the walls of the
pipe which are likely to overstress, deform or weaken the pipe.
Other devices employ hydraulic rams and threaded devices to slips
which apply an outside force to hold the cap onto the pipe.
Necessarily, such devices must stress the outer wall of the pipe
while there is little or no internal pressure to offset the pipe
gripping force. If the initial gripping force is inadequate, the
cap will slip off during internal pressurization of the pipe. Such
known devices have a tendency to deform or damage the pipe.
Representative prior art patents illustrating problems of the type
overcome by the present invention are U.S. Pat. Nos. 2,699,802;
3,647,108; 3,765,560; 3,885,521; 1,746,071; 2,399,544; 2,445,645;
2,480,358; 2,851,061; 3,108,012; 3,125,464; 3,525,111; and
3,703,947.
U.S. Pat. No. 4,077,250, granted to applicant herein, discloses a
pipe closure apparatus having gripper means connected to a spline
or rib by means of a rotatable link attached to a mounting pin.
This patent failed to address the problem of removing air from the
pipe in order to reduce the hazard of explosion. Moreover, this
patent fails to address the problem of extrusion of the seal during
high pressure testing.
The earlier patent disclosed an alignment ring positioned axially
to the rear of a gripper means. The rotatable link was attached to
a spline or rib, which was in turn joined to the body of closure
plate. However, this arrangement was found to be unsatisfactory in
some instances. When pressure is introduced into the pipe, the
gripper means is urged in a direction generally toward the rear of
the body. The gripper means therefore urges the spline or rib
generally radially outward. Difficulties were encountered in
manufacturing a commercially practical spline or rib adequate to
withstand the radially outward force generated by the gripper means
during high pressure testing. It was found that an enormous rib was
required to withstand high pressure testing because of the manner
in which the load was transmitted to the rib in the earlier
patent.
The prior art patent also has failed to address the problem created
by dirt, grime or air which may become entrapped within a U-shaped
seal. The entrapment of air, dirt, debris or other foreign matter
within a seal may inhibit, if not render inoperative, the intended
operation of the seal. Nor did the earlier patent have a pre-loaded
lip to assure zero leakage during low pressure filling of the
pipe.
The earlier patent was not adapted for testing pipe with upsets,
bell ends or coupling ends. In order to pass such pipe ends, the
alignment ring had to be made too large to effectively align the
pipe during testing. That patent had no centralizer means for
centering such a pipe after passing the larger end of the pipe.
The earlier patent teaches the use of a single rotatable link
joining a gripper to a rib. A single link has proved to be
unsatisfactory in some instances. A single link introduces
stability problems and may create undesirable stresses upon the
diameter of a pipe and the rib. Moreover, the earlier patent fails
to address the unexpected uneven distribution of the load forces
upon the pipe achieved by the gripper means disclosed in that
patent where the gripper means is not permitted to move generally
parallel to the axis of the pipe.
The prior patent was not adaptable to test several different pipe
sizes with a single apparatus. The prior patent failed to provide
means for readily adapting the apparatus to fit different pipe
sizes.
While prior art arrangements have exhibited a degree of utility in
capping the end of a pipe or tube to permit hydrostatic testing,
room for significant improvement remains. The problems enumerated
in the foregoing are not intended to be exhaustive, but rather are
among many which tend to impair the effectiveness of previously
known apparatus for capping pipes. Other noteworthy problems may
also exist; however, those presented above should be sufficient to
demonstrate that the poor arrangements appearing in the art have
not been altogether satisfactory.
SUMMARY OF A PREFERRED EMBODIMENT OF THE INVENTION
Recognizing the need for an improved apparatus for gripping a
cylinder or pipe for hydrostatic testing for jacking operations
upon offshore drilling platforms, for gripping drill pipe to
prevent a blowout and for gripping drill pipe, tubing and casing in
safety hanging systems and other wellhead workover applications, it
is, therefore, a general intent in disclosing the present invention
to provide a novel apparatus for gripping a cylinder, pipe or tube,
which minimizes or reduces the problems of the type previously
noted. The present invention has further useful application in
gripping a pipe, tube or cylinder for other purposes.
A feature of the cylinder gripping apparatus resides in the ability
to permit the cylinder, pipe or tube to move in one direction with
respect to a body, and to prevent the cylinder from moving in a
second opposite direction with respect to the body. A correlated
feature resides in the ability of the cylinder gripping apparatus
to grip the pipe with a force which is proportional to the axial
force upon the pipe tending to move the pipe with respect to the
body. In an application as a blowout preventer, the cylinder
gripping apparatus includes the more detailed feature of increasing
its grip upon the pipe in response to an increase in downhole
pressure tending to forced the pipe out of the well. Thus, a sudden
increase in downhole pressure will result in a sudden increase in
the gripping force upon the pipe.
A feature resides in the provision of floating lugs which allow
jaws to grip a cylinder, pipe or tube with a proportional gripping
force which opposes rotational movement of the cylinder.
In an application as a snubber, the invention includes the feature
of back-to-back gripping apparatus which grip pipe in both axial
directions while tubing is installed or removed. One set of
back-to-back gripping apparatus holds the tubing while another
back-to-back apparatus reciprocates axially to jack the tubing in
or out of the well. During this operation, the tubing is secured at
all times in both axial directions. The gripping means of the
present invention has the additional feature of incorporating lugs
which will not only grip the pipe axially but will grip the pipe
with a force proportional to a rotational torque for making up or
unscrewing joints of pipe.
Of independent significance, the gripping apparatus includes an
interfacing assembly which is more economical to construct and
operate. A more detailed feature resides in the utilization of
force translation lugs to interface the jaw with the cylinder. The
utilization of such force translation lugs renders the cylinder
gripping apparatus inexpensive to construct and simple to
operate.
Yet another feature of the cylinder gripping apparatus is the
provision for an interfacing assembly which permits the jaw to be
easily aligned with the cylinder, even when the cylinder is not
axially centered within the body. The interfacing assembly permits
radial, axial and transverse movement of the jaw with respect to
the body in order to permit the jaw to correctly align itself upon
the cylinder.
In an application as a drilling platform jacking apparatus, the
cylinder gripping apparatus includes the related feature of
providing a jacking apparatus which increases its grip upon the
platform leg in response to increased pressures generated by
unleveling of the platform deck or the failure of a jacking
apparatus upon another leg of the platform. This feature reduces
the incidence of failure of the jacking apparatus.
A cylinder gripping apparatus according to a presently preferred
embodiment of the invention intended to substantially incorporate
the foregoing features includes a jaw adapted for gripping a
cylinder, a body adapted to axially receive the cylinder, and an
interfacing assembly. The interfacing assembly is interposed
between the jaw and the body and is adapted to urge the jaw into
gripping engagement with the cylinder when the cylinder is urged in
a first direction with respect to the body. The interfacing
assembly is adpated to allow the jaw to release from the cylinder
when the cylinder is moved in a second direction with respect to
the body.
The interfacing assembly is adapted to provide a radial gripping
force in response to an axial force upon the cylinder which is
proportional to that axial force. The interfacing assembly is
adapted to permit radial, axial and transverse movement of the jaw
with respect to the body in order to permit the jaw to align itself
upon the cylinder when the cylinder is not perfectly centered
within the axis of the body or when the cylinder is deformed.
The interfacing assembly may comprise a force translation lug which
is engagable within bearing grooves upon the jaw and the body.
The interfacing assembly may also comprise a plurality of generally
cylindrical rollers interposed between the jaw and the body. In
this embodiment, the body has an inclined side wall. The rollers
are operable to facilitate the movement of the jaw relative to the
body along the inclined side wall of the body in order to urge the
jaw into gripping engagement with the cylinder. Channels adapted to
receive the cylindrical rollers may be formed either in the jaw or
in the side wall of the body.
The interfacing assembly may alternatively comprise a cam arm
pivotally attached to the body having a generally arcuate cam
surface. The jaw may have a groove adapted to receive the cam
surface of the cam arm. The cam arm is operable to urge the jaw
into engagement with a cylinder when the cam arm is rotated with
respect to the body.
Employed as a platform jacking apparatus, the cylinder gripping
apparatus may employ two sets of jaws. One set of the jaws is
operable to grip the platform leg while the other set is released.
Actuating means or hydraulic cylinders are connected to one set of
the jaws to provide a means for jacking the platform deck up upon
the platform leg.
Examples of the more important features of this invention have thus
been summarized rather broadly in order that the detailed
description thereof that follows may be better understood, and in
order that the contribution to the art may be better appreciated.
There are, of course, additional features of the invention that
will be described hereinafter and which will also form the subject
of the claims appended hereto. Other features of the present
invention will become apparent with reference to the following
detailed description of a presently preferred embodiment thereof in
connection with the accompanying drawings, wherein like reference
numerals have been applied to like elements.
Recognizing the need for an improved method and apparatus for
capping an end of a pipe for hydrostatic testing, it is, therefore,
my general intent in disclosing the present invention to provide a
novel method and apparatus for capping an open end of a pipe, which
minimizes or reduces the problems of the type previously noted. The
present invention has further useful application in gripping a
pipe, tube or cylinder for other purposes.
A feature of the capping apparatus resides in a particular
geometric arrangement of the arms, jaws and body, such that during
hydrostatic testing, hoop stresses or undesirable forces imposed by
the jaws and arms onto a pipe are minimized. A further feature of
the invention resides in a novel centralizer adapted to axially
center the pipe within the body of the apparatus.
Yet another feature of the invention resides in the novel
arrangement of an air purge valve with passageways interconnecting
the valve to a pressurized region within the interior region of the
body in the pipe. The purge valve is adapted to expunge trapped air
from the pressure zone. This feature reduces the hazard of
explosions caused by air feature reduces the hazard of explosions
cause by air trapped within the pressurized region within the
interior of a pipe capped in accordance with the invention.
An additional feature of my invention resides in the adaptability
of the apparatus to a wide range of pipe diameters and pipe
surfaces. Replaceable jaw tooth segments, interchangeable cam piece
surfaces, and adapters facilitate the hydrostatic testing of
varying pipe sizes and permit the movement of pipe couplings,
upsets and bell ends through or into the apparatus of the present
invention.
Of independent significance is the feature residing in the novel
arrangement of a flexible member seal, a spacer and a ring. The
ring is adapted to slide into contact with the pipe surface and
prevent the extrusion of the seal during high pressure testing.
Another feature pertains to the particular arrangement for
connecting the jaw tooth segment to an arm.
A further feature of my invention resides in the ability to
hydrostatically test pipe or tubing without deforming the pipe or
tubing, even under high pressure testing. The mechanical force per
square inch applied to the surface of the pipe by my testing
apparatus is proportional to the invention pressure per square inch
of the fluid or water upon the inside surface of the pipe. Thus, as
a practical matter, only the wall of the pipe is compressed by
proportionally opposite pressure forces; the outer diameter of the
pipe is not substantially stressed.
Of independent significance is the feature pertaining to the novel
means for engaging and disengaging the jaws upon the pipe. This
feature resides in the quick placing of the apparatus upon the pipe
to easily secure a safe sealing engagement of the end of the pipe
and to minimize the time required to handle the apparatus. An
engagement means is disclosed for accurately aligning the jaws with
synchronized sleeves.
In using the apparatus of this invention, nothing is screwed on the
pipe or tubing, nothing is screwed off, and nothing is forced onto
the pipe or tubing. Threads are not necessary to facilitate capping
in the pipe. Existing threads are not used. No significant outside
force is required to hold the testing apparatus to the pipe or
tubing. The force applied to hold the apparatus to the pipe is self
generating and is always proportional to the internal pressure of
the pipe, providing an added safety feature; the greater the
pressure, the harder the holding force.
Moreover, a feature of my invention pertains to the ability to test
over upsets, threads and couplings. A related feature is the
ability to cap the end of the pipe without damaging the pipe
threads or couplings.
A collateral feature of my invention is the speed and ease with
which pipe or tubing may be tested. Skilled welders are not
required. Untrained workers may easily, quickly and safely install
my apparatus to pipe or tubing. Many man-hours may be saved. The
apparatus may be operated for long periods with minimal wear and
maintenance. Hydrostatic testing may be performed quickly,
economically and safely.
A further feature of my invention resides in the adaptability of
the apparatus to serve as an end closure. Appropriate means may be
provided to join two of my apparatus together with a bore through
the front wall of the caps to provide a weldless joint between two
pipe sections for connecting such pipe when welding operations are
not feasible, due to the danger of explosion or otherwise. A valve
or other device may also be attached to the end of a pipe.
Another feature of may invention resides in the operability of my
apparatus despite the presence of oil, dirt, rust or mill scale on
the pipe. The jaw tooth segment is adaptable to grip such pipe; and
the seal is operable to seal such pipe.
Finally, a feature of my invention pertains to the adaptability of
my apparatus for hydrostatically testing a varity of pipe end
types, including, for example, plain end pipe, threaded pipe,
threaded casing, threaded non-upset tubing, threaded pipe with
made-up coupling, casing with made-up coupling, upset tubing with
made-up coupling, non-upset tubing with made-up coupling, external
upset tubing with and without made-up coupling, and bell end pipe.
It will be appreciated that other types of pipe, tubing or other
cylindrical objects may also be capped or held with the disclosed
invention.
A pipe capping apparatus according to a presently preferred
embodiment of the invention intended to substantially incorporate
the foregoing features includes, in addition to the elements
enumerated above, a body and a plurality of jaws mechanically
coupled through a radial translator adapted to translate an axial
pressure force upon the body into a radial force that is evenly
applied to the outside wall of a pipe. The body, radial translator
and jaws operate to sealingly hold the end of the pipe to
facilitate pressurization. A pressure barrier apparatus comprising
a flexible seal, and a spacer and an extrusion inhibiting ring
included for high pressure testing, cooperates in sealingly
engaging the pipe.
More specifically, the flexible seal has a pair of lips formed upon
a seal body. The lips define a pressure zone between the lips that
also facilitates flushing debris, dirt and rust from the seal and
allows trapped air to escape. Lugs upon the seal pre-stress the
seal to facilitate initial engagement of the lips.
A tension plate is provided to facilitate the construction of a
more economical and stronger body able to withstand the forces
imposed on the pipe capping apparatus during high pressure
testing.
A plurality of cantilevered arms pivotally attached to the body are
provided to axially center the pipe within the body. Drive means
engage a drive surface upon the cantilevered arms to rotate the
cantilevered arms. A handle serves as a means for actuating the
drive means.
An improved attachment arrangement is provided to couple the jaw to
the body. In particular, dual links are provided which result in a
more stable linkage between the jaw and the body. Other
arrangements for coupling the jaw to the body are also
disclosed.
Example of the more important features of this invention have thus
been summarized rather broadly in other that the detailed
description thereof that follows may be better understood, and in
order that the contributed to the art may be better appreciated.
There are, of course, additional features of the invention that
will be described hereinafter and which will also form the subject
of the claims appended hereto. Other features of the present
invention will become apparent with reference to the following
detailed description of a presently preferred embodiment thereof in
connection with the accompanying drawings, wherein like reference
numerals have been applied to like elements, in which:
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 depicts a partial cutaway side view of an embodiment of a
pipe capping apparatus constructed in accordance with the present
invention.
FIG. 2 shows an end view of the pipe capping apparatus of FIG. 1
illustrating the centralizer.
Similar to FIG. 2, FIG. 3 shows another end view of the
centralizer. FIG. 4 shows a front view of an alternative embodiment
of a jaw, jaw holder and arm.
FIG. 5 is a partialy cutaway side view of the embodiment depicted
in FIG. 4.
FIG. 6 shows an elevation view of the pressure barrier apparatus
depicting the lugs and interstices between the lugs.
FIG. 7 shows a cross-sectional view of the pressure barrier
apparatus taken through section lines 7--7 in FIG. 6.
FIG. 8 shows a cross-sectional view of the pressure barrier
apparatus for low pressure applications, the surface of the pipe,
and the surface of the body.
FIG. 9 illustrates a cross-sectional view of an alternative
embodiment of a pressure barrier apparatus for high pressure
applications.
FIG. 9A illustrates an enlarged view of a portion of FIG. 9.
FIG. 10 is another view of the apparatus depicted in FIG. 9,
showing the apparatus during pressurization.
FIGS. 10A and 10B illustrate enlarged views of portions of FIG.
10.
FIG. 11 and FIG. 12 show a cross-sectional elevational view of the
ring illustrated in FIG. 9.
FIG. 12 shows a view of the ring illustrated in FIG. 11 during
pressurization.
FIG. 13 and FIG. 14 illustrate an alternative embodiment of the
ring depicted in FIG. 11 and FIG. 12, respectively.
FIG. 15 illustrates a cross-sectional elevational front view of the
interface between the jaw tooth segment and the wall of the
pipe.
FIG. 16 is a partial cross-sectional side view of an alternative
embodiment of the means for engaging and disengaging the jaws upon
the pipe.
FIG. 17 is an additional side view of the embodiment disclosed in
FIG. 16 showing the jaws retracted.
FIG. 18 depicts a side view of another alternative embodiment of
the means for engaging and disengaging the jaws upon the pipe.
FIG. 19 shows an additional side view of the apparatus illustrated
in FIG. 18 showing the jaws retracted.
FIG. 20 depicts a side view of an embodiment of a cylinder gripping
apparatus constructed in accordance with the present invention.
FIG. 21 shows a cut-away end view of the cylinder gripping
apparatus depicted in FIG. 20.
FIG. 22 shows a side view of an alternative embodiment of the
cylinder gripping apparatus.
Similar to FIG. 22, FIG. 23 shows a side view of the embodiment
illustrated in FIG. 22 depicting the retainers or stays.
FIG. 24 illustrates a partially cut-away end view of the embodiment
depicted in FIG. 23.
FIG. 25 is a side view of an alternative embodiment of the cylinder
gripping apparatus.
FIG. 26 is a side view of yet another alternative embodiment of the
cylinder gripping apparatus.
FIG. 27 illustrates a side view of an alternative embodiment of the
cylinder gripping apparatus.
FIG. 28 depicts a partially cut-away side view of an embodiment of
the cylinder gripping apparatus employed as a safety hanging
apparatus for a pipe.
FIG. 29 shows an enlarged side view of the force translation lug
and the bearing groove in the body.
FIG. 30 illustrates a cut-away bottom view of the apparatus shown
in FIG. 29.
FIG. 31 shows a partially cut-away bottom view of the apparatus
illustrated in FIG. 28.
FIG. 32 depicts an embodiment of the cylinder gripping apparatus
employed as a drilling platform jacking apparatus.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION
Turning now to the drawings in FIG. 20, there is depicted a side
view of a portion of a cylinder gripping apparatus 200. The
cylinder gripping apparatus 200 comprises a body 201, a jaw 202 and
an interfacing assembly 203. The body 201 is only partially shown
in FIG. 20.
As best shown in FIG. 21, the jaw 202 has a friction surface 204
adapted for gripping a cylinder 205. The friction surface 204 may
comprises serrations, teeth, a smooth friction surface, or other
conventional friction surfaces.
With reference to FIG. 20, the interfacing assembly 203 may
comprise floating force translation lugs 206. The interfacing
assembly also comprises a resilient member, elastic member or
spring 207. The elastic member 207 is connected to the jaw 202 at a
first spring anchor point 208. The elastic member 207 is connected
to the body 201 at a second spring anchor point 209.
The floating force translation lugs 206 are floating in the sense
that the lugs 206 are unconnected to either the body 201 or the jaw
202. The lugs 206 fit into first bearing grooves or sockets 210
formed in the jaw 202. The other end of the lugs 206 fit into
second bearing grooves or sockets 211.
As shown in FIG. 21, the lug 206 has a first arcuate end or curved
end 212 and a second arcuate or curved end 213. The first arcuate
end 212 is adapted to fit into the first bearing groove 210.
Similarly, the second arcuate end 213 is adapted to fit into the
second bearing groove 211.
As best shown in the side view depicted in FIG. 20, the forced
translation lugs 206 are angularly disposed between the body 201
and the jaw 202. The first bearing groove 210 has a first arcuate
or curved bearing surface 214 which tapers to a sloped forward
surface 215. The sloped forward surface 215 allows the lug 206 to
rotate in a first sense inside the first bearing groove 210. In
FIG. 20, the first sense of rotation is clockwise with respect to
the jaw 202.
Similarly, the second bearing groove 211 comprises a second arcuate
or curved bearing surface 216 which tapers to a sloped or planar
rearward surface 217. The sloped rearward surface 217 permits the
lug 206 to rotate in a first sense with respect to the body
201.
The lugs 206 are floating and thus unconnected to the body 201 or
the jaw 202. Therefore, it is desirable to provide a means for
compressively engaging the jaw 202 toward the body 211 in order to
hold the lugs 206 within the first and second bearing grooves 210
and 211. In the present instance, this is essentially accomplished
by the elastic member 207. When the jaw 202 is not engaged against
a cylinder 205, the elastic member 207 tends to urge the jaw 202
toward the body 201, thus holding the lugs 206 in engagement within
the first and second bearing grooves 210 and 211.
It will be appreciated that some actuating means may be provided to
urge the jaw 202 into initial engagement with the cylinder 205.
When the jaw 202 is engaged against a cylinder 205 and an axial
force urges the cylinder 205 in a forward direction, or to the
right in FIG. 20, then the lugs 206 will tend to rotate in a second
sense, or counterclockwise in FIG. 20. The tendency of the lugs 206
to rotate in a second sense will tend to urge the jaw 202 into
gripping engagement with the cylinder 205. The gripping force
between the jaw 202 and the cylinder 205 will be proportional to
the axial force exerted upon the cylinder 205. Thus, the force
translation lugs 206 provide a radial counterforce in response to
the axial force upon the cylinder.
When the cylinder 205 is not perfectly axially aligned with respect
to the body 201, it is desirable to permit the jaw 202 to move in a
direction transverse to the axis of the body 201. As best shown in
FIG. 21, it is desirable to allow the jaw 202 to move transversely,
i.e., to the left or right, in order to allow the friction surface
204 to engage the cylinder 205. The curved ends 212 and 213
cooperate with the first opposing face 218 of the jaw 202 and the
second opposing face 219 of the body 201 to permit a transverse
displacement of the jaw 202 from an initial axially aligned
position to a displaced position either to the right or to the left
of FIG. 21. Thus, the floating lug 206 permits the friction surface
204 of the jaw 202 to engage the cylinder 205 even when the
cylinder 205 is not perfectly axially aligned within the body
201.
Thus, the floting nature of the lug 206 which is interposed between
the jaw 202 and the body 201 permits movement between the jaw 202
and the body 201 with at least three degrees of freedom. That is,
the jaw 202 may move axially, radially and transversely with
respect to the body 201. These degrees of freedom of movement that
are permitted the jaw 202 with respect to the body 201 facilitate
the effective engagement of the jaw 202 against the cylinder 205
even for imperfectly aligned cylinders 205.
In some applications, such as a wellhead snubber apparatus, it may
be desirable to grip a pipe, tube or cylinder 205 to prevent
rotation of the pipe, tube or cylinder 205 about the axis of the
body 201. As shown in FIG. 21, the floating lug 206 may be
positioned in offset position 400 (shown as a broken line). In the
offset position 400, the lug 206 will tend to oppose clockwise
rotation of the pipe 205. The gripping force of the jaw 202 upon
the pipe 205 will be proportional to the clockwise torque upon the
pipe 205. Similarly, counterclockwise rotation of the pipe 205 may
be prevented by a jaw 202 with the lug 206 offset in an opposite
direction, or to the right in FIG. 21 (not shown).
It will be appreciated that a second cylinder gripping apparatus
200 may be connected to the same pipe 205 as a first gripping
apparatus 200 with a set of lugs 206 offset in an opposite
direction in order to prevent both clockwise and counterclockwise
rotation of the same pipe 205.
Turning now to FIG. 22, another embodiment of the interfacing
assembly 203 is shown. The interfacing assembly 203 comprises
floating lugs 220 interposed between the body 201 and the jaw 202.
The floating lugs 220 may be fabricated differently from the lugs
206 illustrated in FIGS. 20 and 21. As best shown in FIG. 24, the
lug 220 has a first curved or arcuate end 221 and a second curved
or arcuate end 222. The first curved end 221 is wider than the
second curved end 222. The first curved end 221 may be
substantially the same width as the jaw 202. As best shown in FIG.
24, the first bearing groove 210 may extend across substantially
the entire width of the jaw 202.
The first end 221 of the lug 220 may be held within the first
bearing groove 210 by a set of first stays or retaining means 223.
The first stays 223 are fixedly held against the jaw 202 by
fastening means 224. Fastening means 224 may comprise a bolt,
screw, pin, or other conventional fastening mechanisms.
Similarly, the second end 222 of the lug 220 may be held within the
second bearing groove 211 by a set of second stays or retaining
means 225. The second stays 225 are fixedly held against the body
201 by fastening means 226. Fastening means 226 may comprise a
bolt, screw, pin, or other conventional fastening mechanisms.
Fastening means 224 and 226 are connected to the jaw 202 and the
body 201, respectively. The first and second stays 223 and 225 are
not connected to the lug 220. This can best be seen with reference
to FIG. 23. The first and second stays 223 and 225 are adapted to
cover at least a portion of the cross-sectional area of the first
and second bearing surfaces or grooves 210 and 211 in the jaw 202
and the body 201, respectively. The first and second stays 223 and
225 are adapted to laterally retain the lug 220 within the first
and second bearing grooves 210 and 211, while leaving the lugs 220
free to rotatively pivot within the bearing grooves 210 and
211.
The stays 223 and 225 may be omitted, as shown in FIG. 22, and are
not essential for the operation of the cylinder gripping
apparatus.
Thus, as shown in FIG. 22, the first and second curved ends 221 and
222 of the lug 220 cooperate with first and second opposing faces
218 and 219 of the jaw 202 and the body 201, respectively, to
permit a transverse displacement of the cylinder 205 from an
initial axially aligned position to a displaced position. This
degree of freedom of movement of the jaw 202 in the transverse
direction permits the jaw 202 to more evenly engage the cylinder
205 when the cylinder 205 is not perfectly axially aligned within
the body 201.
As shown in FIG. 22, the opposing face 218 of the jaw 202 has a
curved surface or bearing groove 210 adapted to receive the curved
end 221 of the floating lug 220.
An elastic member 207 tends to urge the jaw 202 toward the body 201
in order to hold the lugs 220 into engagement within the first and
second curved surfaces 210 and 211. A compression member or spring
227 tends to urge the jaw 202 into engagement with the cylinder
205. As shown in FIG. 22, the compression member 227 is interposed
between the front of the body 201 and the jaw 202.
Actuating means 228 is connected to the lug 220 for rotationally
pivoting the lug 220. Actuating means 228 may comprise a handle.
Actuating means 228 may be used to rotationally pivot the lug 220
in a first sense, or clockwise as shown in FIG. 22, to permit the
jaw 202 to disengage the cylinder 205.
It will be noted that the elastic member 207 tends to urge the jaw
202 radially outwardly with respect to the body 201, thus urging
the lugs 220 into operative engagement with the first and second
bearing grooves 210 and 211. When the cylinder 205 is removed from
the body 201, the elastic member 207 tends to hold the jaw 202 and
the body 201 into engagement with the lugs 220.
As shown in FIG. 23, the first bearing groove 210 comprises a first
curved or arcuate bearing surface 214 which tapers to a sloped or
planar forward surface 215. Similarly, the second bearing groove
211 comprises a second curved or arcuate bearing surface 216 which
slopes to a planar or sloped rearward surface 217.
It will be appreciated that a floating force translatin by 206 may
be constructed with a first arcuate, curved or spherical end 212 as
shown in FIGS. 20 and 21, and with a second end fashioned in
accordance with the embodiment described above with reference to
FIGS. 22, 23 and 24.
Referring to FIG. 25, a side view of another embodiment of the
present invention is illustrated. The interfacing assembly 203 is
interposed between the sidewall of the body 201 and the jaw 202. In
the present instance, the interfacing assembly 203 has curved or
arcuate surfaces 229 which engage an opposing face 230 of the
sidewall of the body 201. The curved or circular surfaces 229 form
the outer surface of generally cylindrical or circular rollers 231.
In a preferred embodiment, the rollers 231 are formed in the shape
of cylindrical rods.
The rollers 231 are adapted to fit within channels 234 in the jaw
202. The channels 234 are formed transversely along the inner
surface 235 of the jaw 202. As shown in FIG. 25, the inner surface
235 of the jaw 202 is inclined or sloped. Similarly, the opposing
face 229 of the sidewall of the body 201 is similarly sloped or
inclined.
The rollers 231 are floating, and are thus unconnected to either
the jaw 202 or the body 201. The elastic member 207 tends to urge
the jaw 202 radially outwardly toward the sidewall of the body 201.
Thus, the elastic member 207 tends to hold the rollers 231 in the
channels 234.
The rollers 231 facilitate the movement of the jaw 202 along the
planar sloped opposing face 230 of the body 201. The rollers 231
are operable to facilitate the movement of the jaw 202 relative to
the body 201 along the inclined inner surface 230.
The inclined inner surface 230 is adapted to urge the jaw 202 into
engagement with the outer surface of the cylinder 205 when the jaw
202 is urged rearwardly, or to the right in FIG. 25, with respect
to the body 201. A compression member, resilient member or spring
227 is adapted to urge the jaw 202 rearwardly with respect to the
body 201.
Actuating means 232 is pivotally connected to the body 201 at a
pivot point 233. Actuating means 232 may comprise a handle, in a
preferred embodiment. Actuating means 232 is adapted to urge the
jaw 202 generally forwardly, but that is to the left in FIG. 25,
with respect to the body 201. Thus, actuating means 232 may be used
to disengage the jaw 202 from the cylinder 205.
The rollers 231 may be confined to the channels 234 by stays 225
(not shown).
Because the rollers 231 are floating, the jaw 202 is permitted to
move transversely with respect to the body 201. This transverse
movement of the jaw 202 permits the jaw to grip the cylinder 205
even when the cylinder 205 is not axially centered within the body
201. Thus, the curved surface of the rollers 231 is cooperable with
the opposing face 230 of the body 201 to permit a transverse
displacement of the jaw 202 from an initial axially aligned
positioned to a displaced position.
It will be appreciated that the channels 234 are preferably
generally cylindrically shaped in substantial correspondence with
the shape of the rollers 231. A first boss, finger or projection
236 limits the transverse movement of the jaw 202 with respect to
the body 201. The boss 236 prevents the jaw 202 from completely
slipping out of the cylinder gripping apparatus 200. Similarly, a
second boss, finger or projection 237 is formed upon the rear of
the jaw 202.
FIG. 26 illustrates an alternative embodiment of the interfacing
assembly 203 interposed between the jaw 202 and the body 201.
In the present instance, generally cylindrical roller 238 have
curved, arcuate or generally round surfaces 239 which are
cooperable with an opposing planer inclined face 240 of the jaw 202
to permit movement of the jaw 202 with respect to the body 201. The
rollers 238 fit within generally cylindrically shaped channels 241
formed transversely along the inclined or sloped inner surface 230
of the side wall of the body 201. The rollers 238 permit the jaw
202 to move transversely with respect to the body 201 in a manner
similar to the interfacing assembly described with reference to
FIG. 25.
In other respects the interfacing assembly 203 depicted in FIG. 26
is constructed and operated similar to the interfacing assembly 203
described with reference to FIG. 25.
Turning now to FIG. 27, the interfacing assembly 203 is interposed
between the body 201 and the jaw 202. In the present instance, the
interfacing assembly 203 has a curved surface 242 which interfaces
with an opposing face 243 of the jaw 202. The opposing face 234 of
the jaw 202 is located generally opposite to the friction surface
204 of the jaw 202.
The opposing face 234 of the jaw 202 has a curved surface or groove
244 formed in a position generally in correspondence with the
curved surface 242 of the interfacing assembly 203. The curved
surface 242 of the interfacing assembly 203 is cooperable with the
opposing face 234 of the jaw 202 to permit the jaw 202 to move not
only radially and axially with respect to the body 201, but also
transversely with respect to the body 201. Thus, if the cylinder
205 is not axially centered within the body 201, the curved surface
242 will permit the jaw 202 to move from an initial axially
centered position to a displaced position in correspondence with
the uncentered or displaced position of the cylinder 205. Thus, the
interfacing assembly 203 permits the jaw 202 to be displaced
transversely with respect to the body 201 in order to more
effectively engage the cylinder 205 when the cylinder 205 is
deformed or uncentered within the body 201.
The interfacing assembly 203 further comprises a cam arm or force
translation arm 245 which may be pivotally connected to the body
201 at a second pivot point 246. The cam arm 245 is operable to
urge the jaw 202 into engagement with the outer surface of the
cylinder 205 when the cam arm 245 is rotated in a second sense, or
counterclockwise in FIG. 27, with respect to the body 201.
Elastic members or springs 247 are connected to the jaw 202 at
first spring anchor points 248 and are connected to the body 201 at
second spring anchor points 249. The elastic members 247 tend to
urge the jaw 202 radially outwardly with respect to the body 201.
Thus, the elastic members 247 tend to urge the jaw 202 into
engagement with the generally arcuate cam surface 242 of the cam
arm 245.
In the present instance the jaw 202 has a forward alignment lip 250
and a rear alignment lip 251. The alignment lips 250 and 251 are
connected to the forward and rear edges of the jaw 202
respectively, as shown in FIG. 27. The alignment lips 250 and 251
operate to disengage the entire jaw 202 from the cylinder 205 in
the event that either the forward or rear end of the jaw 202 does
not initially disengage from the cylinder 205. If the cam arm 245
is rotated in a first sense, or clockwise in FIG. 27, with respect
to the body 201, the jaw 202 will be urged radially outwardly from
the cylinder 205 by the elastic members 247. In the event that the
rear portion of the jaw 202 does not initially disengage from the
cylinder 205, the forward alignment lip 250 will contact the inner
surface 219 of the body 201. Thus, further rotation of the cam arm
245 in a first sense with respect to the body 201 will cause the
jaw 202 to pivot about the point where the forward alignment lip
250 contacts the inner surface 219 of the body 201 and will cause
the rear portion of the jaw 202 to disengage from the cylinder
205.
In the present invention, the cam arm 245 has actuation means or a
handle 252 connected to it. An elastic member or spring 253 may be
connected between the handle 252 and the body 201. The elastic
member 253 will tend to urge the cam arm 245 to rotate in a second
sense with respect to the body 201 and thus urge the jaw 202 into
engagement with the cylinder 205.
It will be appreciated that the interfacing assemblies 203
illustrated in FIGS. 22, 25, 26 and 27 are adapted to provide a
radial counterforce in response to an axial force upon the
cylinder. If an axial force is exerted upon the cylinder 205 when
the jaw 202 is in engagement with the cylinder 205, and the
cylinder 205 is urged to the right in FIGS. 22, 25, 26 and 27, the
interfacing assemblies 203 will provide a radial counterforce or
gripping force which is proportional to the axial force exerted
upon the cylinder 205.
It will also be appreciated that, similar to FIG. 27, the
interfacing assembly 203 illustrated in FIGS. 20, 21, 22, 23 and 24
may be pivotally connected at one end to either the jaw 202 or the
body 201.
In FIG. 28, an embodiment of the present cylinder gripping
apparatus is shown for use in connection with a safety hanger or
blowout preventer apparatus for use in connection with drilling
operations. The embodiment illustrated in FIG. 28 may also have
utility as a snubber.
As illustrated in FIG. 28, the body 201 has an upper cylinder, pipe
or tube passageway or opening 254 and a lower pipe, tube or
cylinder passageway or opening 255. The body 201 is adapted to
axially receive the pipe, tube or cylinder 205. The jaws 202 have a
friction surface 204 adapted to grip the drill pipe 205.
In the present instance, the interfacing assembly 203 comprises
angularly disposed floating force translation lugs or arms 256. The
lug 256 is floating because it is unconnected to the body 201 or
the jaw 202. The lug 256 has a first curve surface or arcuate
surface 257 on one end and a second curved or arcuate surface 258
on the other end. The first curved end 257 is adapted to fit within
a first bearing groove 259. Similarly, the second curved end 258 is
adapted to fit within a second bearing groove 260. The bearing
grooves 259 and 260 are constructed similar to the bearing grooves
211 and 214 illustrated in FIGS. 22, 23 and 24. For example, as
best shown in FIG. 29, the second bearing groove 260 comprises a
second curved or arcuate bearing surface 261 which tapers to a
generally planar or inclined surface 262.
As best shown in FIG. 29, the lug 256 is floating in the sense that
it is not connected to the body 201. First and second retaining
means or stays 265 and 266 are connected or fastened to the jaw 202
and the body 201 respectively. The stays 265 and 266 retain the
lugs 256 when the pipe 205 is withdrawn from the body 201, as will
be more fully described below.
Referring to FIG. 29, the stay 266 has an aperture or opening 263.
The aperture 263 is adapted to receive a projection or pin 264
connected to the lug 256. As best shown in FIG. 30, the pin 264 is
connected to the lug 256 and extends through the aperture 263 in
the stay 266. When the jaw 202 engages the pipe 205, the lug 256
engages the grooves 259 and 260. When the lug 256 is engaged with
the grooves 259 and 260, the pin 264 does not contact the stay 266.
As best shown in FIG. 29, the aperture 263 is larger than the pin
264. Thus, the lug 256 is essentially floating. The pin 264
cooperates with the stay 266 to retain the lug 256 when the pipe
205 is withdrawn from the body 201.
As best shown in FIGS. 29 and 30, the stay 266 is connected to the
body 201 by fastening means 267. Fastening means 267 may comprise a
bolt, screw, pin or other conventional fastening mechanisms.
Referring to FIG. 28, the first stay 265 is similarly connected to
the jaw 202. In addition, the lug 256 has a corresponding pin 268
which is adapted to fit within an aperture in the first stay 265.
It will be appreciated that either end of the lug 256 may be
pivotally connected to the body 201 or jaw 202.
The operation of the interfacing assembly 203 illustrated in FIGS.
28 through 31 and providing a radial counterforce or gripping force
upon the pipe 205 in response to an axial force upon the pipe 205
is similar to the interfacing assemblies 203 described above with
reference to FIGS. 20 through 27.
The interfacing assembly 203 illustrated in FIG. 28 further
comprises a jaw housing 269. The jaw housing 269 has arm passage
openings 270 which permit the lugs 256 to pass through the jaw
housing 269. A compression member or spring 271 is provided between
the body 201 and the jaw housing 269. The spring 271 tends to urge
the jaw housing 269 downward as shown in FIG. 28. This tends to
urge the jaws 202 into engagement with the pipe 205.
A wiper 272 is provided to remove dirt, grime and other foreign
matter from the surface of the pipe 205. The wiper 272 operates to
prevent dirt and other matter upon the surface of the pipe 205 from
interfering with the gripping surface 204 of the jaws 202.
A releaser, jaw releasing cylinder or cylinder means 273 is
connected to the body 201. The releaser 273 has a rod 274 shown in
FIG. 28 in the retracted position. The rod 274 is operable to be
extended from the releaser 273 so that it contacts the jaw housing
269 and urges it upward. The releaser 273 is adapted to compress
the spring 271 and thus disengage the jaw 202 from the pipe
205.
It will be appreciated that a second similar body 275 may be
stacked with the body 201 to provide more than one set of jaws 202
to grip the pipe 205. The pipe 205 is shown in FIG. 28 with a
casing 276. A second set of jaws provided in the second body 275
would operate to grip the pipe 205 when the casing 276 was passed
through the body 201.
Employed as a safety hanger apparatus, the embodiment of the
invention illustrated in FIG. 28 would permit the drill pipe 205 to
be removed from the hole by moving it upward. However, if the drill
pipe 205 was dropped, the jaws 202 would automatically engage the
drill pie 205 and prevent it from falling into the hole (not
shown). The jaws 202 are adapted to permit the drill pipe 205 to be
moved upwardly in FIG. 28, and are adapted to prevent the drill
pipe 205 from being dropped down the hole or for moving downwardly
in FIG. 28.
It will be appreciated that the embodiment of the invention
illustrated in FIG. 28 may have useful application for other types
of pipe, tubes or cylinders. The present invention is not intended
to be limited to drill pipe.
In the event that it is desired to drill and move the drill pipe
205 downwardly, a similar body 201 may be employed as a blowout
preventer by turning the body 201 upside down from the position
shown in FIG. 28. In such a position, the jaws would permit the
drill pipe 205 to be drilled down into the hole, but would not
allow the drill pipe 205 to be blown out of the hole even in the
event of a sudden increase in downhole pressure. The gripping force
of the jaws 202 upon the drill pipe 205 will be proportional to the
downhole pressure. Thus, the gripping force of the jaws 202 upon
the drill pipe 205 will increase in proportion to any increases in
the downhole pressure. Thus, a great safety feature is achieved by
the present invention because a sudden increase in downhole
pressure will be immediately offset by an increase in the radial
counterforce or gripping force of the jaws 202 upon the drill pipe
205.
The releaser 273 is operable to disengage the jaws 202 when it is
desired to move the drill pipe 205 in a direction opposite to the
direction of movement permitted by the jaws 202.
FIG. 32 depicts an embodiment of the cylinder gripping apparatus
having utility as an offshore drilling platform deck jacking
apparatus.
Although any of the interfacing assemblies previously described
with reference to FIGS. 20 through 31 may be used to interface jaws
with a body, the illustrated embodiment of the platform jacking
apparatus 277 comprises a first jaw 21, a fist arm 22, a first
pivot point 23, a second pivot point 24, a first extension 117, a
first guide or synch sleeve 123, a first shoe or fastening means
119, a first actuation means 121, a first shaft 125 and a first
fastening means 127, as are described more fully with respect to
FIGS. 18 and 19 in the application for a hydrostatic testing
apparatus, Application Ser. No. 037,140, filed May 8, 1979, by the
same applicant, which is incorporated herein by reference.
Similarly, a second jaw 58, second arm 57, third pivot point 60,
fourth pivot point 59, second extension 118, second guide or synch
sleeve 124, second shoe 120, second actuation means 122, second
shaft 126 and second fastening means 128 operate in a manner
similar to the corresponding elements illustrated and described
with reference to FIGS. 18 and 19 of Application Ser. No. 037,140,
filed May 8, 1979, for a hydrostatic testing apparatus, by the same
applicant, which is incorporated herein by reference.
In the embodiment shown in FIG. 32, a third arm 278 is pivotally
connected to the body at a fifth pivot point 279. The third arm 278
is pivotally connected to the first jaw 21 at a sixth pivot point
280. A fourth arm 281 is pivotally connected to the body 290 at an
eighth pivot point 282. The fourth arm 281 is connected to the
second jaw 58 at an eighth pivot point 283. The body 290 is
connected to a platform 284 in the present instance, the platform
284 comprises a conventional offshore drilling platform. The first
and second jaws 21 and 58 comprise a first set of jaws which are
adapted to grip a platform leg 285. A first compression member or
spring 286 is interposed between the first jaw 21 and the body 290.
The spring 286 is adapted to urge the first jaw 21 into engagement
with the platform leg 285. A second compression member or spring
287 similarly urges the second jaw 58 into engagement with the
platform leg 285. A third jaw 288 and a fourth jaw 289 comprise a
second set of jaws adapted to grip the platform leg 285. The second
set of jaws 288 and 289 operate in a manner similar to the first
set of jaws 21 and 58. The body 290 has a guide sleeve 291 which is
adapted to receive a jaw housing 292 which is annularly shaped as
shown in FIG. 32. The jaw housing 292 is adapted to axially receive
the platform leg 285. The body 290 is similarly adapted to axially
receive the platform leg 285. The jaw housing 292 is adapted to
reciprocally slide within the guide sleeve 291 of the body 290.
Actuation means or cylinder means 293 is connected to the body 290.
Actuation means 293 has a shaft 294 which is operable to
reciprocally extend or retract within actuation means 293. The
shaft 294 is connected to the jaw housing 292.
The platform 284 may be jacked up the platform leg 285 by allowing
the second set of jaws 288 and 289 to engage the platform leg 285
while the shafts 294 are in the retracted position. When the shafts
294 are in the retracted position, the jaw housing 292 will be
retracted within the guide sleeve 291 of the body 290. Thus,
cylinder means 293 may be used to extend shafts 294 to push the jaw
housing 292 downwardly with respect to the body 290. Thus, the body
290 and the platform 284 are raised with respect to the platform
leg 285 while the jaw housing 292 remains stationary with respect
to the platform leg 285.
In FIG. 32, the shaft 294 is shown in the fully extended position.
The shaft may be extended a distance X as shown in FIG. 32. Thus,
for each motion, the platform 284 may be jacked up a distance
X.
When the shaft 294 has reached the fully extended position, the
first set of jaws 21 and 58 are allowed to engage the platform leg
285. Thus, the first set of jaws 21 and 58 will hold the platform
284 in position as the shafts 294 and the second set of jaws 288
and 289 are retracted within the guide sleeve 291. It will be
appreciated that both the first set of jaws 21 and 58 and the
second set of jaws 288 and 289 will permit the platform leg 285 to
be moved in one direction with respect to the body 290 and the jaw
housing 292, but will not permit the platform leg 285 to be moved
in an opposite direction with respect to the body 290 or the jaw
housing 292.
The first and second springs 286 and 287 are adapted to insure that
the first set of jaws are urged generally radially inwardly with
sufficient force to insure that the first set of jaws 21 and 58
maintain contact with the platform leg 285. Thus, if the second set
of jaws 288 and 289 should fail for any reason, the first set of
jaws 21 and 58 would automatically grip the platform leg 285 with a
gripping force proportional to the weight of the platform 284 or
proportional to the stresses upon the platform leg 285. Similarly,
a third and fourth spring or compression member 295 and 296 urge
the second set of jaws 288 and 289 into engagement with the
platform leg 285.
In the present instance, a plurality of wipers 297 is provided
between the jaw housing 292 and the guide sleeve 291 and the
platform leg 285. The wipers 297 tend to keep sea water or other
unwanted matter from contaminating the interior of the guide sleeve
291. Air vent ports 298 provide fluid communication between the air
within the interior of the guide sleeve 291 and the external
atmosphere.
A plurality of second wipers 299 is provided between the body 290
and the platform leg 285.
In the illustrated embodiment, the first and third arms 22 and 278
are pivotally connected to a first spline or rib 300 formed from
the body 290. Similarly, the second and fourth arms 57 and 281 may
be pivotally connected to a second spline or rib 301 formed from
the body 290.
The actuation means 121 and 122 may also comprise a first releasor
operable to release the first set of jaws 21 and 58 from engagement
with the platform leg 285. Similarly, actuation means 302 and 304
may comprise a second releasor operable to release the second set
of jaws 288 and 289 from engagement with the platform leg 285. The
second releasor 302 and 304 is operable to disengage the second set
of jaws 288 and 289 to permit the retraction of the jaw housing 292
within the guide sleeve 291.
The platform 284 may be lowered, also by synchronized operation of
first and second releasers 121 and 122, and 302 and 304, in a
manner generally opposite to that described above with reference to
jacking the platform 284 up.
It will be appreciated that the cylinder gripping apparatus
described above may find utility in any application where it is
desirable to grip a cylinder, rod pipe or tube to keep the
cylinder, rod pipe or tube from going in an unwanted direction. The
cylinder gripping apparatus may be employed with utility to hold
the end of a pipe to be forged during the process of upsetting
tubing. Alternatively, the cylinder gripping apparatus may find
utility in holding tubing during the process of belling where a
mandrel is inserted and welded to a pipe or tube. Similarly, any
operation that requires a pipe, tube or cylinder to be held or
gripped where large axial forces tend to urge the pipe, tube or
cylinder in an unwanted direction.
Turning first to FIG. 1, there is shown a partial cutaway view of a
pipe capping apparatus 19 according to the present invention. In a
preferred embodiment, a body 20 and a jaw assembly or jaw 21 are
coupled together with a radial force translator 39. The radial
force translator 39 transforms the axial force exerted upon the
body 20 by a fluid introduced into the interior region 40 of a pipe
26 to a force radially inwardly. The pressure from the fluid is
applied to the body 20 generally in an interior zone 41 within the
body 20. The radial force translator 39 transforms this axial force
into a radially inward force, or a radial counterforce, which is
applied to the outer walls of the pipe 26 by the jaws 21. This
radial counterforce must be sufficient to hold the pipe during
pressurization. Pursuant to the invention, the radial counterforce
is always larger and proportional to the axial force upon the body
20 to assure that the apparatus 19 will not be forced off of the
pipe 26 during pressurization. Thus, when no pressure is exerted
upon the fluid within the pipe 26, little force will be exerted
against the outer surface of the pipe 26 by the jaws 21. As a
safety feature, the greater the pressure upon the inside 40 of the
pipe 26, the greater the gripping force exerted by the jaws 21 upon
the outer surface of the pipe 26.
In a preferred embodiment, the radial force translator 39 comprises
an arm 22 pivotally disposed against or connected to the body 20 at
a first pivot point or pin 23. The arm 22 is also connected to the
jaw 21 at a second pivot point or pin 24. The first pivot point 23
and the second pivot point 24 are adapted to permit the arm 22 to
rotate. Rotation of the arm 22 permits the jaw or jaw assemnbly 21
to move into and out of engagement with the surface of the pipe
26.
The radial translator 39 transforms the axial force into a radial
counterforce proportional to the tangent of a translation angle T.
Different translation angles T may be selected to give the desired
amount of radial counterforce. The translation angle T will depend
upon the length of the arm 22, measured between the first pivot
point 23 and the second pivot point 24, and the distance of the
first and second 23 and 24 from the outer wall of the pipe.
The radial counterfore will always be proportionally related to the
axial pressure force. The axial pressure force will be
substantially equal to the internal fluid pressure multiplied times
the cross-sectional area of the pipe 26. The radial force
translator 39 is operable to produce a radial counterforce applied
by the jaws 21 to the pipe 26 which is proportional to the pressure
multiplied times the cross-sectional area of the pipe 26, all
divided by the tangent of the translation angle T.
It is contemplated that the translation angle T may be an angle
anywhere between 10.degree. and 45.degree.. It has been found that
a preferred embodiment of the radial force translator 39 employs a
translation angle T between 30.degree. and 40.degree.. In the
practice of a preferred embodiment, it has been found that a
translation angle T of 37.degree. provides satisfactory
results.
The translation angle T is determined by a jaw face offset C, a
length of the arm 22 measured between the center of the first pivot
point 23 and the center of the second pivot point 24, and an arm
offset D. In a preferred embodiment, the location of the first
pivot point 23 should be chosen such that it is located in a
tension member 42 of the body 20. The diameter of the pipe 26 to be
tested will also be known.
The strength of the material composing the jaw 21 is important in
determining the jaw face offset C. The pin 24 is preferably located
as close to the pipe 26 as possible consistant with required
clearances and allowable stresses. In a preferred embodiment where
the jaw 21 comprises a single member, the jaw face offset C is
substantially equal to a distance of 2 or 21/2 diameters of a pin
inserted into the second pivot point 24. In a preferred embodiment,
the jaw 21 may be fabricated from steel, or more specifically
heat-treated steel. In the practice of a preferred embodiment, it
has been found that highly ductle carbuerized steel (AISI 1040 or
8620) provides satisfactory results for the jaw tooth segment 47.
The teeth surface should preferably be case hardened to Rockwell
C-50 or C-60.
Generally, it has been found that the allowable shear stress upon
the pin 24, and also the pin 23, should not exceed 25% of the
ultimate yield of the steel composing the pins 24 or 23.
The radial force or clamping force should be greater than the axial
pressure force exerted upon the body 20. The axial force is
substantially equal to the pressure of the fluid in the inner zone
41 of the body 20 times the cross-sectional area of the pipe 26.
The radial force is equal to the axial force divided by the tangent
of the transformation angle T.
Referring to FIG. 1, it is desirable to have the second pivot point
24 located upon the jaw assembly 21 such that the tendency of the
front teeth 92 to bite into the pipe 26 with more force than the
other teeth 92 is minimized. It is desirable to evenly distribute
the radial gripping force exerted by the jaw 21 upon the pipe 26
evenly over the area of the jaw 21 in contact with the surface of
the pipe 26.
In practice, it has been found desirable to place the second pivot
point 24 to the rear of the jaw holder 45 of the jaw assembly 21,
or in the case of a single member jaw 21, to the rear of the jaw
21. This reduces the tendency of the front teeth 92 to bite into
the surface of the pipe 26.
Useful results may be obtained by placing the second pivot point 24
generally in the center of the rear one-half of the jaw 21.
More specifically, in a preferred embodiment, the second pivot
point 24 should be connected to the rear portion of the jaw 21 a
distance F (shown in FIG. 1) from the front of the jaw 21 which is
sufficient to minimize the tendancy of the front teeth 92 to
overbite into the pipe 26 and to mar, deform or leave excessive
teeth imprints in the surface of the pipe 26. In practice, the
second pivot point 24 may be connected a distance F from the front
of the jaw 21 which is equal to the jaw face offset C multiplied
times the crosssection area of the pipe 26 multiplied times the
maximum test pressure that will be desired, all divided by a pipe
stress factor. In practice, a pipe stress factor of 2,000 has been
found to provide satisfactory results. It will be appreciated that
the pipe stress factor may be less than 2,000. This factor is based
upon the amount of pressure that may be exerted by the front teeth
92 of the jaw 21 upon the pipe 26. The pipe stress factor 2,000 is
based upon a permissible radially inwardly force upon the front
teeth 92 and may be defined as 2,000 pounds per inch upon the front
jaw surface circumferentially contacting the surface of the pipe
26. It will be appreciated that the pipe stress factor is a
function of the maximum test pressure desired and the jaw face
offset C.
As discussed above, the jaw face offset C is made as small as
possible consistent with the amount of clearance required to
prevent movement of the jaw 21, and consistent with the allowable
stresses that may be withstood by the jaw 21 such that the pin 24
does not overstress the portion of the jaw 21 between the pin 24
and the pipe 26.
The location of the second pivot point 24 may alternatively be
established where the second pivot point 24 is placed a distance F
from the front of the jaw 21 equal to the jaw face offset C
multiplied times the maximum test pressure desired divided by the
circumference of the pipe 26 to be tested and divided by the force
stress factor. In practice, a force stress factor of 2,000 lbs. per
inch has given satisfactory results.
It is desirable, in locating the second pivot point 24 upon the jaw
21, to minimize the difference between the moments about the center
135 of the friction surface 92 of the jaw 21 in contact with the
pipe 26. Thus, the jaw face offset C times the axial force that
will be axially asserted by the pipe 26 against the teeth 92 at the
pressure to be tested should equal to a load centerline distance E
measured axially between the center 135 of the jaw face 92 and the
second pivot point 24 times the radial force that will be asserted
radially inwardly at the center 135 of the jaw 21 against the pipe
26. Thus, the centerline distance E between the second pivot point
24 and the center of the jaw face 92 should be equal to the jaw
face offset C times the axial force divided by the radial
force.
It will be appreciated that the axial force will be substantially
equal to the cross-sectional area of the pipe 26 times the test
pressure. The radial force substantially equals the axial force
multiplied by the cotangent of the translation angle T. It will be
appreciated that the desired test pressure and the size of the pipe
to be tested will be known.
Referring to FIG. 1, the ratio of the radial force exerted radially
inwardly by the jaw 21 against the pipe 26 to the test pressure
multiplied times the cross-sectional area of the pipe 26, should
equal the ratio of the distance D measured between the first pivot
point 23 and the surface of the pipe 26 minus the jaw face offset C
all divided by the distance M measured axially between the first
pivot point 23 and the second pivot point 24.
It is desirable to have the radial gripping force exterted by the
jaw 21 against the pipe 26 be larger than the axial force tending
to urge the apparatus 19 off of the pipe 26. In a preferred
embodiment, the radial gripping force should range from a force
substantially equal to the axial force, to a force as much as fifty
percent greater than the axial force. In practice, an embodiment
that achieves a radial gripping force substantially equal to one
hundred and thirty-five percent of the axial force has been found
to give satisfactory results. It will be appreciated that the
magnitude of the desirable radial gripping force is related to the
coefficient of friction between the jaw surface 92 and the pipe 26.
The lower the coefficient of the pipe 26 is, the more radial
gripping force required.
The area of the jaw 21 in contact with the surface of the pipe 26
is preferably such that the mechanical pressure per square inch on
the outer wall of the pipe 26 is substantially equal to or larger
than the fluid pressure per square inch on the inner wall of the
pipe 26, as illustrated in FIG. 15. The area of the second jaw 58
is similarly determined.
In practice, satisfactory results have been obtained where the
second pivot point or pin 24 is located one pin diameter below the
top surface of the jaw 21, where the top surface of the jaw 21 is
the surface generally opposite the friction surface 92.
Satisfactory results have been obtained where the second pivot
point 24 is located one and a half to three pin diameters from the
rear of the jaw 21; however, the distance to the rear (or to the
right of pin 24 in FIG. 1) of the jaw 21 is not significantly
important. The important feature in locating pin 24 is how far the
pin 24 is located from the front of the jaw 24.
The body 20 has a tension member 42 formed at the rear zone or rear
of the body 20, shown in FIG. 1 as the region 130 to the right of
the broken line R-R. The first pivot point 23 is located to the
rear 130 of the body 20 such that the first pivot point 23 is
located radially in line with the tension member 42. This
arrangement of the first pivot point 23 and the tension member 42
provides a superior advantage in the force bearing properties of
the body 20.
When pressurized fluid is introduced into the interior zone 40 of
the pipe 26, the apparatus 19 is urged off of the pipe 26, or to
the left in FIG. 1. This urging force is transmitted through the
radial force translator and tends to urge the first pivot point 23
radially outwardly. The tension member 42 comprises a member or
plate having an aperture 43 adapted to receive the pipe 26. The
tension member 42 bears the tension force created by the first
pivot point 23 and bears the stress that would otherwise be
transmitted to the front of the body and greatly magnified by the
leverage action of a side 44 of the body 20.
Without the tension member 42, the first pivot point 23 would urge
radially outwardly upon the side 44. The side 44 would act like a
lever to magnify the strength of this force upon the front of the
body 20. Under high pressure testing, the force upon the rib shown
in the earlier patent 4,077,250 could be great enough to fracture
the body 20, resulting in the destruction of the hydrostatic
testing apparatus. Without the tension member 42, a large and
relatively expensive side 44 of the body 20 would be required to
withstand high pressure testing.
In a preferred embodiment, the body 20 is formed or joined
integrally with the tension member 42 such that the body 20 is
formed into a one piece member including the tension member 42 and
the side 44. The tension member 42 redistributes the stress created
by the force exerted upon the first pivot point 23. This force is
born directly in tension by the tension member 42. This results in
a more practical, and more economically constructed,
embodiment.
In an alternative embodiment, the tension member 42 may comprise a
separate plate securely fastened to the body. In such an
embodiment, the tension plate 42 should have overlapping lips or a
collet located radially outwardly from the body 20 to hold the side
44 of the body 20 radially inwardly if the first pivot point 23 is
located in the body 20. Conventional fastening means could be used
to attach the plate 42 to the body 20.
It is desirable to permit the same testing apparatus 19 to test a
variety of pipe sizes. It is also desirable to permit the apparatus
19 to test a pipe 26 with an upset, bell end or coupling end. The
pipe receiving aperture 43 must be large enough to pass the upset,
bell end or coupling. Thus, some means is required to axially
center the pipe 26 within the body 20.
Referring to FIG. 1, a centralizer 27 is connected to the rear of
the body 20 at the tension plate 42. The centralizer 27 is adapted
to axially center the pipe 26 to be hydrostatically tested. The
centralizer 27 comprises a plurality of rotatable cam levers or
cantilevered arms 28. The cam levers 28 have a cam piece 32 adapted
to urge the pipe 26 into an axially centered position within the
pipe receiving zone or aperture 43 of the body 20 or the tension
member 42. The cam lever 28 is joined to the cam piece 32 by
fastening means 33 comprising a bolt, screw or a pin. In a
preferred embodiment, fastening means 33 is adapted to permit
removal of the cam piece 32. Therefore, the cam piece 32 may be
changed for various sizes of pipe in order to permit the
adaptability of the centralizer 27 to varying outside diameters of
pipe.
The cam lever 28 is rotatably attached to the tension member 42 by
fastening means 30 and 29. Fastening means 30 may comprise a screw
or bolt and fastening means 29 may comprise a cylinder or a
pin.
The cam lever 28 may comprise a cantilevered arm 31 pivotally
attached to the body 20 by means of a pivot cylinder 29 fastened to
the body 20 with a bolt 30. The cam lever 28 has a drive surface
34. The drive surface 34 is adapted to permit the engagement of
drive means 35, thereby permitting synchronized mechanical
communication between the cantilevered arms or cam levers 28. It
will be appreciated that drive means 35 may be unsynchronized.
In a preferred embodiment, the drive means 35 may comprise a belt
engaging a pully surface 34. In an alternative embodiment, the
drive means 35 may comprise a chain engaging teeth or sprockets 34.
In yet another embodiment, the drive means 35 may comprise a
gearing arrangement. It will be appreciated that hydraulic means
may also be used to actuate the cantilevered arms 28.
Referring to FIG. 2, the centralizer is shown in an open position.
Actuation means 36 is shown connected to a first cam arm pivot
point 38. The cantilevered arms 28 are mechanically coupled to the
handle 36 through the drive means 35 engaging the drive surface 34
of the cam levers or arms 28.
In FIG. 2, the pipe 26 is shown in an off-center position.
The interchangeable cam pieces 32 have a cam surface 37.
Alternatively, the cantilevered arms or cam levers 28 may be formed
into one piece without the interchangeable cam pieces 32.
As shown in FIG. 3, when the handle 36 is rotated about the first
cam lever pivot point 38, the cam levers or cantilevered arms 28
are rotated by the drive means 35. Rotation of the cantilevered
arms 28 causes the pipe 26 to contact one or more of the cam
surfaces 37. The cam surfaces 37 are adapted to urge or cam the
pipe 26 into an axially centered position. Thus, the centralizer 27
is adapted to axially center the pipe 26 using a single motion or
movement.
It will be appreciated that the cantilevered arms 28 may be
independently operated in order to center the pipe 26. In a
preferred embodiment, the cantilevered arms 28 operate
simultaneously and are equiangularly disposed about the pipe
receiving zone 43 of the body 20.
The jaw assembly 21, illustrated in FIG. 1, comprises a jaw holder
45, a fastening means 46, a jaw tooth segment 47, and an alignment
key 48. Fastening means 46 may be a bolt, screw, pin or other
mechanism adapted to fasten the jaw holder 45 to the jaw tooth
segment 47.
The jaw holder 45 has a load recess 49. The jaw tooth segment 47
has a load protuberance 50. The load recess 49 is adapted to
receive the load protuberance 50. During pressurization of the pipe
26, a shear force develops against the load protuberance 50 which
is inserted within the load recess 49. The load protuberance 50 is
adapted to withstand the shear force exerted upon it by the jaw
holder 45 at a load interface 131. The load protuberance 50 may
comprise steel lugs, and in practice heat heated steel lugs have
provided satisfactory results. The load protuberance 50 and the jaw
holder 49 permit the jaw tooth segment 47 to be held securely by
the jaw holder 45 and inhibit the jaw tooth segment 47 from sliding
axially against the jaw holder 45.
The jaw holder 45 has a jaw segment receiving face 52. A first key
way slot 53 is located on the jaw segment receiving face 52. The
jaw tooth segment 47 has a face adapted to abut against the jaw
segment-receiving face 52 of the jaw holder 45. The jaw tooth
segment 47 has a second key way slot 51. The second key way slot 51
is adapted to align with the first key way slot 53 such that when a
alignment key 48 is inserted therein the jaw tooth segment 47 is
properly aligned with the jaw holder 45.
In a preferred embodiment, the contiguous faces of the jaw holder
45 and the jaw tooth segment 47 are congruent. It will be
appreciated that the jaw 21 may alternatively be constructed as a
one piece embodiment.
In the illustrated embodiment having two arms 22 and 57 shown in
FIG. 1, the first arm 22 has a first spring-fastening extension or
spring anchor 54 joined to it near the second pivot point 24. This
spring-fastening extension 54 has connected to it one end of an
elastic member, resilient member or spring 55.
The spring 55 has its other end connected to a second
spring-fastening extension or spring anchor 56. The first
spring-fastening extension 54 and the second spring-fastening
extension 56 are offset from the axis A of the body 20 in order
that the elastic member 55 may be extended therebetween without
interfering with the axial placement of the pipe 26. The second
spring-fastening extension 56 is joined or connected to a second
arm 57. The second arm 57 is connected to a second jaw or jaw
assembly 58 at a fourth pivot point 59. The second arm 57 is
connected to the body 20 at a third pivot point 60. Thus, a second
radial force translator 61 comprises the second arm 57, the third
pivot point 60, the fourth pivot point 59 and the second jaw 58.
The operation of the second arm 57, the third pivot point 60, the
fourth pivot point 59 and the second jaw 58 is similar to the
operation of the first arm 22, the first pivot point 23, the second
pivot point 24 and the first jaw 21, respectively.
The elastic member 55 is adapted to urge the first arm 22 and the
second arm 57 radially inwardly. When the pipe 26 is actually
inserted into the body 20, the elastic member 55 urges the first
jaw 21 and the second jaw 58 into engagement with the pipe 26. In a
preferred embodiment, the elastic member 55 is adapted to urge the
jaws 21 and 58 to exert a pressure of substantially 15 psi upon the
outer surface of the pipe 26. The elastic member 55 is used to
initially urge the jaws 21 and 58 into contact with the pipe 26.
Once engaged, the force upon the jaws 21 and 58 will increase in
proportion to the pressure asserted upon the interior zone 41 of
the body 20, which is translated to the jaws 21 and 58 through the
first radial translator 39 and the second radial translator 61,
respectively.
It will be appreciated that the elastic member 55 may be replaced
by equivalent means adapted to urge the jaws radially inwardly. For
example, a spring may be placed between the first arm 22 and the
inner surface of the body 20, which is compressed when the first
jaw 21 is urged radially outardly, thus providing a counterforce
urging the first jaw 21 radially inwardly. A similar spring could
be provided for each jaw or arm.
Many pipes that require testing have threads and couplings upn
their ends. Many prior art devices can damage pipe threads during
use. To faciliate the insertion and removal of the pipe 26, a first
bumper 62, a second bumper 63 and a third bumper 64 are provided in
a preferred embodiment of my invention, as shown in FIG. 1. In a
preferred embodiment, the first bumper 62, the second bumper 63 and
the third bumper 64 are elastomer members or bumpers. The first
bumper 62 protects the pipe threads upon initial insertion of the
pipe 26 into the centralizer 27 and the pipe receiving zone 43 of
the body 20.
The second bumper 63 protects the threads of the pipe 26 upon
insertion of the end of the pipe 26 into the interior zone 41 of
the body 20. The third bumper 64 is adapted to permit the initial
abutment of the end of the pipe 26 against the inner surface of the
body 20. During hydrostatic pressure testing, the pipe 26 will be
urged away from the elastomer bumper 64 by the fluid pressure upon
the interior 40 of the pipe 26 and the interior zone 41 of the body
20. However, actual tests have shown that little or no actual
movement is observable. To facilitate fluid communication between
the interior zone 41 of the body 20 and the passageway 72, a notch
64 is provided in the bumper 73.
It is desirable to have a hydrostatic testing apparatus capable of
testing pipe of varying diameters. Moreover, it is desirable to
have a hydrostatic testing apparatus adapted to receive upset
tubing or couplings.
An adaptor 66 and a threaded seal nut 65 are removably engagable
within the front portion of the body 20, as shown in FIG. 1. The
adaptor 66 and the seal nut 65 contain are used to provide a
pressure tight seal for several different pipe sizes as desired. It
will be appreciated that when only one size of plain end pipe 26,
is to be tested, the adapter 66 is unnecessary and the seal nut 65
is screwed directly into the body 20.
In a preferred embodiment, the adaptor 66 is threadably engaged
within the rear portion of the body 20. Thus, the adaptor 66 may be
screwed into the body 20 to permit the adaptor 66 to be inserted or
removed when required. The seal nut 65 is threadably engaged or
screwed into the adaptor 66. The second elastomer bumper 63 is
molded upon or adhesively affixed to the seal nut 65.
During hydrostatic testing of the pipe 26, it is desirable to
introduce fluid, usually water, into the interior 40 of the pipe 26
and into the interior zone 41 of the body 20. Referring to FIG. 1,
an axial passage, tube, opening or aperture 67 is shown generally
axially centered within the rear of the body 20. In a preferred
embodiment, threads are provided upon the interior of the axial
passage 67 to permit the attachment of a pipe or a tube 68 to the
body 20.
The axial passage 67 is in fluid communication with the interior
zone 41 of the body 20 and the interior 40 of the pipe 26.
During the hydrostatic testing of the pipe 26 at high pressure
levels, it is important to remove all air or other gas from the
interior 40 of the pipe 26, and from the interior zone 41 of the
body 20. Failure to remove all of the air may create a hazard of
explosion. High pressure hydrostatic testing may be hazardous and
unsafe unless substantially all of the air or gas is removed from
the interior 40 of the pipe 26.
Referring to FIG. 1, the hydrostatic testing apparatus includes a
feature comprising an air purge valve 69. The purge valve 69
comprises a control port 70 joined or secured to a stem 71. A
passageway 72 joins the purge valve 69 to the interior zone 41 of
the body 20. The passageway 72 is adapted to place the purge valve
69 in fluid communication with the interior zone 41. In a preferred
embodiment, the purge valve 69 is vertically connected to the body
20. The stem 71 is placed in fluid communication with the highest
point of the interior zone 41 of the body 20. Thus, as air bubbles
normally accummulate at the highest portion of the interior zone 41
of the body 20, these air bubbles may be removed by opening the
control port 70.
In a preferred embodiment, fluid is introduced into the axial
passageway 67 from a fluid source having check valves of a
conventional type, thus filling the interior zone 41 of the body 20
and the interior 40 of the pipe 26. It will be appreciated that
filling may be effected from the opposite end of the pipe 26.
During filling, the purge valve 69 is opened by means of the
control port 70. Air present in the interior zone 41 of the body 20
wil be urged upward by the fluid introduced into the interior zone
41, and the air within the pipe would thus be urged up through the
stem 71 and out the control port 70. The mixture of fluid and air
exiting through an orifice in the control port 70 will normally be
visually observable as a sputtering mixture of fluid and gas. When
the sputtering stops and a solid stream of fluid or water begins to
emerge from the purge valve 69, the purge valve 69 may be closed by
means of the control port 70. Thus, the purge valve 69 is adapted
to safely expunge substantially all the air or gas within the
region 41 of the body 20 and the interior 40 of the pipe 26.
The pipe 26 will preferably not be in fluid-tight engagement with
the third bumper 64. In a preferred embodiment, a notch, slot or
second passageway 73 is provided in the third bumper 64 to
facilitate fluid communication between the interior zone 41 of the
body 20 and the passageway 72.
It is desirable during pressurization to provide a sealtight
engagement between the body 20 and the pipe 26. When the adaptor 66
and the seal nut 65 are inserted within the body 20, it is
desirable to provide a fluid-tight seal or a pressure barrier
between the pipe 26 and the adaptor 66.
Referring to FIG. 1, a first pressure barrier apparatus 75 and a
second pressure barrier apparatus 74 are shown.
The first pressure barrier apparatus 75 may be a flexible member or
seal. The second pressure barrier apparatus 74 is similarly
constructed.
The seal nut 65 is adapted to hold the first seal 75 in place as
shown in FIG. 1. The seal nut 65 permits the seal 75 to be easily
replaced, if desired. If the adapter 66 is not used, only one seal
74 will be required.
The pressure barrier apparatus 75 and 74 is depicted in greater
detail in FIG. 7. As may be seen in FIG. 7, the pressure barrier
apparatus 75 comprises a first lip 76 and a second lip 77 connected
to a body 78. The pressure barrier apparatus 75 is a flexible
member and is adapted to permit the flexible movement of the first
lip 76 and the second lip 77. The first lip 76 and the second lip
77 are adapted to spreadably engaged a first surface 89 of the body
20 and a second surface 90 of the pipe 26, respectively, thereby
defining an inner zone 83 and an outer zone 82 (see FIG. 8) when
the first and second lips 76 and 77 are urged respectively against
the first and second surfaces 89 and 90 during pressurization.
The operation of the seals 74 and 75 when an adapter 66 is employed
is equivalent. A first lip 76 of the pressure barrier apparatus 74
contacts a first surface of the body 20 and a second lip 77
contacts a second surface of the adapter 66. Similarly, a first and
second lip 76 and 77 of the first apparatus 75 contact a first and
second surface of the adapter 66 and the pipe 26, respectively.
Referring to FIG. 7, the first lip 76 and the second lip 77 define
a pressure zone 79. During pressurization, fluid is introduced into
the fluid pressure zone 79, thus urging the first lip 76 and the
second lip 77 apart. The first lip 76 is adapted to displace or
dispose toward the inner surface of the body 20. The second lip 77
is adapted to displace toward the outer surface of the pipe 26.
A front view of the flexible member 75 is shown in FIG. 6. A
plurality of lugs 80 are shown formed upon the second lip 77. The
lugs 80 define interstices 81. The interstices 81 are in fluid
communications with the pressure zone 79. The interstices 81 are
also in fluid communication with the passageway 72.
It will be appreciated that the lugs 80 may also be formed upon the
first lip 76.
As depicted in FIG. 8, the flexible member 75 is adapted so that
the first lip 76 disposes against the inner surface of the body 20.
The second lug 77 is adapted to displace toward the outer surface
of the pipe 26. The flexible member thus defines an inner zone 83
and an outer zone 82. The inner zone 83 is filled with fluid during
pressurization. The flexible member 75 thus forms a pressure
barrier between the inner zone 83 and the outer zone 82.
Preferably, the second lip 77 is relatively long in order to
provide a large area of engagement with the surface of the pipe 26
to facilitate a fluid-tight seal where the surface of the pipe 26
is rough, rusty or dirty.
It is desirable to pre-stress the second lip 77 so that the second
lip 77 is urged into engagement with the outer surface of the pipe
26. This is accomplished by the lug 80. The lug 80 has a length
measured radially sufficient to urge the second lip 77 into
engagement with the outer surface of the pipe 26. Thus, when little
or no pressure is applied to the inner zone 83, the lug 80 urges
the second lip 77 into sealing engagement with the outer surface of
the pipe 26 and inhibits leakage of fluid into the outer zone
82.
The interstices 81 place the pressure zone 79 into fluid
communication with the inner zone 83. The inner zone 83 is in fluid
communication with the passageway 72. Introduction of fluid into
the interior zone 41 of the body 20 (shown in FIG. 1) permits fluid
to enter the passageway 72 and the inner zone 83 illustrated in
FIG. 8. The interstices 81 permit fluid to enter the pressure zone
79. Pressurization of the fluid thus urges the second lip 77 into
engagement with the outer surface of the pipe 26.
Flushing of the pressure zone 79 is desirable to effect the removal
of dirt, rust, debris and other matter that may accummulate within
the pressure zone 79. Thus the lugs 80 facilitate the flow of
liquid through the pressure zone 79 and thereby permit the pressure
zone 79 to be flushed by the fluid. The pressurization and
depressurization of the fluid thus flushes out the pressure zone 79
and tends to remove dirt, debris and other foreign matter that may
otherwise accummulate within the pressure zone 79.
It is also desirable to remove substantially all air trapped within
the pressure zone 79 of the flexible member 75 to reduce the hazard
of explosion. The lugs 80 also 75 to reduce the hazard of
explosion. The lugs 80 also facilitate the removal of air from the
pressure zone 79. Referring to FIG. 1, the purge valve 69 is placed
into fluid communication with the pressure zone 79 defined by the
flexible member 74. In a preferred embodiment, the stem 71 of the
purge valve 69 is positioned adjacent the pressure zone 79 at the
highest point of the pressure zone 79 within the body 20. Thus, the
purge valve 69 also facilitates the removal of air or other gas
from the pressure zone 79. This further reduces the hazard of
explosion that could result if air remained within the hydrostatic
testing apparatus 19.
FIG. 1 shows a cross sectional view of the seal or pressure barrier
apparatus 74 or 75. It is contemplated that the seals 74 and 75
will be formed into circular rings. However, the seals 74 and 75
may be any shape depending upon the shape of the contiguous
surfaces of the body 20, the pipe 26, and the adapters 66 and
65.
Referring to FIG. 9, an alternative embodiment of the pressure
barrier apparatus is shown which is suitable for relatively high
pressure hydrostatic testing. The pressure barrier apparatus 75
comprises a flexible member 88 having a first lip 76 and a second
lip 77 joined to a body, and a spacer 84 and a sealing ring 85. The
flexible member 88 is constructed similarly to the flexible member
described with reference to the embodiment of the pressure barrier
apparatus 75 depicted in FIG. 6, FIG. 7 and FIG. 8.
The first lip 76 is disposed against a first surface 89 of the body
20. The second lip 77 is adapted to engage a second surface 90 of
the pipe 26. The lug 80 urges the second lip 77 radially inwardly
toward the second surface 90, and also forms interstices, as shown
in FIG. 6, permitting fluid communication between the pressure zone
79 and the inner zone 83.
Referring to FIG. 9 the spacer 84 is located radially rearwardly of
the flexible member 88. The sealing ring 85 is located rearwardly
of the spacer 84. Thus, the spacer 84 is interposed between the
flexible member 88 and the ring 85. The spacer 84 permits the
flexible member 88 and the ring 85 to reciprocally slide against
each other in a generally radial direction.
The ring 85 is preferably made of metal. The ring 85 may be made of
steel, as in a preferred embodiment; but it is also contemplated
that the ring 85 may be fashioned from beryllium copper or
aluminum.
The ring 85 rests against a sloped or cam surface 87 of the body
20. If an adaptor 66 is utilized, the cam surface 87 will be in the
adapter 66. The body 20 also has an indentation or groove forming a
spacer stop gap 86, best shown in FIG. 9A. When little or no
pressure is applied to the inner zone 83, the ring 85 will normally
rest generally in the position shown in FIG. 9.
During hydrostatic testing, pressurized fluid is introduced into
the passageway 72, the inner zone 83, and the pressure zone 79, as
shown in FIG. 10. Relatively high pressures could cause the
flexible member 88 to extrude into the space between the body 20
and the pipe 26, generally shown in FIG. 9 as outer zone 82.
As best shown in FIG. 10, during pressurization the flexible member
88 is urged generally axially reawardly. The flexible member 88
urges the spacer 84 axially rearwardly. The spacer 84 thus urges
the ring 85 axially rearwardly and causes the ring 85 to slide
rearwardly along the sloped or cammed surface 87 of the body 20.
The sloped surface 87 causes the ring 85 to contract radially
inwardly and tend toward the outer surface 90 of the pipe 26.
If the pressure is sufficiently high and if the size of the pipe 26
permits, the spacer 84 will slide radially rearwardly until it
occupies the spacer stop gap 86 in the position shown in FIG. 10A.
The flexible member 88 and the spacer 84 move axially rearwardly.
The flexible member 88 and the spacer 84 urge the ring 85 axially
rearwardly and radially inwardly as it slides along surface 87 of
the body 20. Preferably, the ring 85 should be urged into contact
with the surface 90 of the pipe 26. As shown in FIG. 10, the ring
85 inhibits the extrusion of the flexible member 88 during
relatively high pressure testing.
As shown in FIG. 10B, some extrusion of the flexible member 88 may
occur within the zone between the spacer 84 and the pipe 26. This
amount of extrusion is normally acceptable.
FIG. 11 shows a front cross sectional view of the ring 85 taken
along section line 11--11 in FIG. 9. The ring 85 may be a resilient
ring having an expansion gap 91 between the ends thereof. FIG. 11
corresponds to the unpressurized or low pressure position of the
ring 85 shown in FIG. 9.
FIG. 12 shows the ring 85 during high pressure testing in a
position that corresponds to the relative position of the ring 85
shown in FIG. 10 during the pressurization. Preferably, the ends of
the ring 85 may come into contact during pressurization.
FIG. 13 shows an alternative embodiment of the ring 85 having
slanted ends forming an expansion of gap 91. As shown in FIG. 14,
the ends of the ring 85 may come into contact during relatively
high pressurization.
It will be appreciated that the effective diameter of the ring 85
is larger when the ring 85 is in the position shown in FIG. 9, as
compared to the diameter of the ring 85 when it is in the position
shown in FIG. 10. The embodiments of the ring illustrated in FIGS.
11 through 14 illustrate how the ring 85 is permitted to expand to
the position shown in FIG. 9. It will be appreciated that the
embodiment disclosed in FIGS. 13 and 14 permits contraction of the
diameter of the ring 85 even after the ends of the ring 85 have
come into contact in the position shown in FIG. 14. The slanted
ends of the ring 85 may continue to slide against each other and
permit continued contraction of the diameter of the ring 85 if
necessary.
The pressure barrier apparatus 75 and in FIGS. 6, 7 and 8, and the
flexible member 88 shown in FIGS. 9 and 10, may be constructed
similarly. The flexible member 88 may be formed from polyurethane,
commonly referred to as urethane. Fine powered molybdenum disulfide
is cast with the polyurethane during the fabrication process. The
molybdenum disulfied facilitates lubricity between the flexible
member 88 and the pipes 26 which are normally repeatedly inserted
into and removed from the body 20 during testing. Preferably, the
flexible member 88 comprises a polyurethane ester base material,
but it is contemplated that an ether base polyurethane may also be
used. As ester base material has good properties with respect to an
environment involving a substantial exposure to water.
In a preferred embodiment, the flexible member 88 comprises a
polyurethane, ester base, 85 durometer (shore A) seal cast with
fine powered molybdenum disulfide. The flexible member 88 may be
diamine cured.
As best shown in FIG. 7, the lips 76 and 77 should be relatively
long as compared to the length, measured axially, of the member
body 78. In a preferred embodiment, the second lip 77 is
substantially twice as long as the length measured axially of the
member body 78. Preferably, the first lip 76 may be longer than the
second lip 77, facilitating fluid communication between the inner
zone 83 and the passageway 72. The first lip 77 length may be
preferably determined by multiplying the thickness, measured
radially, of the member body 78 by a factor of two or more.
Preferably, the second lip 77 should be substantially thicker than
the first lip 76. In practice, a second lip 77 substantially twice
as thick as the first lip 76 has provided satisfactory results.
This construction is adapted to enhance the relative abrasion
resistivity of the second lip 77 to increase its ability to
withstand wear, thus reducing the incidence of replacement of the
seal 75.
Preferably, the flexible member 88 should be fabricated from a
material having a high compressive strength that is tear resistant
and abrasive resistant. Alternative materials that may be used
include rubber or elastomer, in addition to polyurethane.
Illustrated in FIGS. 4 and 5 is an alternative embodiment of the
jaw 21.
Referring to FIG. 5, the jaw 21 is connected to an arm 22 at a
second pivot point 24. The arm 22 comprises a first link 93 and a
second link 94, as shown in FIG. 4. It has been found that links 93
and 94 provide a superior embodiment for the arm 22. The dual links
93 and 94 yield an arm 22 having superior structural features over
a single link arm. The dual links 93 and 94, among other things,
permit the jaw 21 to be pivotally connected to the body 20 in a
more stable configuration. Actual tests have proven the superior
stability of the dual links 93 and 94 embodiment of the arm 22. The
dual links 93 and 94 also permit the construction of a practical
hydrostatic testing apparatus 19 having only two jaws 21.
Referring to FIG. 5, the jaw 21 comprises a jaw holder 95 and a jaw
tooth segment 96, pivotally connected with a pin 97.
The jaw tooth segment 96 has a friction surface 92 shown in FIG. 4
which is adapted for gripping the pipe 26. In a preferred
embodiment using two jaws 21 for gripping the pipe 26, the friction
surface 92 of the jaw tooth segment 96 is adapted to grip
substantially half of the circumference of the pipe 26. Preferably,
the distance "X" shown in FIG. 4 is substantially 1/2 inch. Thus,
it will be appreciated that approximately all but one inch of the
pipe 26 circumference is gripped by the two jaws 21.
The jaw holder 95 has a load recess 98. The jaw tooth segment 96
has a corresponding load protuberance or load lug 99. During
pressurization, the jaw tooth segment 96 will be urged generally
axially rearwardly. Thus, a generally axial shear force will be
borne by the load protuberance 99 at the load interface 100.
As shown in FIG. 5, the load protuberance 99 is in a generally
axially forward position with respect to the jaw holder 95. This
enhances the shear force bearing properties of the jaw holder 95.
It will be appreciated that the load protuberance 99 may comprise
one or more lugs fashioned from steel, or some other material
having an ultimate yield sufficient to withstand the shear force
that will be developed across the load interface 100 as a result of
pressurization. The required ultimate yield of the material will
depend upon the maximum test pressure that will be applied to the
pipe 26.
Because the load protuberance 99 and the load interface 100 located
in the load recess 98 bears the load, the pin 97 does not bear a
significant portion of the load. As shown in FIG. 4, the jaw holder
95 has a first boss ledge 101 and a second boss ledge 102. The jaw
holder 95 has a corresponding first channel 103 and a second
channel 104. The first channel 103 is adapted to receive the first
boss ledge 101. Similarly, the second channel 104 is adapted to
receive the second boss ledge 102. As shown in FIG. 4, the radially
inward force exerted by the jaw holder 95 upon the jaw tooth
segment 96 is substantially borne at the interfacing surfaces
between the first and second channels 103 and 104 and the first and
second boss ledges 101 and 102, respectively.
The pin 97 is inserted axially into a pin-receiving aperture 105 in
the jaw holder 95.
It is desirable to permit movement of the jaw tooth segment 96
radially to facilitate the engagement of the first and second
channel 103 and 104 with the first and second boss ledges 101 and
102. Thus, as shown in FIG. 4, the pin receiving aperture 105, in a
preferred embodiment, has a generally eliptical cross sectional
area. The pin receiving aperture 105 forms a slot which permits the
pin 97 to move radially outward until the first and second channels
103 and 104 engage the first and second boss ledges 101 and
102.
The jaw tooth segment 96 has a pin-receiving aperture or channel
106 extending through the upper portion of the jaw tooth segment 96
generally parallel to the axis of the body 20 or the pipe 26. The
pin receiving aperture 106 has a generally circular cross sectional
area, in a preferred embodiment. The pin receiving aperture 106 may
be any shape which conforms to the shape of the pin 97.
As shown in FIG. 5, the pin 97 seats in the pin receiving aperture
106. It will be appreciated that movement of the pin 97 within the
pin receiving slot 105 permits the jaw tooth segment 96 to move
generally radially with respect to the pipe 26, thus permitting the
first and second boss ledges 101 and 102 to seat within the first
and second channels 103 and 104. The pin 97 is held in place by
keepers, or washers 107.
It is desirable to evenly distribute the generally radially inward
force exerted upon the jaw tooth segment 96 by the jaw holder 95
evenly across the outer surface of the pipe 26. The generally
parallel alignment of the pin 97, the pin receiving aperture 106,
and the pin receiving slot 105 permits the jaw tooth segment 96 to
evenly engage the pipe 26. A shown in FIG. 4, the jaw tooth segment
96 is adapted to evenly distribute the radially inward gripping
force across the outer surface of the pipe 26.
It will be appreciated that the embodiment of the jaw assembly 21
illustrated in FIGS. 4 and 5 does not require a pin 97 of
sufficient strength to withstand the forces described above. This
embodiment does not require large shear forces to be withstood by
the pin 97 and is therefore more advantageous in this respect.
Referring to FIG. 1, it will be appreciated that the jaw assembly
21 may be a single piece, as is illustrated in the embodiment shown
in FIG. 4 and FIG. 5, or in FIG. 15.
It will be appreciated that the second pivot point shown in FIG. 4
and FIG. 5 may comprise a pin 24 held in place by keepers 108.
Referring to FIG. 1, the first, second, third and fourth pivot
points 23, 24, 60, and 59 may be similarly constructed.
FIG. 15 illustrates an alternative embodiment of the jaw assembly
21. In the illustrated embodiment, the jaw assembly 21 comprises a
single piece jaw 21 having a friction surface 92. Dual links 93 and
94 connect the jaw 21 to the body 20. The jaw 21 is pivotally
connected to the dual links 93 and 94 at a second pivot point 24.
The dual links 93 and 94 are substantially parallel to each other
in a plane transversing the axis A of the body 20.
In a preferred embodiment, the friction surface 92 shown in FIGS.
1, 4 and 15 may comprise teeth or serrations for the purpose of
increasing the coefficient of friction of the friction surface 92.
It has been found that teeth may be required if the surface of the
pipe 26 is dirty. The translation angle T may be adjusted to reduce
the radial gripping force exerted by the jaw assembly 21 upon the
pipe 26 if necessary to avoid damage to the pipe 26 by the teeth
92. If the pipe 26 is smooth, then the friction surface 92 may
comprises grooves or fine serrations. It will be appreciated by
those skilled in the art that other surfaces may be employed as a
friction surface 92 with some degree of utility.
FIG. 16 illustrates an alternative embodiment of a hydrostatic
testing apparatus 19 illustrating an alternative means for grasping
the pipe 26. It will be appreciated that the means for grasping the
pipe 26 illustrated in FIG. 16 may be employed with utility in
other applications where it is desirable to grasp a round or
tubular cylinder. The grasping means comprises a first arm or link
22 pivotally connected to the body 20 at a first pivot point 23.
The first arm 22 is pivotally connected to a first jaw 21 at a
second pivot point 24. A second arm 57 is pivotally connected to a
generally opposite side of the body 20 at a third pivot point 60.
The second arm 57 is pivotally connected to a second jaw 58 at a
fourth pivot point 59.
A wheel or cam 112 is eccentrically rotatably connected to the
second pivot point 24. The wheel 112 has an outer bearing surface
113.
The second arm 57 has an extension, projection, finger or leg 111
extending from the radially inward end of the second arm 57 near
the second pivot point 59. In a preferred embodiment, the extension
111 projects from the second arm 57 at an angle generally
perpendicular to the axis of the body 20 when the jaws 21 and 58
are engaged against the surface of the pipe 26.
The extension 111 has a cam roller 114 attached to the tip of the
extension 111 as shown in FIG. 16. The roller 114 is rotatably
mounted to the end of the extension 111.
An elastic member or spring 110 is connected to the end of the
extension 111 and to the first arm 22. It will be appreciated that
the spring 110 may be connected in any manner which will tend to
urge the first arm 22 and the second arm 57 axially inwardly. The
elastic member 110 tends to urge the first and second jaws 21 and
58 into initial engagement with the tubular cylinder 26.
Referring to FIG. 17, when the wheel 112 is rotated in a first
sense, which is ia counterclockwise direction in the embodiment
illustrated in FIGS. 16 and 17, the bearing surface 113 of the
wheel 112 contacts the roller 114 of the extension 111 and urges
the first and second jaws 21 and 58 radially outwardly. If only one
of the jaws 21 and 58 disengages the pipe 26, the jaw disengaged 21
or 58 will be caused to contact the inner surface 109 of the body
20 by rotation of the wheel 112. Further rotation of the wheel 112
will then urge the other jaw 21 or 58 to disengage the pipe 26.
The elastic member 110 is adapted to urge the first and second arms
22 and 57 radially inwardly and thus urge the wheel 112 in a
rotational sense opposite the first sense, or clockwise in FIGS. 16
and 17.
Actuation means 115 is provided to initiate the rotation of the
wheel 112. In a preferred embodiment, actuation means 115 may
comprise a handle 115 as shown in FIGS. 16 and 17. It will be
appreciated that rotation of the wheel 112 may be actuated by
conventional means.
FIG. 16 also illustrates an embodiment of the body 20 showing a
flange 116 fashioned upon a front face of the body 20. The flang
116 can be made integrally with the body 20 to permit a weldless
flanged connection to be made to a plain end pipe. With the
illustrated embodiment, two testing apparatus 19 may be placed
front to front for adjoining to plain end pipes where welding is
not available as, for example, in a hazardous area.
Illustrated in FIG. 18 and FIG. 19 is an alternative embodiment of
a means for engaging and disengaging the jaws 21 and 58 upon the
outer surface of the pipe 26. A first arm 22 is pivotally connected
to the body 20 at a first pivot point 23. A second arm 57 is
pivotally connected to a generally opposite side of the body 20 at
a third pivot point 60. The first and second arms 22 and 57 are
pivotally connected to a first and second jaw 21 and 58 at a second
and fourth pivot point 24 and 59, respectively, in a manner similar
to that described with reference to the embodiment illustrated in
FIGS. 16 and 17.
The first arm 22 has an extension, offshoot or appendage 117. The
second arm 57 has a similar second extension 118. The first and
second extensions 119 and 118 are connected to the first and second
arms 22 and 57 near the end of the arms 22 and 57 attached to the
body 20.
The first extension 117 is connected to a first guide sleeve or
such sleeve 123 at a shoe or fastening means 119. The second
extension 118 is similarly connected to a second guide sleeve or
synch sleeve 124 at a second shoe or fastening means 120. A first
and second actuation means 121 and 122 are connected to the body
20. First actuation means 121 has a first shaft 125 connected to
the first guide sleeve 123 by fastening means 127. The second
actuation means 122 has a second shaft 126 connected to the second
guide sleeve 124 by a second fastening means 128.
It will be appreciated that the first and second jaws 21 and 58
have friction surfaces 92 adapted to grip the pipe 26.
The actuation means 121 and 122 may be fluid cylinders which are
hydraulically operated; or alternatively manually operated screws,
levers and other conventional mechanisms may be utilized.
As best shown in FIG. 19, the actuating means 121 urges the first
guide sleeve or synch sleeve 123 generally rearwardly along the
body 20. The first guide sleeve 123 is adapted to reciprocally
slide against the body 20. As the first sleeve 123 slides against
the body 20, it rotates the first arm 22 about the first pivot
point 23, thus disengaging the first jaw 21 from the pipe 26. The
inner surface 109 of the body 20 contacts the jaw 21 and is adapted
to afford the complete disengagement of the friction surface 92
from the pipe 26. If the rear end of the first jaw 21 disengages
the pipe 26 first, the axially remote rear upper corner 129 of the
first jaw 21 will contact the inner surface 109 of the body 20.
Further rotation of the first arm 22 will tend to cause the first
jaw 21 to pivot about the point where the corner 129 contacts the
surface 109. Thus, further rotation of the first arm 22 will
facilitate the disengagement of the front end of the first jaw 21
from the pipe 26. It will be appreciated that the jaws 21 and 58
shown in FIG. 1 may also contact the inner surface of the body 20
during disengagement in the same manner as that described
above.
The second actuation means 122, second guide sleeve 124, second arm
57 and second jaw 58 operate in a similar manner.
The means for engaging and disengaging the jaws 21 and 58 from the
pipe 26 illustrated in FIGS. 18 and 19 has utility in applications
where accurate alignment of the jaws 21 and 58 is desirable. The
sleeves 123 and 124 are well adapted to permit precise alignment of
the jaws 21 and 58, respectively, by adjusting the position of the
extensions 117 and 118 upon the sleeves 123 and 124, respectively.
It will be appreciated that conventional adjustment means may be
provided for adjusting the position of the extensions 117 and 118
upon the sleeves 123 and 124. It will also be appreciated that the
sleeves 123 and 124 may be formed into a single sleeve
substantially encircling the body 20.
It will be appreciated by those skilled in the art that the jaws 21
and 58 may be fixedly connected to the arms 22 and 57. Such an
embodiment would preferably include a counter-sunk zone within the
inner surface 109 of the body 20 to permit the radially outward
rotation of the jaws 21 and 58.
SUMMARY AND ADVANTAGES OF THE INVENTION
It will be appreciated that in constructing a cylinder gripping
apparatus according to the present invention, certain significant
advantages are provided.
In particular, a cylinder gripping apparatus according to the
present invention permits a cylinder, pipe or tube to be held by a
gripping force which is proportional to an axial force tending to
urge the cylinder, pipe or tube in an unwanted direction. A
cylinder gripping apparatus according to the present invention
provides an interfacing assembly which develops a radial
counterforce or gripping force in response to an axial force upon
the cylinder which is proportional to the axial force. Thus, as the
axial force tending to urge the cylinder in an unwanted direction
increases, the gripping force will increase proportionally in
response to the increase axial force.
In addition, a cylinder gripping apparatus according to the present
invention provides an interfacing assembly which is more
economically constructed and which is adapted to withstand greater
forces between the jaw and the body. The elimination of arms which
are pivotally connected by pins to the jaw and the body eliminates
the requirement that the pins be sufficiently strong to withstand
the forces between the arm and the body.
Moreover, the cylinder, pipe or tube need not be perfectly centered
within the body. A cylinder gripping apparatus according to the
present invention permits the jaw to move transversely with respect
to the axis of the body and thereby align into engagement with a
cylinder which is deformed or which is not perfectly centered
within the body.
A cylinder gripping apparatus according to the present invention
includes the further advantage of providing an interfacing assembly
which may be used in connection with a hydrostatic testing
apparatus for high pressure testing. The interfacing assembly is
adapted to withstand greater forces than the embodiment disclosed
in the prior art.
A cylinder gripping apparatus according to the present invention
includes the further advantage of providing utility as a snubber,
safety hanging apparatus or blowout preventer for use in connection
with wellhead operations. In such an application, the cylinder
gripping apparatus provides the advantage of jaws which do not have
to be completely released from the pipe in order to pass couplings.
Thus, the risk of dropping the pipe or having a blowout while
couplings are being passed is avoided. A blowout preventer, snubber
or safety hanging apparatus constructed according to the present
invention will provide a safety feature in that the gripping force
generated will be proportional to the axial and Torsional forces
upon the pipe.
A cylinder gripping apparatus according to the present invention
may employ offset floating lugs which provide the advantage of a
gripping force which is also proportional to the rotational forces
or torque upon the cylinder, tube of pipe being gripped. The offset
floating lugs act as tongs to prevent rotation, in addition to
gripping the pipe to prevent axial movement.
A platform jacking apparatus constructed in accordance with the
present invention will provide a safe method of jacking drilling
platforms providing a gripping force upon the platform leg which is
proportional to the weight of the drilling platform.
Leveling of a drilling platform is simple and safe. A jacking
distance of a fraction of an inch may be achieved, if desired,
because one sheet of jaws can grip the platform leg at any point
along the leg, while actuation means can be used to slide the
platform any desired distance along the platform leg. Gripping is
automatic. The jacking distance is not constrained by any
requirement that shear pin holes be aligned or that gears be
meshed. The platform may be jacked up or leveled without completely
releasing any one of the platform legs.
Thus, it is apparent that there has been provide in accordance with
the invention, a cylinder gripping apparatus that substantially
incorporates the advantages set forth above. Although the present
invention has been described in conjunction with specific forms
thereof, it is evident that many alternatives, modifications, and
variations will be apparent to those skilled in the art in light of
the foregoing disclosure. Accordingly, this description is to be
construed as illustrative only and is for the purpose of teaching
those skilled in the art the manner of carrying out the invention.
It is to be understood that the forms of the invention herewith
shown and described are to be taken as the presently preferred
embodiments. Various changes may be made in the shape, size and
arrangement of parts. For example, equivalent elements or materials
may be substituted for those illustrated and described herein,
parts may be reversed, and certain features of the invention may be
utilized independently of the use of other features, all as would
be apparent to one skilled in the art after having the benefit of
this description of the invention.
It will be appreciated that in constructing a hydrostatic testing
apparatus according to the present invention, certain signficant
advantages are provided.
In particular, a hydrostatic testing apparatus according to the
present invention permits the hydrostatic testing of a vareity of
pipe sizes with a single testing apparatus. In addition, pipe with
a bell end, coupling end or upset portion may be effectively capped
by the apparatus. An apparatus according to the present invention
permits the axial centering of various sizes of pipe, and permits
axial centering of pipe having an upset portion, bell end or
coupling end.
A hydrostatic testing apparatus according to the present invention
permits the expungement of air or other gas from the interior
pressurized zone of the pipe and apparatus, thus reducing the
hazard of explosion during testing.
A hydrostatic testing apparatus with replaceable jaw tooth segments
is provided to facilitate effective gripping of various pipe sizes
and to facilitate the replacements of worn jaws. A jaw tooth
assembly is provided utilizing parallel arms and a pin mounting
which is parallel to the axis of the pipe, and dual parallel links
are provided for coupling to the body. This construction permits a
more economical and practical hydrostatic testing apparatus to be
constructed utilizing only two jaws to grip the pipe. The parallel
mounted pin facilitates the more even distribution of a gripping
force to the pipe, thus minimizing hoop stresses upon the pipe.
A hydrostatic testing apparatus constructed with a tension member
in the rear zone of the apparatus provides the advantage of an
apparatus which may be constructed more economically and with less
reinforcement in the sides of the apparatus.
The invention provides a fluid-tight seal even for pipe that is
dirty, rusty, or rough. A seal according to the present invention
provides the additional advantage of being pre-stressed to provide
a fluidtight seal with the pipe even under low pressure. A seal
according to the present invention has the advantage of permitting
itself to be flushed during successive hydrostatic tests, thereby
removing dirt and other foreign matter from between the lips of the
seal.
A hydrostatic testing apparatus according to the present invention
includes the further advantage of providing a seal adapted for high
pressure testing. A sealing ring inhibits the extrusion of the
flexible seal during high pressure testing.
A hydrostatic testing apparatus according to the present invention
provides a holding force for holding the apparatus onto the end of
the pipe where the holding force is generated by the internal
pressure of the fluid in the pipe, and which is larger and
proportional to the internal pressure. A mechanism is provided for
evenly distributing the holding force across the outer surface of
the pipe.
Thus it is apparent that there has been provided in accordance with
the invention, a hydrostatic testing apparatus that substantially
incorporates the advantages set forth above. Although the present
invention has been described in conjunction with specific forms
thereof, it is evident that many alternatives, modifications, and
variations will be apparent to those skilled in the art in light of
the foregoing disclosure. Accordingly, this description is to be
construed as illustrative only and is for the purpose of teaching
those skilled in the art the manner of carrying out the invention.
It is to be understood that the forms of the invention herewith
shown and described are to be taken as the presently preferred
embodiments. Various changes may be made in the shape, size and
arrangement of parts. For example, equivalent elements or materials
may be substituted for those illustrated and described herein,
parts may be reversed, and certain features of the invention may be
utilized independently of the use of other features, all as would
be apparent to one skilled in the art after having the benefit of
this description of the invention.
* * * * *