GB2221641A

GB2221641A - Quick-action clamps

Info

Publication number: GB2221641A
Application number: GB8912692A
Authority: GB
Inventors: Joseph Alan Sorensen; Dwight Leonard Gatzemeyer
Original assignee: Petersen Manufacturing Co Inc
Current assignee: Petersen Manufacturing Co Inc
Priority date: 1988-08-09
Filing date: 1989-06-02
Publication date: 1990-02-14
Anticipated expiration: 2009-06-02
Also published as: BE1003185A5; FR2635289A1; CY1745A; GB8912692D0; HK134593A; NL8901856A; ES2014369A6; DE3917473C2; CN1034318C; CN1040342A; IE63977B1; BR8903624A; NL193057C; DE3917473A1; DK173524B1; NL193057B; IE892111L; FR2635289B1; DK368089D0; IT1231639B

Description

1 QUICK-ACTION CLAMU e') ( 1 1 11 't, J J t , 'LL, L 1 C) r 1

This invention relates generally to clamps of the type used to temporarily clamp together two articles, for example, for gluing, or to hold a workpiece for welding, and more particularly to quick-action clamps wherein the moving jaw can be rapidly advanced or advances in small increments of selectable length. The concept of a bar clamp is old and well-known. In recent years, over-center toggle action handgrips have been incorporated for use in final tightening against the workpiece, for example, in U.S. Patents 4,088,313 by Pearson and 4,563,921 by Wallace. A disadvantage in the prior art lies in the fact that adjustment in the moving jaw over a substantial distance is cumbersome and imprecise. Frequently, the moving jaw is entirely disengaged and free to move until the final tightening of an object between the movable and fixed Jaws is accomplished. A third hand would be helpful.

The concept of a C-clamp is also old and well-known. A Cshaped frame holds a fixed jaw, and a moving jaw is advanced toward the fixed jaw or retracted therefrom by rotation of a threaded shaft to which the moving jaw is mounted. A isadvantage of this arrangement lies in the fact that when the moving jaw has a substantial distance to travel before clamping 2 upon the workpiece or workpleces, a great number of turns is required on the threaded shaft supporting the moving jaw. Frequently, the handle for turning the shaft is a slide-type handle, moving transversely to the direction of shaft motion so that the handle can be slipped back and forth through the shaft with each half turn of the shaft. This is advantageous, where turning must be accomplished in a tight spot and a full -3600 swing of the handle is not possible. However, slide-shifting of the handle is awkward and bothersome. Bar clamps using a threaded rod for adjustment have similar problems.

What are needed are clamps having a moving jaw which is rapidly movable over both short and long distances to clamp against a workpiece and is operable using one hand with complete control by the operator at all times.

Generally speaking, in accordance with the invention, Cand bar clamps especially suitable for rapid and precise closure against a workpiece are provided. The bar clamp includes a fixed jaw and a movable jaw opposing the fixed jaw. The movable jaw connects at one end to a slide rod which Is movable to bring the movable jaw toward and away from the fixed jaw. one-way drive means, by operation of a trigger handle grip, releasably engages the slide bar and advances the movable jaw toward the fixed jaw. The one-way drive means is incapable of moving the slide bar and 3 wovable jaw away from the fixed jaw. Return notion of the iaovable jaw is accomplished manually when the one-way drive means is disengaged. A first braking lever which is biased to bind acjainst the slide bar prevents reverse inotion of the movable jaw away from the fixed jaw, except when the first lever is disengaged from the slide bar. Thus, for return motion of the jaw, It is necessary that both the one-way drive means and the first braking lever be disengaged. The trigger handle advances the slide bar by driving a second lever which binds against a surface of the slide bar and moves the rod as the second lever imoves toward the fixed jaw. The second lever is returned by spring force to its original position after each stroke of the trigger handle, the second lever sliding over the bar surface during its return motion.

The C-clamp includes a fixed jaw and a movable jaw opposing the fixed jaw. The movable jaw connects at one end to a slide rod which is movable to bring the movable jaw toward and away from the fixed jaw. A C-shaped frame includes a longitudinal bar parallel with the slide rod; a first arm is attached transversely to the longitudinal bar and extends to support the fixed jaw. A second arm attached transversely to the bar extends to slidably support the slide rod. one-way drive means, by operation of a trigger handle grip, releasably engages the slide rod and advances the movable jaw toward the fixed jaw. The one-way drive ineans Is incapable of moving the slide rod and movable Jaw away from the fixed jaw. Return motion of the movable jaw is 4 accomplished manually when the one-way drive means is disengaged. A first lever which is biased to bind against the slide rod prevents reverse notion of the movable jaw away from the fixed jaw, except when the first lever is disengaged from the slide rod. The trigger handle advances the slide rod by driving a second lever which binds against the surface of the slide rod and moves the rod as the second lever moves forward. The second lever is returned by spring force to its original position, the second lever sliding over the rod surface during its return notion. There is no handle to rotate in a plane transverse to the notional direction of the moving jaw as in the prior art.

Thus the invention provides improved quick-action bar and C-clamps wherein themoving jaw may be moved over short and long distances rapidly. Also, the moving jaw may br. incrementally and precisely advanced from any position and may be advanced in increments of selectable length for each action of a driving handle.

Advantageously the movable jaw does not move its weight when the clamp is in a vertical position.

Further advantages are that clamp operation can be eAT.4eu-1a-4le ue go 1C -fiTl o:l aielTuTs maT,& L. sT g 9;rnbTa :C eanúTI JO l-Y OUTT 3qI 5U012 uaxe:l aluos P016alejua ule 0:1 M3TA 112UOT-40as v OT 1, ainúTA 91 aanBTj go dmula aeq uoTloe-3[oTnb aq-4 go aluos pa5alelua un o-4 kieTA pue:;q5Ta ie sT c ainBT,1 :1 ain.BTI go duelo aeq uol4ou-XoTnb aqI go aleos paBxLIua ue ol inaT,& pue -4jal v sT Z 9;zn.6Tj !UOT4U0AUT Oql tnTK 0OURPaOOOLuT dutielo xeq uoTloie-Xc)Tnb le go may& - 4uo-Tj v sT -c aanfiTI :SBUTMUIP 0111 111 -s4u@w-cpocltuo pa-iaajaad jo Uo-C-4d-rIZ)Sap paIT2-40p BUTMO110j 011-4 maj -4uo-it2cl(IL, oq ITTM UOTq1.10AUT aq4 gO SDS2qUI2API? 1011-40 -saopds M011121-1 UT a-4ea@do ueo UOTqUaAUT a44 Mq1M aOUUPIOODR 1IT pueaccl -.1t2T3 11-40q I'MC PUCII otio 111TM polls TT (-1111003t? 6 embodiment of a quick-action bar clamp In accordance with the invention; Figure 6 is a section view taken along the line 6-6 of Figure 5; Figure 7 is a sectional view taken along the line 7-7 of Figure 5; Figure 8 is a front view of a quick-action c-clamp in accordance with the invention; Figure 9 is a top view of the quick-action C-clamp of Figure Figure 10 is a right end view of the quick-action C-clamp of Figure 8; and Figure 11 is a fragmentary view, to a larger scale, similar to Figure 8 showing operation of the quick-action C-clamp.

With reference to Figures 1-7, a quick-acting bar clamp 10 includes a movable jaw 12 connected to a slide bar 14. The slide.bar is slidably supported in a slot 16 (Fig. 4) which passes through a handle/grip assembly 18.

The handle/grip assembly 18 includes a body 19 through which the slot passes, a handgrip 20 attached to the body 19 on one side of the slot 16, and a fixed jaw 22 attached to the body 19 1 7 on the other side of the slot 16. A trigger handle 24 is pivotably mounted to the body 19 adjacent the slot 16 by means of a pivot pin 26. The moving jaw 12 opposes the fixed jaw 22.

As best illustrated in Fig. 4, the handgrip 20 is hollow in part so as to receive the trigger handle in the cavity 28. A second cavity 30 In the body 19 divides the bore 16. A driving lever 32 is suspended on the slide bar 14 which passes through a hole 34 in the driving lever 32. A spring 36 is compressed between the driving lever 32 and a surface 38 of the cavity 30 urging the driving lever 32 against the upper end 40 of the trigger handle 24. The upper end 40 of the trigger handle 24 is forked and straddles the slide bar 14. Force of the spring 36 urges the trigger handle 24 against an inner surface 42 of the body 19 thus providing a standby condition. In the standby condition, the driving lever 32 is positioned perpendicular to the direction of notion, indicated by the arrow 44, of the slide bar 14 when In operation. Any notion of the handle 24 about the pivot pin 26 in the direction of the arrow 44 is accomplished against the bias of the spring 36.

A braking lever 46 is suspended from the slide bar 14 which passes through an opening 48 in the braking lever 46. One end 50 of the braking lever 46 is pivotably captured in a recess 52 within the body 19 such that the braking lever 46 may pivot within the constraints defined by the surfaces of the recess 52 and by binding of the braking lever 46 with the slide bar 14 when the edges of the opening 48 in the lever 46 engage the surface of 8 the slide rod 14. A spring 54 seats In a recess 56 in the body 19 and biases the free end of the braking lever 46 away from the trigger handle 24. The biased position of the braking lever 46 is limited by the binding Interference between the opening 48 of the lever 46 with the slide bar 14.

It should be noted that in the standby position illustrated in Figure 4, the driving lever 32 Is substantially perpendicular to the longitudinal axis of the slide bar 14, whereas the portion of the braking lever 46, which engages the slide bar 14, is transverse to the longitudinal axis of the bar 14 but not perpendicular thereto. In this condition, if a force is applied to the moving jaw 12 in the direction indicated by the arrow 44, the slide bar 14 is free to move through the hole 34 in the driving lever 32 and through the spring 36. Because the braking lever 46 is free to pivot against the bias of the spring 54 when force is applied on the moving jaw 12 in the direction of the arrow 44, the braking lever 46 presents no obstacle to this notion of the slide bar and the moving jaw 12 may be advanced continuously toward the fixed jaw 22.

However, in the standby position as illustrated In Fig. 40 if a force Is applied to the movable jaw 12 in the direction opposite to the direction indicated by the arrow 44, the edges of the opening 48 in the lever 46 bind against the surface of the slide bar 14 and it is not possible, without further action, to withdraw the moving jaw farther away from the fixed jaw 22, as described more fully hereinafter. Compression of the spring 56 4 9 by pressing on the braking lever 46 in the direction of the arrow 44, allows withdrawal of the slide bar 14 and movable jaw 12 away from the fixed jaw 22. This force brings the end 50 of the lever 46 into perpendicularity with the direction of the intended motion of the slide bar so that the slide bar 14 is free to slide in eitlier direction through the opening 48 in the braking lever 46.

The trigger handle 24 is squeezed in the direction indicated by the arrow 44 to incrementally advance the slide bar 14 with its attached movable jaw 12 toward the fixed jaw 22. when the handle 24 is squeezed between a userls hand (not shown) and the handgrip 20, pivoting occurs about the pivot pin 26 and the end 40 of the trigger handle 24 moves in the direction of the arrow 44. This causes the driving lever 32 to pivot about its upper end (Fig. 4), so that the driving lever 32 is no longer perpendicular to the direction 44 of intended notion of the slide bar 14. Pivoting the driving lever 32 compresses the spring 36 and also causes the edges of the hole 34 through the driving lever 32 to bind against the surface of the slide rod 14. Binding occurs because the driving lever 32 is no longer perpendicular to the direction 44 of the intended notion of the slide bar 14. Further motion of the trigger handle 24 causes the driving lever 32 to translate in the direction of the arrow 44. This notion further compresses the spring 36, and in the process, by means of the binding interference between the lever 32 and rod 14, advances the bar 14 and its connected movable jaw 12 toward the fixed jaw 22. The maximum distance of advance of the movable Jaw 12 with one stroke of the trigger handle 24 is limited when the spring 36 Is fully compressed or, in an alternative construction, the handle 24 strikes the inner surface 58 of the handgrip 20.

However, the stroke of the trigger handle 24 can be through any lesser arc, thereby diminishing the distance the movable Jaw 12 travels In a single stroke in proportion to the angle of the trigger handle stroke. Additional strokes may be applied to the trigger handle 24 of any magnitude until the jaws 12, 22 come together or, a workpiece (not shown) is firmly gripped between them.

After the trigger handle 24 is fully pivoted in the direction of the arrow 44 about the pivot pin 26, release of the trigger handle 24 causes the return of the trigger handle 24, driving lever 32 and spring 36 to the position shown in Fig. 4 as a result of the compressive forces in the spring 36 urging the components toward the movable Jaw 12.

A transverse pin 60 passing through the free end of the slide bar 14 prevents withdrawal of the slide bar 14 from the slot 16 when the braking lever 46 is pressed in the direction of the arrow 44 and the movable Jaw 12 is manually drawn away from the fixed Jaw 22. It should be noted that operation of the trigger handle 24 is ineffective in accomplishing any motion of the slide bar 14 in the direction opposite to the arrow 44.

For illustrative purposes only, protective pads 62 are shown attached to the jaws 12, 22. Also for illustrative purposes, the 11 inoving jaw 12 and the handle/grip assembly 18 are formed of halves which are held together by screws 68. In the illustrated embodiment (Fig. 4) In accordance with the invention, the slide bar 14 has a rectangular cross- section. In alternative embodiments in accordance with the invention, the slide bar 14 may be any shape, for examples, square, round, triangular, and the openings 34, 48 in the levers 32, 46, respectively are appropriately shaped for proper binding interference with the slide bar 14.

In summary, if it is considered that a workpiece is to be clamped between the jaws 12, 22, the movable jaw 12 can be advanced toward the fixed jaw 26 either in one continuous motion, merely by pushing in the direction of the arrow 44 on the movable jaw 22 or, by operating the trigger handle 24 In a series of strokes of length to be determined by the user. Large strokes may be used at first and small strokes later as the desired pressure is applied to the workpiece. During this advancing operation, the braking lever 46 prevents any backward motion of the slide bar 14 after each advance has been completed. While the braking lever 46 holds the bar 14, the trigger handle 24 is released. The spring 36 then returns the handle 24 and driving lever 32 to the positions shown in Fig. 4, ready for another stroke. At any time when the user desires to retract the movable jaw 12 away from the fixed jaw 22, for example, to release a workpiece or to open the bar clamp to receive a workpiece, it Is only necessary to pull on the movable jaw 12 in the direction

1 12 opposite to the arrow 44 while simultaneously compressing the spring 54 by pressing on the braking lever 46 in the direction of the arrow 44.

It should be noted that all operations of the trigger handle 24 and braking lever 46 can be accomplished with the same hand while holding the bar clamp 10 with that hand. Either the index or middle finger is In position to actuate the braking lever 46 as required while the fingers encircle and contain the trigger handle 24 and handgrip 20.

As best illustrated In Figures 2 and 3, the overall quickaction bar clamp 10 in accordance with the invention is basically flat, takes up little space, and can be operated in tight places. Slide bars 14 of different lengths may be used.

In Figs. 1-4, the handle/grip assembly 18 is formed of halves which are held together by screws 66 and the trigger handle 24 is solid and slips into the cavity 28 in -the handgrip 20. In an alternative embodiment (Figs. 5-7), a quick-action bar clamp 110 In accordance with the Invention includes a one-piece handle/grip assembly lie, which includes no internal recess, and a basically U-shaped trigger handle 124. When the trigger handle 124 is squeezed against the handgrip 120, as will be apparent in Fig. 7, the handle 124 moves in the direction of the arrow 144 and straddles the handgrip 102. The end 150 of the braking lever 146 pivots in a recess 152 in the handle/grip assembly body 119. The trigger handle 124 pivots about an axis 126 and includes semicircular tabs 170 which are recessed into correspondingly 13 shaped slots 172 In the body 119.

operation of the bar clamp of Figs. 5-7 is the same as that for the embodiment of Figs. 1-4, taking note that the reference numerals in Figs. 5-7 correspond with those numerals used in describing Figs. 1-4, with addition of 100 thereto.

With reference to Figures 8-11, a quick-acting C-clamp 210 includes movable jaw 212 connected to a slide rod 214. The slide rod 214 is slidably supported in a bore 216 through a C-shaped frame 218.

The C-shaped frame 218 includes a horizontal bar 220, a first transverse arm 222, and a second transverse arm 224 which supports the slide rod 214 and constitutes a handgrip. A fixed jaw 226 opposing the movable jaw 212 is fixedly connected to the arm 222.

The slide rod 214 terminates in an engagement er 228 used for advancing and withdrawing the movable jaw 212 as described more fully hereinafter.

A transverse opening 230 is formed through the arm 224 dividing the bore 216 into two portions. A driving lever 232 Is suspended on the slide rod 214 which passes through a hole 234 in the driving lever 232. A spring 236 is compressed between the driving lever 232 and a surface 238 of the opening 230 urging the driving lever 232 against an opposite surface 240 of the opening 230.

A trigger handle 242 pivotably mounts to the C-clamp arm 224 by a pivot pin 244, and an end 246 presses against the rear surface of the driving lever 232. Thus, the lever 232 is acted 14 on one side by the spring 236 and on the other side by the trigger handle 242. The spring 236 urges the driving lever 232 into the position Illustrated in Figure 8 against the surface 240 when in a standby state, and in that way forces the trigger handle 242 to pivot around the pin 244 to the position illustrated. Any notion of the trigger handle 242 in the direction of the arrow 248 is accomplished against the bias of the spring 236.

A braking lever 250 is suspended from the slide rod 214 which passes through an opening 252 in the braking lever 250. one end 254 of the lever 250 is pivotably captured in a recess 256 in the transverse arm 224, such that the braking lever 250 may pivot within constraints defined by the surfaces of the recess 256 and binding of the lever 250 with the slide rod 214, where the edges of the opening 252 engage the surface of the slide rod 214. A spring 258 seats in a recess 260 formed into the end of the C-shaped frame 18 and biases the braking lever 250 at its free end away from the transverse arm 224, leaving a gap 262 therebetween.

It should be noted that In the standby position illustrated in Figure 8, the driving lever 232 is substantially perpendicular to the longitudinal axis of the slide rod 214, whereas the portion of the braking lever 252, which engages the slide rod 214, is transverse to the longitudinal axis of the rod 214 but not perpendicular thereto. In this condition, if a force is applied to the engagement member 228 in the direction indicate- cl by tlic is arrow 264, the slide rod moves freely through the hole 234 in the driving lever 232 and through the spring 236. Because of the cant of the braking lever 250 relative to the direction of motion 264, the braking-lever 250 presents no obstacle to this motion of the slide rod and the moving jaw 212 may be advanced continuously toward the fixed jaw 226.

However, in the standby position as illustrated, if a force is applied to the engagement member 228 in a direction which is opposite to the direction indicated by the arrow 264, the edges of the opening 252, urged by the spring 258, bind against the surface of the slide rod 214 and it is not possible, without further action, to withdraw the moving jaw further away from the fixed jaw 226, as described more fully hereinafter. This further action, which allows withdrawal of the slide rod and movable jaw 212 away from the fixed jaw 226, is compression of the spring 258 by pressing on the braking lever 250 in the direction of the arrow 264. This brings the end 254 of the lever 250 into perpendicularity with the direction of Intended notion of the slide rod 214. Then the slide rod is free to slide In either direction through the opening 252 in the braking lever 250.

The trigger handle 242 is squeezed in the direction indicated by the arrow 248 in order to incrementally advance the slide rod 214 with its attached movable jaw 212 toward the fixed jaw 226. When the handle 242 is squeezed between a user-s hand (not shown) and the transverse arm 224, pivoting occurs about the pivot pin 244 and the end 246 of the trigger handle 242 moves In 1 16 the direction of the arrow 264. This causes the driving lever 232 to pivo t about its upper end 266 so that it is no longer perpendicular to the direction 264 of intended motion of the slide rod 214. Pivoting the driving lever 232 compresses the spring 236 and also causes the edges of the hole 234 through the d-rive lever 232 to bind against the surface of the slide rod 214 causing the drive lever 232 to translate in the direction 264.

This notion further compresses the spring 236, and in the process, by means of the binding interference between the lever 232 and rod 214, advances the rod 214 and its connected movable jaw 212 toward the fixed jaw 26. (Fig. 11). The maximum distance of advance of the movable jaw 212 with one stroke of the trigger handle 242 is limited when the lever 232 is translated until it rests against the surface 268 of the transverse opening 230 or the trigger handle 242 hits a stop (not shown) on the frame 218.

liowever, the stroke of the trigger handle 242 can be through any lesser arc thereby diminishing the distance the movable jaw travels in proportion to the angle of the trigger handle stroke. Additional strokes may be applied to the trigger handle 242 of any magnitude until the jaws 212, 226 come together or, a workpiece (not shown) Is firmly gripped between them.

in summary, if it is considered that a workpiece is to be clamped between the jaws 212, 226, the movable jaw 212 can be advanced toward the fixed jaw 226 either in one continuous notion, merely by pushing In the direction of the arrow 264 on

17 the engagement member 228 or, by operating the trigger handle 242 in a series of strokes of length to be determined by the user. Large strokes may be used at first and smaller strokes later as the desired pressure is applied to the workplece. During this advancing operation, the braking lever 250 prevents any backward inotion of the slide rod 214 after each advance has been completed. While the braking lever 250 holds the rod 214, the trigger handle 242 is released. The spring 236 then returns the handle 242 and driving lever 232 to the positions shown in Fig. 8, ready for another stroke. At any time when the user desires to retract the movable jaw 212 away from the fixed jaw 226, for example, to release a workpiece or to open the C-clamp to receive a workpiece, it is only necessary to pull on the engagement member 228 in thedirection opposite to the arrow 264, while simultaneously pressing on the braking lever 250 In the direction of arrow 264.

It should be noted that all operations of the trigger handle 242 and braking lever 250 can be accomplished with the same hand while holding the C-clamp 210 with that hand. The thumb Is in position to actuate the braking lever 250 as required while the fingers encircle and contain the trigger handle 242 and transverse arm 22.4.

As best illustrated in Figures 9 and 10, the overall quickaction C-cfamp 210 in accordance with the invention is basically flat, takes up little space, and can be operated in tight places. The frame 218 can be of any conventional shape as used with Cclamps of the prior ar-t, and the length of transverse arms 222, 18 224 nay be varied as well as the angles which they assume irelative to the direction of motion of the sliding rod 214.

It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efficiently attained and, since certain changes may be made in the above construction without departing from the scope of the Invention, It is Intended that all matter contained in the above description or shown in the accompanying drawings, shall be interpreted as illustrative and not In a limiting sense.

LB010689

Claims

19 1. A quick-acting clamp comprising a fixed jaw, and an opposing movable jaw, the movable jaw being attached to one end of a slide which is movable to carry said movable jaw toward and away from said fixed jaw, and the fixed jaw being connected to support means for supporting said slide, and one-way drive means for releasably engaging and, when engaged, for advancing said slide and attached movable jaw from a first position to a second position closer to said fixed jaw.

2. A quick-acting clamp as claimed in claim 1 wherein when the one-way drive means is disengaged the slide and attached movable jaw are capable of continuous motion toward and away from the fixed jaw by application of external force to the slide.

3. A quick-acting clamp as claimed in claim 1 or 2 wherein the one-way drive means includes a braking lever which normally engages the slide to prevent motion of the movable jaw away from the fixed jaw.

4. A quick-acting clamp as claimed in claim 3 wherein the braking lever has one end pivotably connected to the support means, and further including first bias means 11 LB010689 for urging the braking lever into engagement with the slide, withdrawal of the movable jaw away from the fixed jaw being prevented by said engagement, the braking lever being subject to release from engagement with the slide by application of an external force to the other end of the braking lever to counteract the first bias means and pivot the braking lever.

5. A quick-acting clamp as claimed in claim 3 or 4 wherein the one-way drive means includes a driving lever normally disengaged from the slide, and a trigger handle mounted on the support means and contacting the driving lever, movement of the handle in a first direction from a standby position forcing the driving lever into engagement with the slide thereby moving the slide and the movable jaw toward the fixed jaw.

6. A quick-acting clamp as claimed in claim 5 wherein the one-way drive means further includes second bias means for normally urging the driving lever out of engagement with the slide, and for returning the trigger handle in a direction opposite to the aforesaid first direction to the standby position after the trigger handle is released.

7. A quick-acting clamp as claimed in claim 6 wherein the first and second biasing means are springs.

LB010689 21

8. A quick-acting clamp as claimed in claim 6 or 7 wherein the distance of slide advance for each actuation of the handle is directly related to the magnitude of handle motion.

9. A quick-acting clamp as claimed in any of claims 5 to 8 wherein the engagement between the respective levers and the slide result from mechanical interference between the slide and the levers.

10. A quickacting clamp as claimed in any of claims 5 to 9 wherein the slide passes through respective openings in each of the levers and the engagement therebetween results from binding of the surface of the slide with edges of each of the openings.

11. A quick-acting clamp as claimed in any of claims 5 to 10 wherein the support means includes a handgrip whereby the clamp can be held and the handle is positioned for operation concurrently by the same hand.

12. A quick-acting clamp as claimed in claim 11, wherein the other end of the braking lever is positioned adjacent the handgrip and the handle such that the clamp can be supported and one of the handle and the braking lever can be selectively operated by an operator using one hand and gripping said grip.

LB010689 22

13. A quick-acting clamp as claimed in any preceding claim wherein the support means is a C-shaped frame including a longitudinal bar, a first arm attached transversely to the bar and extending to support the fixed jaw, a second arm attached transversely to the bar and extending to support the slide, the end of the slide away from the moving jaw extending beyond the C-shaped frame and including engagement means for applying external force to the slide.

14. A quick-acting clamp as claimed in claim 13 wherein the bar and arms of the C-frame are integral.

15. A quick-acting clamp substantially as hereinbefore described with reference to and as illustrated in Figs. 1 to 4, or Figs. 5 to 7, or Figs. 8 to 11 of the accompanying drawings.

1>ublishediggOatTlie Patent Office. StateHouse.66 71 High Holborn. London WC1R4TP. Further copies inaybeobtainedfrom The Patent OfficeSales Branch, St MarY CraY. orpingtor- Kei.t BR5 SP.D- Pr,red' by MjItIplex techmques Itc. St Mary Cray, Kent. Con. 1,'87