GB2273073A - Quick action bar clamp - Google Patents

Abstract

A quick action bar clamp has a first jaw 12 fixed to one end of a slide bar (14 Fig. 10) and a second moveable jaw 22 fixed to a body having a handgrip 18. Trigger handle 24 is operated by a users hand to urge the movable jaw along the slide bar by the action of a drive lever on the bar. A breaking lever 46 normally engages the slide bar to prevent reverse movement between the movable jaw and the slide bar but when it is pivoted towards the handgrip it disengages the slide bar to allow backward movement of the movable jaw relative to the slide bar. The two jaws face outwardly in opposite directions and operation of the clamp forces the two jaws apart. <IMAGE>

Description

QUICK ACTION BAR CLAMP This is a divisional of our co-pending patent application No. 9103238. 3 (Serial No. 2 241 4462) filed 15 February 1991.

This invention relates generally to a bar clamp 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 a quick-action bar clamp 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.

What is needed is a bar clamp 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.

SUMMARY OF THE INVENTION According to the invention, there is provided a hand tool as claimed in claim 1.

The invention will be described by way of example with reference to the accompanying drawings, in which: Figure 1 is a front view of a quick-action bar clamp embodying the invention; Figure 2 is a left end view to an enlarged scale of the quick-action bar clamp of Figure 1; Figure 3 is a right end view to an enlarged scale of the quick-action bar clamp of Figure 1; Figure 4 is a sectional view to an enlarged scale taken along the line 4-4 of Figure 3; Figure 5 is a view similar to Fig. 1 of an alternative 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 partial view of another embodiment of the bar clamp; Figure 9 is an elevational view of a further embodiment of the bar clamp;; Figure 10 is an exploded view of the element of the bar clamp shown in Figure 1; Figure 11 is a view of a still further embodiment of the invention; and Figure 12 is a partial cross-sectional view of a new embodiment of the invention.

With reference to the Figures, 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 16 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 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 handle grip 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 slot or 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 motion, indicated by the arrow 44, of the slide bar 14 when in operation. Any motion 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 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 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 motion 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. 4, 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 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 intended motion of the slide bar 14. Then the slide bar 14 is free to slide in either 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 user' s 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 4 of intended motion 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 intended motion 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 motion further compresses the spring 36 and in the process, by means of the binding interference between the lever 32 and bar 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 22 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 42 of any magnitude until the jaws 12, 32 come together, or a workpiece (not shown) is firmly gripped between them.

After the trigger handle 24 is fully pi.voted 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 ,aw 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 moving jaw 12 and the handle/grip assembly 18 are formed of halves which are held together by screws 66. The moving jaw 12 is held to the slide bar 14 by a pin 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 example, 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 show 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 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 '0 with that hand. Either the index or middle finger is in position to actuate the braking lever 46 as required while the other fingers encircle and contain the trigger handle 24 and handgrip 20.

As best illustrated in Figs. 2 and 3, the overall quick action bar clamp 10 in accordance with the invention is basically flat, takes 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 118, which includes no internal recess, and a basically U-shaped trigger handle 124. When the trigger handle 124 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 120. The end 150 of the braking lever 146 pivots in a recess 152 in the handle/grip assembly body 199. The trigger handle 124 pivots about an axis 126 and includes semi-circular tabs 170 which are recessed into correspondingly shaped slots 172 in the body 119.

A slightly modified embodiment of the bar clamp is shown in Fig. 8. There, the tabs 170 are retained in recessess 171 by the pressure of the spring 136 and the driving lever i32. Such arrangement substantially simplifies a process of assembly of the bar clamp as weil as the replacement of the trigger handle. To install the trigger handle 124 onto the assembly 118 end, and of the trigger handle having the tabs 170 is initially inserted between the driving lever 132 and a guide 175 of the body 119. Then, the trigger handle is pushed until the tabs 170 are engaged with the recesses 171 and the driving lever secures that position.

Fig. 9 best illustrates that a body 219 of an assembly 218 has a driving chamber 247 with a driving lever 232 and a spring 234, and a braking chamber having a braking lever 246. The braking lever 246 is positioned above a handle 220 and behind a trigger 224. The making chamber 245 is isolated from the driving chamber 247 by a separating member 249. One end 250 of the braking lever is pivotally positioned in a recess 252 situated near an upper part of the body 219. The use of the embodiment shown in Fig. 9 is especially recommended in the situation where preventing of inadvertent activation of the braking lever is desired.

In the embodiment of Fig. 1, the movable jaw 12 and the fixed jaw 22 are positioned on one side of the support assembly 18 and face each other. Therefore, activation of the driving lever 32 by the trigger handle 24 moves the slide bar 14 and the jaw 12 in the direction of the field jaw.

A modified bar clamp or a hand tool having the fixed jaw 22 and movable jaw 12 facing in opposite directions and extending from opposite sides of the assembly 18 is best shown in Figs. 10 and 11. In this embodiment the slide bar is inserted into the support assembly in such a way that the stop 60 positioned at one end thereof faces the braking lever 46 and the movable jaw 12 positioned at the other end of the slide bar faces the rear portion 43 of the support assembly.

In operation of this embodiment, when the trigger handle 24 is squeezed it activates the driving lever (not shown in Fig. 10 and 11) and incremently advances the movable jaw 12 connected to the slide bar 14 away from the fixed jaw 22.

In the standby position, the braking lever 46 engaging the slide bar 14 is transversely oriented to the slide bar at a slight angle. If a force is applied to the movable jaw in the direction of the arrow 44, the braking lever 46 presents no obstacle to the motion of the slide bar. However, if a force is applied te the movable jaw 12 in the direction opposite to the direction of the arrow 44, the engagement of the lever 46 and the surfaces of the slide bar 14 makes it impossible to withdraw the movable jaw 12 further away from the fixed jaw 22.

If it is desired that a workpiece is to be spread apart by the jaws 12 and 22, the movable jaw 12 is advanced away from the jaw 22 by activation of the trigger handle and driving lever.

Typically, the movable jaw is permanently mounted at one end of the slide bar, whereas the stop is fixedly positioned at the other end. However, if desired, the movable jaw 12 can be connected to the slide bar by means of a screw 72 or by any other suitable fastening means.

The stop 60 can also be attached to the slide bar by a thread or any other conventional means to facilitate its removal and/or replacement.

In this case, the hand tool shown in Fig. 1, having jaws facing each other, can easily be converted into the hand tool illustrated in the embodiment of Fig. 9 with the jaws facing in opposite directions. Steps of such, conversely are illustrated in Fig. 10.

In order to convert the tool, the screw connecting the movable jaw to the slide bar is loosened and the jaw removed from the bar.

Then, the stop is likewise released and taken out.

The movable jaw 12 is then positioned on the bar as illustrated in Fig. 11. The stop 60 is then positioned into an opening in the slide bar facing the braking lever. In this case, the threads of the openings in the slide bar which are adapted for the attachment of the removable jaw 12 and the stop 60 are compatible and generally positioned at equal distances (A and B) from the corresponding ends of the slide bar.

In Fig. 12 positioning of a trigger handle 324 rearwardly of a stationary handle 320 is illustrated.

The trigger handle pivots about an axis 326 and is provided with projected tabs 370 which are recessed in correspondingly shaped projections 372 in the body 319.

During operation, fingers of one hand of a user surround the handle 320 while the trigger 324 is activated by the palm of the same hand.

Claims (11)

CLAIMS:

1. A hand tool comprising a fixed jaw; a movable jaw, said fixed jaw and movable jaw facing in opposite directions; a slide bar, said movable jaw being mounted on one end of said slide bar, said slide bar being movable to bring said movable jaw toward and away from said fixed j aw; support means for supporting said slide bar, said fixed jaw being connected to said support means; one-way drive means for releasably engaging and, when engaged, for advancing said slide bar and attached movable jaw said movable jaw being subject to advancement away from said fixed jaw when said one-way drive means is disengaged;; said one-way drive means having a driving lever, and a braking lever normally engaging said slide rod, said braking lever when engaging said slide bar preventing motion of said movable jaw toward said fixed jaw, said braking lever having an engaging portion extending outwardly from said support means, a trigger handle pivotably mounted to said support means and contacting said driving lever, said engaged driving lever moving said slide rod and said movable jaw away from said fixed jaw.

2. A hand tool as claimed in claim 1, wherein said support means including a handgrip, a trigger-type relationship existing between said trigger handle and said handgrip, said bar clamp being holdable at said handgrip, said braking lever and the trigger handle being selectively operable by the same hand in such a manner that one of the index and middle fingers is positioned on the engaging portion of the braking lever to actuate the braking lever, while the other fingers encircle and contain the trigger handle and the handgrip.

3. A hand tool claimed in claim 1, wherein said slide bar and said movable jaw move together and being subject to reciprocal motion toward and away from said fixed jaw when said one way drive means is disengaged by application of external forces to said braking lever, said slide bar being capable of moving said movable jaw in continuous motion.

4. A hand tool as claimed in claim 1, wherein said one-way drive means advances said movable jaw away from said fixed jaw in increments.

5. A hand tool as claimed in claim 1, wherein said braking lever has one end thereof pivotably connected to said support means, and further including first bias means for urging said braking lever into said engagement with said bar, movement of said movable jaw toward said fixed jaw being prevented by said engagement, said braking lever being subject to release from engagement with said slide bar by application of an external force to said engagement portion of said braking lever, said force counteracting said first bias means and pivoting said braking lever.

6. A hand tool as claimed in claim 5, wherein said driving lever is normally disengaged from said slide bar, and pivoting said trigger handle in first direction from a standby position forces said driving lever into engagement with said slide bar, said engaged driving lever moving said slide bar and said movable jaw away from said fixed jaw.

7. A hand tool as claimed in claim 6, wherein said one-way drive means further includes second bias means for normally urging said driving lever out of engagement with said slide bar and for returning said trigger handle in the direction opposite to said first direction to said standby position.

8. A hand tool as claimed in claim 6, wherein the distance of said slide bar advance for each actuation of said handle is directly related to the magnitude of handle motion.

9. A hand tool as claimed in claim 6, wherein said engagements between said levers and said slide bar result from mechanical interference with binding between said bar and levers.

10. A hold down clamp system substantially as hereinbefore described with reference to the accompanying drawings.

11. A hand tool substantially as hereinbefore described with reference to the accompanying drawings.