Joining

This invention relates to the joining of members together. As will become clear from the description which follows, embodiments of coupling means constructed in accordance with this invention are particularly useful for interconnecting panels in the furniture industry, although the invention is also of wider utility.

Nowadays the trend in the furniture industry is towards so-called "quick-assembly" or "knock-down" furniture (hereafter referred to as "KD furniture"). KD furniture is manufactured as a number of components adapted for ready assembly (and frequently also for ready disassembly) by the retailer or purchaser. As compared with traditional furniture, KD furniture has two great advantages. Firstly, it can be transported and sold in flat packs which take up relatively little space. Consequently transporting and warehousing costs are substantially reduced. Because the furniture takes up so little space, a retailer can readily keep stocks of KD furniture in its flat packs in his furniture store so that the customer can take away his purchase immediately. Surveys have shown that the purchasing of furniture is frequently by impulse and a customer is severely disappointed if, as frequently happens with traditionally manufactured furniture, to obtain the furniture which he sees on display he must wait weeks and often months for delivery.

The principles of KD furniture design can be applied to most kinds of furniture. A new type of furniture which makes best use of the principles of KD furniture design is so-called "systems furniture". Systems furniture consists of relatively small components which can be coupled together by the purchaser in various combinations to provide him with different eventual shapes and configurations for his furniture. Moreover, the design of the system can be altered either by re-arrangement or by addition of further components. Systems furniture is often assembled from flat panels of various sizes and coupling means for assembling the panels together.

Since the items of KD or systems furniture may be assembled by a relatively unsophisticated purchaser, the coupling means employed should be both reliable and relatively easy to use. A number of different forms of coupling means have been previously proposed. We have not found any heretofore which is in our view entirely satisfactory. It is frequently difficult to ensure precise alignment of apertures for connecting parts. Manufacture of furniture components to close tolerances would make them uneconomically expensive. It is thus highly desirable in our view for the coupling components to be at least to some extent self locating.

In accordance with one aspect of the present invention, we provide coupling means, comprising: a body member having a threaded opening which communicates with an internal cavity; an elongate headed member, a shank portion of which is receivable through a slot formed in the side of the body member with its head retained within the cavity; and a threaded member receivable in the threaded opening and adapted to bear against the head of the headed member, the interior of the cavity being so shaped that tightening of the threaded member in the opening is arranged to draw the shank of the headed member further through the slot into the interior of the cavity.

Preferably, the interior of the cavity is formed with a sloped internal surface (and preferably a frustoconical internal surface) adjacent the slot and along which the head of the headed member may slide or cam as the threaded member is tightened in the threaded opening.

When the coupling means is to be used to interconnect two flat panels in KD or systems furniture, each panel may be formed with a through bore in a region adjacent an edge and with a passage at right angles to the through bore and opening in the through bore and at the said edge of the panel. The headed member is inserted through the passageway head first from the edge of the panel. Suitably its extreme shank end is formed with a threaded portion for connecting the headed member to a connecting block or rod suitably square in cross section each side being generally of the same width as the panel and the connecting rod being formed with through bores at right angles to each other for receiving the respective threaded shank ends of headed members. With the headed member extending into the through bore in the panel, the body member is pushed into the through bore so that the sides of the slot embrace the shank of the headed member and so that the head of the headed member lies within the cavity. If the threaded member is then inserted into the through bore from the other side into engagement with the threaded opening of the body member and is tightened, the headed member may be drawn further into the cavity to bring the connecting rod into firm engagement with the edge of the panel. A second panel may be similarly connected to the connecting rod on another side thereof. In this way a whole system may be interconnected.

Embodiments of coupling means in accordance with this invention may be utilised in other ways. For example a panel or first structural element may be coupled to a second structural element if the first element is provided with a through bore in which the body member is received and also with a passage opening into the through bore at right angles to its axis and also opening at an external surface of the first element. The shank end of the headed member is received in the second structural element (which may for example be provided with a threaded socket for receiving a threaded end of the headed member; alternatively, the headed member way be fixedly joined to the second element as by glue) so that the headed member extends outwardly from the second element and may be received through the passage such that its head extends into the through bore so that the body member may be pushed into the through bore so that the sides of its slot embrace the shank of the headed member with the headed member retained within the cavity of the body member, all as before.

FIG. 1 shows a body member of an embodiment of coupling means constructed in accordance with this invention in plan.

FIG. 2 shows an axial sectional view of the body member of FIG. 1 taken along the line II--II.

FIG. 3 is a side elevational view of a headed member of an embodiment of coupling means in accordance with the present invention.

FIG. 4 is a side elevational view mostly in section showing the manner of use of an embodiment of coupling means in accordance with the present invention.

FIG. 5 shows a view generally similar to FIG. 3 of a back location pin useful in an embodiment of systems furniture in which the principal components are interconnected by means of an embodiment of coupling means of the kind shown in FIG. 4.

As is clear from FIGS. 1 and 2, the body member 1 is formed from a generally cylindrical body of material the ends of which are bevelled slightly, as at 3 to aid insertion of the body member into a through bore, such as 3, formed in a panel such as 4 (see FIG. 4). Body member 1 has a threaded opening 5 which communicates with an internal cavity 6, which as shown has a frustoconical internal wall 7. The side wall of the body member is provided with a slot 8. The end of body member 1 opposite threaded opening 5 may also be open as at 9. This opening may also be threaded.

The elongate headed member 10 shown in FIG. 3 has a threaded portion 11 at the end of the shank opposite to the head 12. Apart from a reduced diameter portion 13, the shank 14 may have the same external diameter as the head 12.

Reference may now be made to FIG. 4 which illustrates one application of an embodiment of coupling means constructed in accordance with the present invention. It will be noted that both the body member and the headed member of the coupling means of FIG. 4 differ slightly in configuration from those illustrated in FIGS. 1 to 3. For convenience like reference numerals are used for the like parts in the different figures.

FIG. 4 is not intended to depict a portion of furniture joined by means of an embodiment of coupling means. Instead, the figure is intended to illustrate ways in which the coupling means may be employed.

Attention is first directed to a connecting block or rod 15 suitably square in cross section, as here shown, each side being of the same width as the panel 4. The connecting rod 15 is formed with through bores 16 and 17 at right angles to each other and may be formed with similar through bores at intervals along its length. Each of the through bores is threaded for receiving the respective threaded end portion 11 of a headed member 10. In order to connect rod 15 to the edge 18 of a panel such as 4, the threaded end 11 of a headed member 10 is first threaded into a bore such as 17, as illustrated. Head 12' is then inserted into a passage 19 which extends at right angles to the through bore 13 in panel 4 and opens in the said through bore at the edge 18 of the panel. With headed end 12' of member 10 extending into through bore 3, a body member 1 is pushed into the through bore so that the sides of its slot 8 embrace the reduced diameter portion 13 of shank 14 of the headed member. A threaded member 20 is inserted into threaded opening 5 of body member 1 and tightened. In so doing, it will come into contact with head 12' which is retained within the cavity 6 of body member 1. As a result, head 12' slides or cams along the sloping internal wall 7 (here frustoconical) of the cavity under the continuing tightening pressure of threaded member 20 there-against. In practice, since shank 14 is retained in side passage 19 to the through bore 3, it is the body member 1 which actually slides within its through bore. The slope of wall 7 causes the headed member to be drawn further along passage 19 of through bore slot 8 into cavity 6 resulting in firm engagement of connecting rod 15 with edge 18 of the panel.

If this procedure is repeated with insertion of the shank end 11 of a similar headed member 10 into bore 16 of connecting rod 15, a similar panel may be joined to connecting rod 15 at right angles to the first panel. By repeating this procedure, an embodiment of systems furniture may be built up. The furniture can be readily disassembled simply by withdrawing the threaded member 20 and pushing body member 1 over head 12' of headed member 10 and out of its through bore 3 so that the headed member 10 can be withdrawn through bore passage 19.

It will be appreciated that the shape of inner wall 7 of cavity 6 need not be frustoconical. It need not even consist of a surface or revolution. It would be sufficient to provide a sloping wall region which monotonically approaches the axis of the threaded opening 5 adjacent the slot to provide a cam surface for the head of the headed member to slide relatively to the body member. The adoption of a frustoconical surface makes fabrication easier. We have found that the cone half-angle should preferably be 30.degree. for best results. As will be seen from a comparison between FIGS. 3 and 4, we have also tested different configurations for the head of the headed member. That which we currently prefer is that illustrated in FIG. 3.

In order to close the through bore 3 against the possible ingress of foreign matter and to produce a pleasing appearance, a metal cover plate such as 21 may be threaded into opening 9 of body member 1. A similar cover plate may be integrally formed with threaded member 20 to close the other end of the through bore.

In assembling KD or systems furniture, particular attention has to be given to the structural parts (i.e. the parts which bear the weight of the furniture itself and of anything which may be placed upon it in use). For this reason, we prefer to connect together the load bearing uprights or sides of the KD furniture or units of the system and the load bearing horizontal members such as shelves or top panels in the manner described hereinabove. It may well not be necessary for the backs of the units or of KD furniture which will not be load bearing to be interconnected in the same way. As shown in FIG. 4, a back panel 22 may be connected to panel 4 by means of an intermediate L-shaped bracket 23 which has a stud 24 extending outwardly thereof. The stud 24 may be received in a centre aperture in threaded member 20. The other end of bracket 23 is connected to panel 22 by means of an elongate threaded member 25 provided with a substantial head 26 of appearance similar to cover plate 21, the shank of threaded member 25 being received through an aperture 27 of bracket 23, extending through a bore 28 in the panel 22 and being received at its end in a socket 29 of a further member 30 the external appearance of which may again be similar to cover plate 21.

In an alternative arrangement, location pin 31 of FIG. 5 may be employed. Location pin 31 is of configuration similar to the left-hand end of headed member 10 as depicted in FIG. 3 having a threaded end portion 32 generally similar to threaded portion 11 and a shank portion 33 of external diameter the same as shank 14 of headed member 10. Thus, the threaded end 32 of location pin 31 can be received in the bores 16 or 17 of a connecting rod 15 and the shank portion 33 of pin 31 is sized to allow a panel similar to panel 4 to be loosely coupled thereto by simply sliding shank portion 33 into a passage 19.