BACKGROUND OF THE INVENTION Standard routers normally take- the form of a router head mounted on a specially constructed base plate by means of two spaced pillars. The router head is reciprocally removable on the pillars for adjustment of the distance between the head and the base plate thereby to set the depth of cut as between the router tool mounted to the head and projecting through an aperture in the base plate, and a workpiece positioned beneath the base plate.

The base plate is provided with parallel guide tracks for the insertion of guide rods and along which the base plate is movable with respect to a guide fence for the workpiece. The movement of the base plate along the guide rods is transverse to the direction of movement of the router head on the support pillars.

The router head is conventionally provided with hand grips which are attached to arms which

extend in-line to either side respectively of the router head.

A router stand is already in use to which is mounted a router machine of a special design which is operated by means of a foot actuated pedal beneath the work bench of the stand, to the extent that actuation of the foot pedal causes a rise and fall movement of the router head by means of a rack and pinion coupling. The coupling is fixed in the sense that the rack and pinion movement serves to reciprocate the router head with respect to the workpiece along a vertical axis and is therefore only suitable for fixed head routing. Moveover the system is restricted by design and cost essentially to use in the general machine shop and does not have those attributes which are necessary for general acceptance by the DIY operator particularly from the cost point of view. SUMMARY OF THE INVENTION

It is an object of the present invention accordingly to provide a jig for a routing machine of standard usage, the jig being designed so that it may be easily attached to the standard machine to permit the routing head to be reciprocated in the jig by means, preferably, of a bowden cable drive actuated by a foot pedal.

By this means both hands of an operator are left free to handle the workpiece in contrast to prior art usage. As far as an improvement over the rack and pinion drive arrangement described above is concerned, the use of an independently mountable jig means that the jig can be adapted for rotatable and pivotal mounting so permitting the angle of attack of the tool of the routing head to be varied as the need arises without changing the tool itself. This has important applications as will be appreciated by the man skilled in the art.

According to the present invention there is provided a jig for a routing machine having a router head reciprocally movable along its axis on spaced guide pillars with respect to a base plate therefor and adapted to guide a tool of the router with respect to a workpiece the jig comprising a support cradle for the routing machine, router head attachment means pivotally mounted on said support cradle, yieldable means for holding said attachment means at a starting pivotal position corresponding to a displaced position of the router head from said base plate, and drive means for actuating said attachment means whereby to move the router head from said displaced position to

selected positions intermediate said displaced position and said base plate.

The attachment means preferably takes the form of a pair of parallel arms respectively pivotally mountable to the existing arms of a standard router head extending to either side thereof.

The drive means is preferably in the form of a bowden cable, the inner cable of which is attachable to the base plate and the outer sheath to the pivotally mounted attachment means whereby actuation of the bowden cable as by foot pedal operation varies the distance between the router head and the base plate as desired.

Other features and advantages of the present invention will become apparent from the disclosure which follows in relation to preferred embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS A preferred embodiment of the present invention will now be described by way of example with reference to the accompanying drawings wherein:

Fig 1 is a perspective view in outline of a standard router machine with support base plate; and Fig 2 is a perspective view of a jig for mounting the router shown in Fig 1 to a work bench.

BEST MODES OF CARRYING OUT THE INVENTION The standard router shown in Fig 1 comprises a router head 1 having in line transversely extending arms 2 to which are attached hand grips (not shown) for manipulating the router head 1 as required. The router head 1 is mounted for reciprocal movement with respect to a specially constructed base plate 3 on two pillars 4.

A router tool (not shown) attached to the router head 1 extends through an aperture 5 in the base plate 3 to engage a work piece positioned beneath the plate 3 and against a guide fence (not shown), as is well known in the art.

The surface of the base plate 3 is provided with two parallel guide tracks 6 through which guide rods of a micro adjustable guide fence are inserted to enable the router head to be moved transverse to its reciprocating axis to bring the router tool into engagement with the work piece held against the guide fence. The jig shown in Fig 2 is designed to be attached to the router shown in Fig 1, and comprises a flat support plate 7 for securing to the base of the base plate 3 of the router and then to a work bench. The support plate 7 is bounded by two side walls 8 and joined by a rear wall 9, to form a

support cradle C. A pivotal support structure for attachment to the router head comprises a rectangular frame 10 pivotally mounted at 11 to spaced uprights 12. The spaced uprights 12 are pivotally mounted respectively to the ends of a bar 13 which fits in assembly between -the side walls 8.

The parallel sides 14 of the frame 10 are each provided with centrally positioned holes 15. The outer sheath of the bowden cable 16 is secured to the side 17 of the frame 10 and the inner cable of the bowden cable to a tubular bar 18. The bowden cable is actuated by means of a pedal drive shown schematically at 19.

A flange 20 attached to the rear wall 9 supports a block 21 comprising transversely arranged tubular grips 22 and 23.

This permits the cradle provided by the support plate 7 and side walls 8 and 9, to be attached to tubular supports of the work bench via tubular grips 22 and 23 thereby to provide for rotational movements of the cradle C and the routing machine mounted therewithin, as will be described.

To mount the router as shown in Fig 1 in the jig as above described with reference to Fig 2, the bars 13 and 18 are first positioned in the channels 6 and retained therein by the channel bridges 6' .

The parallel arms 14 of the frame 10 are then respectively attached to the arms 2 extending from the router head 1 by means of suitable screw attachments inserted through the holes 15 in the arms 14.

The base plate 3 with the router 1 and the attached pivotal mechanism is then mounted bodily in the cradle C and the base plate 3.then secured to a support plate 7 of the cradle. To maintain the router at a maximum displaced position from the base plate, the frame 10 is ^' held at a maximum upper pivotal position by means of springs 24 held between projecting arms 25 attached to the ends of the uprights 12 as show. The disposition of the various connecting members of the pivotal structure attached to the router head is such that as the bowden cable is actuated the router head executes a vertical reciprocal movement thereby to permit the tool of the router to engage the workpiece by foot pedal action, within the parameters of a pre-set working depth.

Summarising the above preferred embodiment in a broad sense the invention provides a jig for a routing machine having a router head which is reciprocally movable along its axis on spaced guide pillars with respect to the base plate of the machine in order to guide a tool of the router with respect

to a work piece the jig comprising a pivotally mounted support for attachment between the router head and the base plate, means for urging the support means to maintain the router head at a displaced position from the base plate, and drive means for moving the head from the displaced position to selected positions intermediate the displaced position and the base plate.