US3739434A

US3739434A - Clamp for well pipe

Info

Publication number: US3739434A
Application number: US00195091A
Authority: US
Inventors: E Wheeler
Original assignee: Individual
Current assignee: Individual
Priority date: 1970-10-30
Filing date: 1971-11-03
Publication date: 1973-06-19
Anticipated expiration: 1990-06-19

Abstract

A clamp for holding a string of pipe suspended in a well. The clamp is mounted upon a flat plate which is secured to the well casing to prevent it from rotating. The plate has a throat at one side to receive a pipe suspended in the well and verticallysplined jaws form a V-notched abutment at the crotch of the throat. A clamp arm having a horizontally-splined head is pivotally mounted upon the plate to be pulled against a pipe in the throat to engage the pipe between the jaws and the head. A cammed pull rod connecting with the arm engages a cam seat on the plate to lock the jaws and head onto the pipe and prevent it from slipping and rotating in the clamp.

Description

A United States Patent 191 Wheeler CLAMP FOR WELL PIPE [76] Inventor: Eugene F. Wheeler, Franktown,

Colo. 80116 [22] Filed: Nov. 3, 1971 [21] Appl. No.: 195,091

Related US. Application Data [63] Continuation-impart of Ser. No. 85,360, Oct. 30,

1970, Pat. No. 3,637,011.

[52] US. Cl. 24/249 DP, 166/77.5 [51] Int. Cl E2lb 33/03 [58] Field of Search 24/243 DP, 248 B,

24/248 E, 248 R, 249 LL, 249 WL, 249 PC, 249 R, 249 PP, 249 DP, 263 DT, 263 LL, 263 DO, 263 D, 263 DL; 166/775; 29/283 June 19, 1973 Primary Examiner-Donald A. Griffin Attorney- Horace B. Van Valkenburgh and Frank C. Lowe [57] ABSTRACT A clamp for holding a string of pipe suspended in a well. The clamp is mounted upon a flat plate which is secured to the well casing to prevent it from rotating. The plate has a throat at one side to receive a pipe suspended in the well and vertically-splined jaws form a V-notched abutment at the crotch of the throat. A clamp arm having a horizontally-splined head is pivotally mounted upon the plate to be pulled against a pipe in the throat to engage the pipe between the jaws and the head. A carnmed pull rod connecting with the arm engages a cam seat on the plate to lock the jaws and head onto the pipe and prevent it from slipping and rotating in the clamp.

4 Claims, 8 Drawing Figures PATENTEU Jun: 9 ma SHEEIIUFS CLAMP FOR WELL PIPE This application is a continuation-in-part of my application filed Oct. 30, 1970, Ser. No. 85,360, now U.S. Pat. No. 3,637,011, issued Jan. 25, 1972, to disclose and to claim additional subject matter within the scope of the invention.

The present invention relates to clamps for holding a string of pipe suspended in a well while the pipe is being installed in, or removed from, the well. As such, the invention will be called a clamp for well pipe.

Whenever pipe is being installed in or removed from a well, it is necessary to hold the depending string of pipe at the head of the well to protect it against falling into the well and also to hold it against turning when couplings and pipe sections above the well head are being screwed onto or off from the pipe string. Various types of apparatus are provided for this purpose. In large, deep wells where the pipe string is heavy, regular drilling rigs having rotating tables, slips and tongs are necessary to hold the string of pipe. In small, comparatively shallow wells, such as water wells, the string of pipe is held by hand tools such as Stillson wrenches. This is usually satisfactory because the weight of the string is not excessive. However, sooner or later, the wrench will slip causing an expensive fishing job if not a more serious accident.

Several types of clamps have been developed for holding a string of pipe in a small well, and the patent to B. G. Bjalme, U.S. Pat. No. 2,854,216, issued Sept. 30, I95 8, is exemplary of this development. While such devices are an improvement over Stillson wrenches, they are not completely satisfactory because they are awkward to use.

There is a real and definite need for an improved and simplified clamp for holding well pipe, and the present invention was conceived and developed with such need in view. The invention comprises, in essence, a clamp for well pipe which is formed upon a base plate, which, in turn, is mounted and secured to the head or top of the well casing. The clamp is a quick-acting arrangement of gripping arms for holding and releasing the end of a string of pipe as the string is being made up and lowered into the well, as will be hereinafter described.

An object of the present invention is to provide a novel and improved clamp for holding a string of pipe in a well which may be mounted upon the head of the well casing and secured thereto against turning, so that the operator may screw on, or off, other pipe sections above the well head, and tightly make up pipe sections fitted onto the string or break connections rusted together when pipes are to be disconnected, all without the necessity of holding the clamp.

Another object of the invention is to provide a novel and improved clamp for well pipe which, once mounted upon a casing head, can quickly and solidly grip the top of a string of pipe suspended in the well and also quickly release the string when necessary.

Other objects of the invention are to provide a novel and improved clamp for well pipe which is a simple, compact, economical rugged and reliable structure.

With the foregoing and other objects in view, all of which more fully hereinafter appear, my invention comprises certain constructions, combinations and ar rangements of parts and elements as hereinafter described, defined in the appended claims and illustrated, in preferred embodiment in the accompanying drawing in which:

FIG. 1 is an isometric view of a first embodiment of the improved well clamp mounted upon the head of a well casing and holding the top of a string of pipe sus pended in the well.

FIG. 2 is a plan view of the arrangement shown at FIG. I with broken lines indicating parts hidden from view, and an alternate position of a locking member.

FIG. 3 is a transverse sectional view as taken from the indicated line 3-3 at FIG. 2, but on an enlarged scale, without the clamp holding pipe as shown at FIGS. 11 and 2 and with a connective pin normally hidden from view being shown in broken lines.

FIG. 4 is an end view partially in section, as taken from the indicated offset line 4-4 at FIG. 2, but on an enlarged scale.

FIG. 5 is an isometric, exploded view of the components forming the clamp as taken from the side opposite the showing at FIG. 1, as from the indicated arrow 5 at FIG. 1.

FIG. 6 is a plan view of a second embodiment of the improved well clamp.

FIG. 7 is a side view of the well clamp as taken from the indicated arrow 7 at FIG. 6.

FIG. 8 is an isometric view of the well clamp as taken generally from the indicated arrow 8 at FIG. 7.

Referring first to FIGS. 1 to 5 of the drawings, the improved clamp C is formed upon a rectangular base plate 20 which is adapted to set upon and to be secured to the end, or head of a well casing W. The well casing is ordinarily a pipe varing from 4 to 8 inches in diameter and the base plate 20 is of a length sufficient to overlie the larger casing as well as the smaller, and of a width to partially overlie either the larger or smaller casing. This base plate is formed with a throat 21 which extends from the center of one side edge of the plate approximately halfway into the base plate and which is of sufficient width as to receive a well pipe P varying from 1 to 3 inches in diameter. A clamping means is located at this throat as will be described.

A means is provided to secure this base plate 20 upon the head of the casing which includes three spaced lugs 22 depending from the underside of the base plate 20B,

one being at the side edge opposite the throat 21 and the other two being at the ends of the base plate adjacent to the throat edge as best indicated by the dotted lines at FIG. 2. A tapped hole in each lug carries a bolt 23, and this triad of bolts are extended to the walls of the well casing W to securely engage the casing and place the throat 21 approximately over the axial center of the casing as illustrated. These lugs 22 and bolts 23 are preferably fairly heavy members to resist twisting forces upon the casing when a pipe or coupling is being screwed onto or off from the pipe string P held in the clamp C.

The pipe gripping members at thethroat 21 include a comparatively thick body 25 having gripping jaws 2b in the form of a V-notch. This body is securely affixed to the top surface of the base plate 20 as by a bolt 27, FIG. 3, with the V-notch being at the crotch of the throat 21, The body 25 is also positioned against a saddle at the center of an upstanding abutment bar 28 welded to the surface of the base plate 20 as at 2@'. The jaws 26 are ridged with gripping splines 29 extending across the jaws to be vertical when the clamp is set upon the well casing W. Thus, whenever a pipe P is wedged into the notch formed by the jaws 26, the grip of the splineswill prevent the pipe P from rotating. The

pipe gripping members also include a clamp head 30 which is carried upon a clamp arm 31. This arm 31, pivoted upon the base plate body 20, will push the head 30 against the pipe P. Transverse splines 32 are formed upon the face of this head 30 to be horizontal when the clamp is set upon the well casing W. Thus, whenever a pipe P is pushed into the notch, formed by jaws 26, by the head 30, the splines 32 will grip the pipe to prevent it from sliding downwardly in the clamp to supplement the grip of the jaw splines 29 which keep the pipe from turning. The clam head 30 is secured to the arm 31 by machine screws as at 33 shown in FIG. 3.

The abutment bar 28, formed as a spreading V has one end curved on a reverse curve to form a pivot seat 34 to hold one end of the arm 31. The other end of the abutment bar 28 is also curved, on a reverse curve, and slotted to form a seat 35 for a lock cam, as hereinafter described.

The pivot end of the clamp arm 31 is formed as a clevis 36 which is adapted to straddle the abutment bar 28 with the eyes 37 of the clevis receiving a pivot pin 38 which lies against the pivot seat 34 of the abutment bar 28. To permit the clevis to straddle the abutment bar with one head of the clevis lying against the surface of the body 25, the abutment bar is slotted, as at 39, at the pivot seat portion 34, as best illustrated at FIG. 5. The other head of the clevis overlies the top edge of the abutment bar 28, as best illustrated at FIG. 1. This pivot pin is of a length in excess of that required to straddle the eyes of the clevis and the lower portion will extend into a socket hole 40 in the base plate 20 as shown in broken lines at FIGS. 3 and 5. This pin may be pressed, screwed or welded into the socket hole to make a permanent connection if desired.

The opposite end of the clamp arm 31 is formed as a handle 41 to facilitate an operator gripping the same and pulling the clamp head 30 against a pipe P and to hold the arm in this position until it can be locked by a cam 42. The cam 42, which engages the cam seat 35 as will be described, includes a threaded pull rod 43 which extends through a hole 44 in the clamp arm adjacent to the handle. The pull rod is held against the clamp arm by a nut 45, which is preferably a jam nut to prevent it from turning once the apparatus is adjusted for a given size pipe. The fit of the pull rod 43 in this hole 44 is comparatively loose to facilitate moving the cam 42 upon and away from its seat as will be described.

The cam 42 also includes a pair of aligned, discshaped lobes 46 which are spaced apart to place the pull rod 43 between them and which are secured together by a head 47 at one edge of the lobes. A handle 48 is connected to the head to rotate the lobes as will be described. The end of the pull rod 43, which lies between the lobes 46, is formed with an eye 49 as shown in section at FIG. 4 and in broken lines at FIG. 2, and a pivot pin 50 extends through the lobes at an eccentric position and through the eye to connect the pull rod to the lobes. The eccentric position of the pin 50 through the lobes 46 is such that the handle 48 extends away from the clamp C when the cam is loose and the lobes are not engaging the seat 35, as shown in broken lines at FIG. 2, and is such that the handle 48 rests against the abutment bar 28 when the cam is locked as shown in solid lines at FIGS. 1 and 2.

The cam seat 35, at the end of the abutment bar, is formed with a central slot 51 through which the pull rod 45 extends whenever the lobes 46 engage the seat 35. The seat 35 is curved or dished slightly to prevent the cam lobes 46 from slipping out of position whenever the cam is tightened and locked to pull the arm 31 against a pipe. However, the seat is sufficiently flat as to permit the cam lobes to be removed from the seat whenever they are rotated to a loose, unlocked position. When the cam is removed from the seat it is possible to swing the arm 31 and the cam 42 connected thereto completely out of the way, as when the pipe is to be pulled out of the well.

The use of this clamp is simple. When a string of pipe is to be lowered into or pulled out of a well, and sections of pipe must be added or removed from the string, the pipe clamp is set upon the top of the well casing W which ordinarily extends a few inches to a foot or more above the ground surface. The clamp is then tightly secured to the top of the well casing by bolts 23 with the jaws 26 being approximately at the center of the casing. Thus, the clamp will not rotate upon the casing. The pull rod nut 45 is then adjusted so the clamp jaws 26 and head 30 will grip the pipe in the well. Thereafter, when the pipe string is to be gripped, the arm 31 is pulled against the pipe, the cam 42 is shifted to its seat 35 and the lobes are rotated to the locked position. The arm then holds the pipe tightly, with the splines 32 of the head gripping the pipe to prevent it from dropping into the well and the splines 29 of the notch gripping the pipe to prevent it from being turned. The operator is then free to apply wrenches to turn on or off couplings and other pipe lengths above the pipe section held by the clamp. Thereafter, the string is connected to the well hoist to be lowered or raised, so the clamp may grip another section of the string to continue the operation.

The modified embodiment illustrated at FIGS. 6-8 shows a more simple arrangement of basic components forming the improved clamp Ca. This clamp is formed upon a rectangular base plate 20a which is adapted to set upon and to be secured to the head of a well casing pipe. Lugs 22a carrying bolts 23a hold the clamp to the casing the same as heretofore described. Also, the plate 20a is formed with a throat 21a extending inwardly into the plate from one side thereof to embrace the well pipe which is to be held by the clamp.

The pipe gripping members at the throat 21a are formed by standard gripping jaws 26a such as the jaws of a heavy wrench or vise and these jaws are welded to the surface of the base plate in the V-notch arrangement as described. It is to be noted that the undersurface of the jaws include a mounting lug 60 at their center, and to facilitate securely welding the jaws in place, spacers 61 are placed at the undersides of each lug 6t? as illustrated at FIG. 7. The face of each jaw 26a, at the V-notch, is ridged with gripping splines 29a. These splines prevent a pipe held by the clamp from rotating.

The pipe gripping members also include a clamp head 30a which is carried upon a clamp arm 31a. The arm, in turn, is pivoted upon a pin 38a, preferably a hardened bolt, which upstands from the base plate 26a at one side of the throat. The pin is held in position by an abutment member 28a, which upstands from the base and includes a top cap 62 which overhangs the abutment member to hold the pin 38a in position, the pin extending through a hole in the cap 62, through a tubular bearing 370 at the end of the ann and thence into a hole 40a in the plate. The clamp head 30a at the center of the throat 21a is adapted to be pushed against a pipe placed in the V-notch of the jaws. Gripping splines 32a are provided at the face of the head 30 in a horizontal array normal to the jaw splines; accordingly, the splines 32a on the head 3th; will grip a pipe to prevent it from sliding downwardly when the clamp is holding the pipe tightly against the vertical splines 29. This head 30a is a standard vise-gripping unit and is conveniently welded onto the arm 31a as illustrated.

The end of the clamp arm 311a opposite the pivot connection is held by a pull rod 43a. One end of this rod extends through a loose hole 44a in the arm 31a and is threaded to be adjustably held by a nut 45a turned onto the rod. The other end of this rod is secured in an angle-shaped anchor abutment 35a by passing through a hole or slot 51a in this abutment to connect with a cammed lever 42a. The lever consists of a handle 48a with its end turned to form a pivot 500 which extends through an eye 49a of the pull rod 43a. Eccentric lobes 46a are welded to the lever pivot 50a to effect a pulling action on the rod 43a whenever the handle is rotated from a position away from and towards the jaws 26a as to the position shown in the drawing. A notch 63 is formed in the angle shaped abutment to hold this lever in place.

The manner in which this modified embodiment of a clamp is used, is essentially the same as that heretofore described in connection with the embodiment shown at FIGS. 1-5, excepting that a handle on the arm 31a is omitted and thus an operator cannot pull the arm against a pipe excepting with the pull of the lever 48a. This was found to be no great inconvenience.

I have now described my invention in considerable detail. However, it is obvious that others skilled in the art can build and devise alternate and equivalent constructions which are nevertheless within the spirit and scope of my invention. Hence, I desire that my protection be limited, not by the constructions illustrated and described, but only by the proper scope of the appended claims.

I claim:

1. A clamp for holding a string of pipe in a well which has casing at the top of the well, said clamp comprising:

a. base means adapted to rest upon and to overlie the top of the well casing and having a throat at one side to receive a pipe extending into the well;

b. splined jaw means forming an abutment at the crotch of the throat to engage said pipe;

c. a clamp arm including mounting means for pivotally mounting said arm on the base means to hold the pipe against the jaw means;

d. said mounting means including an abutment means upstanding from the base and a pin arranged to pivotally attach said am to said abutment means whereby said arm may move with respect to said jaw means;

e. head means attached to the clamp arm opposite the jaw means so as to engage the pipe, said head means having splines arranged transverse to the splines on the jaw means whereby the pipe can be held against slipping and rotation;

f. cam seat means mounted on said base means; and

g. cam loclr means connecting with said clamp arm and said cam seat means for holding the clamp arm means tightly against said pipe.

2. A clamp for holding a string of pipe in a well which has casing at the top of the well, said clamp comprising:

a. base means adapted to rest upon and overlie the top of the well casing and having a throat at one side to receive a pipe extending into the well;

c. a clamp arm pivotally mounted on said base means to hold the pipe against the jaw means;

d. head means attached to the clamp arm opposite the jaw means so as to engage the pipe, said head means having splines arranged transverse to the splines on the jaw means whereby the pipe can be held against slipping and rotation;

e. cam seat means mounted on said base means, said seat means comprising a flat member extending upwardly from said base means and arranged generally parallel to said clamp arm when in a clamping position;

f. said cam seat means having an aperture extending therethrough;

g. cam lock means connecting with said clamp arm and said cam seat means for holding the clamp arm means tightly against said pipe; and

h. the cam loclc means includes a bolt loosely connected at one end with the clamp arm means and arranged to extend through the aperture in said seat means, the opposite end of said bolt being pivotally attached to a cammed lever whereby as the lever is rotated against the seat means the clamp arm means is pulled toward the cam seat.

3. A clamp device as defined in claim 2, wherein:

the aperture in the cam seat means is an open slot extending inwardly from the outer edge of the cam seat means whereby the bolt may be slidably positioned within the aperture.

4. A clamp for holding a string of pipe in a well which has a casing at the top of the well, said clamp comprismg:

b. splined jaw means forming a V-shaped abutment at the crotch of the throat to engage said pipe;

c. said jaw means comprises splined jaw blocks upstanding from said base means and fixedly attached to said base means;

d. a clamp arm pivotally mounted on said base means to hold the pipe against the jaw means;

f. cam seat means mounted on said base means; and

g. cam lock means connecting with said clamp arm and said cam seat means for holding the clamp arm tightly against said pipe.

Claims

1. A clamp for holding a string of pipe in a well which has casing at the top of the well, said clamp comprising: a. base means adapted to rest upon and to overlie the top of the well casing and having a throat at one side to receive a pipe extending into the well; b. splined jaw means forming an abutment at the crotch of the throat to engage said pipe; c. a clamp arm including mounting means for pivotally mounting said arm on the base means to hold the pipe against the jaw means; d. said mounting means including an abutment means upstanding from the base and a pin arranged to pivotally attach said arm to said abutment means whereby said arm may move with respect to said jaw means; e. head means attached to the clamp arm opposite the jaw means so as to engage the pipe, said head means having splines arranged transverse to the splines on the jaw means whereby the pipe can be held against slipping and rotation; f. cam seat means mounted on said base means; and g. cam lock means connecting with said clamp arm and said cam seat means for holding the clamp arm means tightly against said pipe.

2. A clamp for holding a string of pipe in a well which has casing at the top of the well, said clamp comprising: a. base means adapted to rest upon and overlie the top of the well casing and having a throat at one side to receive a pipe extending into the well; b. splined jaw means forming an abutment at the crotch of the throat to engage said pipe; c. a clamp arm pivotally mounted on said base means to hold the pipe against the jaw means; d. head means attached to the clamp arm opposite the jaw means so as to engage the pipe, said head means having splines arranged transverse to the splines on the jaw means whereby the pipe can be held against slipping and rotation; e. cam seat means mounted on said base means, said seat means comprising a flat member extending upwardly from said base means and arranged generally parallel to said clamp arm when in a clamping position; f. said cam seat means having an aperture exteNding therethrough; g. cam lock means connecting with said clamp arm and said cam seat means for holding the clamp arm means tightly against said pipe; and h. the cam lock means includes a bolt loosely connected at one end with the clamp arm means and arranged to extend through the aperture in said seat means, the opposite end of said bolt being pivotally attached to a cammed lever whereby as the lever is rotated against the seat means the clamp arm means is pulled toward the cam seat.

3. A clamp device as defined in claim 2, wherein: the aperture in the cam seat means is an open slot extending inwardly from the outer edge of the cam seat means whereby the bolt may be slidably positioned within the aperture.

4. A clamp for holding a string of pipe in a well which has a casing at the top of the well, said clamp comprising: a. base means adapted to rest upon and to overlie the top of the well casing and having a throat at one side to receive a pipe extending into the well; b. splined jaw means forming a V-shaped abutment at the crotch of the throat to engage said pipe; c. said jaw means comprises splined jaw blocks upstanding from said base means and fixedly attached to said base means; d. a clamp arm pivotally mounted on said base means to hold the pipe against the jaw means; e. head means attached to the clamp arm opposite the jaw means so as to engage the pipe, said head means having splines arranged transverse to the splines on the jaw means whereby the pipe can be held against slipping and rotation; f. cam seat means mounted on said base means; and g. cam lock means connecting with said clamp arm and said cam seat means for holding the clamp arm tightly against said pipe.