GB2102327A

GB2102327A - Clamping mechanism attachments

Info

Publication number: GB2102327A
Application number: GB08217543A
Authority: GB
Inventors: Ronald Price Hickman; Brian Anthony Luff; Robert Alan Lunt; Derek John Charles Bernard
Original assignee: Tekron Licensing BV
Current assignee: Tekron Licensing BV
Priority date: 1981-06-19
Filing date: 1982-06-17
Publication date: 1983-02-02
Also published as: IT1189299B; FR2507945A1; DE3222812A1; IT8248672A0

Abstract

A clamping mechanism attachment, for use with a workbench incorporating a pair of elongate moveable vice members, comprises a pair of similar opposed jaw carriers (602) each having a locating spigot (603) for location in an aperture in one of the vice members and each carrying a pivoted jaw (608) whose pivot (609) is slidable along a slot (612) for erecting the jaw in any one of a series of vertical positions on the carrier (602) determined by notches (615). The jaw carriers (602) are slidable along a common reaction bar (605) for moving the jaws (608) towards and away from one another by operation of the vice handles and are restrained from tilting about horizontal axes perpendicular to the direction of sliding. A plain jaw face (623) is mounted on one of the jaws (608), and a workpiece support finger (670) is pivotally mounted on the other of the jaws (608). <IMAGE>

Description

SPECIFICATION Clamping mechanism attachments This invention relates to attachments for clamping mechanisms which may either comprise a vice or a workbench having a structure in the form of a vice. Thus the invention is particularly applicable to attachments for a clamping mechanism incorporating a structure in the form of a vice formed by a pair of vice members having vice operating means for drawing them towards and away from one another, and a number of upwardly extending holes or recesses opening through the top surface of each vice member.

Such clamping mechanism is defined as a clamping mechanism of the type specified.

The invention is particularly, but not exclusively, applicable to a type of workbench which has been very successfully marketed under the trade mark WORKMATE. This comprises a portable workbench having a top structure formed by a pair of elongate rectangular beams, one beam being of a fixed nature and the other beam being movable towards and away from the fixed beam by a pair of operating screws. Workbenches of this type are protected by the following British patents:- 1,267,032; 1,267,033; 1,267,034; 1,267,035; 1,405,892; 1,405,893; 1,405,894; 1,405,895 and 1,405,896.

Of the above patents, patent 1,237,032 relates specifically to a structure in which the vice members of the workbench can be set at an angle to one another by independent operation of the vice screws. A further patent, 1,422,521, is directed to the provision of spaced bores in the vice members which can receive plug-in abutments for use in clamping workpieces or irregular shapes placed on the top of the workbench. Figure 9 of that patent illustrates a two part metal workers vice capable of attachment to the workbench. Each part includes a casting, the forward face of which is formed with intersecting V-shaped grooves. Just to the rear of the face of the casting there is a steel pin which can be located in one of the holes in the beams of the vice.A further peg is positioned for engagement in a further hole in the beam or beams of the vice. Experiment with such constructions has indicated that problems arise due to the fact that the clamping faces within which a workpiece is received are spaced well above both the lines of action of the vice screws of the workbench. As a result there is a tendency for the reaction caused by clamping of a workpiece to pivot the parts of the metal workers vice apart about horizontal axes and reduce the clamping efficiency.This action would be accentuated even further if attempts were made to increase the height of the abutment faces of the two halves of the metal workers vice and in fact the application of any considerable load will tend to rotate the spigots or pegs located in the holes also about horizontal axes which can tend to damage the holes in the beams of the workbench, and in extreme circumstances tear away the materials of the beams of the workbench where the holes are positioned closely adjacent an edge thereof.

As a consequence it has not previously been possible to provide a satisfactory arrangement for clamping large workpieces above the plane of the workbench due to the offset loads which are incurred.

According to one aspect of the present invention an attachment for a clamping mechanism of the type specified comprises a pair of interconnected structures each having an abutment for clamping against a workpiece and a base portion which has at least one downwardly extending spigot to be received in one of the upwardly extending holes or recesses of the clamping mechanism, the structures being interconnected so as to permit a sliding movement between them to vary the gap between the abutments whilst restraining the abutments from tilting movements about substantially horizontal axes generally perpendicular to the direction of sliding movement during clamping of a workpiece between them whilst mounted on the clamping mechanism and during operation of the vice operating means.

The manner in which the restraint from tilting movement is obtained can vary but one particular embodiment incorporates pin and slot connections extending between interconnecting portions of each structure. Alternatively other forms of guidance may be provided to prevent the tilting of the abutments. For example the interconnecting portions may be formed by telescopically cooperating tubes, the reactions tending to cause the abutments to rotate being accommodated by engagement of the faces of the tubes.

In another embodiment each structure has a horizontally extending interconnecting portion integral with, and extending from its respective base portion towards the other base portion, and each base portion having a downwardly facing thrust surface engaging an upwardly facing thrust surface of the other interconnecting portion.

In a further embodiment each base portion has a pair of vertically and horizontally spaced thrust members, the upper thrust member facing downwardly and the lower thrust member facing upwardly, and a separate interconnecting bar arranged to extend horizontally between the base portions and to lie between the pair of thrust members at each end.

Preferably, the attachment includes a pair of jaw carriers each having a jaw providing a different one of the abutments and a base portion which has at least one of the downwardly extending spigots, at least one of the jaws being capable of being positioned on its carrier in a selected one of a number of defined positions.

According to another aspect of the present invention an attachment for a workbench of the type incorporating a top structure in the form of a vice formed by a pair of elongate vice members having vice operating means for drawing them towards and away from one another and a number of upwardly extending holes or recesses opening through the top surface of each vice member comprises a pair of structures affording abutments having upwardly extending tooth portions facing each other, a base portion on each structure and provided with at least one downwardly extending spigot to be received in one of the upwardly extending holes or recesses of the workbench, and interconnecting portions one on each structure which overlap one another and which include a horizontal slot in each interconnecting portion which is engaged by a pin secured to the other interconnecting portion to permit a sliding movement between the structures to vary the gap between the abutments and to restrain the abutments from tilting movements about horizontal axes during clamping of a workpiece between them whilst mounted on the workbench and during operation of the vice operating means.

According to another aspect of the present invention an attachment comprises a pair of structures each of which includes a horizontal base having at one end a downwardly extending spigot to be received in one of the upwardly extending holes or recesses of the workbench and at the other end an upwardly extending abutment for clamping against a workpiece, each bar having a horizontal elongate slot in which a pin carried by the other bar is received, thereby to maintain the two bars in parallel sliding relationship and to restrain the abutments from tilting movements about horizontal axes during clamping of the workpiece between them whilst the attachment is mounted on the workbench and during operation of the vice operating means.

According to a further aspect of the present invention, an attachment for a clamping mechanism as specified above comprises a pair of jaw carriers each having a jaw for clamping against a workpiece and a base portion which has at least one downwardly extending spigot to be received in one of the upwardly extending holes or recesses of the clamping mechanism, the carriers being interconnected so as to permit a sliding movement between them to vary the gap between the jaws whilst restraining the jaws from tilting movements away from each other about horizontal axes perpendicular to the width of the gap during clamping of a workpiece between them whilst mounted on the clamping mechanism and during operation of the vice operating means, at least one of the jaws being capable of being positioned on its carrier in a selected one of a number of defined positions.

The arrangement enables the said one jaw to be coarsely set at the required spacing from the other jaw merely by moving it in relation to its carrier to one of the defined positions, and thereafter clamping movement of the jaws can be effected by operating the vice of the type of workbench described above.

The arrangement enables horizontal clamping loads to be applied at a substantial distance above the workbench surface without giving rise to twisting movements about axes parallel with the length of the vice member faces. The present invention also has that advantage particularly with bulky and very wide loads to be clamped between the jaws, and that effect is increased if the jaw carriers are interconnected by a beam extending horizontally in the direction of the width of the gap between the jaws with each jaw carrier being incapable of turning in relation to the beam about a horizontal axis transverse to the width of the gap. For example, each jaw carrier may be a fairly close sliding fit along the beam.

That means that the vice members can be used at their extreme separated positions with each jaw carrier spigoted in one of the vice members, with the jaws at their most wide apart defined positions on their carriers and with the beam being sufficiently long to extend between the jaw carriers.

Various detachable jaw faces may be mounted on the jaws for gripping a workpiece positioned between the jaws.

According to a further aspect of the present invention, an attachment for a clamping mechanism incorporating a structure in the form of a vice formed by a pair of vice members having vice operating means for drawing them towards and away from one another in a generally horizontal plane, the vice members having opposing clamping faces of restricted depth, and a number of upwardly extending holes or recesses opening through the top surface of each vice member, the attachment having a pair of abutments for clamping against a workpiece, which abutments afford opposed clamping faces of greater depth than those of the vice members, the attachment comprises a pair of interconnected structures each having one of the abutments and a base portion which has at least one downwardly extending spigot to be received in one of the upwardly extending holes or recesses of the clamping mechanism, the structures being interconnected so as to permit a sliding movement between them to vary the gap between the abutments whilst restraining the abutments from tilting movements about substantially horizontal axes generally perpendicular to the direction of sliding movement during clamping of a workpiece between them whilst mounted on the clamping mechanism and during operation of the vice operating means.

According to another aspect of the present invention, an attachment for a clamping mechanism incorporating a structure in the form of a vice formed by a pair of vice members having vice operating means for drawing them towards and away from one another in a generally horizontal plane, the vice members having opposing clamping faces and the structure being such that a workpiece extending along the complete length of the vice members and being clamped by the opposing clamping faces is restricted in the depth to which it may extend below the vice members, and a number of upwardly extending holes or recesses opening through the top surface of each vice member, the attachment having a pair of abutments for clamping against a workpiece, which abutments, when mounted on the clamping mechanism, afford opposed clamping faces at a greater height than those of the vice members, to allow a workpiece being clamped by the opposing clamping faces of the abutments to extend to a greater depth below the attachment clamping faces than the depth to which the workpiece could extend below the clamping faces of the clamping mechanism when clamped between the pair of vice members, the attachment comprises a pair of interconnected structures each having one of the abutments and a base portion which has at least one downwardly extending spigot to be received in one of the upwardly extending holes or recesses of the clamping mechanism, the structures being interconnected so as to permit a sliding movement between them to vary the gap between the abutments whilst restraining the abutments from tilting movements about substantially horizontal axes generally perpendicular to the direction of sliding movement during clamping of a workpiece between them whilst mounted on the clamping mechanism and during operation of the vice operating means.

According to yet another embodiment a workbench comprises a pair of elongate vice members, one of the vice members being arranged for movement towards and away from the other vice member either in a parallel manner or in a manner which enables one end of the movable vice member to be be drawn nearer to the other vice member, each vice member having a number of upwardly extending holes or recesses opening through its top surface, and an attachment carried by the vice members comprising a pair of interconnected structures each having an abutment for clamping against a workpiece at a level above the surface of the vice members, and a base portion which has at least one downwardly extending spigot received in one of the upwardly extending holes or recesses of the vice members, one spigot being received in a hole or recess in one vice member and the other spigot being received in a hole or recess of the other vice member, the two structures being interconnected so as to permit a sliding movement between them to vary the gap between the abutments whilst restraining the abutments from tilting movements about horizontal axes during clamping of a workpiece between them and during operation of vice operating means.

According to another aspect of the present invention, a workbench having a top structure in the form of a vice comprises a pair of elongate vice members, one of the vice members being arranged for movement towards and away from the other vice member either in a parallel manner or in a manner which enables one end of the movable vice member to be drawn nearer to the other vice member, each vice member having a number of upwardly extending holes or recesses opening through its top surface, and an attachment according to the present invention in which the two jaw carriers or interconnected structures are coupled to the respective vice members by virtue of the downwardly extending spigots being in the upwardly extending holes or recesses in the respective vice members.

According to a further aspect of the present invention in an attachment for a clamping mechanism of the type specified, the attachment includes a pair of interacting structures, each of the structures comprising a substantially L-shaped member including a generally horizontally extending portion and an upwardly extending portion affording an abutment for clamping against a workpiece, each of the structures having a base portion including at least one downwardly depending spigot, the base portion being in the region where the generally horizontal and the upwardly extending members meet with one another and each of the spigots is to be received in a different one of said upwardly extending holes or recesses of said clamping mechanism, each of the base portions having a downwardly facing thrust surface, and each of the generally horizontally extending members having an upwardly facing thrust surface, each of the horizontally extending members being arranged to be co-extensive with one another whereby an upwardly facing thrust surface of each of the generally horizontally extending members interacts with the downwardly facing thrust surface of the other structure so as to permit a sliding movement between the structures to vary the gap between the abutments whilst restraining the abutments from tilting movements about substantially horizontal axes generally perpendicular to the direction of sliding movement during clamping of a workpiece between them whilst mounted on the clamping mechanism and during operation of the vice operating means.

According to a further aspect of the present invention in an attachment for a clamping mechanism of the type specified, the attachment includes a pair of structures and a bar extending between the structures, each of the structures including an upwardly extending member affording an abutment and a base portion including a downwardly extending spigot, each of which spigots is to be received in a different one of the upwardly extending holes or recesses of the clamping mechanism, each of the structures including an upwardly facing and a downwardly facing thrust surface and the bar including a downwardly facing and an upwardly facing thrust surface in the region of both structures, the downwardly facing thrust surfaces on each of the structures being spaced further from each other than the upwardly facing thrust surfaces, whereby the upwardly facing and downwardly facing thrust surfaces at either end of the bar act respectively against the downwardly facing and upwardly facing thrust surfaces of each of the structures so as to permit a sliding movement between the structures to vary the gap between said abutments whilst restraining the abutments from tilting movements about substantially horizontal axes generally perpendicular to the direction of sliding movement during clamping of a workpiece between them whilst mounted on the clamping mechanism and during operation of the vice operating means.

The invention may be carried into practice in a number of ways but several specific embodiments will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 illustrates a pair of attachments according to the invention mounted on a workbench and being used to clamp a log which is shown diagrammatically; Figure 2 is a perspective view of an alternative form of attachment; Figure 3 is a part-sectional side elevation of the embodiment of Figure 2; Figure 4 is a perspective view of a further embodiment; Figure 5 is a perspective view of a further embodiment; Figure 6 is a perspective view of a further embodiment; Figure 7 is a perspective view of a further embodiment; Figure 8 is an end elevation of an embodiment in which the workpiece is supported by a strap;; Figure 9 is a view similar to Figure 8 but in which a workpiece is held down by a strap; Figure 10 is a perspective view of yet another embodiment; Figure 11 is a perspective view of a further embodiment; and Figures 11 A and 11 B show two different forms of jaw face for use with the attachment of Figure 11 instead of the jaw face there shown.

Figure 1 of the drawings shows the top structure of a workbench which includes a pair of elongate vice members 10 and 12, the former of which is secured in an immovable manner to a pair of transverse supports 14 and 1 6. The transverse supports 1 4 and 1 6 have horizontal slide surfaces 18 on which the vice member 12 is arranged to rest during a sliding movement towards and away from the fixed vice member 10.

This movement of the vice member 12 is caused by actuation of one or both of a pair of vice handles 20 each of which is mounted on the forward end of a horizontally extending screw threaded rod 22 which is journalled to the front end of the appropriate transverse support 14 or 16. Each screw carries a nut 24 which is connected to the underside of the movable vice member 12 by a vertically extending pivot. This allows the independent operation of the two vice handles 20 in the manner described in British Patent 1,267,032. Thus the vice member 12 can be moved in such a way that its vice face 30 remains parallel to the corresponding face of the fixed vice member 10, i.e. by simultaneous and equal speed rotation of the handles 20.

Alternatively by operation of one handle alone, or the handles at different speeds, the vice member 12 can be set at an angle to the vice member 10.

Each vice member 10 and 12 has in it a number of vertically extending bores 32. The parts so far described represent a workbench of weli known type sold under the trade mark WORKMATE.

In the drawings and shown mounted on the workbench are a pair of attachments according to the present invention. Each comprises a jaw structure having two upwardly extending gripping portions 40 each provided with teeth 42 on its inwardly facing surface. Each gripping portion 40 is integral with an interconnecting portion 44, the two interconnecting portions being in face-to-face relationship and each having a circular base 46.

Each base 46 has a downwardly extending spigot 28. These spigots extend through (as loose fits) the bores 32 in the vice members 10 and 12.

Each of the interconnecting portions 44 has a horizontal elongate slot 50 and located in each slot is a shank of a bolt 52 extending laterally from the lower end of the upwardly extending gripping portion 40 of the other jaw. Each bolt 52 has a head which is larger than the width of the slot with which it is associated and the bolt is so tightened that the two jaw structures are capable of free sliding movement to vary the distance between their teeth 42. In other words the jaws have between them a pair of pin and slot connections.

With the arrangement described and as shown in Figure 1 a log diametrically indicated at 60 can be located between the opposed teeth of each jaw if necessary after widening of the gap between the teeth by moving the rear vice member 12 rearwardly. It will be appreciated that movement of the vice member 12 is transmitted to the rear gripping portion 40 of each jaw via the spigot 28 associated with that gripping portion. When a log is suitably located between the jaws, the handles can then be operated together or independently to draw the rear gripping portions forwardly to apply a gripping load between the teeth on the two jaws.It will be appreciated that the gripping action causes a reaction on the gripping portions 40 which tends to rotate them apart, i.e. the righthand gripping portion 40 in each case will tend to rotate clockwise as viewed in Figure 1 and the left-hand gripping portion 40 will tend to rotate anti-clockwise. These tendencies to rotate however are completely balanced by the provision of the pin and slot connections since the left-hand pin and slot connection of each jaw will resist clockwise rotation of the right-hand gripping portion 40 and similarly the right-hand pin and slot connection will resist anti-clockwise rotation of the left-hand gripping portion 40. As a consequence the spigots 28 remain upright and in full contact with the bore of the appropriate vice member in which they are received and there is thus no tendency, due to the offset loading effected by the screws, for the spigots to damage the material of the workbench.

It is to be noted that the interconnecting portions 44 have oppositely inclined upper surface. When the vice members are separated by movement of the rear vice member 12 rearwardly, the separating movement causes the upper surfaces of the interconnecting portions to bear against the underside of the log 60 and bias it upwards out of engagement with the teeth 42 of the gripping portions 40.

The design of the embodiment of Figure 1 provides a very sturdy construction able to withstand the considerable forces which are incurred due to the clamping at a substantial distance spaced from the line of action of the screws 22.

A further aspect of the first embodiment which is to be particularly noted is that the two halves of each jaw are identical so that tooling is an extremely simple operation Reference will now be made to a second embodiment of Figures 2 and 3 which embodies similar principles but which has certain further features.

Thus a jaw is formed between two vertical pillars 62 and 64 which as will be described can be shifted towards and away from one another.

Each pillar is of generally square cross-section and is formed from tube and has five spaced circuiar holes 66 in the opposed faces 68 and 70 respectively and in the outwardly facing faces 72 and 74 respectively.

The pillar 62 is integrally connected to a horizontal rectangular tube 76 having an elongate slot 78 in each of its side faces. Immediately below the pillar 62 is a single spigot 80 for engagement freely in a bore 32 of a workbench such as that shown in Figure 1.

The second pillar 64 is mounted on a saddle 82 having side flanges 84 each provided with a T-shaped slot 86 for cooperation with laterally extending pins 88 extending from the sides of a further rectangular tube 90. Extending from side to side of the tube 90 are a pair of cylindrical pins 92 which pass through the two slots 78 of the tube 76, this tube being received as a sliding fit within the tube 90. The right-hand end of the tube 90 has a single spigot 94 extending downwardly therefrom again to be received in one of the apertures 32 of the vice members of the workbench.

Arranged to cooperate with the holes 66 in the pillars 62 and 64 are either generally U-shaped or V-shaped abutments 100 having spigots 102 or a flat abutment 104 having a pair of spaced spigots 106. The abutments 100 and 104 can be inserted in the apertures 66 of the pillars 62 and 64 either in their opposed faces or in their outwardly facing faces where the abutments can be biased away from each other to grip the inside surface of a drum, for instance.

With the construction shown in Figures 2 and 3 workpieces can be clamped between the pillars using appropriate abutments to suit the workpieces. The spacing between the pillars can be finely adjusted by means of the vice handles of the workbench but if the spacing between the pillars cannot be appropriately adjusted to the required width, due to inadequate length of the screws 22, the pillar 64 can be coarsely adjusted with respect to the tube 90 by disengagement of the slots 86 from the pins 88, lifting of the pillar off the tube 90 and realigning the pillar 64 with a different pair of pins 88. This enables the device of Figures 2 and 3 to be used for clamping very wide workpieces which could not normally be clamped within the space between the vice members 10 and 1 2 of the workbench.Further adjustment of the spacing between the pillars 62 and 64 can of course also be obtained by insertion of the spigots 80 and 94 into different apertures 32 of the workbench.

Figure 4 shows a third embodiment which is basically of the same type as that of Figures 2 and 3 but instead of relying on a pin and slot connection between the two tubes 76 and 90, the dimensions of the external surfaces of the tube 76 and the internal surfaces of the tube 90 are determined such that the tubes are a close fit and can accommodate the loads imparted during clamping.

As with the first embodiment, clamping loads in either of the second or third embodiments produce similar offset loads on the jaw, the righthand pillar 62 tending to rotate clockwise and the left-hand pillar 64 tending to rotate anticlockwise. The pin and slot connection of the embodiment of Figures 2 and 3 or the tubular connection of the embodiment of Figure 4, like the pin and slot connections of the first embodiment, absorbs these offset loads by transmitting the tendency to rotation into the guidance provided by either the pin and slot connections or the tubular connections so that there is no tendency for the pillars to rotate the spigots 80 and 94 either to cause damage to the workbench top or to cause inadequate gripping due to line contact when surface contact may otherwise be obtained and maintained.

Figure 5 illustrates a further embodiment which incorporates two jaw structures each including a horizontal rectangular plate 120, the plate being mounted with its wider face extending vertically.

Each plate 120 carries at one end a spigot 122 for engaging in an aperture in a vice member 124 of a workbench.

The upper edge 126 of the plate has in it three t-shaped slots 128 to locate a base of an abutment, the base being generally indicated at 130 and comprising a saddle including side webs 132 and 134 and a horizontal web 136. The base has a transverse pin 138, which lies within the slot 128, to locate the base with respect to the plate 1 20. The web 136 carries an adjustment screw 140 by means of which the base 130 can be tilted slightly about the pin 1 38 when it is desired to position the abutment at a slight angle.

Upstanding from the web 136 is a rectangular post 1 44 which is received within the lower end of a tubular abutment 146 having an internal rectangular bore 148. Two opposite faces of the abutment 146 carry a suitable friction material 1 50 whilst the other two faces have in them apertures 1 52 to receive either a generally Vshaped abutment 1 54 or a self-aligning abutment 1 56 which is provided with side flanges 1 58 and 160 to locate around the abutment 146 and to be secured thereto by means of a pin 1 62 extending through apertures 1 64 in the flanges 1 58 and 1 60 and through the apertures 1 52 in the abutment 146.

Each plate 120 has in it an elongate horizontal slot 1 70 through which extends a pin 1 72 carried by the inside face of the other plate 120, each pin 1 72 having a head 1 74 to locate the two plates with respect to one another so that the two structures formed by the plates form a unified clamping mechanism.

It is to be noted that in contrast to the previous embodiments the spigot 122 of each plate 120 is situated at the opposite end to that of the abutment 146 so that, in this case, to obtain a clamping movement between the abutments the vice member 124 has to be moved away from the stationary vice member 125.

To the left in Figure 5 an alternative form of an abutment 1 80 is shown having two rows of teeth 182, for example for use in clamping logs.

Figure 6 shows a further embodiment in which a clamping mechanism is formed by two identical structures plus a separate interconnecting bar.

Thus each structure includes an abutment face 200 mounted rigidly on a vertical plate 202 having a spigot 204 at its lower end for engagement in an aperture in a vice member 206 of a workbench as in the other embodiments. The plate 202 has an integral forward extension 208 of generally triangular form which carries on one side thereof a headed pin 210. Projecting from the plate 202 on the same side as the pin 210 at a level slightly below the lower end of the abutment 200 is a further headed pin 212 which is spaced horizontally and vertically from the first pin 210.

The two pins 210 and 212 have shank portions of which upper and lower surfaces thereof respectively afford thrust surfaces for engagement with a rectangular bar 214 having a vertical width substantially equal to the spacing between the thrust surfaces referred to.

The two structures providing the abutments 200, the spigots 204 and the headed pins 210 and 212 are of identical form except that one is left-handed and the other right-handed to position the headed pins all on the same side.

Operation of this mechanism is similar to previous embodiments. A workpiece is situated between the two abutments 200 and, by operation of twin screws of the workbench having the structures carried thereon, the abutments can be drawn together. When clamping takes place any tendency for the faces of the abutments 200 to tilt about horizontal axes is restrained by engagement of the bar 214 between the upwardly and downwardly facing thrust faces of the shanks of the headed pins 210 and 212 respectively which engage the lower and upper faces of the bar 214. In this way the rotary forces tending to open up the gap between the abutment faces are cancelled out by transfer of the forces through the bar 214 as in previous embodiments.Here again therefore good contact is maintained between the abutment faces and the workpiece for excellent clamping and the spigots 204 do not tend to tilt within the bores in which they are received in the vice members and hence do not damage these bores.

Figure 7 shows an embodiment having similarities to the embodiment of Figure 6 except that only two cooperating structures are included.

Each includes an abutment 300 positioned on a vertical limb 302 of an L-shaped plate having a horizontal limb 304. Each structure includes a spigot 306 welded to the underside of the structure at the join of the limbs 302 and 304 and which engages in a bore in a vice member of a workbench as in previous embodiments.

Extending sidewards from each limb 302 adjacent its lower end is a headed pin 308 having a shank 310. It is arranged that the horizontal limb 304 of one structure has a vertical and horizontal dimension which positions it closely between the other spigot 306 and the other headed pin 308 as shown. This locates the two structures with respect to one another and positions the two limbs 304 in contact with one another. In this way the two structures are guided for horizontal movement and again, like other embodiments, any tendency for the structures to rotate about horizontal axes during clamping is counteracted by engagement of the shanks 310 of the pins 308 with the upper edges 312 of the horizontal limbs 304.

It will be appreciated that in this embodiment the two structures are identical and do not have to be left-handed and right-handed.

Figure 8 illustrates diagrammatically an attachment similar to previous embodiments in which two upstanding abutments 400 again have integral horizontal interconnecting portions 402 provided with pin and slot connections. In this case a workpiece, for example a tube 404, can be suspended between the abutments 400 at a suitable clamping position by means of a strap 406.

Figure 9 shows a similar embodiment in which a strap 408 is employed to hold a workpiece 410 downwards between abutments 412.

Figure 10 shows a further embodiment which can be utilised for clamping extremely wide workpieces. Figure 10 illustrates diagrammatically a workbench having a fixed vice member 500 and a movable vice member 502, the latter being actuated by a pair of horizontally spaced vice operating screws, now shown. Each clamping mechanism includes an elongate round bar 504 which can be supported during use of the clamping mechanism by any suitable support 506.

Each clamping mechanism includes a first abutment 508 extending upwards from a sleeve 510 having lower flanges 512 by means of which the abutment 508 can be rigidly clamped at any desired position along the length of the bar 504.

The right-hand end of each bar 504 is secured rigidly to a further sleeve 514 to which is welded a horizontally extending plate 516 having in it an elongate horizontal slot 520. The second abutment 522 also has an integral sleeve 524 at its lower end, and welded to one face of the sleeve 524 is a further horizontally extending plate 51 8 also having in it an elongate horizontal slot 526. In the case of the slot 526, a headed pin 528 extends from the sleeve 514, and in the case of the slot 520 a headed pin extends from the sleeve 524.

The sleeves 514 have downwardly extending spigots 530 for engaging in vertical bores in the fixed vice member 500 whilst the other sleeves 524 have downwardly extending spigots 532 for engagement in vertical bores in the movable vice member 502.

Operation of this embodiment is basically similar in principle to previous embodiments. Thus the two sets of abutments 508 and 522 can be drawn towards one another by operation of the vice screws of the workbench to move the movable vice member 502. Again any tendency for the abutments 508 and 522 to rotate about horizontal axes is transmitted via the clamping mechanisms and the pin and slot connections therein to the other abutment thereby cancelling out these rotational forces.

Figure 11 shows an arrangement similar to that shown in Figure 6 in that a separate interconnecting bar extends between the jaws.

The attachment has two identical or similar jaw structures each of which consists of a jaw carrier 602 having an integral depending spigot 603 for engagement in an aperture in one of the vice members of the workbench. Each jaw carrier 602 has a vertical elongate slot 604 so that it can slide in relation to a clamp load reaction bar 605 which extends across the width of the workbench in a manner similar to the bar 214 in Figure 6. The jaw carriers 602 are spaced apart along the length of the bar 605, and stops 606 prevent them from sliding off the ends of the bar. The bar 605 is a snug sliding fit in the slots 604 in the jaw carriers so that the jaw carriers are not capable of rotation about an axis parallel to the axis 607, that is a horizontal axis transverse to the length of the bar 605.

Each jaw carrier 602 carries a pivotally mounted jaw 608 and the pivot consists of a pair of pins 609, one in each of a pair of parallel jaw plates 611, one on either side of the jaw carrier 602. The pins 609 extend through holes in the plates 611 into slots 612 in the sides of the jaw carrier, and the pins have heads locating them laterally.

There are three cylindrical spacers 614 spaced apart between the jaw sides 611, and the lowermost spacer 614 can locate in any one of a row of notches 615 formed in the upper surface of the jaw carrier 602.

It will be seen that coarse adjustment of the position of the jaw along the jaw carrier can be made by pivoting the jaw forwards about the pivot pins 609, to remove the lowermost spacer 614 from its notch 615, and then sliding the pivot pins 609 along their slots 612 until the jaw can be rocked back with the lowermost spacer 614 in the chosen notch 61 5.

A spring loaded detent 617 is mounted in the outside of one of the jaw plates 611 , and has a domed inner end which is spring urged into engagement with any one of a number of dimples 61 8 situated above the slot 612 and each corresponding in position to one of the notches 61 5 so that once the coarse position of the jaw has been chosen, the detent 617 will engage in the corresponding dimple and retain the jaw in position. A toggle handle 619 can be pressed to withdraw the detent 617 from its dimple 618 so that coarse adjustment can be made using one hand only.

To one or each of the jaws 608 thereof there is pivoted a workpiece support finger 670 (only one of which is shown in Figure 11). Each finger 670 is pivoted by means of a pin 671 to the side face of the respective jaw opposite to that which carries the toggle handle 619, and can be rotated anticlockwise about the pin 671 from the erected operative position shown in Figure 11, in which it rests on one of a pair of spigots 621 and projects horizontally inwardly towards the oppdsite jaw, to a folded position (not shown) in which it hangs down vertically against the side of the jaw 608 clear of the working space between the opposed pair of jaws.In its erected position the finger 670 will extend below and clear of any shorter jaw face such as 626 or 629, shown in Figures 1 lA and 11 B respectively, which may be mounted on the top of the jaw 608, and it will serve to support a workpiece prior to this being gripped between the opposed jaws. Thus, a heavy or awkwardlyshaped workpiece which is to be gripped between the opposed jaws 608 can be rested on the erected finger 670 of one or each jaw when initially introduced into the space between the widely-separated jaws, and will be supported on the finger or fingers and steadied by one hand of the operator whilst with the other hand he turns the vice operating handles to bring the vice members and the jaws 608 towards one another to clamp the workpiece between the jaws.When not required to support a workpiece in this way the finger or fingers can be folded back clear of the space between the jaws.

The pair of transverse jaw attachment locating spigots 621 can have a jaw face 625 quite simply hooked thereon by virtue of pairs of slots 622 in rearwardly facing spaced side walls 623 of the body of the jaw face.

There may be a number of different jaw faces capable of attachment to the jaw spigots 621. A plate face 625 is shown in Figure 11. Figure 11 A shows a face 626 which embodies a vertical pivot pin 627 between the face plate 626A and the slotted body 626B so that the face plate 626A can turn about a vertical axis in relation to the body 626B and the jaw 608. A third possibility shown at 629 in Figure 11 B has a V-shaped jaw face plate 631 on a horizontal pivot 632. Both of the faces 626 and 629 shown in Figures 11 A and 11 B can be hooked onto the jaw attachment locating spigots shown in Figure 11 by virtue of slots which are present in rearwardly facing spaced side walls, in the same way as the jaw face 625 of Figure 11 is hooked.

The jaw assembly can be easily mounted on a workbench using the two spigots 603, and fine spacing apart of the two jaw carriers can be set using the bench handles which operate the vice.

Two of the complete jaw assemblies of Figure 11 may be used, respectively mounted at opposite ends of the workbench so as to provide two pairs of cooperating jaws, each pair of which can be adjusted independently of the other pair by means of the bench handle at the respective end of the bench.

The jaws are erected from the stowed position shown in chain lines at 634 to the position shown in solid lines in which the front faces of the sides 611 are perpendicular to the bar 605. The jaws are then slid to the coarse adjustment positions to enable the workpiece to be inserted between them, and then they are clamped onto the workpiece by using the bench handles.

Claims

1. An attachment for clamping mechanism of the type specified comprising a pair of interconnected structures each having an abutment for clamping against a workpiece and a base portion which has at least one downwardly extending spigot to be received in one of the upwardly extending holes or recesses of the clamping mechanism, the structures being interconnected so as to permit a sliding movement between them to vary the gap between the abutments whilst restraining the abutments from tilting movements about substantially horizontal axes generally perpendicular to the direction of sliding movement during clamping of a workpiece between them whilst mounted on the clamping mechanism and during operation of the vice operating means.

2. An attachment as claimed in Claim 1 in which each structure has a horizontally extending interconnecting portion, the two interconnecting portions having at least one pin and slot connection extending between them.

3. An attachment as claimed in Claim 2 in which each interconnecting portion comprises an elongate plate having a wider surface thereof extending vertically and lying adjacent to or in contact with the other plate.

4. An attachment as claimed in Claim 3 in which each plate has an elongate horizontal slot through which extends a pin secured to the other plate to provide said pin and slot connections.

5. An attachment as claimed in Claim 1 in which each structure has a horizontally extending interconnecting portion integral with and extending from its respective base portion towards the other base portion, and each base portion having a downwardly facing thrust surface engaging an upwardly facing thrust surface of the other interconnecting portion.

6. An attachment as claimed in Claim 1 in which each base portion has a pair of vertically and horizontally spaced thrust members, the upper thrust member facing downwardly and the lower thrust member facing upwardly, and a separate interconnecting bar arranged to extend horizontally between the pair of thrust members at each end.

7. An attachment as claimed in any one of the preceding claims in which each abutment is separable from its base portion.

8. An attachment as claimed in any one of the preceding claims in which each abutment has more than one abutment face and can be positioned in different orientations with respect to the base portion in order to arrange for different abutment faces of the abutments to face one another.

9. An attachment as claimed in any one of the preceding claims in which each abutment has opposed workpiece engaging teeth.

10. An attachment as claimed in Claim 2 in which each structure has at least one horizontally extending portion which includes a ramp surface arranged to bias the workpiece upwards on separation of the abutments.

11. An attachment as claimed in any one of the preceding claims in which one structure is identical to the other.

12. An attachment as claimed in Claim 1 in which each structure has a horizontally extending interconnecting portion, the two interconnecting portions comprising telescoping tubes.

13. An attachment as claimed in any one of the preceding claims in which at least one abutment is capable of coarse adjustment with respect to the spigot of that structure.

14. An attachment as claimed in Claim 1 including a pair of jaw carriers each having a jaw providing a different one of the abutments and a base portion which has at least one of the downwardly extending spigots, at least one of the jaws being capable of being positioned on its carrier in a selected one of a number of defined positions.

1 5. An attachment as claimed in Claim 14 in which each jaw is mounted on its carrier through at least one pin and slot connection extending in the direction of the width of the gap.

16. An attachment as claimed in Claim 15 in which the carriers are interconnected by a beam extending in the direction of the width of the gap.

1 7. An attachment as claimed in Claim 1 6 in which are least one carrier can slide in relation to the beam, but cannot turn away from the other carrier about a horizontal axis perpendicular to the length of the beam.

1 8. An attachment as claimed in any of Claims 14 to 1 7 in which at least one jaw carrier has a line of teeth or stops, and its jaw has a member capable of locating against a selected one of the stops in each of the defined positions.

1 9. An attachment as claimed in Claim 1 8 in which movement of the jaw between two defined positions is achieved by pivoting the jaw in relation to the carrier sliding the jaw and then pivoting it back against a new stop.

20. An attachment as claimed in any of Claims 14 to 19 including manually releasable spring loaded means for locating a jaw in each of the defined positions.

21. An attachment as claimed in any of Claims 14 to 20 including one or more separable jaw faces.

22. An attachment as claimed in any of Claims 14 to 21 in which one or each of the jaws carries a movable support member which can be moved between an operative position in which it extends generally horizontally into the space between that jaw and the opposite jaw of the attachment and is so supported by the jaw so as to be capable of supporting a load rested on it, and a retracted position in which it lies clear of the space between the opposed jaws.

23. An attachment as claimed in Claim 22 in which the or each support member is pivotally attached to the jaw for rotation about a horizontal pivot axis transverse to the direction of sliding movement of the jaw carriers, and when rotated to its horizontal operative position the support member rests on an abutment of the jaw.

24. An attachment for a workbench of the type incorporating a top structure in the form of a vice formed by a pair of elongate vice members having vice operating means for drawing them towards and away from one another and a number of upwardly extending holes or recesses opening through the top surface of each vice member, the attachment comprising a pair of structures affording abutments having upwardly extending tooth portions facing each other, a base portion on each structure and provided with at least one downwardly extending spigot to be received in one of the upwardly extending holes or recesses of the workbench, and interconnecting portions one on each structure which overlap one another and which include a horizontal slot in each interconnecting portion which is engaged by a pin secured to the other interconnecting portion to permit a sliding movement between the structures to vary the gap between the abutments and to restrain the abutments from tilting movements about horizontal axes during clamping of a workpiece between them whilst mounted on the workbench and during operation to the vice operating means,

25.An attachment for a workbench of the type incorporating a top structure in the form of a vice formed by a pair of elongate vice members having vice operating means for drawing them towards and away from one another and a number of upwardly extending holes or recesses opening through the top surface of each vice member, the attachment comprising a pair of structures each of which includes a horizontal bar having at one end a downwardly extending spigot to be received in one of the upwardly extending holes or recesses of the workbench and at the other end an upwardly extending abutment for clamping against a workpiece, each bar having a horizontal elongate slot in which a pin carried by the other bar is received, thereby to maintain the two bars in parallel sliding relationship and to restrain the abutments from tilting movement about horizontal axes during clamping of the workpiece between them whilst the attachment is mounted on the workbench and during operation of the vice operating means.

26. An attachment as claimed in any one of the preceding claims in which each abutment is mounted for movement about a horizontal axis with respect to the associated spigot by means of an adjustment mechanism which rigidly locates the abutment with respect to the spigot at different inclinations.

27, An attachment for a clamping mechanism of the type specified comprising a pair of jaw carriers each having a jaw for clamping against a workpiece and a base portion which has at least one downwardly extending spigot to be received in one of the upwardly extending holes or recesses of the clamping mechanism, the carriers being interconnected so as to permit a sliding movement between them to vary the gap between the jaws whilst restraining the jaws from tilting movements away from each other about horizontal axes perpendicular to the width of the gap during clamping of a workpiece between them whilst mounted on the clamping mechanism and during operation of the vice operating means, at least one of the jaws being capable of being positioned on its carrier in a selected one of a number of defined positions.

28. An attachment for a clamping mechanism incorporating a structure in the form of a vice formed by a pair of vice members having vice operating means for drawing them towards and away from one another in a generally horizontal plane, the vice members having opposing clamping faces of restricted depth, and a number of upwardly extending holes or recesses opening through the top surface of each vice member, the attachment having a pair of abutments for clamping against a workpiece, which abutments afford opposed clamping faces of greater depth than those of the vice members, the attachment comprising a pair of interconnected structures each having one of the abutments and a base portion which has at least one downwardly extending spigot to be received in one of the upwardly extending holes or recesses of the clamping mechanism, the structures being interconnected so as to permit a sliding movement between them to vary the gap between the abutments whilst restraining the abutments from tilting movements about substantially horizontal axes generally perpendicular to the direction of sliding movement during clamping of a workpiece between them whilst mounted on the clamping mechanism and during operation of the vice operating means.

29. An attachment for a clamping mechanism incorporating a structure in the form of a vice formed by a pair of vice members having vice operating means for drawing them towards and away from one another in a generally horizontal plane, the vice members having opposing clamping faces and the structure being such that a workpiece extending along the complete length of the vice members and being clamped by the opposing clamping faces is restricted in the depth to which it may extend below the vice members, and a number of upwardly extending holes or recesses opening through the top surface of each vice member, the attachment having a pair of abutments for clamping against a workpiece, which abutments, when mounted on the clamping mechanism, afford opposed clamping faces at a greater height than those of the vice members to allow a workpiece being clamped by the opposing clamping faces of the abutments to extend to a greater depth below the attachment clamping faces than the depth to which the workpiece could extend below the clamping faces of the clamping mechanism when calmped between the pair of vice members, the attachment comprising a pair of interconnected structures each having one of the abutments and a base portion which has at least one downwardly extending spigot to be received in one of the upwardly extending holes or recesses of the clamping mechanism, the structures being interconnected so as to permit a sliding movement between them to vary the gap between the abutments whilst restraining the abutments from tilting movements about substantially horizontal axes generally perpendicular to the direction of sliding movement during clamping of a workpiece between them whilst mounted on the clamping mechanism and during operation of the vice operating means.

30. An attachment for a clamping mechanism of the type specified, the attachment including a pair of interacting structures, each of the structrues comprising a substantially L-shaped member including a generally horizontally extending portion and an upwardly extending portion affording an abutment for clamping against a workpiece, each of the structures having a base portion including at least one downwardly depending spigot, the base portion being in the region where the generally horizontal and the upwardly extending members meet with one another, and each of the spigots is to be received in a different one of said upwardly extending holes or recesses of said clamping mechanism, each of the base portions having a downwardly facing thrust surface, and each of the generally horizontally extending members having an upwardly facing thrust surface, each of the horizontally extending members being arranged to be co-extensive with one another whereby an upwardly facing thrust surface of each of the generally horizontally extending members interacts with a downwardly facing thrust surface of the other structure so as to permit a sliding movement between the structures to vary the gap between the abutments whilst restraining the abutments from tilting movements about substantially horizontal axes generally perpendicular to the direction of sliding movement during clamping of a workpiece between them whilst mounted on the clamping mechanism and during operation of the vice operating means.

31. An attachment for a clamping mechanism of the type specified, the attachment including a pair of structures and a bar extending between the structures, each of the structures including an upwardly extending member affording an abutment and a base portion including a downwardly extending spigot, each of which spigots is to be received in a different one of the upwardly extending holes or recesses of the clamping mechanism, each of the structures including an upwardly facing and a downwardly facing thrust surface and the bar including a downwardly facing and an upwardly facing thrust surface in the region of both strucutres, the downwardly facing thrust surfaces on each of the structures being spaced further from each other than the upwardly facing thrust surfaces, whereby the upwardly facing and downwardly facing thrust surfaces at either end of the bar act respectively against the downwardly facing and upwardly facing thrust surfaces of each of the structures so as to permit a sliding movement between the structures to vary the gap between said abutments whilst restraining the abutments from tilting movements about substantially horizontal axes generally perpendicular to the direction of sliding movement during clamping of a workpiece between them whilst mounted on the clamping mechanism and during operation of the vice operating means.

32. An attachment for a clamping mechanism substantially as described herein with reference to Figure 1, Figures 2 and 3, Figure 4, Figure 5, Figure 6, Figure 7, Figure 8, Figure 9, Figure 10, Figures 11, Figure 11 A or Figure 11 B, of the accompanying drawings.

33. A workbench having a top structure in the form of a vice comprising a pair of elongate vice members, one of the vice members being arranged for movement towards and away from the other vice member either in parallel manner or in a manner which enables one end of the movable vice member to be drawn nearer to the other vice member, each vice member having a number of upwardly extending holes or recesses opening through its top surface, and an attachment carried by the vice members comprising a pair of interconnected structures each having an abutment for clamping against a workpiece at a level above the surface of the vice members, and a base portion which has at least one downwardly extending spigot received in one of the upwardly extending holes or recesses of the vice members, one spigot being received in a hole or recess in one vice member and the other spigot being received in a hole or recess of the other vice member, the two structures being interconnected so as to permit a sliding movement between them to vary the gap between the abutments whilst restraining the abutments from tilting movements about horizontal axes during clamping of a workpiece between them and during operation of the vice operating means.

34. A workbench having a top structrue in the form of a vice comprising a pair of elongate vice members, one of the vice members being arranged for movement towards and away from the other vice member either in a parallel manner or in a manner which enables one end of the movable vice member to be drawn nearer to the other vice member, each vice member having a number of upwardly extending holes or recesses opening through its top surface, and an attachment as claimed in any of Claims 1 to 32 in which the two jaw carriers or interconnected structures are coupled to the respective vice members by virtue of the downwardly extending spigots being in the upwardly extending holes or recesses in the respective vice members.