U.S. patent number 3,906,820 [Application Number 05/391,295] was granted by the patent office on 1975-09-23 for apparatus and method for spinning pipe.
This patent grant is currently assigned to Spinnerhawk Company. Invention is credited to Ernest D. Hauk.
United States Patent |
3,906,820 |
Hauk |
September 23, 1975 |
Apparatus and method for spinning pipe
Abstract
A pipe spinner and method for spinning pipe used in oil wells.
The pipe is engaged simultaneously by a chain and by friction-drive
rollers. Both the chain and the rollers are driven. The beneficial
results thus achieved include increased torque, and greatly
extended chain life. The chain is a silent chain, and has an
inverse internal portion which mounts around the pipe without any
necessity for latching of jaws or for breaking of the chain.
Tightening of the chain is effected by power cylinders which close
the jaws on which are mounted (a) sprockets for the chain, and (b)
the friction-drive rollers associated with such sprockets.
Inventors: |
Hauk; Ernest D. (Signal Hill,
CA) |
Assignee: |
Spinnerhawk Company (Signal
Hill, CA)
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Family
ID: |
26931318 |
Appl.
No.: |
05/391,295 |
Filed: |
August 24, 1973 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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238069 |
Mar 27, 1972 |
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Current U.S.
Class: |
81/57.17;
173/164; 81/57.34; 166/78.1 |
Current CPC
Class: |
E21B
19/168 (20130101) |
Current International
Class: |
E21B
19/16 (20060101); E21B 19/00 (20060101); B25B
017/00 (); B25B 013/50 () |
Field of
Search: |
;81/57.15,57.16,57.17,57.18,57,57.33,57.34,57.35,57.36,57.38,57.43
;74/245S ;173/163,164 ;166/77.5,78,85 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Smith; Al Lawrence
Assistant Examiner: Smith; James G.
Attorney, Agent or Firm: Gausewitz, Carr &
Rothenberg
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATION
This application is a continuation-in-part of my copending patent
application Ser. No. 238,069, filed Mar. 27, 1972, for
Pipe-Spinning Apparatus and Method.
Claims
I claim:
1. Apparatus for spinning pipe, which comprises:
a. a support,
b. first and second jaws movably mounted on said support,
c. power means to close said jaws with a large amount of force,
d. an elongated closed-loop flexible drive element,
said flexible drive element having an external portion and an
inverse internal portion disposed within said external portion,
said inverse internal portion being adapted to receive and engage
the pipe to be spun,
e. first and second wheels mounted, respectively, on said jaws,
said wheels having extended therearound the return-bent portions at
which said external portion of said flexible drive element connects
to said internal portion thereof,
f. roller means mounted on said jaws to engage the pipe in response
to forcible closing of said jaws by said power means, and to
prevent said flexible drive element or said wheels from being
damaged or worn due to forcible engagement with said pipe in the
vicinity of said wheels; and
g. means to drive said flexible drive element, and thus effect
spinning of said pipe, after said jaws have been closed by said
power means,
said drive means also being connected to effect driving of said
roller means in such direction that said roller means serve as
drive elements for aiding said flexible drive element in spinning
said pipe,
said driving of said roller means being such that said roller means
impart driving torque to said pipe through the regions of
engagement between said roller means and said pipe.
2. The invention as claimed in claim 1, in which said power means
comprise cylinder means and associated piston means, and also
comprise means to introduce pressurized fluid into said cylinder
means.
3. The invention as claimed in claim 1, in which said flexible
drive element is a chain, and in which said wheels are sprocket
wheels meshed with said chain.
4. The invention as claimed in claim 3, in which said chain is a
silent chain, in which said sprocket wheels are shaped to mesh with
the teeth of said silent chain, in which the untoothed bearing
edges of said chain are on the interior side of said inverse
internal portion so that said bearing edges will engage the
exterior cylindrical surface of said pipe when said jaws are
closed, and in which said roller means prevent said chain from
being compressed between said pipe and said wheels.
5. The invention as claimed in claim 1, in which said flexible
drive element has such length that it prevents said jaws from
closing into engagement with each other, said flexible drive
element constituting when said pipe is disposed in said inverse
internal portion the sole means for counterbalancing the force
exerted by said power means, whereby said inverse internal portion
is tensioned greatly and therefore bears with great force against
said pipe.
6. The invention as claimed in claim 1, in which said flexible
drive element is a chain comprising a large number of planar leaf
links the ends of which overlap each other in alternating
relationship, said overlapped ends being pivotally connected to
each other by pivot pins, each of said leaf links having at one
side thereof an untoothed bearing edge disposed at said inverse
internal portion and adapted to forcibly engage the exterior
surface of said pipe without damaging the same, at least some of
said links incorporating protuberances on the side thereof opposite
said untoothed bearing edges, said protuberances forming part of
said drive means recited in clause (g).
7. The invention as claimed in claim 1, in which said jaws are
pivotally mounted on said support, and in which said jaws are
devoid of any latch means for connecting said jaws to each other on
the side of said pipe remote from said support.
8. The invention as claimed in claim 1, in which said roller means
comprise rollers mounted on said first jaw in axial alignment with
said first wheel, in which said roller means further comprise
rollers mounted on said second jaw in axial alignment with said
second wheel, and in which the diameters of said rollers are
sufficiently large that said rollers engage said pipe when said
jaws are closed and therefore relieve the pressures tending to
damage said flexible drive element or said wheels.
9. The invention as claimed in claim 8, in which said diameters of
said rollers are sufficiently large that said flexible drive
element is, at the portion thereof adjacent said wheels, spaced
away from said pipe.
10. The invention as claimed in claim 8, in which said rollers are
connected to said wheels and therefore rotate therewith, whereby
said rollers serve as drive rollers for aiding said flexible drive
element in spinning said pipe.
11. The invention as claimed in claim 1, in which said means to
drive said flexible drive element comprises a power-driven wheel
drivingly engaged with said flexible drive element, and means to
mount said power driven wheel in such manner that the axis thereof
is fixed in position at all times when the apparatus is being
employed to spin pipe having a fixed predetermined diameter.
12. Apparatus for rotating pipe about the longitudinal axis
thereof, which comprises:
a. an elongated flexible drive element adapted to engage a pipe
along a substantial arc of the exterior surface thereof, to thereby
rotate the pipe about the longitudinal axis thereof,
said flexible drive element being a closed loop having an external
portion and an inverse internal portion,
the interior surface of said inverse portion engaging the exterior
surface of said pipe around a major portion of the pipe
circumference,
b. drive roller means adapted to engage said pipe to rotate the
same about the longitudinal axis thereof, said flexible drive
element and said drive roller means engaging said pipe
simultaneously with each other,
said drive roller means engaging said pipe adjacent the return-bent
portions at which said external portion of said flexible drive
element connects to said inverse internal portion thereof,
said return-bent portions being respectively mounted around
wheels,
said roller means comprising rollers drivingly related to said
wheels for driving thereby, and
c. means to forcibly drive said flexible drive element and said
rollers to thus effect rotation of said pipe about the longitudinal
axis thereof due to the conjoint operation of said flexible drive
element and said rollers,
said drive means being such that said flexible drive element
imparts driving torque to said pipe through the arc of engagement
between said flexible drive element and said exterior surface, said
drive means also being such that said rollers impart driving torque
to said pipe through the regions of engagement between said rollers
and said exterior surface.
13. The invention as claimed in claim 12, in which said rollers are
coaxial with said wheels and are rigidly connected thereto for
conjoint rotational movement.
14. The invention as claimed in claim 13, in which the diameters of
said rollers are sufficiently large to prevent damage to said
flexible drive element or said wheels due to forcible engagement
with said pipe.
15. The invention as claimed in claim 12, in which said flexible
drive element is a silent chain.
16. A pipe-spinning apparatus for spinning pipe at the wellheads of
oil wells, which comprises:
a. a movable support,
b. first and second jaws pivotally mounted on said support for
pivotal movement in such manner that the distal ends of said jaws
move toward and away from each other as said jaws close and
open,
said distal ends being so related to each other that, unless
restrained, they would touch upon closing movement of said
jaws,
c. piston and cylinder means connected to said jaws to forcibly
close the same and thereafter open them,
d. first and second "silent-chain" sprocket wheels rotatably
mounted, respectively, at end portions of said first and second
jaws,
e. a silent chain having an external portion and an inverse
internal portion,
said external and internal portions connecting to each other at
return-bent portions which bend around and mesh with said first and
second sprocket wheels,
said internal portion being adapted to receive the pipe to be
spun,
f. a drive sprocket wheel mounted on said movable support and
meshed with said chain,
the length of said chain being such that when said inverse chain
portion encompasses a pipe of predetermined diameter said jaws may
not be closed sufficiently far to cause said distal ends thereof to
touch each other,
g. means mounted on said support to drive said drive sprocket
wheel,
h. first and second roller means respectively mounted at said end
portions of said first and second jaws,
said first and second roller means being respectively coaxial with
said first and second sprocket wheels,
said roller means having diameters sufficiently large to prevent
said return-bent chain portions from being compressed between said
pipe and said first and second sprocket wheels, and
i. means provided to drivingly connect in positive manner said
first roller means to said first sprocket wheel, and said second
roller means to said second sprocket wheel,
whereby said roller means constitute friction-drive rollers which
cooperate with said inverse internal portion in spinning said
pipe.
17. The invention as claimed in claim 16, in which means are
provided to adjust the position of the axis of said drive sprocket
wheel, and to lock said axis in adjusted position, whereby to adapt
the apparatus for spinning pipes of different diameters.
18. The invention as claimed in claim 16, in which additional
sprocket wheels for said silent chain are respectively mounted at
the pivot axes of said first and second jaws, said additional
sprocket wheels being meshed with said chain.
19. A method of rotating pipe adjacent the wellhead of an oil well,
to thereby make or break threaded joints between coaxial pipe
sections, which comprises:
a. wrapping a section of a flexible drive element around at least a
major portion of the circumference of said pipe to be rotated, and
in engagement with the exterior surface of said pipe,
b. engaging roller means with said exterior surface of said pipe in
the general region of said flexible drive element,
c. creating great tension in said flexible drive element to force
it into pressure engagement with said exterior surface,
d. creating large bearing pressure between said roller means and
said exterior surface, and
e. simultaneously driving both said flexible drive element and said
roller means to thereby rotate said pipe,
said driving of said flexible drive element imparting driving
torque to said pipe through the area of engagement between said
flexible drive element and said exterior pipe surface,
said driving of said roller means imparting driving torque to said
pipe through the area of engagement between said roller means and
said exterior pipe surface.
20. Apparatus for rotating about the longitudinal axis thereof a
pipe which has a substantially cylindrical exterior surface, which
apparatus comprises:
a. a support,
b. first and second jaws mounted on said support and movable
between an open position in which said first and second jaws are
relatively remote from each other and a closed position in which
said first and second jaws are relatively close to each other,
c. an elongated closed-loop flexible chain,
said chain comprising a large number of planar leaf links the ends
of which overlap each other in alternating relationship, and pivot
pins pivotally connecting said overlapped ends together, said leaf
links being in a relatively high density such that there is a close
spacing between adjacent links at the central portions thereof
intermediate adjacent ones of said pivot pins,
said leaf links having on one side thereof untoothed bearing edge
portions adapted to forcibly engage the substantially cylindrical
exterior surface of the pipe without damaging the same, and having
protuberance means on the other side thereof,
d. wheel means comprising a plurality of wheels including first and
second wheels mounted, respectively, on said first and second
jaws,
said chain being mounted around said wheel means in such manner
that, when said jaws are in said closed position, there is an
external chain section, an inverse internal chain section disposed
within said external section, and junction regions between said
external and internal chain sections return-bent and extending
respectively around said first and second wheels,
said internal chain section being adapted to receive said pipe and
being so oriented that said untoothed bearing edge portions of said
leaf links in said internal chain section engage said substantially
cylindrical exterior surface of said pipe,
said internal chain section engaging, when said jaws are in said
closed position, said substantially cylindrical exterior surface of
said pipe about a majority of the circumference thereof but not
about the full circumference,
e. rollers mounted on said jaws to engage said substantially
cylindrical exterior surface of said pipe adjacent said junction
regions,
said rollers having peripheral surfaces which are closer to said
exterior pipe surface than are said leaf links and said first and
second wheels so that said rollers engage said exterior pipe
surface and prevent said leaf links and said first and second
wheels from being damaged or worn due to forcible compression of
said leaf links between said exterior pipe surface and said first
and second wheels,
f. power means selectively operable for moving said jaws to said
open position thereof and for moving said jaws to said closed
position thereof, such that said internal chain section so engages
said substantially cylindrical surface of said pipe, and for
causing a large tension to be created in said chain, thereby
causing said untoothed bearing edge portions of said leaf links in
said internal chain section to engage with great force said
substantially cylindrical exterior surface of said pipe so
received,
said jaws operating, when in said closed position, to hold said
pipe in position in said internal chain section, and
g. means to drive said chain, and thus effect rotation of said pipe
about the longitudinal axis thereof, when said jaws are in said
closed position and said chain has thus been tensioned,
said means to drive said chain including at least one of the wheels
in said wheel means,
said one wheel incorporating protuberance means meshing with said
protuberance means of said leaf links on said other side of said
leaf links,
said means to drive said chain further including power means for
rotating said one wheel for causing said protuberance means thereof
to react with said protuberance means of said leaf links on said
other side of said leaf links and thus advance said chain.
21. A method of rotating cylindrical pipe sections adjacent the
wellhead of an oil well, to thereby make or break threaded joints
between coaxial pipe sections, which method comprises:
a. providing a closed-loop flexible drive chain comprising a large
number of planar alternated leaf links the ends of which are
pivotally connected to each other by pivot pins, such leaf links
having at one side thereof untoothed bearing edge portions adapted
to forcibly engage the pipe surface without damaging the same, and
having at the other side thereof protuberance means adapted to be
engaged by a driving means,
b. then causing said chain to assume a shape in which it has an
external section, an inverse internal section disposed within said
external section, and bent portions between said external and
internal sections, and has said untoothed bearing edge portions of
said leaf links on the inner side of said internal chain
section,
c. disposing a cylindrical pipe section in said internal chain
section,
d. causing said chain to engage a majority of the circumference of
said pipe section, but less than the entire circumference thereof,
in such manner that said pipe section is constrained by said
internal chain section and prevented from moving out of the same,
and creating great tension in said chain to thereby cause said
untoothed bearing edge portions of said leaf links in said internal
chain section to forcibly engage said pipe section about a majority
of the circumference thereof,
e. engaging and moving said protuberance means of said leaf links
to thus drive said chain with consequent rotation of said pipe
section about the longitudinal axis thereof,
said step of engaging and moving said protuberance means being
performed by causing protuberance means on at least one
power-operated drive wheel to engage and drive said protuberance
means on said leaf links, and
f. preventing from forcibly engaging said pipe section said bent
portions of said chain which connect said external chain section
and said internal chain section.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to the field of apparatus and methods for
rotating substantially cylindrical objects, particularly drill
pipe, drill collars, casing, etc. The word "cylindrical" is
employed in this specification in its ordinary or common sense,
namely to define objects which have a circular or substantially
circular exterior cross-sectional shape.
2. Description of Prior Art
The cited copending application sets forth much background, and
specifies much prior art, all relating to the long-standing effort
to replace the dangerous and unsatisfactory spinning chain. The
cited application also describes and claims an apparatus and method
which are greatly superior to those of the prior art. In the
present application, there are described and claimed an apparatus
and method which have the same superiorities over the prior art
and, in addition, are characterized by an even greater driving
torque and by a much extended chain life.
There are large numbers of prior-art pipe-spinner devices wherein
the pipe is engaged and driven by a chain (or other flexible drive
element) only, or by friction-drive rollers only. There is no such
device known to applicant wherein both a chain (or other flexible
drive element) and friction-drive rollers simultaneously engage and
drive the pipe. Such simultaneous use of the chain and of
friction-drive rollers achieves the surprising benefit of
increasing the drive torque, as well as increasing greatly the
chain life. The torque increase and the life increase occur without
losing any of numerous benefits of chain-type devices over devices
which have rollers only.
In order to be highly practical and fast-acting, a pipe spinner
should operate from only one side of the pipe. From such one side,
the spinner should grab the pipe, then spin it, then let loose. The
apparatus described herein and in the cited copending application
are of such type, and are to be contrasted with prior art apparatus
of types wherein the chain had to be broken each time the tool was
mounted on the pipe, or wherein a latching means had to be closed
on the side of the pipe remote from the main portion of the
spinning apparatus, or wherein there were no power-operated jaws,
or wherein the pipe was not engaged directly. Some prior art tools
of these last-mentioned types are shown in the following patents:
U.S. Pat. Nos. 1,760,167; 1,805,007; 1,925,970; 2,460,671; and
2,573,212.
SUMMARY OF THE INVENTION
The present invention provides pipe-engaging rollers at the ends of
power-operated jaws which close toward the pipe with great force.
Furthermore, there is provided a chain having an inverse internal
portion, the ends of which bend around sprockets located at the jaw
ends. The diameters of the rollers are sufficiently large that they
engage the pipe and relieve the loads on the bent chain portions
which extend around the indicated sprockets. Such bent portions
are, therefore, not compressed between the sprockets and the pipe,
despite the great force of the jaws. Accordingly, the lives of the
chain and sprockets are very greatly extended. The chain should be
a silent chain, as described and claimed in the cited patent
application, to achieve numerous advantages relative to (for
example) gripping the pipe without damaging the same, and relative
to achievement of a desirable clutching action when the joint
seats.
According to one important aspect of the present invention, the
rollers are connected to the sprockets in such manner that the
rollers are forcibly and positively driven thereby. The rollers are
thus friction-drive rollers which engage and drive the pipe. The
friction between rollers and pipe is great, because of the great
closing power created in the jaws. The rollers thus engage the pipe
and friction-drive it at a plurality of points about the pipe
circumference, and the silent chain engages the pipe and
friction-drives it at a large number of other points around such
circumference. There should be no teeth on either rollers or chain,
all gripping being instead frictional and resulting from the
forcible closing of the jaws and from the resulting great tension
created in the chain.
Since there is no need to break the chain when the tool is mounted
on the pipe, or to latch the jaws together, the apparatus and
method are operated on only one side of the pipe and are therefore
extremely practical and fast acting. The described combination of
power-closed jaws, friction-drive rollers, and silent chain having
an inverse internal portion achieves many advantages. Such
advantages include (for example) high torque, long chain life,
great adaptability to fit on pipes of different diameters, ability
to grip effectively on oily and dirty pipes, minimized damage to
the pipe, and ability to work on surfaces which are not perfectly
cylindrical. Surprisingly, the present tool with driven rollers
creates more torque than the same tool with no rollers--this
despite the fact that roller-type tools normally create less drive
torque than do chain-type tools.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an isometric view of the present apparatus, said view
corresponding substantially to FIG. 1 of the above-cited patent
application, but showing the friction-drive rollers mounted in the
jaws and also showing a different form of suspension;
FIG. 2 is a bottom plan view, corresponding generally to FIG. 4 of
the cited application, and showing the present apparatus when in
the pipe-gripping position;
FIG. 3 is a vertical sectional view on line 3--3 of FIG. 2 and
which corresponds generally to FIG. 6 of the cited application;
FIG. 4 is a horizontal sectional view which corresponds generally
to FIG. 7 of the cited application, the jaws being shown in an open
position permitting introduction of the pipe;
FIG. 5 is a horizontal section view on line 5--5 of FIG. 3 and
corresponding generally to FIG. 8 of the cited application, the
jaws being shown closed on the pipe;
FIG. 6 is an enlarged fragmentary vertical sectional view on line
6--6 of FIG. 5, and illustrating the drive means between the
sprockets and the associated friction-drive rollers; and
FIG. 7 is an enlarged fragmentary isometric view illustrating a
portion of the silent chain.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Except as specifically stated in the present specification, the
apparatus and method described herein are identical to those
described in the above-cited patent application Ser. No. 238,069.
Said application Ser. No. 238,069 is hereby incorporated by
reference herein, as though set forth in full.
To summarize briefly the various basic components of the present
apparatus, an elongated closed-loop flexible drive element 33 is so
mounted that it has an external portion 33a, an inverse internal
portion 33b, and two return-bent portions 33c which connect the
external portion to the internal portion.
The flexible drive element should be a silent chain as described
and claimed in the cited patent application. Such chains are well
known in other arts, one example (suitable for use as the flexible
drive element 33) being given by U.S. Pat. No. 3,661,025 for a
Silent Chain and Method of Assembly Thereof, which patent is hereby
incorporated by reference herein as though set forth in full.
"Silent chain" is a recognized term for an inverted-tooth chain
made up of a large number of corresponding planar leaf links 36 the
ends of which overlap each other in alternating relationship as
shown in FIG. 7. Each leaf link has an inner bearing edge 37
adapted to engage the pipe 34, and also has at each end thereof
(and on the side opposite edge 37) a pair of sprocket teeth 38
which are shaped to mesh with the various sprocket wheels. The
bearing edges 37 of the various links are shown as being
substantially straight, but they may also be slightly concave in
order to conform more closely to the exterior surface of pipe
34.
In the illustrated silent chain 33, the various leaf links 36 are
disposed in pairs, such as 36a and 36b, which are coextensive,
parallel and in surface contact with each other. Large numbers of
such pairs are disposed in what may be termed layers, in the
alternating relationship shown in FIG. 7. Pivot pins 39 extend
through the end portions of the leaf links to hold the chain
together in pivotal relationship.
The silent chain 33 (and the sprocket wheel teeth) are preferably
constructed in accordance with American Society of Automotive
Engineers Standard B29.2. Such chain is well known in industry,
being desirable for various purposes because of its silent
operation, strength, durability, etc. In accordance with the
present apparatus and method, the relatively silent operation of
the chain is not a factor, the purpose being instead to create
large bearing areas at the inner leaf edges 37 and which engage the
external cylindrical surface of the pipe 34 to be spun.
When a chain is employed having the indicated leaf edges 37, and
the large bearing area, it is not necessary to provide teeth on the
inner surfaces of the chain (the pipe-engaging surfaces thereof),
so that there is a minimum possibility of damage to the pipe.
Furthermore, when no pipe-engaging teeth are employed, the chain
may more readily slip relative to the pipe when the joint bottoms
out.
The use of the silent chain in combination with the very large
jaw-closing pressures indicated below, permit the spinning
apparatus to create a sufficient torque to spin large pipes at high
speed, despite the presence of water, oil, etc., on the pipe. One
advantage of the silent chain is that it is substantially incapable
of being stretched. Furthermore. it is a primary advantage that the
pipe is spun without any substantial damage thereto.
The chain 33 extends around sprocket wheels 24 which are fixedly
mounted at the front end of the main housing of the apparatus (such
housing constituting a "support" for various components of the
apparatus). Pivotally connected to the main housing at the axes of
sprocket wheels 24 are the jaws 16a and 17a, such jaws respectively
corresponding to jaws 16-17 of the cited application except as
specified hereinafter. The jaws have sprocket wheels (described
below) at the outer ends thereof and around which the chain 33
bends at the return-bent portions 33c.
When jaws 16a-17a are in the opened condition of FIGS. 1 and 4, the
apparatus may be mounted around a vertical pipe 34 to be spun.
Then, the jaws are closed with much force, for example to the
position of FIGS. 2 and 5, thereby creating a large amount of
tension in the inverse internal portion 33b to cause such portion
to frictionally engage the exterior pipe surface with great bearing
pressure. The inverse internal portion engages the exterior pipe
surface about a majority of the circumference thereof but not about
the full circumference. When the jaws are thus in closed condition,
they maintain the pipe in position in the inverse internal portion
of the chain.
Opening and closing of jaws 16a-17a is effected by power means best
shown in FIGS. 2 and 3, namely, pneumatic cylinders 61 the pistons
of which connect to the jaws through cranks and linkages as
described in detail in the cited application. The cranks and
linkages include crank arms 56 which are fixedly associated with
the jaws 16a-17a.
When the jaws are closed, the distal ends thereof do not touch each
other (and thus act as mutual stops). Instead, the chain 33 acts as
the sole means to limit the degree of jaw closing, the result being
that closing of the jaws creates much tension in the chain. The
jaws are so constructed that, if there were no chain, the jaw ends
would (when the jaws are closed) touch each other.
After the jaws are closed to grip the chain portion 33b on pipe 34,
the chain is driven in order to effect rapid spinning of the pipe.
Such driving is effected by a pneumatic motor 42 which operates
through a gear box 47 to rotate a shaft 51 (FIGS. 3 and 4) on which
is mounted the drive sprocket 32 for chain 33. Thus, when a control
valve is operated to admit air into the motor 42, the shaft 51 is
driven to thus drive the sprocket wheels 32 and thereby drive chain
33 to rotate pipe 34.
The motor 42 and gear box 47 are movable toward and away from the
pipe 34, thus moving the axis of shaft 51 and of sprocket wheel 32.
Such movement is not effected except when it is desired to adapt
the apparatus for driving a substantially different diameter of
pipe 34. To achieve the indicated adjustment, a chain guide and
lock element 41 are shifted in response to rotation of an
adjustment screw 52. After the adjustment is completed, lock screws
48 (which extend through a flange portion of the gear box 47, and
are threaded into element 41) are tightened in order to lock
element 41 (and thus elements 42, 47 and 51) in position. In order
that the described adjustment may occur, the upper portion of the
housing of the apparatus is suitably slotted, as illustrated, to
receive the lock screws.
The apparatus is suspended, adjacent the wellhead of an oil well,
by means of an inverted V-shaped suspension bar 110 the lower ends
of which connect to the housing of the apparatus. At the upper or
apex portion of bar 110 is provided a mounting means 111 by which
the bar may be connected to the lower link of a suspension chain
112. The mounting means 111 is so constructed that the chain may be
connected at different axial points therealong, thus permitting
balancing of the spinning apparatus in generally a horizontal
condition.
In order to facilitate manipulation of the apparatus, suitable
handles 113 are provided below each jaw 16a-17a as illustrated
(relative to jaw 16a) in FIG. 1.
DETAILED DESCRIPTION OF THE FRICTION-DRIVE ROLLERS AND ASSOCIATED
SPROCKET WHEELS
As best shown in FIGS. 3 and 6, each jaw 16a-17a is enlarged at the
outer portion thereof in order that it may incorporate two
friction-drive rollers 116 and one sprocket wheel 117. Since the
elements at the outer ends of the two jaws 16a-17a are identical,
only the elements incorporated in jaw 16a are shown and described
in detail.
Referring to FIG. 6, the two rollers 116 are disposed on opposite
sides of (above and below) the sprocket wheel 117, all of the
elements 116 and 117 being mounted coaxially of each other on a
vertical shaft. More specifically, such shaft is illustrated as
being bolt 118 which extends through collars 119 welded on the
upper and lower walls of the housing portion of jaw 16a, there
being nuts 121 provided to maintain bolt 118 fixedly in position.
Mounted around bolt 118, between the upper and lower housing walls
of the jaw, is a sleeve 122 around which are provided a plurality
of sets of antifriction bearings (for example, needle bearings)
123. The rollers 116 and sprocket wheel 117 are mounted in
encompassing relationship to such bearings 123 in order that such
elements 116-117 will rotate freely relative to the shaft or bolt
118.
Sprocket wheel 117 (and the other sprocket wheels) is of the type
conventionally employed with a silent chain, having vertical teeth
which mesh with the tooth portions of the chain 33 as described in
the cited patent application and also in said U.S. Pat. No.
3,661,025. Each sprocket wheel may be termed a "silent chain"
sprocket wheel.
It is pointed out that the teeth of the silent chain do not engage
the pipe 34, engagement instead being effected at a multiplicity of
untoothed bearing edges as described above. As is known and
conventional in many silent chains, guiding of the chain is
effected by means of guide links which pass through a
circumferentially grooved central region of the sprocket wheel 117.
Such guide links are indicated at 124 in FIG. 6, and are extended
through the circumferential groove 126 in wheel 117. The other
sprockets of the apparatus have similar circumferential grooves for
reception of the guide links 124.
As shown in FIG. 6, the cylindrical peripheral surfaces of rollers
116 are in direct bearing engagement with the exterior cylindrical
surface of pipe 34. Such rollers 116 have diameters sufficiently
great to insure that neither the chain nor the sprocket wheels will
be damaged due to the pressure engagement with the pipe 34. Stated
more specifically, the roller diameters are sufficient that the
return-bent portions 33c of chain 33 will not be crushed or
compressed between sprocket wheels 117 and the exterior pipe
surface. It has been found that, if such crushing or compression is
permitted to occur, it results in "brinelling" of the chain links
and/or of the sprocket wheels, with consequent stiffening of the
chain and reduction in chain life.
As an example, in the illustrated embodiment, a small gap (for
example, 0.030 inch) is provided at 127 (FIG. 6) between each
return-bent chain portion 33c and the exterior pipe surface. The
presence of such gap assures that even substantial wearing on the
rollers, so as to reduce the diameters thereof, will not cause the
chain 33 to be compressed between sprocket wheels 117 and the pipe
to thereby cause wear and stiffening of the chain.
It is emphasized that each gap 127 is only present at a relatively
small region immediately between sprocket wheel 117 and the pipe,
and that the chain portion 33b is in direct engagement with a major
portion of the circumference of the pipe. Thus, there are two
important areas of frictional engagement between the drive elements
and the pipe 34. One of such areas is at the rollers 116, and the
other of such areas (which is much larger than the first) is along
a major portion of the circumference of the pipe and at which the
silent chain frictionally engages the pipe.
Stated in another manner, the chain frictionally engages the pipe
along a long arc of the circumference thereof, whereas the
friction-drive rollers frictionally engage the pipe at about (or
between) the ends of such long arc. The word "circumference" is
presently employed to denote only one circumferential region along
the length of the pipe.
Applicant has discovered that, if the rollers 116 are not driven
but instead are permitted to rotate freely in the manner of
antifriction bearings for the pipe 34, then the amount of drive
torque created by the spinning apparatus is drastically reduced.
If, on the other hand, the rollers are positively driven with or by
the sprockets 117, then the drive torque created by the present
spinning apparatus is increased in comparison to the torque which
would be created if no rollers were employed. Such an increase was
not to be expected, particularly because the rollers are only in
line contact with the pipe whereas the chain portion (which was
lifted, by the rollers, off the pipe) was in surface contact with
the pipe.
To summarize, therefore, the presence of the driven rollers 116
creates two major benefits relative to the construction described
in the cited application, wherein no such rollers are employed.
These benefits are increased drive torque and greatly increased
chain life.
The driving of the rollers 116 on each jaw 16a-17a is effected by
means of drive pins 128 which extend into registered apertures in
the ends of the sprocket and of the rollers. Since each sprocket
117 is driven by the chain 33 (which chain is in turn driven by the
drive sprocket wheel 32 in response to operation of motor 42 and
gear box 47), and since the rollers 116 are connected to the
sprocket 117 by means of drive pins 128, it follows that the
rollers 116 are driven positively, and operate as friction-drive
rollers for the pipe 34.
DESCRIPTION OF THE METHOD
The jaws 16a-17a are first opened by operation of the pneumatic
cylinders 61, for example to the position shown in FIGS. 1 and 4.
The amount of opening is enough to permit the apparatus to be swung
toward the pipe 34 so that the pipe enters the space between the
return bent portions 33c of the chain and becomes largely
surrounded by the inverse internal portion 33b thereof.
The cylinders 61 are then operated to close the jaws 16a-17a, with
great force, for example to the positions shown in FIGS. 2 and 5.
The jaws do not close to positions such that they engage each other
and serve as mutual stops, the degree of closing being instead
determined by the length of the chain. Thus, the jaws close until
the chain tension is so great that it counter-balances the
jaw-closing force. The described jaw closing and chain tension
cause strong pressure engagement between the rollers 116 of the
pipe, and between the inverse internal chain portion 33b and the
pipe. Such pressure engagements create great friction, without
damaging the pipe, which friction is operative to spin the pipe
after the motor 42 is started to drive (by means of gear box 47)
the shaft 51 and thus the drive sprocket wheel 32 and chain 33.
Driving is effected until the desired joint is either made or
broken, at one end of the pipe 34, following which the cylinders 61
are operated to open the jaws and permit the operation to be
repeated with a different length of pipe.
As described in detail above, the driving of the chain effects
driving of the rollers 116 so that they operate as friction-drive
rollers and cooperate with the inverse internal chain portion 33b
in driving and spinning the pipe without damage thereto.
The apparatus may operate on pipes of slightly different diameters,
without effecting any adjustment in the position of the drive
sprocket wheel 32. When a pipe of substantially different diameter
is to be driven, the position of the axis of wheel 32 is adjusted
as described heretofore and in the cited application. Briefly, this
adjustment is effected by loosening the lock screws 48, turning the
adjustment screw 52 until the position of the shaft 51 is such that
the chain is adjusted to the desired length, and then re-tightening
the screws 48. The method is then repeated in the manner described
above but with the pipe of substantially different diameter.
If desired, very high torques may be created with the present
apparatus, particularly if the silent chain is caused to be very
wide and if there is a very large gear reduction between the
pneumatic motor 42 and the drive sprocket wheel 32. It is also
pointed out that the pneumatic motor 42 could be replaced by
hydraulic means in order to increase torque capabilities.
The foregoing detailed description is to be clearly understood as
given by way of illustration and example only, the spirit and scope
of this invention being limited solely by the appended claims.
* * * * *