Abstract:
A novel fixing element (5) is proposed which extends over the entire housing base (2) of the switching device (1) and, with the housing base (2), forms a locking mechanism. Provided in the housing base (2) is a rectangular recess (3) which is substantially wider than the width of the profiled rail (4) and forms a nose (24) which grips round the profiled rail (4). The locking mechanism is formed by one end of the fixing element (5), and the other end has a second nose (23) which grips round the profiled rail (4). The fixing element (5) can subsequently be attached to the riveted or screwed-together switching device (1).

Description:
This is a continuation-in-part of copending applications Ser No. 07/350,523 filed on Mar.  17, 1989 and International Application PCT/CH/88/00120 filed on Jul. 7, 1988 and which designated the U.S. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Technical Field 
     The invention relates to an electrical switching device for fixing to a profiled rail. 
     2. Background Art 
     EP-A-0,184,143, for example, discloses such an electrical switching device. The switching device described there has a transverse-channel-like recess which is widened over the mounting rail area up to a housing margin. Two opposite noses surround the leg ends of the mounting rail, one nose being integrally formed on a slide. Pressure directed inwards is exerted on the slide by means of a torsion spring or an omega spring. This pressure is lifted when the switching device is pushed back. The switching device can be pushed back until the bus-bar no longer covers the outer contour of the contact parts. 
     However, the above slide requires an additional locking facility so that the switching device is not tilted when the contact screws are tightened. At the same time, the locking facility is intended to prevent the switching device from being released from the mounting rail by unintentional manipulation (striking, shaking or the like). This locking facility consists of a rocker or is integrally formed in one piece on the slide in the form of saw teeth, corresponding saw teeth being provided on the base surface of the switching device. A disadvantage in this arrangement is that the locking facility is on the same side as the terminal connections for the bus-bar. The locking facility is therefore concealed by the mounting rail. Consequently it is very awkward to unlock the locking facility of a switching device snapped onto the mounting rail. Furthermore, the slide has a claw which overlaps the legs of a mounting rail having a hat-like profile. The switching device can only be fixed to rails having a hat-like profile according to DIN EN 50022, since the claw does not permit the switching device to be snapped onto other mounting rails. 
     SUMMARY OF THE INVENTION 
     The object of the invention is then to achieve, in the electrical switching device of the above-mentioned type, improved fixing to a standardized and/or commercially available profiled rail. At the same time, a readily accessible locking mechanism of the fixing element is to be achieved. 
     For an electrical switching device of the above-mentioned type, this object is achieved by the features of Claim 1. 
     The invention has the great advantage that the fixing of lined-up switching devices to all conventional profiled rails is ensured. At the same time, every individual switching device can be pushed away particularly easily from the bus-bar and from the profiled rail. On account of the simple construction with a U-shaped spring clip or a detent-like leaf spring, the fixing element can be subsequently attached to the screwed or riveted switching device. The switching device is fixed very rigidly to the profiled rail in the longitudinal and transverse direction. This is especially important when aligning switching devices on the profiled rail. Another important advantage is that the locking mechanism is located on the side of the switching device which is opposite the bus-bar. This ensures that the locking mechanism is readily accessible and cannot be unlocked unintentionally when mounting on the bus-bar. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Further advantages of the invention follow from the description below. In the description, the invention is explained in greater detail with reference to exemplary embodiments shown in the drawings in which: 
     FIG. 1a shows a section along line 1a--1a in FIG. 1b and shows the lateral contour of a switching device having a locked fixing element, 
     FIG. 1b shows a section along line 1b--1b in FIG. 1a, 
     FIG. 2a shows a section along line 2a--2a in FIG. 2b and shows the same switching device as in FIG. 1a in the unlocked condition. 
     FIG. 2b shows a section along line 2b--2b in FIG. 2a, 
     FIG. 3a shows a contour of a switching device having a second, locked fastening element, 
     FIG. 3b shows a section along line 3b--3b in FIG. 3a, 
     FIG. 3c shows a section along line 3c--3c in FIG. 3a, 
     FIG. 3d shows a section along line 3d--3d in FIG. 3b, 
     FIG. 4a shows the same switching device as in FIG. 3a-3d, in unlocked, but still undisplaced condition, 
     FIG. 4b shows a section along line 4b--4b in FIG. 4a, 
     FIG. 4c shows a section along line 4c--4c in FIG. 4a, 
     FIG. 5a shows the same switching device as in FIG. 3a-3d and FIG. 4a-4c, but in displaced condition, and 
     FIG. 5b shows a section along line 5b--5b in FIG. 5a. 
     In the figures, the same reference numerals are always used for the same elements. 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     The contour of a switching device 1 is indicated in FIG. 1a. Provided in the housing base 2 is a wide recess 3 which is substantially wider than the width of the profiled rail 4 onto which the switching device, with a fixing or fastening element 5 displaceable in the housing base, is snapped. The profiled rail 4 has a hat-like profile and is commercially obtainable. The profiled rail 4 shown here has a combination of a hat profile and a C- profile and is made of aluminum. A bus-bar 6 is screwed to a terminal connection 7 which consists of a screw 8 and a connection piece 9. At its left hand end, the fixing element 5 has a locking mechanism which is formed from the end, designed as a wide extension 12, of the fixing element 5. The wide extension 12 is connected to a stepped part 13, narrowed towards the left, of the fixing element 5, as can clearly be seen from FIG. 1b. In this area, the housing base 2 is correspondingly narrowed with base lugs 10, so that the wide extension 12 prevents unintentional displacement of the fixing element 5. A small tongue 14 is located in the fixing element 5 approximately above the left hand leg of the profiled rail 4. The tongue 14 points slightly upwards and, on account of a stop 15 in the housing base 2, prevents the fixing element 5 from being displaceable too far to the right. To the left of the profiled rail 4, a projection 16 is provided at the bottom on the fixing element 5, which projection 16, when the switching device 1 is locked, strikes against the profiled rail 4. A U-shaped spring clip 17 is attached to the right hand part of the fixing element 5. Arranged above the right hand leg of the profiled rail 4 on the fixing element 5 is a claw 18 which engages round the center part of the spring clip 17. Located at the right hand end of the fixing element 5 in the marginal area are two small openings 19 into which the ends 20, bent downwards, of the spring clip 17 are hooked. The two legs of the spring clip 17 are formed with detents 21 protruding outwards, as is apparent from FIG. 1b. Opposed detents 22 protruding inwards are provided in the housing base 2, against which detents 22 the detents 21 of the spring clip 17 press (FIG. 1b). To the right of the profiled rail 4, a nose 23 is attached to the fixing element 5, which nose 23 engages round the right hand leg of the profiled rail 4. A nose 24 is likewise provided on the left hand side of the recess 3 in the housing base 2, which nose 24 engages round the left hand leg of the profiled rail 4. The right hand end of the fixing element 5 is provided with an enclosed slot 25 (FIG. 1b) into which a screwdriver can be inserted for displacing the fixing element 5. 
     In FIGS. 2a and 2b the fixing element 5 has been unlocked. For this purpose, the wide extension 12 is pressed down and the switching device 1 displaced to the left. The bus-bar 6 has thus been released (shown by broken lines) in FIG. 2b, and the switching device 1 can be turned away around the right hand leg of the profiled rail 4 and/or removed upwards from the bus-bar 6. Instead of a connection to a bus-bar, the switching device 1 can also be wired in a conventional manner. In this case, the fixing element 5 is advantageously displaced with a screwdriver in the slot 25 until the wide extension 12 makes contact. This slight displacement is then sufficient to remove the switching device 1 from the profiled rail 4. 
     In the FIGS. 3a, 3b, 3c and 3d is represented, by way of indication, a switching device 1 having a second variant of the fastening element 5 in the locked condition. Here, unlike the previously described embodiment, no spring is any longer provided as a separate element. For this, two springy tongues 51 are formed directly on the fastening element 5 itself. The free ends 52 of the springy tongues 51, arranged substantially parallel with each other, are bent outward and lie on slides 53 which are formed in the bottom of the housing base 2 of the switching device 1. The fastening element 5 is locked in the bottom of the housing base 2 by means of a blocking catch 54 formed between the two springy tongues, also on the fastening element 5. At its free end 55, the blocking catch 54 is designed hook-shaped and engages upward by this hook-shaped end with some play (in the lengthwise direction of the fastening element 5) in a corresponding opening 56 in the bottom of the housing base 2. The free end 55 of the blocking catch 54 is also flanged at the side by two ridges 58 springing forwardly inwardly in the bottom of the housing base 2. The above-mentioned play is measured so that the fastening element 5 can be pushed along in relation to the housing base 2 (or this latter in relation to the fastening element 5) precisely by the width of the nose 23 also formed on it. In this small zone of movement, the also formed on it. In this small zone of movement, the above-mentioned slides 53 in the housing base 2 are also provided with steep flanks 57 so that a relatively strong return force is provided through which the fastening element (in FIGS. 3a and 3b) is pressed to the right in the housing base 2. The nose 23 formed on the fastening element 5 is thereby pre-stressed elastically against the nose 24 formed on the housing base 2 by which the switching device 1 is allowed to snap onto the profiled rail 4. However, this is only possible when no bus-bar 6 is mounted. How the switching device 1 is set on the profiled rail 4 and can be connected to the bus-bar 6, even with the bus-bar 6 mounted, will be described further below. However, the reverse process should be explained first. 
     In order to be able to remove the switching device 1 which is snapped onto the profiled rail 4 with the bus-bar 6 mounted from the zone covered by the bus-bar 6, the tie screw 8 of the clamp connection 7 must first be loosened. Then the locking, described before, must be loosened. The limited possibility of movement of the fastening element 5 in the housing base 2, so long as the locking is still not loosened, does not suffice to be able to push the switching device 1 far enough away from the bus-bar 6. The loosening of tie locking takes place by pressing down the blocking catch 54 (for example, by means of a screwdriver) from the position shown in FIG. 3c and 3d into the position shown in FIGS. 4a and 4c. In the last-named position, the hook-shaped free end 55 of the blocking catch 54 is out of engagement with the opening 56 in the housing base 2. Because of the small catch and guide cams, the blocking catch 54 is caught in the unlocking position shown in FIG. 4c. The catch and guide cams formed on the ridges 58 or the free end 55 of the blocking catch 54 extending in between them may be seen well in FIGS. 3d and 4c. Unlocked in this way, the switching device 1 on the profiled rail 4 can be pushed from its position shown in FIGS. 3 and 4 into the position shown in FIG. 5a. In this position, covering no longer exists between the switching device 1 and the bus-bar 6. Therefore, the switching device 1 can be removed from the profiled rail unhindered by the bus-bar 6. 
     In pushing the switching device 1 onto the profiled rail 4, the return force must first be overcome, which is caused by the springy tongue 51 lying elastically against the steep flanks 57 of the slides 53. Beyond the steep flanks 57, the slides 53 widen somewhat outward again by which the direction of the setting force is reversed. This supports and facilitates the pushing process considerably. As can be seen from FIG. 5a, the fastening element 5 remains stationary with pushing of the switching device 1 out of the zone of overlapping with the bus-bar 6, since it engages by its nose 23 around the profiled rail 4 from the left. The zone of displacement is limited by a tongue 59 on the fastening element 5, which engages in a corresponding opening 60 in the housing base 2. In the position of maximum displacement of the switching device 1, shown in FIG. 5a in relation to the profiled rail 4, the tongue 59 is stopped at the left edge of the opening 60. 
     In order to set the switching device 1 or a correspondingly designed exchange device on the profiled rail 4 with the bus-bar 6 mounted and to be able to connect to the bus-bar 6, the procedure must be exactly opposite that described above. First of all, therefore, the fastening element 5 in the housing base 2 of the switching device 1 must be brought into the position shown in FIG. 5a. Through the slides 53 widening again beyond the steep flanks 57 (to the left), the fastening element 5 in the housing base 2 is held elastically into this position. The switching device 1 can now be set unhindered by the bus-bar 6 onto the profiled rail 4 and joined on these pushed to the left into overlap with the bus-bar 6. The function of the nose 23 in the removal of the switching device from the profiled rail 4, is namely to hold stationary the fastening element 5 with pushing along of the switching device 1, comes now to the projection on the fastening element 5. This latter, in pushing the switching device 1 to the left, strikes against the right leg of the profiled rail 4. As soon as the switching device 1 is pushed so far that the springy tongues 51 formed on the fastening element 5 come again into the zone of the steep flanks 57 of the slides 53, the return force again comes into action and drives the switching device 1 fully into its position shown in FIG. 3a. With this, the hook-shaped end 55 of the blocking catch 54 again comes into engagement with the opening 56, so that the prescribed locking of the fastening element 5 in the housing base 2 is provided again automatically. 
     It will be understood that the fixing elements revealed above can also include other variants.