U.S. patent number 3,838,613 [Application Number 05/407,698] was granted by the patent office on 1974-10-01 for motion compensation system for power tong apparatus.
This patent grant is currently assigned to Byron Jackson Inc.. Invention is credited to Carl Alfred Wilms.
United States Patent |
3,838,613 |
Wilms |
October 1, 1974 |
MOTION COMPENSATION SYSTEM FOR POWER TONG APPARATUS
Abstract
A power well pipe tong assembly having a back-up tong unit and
power tong unit above the back-up unit and interconnected for
vertical movement one relative to the other on parallel horizontal
planes and a presser device actuated by fluid pressure interposed
between the two tong units to counterbalance the weight of the
power tong during such vertical movement.
Inventors: |
Wilms; Carl Alfred (La Habra,
CA) |
Assignee: |
Byron Jackson Inc. (Long Beach,
CA)
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Family
ID: |
26910741 |
Appl.
No.: |
05/407,698 |
Filed: |
October 18, 1973 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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216182 |
Jan 7, 1972 |
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134552 |
Apr 16, 1971 |
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Current U.S.
Class: |
81/57.34;
173/164; 81/57.16 |
Current CPC
Class: |
E21B
19/16 (20130101) |
Current International
Class: |
E21B
19/16 (20060101); E21B 19/00 (20060101); B25b
013/50 (); E21b 019/16 () |
Field of
Search: |
;81/57.15,57.16,57.22,57.24,57.34,57.36 ;173/43,164 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Smith; Al Lawrence
Assistant Examiner: Peters; J. C.
Attorney, Agent or Firm: Evans, Jr.; John O.
Parent Case Text
BACKGROUND OF THE INVENTION
This application is a continuation of copending application Ser.
No. 216,182, filed Jan. 7, 1972, for "Motion Compensation System
for Power Tong Apparatus", now abandoned, which application is a
continuation-in-part of application Ser. No. 134,552, filed Apr.
16, 1971, for "Combined Back Up Tong and Power Tong with Joint
Motion Compensation", now abandoned.
Claims
What is claimed is:
1. Pipe tong apparatus comprising: a power tong assembly including
a pipe back-up tong unit disposed in horizontally parallel relation
below a pipe rotating power tong unit, and presser means interposed
between said tong unit to apply separating force between said tong
units to substantially counterbalance the weight of said power tong
unit as said power tong unit is vertically moved with respect to
said back-up tong unit, said counterbalance means comprising a
bladder interposed between said tong means, and means for supplying
fluid under pressure to said bladder, said bladder acting on said
power tong means to apply said force.
2. A tong assembly comprising: back-up tong means for holding a
first pipe against rotation, power tong means for rotating a second
pipe, said pipes having complementally threaded joint parts
engageable and disengageable upon rotation of said second pipe,
connector means interconnecting said tong means for movement only
toward and away from one another responsive to threaded engagement
and disengagement of said joint parts, and presser means interposed
between said tong means to apply a force to separate said tong
means, whereby to substantially counterbalance the weight of said
power tong means when said back-up tong means is supported in a
horizontal plane and said pipe is disposed vertically, wherein said
presser means comprises a bladder between said tongs.
3. Pipe tong apparatus comprising: a power tong assembly including
a pipe back-up tong unit disposed in horizontally parallel relation
with a pipe rotating power tong unit; a vertically disposed support
column provided with lower bearing means adapted to be mounted to a
fixed support in a well derrick and upper bearing means adapted to
be connected to the structure of the derrick to provide vertical
and horizontal support for said column while permitting said column
to pivot horizontally; a vertically movable support collar fitted
about said column and supported in alignment for movement up and
down said column; a pipe tong support yoke means rigidly mounted to
said support collar at its first end to extend horizontally and
radially pivotable from said support column; said yoke structure
being adapted to receive and support said power tong assembly
through a supporting cradle means mounted to the second end of said
yoke; and presser means interposed between said tong units to apply
separating force between said tong units to substantially
counterbalance the weight of said power tong unit through vertical
movement of said power tong unit, including a power source
providing linear movement mounted in upright position adjacent said
column with its lower end mounted to the lower end of said column
and its upper end connected through a flexible force transfer means
to said support yoke, said flexible force transfer means being
anchored relatively between said yoke structure and said support
column and being connected across a force transfer crosshead means
mounted to the upper end of said power source.
4. Pipe tong apparatus comprising: a power tong assembly including
a pipe back-up tong unit disposed in horizontally parallel relation
with a pipe rotating power tong unit; a vertically disposed support
column provided with lower bearing means adapted to be mounted to a
fixed support in a well derrick and upper bearing means adapted to
be connected to the structure of the derrick to provide vertical
and horizontal support for said column while permitting said column
to pivot horizontally a vertically movable support collar fitted
about said column and supported in alignment for movement up and
down said column; a pipe tong support yoke means rigidly mounted to
said support collar at its first end to extend horizontally and
radially pivotable from said support column; said yoke structure
being adapted to receive and support said power tong assembly
through a supporting cradle means mounted to the second end of said
yoke; and presser means interposed between said tong units to apply
separating force between said tong units to substantially
counterbalance the weight of said power tong unit through vertical
movement of said power tong unit, wherein said cradle means
includes means providing resiliently pivoted vertical support of
said back-up tong unit in parallel relation to said yoke structure
and providing support with limited vertical and radial movement of
said power tong unit with respect to said back-up tong unit and to
said support yoke.
5. The positioning apparatus of claim 3, wherein said flexible
force transfer means includes chain means anchored to the lower end
of said support column and to said support yoke and said force
transfer crosshead means includes chain sprocket means.
6. The positioning apparatus of claim 3, wherein said cradle means
includes means providing resiliently pivoted vertical support of
said back-up unit in parallel relation to said yoke structure and
providing support with limited vertical and radial movement of said
rotating unit with respect to said back-up unit and to said support
yoke.
7. The positioning apparatus of claim 3, wherein said power source
comprises a piston and cylinder unit having a piston rod connected
to said force transfer crosshead means.
8. Th positioning apparatus of claim 7 including hydraulic fluid
power means for actuating said piston and cylinder unit.
9. Pipe tong apparatus comprising: a power tong assembly including
a pipe back-up tong unit disposed in horizontally parallel relation
with a pipe rotating power tong unit; a vertically disposed support
column provided with lower bearing means adapted to be mounted to a
fixed support in a well derrick and upper bearing means adapted to
be connected to the structure of the derrick to provide vertical
and horizontal support for said column while permitting said column
to pivot horizontally; a vertically movable support collar fitted
about said column and supported in alignment for movement up and
down said column; a pipe tong support yoke means rigidly mounted to
said support collar at its first end to extend horizontally and
radially pivotable from said support column; said yoke structure
being adapted to receive and support said power tong assembly
through a supporting cradle means mounted to the second end of said
yoke; and presser means interposed between said tong units to apply
separating force between said tong units to substantially
counterbalance the weight of said power tong unit through vertical
movement of said power tong unit, said presser means comprising a
bladder interposed between said tong means, and means for supplying
fluid under pressure to said bladder, said bladder acting on said
power tong unit to apply said force.
10. A pipe tong assembly for making up or breaking out threaded
joints in well pipe comprising a horizontally disposed back-up tong
unit engageable with a vertically disposed, first threaded pipe
joint part to hold said part and said back-up tong unit against
rotation and against vertical movement relative to each other,
means for supporting said back-up tong unit in a selected vertical
position upon a stationary base, a power tong unit disposed above
said back-up tong unit and engageable with a second complementally
threaded pipe joint part that is aligned with said first threaded
pipe joint part for rotating said second threaded pipe joint part
into or out of threaded engagement with said first threaded pipe
joint part while holding said second threaded pipe joint against
vertical movement relative to said power tong unit, and vertically
expandable and contactible counterbalance means carried by said
back-up tong unit and associated with said power tong unit for
yieldably supporting said power tong unit upon said back-up tong
unit for vertical movements with respect to said back-up tong unit,
said counterbalance means being constructed and arranged to apply
an upward force to said power tong unit substantially equal to the
weight of said power tong unit as said power tong unit is
vertically moved in response to the threading of said second
threaded pipe joint part into or out of threaded engagement with
said first threaded pipe joint part, said counterbalance means
being the sole means for vertically supporting said power tong
unit, said counterbalance means comprising a bladder interposed
between said back-up tong unit and said power tong unit, and means
for supplying fluid under pressure to said bladder, said bladder
acting on said power tong unit to apply said upward force.
11. A pipe tong assembly for making up or breaking out threaded
joints in vertically disposed well pipe comprising: a base member;
a back-up tong unit; means for mounting said back-up tong unit on
said base member and in horizontal disposition, and for vertical
movement and also for horizontal movement with respect to said base
member; a power tong unit; means for mounting said power tong unit
on and superjacent to said back-up tong unit and in horizontal
disposition, and for limited vertical movements with respect to
said back-up tong unit; said back-up tong unit having means
releasably engageable with a vertically disposed, lower threaded
pipe joint part to hold said part and said back-up tong unit
against relative rotation and vertical movement therebetween; said
power tong unit having means releasably engageable with an upper
complementally threaded pipe joint part that is aligned with said
lower threaded pipe joint part for rotating said upper threaded
pipe joint part into and out of threaded engagement with said lower
threaded pipe joint part while holding said upper pipe joint part
and said power tong unit against relative vertical movement
therebetween; counterbalance means including vertically expandable
and contractible means carried by said back-up tong unit,
positioned between said back-up tong unit and said power tong unit,
and yieldably supporting said power tong unit for vertical
movements with respect to said back-up tong unit, said
counterbalance means being constructed and arranged to apply an
upward force to said power tong unit substantially equal to the
weight thereof as said power tong unit is vertically moved with
respect to said back-up tong unit in response to the threading of
said upper threaded pipe joint part into and out of threaded
enagement with said lower threaded pipe joint part; and connector
means interconnecting said power tong unit and said back-up tong
unit constraining said power tong unit to move horizontally with
said back-up tong unit as the latter is moved horizontally with
respect to said base member.
12. A pipe tong assembly as defined in claim 11, wherein said means
for mounting said back-up tong unit on said base member includes
pivot means having a vertical pivot axis for horizontal pivotal
movement of said back-up tong unit with respect to said base
member.
13. A pipe tong assembly as defined in claim 11, wherein said
vertically expandable and contractible means comprises
pneumatically expandable and contractible means.
14. A pipe tong assembly as defined in claim 11, said vertically
expandable and contractible means being disposed substantially at
the center of gravity of said power tong unit.
15. A pipe tong assembly as defined in claim 11, said vertically
expandable and contractible means comprising a bladder interposed
between said back-up tong unit and said power tong unit, and means
for supplying fluid under pressure to said bladder, said bladder
acting on said power tong unit to apply said upward force.
16. A pipe tong assembly as defined in claim 11, said vertically
expandable and contractible means comprising a piston and cylinder
means interposed between said back-up tong unit and said power tong
unit, said piston and cylinder means acting on said power tong unit
to apply said upward force.
17. A pipe tong assembly as defined in claim 11, wherein said
connector means also constrains said power tong unit to move
vertically towards and away from said back-up tong unit only on
parallel planes.
18. A pipe tong assembly as defined in claim 17 including keeper
means for limiting movement of said power tong unit away from said
back-up tong unit to a location at which said tong units both
engage said joint parts when said joint is to be made up.
19. A pipe tong assembly as defined in claim 11, wherein said
vertically expandable and contractible means comprises pressure
fluid containing means, said counterbalance means including a make
up pressure regulator and a break out pressure regulator for
maintaining selected constant pressures in said pressure fluid
containing means and to respectively maintain said upward force
slightly greater than the weight of said power tong unit during the
making up of said joints and slightly less than the weight of said
power tong unit during the breaking out of said joints, and means
including selector valve means for selectively communicating said
regulators with said pressure fluid containing means.
20. Pipe tong apparatus comprising: a power tong assembly including
a pipe back-up tong unit disposed in horizontally parallel relation
below a pipe rotating power tong unit, presser means interposed
between said tong units to apply separating force between said tong
units to substantially counterbalance the weight of said power tong
unit through vertical movement of said power tong unit with respect
to said back-up tong unit; a vertically disposed support column
provided with lower bearing means adapted to be mounted to a fixed
support in a well derrick and upper bearing means adapted to be
connected to the structure of the derrick to provide vertical and
horizontal support for said column while permitting said column to
pivot horizontally; a vertically movable hollow support collar
fitted about said column and supported in alignment for movement up
and down said column by roller means rigidly mounted with said
roller and mounted in rolling contact with said column; a pipe tong
support yoke means rigidly mounted to said support collar at its
first end to extend horizontally and radially pivotable from said
support column; said yoke structure being adapted to receive and
support said power tong assembly through a supporting cradle means
mounted to the second end of said yoke; a power source providing
linear movement mounted in upright position adjacent said column
member with its lower end mounted to the lower end of said support
column and its upper end connected through a flexible force
transfer means to said support yoke, said flexible force transfer
means being anchored relatively between said yoke structure and
said support column and being connected across a force transfer
crosshead means mounted to the upper end of said power source.
Description
In the drilling of well bores, such as oil and gas wells, into the
earth and in the periodic round-tripping of the drill string, it is
necessary to "make up" and "break out" the tool joints of stands or
lengths of drill pipe which together constitute the drill string.
As is well known such tool joints are generally threaded joints
consisting of an internally threaded "box" on the drill pipe which
is disposed in the well bore and supported in the usual rotary
table, and an externally threaded "pin" on the length or stand of
drill pipe which is being added to or removed from the drill
string. Such tool joints also generally include radial shoulders on
the box and on the pin which engage with one another when the joint
is tight.
To tightly make up such a tool joint or break out the joint, as the
case may be, requires a substantial force which is applied to the
respective tool joint pin and box sections by rotating the length
or stand of drill pipe which is being added or removed, while the
drill string in the well bore is held stationary. To initially
shoulder the tool joint or to remove the pin from the box, the
rotatable pipe stand is generally rotated at high speed to save
time, per joint, such operation being referred to as "spinning" in
or out, as the case may be.
The spinning operation, in any event, involves relative axial
movement of the tool joint shoulders into and out of engagement,
such axial movement being caused by the threads on the pin and in
the box.
For the purpose of spinning and making up and breaking out tool
joints in well drilling pipe, various power tongs have been
heretofore provided and are adapted to grip the tool joint of the
length or stand of drill pipe suspended in the derrick and impart
rotation thereto. In addition, various back up tongs have been
heretofore provided for engaging and holding stationary the tool
joint at the upper end of the drill string which is supported in
the usual master bushing by wedges or "slips" which are movable
between pipe supporting and out of the way positions, either
manually or by power actuated means.
Such operations, using a power tong and a back-up tong, inherently
require that the power tong move towards and away from the back-up
tong during the spinning of the pipe stand being added to or
removed from the drill string, since if such movement cannot take
place, then, the tool joint section engaged by the power tong will
be forced to slide relative to the gripping means of the power tong
or the tongs will be relatively cocked.
THE PRIOR ART
A power tong and a back-up tong combination which typifies the
prior art, is shown and described in U.S. Pat. No. 3,518,903,
granted July 7, 1970, wherein the back-up tong is suspended beneath
the power tong, and the power tong is supported by a crane based on
the derrick floor. Springs are interposed between the power tong
and the back-up tong, and pin means shiftably supports the back-up
tong beneath the power tong.
Such power tongs are also disclosed, for example, in the U.S.
patent applications of Bela Geczy et al, filed Apr. 16, 1971, Ser.
No. 134,554, for "Chain Driven Spinning Make Up and Break Out
Tongs", now U.S. Pat. No. 3,691,875, issued Sept. 19, 1972; and
Carl A. Wilms, filed Apr. 16, 1971, Ser. No. 134,553, for "Chain
Actuated Pipe Tongs". The disclosures of these identified patent
applications are specifically incorporated herein by reference.
SUMMARY OF THE INVENTION
The present invention provides a power tong and back-up tong
combination wherein the respective tongs are interconnected for
relative vertical movement on planes normal to the direction of
relative movement of the tool joint parts when they are being made
up or broken out, whereby relative cocking of the tongs on either
tool joint section is prohibited.
In addition, the present invention provides such a combination in
which the back-up tong is supported or suspended above the derrick
floor and the power tong is supported on the back-up tong by means
which essentially counterbalance the weight of the power tong, so
that the latter is easily movable vertically as a result of
spinning of the pipe stand by the power tong, which spinning
results in upward or downward movement of the power tong due to the
progressive disengagement or engagement of the complemental threads
of the pin and box sections of the tool joint.
More particularly, the present invention provides fluid pressure
containing means or presser means acting between the back-up tong
and the power tong in such a manner that the weight of the power
tong may be substantially nullified. For example, when the tong
combination is being employed to make up tool joints, under which
circumstances the power tong must be in a starting position spaced
upwardly from the back-up tong, the fluid pressure containing or
presser means may over compensate for the weight of the power tong
to a slight extent, so that as the tool joint spins up, the power
tong is easily moved downwardly. On the other hand, for example,
when the tong combination is being employed to break out tool
joints, under which circumstances the power tong must be in its
lower starting position, the presser means may compensate for
slightly less than the weight of the power tong, so that the power
tong is easily moved upwardly as the tool joint is being spun
out.
In accomplishing the foregoing, the objectives of the invention
include the provision of a power tong and back up tong combination
which is simple in its construction, durable, and easy to control
and operate.
This invention possesses many other advantages, and has other
purposes which may be made more clearly apparent from a
consideration of the forms in which it may be embodied. These forms
are shown in the drawings accompanying and forming part of the
present specification. They will now be described in detail, for
the purpose of illustrating the general principles of the
invention; but it is to be understood that such detailed
description is not to be taken in a limiting sense.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side elevation of a power tong and back-up tong
combination made in accordance with the invention and supported
above the floor of a drilling derrick, and showing a drill string
and a pipe stand in the relatively unthreaded positions;
FIG. 2 is a top plan of the combination of FIG. 1;
FIG. 3 is a side elevation of the power tong and back-up tong of
FIG. 1, but showing them in a position at which the tool joint is
shouldered;
FIG. 4 is a detail view in vertical section, through a typical
connector pin assembly, as taken on the line 4--4 of FIG. 2;
FIG. 5 is a detail view in vertical section through the fluid
pressure containing means and portions of the tongs, as taken on
the line 5--5 of FIG. 2;
FIG. 6 is an elevational view of an alternate embodiment of the
present invention;
FIG. 7 is a partially cut away plan view taken along the line 7--7
of FIG. 6;
FIG. 8 is a sectional view of an alternate embodiment of the fluid
pressure containing means or presser means as taken along the line
8--8 of FIG. 7;
FIG. 9 is a partly sectional elevational view taken along the line
9--9 of FIG. 6;
FIG. 10 is a partially sectional elevational view taken along the
line 10--10 of FIG. 9;
FIG. 11 is a sectional view taken along the line 11--11 of FIG.
10;
FIG. 12 is a sectional view taken along the line 12--12 of FIG. 6;
and
FIG. 13 is a schematic illustration of the presser means and an
adjustable pressure system for use with the same.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
As seen in FIGS. 1, 2, 3, 6 and 7 of the drawings, the power tong
and back-up tong combination BT of the present invention generally
comprises a back-up tong assembly B and a power tong assembly T,
support means S for the back-up tong B, a plurality of connector
means C enabling relative movement of the tongs T and B toward and
away from one another, and presser means or fluid pressure
containing means P interposed between the tongs T and B and
operable to more or less counterbalance the weight of the power
tong T to allow the latter to move downwardly during the make up of
a tool joint J and upwardly during the break out of the tool joint
J in the drill pipe DP.
The power tong T may be of any type, including by way of example,
that shown and described in detail in the aforementioned U.S. Pat.
No. 3,518,903 and U.S. patent disclosures. Likewise, the back-up
tong B may be of any type, including by way of example, that shown
and described in said patent and patent disclosures. Such tongs are
well known in the art and without requiring detailed illustration
and description herein will be understood to be used, when
supported in the usual derrick or on the derrick floor, to thread
the pin end 1 of the tool joint J into the box end 2, from the
positions shown in FIG. 1 to the position shown in FIG. 3, at which
the joint J is tightly shouldered, when making up joints, or to
unthread the pin 1 from the box 2 when the joint J is being broken
out. During such operations, the box end 2 is held against rotation
in the back-up tong B, while rotation of the pin end 1 is effected
by the power tong T. Since both tongs tightly grip the tool joint
parts, it is necessary that the power tong T move between the
elevated position, spaced above the back-up tong B, as seen in FIG.
1, and the lower position, as seen in FIG. 3, the distance between
these two positions being equal to the axial movement of the pin 1
caused by the threads as the joint J is made up and broken out.
In order to rotate the pin end 1 of the joint J, the power tong,
generally, comprises gripping jaws 4 which are actuated from
retracted positions to gripping positions, as seen in FIG. 2, and
the pin end 1 is then revolved by a suitable power source, such as
a hydraulic motor M through suitable gearing (not shown) in a
housing 5 on the power tong body 6. A similar jaw system (not
shown) is typically included in the back-up tong B, but the jaws
are held against revolution when actuated into engagement with the
box end 2 of the joint J. As previously indicated the details of
the tongs T and B may vary, and examples including gripping jaws
and operating means therefor, are abundantly illustrated in the
above-identified U.S. patent and are otherwise well known.
In order to support the drill pipe in the well bore, with the upper
end or box 2 disposed, as seen in FIG. 1, in position for gripping
engagement by the back-up tong B, suitable slip mechanism, say a
power slip apparatus PS is supported on the derrick floor F and is
operable to releasably engage the pipe below the box end 2, so that
the drill pipe string is suspended in the well from the usual
rotary table R, all as is well known.
The supporting means S previously referred to may take any
convenient form, such as the customary cable support by which the
tong combination is suspended from the derrick in a horizontal
disposition and steadied by a stiff arm or other supporting means
such as a pedestal or carriage of the nature shown in FIG. 6. In
FIG. 1 the supporting means is shown as being of the suspended
type. More particularly, a U-shaped member or yoke 10 is shown as
straddling the power tong T and being connected by suitable
fasteners 11 to the body of the back-up tong B, the connection
being obviously the same at both sides. The bight portion 12 of the
yoke 10 has a centrally located, upstanding ear 13 adapted to be
connected to a clevis 14 at the lower end of a supporting cable 15
which will be understood to extend upwardly to a suitable
connection (not shown) with hoist mechanism which may be employed
to adjust the elevation of the tong combination with respect to the
derrick floor F and thus the box 2 of the drill pipe. In addition,
a stiff arm 16 is generally illustrated as being connected to one
side of the tong combination adjacent the end remote from the pipe
DP to stabilize the combination and provide a safety means to
prevent reactive torque from causing the tong combination to swing
about the drill pipe DP if the power tong T is operated without
gripping the box 2 with the back-up tong B. Otherwise, when the
back-up tong is gripping the box 2 the reaction torque is taken by
the connector means C.
These connector means C are conveniently located, preferably
adjacent to the ends of the tong combination and, as previously
indicated, function to interconnect the power tong T with the
back-up tong B in such a manner that the power tong is vertically
shiftable relative to the back-up tong, between the positions shown
in FIGS. 1 and 3, in parallel relation to the back-up tong. In
other words, the two tongs are horizontally extended on parallel
planes and are vertically movable, one relative to the other, and
the connector means C constrain the tongs to such movement.
As seen in FIG. 2, the connector means as illustrated are
triangularly related with a pair of connector means at opposite
forward corners of the tong combination and a third connector means
at the rear or other end of the combination. A typical connector
means C for the embodiment shown in FIGS. 1 and 2 is best
illustrated in FIG. 4. The tong T has an ear 20 providing a bore 21
in which a connector pin 22 is suitably affixed, the lower portion
of the pin 22 extending downwardly and slidably through a bushing
23 which is affixed in a bore 24 provided in an ear 25 on the tong
B. At its lower end, the pin 22 has a keeper in the form of a
washer 26 secured by a fastener 27 to the pin 22 and having a
diameter such that the washer will abut beneath the ear 25 to limit
upward movement of the tong T.
It will now be understood that with the structure thus far
described, the two tongs T and B are free to move relatively
vertically while suspended by the supporting means S. Such vertical
movement is necessary when the joint parts 1 and 2 of the joint J
are being threaded in or out, to compensate for the relative axial
movement of the joint parts 1 and 2, without causing longitudinal
slippage of the tong gripping means on the joint parts 1 and 2. The
connector means C hold the tongs T and B in parallel relation.
However, the power tong T is typically quite heavy, and therefore
the presser means P previously referred to is provided to more or
less counterbalance the weight of the power tong T to relieve the
pipe gripping means from the load of the tong T.
The fluid pressure containing means P as illustrated in FIG. 5
comprises a presser bladder 30 of generally flat, circular form,
interposed between the bottom wall 31 of the power tong T and the
top wall 32 of the back-up tong B. In the illustrated embodiment,
the bladder seats in a complemental cavity 33 in the wall 32 of the
back-up tong.
The presser bladder 30 is composed of elastomeric material and may
be suitably reinforced against rupture or other failure. Centrally
of the bottom wall 34 of the bladder 30 is a sleeve 35 which is
suitably bonded in an opening 36 in the bladder wall 34 and adapted
to extend downwardly into an opening 37 in the tong wall 32 and
onto a cylindrical neck 38 of a fluid pressure inlet fitting 39
which is suitably affixed beneath the tong wall 32, as by welding
at 40. Suitable seal means 41 are provided between the opposing
cylindrical surfaces of the sleeve 35 and the neck 38, and fluid
conduit 42 is connected to the fitting 39 so that fluid may be
supplied to the interior of the presser bladder 30 at a selected
and regulated pressure as will be later described.
Since the purpose of the presser bladder 30 is to more or less
counterbalance the weight of the tong T, to facilitate its movement
vertically during the making up and breaking out of pipe joints J,
counterbalance presser means P is preferably located beneath the
power tong T or applies lift to the tong T substantially at the
center of gravity of the tong T which of course varies from power
tong to power tong. In addition, while a bladder is illustrated as
a simple, relatively inexpensive yet effective counterbalance
device, it will be understood that other fluid pressure responsive
presser devices as later described, are also applicable, the
essential point being that the weight of the power tong is more or
less counterbalanced as it moves upwardly or downwardly with the
pin end or joint part 1 during the breaking out and making up of
the joints J, so that the weight of the power tong T is not applied
to the pipe gripping means or jaws 4 of the power tong T.
FIGS. 6-12 illustrate an alternate embodiment of the invention
wherein the same indicia are assigned to components corresponding
to those as previously described. The alternate embodiment as
illustrated in FIGS. 6, 7 and 8 includes positioning apparatus
having a vertically disposed column 76 formed of a web joined
between two parallel flanges such as an I-beam, for example. Upper
upper support 78 is connected with the top of column 76 as by
bolted connection as shown, for example. Ypper support 78 is
connected to a pivotable upper bearing unit 80 shown in FIG. 6. A
lower support is connected to a pivotable lower bearing unit (not
shown) in turn attached to a derrick floor. An alternate tong
support means S is mounted in cantilever fashion from column 76 as
before described.
A generally hollow and elongated rectangular support collar 82 of
support means S is fitted about column 76 and adapted to be moved
up and down along column 76. Collar 82 is maintained and rigidly
supported in longitudinal movable alignment with column 76 by a
roller assembly 84 incorporated within collar 82. As shown, a
plurality of flanged rollers 86 are included in assembly 84 and
mounted to abut and roll along the inner faces of the flanges of
column 76 with the roller flanges abutting the side edges of the
column flanges to restrain collar 82 in fixed horizontal or lateral
relation with respect to the column.
A tong support yoke structure 88 is mounted to collar 82 and
projects horizontally and radially from the pivotable axis of
column 76. A power pipe tong assembly BT adapted to receive a well
pipe DP and including a back-up tong B and a rotating power tong T
is mounted within yoke 88 through a cradle assembly having cradle
units 90 and 90' comprising part of connector means C. For the
purpose of this description, the power tong assembly BT may be
considered to be of construction such as disclosed in the
previously referenced U.S. patent disclosures, for example.
Mounted in generally upright posture adjacent column 76 is a power
source adapted for linear movement which is provided as a hydraulic
piston and cylinder unit 92. As later described, power source 92 is
pivotally mounted at its lower end to the lower end of column 76
(not shown) and terminates at its upper movable end with a force
and movement crosshead unit 94. Flexible force and movement
transfer means are provided as a pair of roller chains 96 (only one
shown) which straddle power source 92 and which are respectively
meshed across chain sprockets incorporated as part of crosshead
unit 94. Chains 96 are also respectively anchored at their lower
ends to the lower end of column 76 (not shown) and extend upwardly
over crosshead unit 94 to a position below unit 94 where such
chains are respectively anchored to yoke structure 88.
Upper support assembly 78 is removably attached to column 76
through provision of downwardly projecting flanges 98 which are
respectively connected to the flanges of column 76 by means of
bolts 100. Upper support member 78 is provided as removable to
permit assembly of support collar 82 as shown in FIG. 6. Upper
bearing unit 80 is a flanged ball bearing assembly connected to
support 78 and to a cylindrical retaining bitt 102 by means of
fasteners (not shown). Bitt 102 is equipped with a plurality of
lobed and divided retainer rings such as indicated at 106 and 108.
Rings 106 and 108 are assembled with fasteners such as cap screws
110, for example. Horizontal tie bars 112 and 114 are respectively
connected to the lobes of rings 106 and 108 through clevis and pin
arrangements 116 and 118. The other ends of tie bars 112 and 114
are connected in tension to the structure (not shown) of the well
derrick. To be noted is that more than the two disclosed tie bars
may be utilized as desired to provide appropriate horizontal
stability in a particular installation.
The alternate embodiment of presser P is best shown in FIGS. 7 and
8 to include a movable piston 60 including an externally mounted
sliding bearing sleeve 62 and a fluid pressure seal means such as
seal rings 64 interposed snugly and reciprocably fitted within a
cylinder 66. As shown, cylinder 66 is firmly supported from the
bottom wall of back-up tong B through support webs 68 connected to
such bottom wall as by welding and connected in fluid sealed
relation to the closed end of cylinder 66 by means of fasteners
such as cap screws 70 and seal washers or gaskets 72 as shown. The
upper open end of cylinder 66 extends through a hole defined in the
top wall 32 of the tong B. A seal ring 74 is interposed between
cylinder 66 and the hole in tong wall 32 to maintain the interior
of tong B free of dirt and detritus as might enter
therebetween.
As shown, fluid pressure entering cylinder 66 will cause upward
movement of piston 60 into abutting contact with bottom wall 31 of
rotating power tong T. The pressing force of presser P to
counterbalance tong T as previously described is thereon
commensurate with the fluid pressure applied through conduit 42, as
later described. Of note is that the face of piston 62 which abuts
the bottom wall 31 of tong T is provided to permit free horizontal
sliding contact between the piston face and such bottom wall, such
horizontal movement being limited by the embodiments of connector
means C as heretofore described with reference to FIGS. 1-4 and
hereafter described with reference to FIGS. 6-12.
Yoke 88 (FIG. 6) of support means S includes a clevis box 120
mounted at the upper part of a load plate 122 comprising part of
collar 82 and support arms 124 and 124' mounted to and projecting
from the lower part of load plate 122. Support cradles 90 and 90'
are respectively mounted to arms 124 and 124', as later described
with reference to FIGS. 10-12, and secured through pinned
connection to members 126 and 126' of a support fork 128 to clevis
box 120. Clevis box 120 defines a cavity which will receive chain
crosshead 94 and is provided with a chain anchor bracket 130 to
which chains 96 are secured by bolted connection as shown in FIG.
6. Support means S also includes a torque section alignment pin 188
projecting from back-up tong B and received in a hole defined in
rotating power tong T as shown in FIGS. 6 and 7. The installation
of alignment pin 188 may be similar to an inverted arrangement of
FIG. 4 without provision of washer 26 as shown.
Power source 92 as provided includes a piston and cylinder unit
having a cylinder 132 with a piston rod 134 extending from the
cylinder. Chain crosshead 94 is mounted to the distal end of rod
134 and cylinder 132 is pivotally mounted to the lower end of
column 76 (not shown). Cylinder 132 is equipped with a fluid
fitting (not shown) through which fluids under pressure may be
forced into or discharged from the cylinder to cause extension and
retraction of piston rod 134 with corresponding perpendicular
movement of support yoke 88 as previously described. Though
compressible fluids such as air may be used, incompressible
hydraulic fluids such as oil is preferred in the operation of power
source 92.
FIGS. 6, 7 and 9-11 show the supporting cradle including cradle
units 90 and 90'. Cradle unit 90' is provided of construction which
is in mirror image of the construction of cradle unit 90 and
accordingly need not be described in detail. FIGS. 10, 11 and 12
best show the details of cradle unit 90. Cradle unit 90 generally
includes a supporting guide 136 formed at the extremity of support
arm 124 which guides and supports a tong unit carrier frame 138 in
pivoting and raidally movable relation through a roller unit 140 as
shown.
Supporting guide 136 is formed of generally rectangular
configuration with a pair of upwardly extending ears which form a
clevis 142 for attachment by means of a pin to support fork 128.
Parallel trackways 144 are horizontally and radially defined within
guide 136 and closed at the distal end of support arm 124 by a
closure bar 146 connected across the trackways to guide 136 by
fasteners such as cap screws 148 as shown. A flanged guide block
150 is snugly fitted in sliding relation within trackways 144 with
the flanges of the guide block abutting the sides of the trackways
and maintaining the guide block in radial alignment with support
arm 124. Adjustable radial support of guide block 150 is provided
by a threaded stud 152 projecting from the guide blocks through a
hole in closure bar 146 with threaded lock nuts 154 adjustably
threaded on stud 152 and tightened to lock on either side of bar
146. A short machined slot 156 having circular ends is horizontally
defined in guide block 150 which slot receives roller 140 and
permits limited radial movement of the roller within the slot for
purposes later described. Roller 140, as disposed within slot 156,
is secured by means of a pin to a clevis 158 formed as an upper
part of carrier frame 138 in a manner as shown to cause carrier
frame 138 to be suspended in pivoted and radially movable relation
through roller 140 from guide block 150.
Carrier frame 138 is adapted to be rigidly connected to pipe
back-up unit B by fasteners such as cap screws 160 to support lugs
162 which project from unit B as shown. As shown, four guide
rollers 164 are mounted in rectangular formation on carrier frame
138 by means of pins to accommodate a guide bar 166 and maintain
the guide bar in vertically movable alignment. Guide bar 166 is
adapted to be rigidly connected by means of fasteners such as cap
screws 168 to pipe rotating power unit T as shown.
Vertical movement of pipe rotating unit T relative to pipe back-up
unit B is maintained within a predetermined limit by means of a dog
170 which is connected to and projects from guide bar 166 into a
limit slot 172 defined in carrier frame 138 as shown.
The construction of cradle unit 90 as shown provides parallel
alignment and limited vertical movement between rotating unit T and
back-up unit B while permitting adjustable limited radial movement
and vertical pivoting of the entire power tong assembly BT. The
limited radial movement of carrier frame 138 as provided by
movement of roller unit 140 within slot 156 permits slight radial
movement of power tong assembly BT with respect to column 76 to
compensate for corresponding horizontal deviations of the well pipe
within the well bore. Initial radial range adjustment is provided
by adjustment of guide block 150 through positioning of adjustment
stud 152.
Pivotal movement or "rocking" of power tong assembly BT about the
axis of roller unit 140 is resiliently limited by a stabilizing
unit 174 and 174', shown in FIGS. 6, 7 and 12. Only unit 174 needs
to be described as a flanged bracket 176 extending inwardly and
downwardly from support arm 124 of yoke 88. A bolt 178 extends
upwardly through a lug 180 projecting from back up tong B and
through a flange 182 projecting from bracket 176 and is secured in
position by adjustable lock nuts 184. A pair of resilient coil
springs 186 are disposed between lug 180, the flange 182 and lock
nuts 184 as shown. The bolt is fitted through lug 180 and flange
182 sufficiently loosely to permit the radial movement of tong
assembly BT as previously described. Such construction provides
firm yet resilient vertical support of tong assembly BT against
movement about the axis of roller unit 140. Such resilience permits
compensation for minor deviations from a vertical position of the
well pipe DP extending through tong assembly BT.
Referring to FIG. 13, an exemplary fluid pressure control system is
shown, whereby the presser bladder 30 of the fluid pressure
counterbalancing means is maintained at a selected pressure during
make up and break out of joints J. In this schematic system, it
will be noted that a pneumatic system is shown, for example, and
the conduit 42 which is connected to the presser bladder 30 is
selectively connectable to an air source conduit 50 by a suitable
selector valve SV and either of a pair of variable pressure
regulators consisting of a joint break-out regulator RB and a joint
make-up regulator RM.
Valve SU may be of any desired type and is simply shown as a
manually actuated detented, two position valve, but in automated
systems, the valve SV, obviously, may be pilot operated. In any
event, in one position, as shown in FIG. 6, the valve SV connects
the bladder conduit 42 with a conduit 51 which leads from the
regulator RB to the valve SV so that the pressure in the presser
bladder 30 is determined by the setting of the adjustable regulator
RB; and in the other position of the valve SV, the bladder conduit
42 will be connected with a conduit 52 which leads from the
regulator RM to the valve SV, so that the pressure in the bladder
30 will be determined by the setting of the adjustable regulator
RM.
To properly counterbalance the weight of the power tong T during
joint break out operations, as illustrated in FIG. 6, the regulator
RB is adjusted so that the force derived from the presser bladder
30 due to internal pressure preferably is slightly less than the
weight of tong T so that the power tong T will be initially lowered
to the starting position of FIG. 3 and as the joint part 1 moves
upwardly from the joint part 2, from the position of FIG. 3 to the
position of FIG. 1, the power tong T easily moves correspondingly.
As previously indicated, such movement occurs only in parallel
planes due to the restraint of the connector means C against
cocking of the tongs, one relative to the other. On the other hand,
when the tong combination is being employed in joint make up
operations, and the valve SV is in the alternate position from that
shown, the regulator RM is adjusted so that the force derived from
the presser bladder 30 due to internal pressure preferably is
slightly greater than the weight of the power tong T, so that the
tong T will be initially in the upper position of FIG. 1 spaced
from the back-up tong B, but when the jaws 4 grip the tool joint
part 1 to spin the latter into the joint part 2, the tong T is
easily moved downwardly as the joint J is progressively made
up.
From the foregoing it will be apparent that the present invention
provides a simple solution to the problem of relative tong movement
when threaded tool joints of drill pipe are being made up and
broken out. While reference herein to the tool joints of drill pipe
has been used for purposes of disclosing the invention in the
environment of its main utility in the well drilling and completion
field, it will be understood that the invention may also be availed
of in other applications, such as making up casing couplings, if
desired, or otherwise, where the relative movement of one joint
part and another is encountered.
The foregoing description and drawing will suggest other
embodiments and variations to those skilled in the art, all of
which are intended to be included in the spirit of the invention as
herein set forth.
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