GB2448189A

GB2448189A - Jig for mounting a cutting tool to a workbench

Info

Publication number: GB2448189A
Application number: GB0706803A
Authority: GB
Inventors: Alan David North
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-04-05
Filing date: 2007-04-05
Publication date: 2008-10-08
Anticipated expiration: 2027-04-05
Also published as: EP2142336A1; WO2008122757A1; GB0706803D0; GB2448189B

Abstract

A jig 10 is provided for mounting a cutting tool such as a router 11 to a work bench. The jig comprises a carriage 14 for mounting the cutting tool, first track means for guiding movement of the carriage along a first path, and second track means for guiding movement of the carriage along a second path perpendicular to the first. The jig further comprises means (17a, 17b, 18a, 18b) for attachment of the jig to a workpiece holding device in use, such as a jaw 50 of a workbench. Preferably, the means for attaching the cutting tool to the carriage includes third track means for guiding movement of the cutting tool along a third path perpendicular to both the first and second paths. Movement of the carriage between operative and inoperative positions may be arcuate, and releasable latching means 31, 32 may be provided for holding the carriage in its operative position.

Description

S

Improvements in cutting tool mounting assemblies This invention relates to a jig for mounting a cutting tool, in particular though not exclusively, a router.

Hand-held routers are usually used by moving the tool relative to a fixed workpiece, often using a fence or template to guide its movement. It can be difficult, however, to produce accurate cuts across thin or small The present invention provides a jig for mounting a cutting tool such as a router, said jig comprising a carriage having means for attaching a cutting tool thereto in use, first track means for guiding movement of said carriage along a first path, second track means for guiding movement of said carriage along a second path perpendicular to said first path, the jig further comprising means for attachment of the jig to a workpiece holding device such as a portable work bench, in use.

By way of example, embodiments of the invention will be described with reference to the accompanying drawings, in which: Figure 1 illustrates an embodiment of a jig according to the present invention, Figure 2 illustrates the jig of Figure 1, with a router mounted thereon, Figure 3 illustrates the jig of Figure 2 with the router in its inoperative position, Figure 4 is an exploded view illustrating the main components of the jig of Figures 1, 2 and 3, and

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Figure 5 illustrates a further alternative use of the jig of Figures 1 to4.

A jig 10 for mounting a cutting tool is seen in Figures 1 and 2.

The cutting tool may be a typical hand-held electrically powered plunge router 11 (see Figure 2), as used by many woodworkers and DIY enthusiasts.

The router 11 is fixed to a platen 12 on the jig 10 by suitable means such as bolts. As will be seen, the platen 12 has a hole 13 therein to enable a cutter bit (not shown) held in the router 11 to engage with the workpiece. The platen 12 is itself carried by a carriage 14 on the jig 10 by means of a slidable connection, here in the form of an extruded dovetail section 15. The position of the platen 12 relative to the carriage 14 can be adjusted along a vertical axis y (see Figure 1) and held in place by a releasable clamping bolt 16 (see Figure 4).

The carriage 14 is itself mounted for slidable movement relative to the jig 10 in two orthogonal horizontal axes x and z (See Figure 1), as will be explained in more detail below.

The jig 10 is itself designed to be mountable to a table or work bench. For this purpose, the jig 10 has two arms 17a, 17b which can be anchored by suitable means such as bolts 1 8a, I 8b. Ideally, the jig 10 can be mounted on one of the jaws of a portable work bench (J)referably the fixed jaw). This conveniently enables the router 11 to be deployed on work pieces held in the jaws (50, 51) of the work bench (see Figure 3).

Figure 3 illustrates a key feature of the jig 10, namely that it enables the router 1110 be swung out of the way into an inoperative position.

This is convenient in particular for allowing easy access to the jaws 50, 51 of the work bench for setting the workpiece in position. It may also facilitate changing over cutter bits in the router 11.

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The platen mounting arrangement comprises an elongate rod 20 and an elongate bar 21 that are each fixed at right angles to the platen 12 and extend in parallel therefrom. The rod 20 is of circular cross-section and is slidably held within an elongate guide sleeve 22. The bar 21 is of square cross-section and is slidably held by a bracket 23. Both the bracket 23 and guide sleeve 22 are fixed to a yoke piece 24. This arrangement ensures that the platen 12 is guided for reciprocable movement along the z axis (Figure 1).

The bracket 23 incorporates a releasable locking bolt 26 to clamp the bar 21 and thus enable the platen 12 to be held in a fixed position along the z axis, if desired. The bar 21 additionally incorporates adjustable end stops 27, 28 to act to limit the reciprocal movement of the platen 12 along the z axis.

The yoke piece 24 is itself in the form of an elongate guide sleeve and is mounted on a round-section rod 29 that extends between the two arms 17a, 17b of the jig 10 parallel to the x axis (see Figure 1). The yoke piece 24 is slidable along the rod 29. it will be noted that the arrangement also enables the yoke piece 24 to rotate about the rod 29. This enables the platen 12 to be swung between an operative position where the router 11 can engage a workpiece (seen in Figure 2) and an inoperative position where the router is disengaged from the workpiece, eg for setting up a new workpiece and/or changing a cutter bit (seen in Figure 3).

The platen 12 is deployed in its operative position by means of a bracket 30 fixed on the guide sleeve 22. The bracket 30 is engagable with a bar 31 extending between the two arms I 7a, I 7b parallel to the x axis, The bracket 30 incorporates a slidable latch 32. When the platen 12 is swung into its operative position, the bracket 30 will engage the bar 31 and if the latch 32 is slid over the bar 31, this will stop the platen swinging back out of position.

The bracket 30 has a releasable locking bolt 33 for clamping to the bar 31. If the locking bolt 33 is clamped down hard on the bar 31, this will hold the platen 12 in its operative position, but also prevent its movement along the x axis. If it is desired to enable the platen 12 to move along the x axis, the locking bolt 33 must be released sufficiently to allow the bracket 30 to slide along the bar 31. In use of the router 11, downward pressure on the router applied by the user will ensure that the bracket 30 remains in contact with the bar 31. The rod 29 and bar 31 together ensure that the platen 12 is guided for reciprocable movement along the x axis. The bar 31 further incorporates adjustable end stops 34, 35 to act to limit the reciprocal movement of the platen 12 along the x axis.

The jig 10 includes a facility for allowing the router 11 to make cuts to a set pattern. This takes the form of a pin 40 mounted on the carriage 14 which is engagable with a template 41. The template 41 is held in a fixed position relative to the jig 10 by means of a holding tray 43 which is bolted to one or other of the arms 1 7a, 1 7b. The pin 40 is mounted on the carriage 14 by means of a slotted bracket 42 to enable the position of the pin along the z axis to be adjusted to suit the workpiece set-up. This allows the possibility for the cutter bit of the router to be applied to the centre of the workpiece, for example when making mortice and tenon joints. The arrangement enables suitable adjustments to be made for different thicknesses of workpiece. With the pin 40 following the contours of the template 41, the router 11 will be guided to produce appropriate cuts in the workpiece. Different templates may be provided for producing different cutting patterns, such as dovetail joints, for example, or lettering.

It will be noted that the pattern cutting facility in this jig is arranged to be at one side of the router. In conventional pattern cutting arrangements, the template for the router to follow is typically situated beneath the router itself. The arrangement in the jig shown here is easier to use than these conventional arrangements and hence more reliably produces satisfactory results.

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The various components from which jig is made can be of any suitable material, eg lightweight metal. However, it is preferred to use extruded sections where possible, as this is less expensive to produce than cast S components. It is important to try to ensure smooth and accurate movement of the router along the x and z axes. Free running is especially important when the router is extended fully out along the z axis. This is achieved in the jig described above by providing that the rods 20 and 29 are of hardened and ground steel, with the guide sleeve 22 and yoke piece 24 incorporating linear ball races.

The bars 21 and 31 essentially serve to prevent rotation around the rods.

There is no need for such a high degree of accuracy, so it is acceptable to use bar material for these, rather than rod. It is important that the sliding contact of the bars is as friction free as possible, however, so the brackets 23 and 30 are provided here with a low friction material, eg Acetal pads, for the sliding contact surfaces with the bars. Another advantage of using bar material is that the clamping bolts on the brackets and on the end stops tend to work better than with rod, where there is a tendency for the bolts to rotate and dangle when released.

In use, the jig will ideally be bolted to the fixed jaw of a portable work bench. The workpiece can be positioned in the jaws whilst the router is in its inoperative position (Figure 3). If a detailed joint is to be made, the chosen template is fixed in position. The router can now be swung into its operative position and the latch slid into position to hold it there. The position of the pin on the carriage is now adjusted along the z axis relative to the template to suit the workpiece. The height of the router along the y axis is also adjusted. The router is now ready to perform the patterned cuts in the workpiece. The router is brought into final cutting engagement with the workpiece (along the y axis) using the plunge facility in the router itself.

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It will be appreciated that the jig described above enables the router to be manoeuvred with certainty along x and z axes, enabling a user to make cuts in even very small or thin workpieces -something that is normally very difficult to achieve with a toot of this kind.

As seen in Figure 5, the jig also enables the router to be used in the manner of a routing table. The router 11 is deployed in its operative position and fixed with respect to x, y and z axes using the clamping bolt 16 on the carriage 14 and the clamping bolts 26 and 33 on brackets 23 and 30 respectively. A block of wood 60 is clamped between the jaws 50, 51 of the work bench to form a fence. Workpieces can now be fed past the cutter bit 61, guided by the block of wood 60 acting as a fence. The ability of the jig to allow the router to be used in this way greatly adds to its versatility.

Claims

Claims 1. A jig for mounting a cutting tool, said jig comprising a

carriage having means for attaching a cutting tool thereto in use, first track means for guiding movement of said carriage along a first path, second track means for guiding movement of said carriage along a second path perpendicular to said first path, the jig further comprising means for attachment of the jig to a
2. A jig as claimed in claim wherein the means for attaching said cutting tool to the carriage includes third track means for guiding movement of the cutting tool along a third path perpendicular to both said first and second paths.
3. A jig as claimed in claim 1 or claim 2 and further comprising means enabling said carriage to be moved between an operative position where the cutting tool can work on a workpiece and an inoperative position.
4. A jig as claimed in claim 3 wherein the movement of the carriage between said operative and inoperative positions is arcuate.
5. A jig as claimed in claim 3 or claim 4 and further comprising releasable latching means for holding said carriage in its operative position.
6. A jig as claimed in any preceding claim wherein said workpiece holding device comprises a portable work bench with movable jaws for clamping workpieces, the jig being attached to the work bench in use with its jaws lying generally parallel to said first path.
7. A jig as claimed in claim 6 wherein the arcuate path of movement of the carriage between said operative and inoperative positions is about an axis parallel to said first path.
8. A jig as claimed in any preceding claim and further including releasable clamping means for holding the carriage in a chosen position along the first andlor second and/or third paths.
9. A jig as claimed in any preceding claim and further comprising means for enabling movement of said carriage means to be constrained within a chosen pattern.
10. A jig as claimed in claim 9 wherein said movement constraining means comprising a template fixable to the jig and a follower attached to the carriage and engagable with the template.
11. A jig as claimed in any one of claims 6, 7 or 8 wherein with the carriage held in a fixed position with respect to said first, second and third Cl pathes, the router can be used in the manner of a routing table, with workpieces being fed using a block of wood or the like clamped between the jaws of the work bench as a guide fence.
12. A jig substantially as herein described with reference to the accompanying drawings.