Abstract
A joint piece and jointing system using that joint piece are described. The invention is of particular value in making furniture which can be easily assembled and where the joints formed by joint pieces are visible only on the exterior of right-angled corners on one side of the exterior corner. Each joint piece (7) consists of a base having a protruding collar with a head. The base is circular or polygonal and fits into a recess made on one side of one of the panels (5) to be joined. Once fitted, the protruding collar and head fit into keyhole-shaped slots formed on the adjacent panel (6). An advantage of this jointing system is that the panels (5, 6) to be joined may all be produced by CNC milling from one side of a large original sheet of material, e.g. of wood or high density fibreboard.
Claims
1. A joint piece consisting of a circular or polygonal base having a generally cylindrical or prismatic structure and, protruding from one side of the base, in a direction perpendicular to the axis of the cylindrical or prismatic base a headed stud having a neck portion adjacent the base and, at the end of the neck portion remote from the base, a wider head, where the edge of the head is inset from the plane of one side of the base.
2. The joint piece according to claim 1 wherein the base is of generally triangular dovetail shape
3. The joint piece according to claim 1 wherein the sides of the base bear a relief surface.
4. The joint piece according to claim 3 wherein the relief surface is in the form of a set of ribs having an angled frusto-conical shape.
5. The joint piece according to claim 3 wherein the relief surface is relieved by a plurality of grooves running parallel to the axis of the cylindrical or prismatic structure of the base.
6. The joint piece according to claim 1 wherein the head of the headed stud is a dome shape.
7. The joint piece according to claim 6 wherein the head of the stud is relieved by one or more dimples.
8. The joint piece according to claim 1 wherein the neck portion of the stud is of cruciform cross-section.
9. A joint structure comprising two panels joined together using one or more joint pieces according to claim 1, wherein a first panel has, extending from a face of the panel, adjacent its edge, one or more recesses of a depth at least equal to the distance between the two faces of the base of the joint piece and of shape corresponding to the circular or polygonal shape of the joint piece base, the joint piece(s) being located in that recess, and the neck and head of the or each joint piece extends from the edge of the first panel and into a generally keyhole-shaped recess in a second panel, where the walls defining the narrower end of the keyhole shape in the second panel are undercut to provide a slot or seat into which the head of the stud forming part of the joint piece has been slid with the collar of the joint piece sliding along the narrower portion of the keyhole shaped slot.
10. The joint structure according to claim 9 where the length and position of the or each keyhole-shaped recess is such that when the joint is assembled with the stud(s) at the end(s) of the keyhole-shaped recess(es) the edges of the panels are aligned.
11. The joint structure according to claim 9 where the thickness of the panel material is such that the recesses into which the parts of the joint piece fit are blind.
Description
[0024] The invention is illustrated by way of example with reference to the accompanying drawings in which:
[0025] FIG. 1 shows various views identified as sub-FIGS. 1A to 1G of a first embodiment of a joint piece in accordance with the invention;
[0026] FIG. 2 shows various views identified as sub-FIGS. 2A to 2G of an alternative joint piece in accordance with the invention;
[0027] FIG. 3 is an exploded view of a corner structure showing a panel edge, two joint pieces and a second panel to be fixed to the first;
[0028] FIG. 4 shows the exploded view of FIG. 3 as viewed from the inside of the intended 90 joint corner formed by the assembled panels;
[0029] FIG. 5 is a diagrammatic view of the corner showing the two panels in full;
[0030] FIG. 6 (made up of sub-FIGS. 6A to 6G) shows a variant of the joint piece shown in FIG. 1;
[0031] FIG. 7 (made up of sub-FIGS. 7A to 7F) shows a panel clip in various views;
[0032] FIG. 8 shows in side view, side view at 90 to the first, section, end and perspective view, respectively FIGS. 8A to 8E, the structure of a headed stud which can be fixed to a panel and for engagement in an undercut keyhole slot in that panel.
[0033] FIG. 9 shows a simpler form of headed stud, sub-FIGS. 9A to 9D showing it respectively in section, side view, end view and perspective view;
[0034] FIG. 10 shows a modified form of the joint piece shown in FIG. 2;
[0035] FIG. 11 (made up of sub-FIGS. 11A to 11F) shows a further form of joint piece according to the invention;
[0036] FIG. 12 shows a double-headed stud which may be used to attach two panels together.
[0037] In each of FIGS. 1 and 2, sub-figures A and B show a plan and underneath plan view of the joint piece and sub-figures C, D, E and F show side views of the joint piece from four different sides. FIG. 1G is an isometric view of the joint piece. FIG. 2G is an enlarged section showing the detail of the circled part of FIG. 2C.
[0038] As can be seen in each case, the joint piece consists of a base 1 of generally triangular shape in the case of FIG. 1 and circular shape in the case of FIG. 2. Extending from the side is a neck 2 at the end of which is a head 3. The base has a cavity 8 in it to save on material.
[0039] As shown in FIGS. 1 and 2, the exterior surface of the base has a set of ribs 4 with an angled frusto-conical face which enable the joint piece to be held firmly once push-fitted into a generally triangular or circular recess made in the edge of a panel. The left-most rib 4 (as seen in FIGS. 1C and 2C) is inset from the triangular or circular base of the joint piece to assist in ensuring the joint piece can be accurately aligned when it is to be pushed into the recess in the panel. As shown, the triangular shape of base 1 in FIG. 1 has rounded corners which enables the triangular-shaped recesses in the panels to be made using a simple cylindrical milling tool.
[0040] The keyhole shapes in other panels may be made using a milling tool having a cutting head of shape corresponding to the stud formed by neck 2 and head 3 on each of the joint pieces.
[0041] Referring now to FIGS. 3 and 4, the two panels to be joined are denoted 5 and 6. Panel 5 has two generally triangular recesses milled adjacent one edge while panel 6 has two keyhole-shaped slots milled adjacent another edge. The two joint pieces denoted 7 are first press-fitted into the triangular recesses shown in panel 5 and panel 6 is then located so that the two round parts of the two keyhole-shaped slots register with the protruding studs of the joint pieces 7, and the two panels are then brought together so that the end of panel 5 lies adjacent the face of panel 6. Panel 5 is then moved in a plane parallel to the plane of panel 6 in the direction of arrow 8 so as to cause the heads of the joint pieces to move along the narrower portions of the keyhole slots. The positioning of the keyhole-shaped slots and of the triangular recesses is such that when the heads of the joint pieces 7 reach the ends of the undercut slots in panel 6, the top and bottom edges (as seen in FIGS. 3 and 4) of the two panels 5 and 6 lie in the same plane.
[0042] The final arrangement of the two panels and two joint pieces is shown diagrammatically in FIG. 5.
[0043] FIG. 6 shows a joint piece similar to that shown in FIG. 1, but with an alternative rib structure on the external generally prismatic base. It functions in the same way as the joint piece shown in FIG. 1.
[0044] In the clip piece shown in FIG. 7, the generally triangular base portion is similar to the base portion of the joint piece shown in FIG. 6, though of slightly lesser axial extent, but extending on the side of the prismatic base is a clip member consisting of a post extending in a direction perpendicular to the axis of the prismatic base and a tab denoted 10 running at a slight angle to the axis of the prismatic base so as to enable a thin panel to be supported at its edge with slight flexure of the post 9 so that the panel is gripped firmly. The panel is inserted in the direction of the arrow P shown in FIG. 7C.
[0045] If it is desired, in a furniture structure assembled using panels and joint pieces as described above and in accordance with the invention, to provide alternative undercut keyhole slots in one or more of the panels, this can be done with the object of receiving a headed stud, for example as shown in FIGS. 8 and 9. The stud shown in FIG. 9 of simple construction and intended to be mounted against the face of a panel. It has a central channel 30, the end of which is chamfered at 31 to receive the head of a standard wood screw.
[0046] The stud shown in FIG. 8 is used when it is desired to hold the stud in a pre-bored hole in a panel. Extending from a head portion 35 is a pair of legs 36 which together are adapted to be a press fit into a hole bored in the panel. The stud can be fixed in place by screwing a threaded screw through the head 35 and extending between the legs 36 to urge them firmly against the walls of the pre-bored hole.
[0047] FIG. 10 shows a developed form of the joint piece shown in FIG. 2, in which the configuration has been modified slightly to render the design more compatible with manufacture by injection-moulding.
[0048] In order to reduce the risk of distortion once the joint piece is extracted from the injection mould, as well as to reduce the amount of material used to make it, the head and sides of the stud are relieved, identified at 30 and 31 respectively on FIG. 10. Additionally, to assist fitting, a raised bead 32 is moulded on the side of the cylindrical section of the joint piece opposite the stud. A corresponding groove in the wall of the recess cut in the panel into which the joint piece is to be fitted may easily be provided using standard CNC milling techniques.
[0049] FIG. 11 shows a further developed form of the joint piece shown in FIG. 2. As can be seen, the joint piece has a stud portion 40 having its head and sides relieved at 41, 42 respectively for the same reasons as identified above with reference to FIG. 10. There is likewise a raised bead 43 on the side opposite the projecting stud to assist fitting into the cylindrical cavity formed in the panel with which the piece is to be used. In order to assist entry of the joint piece into the cavity in the panel, the edge 44 of the joint piece is chamfered. The ribs on the exterior surface of the base of the joint piece extend across the raised bead 43 and are themselves relieved by channels 45 which assist in enabling the sections of the ribs to flex as the joint piece is inserted into the preformed cavity in the panel.
[0050] Finally, the base of the stud portion 40 adjacent the body of the joint piece is reinforced by four wedge-shaped ribs 46.
[0051] FIG. 12 shows a double-headed stud, each end of which is of similar configuration to the stud portion of the joint piece shown in FIG. 10. The two heads are spaced apart by a distance which is double the distance from the side of a panel which has had an undercut keyhole shape formed in it and the surface of the undercut. These studs are used in order to fix two panels together, the two panels having keyhole-shaped undercut cavities in them of matching size, shape and positioning. The studs are first inserted into one of the panels and moved along to the end of the slot, whereafter the other panel is placed over the protruding studs, the heads of the protruding studs entering into the preformed keyhole-shaped configurations in the other panel, and the two panels, once they are touching, can then be slid one relative to the other to move the heads of the studs into the narrower end of the undercut keyhole shapes in the second panel. The two panels are accordingly fixed together, though they can be taken apart by sliding them relative to one another in the opposite sense.
