GB2139129A - Hydraulic wrench - Google Patents

Abstract

There is provided a hydraulic wrench for loosening and tightening threaded joints connecting two members. The wrench comprises a body, a first (24), a second (46) and a third (70) hydraulic cylinder, a first (30), a second (66) jaw means, and a first (52) and a second (74) clamping chain wherein the second and the third hydraulic cylinders (46, 70) and their respectively first and second clamping chains (52, 74) serve to forcefully clamp the first and second members (A and B) against the respectively first and second jaw means (30, 66), and the first hydraulic cylinder (24) serves to apply a torque to the first member (A) via the first jaw means (30). The wrench may be used for "breaking up" drilling hammers, drilling bits, drill pipes etc. <IMAGE>

Description

SPECIFICATION Hydraulic wrench The present invention relates to a hydraulic wrench for "breaking up" drilling hammers, drilling bits, drill pipe, and the like.

"Breaking up", i.e., unscrewing, a drilling hammer is liable to be a laborious and frustrating task requiring a great physical effort on part of the operators and, sometimes, such time-consuming improvisations as the temporary welding-on of lugs and projections to provide grip for associated crow bars and wrenches.

The present invention seeks to overcome these difficulties and to provide a wrench that, at the push of a lever, will produce a hydraulic clamping force as well as a torque large enough to break up the most stubborn threaded joint.

According to the present invention, there is provided a hydraulic wrench for the loosening and tightening of threaded joints connecting two members, comprising a body; a first hydraulic cylinder one end of which is articulated to one end portion of said body; first jaw means slidably suported by said body, to one end portion of which first jaw means is articulated the other end of said first hydraulic cylinder, and the other end portion of which jaw means is adapted to be forcefully applied against the first of said members; a second hydraulic cylinder, one end of which is articulated to said first jaw means; a first articulated clamping chain comprising a plurality of clamping links, one end of which first chain is articulated to said forest jaw means and the second end of which chain is articulatable to the second end of said second hydraulic cylinder; second jaw means attached to one end portion thereof to a second end portion of said body, and the second end portion of which second jaw means is adapted to to be forcefully applied against the second of said members; a third hydraulic cylinder, one end of which is articulated to said second jaw means; a second articulated clamping chain comprising a plurality of clamping links, one end of which second chain is articulated to said second jaw means and the second end of which chain is articulatable to the second end of said third hydraulic cylinder, said first, second and third hydraulic cylinders being connectable to a source of hydraulic pressure, wherein said second and said third hydraulic cylinders and their respectively first and second clamping chains serve to forcefully clamp said first and second members against said respectively first and second jaw means, and said first hydraulic cylinder serves to a apply a torque to said first member via said first jaw means.

The invention will now be described further, by way of example with reference to the accompanying drawings. In this regard, no attempt is made to show structural details of the invention in more detail than is necessary for a fundamental understanding of the invention, the description taken with the drawings making apparent to those skilled in the art how the several forms of the invention may be embodied in practice.

In the drawings: Figure 1 is a side view of a preferred embodiment of the hydraulic wrench according to the invention; Figure 2 is a top view of the device; Figure 3 shows a perspective view of the body of the hydraulic wrench of Figure 1; Figure 4 is a perspective view of the torquing jaw, and Figure 5 represents a kinematic diagram of the hydraulic wrench.

Referring now to the drawings, there is seen in Figure 1 & Figure 2 a body 2 mounted on a chassis 4 provided with a pair of wheels 6. The body 2, shown in greater detaii in Figure 3, can be designed as a casting or, as shown in the Figure, can be fabricated from steel plate. The details drawn in dash-dotted lines pertain to a variant of the present embodiment and will be explained further below. The body 2 is seen to comprise a top plate 8 and a bottom plate 10, the left end portions of which two plates, in conjunction with a rear plate 13 and a side plate 14 constitute a box-like structure. Another, upper, box-like structure 15 is seen on the right end portion of the top plate 8. Bores 16, 18, and 18' are provided for pins 20 and 22, respectively (Figures 1 and 2).Pin 20 is used to attach the pivotable end of a first hydraulic cylinder 24, the piston rod 26 of which is articulated by means of a pin 18 to a first jaw 30, through which, as will be shown further below, a torque will be applied to the member A, say, a stem, to be unscrewed from, or tightened to, a member B, say a drill bit (see Figures 1 and 5).

This jaw 30 is shown to better advantage in Figure 4, where it is seen to consist of an upper plate 32 and a lower plate 34 held together by spacers 36 visible in Figure 1. Also seen are three pins 28,38 and 40, the latter two pins being mounted in lateral projections of the upper and lower plates 32 and 34. Also seen are two gripping pads 42 with serrated faces which, as will be shown, are pressed gains the members A and B to provide grip. In another configuration of the gripping faces, they may consist of a plurality of small, sharply pointed pyramids. The pads 42 are fixedly attached to the plates 32, 34 and are advantageously made of hardened steel or hard metal such as sintered carbides.

In assembly, this jaw 30, as already stated, is attached by means of a pin 28 to the piston rod 26 of the first hydraulic cylinder 24 and rests on a rail 44 attached to the top plate 8 of the body 2.

Articulated to the pin 38 is the pivotable end of a second hydraulic cylinder 46, to the end of the piston rod 48 of which is removably hinged one of the terminal links 50 of a first articulated clamping chain 52 consisting of a number of clamping links 54 hinged to one another by means of hinge pins 56 secured with the aid of retaining rings as such known and not shown in the drawings. The terminal link 50 is provided with a hinge pin 58 having a handle 60, the shape of which is better understood from Figure 1, and which faciltates removal of the terminal hinge pin 58. The other terminal link, 62, is attached to the first jaw 30 by means of the previously mentioned pin 40. Each link 54, as well as the terminal links 50 and 62, is provided with gripping pad 64 similar in configuration to the pads 42 of the first, or torquing, jaw 30.

In the lower box-like structure of the body 2 (Figure 3) there is located a second, or steady, jaw 66, shown mostly in dotted lines and anchored to the body 2 by means of the pin 20. The latter has two alternative positions, the first comprising bores 18 (Figure 3) for cases when member A and member B (Figures 1 and 5) are of substantially equal diameter, and the second comprising bores 18', when the diameter of member B is substantially larger than that of member A. The shape and design of the second jaw 66 is similar to that of the first jaw 30, except that it is shorter by the distance between the bores 18 and 18' and that, compared to the first jaw 30, it is mounted upside down, i.e., plate 34 on top and plate 32 below. When mounted, the second jaw 66 is able to slightly swivel about the pin 22.

Articulated to the pin 68 (the analogue of the pin 38 of the first jaw 30) is the pivotable end of a third hydraulic cylinder 70, to the end of the piston rod 72 of which is removably hinged one of the terminal links, 50, of a second articulated clamping chain 74 consisting of a number of clamping links 54 hinged to one another by means of hinge pins 56. Also provided is the terminal hinge pin 58 with handle 60 for the terminal link 50. The other terminal link, 62, is attached to the second jaw 66 by means of the pin 76. The links ofthe second clamping chain 74 are equally provided with gripping pads 64. With both clamping chains, links can be removed or added, to suit the diameters of A and Bto be handled bythe hydraulic wrench.The present embodiment is suitable for a range of diameters from 5 to 30 inches (12.5to 75 cms.).

The hydraulic circuit of the wrench according to the invention is very simple. A hydraulic pump 78 mounted beneath an oil reservoir 80 is driven by a petrol engine 82, pressure being conveyed via hydraulic hoses 84 (not fully shown for sake of clarity) to the respective cylinders according to the position of the control levers C1 (for first cylinder 24), C2 (for second cylinder 46) and C3 (forthird cylinder 70). The entire engine/pump unit is mounted in a tubular extension 86 of the chassis 4, which extension also comprises a handle 88 by which the hydraulic wrench can be moved about and maneuvered into position. Also provided, although not shown in the drawings, is a lifting lug for hoisting the wrench, e.g., for transport.

While provision of a petrol engine makes the hydraulic wrench fully self-contained and independent of external power sources, it can obviously be provided with an electric motor instead, for use at sites where electric power is readily available. The cylinders 24,48 and 70 could also be connected to an outside source of hydraulic pressure, if such be available.

The operation of the hydraulic wrench according to the invention is best understood from the kinematic scheme shown in Figure 5, where A represents the member to be unscrewed or tightened, and B the stationary member, e.g., the working bit.

In the preparatory stage (not shown) the wrench, on its wheeled chassis, has been maneuvered into a position in which the lower jaw 66 more or less touches the member B with its gripping pads 42, and the upper jaw 30 does so with the member A. The clamping chains 52 and 74, previously unhinged by removal of the hinge pins 58, are then loosely slung around the members A and B, and the pins 58 replaced. Now the control levers C2 (cylinder 46) and C3 (cylinder 70) are moved in a direction that makes the piston rods 48 and 72 withdraw, which will tighten the clamping chains 52 and 74 around the members A and B, respectively, as well as apply the jaws 30 and 66 with their gripping pads 42 against the members A and B. Equally applied against their respective members are of course also the gripping pads 64 of the chain links 54.

Now the first cylinder 24 is actuated by moving the control lever C1 in a direction determined by whether the wrench is required to unscrew the member A, or thighten it. Assuming the threaded joint to have right-handed threads, unscrewing will be effected by pushing out the piston rod 26, which will apply to the jaw 30 a torque causing it turn in a counterclockwise sense about the axis Z of the members A and B. From the kinematic representation of Figure 5, it is clear that the lever arm (pivot 28 to axis Z) being relatively short and the hydraulic cylinder 24 being privoted at both ends, the force transmitted to the members A and B is almost pure torque, the bending moment being negligible. As one full stroke of the hydraulic cylinder 25 will rarely suffice to completely loosen the joint, several "runs" might be required.After each run, the starting position (piston rod fully "in" for unscrewing, fully "out" for tightening) has to be restored. This is done by reversing pressure in cylinder 46, which will cause the piston rod 48 to move out, thereby eliminating the pull on the clamping chain 52 and releasing its grip on the member A. (The lower clamping chain 74 remains tightended).

Now oil presure in cylinder 24 is reversed which, in the present case, will cause the piston rod 26 to withdraw, pulling along also the upper jaw 30, but, because of the loosened chain 52, not affecting the member A.

At this point the chain 52 is re-tightened by pressure reversal in cylinder 46. The second unscrewing "run" can now be started by pressure reversal in cylinder 24. These runs are repeated as often as necessary.

For tightening one proceeds analogously, except that the torque has to be applied in the clockwise sense.

For better understanding of the operation of the wrench, it should be remembered that the upperjaw 30 is in no way directly connected to the body 2, being merely freely and slidably supported by the rail 44 (Figures 1 and 2).

While the above-discussed embodiment is designed for use with vertically extending drilling components, variant of this embodiment also permits its application to horizontally extending components such as large pipes, etc.

In this variant, the body 2 (Figure 3) is not directly mounted on the chassis 4, but is attached to a vertical extension 90 thereof, via a sturdy mounting bracket 92 affixed to the top plate 8. A pivot (not show) passing through the bore 94 permits the body 2 and all associated components to tilt from the horizontal position shown to a vertical position.

Yet another variant extends the use of the hydraulic wrench according to the invention also to cases in which the lower member B is not only substantially larger in diameter than the upper member A, but has an extended tapered transition section along which its larger diameter is gradually reduced to the diameter of member A. In such cases the distance between the two clamping chains 52 and 74 is liable to be too small for the chain 74 to grip its member B along the cylindrical portion thereof. In that case the distance between the chain 52 and chain 74 must be increased. In the present variant, this is achieved by providing another box-like struc ture, 15', on top of the original structure 15, and transferring the hydraulic cylinder 24 and its pivot pin 20 to this elevated position. An attachment (not shown) affixable to the rail 44 will increase the height of the latter up to the new position of the jaw 30.

While the above-discussed embodiment and its variants were all wheel-mounted, i.e., mobile, the hydraulic wrench can also be adapted to become a permanent fixture, to be mounted on a drill jug.

While particular embodiments of the invention have been described, it will be evident to those skilled in the art that the present invention may be embodied in other specific forms. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims ratherthan by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are, therefore, intended to be embraced therein.

Claims (7)

1. A hydraulic wrench for the loosening and tightening of threaded joints connecting two members, comprising a body; a first hydraulic cylinder one end of which is articulated to one end portion of said body; first jaw means slidably supported by said body, to one end portion of which first jaw means is articulated the other end of said first hydraulic cylinder, and the other end portion of which first jaw means is adapted to be forcefully applied against the first of said members; a second hydraulic cylinder, one end of which is articulated to said first jaw means; a first articulated clamping chain comprising a plurality of clamping links, one end of which first chain is articulated to said first jaw means and the second end of which chain is articulatable to the second end of said hydraulic cylinder; second jaw means attached at one end portion thereof to a second end portion of said body, and the second end portion of which second jaw means is adapted to be forcefully applied against the second of said members; a third hydraulic cylinder, one end of which is articulated to said second jaw means; a second articulated clamping chain comprising a plurality of clamping links, one of which second chain is articulated to said second jaw means and the second end of which chain is articulatable to the second end of said third hydraulic cylinder, said first, second and third hydraulic cylinders being connectable to a source of hydraulic pressure, wherein said second and third hydraulic cylinders and their respectively first and second clamping chains serve to forcefully clamp said first and second members against said respectively first and second jaw means, and said first hydraulic cylinder serves to apply a torque to said first member via said first jaw means.

2. The hydraulic wrench as claimed in Claim 2, further comprising pump and control means to operate said hydraulic cylinders and a prime mover to drive said pump.

3. The hydraulic wrench as claimed in Claim 2, wherein said prime mover is a petrol engine.

4. The hydraulic wrench as claimed in any preceding claim, further comprising a chassis with at least one pair of wheels on which to mount said hydraulic wrench, and a handle for moving said wheel-mounted hydraulic wrench.

5. The hydraulic wrench as claimed in any preceding claim, further comprising a swiveling mounting bracket for said body, whereby said body can be swiveled from a first positiOn, in which said body is substantially horizontal, to a second position, in which said body is substantially vertical.

6. The hydraulic wrench as claimed in any preceding claim, wherein elevating means are provided to increase the distance, along said members, between said first and second clamping chain.

7. A hydraulic wrench substantially as herein described with reference to and as illustrated in the accompanying drawings.