Title of Invention

A CASE FOR AN ELECTRICAL APPARATUS SUCH AS A CIRCUIT BREAKER

Abstract

A case for housing an electrical apparatus such as a circuit breaker comprising, at least in one of its ends a plurality of terminal compartments housing connection strips and means for fixing said strips to external conductors such as a bar, a cable etc., characterized in that said means comprises, for at least one of the previously mentioned compartments, at least a first opening provided in the case, at least a second opening provided in the connection strip and situated facing the first opening(s), and at least one screw passing through two orifices facing one another I provided respectively in the case and in the strip to perform fixing of a conductor onto the connection strip, said first opening being shaped in such a way as on the one hand to receive and guide in rotation at least one screw head of circular shape, and on the other hand to block in rotation with respect to the case at least one screw head of suitable non-circular shape.

Full Text

A CASE FOR AN ELECTRICAL APPARATUS SUCH AS A CIRCUIT BREAKER BACKGROUND OF THE INVENTION The present invention relates to a case designed for housing an electrical apparatus such as a circuit breaker and comprising, at at least one of its ends, terminal compartments in which there are respectively housed connection strips and means for fixing said strips to external conductors such as a bar, a cable etc. Different possibilities currently exist for power connection of a low voltage circuit breaker via the front of the apparatus. Connection to cables by means of terminals, connection to bars or connection of the "disconnectable" type to a fixed rigid conductor are in fact known. Generally, switching from one connection mode to the other requires the use of different parts. For example, for fixing a connection strip to a bar, the screws have to be immobilized in rotation. One of the solutions used consists in fitting the screws in metallic clips or small insulating plates fixed in removable manner to the connection strips. After the bars have been mounted on the screws, the latter are secured on the connection strips by nuts. On the other hand, for connection to power cables, immobilization of the screws in this way is not necessary. The latter are fitted across the strips via the rear of the apparatus and screwed directly into the terminals fitted for this purpose on the connection strips. According to these embodiments, the isolation distances are ensured either by a cover screwed under the apparatus (in the case of use of a clip) or by a suitable shape and dimensions of the previously mentioned plate, when the latter is used. SUMMARY OF THE INVENTION The present invention proposes a case for an electrical apparatus of simple design enabling different types of connection to be achieved using a minimum of parts. For this purpose, the object of the present invention is to achieve a case of the previously mentioned kind, characterized in that the means for fixing the strips to the conductors comprise, for at least one of the previously mentioned compartments, at least a first opening provided in the case, at least a second opening provided in the connection strip and situated facing the first opening(s), and at least one screw passing through two orifices facing one another provided respectively in the case and in the strip to perform fixing of a conductor onto the connection strip, said first opening being shaped in such a way as on the one hand to receive and guide in rotation at least one screw head of circular shape, and on the other hand to block in rotation with respect to the case at least one screw head of suitable non-circular shape. According to a particular feature of the invention, the screws with circular heads are designed for fixing terminals onto the connection strip. According to a particular feature of the invention, the previously mentioned screws with non-circular heads are designed for fixing bars onto the connection strips. According to another feature, the or each first opening is also designed to receive a fixed rigid conductor. According to another feature, the or each first opening forms at least one housing of appreciably hexagonal shape cooperating with at least one screw whose head is appreciably of the same shape. BRIEF DESCRIPTION OF THE DRAWINGS But other advantages and features of the invention will become more clearly apparent from the following detailed description which refers to the accompanying drawings given for example purposes only and in which : Figure 1 is a partial perspective view, illustrating the rear part of a low voltage circuit breaker housed in a case according to the invention and in which the "terminal" type connection mode is used, Figures 2 and 3 are partial longitudinal sectional views of the previous figure, respectively in the non-connected and connected position of the cable. Figure 4 is a sectional view similar to figures 2 and 3, illustrating the bar type connection mode, Figure 5 is a partial perspective view, illustrating the front part of the case of a circuit breaker, the disconnectable type connection mode being used. Figure 6 is a partial longitudinal sectional view of figure 5, and Figure 7 is a partial perspective view, illustrating the rear part of a low voltage circuit breaker housed in a case according to another embodiment of the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT In figure 1, a low voltage power circuit breaker D can be seen housed in a molded insulating case 1, said case 1 comprising at one of its ends 1a (the only one which can be seen in this figure), compartments 2 in which the connection strips 3 of the switchgear apparatus extend. According to the embodiment illustrated in figures 1 to 3, these compartments 2 are designed to house terminals 4 for connection of the previously mentioned strips 3 to power cables 5. These terminals 4 are formed by blocks 6 fixed onto the strips 3 by means of screws 7 inserted via the rear of the case 1, through two respectively first and second openings 8, 16 provided respectively in the case 1 and in the corresponding strip 3, before being screwed into one of the ends of the corresponding terminal 4. As can be seen more particularly in figure 1, each compartment 2 of the case 1 has associated thereto an opening 8, called the first opening, arranged in the rear part of the case 1 and enabling the passage of two fixing screws of a terminal 4. This opening 8 forms two housings 8a, 8b of appreciably hexagonal shape, joined by a straight part 8c. These two housings 8a. 8b are shaped in such a way as to each receive and allow free rotation of a screw with a hollow-cast round head 9, 10 used for fixing a terminal In figure 4, it can be seen that the connection strips 3 are each connected to a bar 23. In this case, the fixing screws of the bars 23 need to be immobilized in rotation. For this purpose, screws are used presenting a hexagonal head 11. 12, which, when inserted in the openings 8, are immobilized in rotation by the walls forming the limits of the portions of openings 8a, 8b of hexagonal shape. In figures 5 and 6, connection of the strips 3 is performed in disconnectable mode. Thus, the openings 8 provided in the case 1 are designed to each receive the free end 13a of a fixed connecting prong 13, whose shape corresponds to that of the opening 8. Each of the openings 8 provided in the case 1 is blanked off by an insulating cover 19 joined in articulated manner to said case 1 by a hinge 14 integrated in said cover 19. This hinge is fixed to the case by a clip C enabling the cover to remain secured to the case in the open position of said cover. It can also be noted that at the time closing takes place, the cover is closed by means of another clip. The connection operation will be described briefly hereafter according to the type of connection chosen. When connection is performed by means of terminals 4, the covers 19 are moved to the open position (fig-2), then two screws with round heads 9, 10 are inserted in the corresponding opening 8. The screws are then screwed into the terminal 4 by means of a suitable tool, the screw heads rotating freely in the openings 8. The power cables 5 are then inserted in the orifices 22 provided for this purpose in the terminals 4 (fig.3). When connection is performed on a bar 23, two screws with hexagonal heads 11, 12 are previously inserted via the rear of the apparatus D into the corresponding openings 8, 16 of the case 1 and of the strip 3 after the covers 19 have been opened. The screw heads 11, 12 being immobilized in the case 1, fixing of the bar 23 onto the strip 3 is achieved by means of a nut 15. If the disconnectable type connection mode is chosen, the apparatus D is moved in the direction of fixed conductors in the form of prongs 13 so as to insert the ends 13a of said prongs 13 inside the openings 8 of the case 1. Fixing of the prongs 13 onto the strips 3 is achieved by means of a screw 17 inserted via the front of the apparatuses D through the two orifices 16, 8 provided respectively in the strip 3 and the case 1 and screwed into the corresponding end 13a of the prongs 13. Each rigid conductor or prong 13 comprises an end 13a comprising two columns 18, 19 of appreciably hexagonal cross section joined by a cross-member 20 and each comprising a fixing orifice 21 designed to receive said screw 17, said end 13a cooperating with a first opening 8 of corresponding shape of the case 1. It can be noted that in the case where this connection mode is chosen, it is not absolutely necessary for the prong to be immobilized in rotation in the opening and therefore for the shape of the prong to correspond exactly to that of the opening. According to another particular embodiment of the invention, this case comprises in addition a strengthener 24 inserted in each first opening, which presents a slightly enlarged cross section compared to the openings of the previous embodiment in order to improve the resistance of the case in holding the screws. Advantageously, this strengthener 24 is removable so as to enable a fixed rigid conductor of slightly enlarged cross section to be housed when it is extracted from the case. It can be noted that the hexagonal shape of the housings and of the screw heads is given as an example only. Other shapes for the housings and screw heads will naturally be able to be envisaged within the scope of the invention provided that they enable these screws to be blocked in rotation and that they allow free rotation of circular-headed screws. The screws used will advantageously be standardized screws. It can be seen that by means of the invention, switching from one connection mode to the other is performed with the same parts, without any intermediate part. The different electrical isolation distances are ensured by the cover. Connection by bar is achieved in simple manner, a single tool being necessary to perform tightening. The possibility of replacing the standardized screws with others (more or less long) should also be noted. The case of the apparatus fulfills several functions, i.e. supporting the connection strips, isolation of the phases from one another and from the outside, holding the bar connection screws in rotation, the function of cover of the fixing screws, holding the screws before and during installation of the apparatus, and respecting the electrical isolation distances by means of the cover. It can also be noted that the screw cover is held captive due to the use of the integrated hinge. WE CLAIM 1, A case designed for housing an electrical apparatus such as a circuit breaker and comprising, at at least one of its ends, terminal compartments in which there are respectively housed connection strips and means for fixing said strips to external conductors such as a bar, a cable etc., characterized in that these means comprise, for at least one of the previously mentioned compartments (2), at least a first opening (8) provided in the case (1), at least a second opening (16) provided in the connection strip (3) and situated facing the first opening(s) (8), and at least one screw (7) passing through two orifices facing one another provided respectively in the case (1) and in the strip (3) to perform fixing of a conductor (5, 11, 13) onto the connection strip (3), said first opening (8) being shaped in such a way as on the one hand to receive and guide in rotation at least one screw head (9, 10) of circular shape, and on the other hand to block in rotation with respect to the case (1) at least one screw head (11, 12) of suitable non-circular shape. 2. The case according to claim 1, characterized in that the screws (7) with circular heads (9. 10) are designed for fixing terminals (4) onto the connection strip (3). 3. The case according to claim 1 or 2, characterized in that the previously mentioned screws (7) with non-circular heads (11, 12) are designed for fixing bars (23) onto the connection strips (3). 4. The case according to any one of the claims 1 to 3, characterized in that the or each first opening (8) is also designed to receive a fixed rigid conductor (13). 5. The case according to any one of the claims 1 to 4, characterized in that the or each first opening (8) forms at least one housing (8a, 8b) of appreciably hexagonal shape cooperating with at least one screw (11, 12) whose head is appreciably of the same shape. 6. The case according to any one of the foregoing claims, characterized in that the or each opening (8) is closed by an insulating cover (19) joined in articulated manner to the case (1) by a hinge (14) integrated in said cover (19) and fixed to the case by a clip (C). 7. The case according to any one of the foregoing claims, characterized in that the or each rigid conductor (13) comprises an end (13a) comprising two columns (18, 19) of appreciably hexagonal cross section joined by a cross-member (20) and each comprising an orifice (21) for fixing a screw, said end (13a) cooperating with a first opening (8) of corresponding shape of the case (1). 8. The case according to any one of the foregoing claims, characterized in that the case (1) is made at least in part of an insulating material, so as to ensure the relative isolation of the different phases. 9. The case according to any one of the foregoing claims, characterized in that the or each previously mentioned first opening (8) is arranged in the rear part of the case (1). 10. The case according to any one of the foregoing claims, characterized in that it is designed to house a circuit breaker D. 11. The case according to any one of the foregoing claims, characterized in that it 5 comprises in addition a strengthener (24) inserted in the or each first opening (8) presenting a slightly enlarged cross section in order to improve the resistance of the case in holding the screws. 12. The case according to claim 11, characterized in that the previously mentioned 10 strengthener (24) is removable so as to enable a fixed rigid conductor of slightly enlarged cross section to be housed when it is extracted from the case. 13. A case designed for housing an electrical apparatus such as a circuit breaker, substantially as herein described with reference to the accompanying drawings.

Documents:

mas-1998-2242-abstract.pdf

mas-1998-2242-claims duplicate.pdf

mas-1998-2242-claims original.pdf

mas-1998-2242-correspondance others.pdf

mas-1998-2242-correspondance po.pdf

mas-1998-2242-description complete duplicate.pdf

mas-1998-2242-description complete original.pdf

mas-1998-2242-drawings.pdf

mas-1998-2242-form 1.pdf

mas-1998-2242-form 26.pdf

mas-1998-2242-form 3.pdf

mas-1998-2242-form 4.pdf