Title of Invention	ELECTRICAL DEVICE COMPRISING A FRONT COVER
Abstract	This invention relates to an electric appliance having a cssing (2) composed of two identically built casing shells (1) mounted in mirror inversion to one another. The casing (2) is provided with a snap-on mount for snap attachment to a mounting rail, and that the snap-on mount is implemented by two spring locking hooks (6), one of which is integrated into each of the casing shells (1).

Full Text

The invention relates to ,an electrical device comprising a front coverand a housing which is provided with a snap fastening for snapping onto a mounting rail. A device of the generic type is known from DE 296 06 759 U1. This discloses a multi-part housing of modular design for receiving a printed circuit board. What they have in mind here is a multi-part housing for low-voltage switchgear, such as for example time-lag relays or thermistor protection devices, for receiving a printed circuit board. Here, the housing is divided parallel to the mounting plane into a lower and upper housing part. The printed circuit board is designed such that it is graduated in a step-shaped manner along two mutually opposite edges and is equipped with connection plugs for the fitting on of screw terminals designed in block form in the region of the step-shaped graduations. The connection plugs have not only contact pins but also fastening pins, which may be made in the form of hook-shaped lockable fastening pins. DE 30 26 247 C2 discloses a housing which can be arranged in series and is intended for mounting on a supporting rail. A circuit board, on the edges of which electrical connection elements are arranged, can be inserted into the housing. The connection elements protrude partially out of the openings in the housing. Here, the housing is divided perpendicularly with respect to the mounting direction, in the longitudinal direction of the housing. The invention is based on the object of providing an electrical device of the type mentioned above for creating a housing of a simple, low-cost construction which is easy to assemble and comprises few parts. The object is achieved by the housing being composed of two housing shells of identical construction which are assembled mirror-invertedly with respect to each other. A particularly advantageous development of the invention is for the two housing shells to be connected to each other by formed-on catch elements. A particularly simple configuration minimizing the number of details is achieved if the snap fastening is realized by two resilient catch hooks, of which in each case one is integrated respectively in one housing shell. The configuration with two housing shells of identical construction which can be assembled mirror- invertedly with respect to each other can be achieved if the two housing shells in the assembled state form a separating gap which leads through the axes of symmetry of two mutually opposite side walls and outside the resilient catch hooks. A particularly advantageous configuration of the connection terminals, in particular their connection, is obtained if there is mounted in the space inside the housing a printed circuit board with at least two terminal insulators, which are snap-fitted into the printed circuit board and the connection lugs of which, belonging to connection terminals, are in electrical connection with the printed circuit board by means of soldering. Furthermore, it is advantageous if connection terminals are integrated in the electrical device and, for adding further connection terminals, on one side wall of the two housing shells there can respectively be clipped on a terminal block with connection terminals, into which connection lugs protruding out of the housing from terminal insulators slide during clipping on. A further advantageous design of the invention is for the switchgear to have on the front side at least one knob, as a setting element, with an adjusting securement inasmuch as a mechanically coded plate can be clipped onto the knob, the mechanical coding of the plate corresponding to a specific setting of the knob. An exemplary embodiment of the invention is explained in more detail below with reference to a drawing, in which: FIGURE 1 shows a perspective view of a housing which can be fitted together from two housing shells of identical construction, FIGURE 2 shows a perspective view of an inventive electrical device in a partially open state, FIGURE 3 shows a perspective view of a terminal insulator, FIGURE 4 shows a Sside view of the terminal insulator according to FIGURE 3, FIGURE 5 shows a perspective view of a plate serving as an adjusting securement and FIGURE 6 shows a perspective view of an electrical device with a front cover which can be lead- sealed. Represented in FIGURE 1 are two housing shells 1 of identical construction and lying mirror-invertedly with respect to each other, which can be fitted together by means of catch elements 3, 4 at their edges to form a housing 2 of an electrical device according to the invention. As usual, the catch elements 3, 4 comprise formed-on catch hooks 3 and adapted clearances 4. For stabilizing the fitted-together housing 2 and for easier assembly, the housing shells 1 have at their edges tabs 5, which on the one hand make assembly easier on account of their guiding function and on the other hand have a stabilizing effect on account of the overlap with side walls of the respectively other housing shell 1. On the side walls of the housing shells 1 forming the rear wall of the housing 2 there is respectively formed a resilient catch hook 6. They serve for the snap fastening of the housing 2 on a mounting rail and make demounting possible without a tool being required. The resilient catch hook 6 integrated in the housing shell 1 is dimensioned with respect to its force-deformation characteristic such that, given a defined maximum device weight and defined maximum accelerations, the prestress in the clipped-on state is sufficient for securely fixing the device. The separating gap between the two housing shells 1 in the assembled state leads through the axes of symmetry of two opposite side walls 7 and 8 and outside the resilient catch hooks 6. FIGURE 2 shows a perspective view of the electrical device according to the invention, one housing shell 1 and a front cover 9, which reaches over both housing shells 1 in the assembled state, having been removed. In the housing shell 1 represented there has been fitted a printed circuit board 10 belonging to the electrical device, on the edges of which board a plurality of terminal insulators 11 are mounted. The terminal insulators 11 are respectively of a 3-pole form, i.e. they have 3 encapsulated terminal lugs 12. For assembly, the terminal insulators 11 (see also FIGURES 3 and 4) are initially clipped into the printed-circuit board 10 and then soldered. During the mounting of the printed circuit board 10 in the housing shells 1, the terminal lugs 12 of the terminal insulators 11 brought into electrical contact with the printed circuit board 10 in this way slide in clamping cages 13, which are only indicated here and have been inserted into pockets of the housing shells 1 formed in a corresponding way. The connection lugs 13 of the terminal insulators 11 neighbouring the resilient catch hooks 6 protrude laterally out of the housing 2 and can be used for adding further connection terminals, for which purpose terminal blocks 15 are clipped on in this region of the housing 2. In this way, the usually 6-pole devices can be increased to 12 poles. The housing 2 can be covered on the front side by a cover 16. Once the cover 16 has been fitted on, the clamping screws (not shown) belonging to the connection terminals on the housing side are mounted from outside via screw openings 17 and are secured against being lost by means of integrated catches 18 (not visible here) in the region of the screw openings 17. According to FIGURES 3 and 4, the terminal insulators 11 are symmetrically shaped, which makes it possible for them to be installed offset by 180° at the various installation positions on the printed circuit board 10. Consequently, just one configuration of a terminal insulator 11 is sufficient to cover all applications. On the front side of the electrical device according to FIGURE 2 there are setting elements, which can be actuated by means of knobs 19. The knobs 19 have mechanical codings 20, the position of which changes correspondingly with the angle of rotation of the respective knob 19. By means of correspondingly mechanically coded plates 21 which can be clipped onto the mechanical codings of the knobs 19, according to FIGURE 5, the knobs 19 can be protected against unintentional adjustment. On each plate 21 there has been applied the setting value matching the rotary position or the matching setting function, in plain text or in graphic representation. On account of the mechanical coding between the knob 19 and the plate 21, a particular plate 21 can be clipped on only if the knob 19 is in the appropriate position. It is thus possible by varying the position of the catches 22 to achieve a coding between a number of variants of the device. Consequently, the purely functional setting is realized in a simple and low-cost way by means of knobs 19, with the additional function of an adjusting securement and visible assignment of a setting value or function in plain text and graphic representation. Once the knobs 19 have been set, they may also be covered, for example by. a transparent injection moulding 23 according to FIGURE 6. The cover 23 can be lead-sealed by means of a locking part 24, which is hooked in the housing. Although the present invention is explained with reference to the embodiment represented in the accompanying drawing, it should be taken into consideration that this is not intended to restrict the invention only to the embodiment represented but rather to include all possible changes, modifications and equivalent arrangements, to the extent that they are covered by the content of the patent claims. WE CLAIM: 1. Electric appliance having a casing (2) composed of two identically built casing shells (1) mounted in mirrow inversion to one another, characterized in that the casing (2) is provided with a snap-on mount for snap attachment to a mounting rail, and that the snap-on mount is implemented by two spring locking hooks (6), one of which is integrated into each of the casing shells (1). 2. Electric appliance as claimed in claim 1, wherein the two casing shells (1) are joined together by integrally moulded catch elements (3,4). 3. Electric appliance as claimed in one of the preceding claims, wherein a circuit board (10) having at least two terminal insulators (11) is mounted in the interior of the casing (2), the terminal insulators being snapped into the circuit board (10) and their terminal lugs (12) belonging to the terminals being electrically connected to the circuit board (10) by soldering. 4. Electric applicance as claimed in one of the preceding claims, wherein terminals are integrated into the electric appliance, for adding additional terminals for expansion, a terminal block (15) can be locked onto in each case one side wall of the two casing shells (1), the terminal block having terminals-into which side the terminal lugs (12) of terminal insulators (11) projecting out of the casing (2) when locked together. 9. Electric appliance as claimed in one of the preceding claims, wherein the appliance has on the front side at least one turning knob (19) as an adjusting element having an adjustment securing device, where a mechanically coded plate (21) can be locked onto the turning knob (19), with the mechanical coding of the plate corresponding to a certain position of the turning knob (19). ABSTRACT ELECTRIC APPLICANCE HAVING A CASING (2) COMPOSED OF TWO IDENTICALLY BUILT CASING SHELLS (1) This invention relates to an electric appliance having a cssing (2) composed of two identically built casing shells (1) mounted in mirror inversion to one another. The casing (2) is provided with a snap-on mount for snap attachment to a mounting rail, and that the snap-on mount is implemented by two spring locking hooks (6), one of which is integrated into each of the casing shells (1).

Documents:

580-CAL-1998-ABSTRACT.pdf

580-CAL-1998-CLAIMS.pdf

580-CAL-1998-CORRESPONDENCE.pdf

580-CAL-1998-DESCRIPTION (COMPLETE).pdf

580-CAL-1998-DRAWINGS.pdf

580-CAL-1998-EXAMINATION REPORT.pdf

580-CAL-1998-FORM 1.pdf

580-CAL-1998-FORM 2.pdf

580-CAL-1998-FORM 3.pdf

580-CAL-1998-FORM 4.pdf

580-CAL-1998-FORM 6.pdf

580-CAL-1998-GPA.pdf

580-CAL-1998-OTHERS.pdf

580-CAL-1998-REPLY TO EXAMINATION REPORT.pdf

580-CAL-1998-SPECIFICATION.pdf