This invention relates to holding and gripping devices, in particular vices, clamps, and similar deυices for the workshop and handyman.

Numerous devices of this general nature exist, but existing devices in general lack versatility and many are awkward to use.

There is a need for a clamp which can be set and locked ωith one hand, so that the user can use the other hand to position a workpiece or workpieces as they are being gripped by the clamp, either to hold a workpiece or ujorkpieces onto a bench or other surface, or to clamp uiorkpieces together.

The well known "Mole" (Trade Mark) wrench allows single-handed operation and locking but has very restricted use and cannot be used as a clamp or vice.

U. K. Patent 1450092 and U. S. Patent 3933346 of Carver disclose a clamping or gripping devic intended for one-handed operation, but the. described mechanism is awkward in construction and would consequently be difficult to use reliably, ωith only on nanri .

An object of this invention is to provide a clamp which can be positioned and clamped easily using one hand only .

The present invention provides a clamping device comprising opposite jaws which can be initially set relative to one another by relative, sliding of the jaws along a longitudinal support using the fingers and thumb of one hand acting on the respective jaws, the jaws being fixable relative to one another by jamming of at least one jaw on the said support, and a final clamping mechanism operable to move at least one jaw towards the other independently of the sliding motion relative to the support, the said mechanism being arranged to be operated by bring together the fingers and thumb used to effect the said sliding motion.

In one. aspect of the invention we provide a clamp comprising an elongate support; a first jaw mounted on the support and projecting substantially perpendicular to the support; a second j w facing the first jaw and mounted on the. support for sliding along the support towards and away from the first jaw; respective, grips associated with the jaws, such that the jaws can be moved towards and away from one another by the. fingers and thumb of a single hand of a user, means slidably mounting the second 3aw on the

support, sor arranged that the second jaw will friction- ally jam on the support when subjected to a load acting away from the first jaw and offset from the support; one of the said jaws being mounted for limited movement towards and away from the other of the said jaws independently of the said sliding of the. second jaw; and an operating mechanism for effecting the .said limited movement, comprising an operating member having a first position spaced from one. said grip, in which position the said one jaw is moved away from the other jaw, and a second position reached by movement of the operating member towards the said one grip and in which the said one jaw is moved towards the sa d other jaw.

Preferably the. said one jaw is the said first jaw, and the said one grip is that associated with the. second jaw. The other of the said grips may be a part of the operating member, or a second grip adjacent the operating member in the first position of the latter.

In a preferred embodiment, there is provided a clamp comprising an elongate support; a first jaw mounted on the support and projecting substantially perpendicular to the support; a second jaw facing the first jaw and mounted on the said support for sliding along the support towards and away from the first jaw, the first and second jaws being associated ωith respective grips such that the j ωs can

be moved towards and away from one. another by the fingers and thumb of a single hand of a user engaging said grips; the means slidably mounting the second jaw on the support being so arranged that the second jaw will frictionally jam on the support when subjected to a load offset from the support and acting away from the. first jaw; the. first jaw being mounted on the. support for limited movement towards and away from the second jaw; and an operating mechanism on the support for effecting the said limited movement of the first jaw, comprising an operating member having a first position adjacent the grip associated with the first jaw, in which position the. first jaw is moved away from the second jaw, and a second position in which the first jaw is moved towards the second jaw, the said second position being reached by movement of the. operating member from its said first position towards the. second j w.

Preferably, at least in its first position the. operating member lies along the support. The. operating member is preferably pivotable on the support and coupled to the first jaw through a cam or eccentric mechanism. -

The support preferably comprises a frame ωith two laterally spaced parallel guide limbs. The operating

member preferably comprises two parallel spaced levers interconnected at one end by a cross member and pivoted at their other ends on respective guide limbs

Another aspect of the present invention relates to a clamping device, comprising a pair of aws of extended area, laterally spaced parallel guides extending generally perpendicular to a first one of the jaws adjacent one side of the first jaw, the second jaw being slidable freely along the guide means towards and away from the first jaw, and a quick-action locking mechanism for locking the jaws relative to one another in a gripping position selected by the sliding of the second jaw

The laterally spaced parallel guides provide enhanced stability and positional accuracy for the second jaw

According to a feature of the clamp, respective hand grips are provided on the second jaw, and on the first jaw or guide structure, in such a way as to enable the user to move the second jaw and operate the locking mechanism easily with one hand, for example with the fingers and thumb respectively engaging the hand grips

The second jaω can slide freely on the guide means when not stressed, but grips the guide means when

stressed. for example, slight looseness may be provided between the guide means and the. second jaw so that when stressed, the second jaw tilts slightly and becomes frictionally wedged or jammed on a guide means. The locking mechanism operates to move ^' the jaws towards one. another, thereby applying stress to the second jaw to lock it, when in the gripping or holding position, for this purpose the. locking mechanism may act on either or both of the jaws, however in a preferred embodiment, the. locking mechanism acts to move. the. first jaw slightly towards the slidable second jaw thereby, in use, loading the. second jaw and causing it to lock itself on the. guide means .

In one convenient embodiment, the first jaw can slide, relative to the. guide means, and the locking mechanism comprises a lever-operated cam or eccentric arranged to move the first jaw towards the second jaw with enhanced force due. to the mechanical advantage, of the lever-cam/eccentric mechanism.

According to another feature, either or both of the. jaws, in particular the first jaw, is provided with a releasabl interlock for mounting operative attachments, such as additional gripping means (as a possible option only). for example, this may enable a vice to be mounted on the outer surface, of the first jaw, the first and second clamp jaws being clamped onto a workbench.

table edge or other surface so that the attached vice can b. used as a bench vice. It is proposed to provide a wide range, of operating attachments to be used in addition or substitute for either or both of the jaws of the device. for example:

A vice unit, attachable to the first j w enabling the combination to be used as a bench vice, secured by the clamp to the. bench.

An interconnector member enabling tools, grippers (vice units) and other components to be mounted on the basic clamp in various positions and orientations .

U-profile jaws as additional or substitute jaws or integrally for pipe clamping.

A mitre box unit and/or mitre, clamp unit attachable to the first jaw, enabling the mitre unit to be secured to a bench by the clamp.

Further attachments and accessories may include a dowel jig, pipe bending jaws, a drill stand, a drill guide, a tool caddy, a carrying handle.

It is envisaged therefore that the device may be marketed as a kit comprising the basic clamp and, for

example, interconnector members, vice, additional or substitute jaws, dowel jig, drill guide, etc.

The present invention also provides a gripping device, comprising an elongate frame having two parallel spaced guide rails as its side members; a first jaw mounted on an end of the. frame and projecting substantially perpendicular to the frame a second jaw facing the first jaw and mounted on a base in sliding engagement ωith the said frame for movement of the first jaw towards and away from the second jaw, in such a manner that the rails will frictionally jam relative, to the. second jaw when the. jaws are subjected to a load offset from the frame; a clamping mechanism for effecting limited movement of one. jaw towards the other independently of the said sliding movement; and in the base, a coupling port for receiving a coupling spigot, and retaining means for releasably retaining a coupling spigot received in the coupling port, whereby the. gripper can be mounted on a stationary object by means of such a spigot.

The present invention also provides in combination, a plurality of clamping devices each comprising relatively moveable jaws, and each provided with a respective coupling port for receiving a coupling spigot, and retaining means for releasably retaining a coupling spigot received in said port, whereby said

devices can be coupled together by means of sa d coupling spigots and retaining means.

BRIEF DESCRIPTION OF THE DRAWINGS.

An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 is a side view of a clamp embodying the invention,

Figure 2 is a rear view of the clamp of figure 1, partly cut away,

Figure 3 is a section on the line 3-3 in Figure 1, Figure 4 is a partial section on line 4-4 of figure

2 ,

Figure 5 is a plan view of the clamp, Figure 6 is a section on line 6-6 in Figure 1, Figure 7 is a section on line 7-7 in Figure 1, Figure 8 illustrates a system of work holders and inter-connecting means,

Figure 9 shows a vice or gripper in longitudinal section.

Figure 10 shows the vice or gripper in side view, Figure 11 is a plan view of the vice or gripper, Figure 12 shows the vice or gripper from below, n section on the line 12-12 of Figure 10,

Figure 13 is a cross section of the uice or gripper on the line. 13-13 in Figure 10,

Figure. 14 shows the. vice, or gripper in section on the line 14-14 in Figure 10.

In Figures 1 to 3 , the clamp is illustrated in its "released" condition.

The. illustrated clamp is designed to be. used with a- single user's hand, for clamping objects to one another and/or to a table, bench or the. like.

The illustrated device comprises a rigid generally rectangular U-shaped frame. 1 composed of a pair of laterally spaced parallel side plates, bars or rails 2, made for example of hardened steel, and optionally provided with apertures or recesses to reduce, weight, and a lower cross bar 4 of metal or plastics, integral with or fastened rigidly to the lower ends of the. rails. The upper ends of the rails are not connected to one another in the illustrated embodiment, but can be ■ so connected if necessary to provide rigidity.

It is to be understood that the terms "upper" ana "lower" and other relative terms used herein, refer to the orientation of the clamp shown in the drawings, which will be the. most common orientation in use, however the clamp can be placed in any desired orientation to suit the desired manner of use

The clamp has an upper jaw 5 and a lower jaw 6, each with a plane substantially rectangular gripping surface provided with a facing 3 of hard rubber or resilient plastics material, which may be ribbed or otherwise patterned to improve grip, The jaws can be made for example of light alloy castings for strength combined ωith lightness, or of any other suitable material, e.g.metal or high-duty plastics.

The upper jaw is an integral part of a generally L-shaped clamp head 8, forming one limb of the L as can be seen in Figure 1, The other limb of the L comprises a pair of spaced parallel flat limbs 10, which fit outside and lie closely adjacent and parallel to the upper end portions of the respective rails 2. The clamp head 8, in the region of the angle of the L-shape, has an internal configuration such that the clamp head is located on the upper ends of the rails but is not attached to these, and can slide bodily relative, to the rails in the longitudinal direction of the rails and of the depending side portions 10 of the clamp head, The amount of movement is, typically, about 1 to 3mm. In the illustrated embodiment, the. clamp head 8 has near each side an internal flat slot 9 in which is accommodated the. upper end of the respective rail 2. As shown m figure 4, the forward surface 11 of the upper end of the rail, and the abutting forward surface of the slot 9, are oblique Thus, when the upper j w 5

moves down relative to the. rails 2, the. contact between these, oblique surfaces on the rail and jaw tends to urge the upper jaw forwards, which provides positive location for the jaw against clamping loads and tends to tilt the upper jaw slightly downwards towards the lower, jaw, to enhance clamping of an object placed between them. The mechanism for effecting such movement will be described below.

The lower jaw 6 comprises a jaw plate 12 carried on a cantilever bracket or a pair of cantilever brackets 14 extending rearwardly and downwardly from the jaw plate between the rails 2 and having at its rear end a carriage. 16 which fits closely between the. inner surfaces of the corresponding rails, so that the lower jaw can slide along the rails, towards and away from the. upper jaw.

In the illustrated embodiment, the carriage 16 has at each side a pair of front and rear jam blocks 18 of hardened steel or other suitable, material, respectively engaging the front and rear edges of the respective, rail, and adjacent to these, jam block are anti-judder devices 17. The. surfaces of the jam blocks which make contact with the rail edges are slightly convex, and the jam blocks (the. forward blocks in the illustrated embodiment) may be mounted in the carriage so that they can "float" , to ensure, good engagement between these blocks and the rail edges.

Alternatively, the carriage may have, in each side, a channel-section groove fitting about the respective rail, the anti-judder devices being omitted and one or more jam blocks being mounted n the sides of the channel.

It will be seen that the line of action F of the forces arising when the clamp is used to clamp an object is generally parallel to _and offset forwards from the rails 2 on which the lower jaw 6 slides, and consequently clamping forces will tend to pivot the lower jaw (anticlockwise in Figure 1) relative to the rails 2, This will cause high local pressure between the front and rear jam blocks 18 of the carriage 16, and the front and rear edges of the rails, leading to high frictional forces between the respective mating surfaces so that, under load, the carriage will jam on the rails and cannot be moved along the rails away from the upper jaw. To enhance this frictional jamming action, the rails may have edges which are tapered, in cross section, the jam blocks having groves to engage the ra l edges, with similarly tapered cross sections; the rail edges and the groves in the m blocks may for example have included angles of about 20° to 30°, preferably about 25°

The anti-judder devices 17 ensure that when the lower aw is slid along the rails, t slides smoothly

without rocking or juddering. An anti-judder device is shown inset in figure 1. It comprises a spider of, for example, plastics material, with its arms fitting between the opposed flat surfaces of the rail and carriage, and with lateral pins 17a at the ends of its arms to fit against the edges of the. rail. This provides a light resilient centering action which prevents the. carriage, from binding on the. rail.

As already mentioned, the clamp head 8 with the upper jaw can move, along the. rails, by one or a few millimetres, towards and away from the lower jaw. To produce, and control this movement, the upper jaw is connected to the frame 1 through a mechanism of eccentrics controlled by a U-shaped handle. 20. This mechanism will now be. described.

In the. illustrated embodiment, each depending limb 10 of the clamp head is provided with an inwardly projecting pivot pin 22, these pins being coaxial and being rotatable in the respective arms 10. Each pivot pin has an outer region 28 with a cylindrical external surface, rotatably fitted in a circular aperture 24 in the lower end region of the arm 10. Adjacent this end region 28, the pin 22 has a flatted or otherwise non-circular intermediate region 26 which is a close f t in a correspondingly shaped aperture provided in the end region of a respective arm 34 of the U-shaped handle 20. It will be seen from figure 2, that the arms of the handle lie flat

against the internal surfaces of the arms 10 of the clamp head, between the. arms 10 and the. rails 2. The. arms of the handle, are angled, so that the. cross-piece. 36 of the handle. 20 lies against the. rear edges of the. rails, as can be seen in figure 3. A shoulder is formed between the regions 26, 28 of the. pivot pin, and the corresponding arm of the handle 20 is held against this shoulder and thereby on the pivot pin, by means of a "spire" retainer or other suitable retaining device 30.

At the. inner end of the. pivot pin 22, there is an eccentric 32 of reduced diameter with a cylindrical external surface. This is received in a corresponding cylindrical bore, provided in the internally adjacent rail .

Because the outer region 28 of the pivot pin 22 is eccentric relative to the inner region 32, if the handle 20 is rotated between the illustrated upper position, and a lower position (anticlockwise, in figure 3), the. eccentricity will cause the clamp head 8 to move bodily in the. longitudinal direction of the. rails.

The. direction in which the regions 28, 32 are eccentrically offset from one another is so placed relative to the handle 20 that, when the handle is in its raised position as shown, the clamp head is held in the uppermost position relative to the rails. If the

handle is now pivoted downwards (clockwise, in figure 1, anticlockwise in figure 3), the eccentric 32 will pull the rails bodily upwards into the clamp head, so that the jaws 5, 6 are moved towards one another. Typically, the eccentric throw and jaw movement are 1 to 3 millimeters with a handle movement of about 140° .

Alternative arrangements of the operating mechanism are. possible. In one. such alternative arrangement, each rail is placed between the associated clamp head arm 10 and side arm 34 of the handle, and each rail 2 is provided with an outwardly projecting pivot pin, these pins being coaxial. These, pins are integral with or firmly attached to the. respective rails.

Each arm of the clamp head has, in its lower end region, a circular aperture. An eccentric bush has a first end region with a cylindrical external surface rotatably fitted in the aperture, and a second end region of hexagonal or flatted profile, on its outer end. The. bush has a cylindrical bore fitted over the pin so that the bush can rotate on the. latter. The bore, is eccentric relative to the cylindrical portion of the bush, therefore, the aperture is held eccentrically relative to the pin.

Consequently, if the. bush is rotated on the. pin, ts eccentric region will cause, the clamp head to move bodily in the longitudinal direction of the. rails.

Each bush has its hexagonal region seated positively in a hexagonal aperture in a respective, side limb of the handle.

Each of the side, arms of the clamp head has a rebate or recess in the outer surface of its lower region, to accommodate the. respective side, lever arm of the handle when the latter is in the. raised position illustrated in figure. 1, so that the outer surface of the handle, lies substantially flush with that of the clamp head.

The eccentric region of the bush is so placed relative to the. handle, that, when the handle, is in its raised position, the eccentric bush holds the clamp head in the uppermost position of the head relative to the rails. If the. handle is pulled down, the eccentric will pull the clamp head bodily downwards along the. rails, so that the. upper jaw moves towards the. lower jaw.

To use the clamp, the user places the. article, or articles to be. gripped, between the jaws, and slides the lower jaw 6 towards the. upper jaw 5 to press against the. article, or articles under hand pressure, then rotates the handle 20 from the illustrated position downwards, so as to pull the upper j w towards the lower jaw. The initial pressure applied by the. user to the jaws in bringing them into engagement with the. article or

articles to be clamped, causes sufficient frictional engagement between the. pads 18 and the rails to lock the lower jaw frictionally on the. rails. The subsequent operation of the handle, to bring the jaws closer together greatly increases the clamping force, between the jaws and therefore the frictional jamming force between the lower jaw and the. rails. As long as the. handle remains in its lowered position, accidental release of the clamp is virtually impossible because of the strong frictional jamming of the lower jaw on the. rails

To release the clamp, the user lifts the. handle. 20 back to the position shown in Figure 1, thereby moving the jaws slightly away from one another and thereby relaxing the pressure on and frictional jamming of the lower jaw on the. rails; the jaws can then be slid apart.

A detent may be provided to hold the handle, in its lower position or the eccentric mechanism may be arranged so as to be over-centre when the handle is in the lowered, clamping position. However, in general friction will be. sufficient to prevent reverse rotation of the. eccentric from the. clamped position. A detent may be provided to hold the handle, in the "release" position illustrated in the drawings.

Between the. sides of carriage. 16, the lower aw s

provided with a pushed-in snap-fitted finger grip 38 comprising a box-like member of inj ction-moulded plastics, rubber, or other suitable material, open towards the rear and large enough to accommodate two or three fingers of a user's hand. The aperture 40 at the rear of this finger grip may have a lip to improve gripping, and its forward side may be. open or have holes for ventilation and to reduce the risk of foreign matter accummulating inside the finger grip. The finger grip may be mounted in such a way that it can pivot about a horizontal ^' axis perpendicular to the rails 2.

The clamp head 8 is also provided with a snap-fitted box-like rearwardly open finger grip 44, with the. lower lip 46 of its finger aperture 48 lying substantially level with and slightly forward of the cross-piece 36 of the handle 20 when the latter is in its raised "release" position, as best seen in Figure 1. The upper grip 44 is not pivoted but is fixed relative to the clamp head.

To use the clamp, the user places the thumb of one hand in one of the finger grips (usually the lower grip 38) and as many fingers of the same hand as is convenient, in the other finger grip. Holding the clamp in one hand in this manner, with the jaws apart and the handle 20 in its "release" position, the user fits the jaws over the article or articles to be clamped, for example a length of timber resting on a

workbench, or timbers to be joined together. By bringing the. thumb and fingers together, the. user moves the jaws towards one another until they lightly grip the. article or articles. Then the user, without releasing his hand from the. lower grip 38, withdraws the fingers (or thumb) from the upper grip 44 and in the. same motion pulls the handle 20 down to its clamping position, while continuing to exert, at least initially, finger pressure, on the lower grip 38 and on the. cross bar of the handle, to ensure that the. jaws remain in their gripping position until the carriage 16 has firmly jammed on the. rails as the upper jaw is pulled by the eccentric towards the. lower jaw.

The dimensions and positions of the. finger grips and handle 20 are ergonomically adapted to typical human hand dimensions, so that the described sequence of operation can be carried out easily by most users using one hand only throughout the. operations of placing the. clamp in position, sliding the jaws together, and operating the. clamping handle.

The above-mentioned pivoted mounting of the. lower hand grip 38 may be provided to accommodate, the. variation in finger and thumb angle, associated with different separations between the jaws, in that the lower grip can be angled upwards when the. aws are fully opened and the. hand relatively straight, and can be

angled downwards when the jaws are close together and the user's hand is almost closed This arrangement enables most users to operate the clamp with a jaw separation up to 11 - 13cm The lower wall of the upper grip may be angled, to facilitate gripping and holding by the user

The eccentric pivot pins 22 have end covers 50, which are made sufficiently large and suitably shaped to be used as gripping means by the user

Means may be provided to ensure that the handle 20, when in its fully lowered clamping position, does not interfere unduly with the carriage 16 and the interposed lower finger grip 38, for example a stop may be provided to limit the pivoting of the handle to an end position clear of the carriages 16 and finger grip 38

From the foregoing description of the way in which the clamp operates, it will be understood that the final clamping action using the eccentric mechanism presupposes that the aws w ll be capable of limited approach movement after having been brought nto initial engagement with the articles to be clamped It is for this reason as well as to protect clamped articles, that the jaws have facings of hard rubber or resilient plastics material, capable of being deformed to accommodate the final approach movement of the aως or operation of the handle 20

Figure 7 shows a tolerance-equalisation bar 63 located inside, the carriage 16, with spigots at its ends on which respective, forward jam blocks 18 are. located, so as to ensure good conditions of engagement despite manufacturing tolerances .

The bar 63 can pivot about its mid-point in the. carriage, and has at each end a cylindrical pin on which the. jam blocks can swivel individually. This allows bad transfer from one black to the other, to ensur equal jamming conditions at both rails.

In addition to serving as a clamp, the clamp may also serve as a mount for other devices, for example, a bench vice or gripper. To this end, the top jaw 5 is provided with means, accessible at its upper or outer surface 52, for releasably coupling such additional devices. Thus, the. illustrated clamp has in its' top jaw an upwardly open cylindrical port 54, and within the. clamp head is a releasable retaining mechanism of any suitable kind, operated by a pivotable lever 56 on the. clamp head. Thus, a coupling spigot can b inserted in the port 54 and held therein by the retaining mechanism operated by the. le-ver 56. A suitable, coupling spigot may be. provided on the. ancillary device, to be mounted on the clamp top jaw, or the. ancillary device may itself be provided ωith a corresponding port and retaining

mechanism, so that a separate, spigot member inserted in both of the ports, in the clamp top jaw and in the ancillary device, can fasten the clamp and ancillary device together. Ancillary devices which can be used with the clamp in this way may include, for example, a vice, a mitre block, saw blocks, a corner clamp, and various other devices for supporting workpieces, and/or tools .

One form of retaining or interlock mechanism is shown in figure. 6, which is a horizontal section through the upper jaw. This jaw is hollow and contains a clamping saddle 51 of which an intermediate region 53 is a circular arc corresponding in radius and position to a portion of the periphery of the port 54, and immediately below the. latter in the hollow space 55 within the. clamp head. One. end of the. saddle 51 is held between the head of an adjustable screw 55 inside the. clamp head, and a compression spring 57, so that the concave, intermediate region of the saddle is urged by the spring to a normal position in which it does not impede, insertion of a coupling spigot into the port 54. At the other end of the saddle is an anvil 58 which is pressed by the spring 57 against an eccentric or cam surface 59 at the pivoted end of the lever 56.

The lever 56 is pivoted on a pm 60 mounted n the rear region of the upper jaw or clamp head The lever

engages the pivot pin by means of a slot 61 extending in the longitudinal direction of the lever, and the. leve has a shoulder 62 arranged to engage a flat internal surface of the clamp head. The. arrangement is such that when the lever is pivoted to lie flush with the rear of the clamp head (which is slotted or recessed to accommodate, the. lever), the cam 59 presses against the anvil 58 and thereby pushes the saddle forwards towards the axis of the port 54, so as to clamp against the opposite, side of the port, with a coupling or interlock spigot inserted into the port. The upper jaw may have a fixed saddle below the coupling port and facing the moveable saddle. 51. If the lever 56 is pivoted out of the. clamp head (anticlockwise in figure. 6), the cam 59 allows the saddle 51 to relax away from the. port axis, under the. action of the. spring 57, thereby releasing any inserted spigot, or allowing a spigot to be inserted in the. port 54.

In its clockwise, clamping poisition, the. lever 56 can be pushed longitudinally, so that its shoulder 62 comes into contact with the adjacent flat internal surface of the clamp head 8, by which means, the. lever 56 is locked in its clamping position. To release the lever and enable it to be pivoted to the. unclamping position, the. lever must first be pulled away from the pivot pin 60". In its clamping position, the lever 56 is fully flushed with or recessed into the clamp head, s:■ that it cannot be released accidentall .

Alternative forms of coupling interlock mechanism are possible For example, a pivoted saddle may be placed on the opposite side of the coupling port, relative to the operating lever, and may be operated by a pull rod which m tern is coupled to the lever through an eccentric bush so that pivoting the lever tightens or relaxes the pull rod and hence the clamping saddle

In another possible interlock clamping mechanism, a C-clamp has a circular internal profile coaxial with and of substantially the same diameter as the coupling port A rod extends through the jaws or saddles of the C-clamp, being positively secured to one of the saddles at one end and being coupled at the other end to a cam which when rotated by the operating handle or lever acts on the adjacent saddle, so as to force the saddles together

Preferably, the interlock clamp mechanism includes an adjusting screw (which may be the screw 55 n figure 6) for adjusting the normal saddle opening and clamping pressure

The upper finger grip 44 may project forwards of the rails The finger grips must have sufficient depth for the fingers and thumb to_ gr p them securely, and n addition, th s forward projection of the upper grip would ensure tnat articles being clamped cannot be placed directly against rails It ωill oe unαe^stooc

that if an article were so placed, close to the. rails, the off-centre, force acting on the lower jaω to produce its frictional jamming on the. rails would be reduced. It is therefore desirabl that articles being clamped should not be too close to ^' the rails.

Numerous changes and modifications can be made, within the. scope of the invention.

For example, the upper finger grip may be. pivotable. in addition to, or instead of, the lower finger grip being pivotable.

The. described eccentric mechanism can be replaced by any other suitable eccentric or cam arrangement for causing the upper jaω to move towards the. loωer jaw.

The clamping movement of the upper jaω may be a pivoting movement instead of the described bodily sliding movement. For example, the upper jaω may be mounted betωeen forωardly projecting ends of respective cranked side levers, each pivoted at an intermediate point, and each coupled at a loωer end to a cam or eccentric mechanism operated by a handle similar to the handle. -20, arranged to pivot the side levers and thereby loωer the. upper jaω on operation of the handle.

One. or both of the jaws may be detachable and replaceable by special-purpose jaws, for example pipe grippers. Alternatively, a special-purpose aw may be fitted under the upper jaw, by means of the coupling port 54 and associated retaining mechanism, if the. port is made accessible from the underside of the. upper aw.

The upper jaw may be provided with detent recesses or the like around the. coupling port, to engage a corresponding detent for example a spring-loaded ball on the. attached ancillary device, to provide, location of the latter at specified angular orientations.

To increase, the. available range, of jaw openings, the lower jaw may be separable from its carriage, and capable of being mounted on it at different relative positions .

The illustrated finger and thumb grips have, roughly triangular openings so that each is capable of accommodating several ■fingers . Alternatively, either or both of the grips may have, multiple, openings side, by side to receive individual fingers. The finger and thumb holes may have, flexible rubber or plastics lips, to grip the. inserted thumb and fingers and reduce the. risk of the. clamp falling from the hand of the. user.

The upper grip can be omitted, the cross-piece of the handle instead serving as a finger or thumb grip by means of which the user can hold the clamp, in its open condition, with a single hand and can slide the jaws towards one another prior to pivoting the handle for the final clamping action as already described. It is however greatly preferred to provide a separate fixed finger grip associated with the. upper jaw, as this enhances ease and safety of use.

As already mentioned, the clamp is provided with a coupling port on its top jaw, for mounting other devices on a bench. Figure 8 illustrates a system of workpiece holding devices. This comprises the clamp 100; a vice or gripper 102; a bench mount 106; an interface member 108; and interconnecting members 110;

The vice 102 has in its base. 114 a coupling port and retaining mechanism which may be similar to that in the head of the. clamp. Each interconnector member 110 has two oppositely directed coaxial spigots 98 of metal tubing, with an intermediate metal or plastics ring 96 to act as a spacer and for ease of handling. In use, one spigot can be. inserted in the. coupling port of the. clamp, the latter being clamped on the. bench edge, and the opposite spigot in the. coupling port of a vice base, the respective retaining mechanisms in the clamp head and vice base then being operated to fasten the coupling

member in the clamp head, and the vice on the coupling member, thereby fixing the vice to the bench on which the clamp is clamped.

The bench mount 106 comprises a base 116 and an upstanding spigot 110. The base, can be. screwed onto a bench top, and the vice, can then be. coupled onto the spigot 110.

For interconnecting components at different angles, the interconnecting member 108 comprises a metal or plastics body generally in the. form of a right angled triangle, with two perpendicular coupling spigots 110.

The gripper has a construction partly similar to that of the clamp, in that it operates by a combination of a jamming action for coarse selection of the distance between the jaws, and a separate final clamping action. A static jaw 126 is integral with the gripper base. 114, and faces a moving jaw 122. The. moving j w 122 is at one end of, and perpendicular to, a sliding frame. 128 which consists of a pair of flat side, rails 130 parallel to each other, a moving jaw head 132 fastened to and bridging the. rails at one end, made of metal or suitable plastics, and a metal or plastics cross-bar 134 connected to and extending between the rails at their opposite end .

The static jaw 126 engages the rails through a jamming mechanism generally similar to that of the clamp. The. base 114 is connected to the jaω 126 by an intermediate region which fits between the rails and is provided, on each of its opposite, sides, with upper and lower jam blocks 136 in contact with the upper and lower edges of the. rails and with an anti-judder device. 138. It will be seen that if the moving jaw 122 is moved towards the static jaw 126 to generate a clamping pressur between the jaws, this will tend to tilt the rails anticlockwise, in figures 9 and 10, thereby increasing friction against the jam blocks 136 and frictionally jamming the jaws in position relative to each other. This jamming action will tend to arise naturally because the weight of the moving jaw will in itself produce sufficient friction. The moving jaw is therefore essentially self-locking in whatever position it is set to by the user.

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Final clamping pressure and enhanced jamming of the rails in the static jaw are produced by a screw-operated clamping plate 140 housed in the moving jaw and moveable towards and away from the static jaw. To produce, this movement, the. clamping plate 140, which has a skirt accommodated in the hollow body of the moving jaw 122, is loosely coupled to the. forward end of a pin 142, which has an external screw thread on its shank, threaded into a tapped bush 144 integral ωith the moving

j w 122. The opposite end of the s rew-threaded pin is fastened into an operating knob 146 comprising, for example, three large ribs for easy manipulation

The clamping plate 140, and the static j w 126, are provided with replaceable rubber jaw pads 148

The gripper base 114 contains an interlock clamp mechanism. In the illustrated embodiment, the interlock port 150 is defined by a fixed semi-circular saddle 152 in the gripper base and an opposed semi-circular moving saddle 154, In a manner analogous to that of the interlock mechanism in the clamp upper jaw, one end of the moving saddle 154 is retained by an adjustable screw 156 seated in the fixed saddle, and a compression spring 158 which urges the moving saddle away from the axis of the port 150. At the other end of the moving saddle is an anvil 160. This end of the. moving saddle is also urged away from the fixed saddle, by a compression spring 162 seated in the fixed saddle.

The spring 162 presses the anvil 160 against an eccentric or cam 164 on one end of an operating lever 166, this end being pivoted on a pin 168 in the base 114.

As n the case of the clamp interlock mechanism, when the lever 166 is pivoted out from the ipp r base

114, the cam 164 allows the. anvil 160 to relax so that the saddle. 154 moves away from the. axis of the port 150. When the handle 166 is pivoted in to lie flush with the base. 114, the cam 164 pushes the anvil 160 towards the. fixed saddle, so that a spigot inserted between the fixed and moveable saddles will be clamped