Abstract:
The invention relates to a device for fixing switchgears ( 2,4 ) on mounting rails, especially top hat rail adapters, comprising lower fixing means ( 8 ) which are used to secure the device on the mounting rail and upper fixing means ( 10   a   , 10   b ) which are used to secure at least one switchgear ( 2,4 ) on the device. According to the invention, at least one of the active elements ( 8   b   ; 10   b ) is mounted in such a way that it can move in a linear manner on the fixing axis (X).

Description:
BACKGROUND 
     The present invention relates to a device for fixing switching devices to mounting rails. 
     A mounting plate for attachment of a switching device combination including a contactor and a circuit-breaker is already known from German Publication DE 296 17 112 U1. This mounting plate features, on its back side, a top-hat rail fixing device for fixing the mounting plate to the top-hat rail and, on its front side, a top-hat rail for fixing a switching device to the mounting plate. The mounting further has two rows of holes which run parallel and are used for optional attachment of a further top-hat rail to the mounting plate. 
     SUMMARY OF THE INVENTION 
     The object of the present invention is to provide a device of this type, which makes easier to fix a device combination to a mounting rail, while providing high fastening security of the device combination on the mounting rail. 
     The present invention provides a fixing apparatus for fixing a switching apparatus to a mounting rail. The fixing apparatus includes a lower-side fixing device configured to fix the fixing apparatus to the mounting rail and including a first and a second active element which oppose each other; and an upper-side fixing device configured to fix the switching apparatus to the fixing apparatus and including a third and a fourth active element which oppose each other. At least one of the first, second, third, and fourth active elements is supported in a linearly movable manner such that the distance to the opposite active element is variable so as to provide a plurality of fixing positions. 
     The device according to the present invention is preferably designed as an adapter for top-hat rail profiles and provided, on its back side, with first means for attachment to a mounting rail and, on its front side, with second means for attachment or of a switching device or a switching device combination. The means for fixing a switching device or a switching device combination are preferably designed as L-shaped profile appendages, as they are known as the unilateral undergrip portion of a top-hat rail profile. The adapter is essentially constituted by an elongated, cuboidal base plate which, on its front side, is provided at one end with a fixedly arranged first active element for engagement with a mounting recess of a first switching device of the switching device combination and which, at a distance from this first active element, preferably at its other end, features a second active element, which is supported on the base plate in such a manner that it is linearly movable in its mounting axis X. In this context, the first active element is preferably formed in one piece with the base plate, which is composed of insulating material, while the second active element is preferably formed in one piece with a holding element, which is composed of insulating material and is arranged on the base plate in such a manner that it is linearly movable. In a preferred embodiment, the linearly movable active element is formed as a block-like or as a cap-like part of the base plate which is movable on the base plate and embraces the base plate in regions thereof, the block-like or cap-like part being biased outwardly by spring means in a direction away from the fixed active element. 
     In this context, the holding element is provided, on its upper side, with an L-shaped fixing profile for engagement with the opening of a mounting recess of a switching device. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Further details and advantages of the present invention will be explained below based on exemplary embodiments with reference to the drawings. 
     FIG. 1 shows a switching device combination (for example, a motor starter combination); 
     FIG. 2 depicts a possible embodiment of the device according to the present invention for fixing a switching device combination; and 
     FIG. 3 shows a further possible embodiment of the device according to the present invention for fixing a switching device combination. 
    
    
     DETAILED DESCRIPTION 
     According to FIG. 1, a possible switching device combination to be secured to a mounting rail having a top-hat rail profile or the like is composed of a contactor  2  and a motor protection switch  4 . In the embodiment shown, the two separate devices are interconnected and wired up by a preferably rigid connecting piece  6  (wiring adapter). Once the switching device combination is mounted to the fixing device, the connection area of the two switching devices is protected in a stabilizing manner by the upper side of the fixing device. In this manner, connecting piece  6  is freed from mechanical stress. 
     FIGS. 2 and 3 each show a possible embodiment of the device according to the present invention. This device is preferably designed as a top-hat rail adapter and provided, on its side facing the mounting rail (lower side), with first fixing means  8  for fixing the device to a mounting rail. On its side facing away from the mounting rail (upper side), the device features second fixing means  10  for attachment of a switching device, in particular, of a switching device combination  2 ,  4 ,  6  according to FIG.  1 . Each of fixing means  8 ;  10  includes active elements  8   a ,  8   b ;  10   a ,  10   b  which oppose each other in pairs. 
     According to the present invention, at least one of active elements  8   b ;  10   b  is supported in such a manner that it is linearly movable along mounting axis X. In this context, the respective active element  8   b ;  10   b  is designed and supported on base plate  14  of the device in such a manner that it can be transported from a first fixing position I to a second fixing position II which is axially spaced from first fixing position I. It is preferred for active element  8   b ;  10   b  to extend over the whole width b of base plate  14 , as shown in FIGS. 2 and 3. 
     This method of mounting upper-side active elements  10   a ,  10   b  is preferably accomplished in that movable active element  10   b  is biased outwardly by a spring means  12  along its axis of motion away from the center point of the device. This, first of all, makes it easier to mount switching device combinations according to FIG.  1  and it is only through this that the mounting of preassembled switching device combinations becomes possible. Secondly, dimensional tolerances of the fixing means of the fixing device and dimensional tolerances of the switching devices are compensated for. A further advantage is achieved if movable active element  10   b  is arranged so close to the end of base plate  14  of the device that it projects over base plate  14  of the device in the direction of mounting axis X so that, when the device combination is installed, the fixing device is always only as long as is actually required (the adapter is pushed together). This saves valuable space in the mounting space (for example, a switchgear cabinet). Because of the achieved compensation of tolerances, moreover, the noise which is produced by the mounted switching device combination due to the switching operations is reduced in that a lateral displacement of the combination on the top-hat rail or on the fixing device is minimized through the spring-loaded fixing means. The fixation of switching devices  2 ,  4  is advantageously further assisted by the device having spring means  15  on the upper side which exert a spring force against at least one of the switching devices when the switching device combination is in the installed position. A spring means  15  of that kind can be designed, for example, in the form of a flexible leg which is injected on base plate  14  and presses against one or each of switching devices  2 ,  4  from below. In another embodiment, an elastic spring element can be designed in the form of a spiral spring or of an elastic foamed plastic part or the like. 
     The mounting of a preassembled device combination on the adapter according to the present invention is carried out as follows: 
     Starting from a fixing device according to the present invention which is mounted on horizontally running mounting rails, a switching device combination is to be mounted to the fixing device in that the device combination grips behind linearly movable active element  10   b  with the lower recess A of first switching device  2 , active element  10   b  is moved against spring force f 1 , and second switching device  4  is hung on stationary active element  10   a  with its upper recess B. 
     According to FIGS. 2 and 3, upper-side active elements  10   a ,  10   b  are preferably designed as L-shaped profile appendages, providing a similar shape to known unilateral undergrip portions of a top-hat rail profile. The fixing device includes an elongated, cuboidal base plate  14  which, on its front side, is provided at one end with at least one fixedly arranged first fixing appendage (active element  10   a ) for engagement with a mounting recess of a switching device and which, at a distance from this first appendage, preferably at its other end, features a second fixing appendage (active element  10   b ), which is supported on base plate  14  in such a manner that it is linearly movable along mounting axis X. In this context, first active element  10   a  is preferably formed in one piece with base plate  14 , which is composed of insulating material, while second active element  10   b  is preferably formed in one piece with a holding element  11 , which is arranged on base plate  14  in such a manner that it is linearly movable. To be able to mount different switching device combinations of markedly different size and consequently also of markedly different length, provision can be made for several active elements  10   a  in order to permit adjustment to greater distances of mounting recesses A, B of the switching devices of a combination. As an alternative to this, it is also possible to provide a single active element  10   a  which can be locked in different positions on base plate  14 , for example, by means of spaced apart latch positions. 
     In a preferred embodiment, linearly movable holding element  11  is formed as block-like or as a cap-like or part of base plate  14  which is movable on base plate  14  and embraces base plate  14  in regions thereof, the block-like or cap-like part being biased outwardly by spring means  12  in a direction away from fixed active element  10   a.    
     According to FIG. 2, holding element  11  is designed as a cap-like element. In this context, when viewed in cross-section, holding element  11 , has an essentially U-shaped design, featuring inwardly directed appendages  16  at its lateral leg parts embracing base plate  14 . These appendages  16  engage with corresponding guide grooves of base plate  14 . Spring element  12  is designed, for example, as a spiral spring and, in the exemplary embodiment shown, is located between base plate  14  and holding element  11  essentially axially. 
     In another embodiment of holding element  11  according to FIG. 3, the holding element is designed as a block-like element. In this context, holding element  11  can be connected to base plate  14 , for example, via screws  18  instead of being guided via guide grooves as in FIG.  2 . To this end, base plate  14  is provided with tapped holes  20  to accommodate screws  18 . The screws are guided in blind holes  22  of holding element  11  and biased outwardly by a spring force f 1  against base plate  14  via spring elements  12 . 
     The present invention is not limited to the specific embodiments described above but includes also all equally acting embodiments along the lines of the present invention. In a further refinement of the present invention, analogously to holding element  11 , which is supported in such a manner that is linearly movable and used for fixing a switching device combination  2 ,  4 ,  6  to the upper side of the device according to the present invention, at least one of lower-side active elements  8   a ,  8   b  is also designed to be linearly movable. To this end, active element  8   b  of the dovetailed recess (lower-side fixing means  8 ) is supported in such a manner that it is linearly movable along mounting axis X to accommodate a top-hat rail. In this context, active element  8   b  is also preferably connected to base plate  14  via two screws  28  and biased by spiral springs  32  located on screws  28  with a spring force f 2  which is directed into the interior of the mounting fixture. Moreover, all features shown in the drawing belong to the present invention as well. In particular, the geometry as shown. Moreover, provision can be made for fixation means which are used to fix linearly movable active elements ( 8   b ;  10   b ) in position. These fixation means can be designed, in particular, as a locking screw for fixing the corresponding movable means in an installed position relative to base plate  14 .