CLAMPING DEVICE

Abstract: A clamping device comprising a support structure (1) carrying a first jaw (3) which is fixed relative to the support structure and a movable jaw (6) capable of moving towards the fixed jaw to effect clamping. The movable jaw is operated by a lever (10) which engages an advancing means wherein said lever incorporates a locking means to secure the movable jaw at any given position and applied force.

Description: TITLE: ΓΠΓJ MPTNG DEVICE Field of the Invention: This invention relates to clamping devices such as vices for the clamping of workpieces between a pair f x 5 of clamping jaws at a safe and comfortable height. Background of the Invention: The most common clamping device in current use is the vice having a fixed jaw and a moving jaw carried by a threaded support engaged by a correspondingly 10 threaded shaft for advancing the moving jaw to clamp a workpiece between the two jaws. Most vices are made from machined cast steel and must be .bolted to a work bench or other support. For this reason, most vices are not easily portable from one working site to 15 another. A number of portable clamping devices have been proposed to enable a workman or handyman to conveniently transport the device from one work site to another. One such proposal is shown in European 20 Patent Publication 64883 (82302408.8). This clamping device has an adjustable jaw which is fixed during the clamping operation, and a moving or clamping jaw actuated by a foot operated lever which pivots the jaw from a released position to a clamping position via an 25 overcentring linkage pivoted to the lever and to the moving jaw to lock the moving jaw in its fully clamped position. While the arrangement described in the above document has the advantage of portability, it does not allow different appropriate clamping forces to be applied depending on the object being clamped and the clamping range is not quickly adjustable, some degree of trial and error being required. Thus, unless the operator's foot is kept on the pedal to apply variable clamping forces lower than that necessary to cause the locking linkage to overcentre, only one clamping force may be maintained on a clamped object using this device, and this force may in many instances be excessive and damage the object being clamped or inadequate and allow the object to slip while being worked on. Another type of clamping device is described in U.K. Patent Application 2187411. In the device shown in Figures 25 to 29, a moving jaw is operated by a spring loaded foot lever to apply a clamping force dictated by the force applied by the operator's foot. However, the operator's foot must be kept on the lever otherwise the spring releases the clamping jaw. This arrangement seriously restricts the activities which may be performed by the operator on the clamped object. Statement of Invention and Objects: It is an object of the present invention to provide an improved lever operated clamping device which may be mounted on a portable support and which is capable of the finely controlled application of a wide range of clamping forces to a wide range of different sized objects without the need for the operator to maintain contact with the operating lever. It is a secondary object to provide an improved mechanism for rapidly advancing the jaw or jaws to the clamping position and to provide automatic locking at that position. It is a still further object to provide a rigid supporting structure for the clamping device which may be collapsed into a form which is convenient for carrying. According to one aspect, the present invention provides a clamping device comprising a support structure carrying two adjustably spaced apart jaws, lever means pivotally connected to the support structure and operably engaging advancing means for moving the two jaws relative to each other as the lever means is pivoted to apply a variable clamping force to an object between said jaws determined by the force applied to the lever, and locking means for restraining the portion of the two jaws in any desired position and with the said desired clamping force applied to the object. In the preferred form there is a fixed jaw and a movable jaw, and advancing means operating to move said movable jaw towards said fixed jaw. The fixed jaw may be repositioned in position between clamping operations. The locking means preferably has associated means for deactivating the locking means whereby the lever means may be reciprocated to repeatedly actuate the advancing means to advance the movable jaw towards the fixed jaw. In this way, the clamping device may be operated in the manner of a press to press fit bushes or bearings into housings or, with suitable attachments to the jaw faces, it can be used for the controlled bending of metallic members. In the activated condition, the locking means operates to hold the movable jaw in any advanced position to which it is moved by the lever means. B y using a locking means which restrains the movable jaw in any desired position, a wide range of clamping forces may be applied to an object without the need for the operator to maintain contact with the operating lever. The lever means is preferably spring biased to return to its rest position upon release of the lever. The movable jaw may be completely removable from the support structure and reversible to facilitate a much wider clamping capacity. In one preferred form, the locking means is operative to lock the lever near the operative end of the lever rather than near the advancing means end of the lever. The advantage of this arrangement is that the locking action is applied at the end of the lever at which the lowest forces are required whereby the locking action performed by the locking means is less onerous than would be the case in the presence of the higher forces required at the advancing means end of the lever. In its presently preferred form, the locking means comprises a plate pivoted to the support structure and having an aperture through which a rod connected to the lever means is free to pass when they are perpendicular to each other, said plate being normally spring biased to an angular position with respect to the rod, so that the edges of the aperture in the plate grip the rod when advancing movement of the lever ceases, to prevent return movement of the lever to thereby lock the advancing means and the moving jaw in any desired position, said locking means having associated means for releasing the locking means when clamping is no longer required. Alternatively, the locking means may comprise a simple clamp, wedge, cam, ratchet or friction grip mechanical means to restrain the lever means or moving jaw in any desired position or at any desired clamping force. The lock releasing means may comprise a secondary lever pivoted to the support structure and having an abutment means positioned to engage the plate of said locking means to hold said plate in an orientation substantially perpendicular to the rod to allow the rod to slide freely through the aperture. One of the advantages of this form of locking means is that release may be achieved without further force being applied to the lever means. In this way, delicate articles, such as ceramic tiles, may be clamped between the jaws and then released without damage. When the plate is held in its released position, and the lever means be in its rest position, the moving jaw may be advanced along the support structure towards the fixed jaw by hand. Alternatively, with the plate in the released position, and by pumping the lever means repeatedly against the action of the spring biasing, the moving jaw may be advanced with great power. The moving jaw is preferably carried by an elongate back runner configured to engage a track formed in the supporting structure and having an array of apertures formed along the length of the lower face of the back runner, said advancing means including an advancing member having one or more upstanding pawls positioned to engage the apertures in the lower face of said back runner, said advancing member being pivoted to the end of said lever means and being spring biased to cause arcuate movement of said advancing member towards the lower face of said back runner to cause engagement between said pawl(s) and said array of apertures when the lever means is pivoted in the operative direction, and an abutment finger carried by said support structure for engaging the rear end of said advancing member when the lever is in its rest position to pivot the advancing member against the action of said spring biasing to position the pawls clear of the lower face of the back runner to facilitate free sliding movement of said moving jaw with respect to said support structure. The pawls may, if desired, be formed with an undercut portion at their leading faces configured to engage the inner surface of the back runner surrounding the aperture engaged by each pawl to ensure positive engagement with said back runner. In a particularly preferred form of the invention, the support structure comprises a central elongate support defining a track for slidably retarding the moving jaw, and at least three support legs pivotably attached to the elongate support and comprising at least two legs pivoted to the elongate support at the front of the support and at least one leg pivotably mounted at the rear end of the support, and collapsible bracing struts extending between said front legs and between said front leg bracing strut and said rear leg to releasably retain said legs in their supporting positions, said front legs being collapsible to lie along either side of the elongate support and said rear leg, lever arm and pedal being collapsible to lie along the length of the support to facilitate collapsing of the support structure into an easily transportable or stowable form. The front legs preferably have enlarged feet secured to their lower ends and to which the bracing struts are pivotably attached, said feet being positioned to enable the operator to stand on the feet to stabilise the support structure. In another aspect, the invention provides a clamping device comprising two adjustably spaced apart jaws carried by a support structure, pivoted lever means carrying advancing means for advancing at least one of said jaws relative to the other jaw, said advancing means including an advancing member having means to engage spaced apertures, teeth or abutments in an elongate back runner of one of said jaws, said advancing member being pivoted to the inner end of said lever means and being spring biased to cause arcuate movement of said advancing member towards the back runner to cause engagement between said engagement means and said spaced apertures, teeth or abutments when the lever means is pivoted in the operative direction, and an abutment finger carried by said support structure for engaging the rear end of said advancing member when the lever is in its retracted position to pivot the advancing member against the action of said spring biasing to position the engagement means clear of the back runner to facilitate free sliding movement of said one of said jaws with respect to said support structure. In another aspect, the invention provides a support structure for a working device such as a clamping device on a work bench, comprising a central elongate support portion for the working device, and at least three support legs pivotably attached to the opposite ends of the elongate support and comprising at least two legs pivoted to the elongate support at the front of the support and at least one leg pivotably mounted at the rear end of the support, and collapsible bracing struts extending between said front legs and between said front leg bracing strut and said rear leg to releasably retain said legs in their supporting positions, said front legs being collapsible to lie along either side of the elongate support portion and said rear leg, lever arm and pedal being collapsible to lie along the length of the support portion to facilitate collapsing of the support structure into an easily transportable form. The front legs preferably have enlarged feet secured to their lower ends and to which the bracing struts are pivotably attached, said feet being positioned to enable the operator to stand on the feet to stabilise the support structure. In another aspect, the invention provides a locking device for an operating mechanism of a working device such as a clamping device, said operating mechanism including a reciprocatable rod and said locking device comprising a pivoted plate having an aperture through which said rod is free to pass when they are substantially perpendicular, said plate being spring biased to an angular position with respect to the rod in which the edges of the aperture in the plate grip the rod to prevent return movement of the rod when operative movement ceases, and lock releasing means comprising a pivoted lever having an abutment means positioned to engage the plate of said locking means to hold said plate in an orientation substantially perpendicular to the rod to allow the rod to slide freely through the aperture. One presently preferred form of the invention will now be described with reference to the accompanying drawings in which: Figure 1 is a partially sectional side elevation of a clamping device embodying the invention; Figure 2 is a fragmentary sectional elevation of the device showing the locking and advancing mechanisms of the device; Figure 3 is a perspective view from the front of the device of Figure 1 showing the collapsible supporting frame in greater detail, and Figure 4 is a perspective view of the device in the folded condition. Referring first to Figure 1, the device comprises a support structure 1 which incorporates an integral track 2 and a fixed jaw 3. The support structure 1 is supported by a foldable frame 4 (see Fig. 3 for greater detail). The support structure track 2 is adapted to receive a back runner 5 having an integral moving jaw 6. The back runner is adapted to freely travel back and forth along the track 2 and is also capable of complete removal and reversal thereby facilitating a very broad range of jaw openings. The vice operation of the jaws is in a positive direction with the back runner being engaged by an advancing member 8. The engagement of the back runner is effected by forward facing pawls 7 on the surface of the advancing member 8 which are specifically adapted through the bias of spring 15 to engage apertures 9 in the back runner 5. The apertures 9 in the back runner are adapted for bi-directional engagement to allow the runner to be reversed for extended jaw capacity, and in the present embodiment there are two rows of generally square apertures engaged by spaced pairs of pawls 7. The operation of the advancing member 8 is effected by an articulated connection to a foot operated lever means 10. The * lever has a front foot pedal 11 located at the operative end, and a rear pivot 12 to the support structure 1. The foot lever is terminated by a cranked lever 13 which is pivotally connected to the advancing member 8 by pivot 14 so as to effect an advancing action substantially parallel to the direction of travel of the back runner 5 in the track 2. The advancing member 8 is freely pivoted to the cranked lever 13 but is biased by a spring 15 which tilts the advancing member to effect engagement of the pawls to the apertures of the back runner. The action of the advancing member is further restrained by interaction with an abutment finger 16 (see Figure 2) which is positioned to partially withdraw the advancing member against the bias of the spring upon release of the foot lever (see Figure 3) . This action allows the pawls 7 to disengage the apertures 9 of back runner 5 and facilitates rapid advancing, retraction, removal or the reversal of the back runner 5 and moving jaw 6. Activation of the foot operated lever 10 causes the advancing member 8 to move forward, off the finger 16, and lift up by action of the spring 15 to engage the apertures 9 of the back runner 5. Further activation of the foot lever moves the advancing member 8 forward which causes the back runner 5 and moving jaw 6 to advance toward the fixed jaw 3. Once the full operating span is reached, the lever 10 is returned to its rest position by spring 30 (see Fig. 2) causing the advancing member to disengage the back runner (as previously described) and reverse back along the back runner, with the back runner remaining stationary due to friction, to a further point of engagement where another activating operation can further advance the moving jaw. This operation is repeated until the jaws engage the object to be secured. Referring now to Figure 2, the foot operated lever further incorporates a locking mechanism located near the front foot pedal 11. The locking mechanism is located near the pedal end of the foot lever 10 to minimise the forces required to lock the jaws at a given pressure. The locking mechanism comprises a rod 17 pivotally attached to the foot lever 10 and passing through an aperture 22 in a locking plate 18 positioned to effect a substantially tangential movement of the rod relative to the pivoting action of the foot lever 10. The locking plate comprises a pivoting, hardened steel locking plate 18 having an aperture 22 of greater diameter than the rod (Fig. 2), through which the rod 17 passes. The locking plate 18 is pivoted to the support structure 1 at 18a and is biased by a spring 22(a) to the locking position shown in broken outline in Fig. 2 such that movement of the rod 17 through the aperture 22 is normally limited to one direction only, said direction following the activation direction of the lever arm. As such, the locking plate provides a locking mechanism allowing the continuous and infinitely variable locking of the lever at any desired position. The mechanical advantage of the lever 10 and the continuous nature of the locking action ensure exquisitely fine control over the clamping pressure of the jaws whilst the very same mechanical advantage facilitates the availability of very high clamping pressure, if such pressure is required. Furthermore, the action of the advancing member 8 allows repeated advancement of the jaw 6 to operate in the manner of a press to perform pressing, bending or cropping off operations. The locking plate 18 is released by pivoting the locking plate 18 against the action of the biasing spring 22(a) to the position shown in solid outline in Fig. 2. A lock releasing plate 19 or lever is pivoted to support structure 1 and has an abutment 20 which engages the plate 18 to effect such release. The locking plate 18 is shaped to enable the abutment 20 to hold the plate 18 in the released position, as shown in solid outline in Fig. 2, to allow free travel of the rod and lever arm. The foldable frame 4 includes foldable support legs as detailed in Figures 3 and 4 where two front legs 23 are pivotally connected to the support structure 1 and straddle either side of the support structure 1. The two front legs 23 are fixed into the erect position by a bracing strut 25 comprising two struts joined at the centre by a locating housing 28. The rear leg 24 is pivoted from the rear of the support structure and is adapted to rigidly support the rear of the device being located in the erect position by a rear bracing strut 26 having a two part hinged construction joining the rear leg and the locating housing 28 of the front bracing strut 25. The rear bracing strut is positioned by forcibly opening the hinge to establish full strut length thereby placing the three legs under tension and rigidly establishing a very sturdy erect structure. The front legs 23 have foot plates 29 at their lower ends, to which the struts 25 are pivoted, to allow the frame 4 to be additionally stabilized by the user standing on one of the plates 29, or on the struts 25 and 26. In the foldable mode shown in Figure 4, the front legs fold back along the sides of the support structure and the rear leg folds up to lie along the length of the support structure and the lever 10 is folded about a pivot connection 31 as shown, to also lie along the length of the support structure to effect a compact and readily transportable unit. From the foregoing it can be seen that the instant invention provides a highly versatile clamping device incorporating a number of unique features. The device provides a very broad range of clamping capacities by virtue of the reversible jaws. The leverage mechanics offer a high mechanical advantage which supplements the power available bv operation to provide a device capable of very substantial clamping pressure or * pressing force. The locking mechanics allow a continuous and infinitely variable lock for the clamp which allows locking at any position. The result of this feature is that jaws may be quickly locked at any position and at any pressure. The collapsible legs offer the device a high degree of portability whilst having suitable bracing to ensure a very rigid structure upon erection. The claims form part of the disclosure of this specification.

Claims: WE CLAIM: 1. A clamping device comprising a support structure carrying two adjustably spaced apart jaws, lever means pivotedly connected to the support structure and operably engaging advancing means for moving at least one of the jaws relative to the other as the lever means is pivoted to apply a variable desired clamping force to an object between said jaws determined by the force applied to the lever, and locking means for restraining the two jaws in any desired position with said desired clamping force applied to the object. 2. A clamping device according to claim 1 further comprising lock releasing associated means with said locking means for deactivating the locking means whereby the lever means may be reciprocated to repeatedly actuate the advancing means to reduce the space between the jaws. 3. A clamping device according to claims 1 or 2 wherein one jaw is fixed relative to the support structure during the clamping operation, and the other jaw is a movable jaw mounted on the support structure for movement towards said fixed jaw during the clamping operation. 4. A clamping device according to any one of claims 1 to 3 wherein one jaw is removable from the support structure and reversible to extend the space between the jaws. 5. A clamping device according to any one of claims 1 to 4 wherein the locking means is operative to lock the lever means when the lever has reached the desired position and ceases pivotal movement in the advancing direction. 6. A clamping device according to claim 5 wherein the lever has an operative end to which pivoting forces are applied, said locking means operating at said operative end of the lever spaced a substantial distance from its pivotal connecition to the support structure. 7. A clamping device according to any one of claims 1 to 6 wherein said locking means comprises a plate pivoted to the support structure and having an aperture through which a rod connected to the lever moans is free to pass when they are in a substantially perpendicular orientation, said plate being normally spring biased to an angular position with respect to the rod so that the plate grips the rod when advancing movement of the lever ceases to prevent return movement of the lever and thereby to lock the advancing means and the jaws in any desired position. 8. A clamping device according to claim 7 when appended to claim 2, wherein the lock releasing means comprises a lever pivoted to the support structure and having an abutment means positioned to engage the plate of said locking means to hold said plate in an orientation substantially perpendicular to the rod to allow the rod to slide freely through the aperture. 9. A clamping device according to any one of claims 1 to 6 wherein the locking means comprises a clamp wedge, cam ratchet or friction grip mechanical means to restrain the lever means or the jaws in any position or at any desired clamping force. 10. A clamping device according to any one of claims 1 to 9 wherein a moving jaw is carried by an elongate back runner configured to engage a track formed in the supporting structure and having an array of spaced apertures, teeth or abutments formed along the length of the back runner, said advancing means including an advancing member having means to engage the apertures, teeth or abutments in said back runner, said advancing member being pivotally attached to the end of said lever means and being spring biased to cause arcuate movement of said advancing member towards the said back runner to cause engagement between said engagement means and said array of apertures, teeth or abutments when the lever means is pivoted in the operative direction, and an abutment finger carried by said support structure for engaging the rear end of said advancing member when the lever is in its rest position to pivot the advancing member against the action of said spring biasing to position the engagement means clear of the back runner to facilitate free sliding movement of said moving jaw with respect to said support structure. 11. A clamping device according to claim 10 wherein said engaging means comprises upstanding pawls formed to engage aperture(s) in said back runner and each of the pawls is formed with an undercut portion at their leading faces configured to engage a portion of the back runner surrounding the aperture engaged by each pawl to ensure positive engagement with said back runner. 12. A clamping device according to any one of claims 1 to 11 wherein the support structure comprises an elongate portion defining a track for slidably receiving said jaws(s), and at least three legs pivotably attached to the elongate portion and comprising at least two legs pivoted to the elongate portion at the front of the support portion and at least one leg pivotably mounted at the rear end of the support portion, and collapsible bracing struts extending between said front legs and between said front leg bracing strut and said rear leg to releasably retain said legs in their supporting positions, said front legs being collapsible to lie along either side of the elongate support and said rear leg, lever arm and pedal being collapsible to lie along the length of the support to facilitate collapsing of the support structure into an easily transportable or stowable form. 13. A clamping device according to claim 12 wherein the front legs have enlarged feet secured to their lower ends and to which the bracing struts are pivotably attached, said feet being positioned to enable the operator to stand on the feet to stabilise the support structure. 14. A clamping device comprising two adjustably spaced apart jaws carried by a support structure, pivoted lever means carrying advancing means for advancing at least one of said jaws relative to the other jaw, said advancing means including an advancing member having means to engage spaced apertures, teeth or abutments in an elongate back runner of one of said jaws, said advancing member being pivoted to the inner end of said lever means and being spring biased to cause arcuate movement of said advancing member towards the back runner to cause engagement between said engagement means and said spaced apertures, teeth or abutments when the lever means is pivoted in the operative direction, and an abutment finger carried by said support structure for engaging the rear end of said advancing member when the lever is in its retracted position to pivot the advancing member against the action of said spring biasing to position the engagement means clear of the back runner to facilitate free sliding movement of said one of said jaws with respect to said support structure. 15. A clamping device according to any preceding claims wherein said lever means is spring biased to return to its rest position. 16. A support structure for a working device such as a clamping device on a work bench, comprising a central elongate portion for the working device, and at least three support legs pivotably attached to the opposite ends of the elongate support and comprising at least two legs pivoted to the elongate support at the front of the support and at least one leg pivotably mounted at the rear end of the support, and collapsible bracing struts extending between said front legs and between said front leg bracing strut and said rear leg to releasably retain said legs in their supporting positions, said front legs being collapsible to lie along either side of the elongate portion and said rear leg, lever arm and pedal being collapsible to lie along the length of the support to facilitate collapsing of the support structure into an easily transportable form. 17. A support structure according to claim 16 wherein the front legs have enlarged feet secured to their lower ends and to which the bracing struts are pivotably attached, said feet being positioned to enable the operator to stand on the feet to stabilise the support structure. 18. A locking device for an operating mechanism of a working device such as a clamping device, said operating mechanism including a reciprocatable rod and said locking device comprising a pivoted plate having an aperture through which said rod is free to pass when they are substantially perpendicular, said plate being normally spring biased to an angular position with respect to the rod in which the edges of the aperture in the plate grip the rod to prevent return movement of the rod when operative movement ceases, and lock releasing means comprising a pivoted handle having an abutment means positioned to engage the plate of said locking means to hold said plate in an orientation substantially perpendicular to the rod to allow the rod to slide freely through the aperture. 19. A clamping device according to any one of claims 1 to 15 wherein said advancing means is configured to leave said at least one of said jaws free for adjustable movement with respect to said support structure to enable rapid advancement of the jaw(s) towards each other.

Inventors: ANGLIN MAURICE WILLIAM, COX ANDREW, ROBINSON RAYMOND LEONARD, ZACUPEK JACK, ANGLIN, MAURICE, WILLIAM, COX, ANDREW, ROBINSON, RAYMOND, LEONARD, ZACUPEK, JACK
Applicants: LEWIN GEORGE, LEWIN, GEORGE
Application year: 1992
Main classification: B25B1
IPC codes: B25B1, B25H1