GB2087792A

GB2087792A - Profiling discs for woodworking machinery

Info

Publication number: GB2087792A
Application number: GB8037817A
Authority: GB
Original assignee: WADKIN Ltd
Current assignee: WADKIN Ltd
Priority date: 1980-11-25
Filing date: 1980-11-25
Publication date: 1982-06-03
Also published as: FR2494622A1; GB2087792B; DE8134244U1; FR2494622B1

Abstract

An annular metal disc has formed therein a number of peripheral recesses 3 each receiving a wedge 10 and a blade element 14, wherein the rearwardly facing face of each blade element is serrated axially of the disc to cooperate with corresponding serrations in the cooperating wall 6 of the recess; and a groove in the rearwardly facing face of each blade element receives a Woodruff key 9. The key, securely located in a cut-out portion of the above serrated wall of the recess, serves the dual function of locating each blade accurately mid-way of the disc during assembly and in use. <IMAGE>

Description

SPECIFICATION Profiling discs for woodworking machinery This invention relates to profiling discs for woodworking machinery. A profiling disc is a rotary cutter having peripheral knife blades when rotated against a timer workpiece, cut away some of the timber. The most common form of profiling disc is a tenoning disc which cuts the timber so as to leave a tongue or tenon. Howeverthe invention also relates to other profiling discs, principally for use in furniture manufacture, which permits the production of more complex profiles. The latter discs must always be top ground,that isto say the blades must be ground in a direction from the radially outermost edge of the blade, to produce the necessary profiles.All such profiling discs are necessarily quite thin, often 8 mm or less, and the discs rotate at very high speeds in use so that the need for a secure mounting of the blades on the disc is paramount.

It has been proposed to secure the blades to the disc by means of bolts parallel to the axis of the disc, passing through overlapping portions of the blade and the disc. Such a construction is not wholly satisfactory in practice, as the portions of the blades relative to the disc are fixed by the respective bolt holes, so that there is no possibility for blade adjustment after grinding. Such discs are, nevertheless, in widespread use.

Another proposal is for the blades to be clamped onto the disc by a wedging action. One suggestion has been for the blade itself to have a series of axial serrations for mating with corresponding serrations in a backing area of the disc, and to have the wedge provided with a series of radial serrations for cooperating with corresponding serrations in a reaction surface of the disc. The two mutually perpendicular serrations serve positively to locate both the wedge and the blade in the disc, and prevent the blade from becoming displaced during use. This method of mounting does allow the blade to be moved radially of the disc before tightening the wedge, but only a limited amount of movement is permitted before the cooperating surfaces of the blade and disc are insufficient effectively to secure the blade in the disc.This method of mounting the blades enables the disc width to be reduced to about 5 mm, as opposed to 8 mm for the bolt-on blade mounting discussed above.

There is a need for an even more secure mounting of the blade, that is sufficiently robust to allow the blade to be moved relative to the disc for much longer distances so that the blade can be repeatedly re-ground a very substantial number of times before requiring replacement.

This invention accordingly provides a profiling disc comprising an annular metal disc having formed therein a number of outwardly facing peripheral recesses each containing a blade element wedged therein by a wedge member, wherein of a forwardly facing rear surface of each recess and the rear face of each blade element, both are formed with mating serrations extending parallel to the disc axis, one is formed with a keyway extending radially of the disc perpendicular to the serrations, and the other is formed with a cut-out portion that contains a key member spanning the disc and the blade element for locating the blade element in the plane of the disc, advantageously centrally of the disc. The key member is preferably a Woodruff key that is secured in an arcuate cut-out portion ground into the forwardly facing rear surface of the recess.The securing of the Woodruff key may be by adhesive, or it may be a force fit.

The location of the blade element that is obtained according to the invention by the mutually perpendicular serrations and key is very precise, and superior to any form of blade mounting previously proposed.

Lateral movement of the blade element relative to the disc, permitted in the prior art wedge mounting discussed above, is completely prevented in the profiling disc according to the invention by the use of the key member. Also, twisting of the blade relative to the disc is prevented by the key member, but axial sliding of the blade elements outwardly of the disc for regrinding purposes is readily achieved.

The serrations in the blade element and disc have the duai function of increasing the security of the blade in the disc during use, and, when the wedge is loosened to permit movement of the blade element relative to the disc, of enabling the blade elements to be indexed outwardly notch by notch so that diametrically opposite blade elements can be maintained accurately in balance.

The ability to keep the blade elements acurately in balance can be maintained throughout a large extent of blade movement so that the blades can be moved outwardly of the disc for a large number of increments, corresponding to a large number of regrinding operations, before they eventually have to be replaced.

The wedge members that secure the blades in the recesses preferably have radial serrations on one or both of their faces corresponding with mating serrations in the facing surfaces of the disc and/or the blade element. Such serrations permit the radial sliding of the wedge elements that is necessary to obtain a good wedging action, while maintaining the wedge elements securely in the plane of the disc.

Drawings Figure 1 is a side elevation, partly in section, of a tensioning disc according to the invention with only one of its four blade elements wedged into position; Figure2 is a section along the line X - X of Figure 1; Figure 3 is a side elevation of a wedge of the disc of Figure 1; Figure 4 is a top view of the wedge of Figure 3; Figure 5 is a side elevation of a blade element of Figure 1; Figure 6 is a top view of the blade element of Figure 5; and Figure 7 is a rear view of the blade element of Figure 5.

The tenoning disc of Figure 1 comprises an annular metal disc 1 having a circular central mounting aperture 2 for mounting the disc on a drive spindle (not shown). Around the periphery of the disc 1 are four equally spaced outwardly facing recesses 3 each of which is divergent when viewed in a direction from the periphery of the disc inwards.

A run-in section to each recess 3 is formed by machining a flat 4 chordally of the disc 1. This flat 4 is to the front of the recess 4 as viewed in the intended direction of rotation of the disc as indicated by the arrow A.

A rearwardly facing front face 5 of each recess 3 is formed with a series of radial serrations, each parallel to the plane of the disc 1, as most clearly seen in Figure 2. A forwardly facing rear face 6 of each recess 3 is provided with a series of serrations parallel to the axis of the disc 1. Cut into the face 6 is an arcuate slot 8 located centrally between the opposite side faces of the disc 1, and cemented into the slot 8 is a Woodruff key 9.

A wedge 10 has a front face 11 serrated (see Figures 3 and 4) to cooperate with the serrated face 5 of each recess 3, and has a screw threaded bore 12 receiving a clamping screw 13 for clamping the wedge into the recess 3 between the serrated face 5 and a blade element 14.

Each blade element 14 has a serrated rear face 15 for cooperating with the serrations of the rear face 6 of the groove 3, and has a longitudinal slot 16 formed therein centrally of the rear face 15, perpendicularto the serrations. The slot 16 is dimensioned to receive the Woodruff key.

In use the disc 1, wedges 10 and blade elements 14 are assembled as shown and the clamping screws 13 tightened to clamp the blade elements firmly in place. The Woodruff keys have the dual function of locating the blades accurately mid-way of the disc 1 and maintaining them in use in the plane of the disc (and hence in the same plane as each other) even though repeated impacts may attempt to dislodge them from a true coplanar setting.

Repeated regrinding of the blades 14 is possible and is achieved by grinding from the top face 17 of the blades. The cooperating serrations in the faces 6 and 15 enable the blades 14 to be advanced from the recesses 3 incrementally while maintaining the balance of the assembly, and the stability provided by the Woodruff key 9 increases the extent to which the blades may be advanced from the recesses in use. Afurther extension of blade life is provided by forming each recess 3 with a deeper well portion 18 for receiving the base of a new blade 14. As the blade is repeatedly reground and advanced from the recess 3, so the base of the blade is raised out of the well portion 18, which therefore defines an increase in the number of blade regrinding operations that could otherwise be achieved.

Claims

1. A profiling disc comprising an annular metal disc having formed therein a number of outwardly facing peripheral recesses each containing a blade element wedged therein by a wedge member, wherein of a forwardly facing rear surface of each recess and the rear face of each blade element, both are formed with mating serrations extending parallel to the disc axis, one is formed with a keyway extending radially of the disc perpendicular to the serrations and the other is formed with a cut-out portion containing a key member spanning the disc and the blade element for locating the blade element in the plane of the disc.

2. A profiling disc according to claim 1, wherein each keyway is formed in the rear surface of the blade element and each key is located in its cut-out portion in the rear face of the peripheral recess in the disc.

3. A profiling disc according to claim 2 wherein the keys are located in a common plane midway between the opposite sides of the annular metal disc.

4. A profiling disc according to any preceding claim, wherein the keys are Woodruff keys contained in arcuate cut-out portions of the disc.

5. A profiling disc according to any preceding claim, wherein a rearwardly facing front surface of each recess and a front surface of each wedge member are formed with cooperating serrations extending parallel to the plane of the disc for locating the wedge members in the plane of the disc.

6. Atenoning disc substantially as described herein with reference to the drawings.