Abstract:
Coupling sleeve for the interconnection of hollow prismatic objects from sheet material, such as channel segments of an air heating device, said sleeve having a U- or W-shaped cross section, the limbs of this cross section having different length for facilitating the insertion of the edge of said prismatic objects into said coupling sleeve.

Description:
BACKGROUND OF THE INVENTION 
     My invention relates to a coupling member for coupling to each other two channel elements made of sheet material. These channel elements may e.g. consist of sections of an air channel of an air heating device to be used in an air circulation or conditioning system. Such channel elements are usually interconnected by means of screw bolts, rivets, welded joints etc. 
     My invention aims to provide a coupling member by means of which various channel elements can be interconnected in a manner which is less time consuming and less complicated in comparison with the known connection methods. 
     SUMMARY OF THE INVENTION 
     According to my invention the coupling member consists of a coupling strip or sleeve with sectional form such that it can receive the ends of the channel elements. The only requirement for interconnecting two channel elements is therefore to slide them into the recesses of the respective sleeve. Apart from the fact that this assembly is detachable, and can be easily mounted, while its construction is simple, it also meets sufficiently the requirements imposed from the aesthetic view point. Furthermore the edges of the channel elements need no special pre-treatment nor need they meet strict requirements imposed for tolerance. It is not necessary for instance that the edges of a channel element lie exactly in a particular transverse plane since the sleeve can easily correct small variations in size. 
    
    
     SURVEY OF THE DRAWINGS 
     FIG. 1 shows a longitudinal section through an assembly of two partially shown channel elements, which are interconnected by a coupling sleeve according to a first embodiment of my invention; 
     FIG. 2 shows a longitudinal section through an assembly of two partially represented channel elements which are provided with a layer of insulating material and which are interconnected by a sleeve according to a second embodiment of my invention; 
     FIG. 3 shows on a larger scale a detail of a section through a coupling sleeve, a fixing member being applied. 
     FIG. 4 is an isometric view of FIG. 3. 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     In FIG. 1 two channel elements 1,1&#39; are connected by a coupling sleeve 2 according to my invention. The cross section of the channel elements 1,1&#39; may have any arbitrary shape. The outline of the coupling sleeve 2 corresponds to the shape of the cross section of the channel elements 1,1&#39;. 
     Coupling sleeve 2 shows in sectional form two parallel flanges or limbs 4,5 interconnected by a web portion 3. The two flanges 4,5 enclose the edges of channel elements 1,1&#39; since the length of web portion 3 corresponds to the thickness of the sheet material from which the channel elements 1,1&#39; are manufactured. 
     Flange 5 which is on the inside of the channel elements 1,1&#39; is wider than flange 4 situated on the outside. When mounting the connection it becomes possible to apply at first the coupling sleeve by the wider flange 5 against the innerwall of the channel elements 1,1&#39;. Subsequently the channel elements 1,1&#39; can be slid towards each other, while one need only see to it that the narrow flange 4 falls over the outer wall of the channel elements 1,1&#39;. 
     The coupling sleeve 2&#39; shown in FIG. 2 has three parallel limbs or flanges 4, 5, 6 and is destined for interconnection of the channel elements 1,1&#39;, which are each provided with a layer 7,7&#39; of e.g. insulating material like glass wool. The flanges 4, 5, 6 differ mutually as to width. The widest flange 6 is on the inside of the channel elements 1,1&#39; and the narrowest is on the outside. Since the flanges differ in width, the whole can be stepwise assembled and the various layers need not simultaneously fall into the openings meant therefor. 
     FIG. 3 shows an embodiment in which a fixing element is disposed between flanges 4,5 of the coupling sleeve 2. This fixing element consists of a loose resilient strip 8 provided with obliquely protruding teeth 9. When the channel element 1&#39; moves in the direction indicated by the arrow P the fixing element becomes wedged between the flange and the channel element 1&#39;, whereby this shift is counteracted. A shift in the opposite direction can, however, be performed without any difficulty. Strip 8 ensures therefore a firm connection between coupling sleeve 2 and channel element 1&#39;, while the whole structure can be assembled easily. 
     It is evident that the front ends of the channel elements 1,1&#39; of the layers 7,7&#39; need not necessarily lie against the web portion 3. Therefore the shape exactness of the ends of the channel elements 1,1&#39; need not meet strict requirements. For a proper functioning of the coupling sleeve it suffices that the inner- and outer walls of the channel elements 1,1&#39; and the layers 7,7&#39; contact the concerning flange 4 and 5 or 5 and 6 respectively. 
     Besides for coupling the channel elements 1,1&#39; to each other, the coupling sleeve 2,2&#39; can also be used for disposing end covers on the channel elements 1,1&#39;. 
     The channel elements 1,1&#39; which consist of short units can be assembled by means of connecting sleeves 2,2&#39;, so as to form air channels of any desired length.