GB2238752A

GB2238752A - Dovetail joint formation

Info

Publication number: GB2238752A
Application number: GB9026499A
Authority: GB
Inventors: Edwin Bernard Froggatt
Original assignee: Individual
Current assignee: Individual
Priority date: 1989-12-06
Filing date: 1990-12-05
Publication date: 1991-06-12
Anticipated expiration: 2010-12-05
Also published as: GB9026499D0; GB8927579D0; GB2238752B

Abstract

Equipment for use in the production of a dovetail joint component includes a base (28) having a datum face (29) against which a component (30) to be machined is clamped. A pair of guide rails (33, 35) extend parallel to the datum face (29) and define a guided path along which a platform (27) can be moved. The platform (27) supports a template (10) and the template (10) has an aperture through which a routing cutter (62 or 76) can pass for engagement with the clamped component (30). <IMAGE>

Description

DOVETAIL JOINT FORMATION Field of the Invention This invention relates to the formation of dovetail joints such as are used in the manufacture of, for example, furniture drawers.

The present methods of producing dovetail joints, and the equipment which is currently available for the manufacture of dovetail joints, are not sufficiently versatile and have significant drawbacks which the present invention seeks to overcome, particularly by greatly reducing the setting-up time which is required. In this way, the equipment and method of the invention can be used as efficiently with one-off jobs as with longer production runs.

Summary of the Invention According to a first aspect of the present invention there is provided equipment for use in the production of a dovetail joint component comprising a router, a routing cutter, a base having a datum face against which a component to be machined can be clamped, means for supporting a template in a position fixed relative to the datum face, which template has an aperture through which the routing cutter can be passed for engagement with a clamped component and the boundary of said aperture defining a track along which the routing cutter is passed to effect the required machining operation.

According to a more specific aspect of the present invention there is provided equipment for use in the production of a dovetail joint component, which equipment includes a base having a datum face against which a component to be machined can be clamped, guide means extending parallel to said datum face, a platform carried by and movable along the guide means, means whereby a template can be releasably attached to the platform, the template having an aperture through which a routing cutter can be passed for engagement with a clamped component and the boundary of said aperture defining a track along which the routing cutter is passed to effect the required machining operation.

If the required machining operation involves the use of a parallel-sided routing cutter to produce a stopped dovetail, such as may be used in a drawer front, the aperture in the template will have a dovetail configuration. On the other hand, if the required machining operation involves the use of an angled cutter to produce a through dovetail, such as may be used in a drawer side, the aperture in the template will be parallel-sided.

Thus, according to a further aspect of the present invention there is provided a method of producing a dovetail joint component, which method involves clamping the component against a datum face of a base which includes guide means extending parallel to the datum face and a platform carried by and movable along the guide means, releasably attaching a template to the platform, which template has an aperture through which a routing cutter can be passed for engagement with the clamped component and the boundary of which aperture defines a track along which the routing cutter can be passed, selecting a routing cutter in dependence on the form of dovetail to be machined, and machining the component by moving the cutter along the track.

After the routing cutter has been moved completely around the track to machine the dovetail formation, the router is displaced and the platform is then advanced along the guide means by a measured distance corresponding to the spacing between adjacent dovetails in the component in preparation for a second or further machining operation to be carried out.

Other preferred features of the invention will be apparent from the following detailed description of one form of equipment which is illustrated in the accompanying drawings.

Brief Description of the Drawings Figure 1 is an end view of the equipment showing a piece of wood clamped in position in readiness for a machining operation to be carried out, Figures 2, 3, 4 and 5 are detail views of the equipment shown in Figure 1, Figure 6 is a front view of the equipment, Figure 7 is a plan view of a template for use in producing a through dovetail, Figure 8 is a plan view of a template for use in producing a stopped dovetail, Figure 9 is a plan view of a further form of template, Figure 10 is a side view illustrating the method of use of the template shown in Figure 9, Figures 11 and 12 are detail sectional views illustrating use of the template shown in Figure 9, Figure 13 is a detail view of part of the equipment shown in Figure 1, Figure 14 illustrates typical setting blocks for use with the equipment shown in Figure 1, and Figures 15 and 16 illustrate typical routing tools for use with the templates shown in Figures 7 and 8.

Description of the Preferred Embodiment Figures 7 and 8 illustrate adjustable templates which can be employed to produce dovetail formations. The template 10 shown in Figure 8 comprises a generally rectangular plate 11 which is formed with a centrally disposed, dovetail-shaped aperture 12 which has a pair of parallel sides 13 and 14 defined by bars 15 and 16, and a pair of opposed sides 17 and 18 equally and oppositely inclined at angles of 1000 to the parallel sides 13 and 14.

The inclined sides 17 and 18 are afforded by the facing edges of plates 19 and 20, plates 19 and 20 being adjustable towards and away from one another by means of screw adjusters 21 and 22. Each screw adjuster 21, 22 has a fine pitch to enable the inclined sides 17 and 18 of plates 19 and 20 to be moved into positions at selected spacings from one another.

The template 10 is intended, in use, to permit the production of a number of different sizes of dovetails, the angles between the inclined sides 17 and 18 being such as to produce dovetail slots which have opposed angles of 1000. The spacing between the sides 17 and 18 can be set using a series of setting blocks 23, 24, 25 and 26 shown in Figure 14. The setting blocks 23, 24, 25 and 26 are of different dimensions corresponding to the different dimensions of the dovetail slots which are to be formed.

In practice, fourteen or more setting blocks may be provided for cutting twenty six or more stopped or through dovetails with template 10 in a fixed position on platform 27 relative to a datum face 29. Alternatively, template 10 may be adjusted by the means variously described to produce widely varying sizes of dovetail configurations.

The setting blocks will be appropriately secured together on, for example, a chain. The user of the equipment, who wishes to produce dovetail slots of a given size, will chose the required setting block, place it between the plates 19 and 20 and move the plates together by means of the screw adjusters 21 and 22 into contact with the block.

For some cabinet work, however, dovetails with opposed angles of 1050 are preferred. In such instances, an alternative template or converting piece (not shown) will be used which corresponds to that shown in Figure 8 but in which the sides 17 and 18 are inclined at angles of 1050 to the parallel sides 13 and 14.

The template 10 is mounted on a platform 27 (see Figures 1 and 6), the platform 27 being movable relative to a base 28 which has a datum face 29 against which a piece of wood 30 which is to be machined is clamped. The platform 27 carries a first pair of rollers 31 and 32 which engage a guide rail assembly 33 fixed to the base 28. A support bracket 34 (see Figure 13) is provided at each end of the base 28, the two support brackets carrying, between them, a second guide rail assembly 35. The platform 27 being provided with a second pair of rollers 36 which rest on the rail assembly so that fourpoint support for the platform 27 is provided.

A screw adjustment mechanism 37 extends between the two brackets 34 parallel to the two rail assemblies 33 and 35 and the platform 27 is movable longitudinally of rail assemblies 33 and 35 by operation of mechanism 37 by means of a handle 38 shown in outline in Figure 13. The longitudinal position of the platform 27 relative to the screw 37 may be indicated by a revolution counter (not shown).

For some machining operations, it may be desirable to hold the platform 27 against movement upwardly relative to the base 28. In such cases, a further guide assembly 41 (see particularly Figure 4) is utilised. The guide assembly 41 is fitted releasably in a socket in the platform 27 and is held in position by means of a locking screw 42. The assembly 41 includes a stem 43 at the lower end of which a roller 44 is provided. This roller 44 engages beneath the second guide rail assembly 35 (as shown in Figure 1) and prevents inadvertent upward movement of the platform 27 such as might occur, for example, when a dovetail-shaped routing cutter is being used.

The template 10 includes a pair of downwardly projecting pegs 45 and 46 which engage in sockets in a slide block 47 arranged for sliding movement in a channel formed in the platform 27. The channel in which the slide block 47 is received extends at right angles to the axes of the guide rail assemblies 33 and 35, movement of the slide block 47 along the channel being effected by means of a screw adjustment mechanism 48 which includes a knurled wheel 49 rotation of which serves to effect rotation of a shaft 50 which has threaded engagement with the slide block 47.

When the wheel 49 is turned the position of the template 10 in the direction at right angles to the rail assemblies 33 and 35 is adjusted, the position of the template 10 being indicated by means of an indicator, such as that shown in Figure 5, which includes a pointer 39 movable over a scale 40.

For convenience, the screw adjusters 21 and 22 which form part of the template 10 are shown in Figure 6, but the screw adjustment mechanism 48 for moving the template 10 is not shown in Figure 6. As shown in Figure 6, the template 10 is secured to the platform 27 by fasteners 51 and 52, the method of attachment of the template 10 being such as to permit limited movement of the template 10 relative to the platform by said screw mechanism 48.

After the component 30 has been clamped against the face 29 of the base 28, the template 10 is set in the required position both longitudinally and transversely of the slideway assembly afforded by the guide rails 33 and 35. Clamping of the component 30 is effected by means of a clamp member 53 which is urged into clamping engagement with the component 30 by first tightening a nut 54, which has threaded engagement with a rod 55, and then turning a threaded rod 56 which bears against the lower portion of the base 28. The rod 55 is fixed to a plate 57 attached to the base 28.

In order to ensure that the component 30 is clamped in position at the right height, a pair of height control elements 58 are provided, one adjacent each end of the component 30. As shown in Figure 3, each such element 58 includes a horizontal limb 59 against the lower face of which the upper surface of the component 30 is positioned. A guide 60 is attached to the upper portion of the base 28 and each element 58 is formed with a channel 61 so that it can be slid into position along the guide 60. When not required, the elements 58 can be slid to the ends of the guide 60 out of the way.

After the component 30 has been clamped and the platform 28 and template 10 have been set in the required positions, the machining operation is carried out using a routing tool. The routing tool includes a housing within which an electric motor is housed, the electric motor having an output shaft to which a straight, parallel-sided cutter 62 (as shown in Figure 15) is attached. The cutter 62 projects downwardly through an opening in a guide sleeve fixed to a cover plate which is located beneath the housing and is spring-loaded away from the housing so that it normally acts as a cover and protector. for the routing cutter 62.

In carrying out a machining operation, the routing tool is moved downwardly so that the cutter 62 passes through the opening 12 in the template 10 and this downward movement is continued until the cover plate has been moved back against the action of the spring to its fullest extent by contact with the template 10 and then locked in position. The guide sleeve is moved into engagement with one of the sides of the opening 12 and is then moved completely along each of the sides of the opening 12 in turn so that the whole of the dovetail slot formation is machined.

After a first dovetail slot has been machined in the component by the method described above, the routing cutter is displaced rearwardly out of engagement with the component 30 and the platform is moved along the slideway by rotation of the handle 38 through a specified number of revolutions. This will advance the template 10 a given distance relative to the component 30 in readiness for the machining of the next dovetail slot in just the same way as has been described above.

It should be appreciated that any number of dovetails can be machined in a single component, the platform 27 being moved relative to the base 28 between successive machining operations and then located in position as determined by, for example, the reading of the revolution counter.

The platform 27 may be in the form of an aluminium block which is appropriately drilled and tapped. It may also be drilled and reamed to receive hardened steel bushes.

Turning next to Figure 7, this shows the use of a tailadjustable template 70 instead of the pin-adjustable template 10 shown in Figure 8. The template 70 can be fastened to the platform 27 in just the same way as the template 10 and differs therefrom in the configuration of the opening 71 which is of rectangular configuration as shown. The width of the opening 71 is adjusted by means of a sliding plate 72 which is moved by means of a fine pitch screw adjuster 73 operated by a knurled knob 74. The plate 72 has its edges received in guide channels formed in a pair of guide strips 75 so that guided sliding movement of the plate 72 can be effected.

The template 70 is used in a similar manner to the template 10 except that a dovetail form routing cutter 76 is used as illustrated in Figure 16. After the component to be machined has been clamped in position, and the platform 27 moved into position, the routing tool is lowered to commence the machining of the dovetail slot. The cutter 76 is moved so that the cutter guide passes along each side of the rectangular opening 71 in the template 70.

An important feature of the present invention is that, merely by providing a choice of two templates, a whole range of different configuration dovetail slots can be machined. The dovetail slots can be produced efficiently and accurately using relatively inexpensive equipment.

Referring next to Figures 9 to 12, these show the use of an alternative form of template construction to form other types of dovetails, particularly parallel and tapered dovetail housing joints.

As shown in Figures 10 and 11, a flat base plate 80 acts as a support surface on which a component 81 to be machined can be placed. A template 82 is fixed in position on top of the component 81, the template 82 being provided at its edges with angle-section bars 83 so that, by fasteners 84, the bars 83 are secured to flanges 85 of the base 80. The template 82 includes a flat rectangular plate 86 which is slidable over the main body 87 which is formed with a rectangular aperture 88. The ends of the plate 86 are received in guide channels afforded by guide strips 89 and 90, and the plate 86 is arranged for sliding movement by means of a pair of screw adjustment mechanisms 91 and 92.

The sides of the aperture 88 afford guide surfaces which, as illustrated in Figure 11, are engaged by the cutter guide 93 of a routing tool 94 which includes a cover plate 95 which bears against the upper surface of the template 82. The routing tool has a dovetail-shaped routing cutter 96 so that, as the routing cutter 96 is moved along the edges of the aperture 88 in the template 82, a dovetail slot is formed in the component 81.

Figure 12 illustrates a method of machining an edge of a wooden component 97 so as to provide a dovetail-shaped edge on said component 97 for fitment in the dovetail slot formed in the component shown in Figure 11. As shown in Figure 12, a base 98 includes a pair of angle-section elements 99 and 100 between which are located a pair of clamping plates or strips 101 and 102. A template 103 is attached to the base 98 so that the component 97 to be machined is located beneath a pair of apertures formed in the template 103.

The apertures in the template 103 are elongated rectangular apertures and each aperture affords a guide surface along which a dovetail-shaped routing cutter can be moved so as to machine the edges of the component 97. The apertures in the template 103 can be defined by adjustable sliding plates in the manner described above, the positions of the sliding plates being set by means of screw adjustment mechanisms (not shown) in dependence on the thickness of the component 97 and the thickness of the dovetail required at the edge of the component 97.

Claims

Claims:

1. Equipment for use in the production of a dovetail joint component comprising a router, a routing cutter, a base having a datum face against which a component to be machined can be clamped, means for supporting a template in a position fixed relative to the datum face, which template has an aperture through which the routing cutter can be passed for engagement with a clamped component and the boundary of said aperture defining a track along which the routing cutter is passed to effect the required machining operation.

2. Equipment for use in the production of a dovetail joint component, which equipment includes a base having a datum face against which a component to be machined can be clamped, guide means extending parallel to said datum face, a platform carried by and movable along the guide means, means whereby a template can be releasably attached to the platform, the template having an aperture through which a routing cutter can be passed for engagement with a clamped component and the boundary of said aperture defining a track along which the routing cutter is passed to effect the required machining operation.

3. Equipment according to Claim 2, in which the routing cutter is a parallel-sided routing cutter which is used to produce a stopped dovetail, such as may be used in a drawer front, and in which the aperture in the template has a dovetail configuration.

4. Equipment according to Claim 2, in which the routing cutter is an angled cutter which is used to produce a through dovetail, such as may be used in a drawer side, and in which the aperture in the template is parallel-sided.

5. Equipment as claimed in Claim 2, Claim 3 or Claim 4, in which means are provided for effecting controlled movement of the template relative to the platform in a direction at right angles to the direction of movement of the platform relative to the base.

6. Equipment as claimed in Claim 5, in which the base carries a pair of spaced guide rails and the platform includes wheels which engage on said guide rails and a wheel which engages under one of the guide rails.

7. A method of producing a dovetail joint component, which method involves clamping the component against a datum face of a base which includes guide means extending parallel to the datum face and a platform carried by and movable along the guide means, releasably attaching a template to the platform, which template has an aperture through which a routing cutter can be passed for engagement with the clamped component and the boundary of which aperture defines a track along which the routing cutter can be passed, selecting a routing cutter in dependence on the form of dovetail to be machined, and machining the component by moving the cutter along the track.

8. A method according to Claim 7, in which, after the routing cutter has been moved completely around the track to machine the dovetail formation, the router is displaced and the platform is then advanced along the guide means by a measured distance corresponding to the spacing between adjacent dovetails in the component in preparation for a second or further machining operation to be carried out.

9. A method of producing a dovetail joint component as claimed in Claim 7 or Claim 8 and substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

10. Equipment for use in the production of a dovetail joint component substantially as hereinbefore described with reference to and as shown in Figures 1 to 8, 13 and 14 of the accompanying drawings.

11. Equipment for use in the production of a dovetail joint component substantially as hereinbefore described with reference to and as shown in Figures 9 to 12 of the accompanying drawings.