A well known carpenter's workbench for the do-it-yourself enthusiast consists of a pair of juxtaposed elongate vice members having their upper surfaces lying in substantially the same horizontal plane to form a working surface. Such a bench is described, for example, in UK Patent 1,267,032. The vice members may each include an array of vertical holes for receiving clamping elements so that a workpiece can be clamped in place at various locations on the work surface.

It has already been proposed to provide such a workbench with a replacement worktop suitable for mounting power tools, but this has necessitated removing one of the vice members to fit the replacement. Moreover, the replacement worktop can only be fitted to a particular model of the workbench which is not in widespread use.

A more advanced carpenter's workbench in the form of a tooling jig is disclosed in UK Patent 1,529,642. This is intended not only for the do-it-yourself enthusiast, but also the professional wood worker. It would be an advantage if a worktop of this type could be fitted as an accessory to the type of workbench described in UK Patent 1,267,032.

According to one aspect of the present invention, there is provided an attachment for a portable workbench of the type comprising a pair of juxtaposed elongate vice members, the attachment comprising a worktop having an area exceeding the area of the vice members and means for releasably securing the worktop to the vice members; the securing means including at least one clamping member, and means for mechanically connecting the worktop to the clamping member, the connecting means including a screw connection whereby the vice members are clamped between the worktop and the

clamping member.

According to another aspect of the invention, there is provided a method of releasably securing a worktop to a portable workbench of the type comprising a pair of juxtaposed elongate vice members wherein the vice members are releasably clamped between the worktop and a clamping member retained against the underside of the vice members.

The clamping member preferably spaces the vice members a predetermined distance apart and is located against the end faces of the vice members so that one of a plurality of vertical holes in each vice member is aligned with a respective hole in the clamping member. Conveniently, the screw clamping mechanism of the workbench is operated until the vice members grip an upstanding portion of the clamping member to control the initial spacing between the two vice members.

The worktop is then located over the vice members and fixing holes in the worktop are aligned with those holes in the vice members previously aligned with the respective holes in the clamping member. The holes in the clamping members or the fixing holes in the worktop are provided. with a screw-thread for engaging a clamping screw inserted through the aligned holes. Further rotation of the screw then produces the clamping force.

The worktop itself preferably includes a pair of support rails and a removable section disposed transverse to the support rails whereby, with the section removed, an elongate gap is provided across the worktop, the gap being aligned with the corresponding gap between the vice members.

In the accompanying drawings, by way of example only:- Fig. 1 is a diagrammatic sketch illustrating a well known type of portable workbench, and showing part of a mechanism for securing a worktop to the workbench.

Fig. 2 is a plan view of a tooling jig worktop which may be fitted as an accessory to the workbench of Fig. 1.

Fig. 3 is a cross-section on line A-A of the worktop shown in Fig. 2.

Fig. 4 is a scrap cross-section illustrating the manner of securing the worktop of Fig. 2 to the workbench of Fig. 1.

Fig. 5 is a plan view of the lower clamping member of the securing mechanism, and

Fig. 6 is an end view of the clamping member shown in Fig. 5.

Referring to these drawings, Fig. 1 shows diagrammatically one end of a well known portable type of carpenter's workbench having a pair of elongate vice members or jaws 1 and 2 mounted on a free-standing collapsible support structure 3. The opposite end is similar. The upper surfaces of the jaws 1 and 2 lie in substantially the same horizontal plane and form a working surface. The jaws can be opened or closed at each end by independently operated screw-threaded vice operating devices 40 with an operating handle 41.

In Figs. 2 and 3. there is shown a tooling jig worktop 20 which consists of three panels 4, 5 and 6. The two outer panels 4 and 6 are secured to a sub-frame consisting of a pair of elongate metal bracket rails 29a, 29b. The bracket

rails 29a, 29b extend along two opposing sides of the worktop and are secured to the underside of the panels 4 and 6 by means of screws, one such screw 30 being shown in the section of Fig. 4.

The central panel 5 of the worktop extends between the xai s 29a, 29b and is removable. The central panel 5 may be slidably engageable with each of the side panels 4 and 6 using a tongue and groove engagement.

The bracket rails 29a, 29b are of -shaped section, with one arm 33 secured to the underside of the side panels 4 and 6 and the other arm 22 extending downwardly to provide an end stop. In this manner, with the width of the panels 4 and 6 being equal to the length of the jaws 1 and 2 of the workbench, the worktop 20 is fitted over the workbench by locating the end stops 22 of the worktop relative to the end faces 32 of the jaws.

The downwardly extending arms 22 of the angle section rails 29a, 29b not only act as end stops, but also project below the underside of the jaws 1 and 2 to provide runners for respective slidable support devices 42a, 42b which hook under the arms 22 and are secured to opposite ends of a cross fence 26. The devices 42a, 42b may include a vertical screw-thread such that the ends of the fence 26 can be raised and lowered relative to the worktop, and the fence can then be used additionally as a clamping bar for clamping a workpiece to the worktop.

The length of the side panels 4 and 6 along the sub-frame rails 29a, 29b exceeds the combined width of the workbench jaws 1 and 2 when the jaws are spaced apart as shown in Fig. 1 so that the side panels 4 and 6 overhang the workbench on both sides of the jaws.

The worktop includes an array of 20mm holes 25 which are used to locate workpiece clamping devices (not shown) of the type described, for example, in UK patent application 8699399. The worktop provides a base for a variety of machine tool operations including in particular cross- cutting and rip-cutting. For cross-cutting, the worktop may additionally include a longitudinally extending location fence (not shown) defining a straight edge, and a bridge (not shown) which is directly secured to the location fence and positioned to overlie a workpiece placed against the fence. A guideway on the bridge then extends accurately perpendicular to and intersecting the line of the straight edge, the guideway being adapted to guide a router or a saw accurately perpendicular to the straight edge. This cross-cutting, facility enables the production of very accurate right-angled edges to the workpiece, and the additional components not shown in the present drawings are more fully described, for example, in the aforesaid UK Patent 1,529,642.

The worktop further includes measurement rules 7 and 8 which enable the cross fence 26 to be set absolutely parallel with the direction of saw rotation during rip saw cutting. These rules are each set in a respective shallow rebate 15 along one edge of the worktop, but might alternatively be positioned inwardly of the edge and underprinted on a ^' protective phenolic or melamine film covering the surface of a plywood or chipboard base.

A longitudinal rebate channel 9 in the worktop is used to set up a mitre device (not shown) which slides in the channel and carries a workpiece past the saw blade. For rip cutting the saw is underslung relative to the worktop and is carried by a soleplate which replaces an inset sole

plate or panel 23.

The manner of securing the worktop 20 to the jaws of the workbench is as follows. A metal clamping strip 21 is first positioned beneath the workbench jaws 1 and 2 at each end of the workbench, each strip bridging the gap between the jaws at the respective ends. As shown in Figs. 1 , 4 and 5, a central portion 27 of this lower clamping strip 21 is cut away and bent upwards. The clamping strip 21 is thus held in place by closing the jaws 1 and 2 until they grip opposite ends of the upstanding cut-out 27. In this manner the jaws 1 and 2 are set a predetermined distance apart, and the centres of respective holes 17 in the strip 21 are aligned with the centres of two of the corresponding larger holes 13 in the jaws 1 and 2. The outside edge of the strip 21 also includes an upturned lip 31 for locating the strip against the end faces 32 of the jaws. The two holes 17 in the strip 21 are each press fitted with screw-threaded hank bushes 23 for receiving screw-threaded bolts 18 inserted through respective ones of corresponding fixing holes 34 in the worktop 20. The bolts 18 may carry captive nuts 43 to prevent inadvertent removal of the bolts from the fixing holes 34 in the worktop. These fixing holes 34 are visually aligned with the respective holes 13 in the workbench jaws after the worktop 2 has been located over the jaws by means of the end stops 22 projecting downwardly from the underside of the worktop. Alternatively, the worktop may include further projections for laterally locating the worktop relative to the jaws 1 and 2 such that the fixing holes 34 are automatically aligned with respective holes 13 when the worktop is located in position.

The worktop 20 is thus securely bolted to the workbench jaws, with the jaws being effectively clamped between the

7 worktop and the clamping strips 21.

One particular advantage of the described clamping arrangement is that the worktop is maintained perfectly level, even though the upper surfaces of the two workbench jaws may not be in exactly the same horizontal plane.

With the worktop 20 secured to the jaws 1 and 2 in this manner, the central removable panel 5 of the worktop is automatically aligned with the gap 19 between the jaws, and the side panels 4 and 6 overhang the jaws 1 and 2 on each side to provide a large stable working surface. In particular, the area of the removable sole plate or panel 23 lies at least partly outside the area defined by the jaws 1 and 2.

The alignment of the gap between the two side panels 4 and 6 with the -gap 19 (Fig. 1) between the two jaws of the workbench has a number of advantages. It is used firstly during cross-cutting so that the saw blade can rotate freely below the level of the workpiece. It also provides a convenient outlet for the removal of dust and swarf from the work surface.

It also facilitates a number of woodworking operations which require a flat surface for supporting one workpiece and provision for holding another workpiece at a different angle, usually 90°. For example, many mechanical methods of connecting panels in cabinet construction require two workpieces clamped at 90° to one another, with the controlled introduction ^' of a cutting machine, usually a router, which moves across or into both workpieces. In the present case, one workpiece is clamped vertically in the gap between the two side panels (using any convenient form of clamp), and the other workpiece is clamped horizontally

8 to the surface of one or other of the side panels 4 and 6 using clamping devices engaged in the holes 25.

The width of the gap between the worktop panels 4 and 6 with the centre panel 5 removed preferably exceeds the width of the gap between the jaws 1 and 2 set by the clamping strip 21. The exposed portions of the jaws 1 and 2 then provide useful ledges within the gap between the panels 4 and 6.

A further advantage of the present worktop is that a wide variety of power tools can be suspended from a soleplate fitted in the recessed area 23. With the maximum gap between the jaws of the original workbench 3 shown in Fig. 1 being about lOcms, this would not have been possible using the workbench alone. The additional facility has been achieved without the need to remove one of the workbench jaws, and also provides a much greater work area. Moreover, although the area 23 lies at least partly outside the area defined by the jaws of the workbench 3, it is positioned well within the area defined by the support legs of the workbench, and the structure is therefore fully stable.

The disposition of the holes 25 in the worktop 20 is such that a workpiece can be clamped at either 45° or 90° to the cross-cutting direction and thereby provides a simple means to cutting work to these angles.