Abstract:
A device for fixing panels for constructing a piece of furniture, a bookcase, or a cupboard, comprises a first element which engages with a first panel, a second element which engages with a second panel designed to be assembled essentially perpendicular to the first panel, and a third element which engages with each the first and second elements, and a pulling device for acting on the third element so that when the two panels are assembled, the first and second elements are pulled toward each other. The third element is a high-tensile wire.

Description:
The present invention relates to a device for fixing panels together for constructing a piece of furniture, shelving, a cupboard or the like, according to the preamble of claim 1. 
     There are numerous fixing devices by means of which it is possible to connect two panels so as to construct, for example, shelving, namely: 
     by means of screws and screw nuts with a right-angle bracket; 
     by means of male and female elements mounted respectively on each of the two panels and designed so that when the latter are assembled they fit into one another; or 
     by means of a pin, one end of which engages with a cam mounted inside the other panel, so that, by rotating the cam, the two panels are pressed towards one another. 
     In principle, when two panels are connected, the edge of one comes to lie flat against a face of the other. 
     The aforementioned fixing systems are perhaps well adapted to solid panels, but they have drawbacks with hollow panels of the type formed, for example, by two plates, which are joined at their periphery by means of a frame; in fact, when such hollow panels are interconnected by means of fixing devices known until now, they are subject to bending, torsional, pressure and shearing stresses which deteriorate them by local or overall deformation. 
     The problem raised above is resolved thanks to the fixing device according to claim 1. 
     There is now described an embodiment for fixing two panels which are designed to form shelving and connected by means of two devices as specified by the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     FIG. 1 diagrammatically shows two hollow panels P, Q by dot-and-dash lines so as to make it easier to understand the drawing. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The two panels P, Q are rectangular so as to form shelving. A horizontal panel P has to be fixed to another vertical panel Q so that an edge of the horizontal panel comes into contact with one of the faces of the vertical panel Q and so that thus the two panels P, Q are perpendicular to one another after assembly. 
     Of course a horizontal panel P is simultaneously connected to two vertical panels Q opposite one another. However, in FIG. 1 the second panel Q has not been shown so that the drawing does not become unnecessarily complicated. 
     The horizontal panel P is fixed to the vertical panel by means of two attachment devices S1 and S2, with S2 being slightly different from S1. 
     Each fixing device S comprises a pin A, a wire D, a rod B, a disc C and a screw E. 
     At each of its four corners, the horizontal panel P is provided with a circular aperture R which passes through its entire thickness or at least opens on one face. Into each of the apertures R there is introduced, in free rotation, an axle in the form of a pin A, the ends of which are approximately on the same level as the two faces of the horizontal panel P, as shown in the part of the drawing shown by thick continuous lines. In fact, the pin A is engaged in free rotation inside an aperture R provided in each of the two plates which form the horizontal panel P. 
     In system S1, a first end of the wire D is fixed to the pin A so that when the latter is brought into rotation, the wire is wound around it. The rod B is provided with two longitudinal passages I and J. The disc C is pierced by two holes. From the pin A, the wire firstly passes by freely sliding through a first passage J of the rod B, then also freely through a first and then the second hole in disc C, and finally through the second passage I of the rod B, but without being able to slide, to which rod B the second end of the wire D is fixed. 
     Before the assembly of the two panels P, Q, the fixing device is assembled inside the horizontal panel P so that the part of the wire D provided with the disc C emerges from an aperture Y provided in the longitudinal edge of the horizontal panel P, with the edge coming into contact with the vertical panel Q. 
     The dimensions and shape of the disc C and of the aperture Y are chosen so that the disc C can not pass through the aperture Y, or can only do so with difficulty. 
     Exactly opposite the aperture Y, at the place where the horizontal panel P has to be fixed onto the vertical panel Q, the latter is provided with an aperture X through which the disc C can pass. 
     Similarly, the dimensions and the shape of the aperture X are chosen so that the rod B can pass through this aperture with slight play. 
     It is possible to see on the drawing that, when disc C of the system S1 is put inside the vertical panel Q, a rotation of the pin A produces a reduction in the free length of the wire D, which firstly causes the disc C to come to lie flat against the internal surface of a wall of the vertical panel Q, with said surface situated at the site of aperture X, and secondly the rod B to move towards and through apertures X and Y to come to abut disc C. 
     The pin A is provided with a through hole N pierced perpendicular to its axis. At the height of the through hole N the periphery of the pin A is also provided with a radial groove so as to reduce the section of the walls surrounding the through hole N. 
     In each of the two end sections of the pin is made a slot 0, 01 situated on the axis of the pin. Similarly scores F, F1 parallel to the axis of the pin A are made on the periphery of each end of the latter. 
     The end of wire D passes partly around pin A inside groove M so that, when the latter is brought into rotation, its weakened central part, around which the wire D is wound, becomes compressed by the tension of the wire D, whereas the two end sections, provided with slots 0, 01, become larger by moving in the direction of arrows G, so as to effect rotational self-locking by the friction of the pin A against the walls of aperture R. Moreover a screw E is provided, which engages with a thread situated in one of the end sections of the pin A and serves to lock definitively the pin A. Of course the screw, which may be self-tapping, increases the safety of the attachment. 
     The function of the rod B, which fits into panel Q through aperture X, lies in the absorption of the shearing stresses between the two panels P, Q as, if the wire D has a good tensile strength, its shearing strength is generally poor. The wire D used is of the high-tensile type, for example made of carbon fibre, Kevlar, etc. 
     Thus, except for steel screws E, all the other components of the fixing device may be made from aluminium, which can be easily and economically recycled. 
     Dismantling is as easy as assembly, since all that needs to be done is remove the screws E, turn the pin A in the opposite direction to arrow L and then remove disc C through aperture X. 
     In system S2, so as to simplify assembly even more, it is proposed that a single wire D be used for two fixing devices II and III situated in the same horizontal panel and respectively near two opposite edges. Except for the circuit of the wire D, all the components A, B, C, E of system S2 are identical to those already described for system S1. Similarly, the circuit of wire D for a first fixing device II of system S2 is similar to I of the system S1. The circuit of the wire D for device III is formed by an extension of the wire D from pin A of device II, with the wire D then passing along the side of pin A of device III, then in sequence through: 
     passage J of rod B (with a sliding motion), 
     the two holes in disc C, 
     hole I in rod B (without a sliding motion), 
     hole N in pin A, 
     before finally passing alongside pin A of the other device II and then without interruption rejoining rod B in the second passage I, with the wire as it were describing a closed circuit. 
     As can be seen on the drawings, in the case of system S2, it is possible, by rotating, for example, pin A of device II, to move its rod B and simultaneously that of device III. This also greatly facilitates the assembly or dismantling of the three panels, i.e. a horizontal panel P and two vertical panels Q. Moreover, by rotating pin A of device III wire D is tightened, which enables the two rods B of devices II and III to be simultaneously retracted after having released pin A of device II during the dismantling operation. 
     It should be noted that the tightening of wire D helps to improve the bending strength of horizontal panel P. 
     As an alternative, in system S1 it is also possible to extend wire D (shown by dot-and-dash lines) from the second passage I to pin A to which it will also be fixed, which will facilitate the dismantling of panel P, as a reverse rotation of the pin A, which has previously been released, will enable rod B to be retracted.