US3389624A

US3389624A - Sliding jaw pipe wrench having automatically acting pin and hole adjustment means

Info

Publication number: US3389624A
Application number: US668988A
Authority: US
Inventors: Jr Carroll Everrett Pooler
Original assignee: Carroll Everrett Pooler Jr.
Current assignee: CARROLL EVERRETT POOLER JR
Priority date: 1967-09-01
Filing date: 1967-09-01
Publication date: 1968-06-25
Anticipated expiration: 1985-06-25

Description

June 25, 1968 c. E. POOLER, JR 3,389,624

SLIDING JAW PIPE WRENCH HAVING AUTOMATICALLY ACTING PIN AND HOLE ADJUSTMENT MEANS Filed Sept. 1, 1967 3 Sheets-Sheet 1 I I I I I I I I q 7 I I Z I d .4 I I a i.

0' Ll. & I r' I Q m INVENTOR CdrroIl E. PooIer,Jr.

ATTORNES c. E. POOLER, JR 3,389,624 SLIDING JAW PIPE WRENCH HAVING AUTOMATICALLY ACTING June 25, 1968 PIN AND HOLE ADJUSTMENT MEANS l, 1967 5 Sheets-Sheet 5 Filed Sept.

INVENTOR Cu roll E. Pooler,Jr.

ATTORNEY June 25, 1968 E. POOLER, JR 3,389,624 BENCH HAVING AUTOMATICALLY ACTING ND HOLE ADJUSTMENT MEANS SLIDING JAW PIPE PIN A 3 Sheets-Sheet f5 Filed Sept.

n. M U L INVENTOR Carroll E. Poo\er,Jr.

ATTORNEEF United States Patent Oflice 3,389,624 Patented June 25, 1958 SLIDlNG JAW PIPE WRENCH HAVING AUTO- MATICALLY ACTING PIN AND HOLE AD- JUSTMENT MEANS Carroll Everrett Pooler, Jr., Rte. 1, Box 133-F,

Lafayette, La. 70501 Filed Sept. 1, 1967, Ser. No. 668,988 13 Claims. (Cl. 81-429) ABSTRACT OF THE DISCLOSURE A pipe wrench comprising a handle having a web and having an upper flange and a lower flange, and having a lateral extension at one end; a fixed jaw on said extension; a reciprocable slide block underlying and embracing the lower flange; a movable jaw eccentrically pivotally mounted on the slide block opposite the fixed jaw; rods extending rearwardly of and anchored in the slide block at each side of the web; guides for said rods mounted on said lower flange; coiled springs on said rods interposed between the guides and slide block for forcibly projecting the movable jaw towards the fixed jaw to clamp the work therebetween; a pair of handle blocks independently slidably mounted on the top of the slide block at each side of the web, and having recesses in their inner faces receiving and interlocking with the top flange and web of the beam to prevent removal therefrom, the handle blocks having portions forming handles for retracting the slide block; means for normally locking each handle block to the slide block; the lower flange having a series of holes therethrough; an inclined cam slot in each block, a cam slidable in each slot; an offset pin carried by each cam slidable in a bore therefor in the slide block and adapted to enter one of said holes in the flange when same register; means for normally urging the handle blocks forwardly of the slide block when the locking means is released; whereby when the handle blocks are retracted the springs will be compressed and the pins will be raised out of the holes in the flange, and the locking means of the handle blocks will be engaged, and when the handle blocks are released the springs will force the slide block carrying the movable jaw into con tact with the work, jolting the locking means into inoperative position, permitting the urging means to shift the handle blocks forwardly on the slide block thereby lowering the pins into the aligned hole in the lower flange.

This invention relates to pipe wrenches or the like, and the principal object of the invention is to provide a self adjusting positive-acting wrench which may be used for rotating any cylindrical shape, same being designed to handle pipe ranging in size from approximate A to 6", and thus can be used with a range of the pipe sizes, thus allowing the wrench to be applicable for competition with standard pipe wrenches as well as for competition with pipe tongs such as ordinarily used in the oil industry.

More specifically, the primary object of the invention is to provide a pipe wrench comprising a handle having a web and having an upper flange and a lower flange, and having a lateral extension at one end; a fixed jaw on said extension; a reciprocable slide block underlying and embracing the lower flange; a movable jaw eccentrically pivotally mounted on the slide block opposite the fixed jaw; rods extending rearwardly of and anchored in the slide block at each side of the web; guides for said rods mounted on said lower flange; coiled springs on said rods interposed between the guides and slide block for forcibly projecting the movable jaw towards the fixed jaw to clamp the work therebetween; a pair of handle blocks independently slidably mounted on the top of the slide block at each side of the web, and having recesses in their inner faces receiving and interlocking with the top flange and web of the beam to prevent removal therefrom, the handle blocks having portions forming handles for retracting the slide block; means for normally locking each handle block to the slide block; the lower flange having a series of holes therethrough; an inclined cam slot in each block; a cam slidable in each slot; an offset pin carried by each cam slidable in a bore therefor in the slide block and adapted to enter one of said holes in the flange when same register; means for normally urging the handle blocks forwardly of the slide block when the locking means is released; whereby when the handle blocks are retracted the springs will be compressed and the pins will be raised out of the holes in the flange, and the locking means of the handle blocks will be engaged, and when the handle blocks are released the springs will force the slide block carrying the movable jaw into contact with the work, jolting the locking means into disengaged position, permitting the urging means to shift the handle blocks forwardly on the slide block thereby lowering the pins onto the lower flange ahead of the holes in the lower flange, and subsequently lowering the pins into the holes when aligned therewith.

Another object of the invention is to provide a wrench of the above type in which the lower end of the movable jaw base is bifurcated and carries a pivot pin housed in said bifurcations offset forwardly of the axis of the post, and said movable jaw is rockably mounted on said pin and has a serrated convex front face whose axis of curva ture is olfset from the pin; and said movable jaw has a heel at its rear end normally separated from the lower rear end of the movable jaw base, thereby permitting the jaw to rock when engaged with an article clamped between the fixed and movable jaws.

A further object of the invention is to provide a wrench of the above type in which said heel of the movable jaw engages the lower rear end of the movable jaw base only when the jaws engage said article and a clockwise rotative force is applied to the wrench handle.

Other minor objects of the invention will be hereinafter set forth.

I will explain the invention with reference to the accompanying drawings, which illustrate one practical embodiment thereof, to enable others familiar with the art to adopt and use the same; and will summarize in the claims the novel features of construction, and novel oombinations of parts, for which protection is desired.

In said drawings:

FIG. 1 is a side elevation partly in section of my novel wrench showing the movable jaw retracted the maximum amount prior to release for impact with the pipe which is in contact with the fixed jaw, and showing the parts of the assembly in normal disengagement.

FIG. 2 is a reduced side elevation of the wrench shown in FIG. 3 showing parts of the movable jaw in the position assumed after impact of the movable jaw with the pipe.

FIG. 3 is an enlarged view of FIG. 2 showing the parts of the movable jaw carrier in the positions assumed after impact and after locking of the action assembly.

PEG. 4 is a view similar to FIG. 3 but showing the parts of the movable jaw assembly after impact and prior to locking of the assembly.

FIG. 5 is a transverse sectional view on the line 55, FIG. 3.

FIG. 6 is a partial bottom plan view of the wrench,

partly in section, looking at the underside of the movable jaw.

FIG. 7 is a top plan view of the wrench, partly in section, showing the springs for causing impact of the pipe by the movable jaw.

FIG. 8 is a section through the I-beam with the handle blocks removed, showing the top of the slide for the removable jaw.

As shown in the drawings, my novel wrench preferably comprises a handle 1 of I-beam cross-section having an upper flange la and a lower flange 1b, the base raving at its forward end a lateral extension Etc projecting normal to the axis of the handle and forming a base for the fixed jaw 2, which has a shank 2x engaging bore lid adjacent the end of the extension 10, the shank being fixed in the bore by means of a set screw 3. Any other desired means for locking the fixed jaw 2 to the extension 10 however may be used.

The movable jaw holder comprises a slide block 4 which underlies the lower flange 1b of the I-beam and has raised sides 4a which embrace the lower flange 1b, the upper ends of the sides 4a being inturned as at 412 (FIG. 5) to overlie the top of the lower I-beam flange 1]), whereby the slide 4 may be reciprocated on the flange lb while carried thereby.

At the rear end of slide 4 at each side thereof is a lug .0 below which is a seat id (FIG. 1) for a rod 5 which is anchored in the seat dd and extends rearwardly and parallel with the web, the inner end of the rod 5 passing through a guide 6 secured in any desired manner to the lower flange 1b, as shown in FIGS. 1 and 7. A strong coil spring 7 is carried by each rod 5 interposed between the guide 6 and the slide 4, each side of the web of the I-beam, the spring 7 being adapted under certain conditions to forcibly project the slide 4 forwardly to bring the movable jaw 9 into contact with the pipe or work P. When, however, the slide 4 is manually retracted towards the guide 6 each spring 7 will be compressed to energize the spring 7. The placing of the guide 6 and the characteristics of the spring serve to limit the rearward or retractable movement of the slide 4.

The bottom of the slide 4 projects below the flange lb as shown in FIGS. 1 and 5, and is bifurcated as at 4e, 4 FIG. 5, and is provided with a transverse bore 4g extending through the bifurcations adapted to receive a pivot pin 8 which passes through the bore 4g and through a bore in the upper end of the movable jaw whereby the upper jaw 9 may be readily rocked on the pin 3, the movable jaw 9 being disposed in axial alignment with the fixed jaw 2.

Independently slidably mounted upon the top of the slide 4 are a pair of blocks 10 (FIGS. 1 and 5) of complementary shape, the combined width of the blocks being the same as that of the slide 4, and blocks 10 having recesses in their inner sides receiving and embracing the top flange 1a of the I-beam 1. As shown in FIG. 5, the recess in the blocks have a piston 10a in its inner side adapted to conform with the upper surface of the top flange 1a of the I-beam, and also a portion conforming with the side face of the upper flange 1a and also a portion conforming with and underlying the upper surface of the flange 1a, which latter portion is provided with a raised rib 10b engaging a longitudinal slot 4k formed in the under surface of the flange 1a at each side of the web. Said recess also has a portion engaging the adjacent face of the web of the I-beam and terminating at the top of the flange 4b of the slide 4 whereby when the blocks 10 are positioned on opposite sides of the I-beam as shown in FIG. 5, they will be interlocked with the I-beam to prevent removal therefrom except at as a unit, each block being individually slidable upon the slide 4. Normally however, the two blocks 10 would be movable together as a unit.

Means are provided for locking each block 10 to the slide 4. As shown in FIG. 1, each block 10 has a forward lug or projection 10c having a circular bore which is open at the top and underlies the upper flange 1a of the I-beam 1, the lower end of the bore being reduced and adapted to receive a reciprocable pin 12 normally extending through the reduced bore, the head of the pin being normally depressed by a spring 12a so as to urge the lower end of the pin 12 into a hoe 411, FIG. 8, in the top of the slide 4, whereby when the pin 12 is so engaged the corresponding block 10 is normally locked to the slide 4.

Through the bottom flange 1b are a series of holes lj, FIGS. 1 and 6, adapted to be engaged by a pin carried by the slide 4 to lock the slide against movement by the springs 7, the holes lj being arranged for different ranges of pipes P.

As shown in FIGS. 1 and 5, an inclined cam slot 13 is provided adjacent the lower end of each block 10, one

such slot being provided in each block at opposite sides of the web of the I-beam and adapted to receive a cam 14 which is slidable in said slot from the position shown in FIG. 1 to the position shown in FIGS. 3 and 4.

On the inner end of each cam 14 is a cylindrical pin 15 which may be projected into registering bores in the blocks 1 and slide 4, as shown in FIG. 3, as the cams 14 are moved along the inclined cam slots 13. Thus, as shown in FIG. 1, the cam 14 is at the upper end of the slot 13 and the pin 15 is therefore retracted upwardly above the top of the lower flange 1b of the I-beam, while in FIG. 3 the cam 14 is at the lower end of the cam slot 13 and the pin 15 is in its lowermost position extending through the registering bores in the blocks 10 and slide 4 and also extending into one of the holes 1 in the bottom flange 1b of the I-beam, thereby locking the slide 4 against further movement on the I-beam. In FIG. 4 the pins 15 are shown in inoperative or disengaged position.

Means are provided for normally shifting the blocks 10 forwardly with respect to the slide 4, said means as shown comprising a rod 17 for each block 10 extending through the lug 4c of the slide 4 with the forward ends secured to the rear face of the block 10, a spring 18 around the rod being interposed between the lug 4c and the block It supplying continuous yielding pressure to urge the block 10 forward of the slide 4 until the rear end of the cam slot 13 is engaged by the related cam block 14, as shown in FIG. 3.

The fixed jaw 2 has an arcuate front face 2a as shown, conforming in general to the average diameter of the pipe P, and said face is provided with serrated teeth 2b, the central portion of the recess 2a being cut away as at 2c, as shown. Preferably the teeth 2b are such that their axes, i.e., a line drawn perpendicularly to their arcuate positions on arcuate face 20, would intersect at the center of the pipe P held by the wrench.

The movable jaw 9, however, is formed with a front arcuate surface 9a provided with teeth 91) which are so formed that as the jaw is pivoted on the pivot pin 8 when in contact with the pipe P in the axes of each of the teeth 9b in contact with the pipe will pass through or intersect the center of the pipe P which is being held in the wrench, so that the force exerted by jaw 9, as well as by jaw 2, is directed towards and would intersect the center of the pipe P which is held by the wrench. By such arrangement of teeth 9b on the jaw 9 and teeth 212 on jaw 2, said teeth are focused only on the diameter of the pipe, the axes of the teeth of both the fixed jaw and movable jaw being directed towards the center of the pipe being worked upon, such action insuring that the teeth of both jaws will cut without slipping into the surface of the pipe, without any tendency to rotate the pipe in the jaws, unless actuated by manual clockwise or counterclockwise movement of the wrench.

As shown in FIG. 3, the top of the movable jaw 9 in rear of the pivot 8 is provided with a shoulder 9c adapted to engage a corresponding shoulder 4x on the bottom face of the slide 4, as shown in FIG. 4, in which position the uppermost teeth 9b of the movable jaw 9 would allow ratcheting, i.e., manual clockwise and counterclockwise joggling of the wrench handle. It is desirable, however,

that the central teeth 9b be brought to bear against the pipe, as shown in FIG. 3, and for this purpose I provide an inclined bore 4y in the slide 4 opening against the underside of the lower flange 1a of the I-bearn 1, said bore 4y being reduced at its lower end to receive a pin 20 which extends through the lower end of the bore 4y and engages the movable jaw heel 9c, a spring 4z in bore 43 acting on pin 26, normally urging the movable jaw 9 to pivot on the pin 8 in the manner shown in FIGS. 1 and 3. Such pivoting will bring the central teeth 9b more or less into engagement with the pipe P thereby insuring a force couple. If a clockwise movement is then exerted upon the wrench handle by the operator, by raising same upwardly, a clockwise motion is imparted to the jaw 9 which will allow the wrench to be ratcheted about the work. If a counterclockwise motion is exerted upon the handle by the operator, the resulting action imparts a counterclockwise motion to the jaw 9, further engaging the serrated teeth 9b into the pipe P across the diameter thereof.

Means are provided for limiting the pivoting of the movable jaw 9 towards the pipe P in a counterclockwise direction when the wrench is disengaged, said means comprising a resilient pawl 21 adapted to engage a surface of the jaw 9 adjacent the upper limit of the teeth 9b, as shown in FIG. 1. The pawl 9 will bend upwardly as counterclockwise rotation of jaw 9 causes a shoulder above the teeth 9b to apply tension. Maximum counterclockwise rotation is regulated when said shoulder contacts a stop adjacent to pawl 21 similar to the heel 9c-4x relationship.

In operation, in using the wrench the operator will pull rearwardly on the handles 10, thus compressing the springs 7. During such rearward movement the cam blocks 14 assume the position in their slots 13 shown in FIG. 1 wherein the cam blocks are at the forward ends of the cam slots 13 with the cam blocks 14 abutting against the lugs 100. Since the cam blocks 14 are at the forward end of the cam slots 13, in such position the pins 15 will be raised out of engagement with the holes 1 in the lower flange 1a of the I-beam, as shown in FIG. 1, and in such position the springs 18 will be compressed as shown in FIG. 1, while the pins 12, FIG. 1, will be seated in the holes 4h, FIG. 8, in the slide 4. Said rearward motion, having locked the blocks to the slide 4 by means of the pins 12, will have compressed the springs 7 to the maximum amount, thus limiting the rearward motion of theslide 4, the operator manually holding the associated parts in said cocked position until ready to manually release the movable jaw assembly for contact with the pipe P.

When the blocks 10 are manually released by the operator the springs 7 will shift with considerable force the slide 4 forwardly on the I-beam until it initially contacts the pipe P positioned against the fixed jaw 2, the parts then assuming the positions shown in FIG. 4, the spring 4z acting as a decelerator of the slide 4 after impact of the movable jaw 9 with the pipe P. Said spring 42. also serves to keep a constant pressure after impact of the movable jaw 9 on the pipe P. Moreover, spring 4z having been compressed as indicated in FIG. 4, will by applying pressure against shoulder 4x move slide 4 rearwardly allowing pin under pressure of spring 18 to align with hole 1 with or without the aid of the operators hand on handles 10.

The primary function of the pin 12 depressed by the spring 12a and which seats in a hole 4h in slide 4, when the pin 15 is raised by cam block 14 to its maximum height, is to prevent the spring 18 from urging the handle 10 forwardly relative to the slide 4 and thereby pushing the pin 15 downwardly into contact with the upper surface of the lower flange 1b of the I-beam while the assembly of the movable jaw 9 is being thrust forwardly by the main spring 7, thus preventing the pin 15 in its movement from entering any of the holes lj in the I-beam until impact of the jaw 9 with the pipe P causes pin 12 to be jolted and raised from hole 4h, whereupon the potential force of the compressed spring 18 will slide the handle 10 forwardly on slide 4 camming the pin 15 downwardly upon the upper face of the flange 1b with positive pressure, so that same may, if aligned with the hole, engage the proper hole 1 for the diameter of the pipe P being worked upon. If the pin 15 is not exactly aligned with the proper hole 1], the spring 4z under compression will move slide 4 rearwardly, or a slight counterclockwise pressure on the wrench handle exerted by the operator will result in a rearward force exerted upon the slide 4 and will align the proper hole 1j and the pin 15. The positive pressure above indicated against pin 15 will now seat pin 15 into hole 1] and the parts are locked for Wrench operation, as indicated in FIG. 3.

I do not limit my invention to the exact form shown in the drawings, for obviously changes may be made therein within the scope of the claims.

I claim:

1. A pipe wrench comprising a handle having a web and having an upper flange and a lower flange, and having a lateral extension at one end; a fixed jaw on said extension; a reciprocable slide block underlying and embracing the lower fiange; a movable jaw eccentrically pivotally mounted on the slide block opposite the fixed jaw; rods extending rearwardly of and anchored in the slide lock at each side of the web; guides for said rods mounted on said lower flange; coiled springs on said rods interposed between the guides and slide block for forcible projecting the movable jaw towards the fixed jaw to clamp the work therebetween; a pair of handle blocks independently slidably mounted on the top of the slide block at each side of the web, and having recesses in their inner faces receiving and interlocking with the top flange and web of the beam to prevent removal therefrom, the handle blocks having portions forming handles for retracting the slide block; means for normally locking each handle block to the slide block; the lower flange having a series of holes therethrough; an inclined cam slot in each block; a cam slidable in each slot; an oifset pin carried by each cam slidable in a bore therefor in the slide block and adapted to enter one of said holes in the flange when same register; means for normally urging the handle blocks forwardly of the slide block when the locking means is released; whereby when the handle blocks are retracted the springs will be compressed and the pins will be raised out of the holes in the flange, and the looking means of the handle blocks will be engaged, and when the handle blocks are released the springs will force the slide block carrying the movable jaw into contact with the work, jolting the locking means into inoperative position, permitting the urging means to shift the handle blocks forwardly on the slide block thereby lowering the pins into the aligned hole in the lower flange.

2. In a wrench as set forth in claim 1,. the lower end of the movable jaw being bifurcated; a pivot pin housed in said bifuractions; said movable jaw being rockably mounted on said pin and having a toothed convex front face whose axis is offset from the pin; and said movable jaw having a heel at its rear end normally separated from the lower rear end of the slide block thereby permitting the jaw to rock when engaged with an article clamped between the fixed jaw and movable jaw.

3. in a wrench as set forth in claim 2, said heel of the movable jaw engaging the lower rear end of the slide block only when the jaws engage the work and a clockwise rotative force is applied to the handle.

4. In a wrench as set forth in claim 2, the teeth being such that as the jaw is pivoted when in contact with the work, the axes of the teeth will pass through the approximate center of the work.

5. In a wrench as set forth in claim 2, said slide block having an inclined bore in its lower end opening against the underside of the lower fiange; a pin in said bore engaging the heel of the movable jaw to urge the movable jaw to pivot; and a spring in said inclined bore acting upon said pin; said pin serving as a decelerator for the slide after impact of the movable jaw with the work, and serving to maintain constant pressure after impact of the movable jaw on the work.

6. In a wrench as set forth in claim 2, means for yieldably resisting the pivoting movement of movable jaw towards the work comprising a pawl adapted to engage a surface of the movable jaw adjacent the upper limit of the teeth thereon.

7. In a wrench as set forth in claim It, said fixed jaw having an arcuate front face provided with teeth so disposed that the axes of said teeth intersect the approximate center of the work held by the wrench.

8. In a Wrench 'as set forth in claim 1, said normally locking means comprising a lug on each handle block having a bore open at the top and underlying the upper flange, the lower end of the bore being reduced in diameter; a reciprocable pin the bore extending through said reduced end; and spring in the bore urging the pin downwardly to engage a hole in the top of the slide, said pin being releasable by the jolt of impact of the movable jaw against the work.

9. In a wrench as set forth in claim 1, said normally urging means comprising a rod on the rear end of each handle block extending rearwardly through a lug on the slide block and having its forward end secured to the rear face of the related handle block; a coiled spring around the rod interposed between the lug and block for yieldably urging the related block forwardly of the slide block until the rear end of the related cam slot is engaged by the related cam block, in which position the related pin will enter the hole in the lower flange.

10. A pipe wrench comprising a handle of I-beam cross-section having a web and having an upper flange and a lower flange; said handle having a lateral extension at one end; a fixed jaw mounted on said extension; a slide block underlying and embracing the lower flange and reciprocable thereon; a movable jaw eccentrically pivotally mounted on the slide block opposite the fixed jaw; rods extending rearwardly of and anchored in the slide block at each side of the web, guides for said rods mounted on said beam; coiled springs on said rods interposed between the guides and slide block for forcibly projecting the movable jaw towards the fixed jaw to clamp the work therebetween; a pair of handle blocks independently slidably mounted on the top of the slide block at each side of the web, said handle blocks having recesses in their inner faces receiving and interlocking with the top flange and web of the beam to prevent removal therefrom, the upper ends of the handle blocks extending above the top of the beam to form handles for retracting the slide block; means for normally locking each handle block to the slide block; the lower flange having a series of holes therethrough; an inclined cam slot in each block; a cam slidable in each slot; an offset pin carried by each carn slidable in a bore therefor in the slide block and adapted to enter one of said holes in the flange when same register; means for normally urging the handle blocks forwardly of the slide block when the locking means is released; whereby when the handle blocks are retracted the springs will be compressed and the pins will be raised out of the holes in the flange and the locking means of the handle blocks will be engaged, and when the handle blocks are released the springs will force the slide block carrying the movable jaw into contact with the work, jolting the locking means into inoperative position, permitting the urging means to shift the handle blocks forwardly on the slide block thereby lowering the pins into the aligned hole in the lower flange.

11. In a wrench as set forth in claim 10, the lower end of the movable jaw being bifurcated; a pivot pin housed in said bifurcations; said movable jaw being rockably mounted on said pin and having a toothed convex front face whose axis is offset from the pin; and said movable jaw having a heel at its rear end normally separated from the lower rear end of the slide block thereby permitting the jaw to rock when engaged with an article clamped between the fixed jaw and movable jaw.

12. In a wrench as set forth in claim 11, said heel of the movable jaw engaging the lower rear end of the slide block only when the jaws engage the work and a clockwise rotative force is applied to the handle.

13. In a wrench as set forth in claim 11, the teeth being such that as the jaw is pivoted when in contact with the work, the axes of the teeth will pass through the approximate center of the work.

14-. In a wrench as set forth in claim 11, said slide block having an inclined bore in its lower end opening against the underside of the lower flange; a pin in said bore engaging the heel of the movable jaw to urge the movable jaw to pivot; and a spring in said inclined bore acting upon said pin, said pin serving as a decelerator for the slide after impact of the movable jaw with the work, also shifting the slide rearwardly on the flange, and serving to maintain constant pressure after impact of the movable jaw on the work.

15. In a wrench as set forth in claim 11, means for yieldably resisting the pivoting movement of movable jaw towards the work comprising a pawl adapted to engage a surface of the movable jaw adjacent the upper limit of the teeth thereon.

16. In a wrench as set forth in claim 11, said fixed jaw having an arcuate front face provided with teeth so disposed that the axes of said teeth intersect the approximate center of the work held by the wrench.

17. In a wrench as set forth in claim 10, said normally locking means comprising a lug on each handle block having a bore open at the top and underlying the upper flange, the lower end of the bore being reduced in diameter a reciprocable pin in the bore extending through said reduced end; and spring in the bore urging the pin downwardly to engage a hole in the top of the slide, said pin being releasable by the jolt of impact of the movable jaw against the work.

18. In a wrench as set forth in claim 10, said normally urging means comprising a rod on the rear end of each handle block extending rearwardly through a lug on the slide block and having its forward end secured to the rear face of the related handle block; a coiled spring around the rod interposed between the lug and block for yieldably urging the related block forwardly of the slide block until the rear end of the related cam slot is engaged by the related cam block, in which position the related pin will enter the hole in the lower flange.

References Cited UNITED STATES PATENTS 1,466,502 8/1923 Garbacz 8l-129 X 1,616,612 2/1927 Dodds 81-129 2,250,400 7/1941 Stephens 81129 X MILTON S. MEHR, Primary Examiner.