IMPROVEMENT IN A JOINT BETWEEN PLATE-SHAPED ELEMENTS

Abstract: The invention provides a plate (10) being slotted to at least half the plate height, the plate on each face (11,12) being provided with a groove (21,22). The edges of the slot (17) and of the grooves are bevelled at an angle of 45°, such that the bevels (23,24,25,26) extend down to the bottoms (27,28) of the grooves and such that the material of the plate remaining between the bottoms of the grooves and the free opening of the slot (17) have equal square cross-section.

Description: IMPROVEMENT IN A JOINT BETWEEN PLATE-SHAPED ELEMENTS. The present invention concerns a plate-shaped element, which for its assembly with at least one similar plate -shaped element is provided with at least one slot extending from one edge of the element to at least half the height of the element and continuing on both faces of the element with a groove extending to the opposite edge of the element. The invention also concerns a joint obtained at assembly of two elements of the above mentioned kind, as well as a product assembled of at least two elements of the kind mentioned. Two plate-shaped elements of the kind mentioned may be joined generally in a right angle cross-shape to form e.g. a table support, the elements being interengaged such that the slot of one element grips around the other element in its opposed grooves. Contrary to the most simple form of joint between two plate-shaped elements, where each element only has a slot, the form just mentioned ascertains that the plate portions on each side of the slot obtain guidance by the sides of the groove of the other element, as may be desirable when weak plate materials are being utilized. A joint substantially embodying this principle is described in U.S. Patent Specification No 4 084 517. It is, however, necessary that the plate material holds accurate tolerances of thickness, so that a groove of one element, which groove has been made for a certain nominal thickness of a co-operating element, preferably shall not be too wide and absolutely not too narrow. Since the tolerances of thickness of plate materials available on the market, preferably organical glass, such as a polyacrylate, e.g. the one sold under the trade name PLEXIGLAS, that are suitable for the manufacture of e.g. table supports, do not keep sufficiently accurate tolerances, one object of the invention is to provide a plate-shaped element of the kind initially indicated, which is apt to be joined together with a similar element, without any tolerance requirements need be met as concerns the element thickness. Another object of the invention is to provide a joint between plate-shaped elements, by which is achieved a better mutual guidance between the elements. A further object of the invention is to provide a product assembled from at least two plate-shaped elements, which product is well suited as a support for e.g. table tops. These objects have been achieved in that the invention has been given the characteristics of the annexed claims. According to the invention, thus, the edges of the slot as well as those of the grooves connected to the element faces, are continuously bevelled at an angle of 450 so that the bevels extends down to bottoms of the grooves and so that the plate material remaining between the bottoms of the grooves as well as the free opening of the slot have an equal square cross section. By this arrangement not only all variations in thickness loose their practical importance to the possibility of obtaining a joint between two plate-shaped elements, but one can even intentionally and at one's discretion assemble plate-shaped elements having different nominal thickness provided both elements have equal square cross section between their groove bottoms and in their free slot openings. British Patent Specification 1 421 535 shows various embodiments of a furniture support constituted by two H-shaped welded tubular frames that are joined together in a way similar to that of plate-shaped elements according to the invention. Hereby linear contact is obtained between adjacent tubes, and for co-operation with a certain tubular frame will fit only other certain tubular frame dimensioned for that purpose. At a joint between two plate -shaped elements according to the invention, on the contrary, surface contact is obtained between the bevelled groove and slot sides, respectively, which means an advantageous mutual guidance between the elements and good firmness to the assembled product, and, under the aforementioned condition any plate-shaped elements according to the invention can be assembled. The invention will now be described under reference to the accompanying drawing, wherein Fig. 1 shows a perspective view of an example of a plate -shaped element according to the invention; Fig. 2 shows a joint between two plate-shaped elements according to the invention as seen along the grooves and slot, respectively, of the elements; and Fig. 3 shows a perspective view of a product according to the invention assembled from two plate-shaped elements according to the invention. The plate-shaped element shown in Fig. 1 is a rectangular plate 10 having two opposed side faces 11 and 12, two mutually parallel edges 13 and 14, and two likewise mutually parallel side edges 15 and 16. Perpendicularly from the upper edge 13 according to Fig. 1 a slot 17 extens through the plate 10, the nominal thickness of which is t (see Fig.2), said slot being directed towards the bottom edge 14 and reaches at least half the plate height as counted from above. The slot 17 has parallel sides 18 and 19 and a bottom surface 20 perpendicular thereto. The width of the slot, i.e. the distance between its sides 18 and 19, is a (see Fig. 2). In the side faces 11 and 12 of the plate are further opened twoopposedgrooves 21 and 22 joining the slot 17 and extending between the edges 13 and 14. According to the invention the sides 23 and 24 of the groove 21 and the sides 25 and 26 of the groove 22 are bevelled at an angle of 450 against the side faces 11 and 12 (see Fig. 2). The grooves are so deep that the remaining plate cross section, e.g. the bottom surface 20 of the slot 17, between the bottoms 27 and 28 of the grooves 21 and 22, respectively, as well as the cross section of the free opening of the slot 17, is square with the side a (see Fig. 2), i.e. equal to the width of the slot. In Fig. 2 are shown two equal plates 10 and 10' according to the invention being assembled so that the respective square slot bottoms 20 abut or at least face each other. As is clearly apparent there is surface contact between the.groove sides of the plate along diagonal surfaces of contact (the visible interspaces have been drawn merely to make the individual plates discernible). Likewise it should clearly appear that e.g. a plate 10 having the nominal thickness t without anything further lets itself be assembled with a plate 10", the outlines of which are drawn with dash-dotted lines and the thickness of which is tl, while still the cross section between its groove bottoms have the thickness and the width a. Through the invention, thus, has been created a possibility to provide joints not only between plate-shaped elements having large tolerances of thickness, but also between plate-shaped elements having widely different nominal thicknesses. In Fig. 3 finally, are shown two plates 10 and 10' according to the invention being assembled to a product that, e.g., is suitable as a table support. With a square slot bottom is here also meant the case when the slot 17 is opened with a cylindrical cutter and, thus, the slot bottom 20 has a semi-cylindrical shape, but still a square projection.

Claims: WHAT I CLAIM IS: 1. A plate-shaped element, which for its assembly with at least one similar plate-shaped element is provided with at least one slot (17) extending from one edge (13) of the element (10) to at least half the height of the element and continuing on both faces (11,12) of the element with a groove (21,22) extending to the opposite edge (14) of the element, c h a r a c t e r i z e d i n that the edges of the slot (17) and of the grooves (21,22) connected to the element faces (11,12) are continuously bevelled at an angle of 450, so that the bevels (23,24,25,26) extend down to the bottoms (27,28) of the grooves and so that the material of the element remaining therebetween and the free opening of the slot (17) have an equal square crosssection. 2. A joint between two plate-shaped elements (10,10'), which both have slots (17) extending to at least half the element height and grooves (21,22) connected to the slots and extending over the entire element heights, said elements being interengaged such that the bottoms (20) of the slots face each other, c h a r a c t e r i z e d i n that the bottoms (20) of the slots face each other with equal square surfaces and that contact between the grooves takes place along surfaces (23,24,25,26) of contact being diagonal in respect of the square surfaces. 3. A product comprising at least two plate-shaped cross -wise assembled elements (10,10'), wherein each element is pro vises with a slot (17) extending to at least half the element height and on each element face (11,12) a groove (21,22) connected to the slot and extending over the entire element height, c h a r a c t e r i z e d i n that the bottoms (20) of the slots (17) face each other with equal square surfaces and that the elements for the rest contact each other over the entire element height along surfaces (23,24, 25,26) of contact being diagonally directed in respect of the square surfaces.

Inventors: FRITZELL, LARS
Applicants: ABG TRADING AB
Application year: 1983
Main classification: F16B12
IPC codes: F16B12