AU686396B2

AU686396B2 - Multipole differential circuit breaker

Info

Publication number: AU686396B2
Application number: AU27234/95A
Authority: AU
Inventors: Patrick Guillon; Didier Sibille
Original assignee: Schneider Electric SE
Current assignee: Schneider Electric SE
Priority date: 1994-07-29
Filing date: 1995-07-27
Publication date: 1998-02-05
Anticipated expiration: 2015-07-27
Also published as: EP0694938A1; CN1120727A; EP0694938B1; DE69504258D1; FR2723251B1; ZA956163B; ATE170328T1; DE69504258T2; CN1043100C; FR2723251A1; AU2723495A; ES2121320T3

Abstract

The modular circuit breaker includes a section (20) which slots into a wire holder in the side of the circuit breaker. The section is made up of two click fit sections (21,22), one of which (21) is shorter than the other. The sections are joined forming a bridge at the rear. Pushing the click fit sections into channels (15a,15b) engages a shoulder on one channel first, and forms the wire connection. Pushing into the second position locks the wires in place. The wall (23) between the two channels has a brittle zone (24) so that it comes loose if the section is removed from the channel. <IMAGE>

Description

MULTIPOLE DIFFERENTIAL CIRCUIT BREAKER The present invention relates to a multipole circuit breaker formed by modular side-by-side assembly of a differential trip device unit and a circuit breaker unit, and by electrical connection of these two units by means of connecting conductors connected, at the time said assembly takes place, to connection terminals performing the electrical connection of said two units, this circuit breaker being provided with a terminal cover arranged to mask said connection terminals when the two units are assembled and their electrical connection is achieved, and provided with at least one opening for engagement of locking means.

A circuit breaker of this kind is described in the European Patent application published under the number 0,375,568. This circuit breaker comprises a terminal cover which is associated to a locking bolt through which a sealing wire passes. The terminal cover is fitted after the circuit breaker unit and the differential trip device unit have been assembled to ensure that the apparatus is tamperproof. Using a sealing wire to achieve this tamperproof function is a drawback for the user, as the sealing wire is not supplied with the apparatus.

The present invention proposes to overcome these shortcomings by adopting integrated locking means fulfilling the functions of masking the terminals and of rendering the apparatus tamperproof.

The multipole differential circuit breaker according to the invention is characterized in that said locking means are arranged to be pre-assembled on the terminal cover and comprise tamperproof means designed to generate a permanent visible trace in case of disassembly.

Advantageously, said locking means can comprise a strap composed of at least one clip-on element fitted in a suitable opening of the terminal cover. This strap can comprise two clip-on elements of different lengths, arranged parallel to one another and connected by a connecting strip, or can be formed by a single clip-on element, the terminal cover comprising a single opening arranged so that, in the locking position of said strap, said element is completely imbedded in said opening.

The invention will become more clearly apparent with reference to the description of advantageous embodiments given as nonrestrictive examples only, and to the appended drawing in S" which e* Figure 1 represents a perspective view illustrating the circuit breaker according to the invention.

Figures 2, 3 and 4 represent partial views of a first embodiment of the locking means in three successive phases of their fitting, and Figures 5, 6 and 7 represent partial views of a second embodiment of the locking means in three successive phases of their fitting.

With reference to figure 1, the multipole differential circuit breaker 10 represented comprises a circuit breaker unit 11 and a differential trip device unit 12, these two units being of the modular type, assembled side by side and electrically connected, at the time said assembly takes place, by connecting conductors connected on the one hand to connection terminals 13 of the circuit breaker unit and on the other hand to non-visible terminals of the differential trip device unit.

A terminal cover 14 is fitted onto a zone of the circuit breaker unit in such a way that access to said connection

I

terminals 13 is masked when the two units are assembled and their electricl. connection made. This terminal cover is provided with at least one opening 15 and in the present case with two openings 15a and 15b for engagement of locking means 16. When pushed in the direction of the arrow A, these locking means are arranged to engage via the openings 15a, 15b and to be imbedded in a recess provided for this purpose in the body of the circuit breaker unit. In this way the terminal cover cannot be removed by movement in a direction (arrow B) perpendicular to that of the arrow A.

The shape and function of the locking means will be described in greater detail with reference to figures 2 to 4 illustrating a first embodiment and to figures 5 to 7 illustrating a second embodiment of said locking means, in the different successive positions which they occupy during their fitting. These locking means are arranged to be able to be pre-assembled on the terminal cover and are provided with circuit breaker tamperproofing means, whose function is to prevent the terminal cover from being removed without leaving a permanent visible trace. In other words, any removal of the terminal cover enabling access to the terminals 13 results in an indelible trace which proves that disassembly has been performed.

Figure 2 represents a plane view of the first embodiment of the locking means. These means are formed by a strap essentially comprising two clip-on elements 21 and 22 arranged appreciably parallel to one another and connected at one of their ends by a connecting strip 23 weakened in a zone of lower resistance 24. The two clip-on elements 21 and 22 are of different lengths. Their free ends are presented in the form of two branches respectively 21a, 21b and 22a, 22b, which are separated by an elongated central slot 21c, 22c, which gives these branches a certain flexibility. In addition, each of these branches comprises a lateral nose 25a, 25b, designed to I cooperate with a shoulder respectively 26a, 26b (figure 3), arranged in the thickness of the wall of the terminal cover inside the openings 15a and In a first phase of fitting of the locking means, illustrated by figure 3, the strap 20 is pre-assembled in the openings and 15b of the terminal cover, which are arranged to receive respectively the two clip-on elements 21 and 22. In the position represented by the figure, the clip-on element 22b has passed through the greatest part of the opening notably the narrower central part of this opening. To enable its penetration into this narrower central part, the end of this element, notably the external edges of the branches 22a and 22b, is rounded and defines a sort of bearing ramp which, in cooperation with the walls of the terminal cover surrounding the opening, performs flexion of these branches moving them towards one another. When the engagement of the clip-on element is sufficiently advanced, the noses overshoot the corresponding shoulders 26b, which releases the two branches which resume their initial position due to their flexibility. In this position, which can be called the preassembly position, the strap 20 is pre-assembled on the terminal cover, but is not yet performing its locking function due to the fact that the end of the clip-on element 22, which is the longer one, does not reach beyond the rear wall 27 of the terminal cover 14. Pre-assembly is on the other hand achieved due to the fact that this strap can no longer be removed by simply pulling it in the direction of the arrow C out of the openings of the terminal cover, as the noses are bearing against the shoulders 26b. It can moreover be noted that the clip-on element 21, which has the same geometry as that of the clip-on element 22, is engaged in the opening the branches 21a and 21b, which form its end, being held tight due to the noses 25a bearing on the internal wall of this opening.

With the terminal cover fitted, if the operator engages the strap 20 completely to the bottom of the openings, the clip-on element 22 is inserted, via its free end, into a recess (not represented) of the circuit breaker unit, thus preventing removal of the terminal cover. When this strap is pushed right to the bottom as represented in figure 4, the clip-on element 21 is fully engaged in the opening 15a and the noses 25a are retained by the shoulders 26a so that the strap is locked in the locking position.

The two clip-on elements therefore each have a distinct role.

The element 22 firstly enables pre-assembly of the strap on the terminal cover to be achieved. Then, this element achieves locking of the terminal cover on the circuit breaker unit. The element 21 has the function of locking the strap in the locking position and of preventing voluntary or accidental removal of the strap. Finally, the connecting strip 23 provided with the weakened zone 24 has the function of ensuring that the system is tamperproof. For if, in spite of the strap being locked, an operator wants to unlock the terminal cover, he is forced to break the strip 23 to disunite the two clip-on elements 21 and 22, to remove the element 22 to the position represented by figure 3 and to leave the element 21 which is locked in place. This breaking of the connecting strip constitutes a permanent visible trace which proves that disassembly of the terminal cover has taken place.

The weakened zone 24 and the connecting strip thereby constitute said tamperproof means of said locking means.

Figures 5 to 7 illustrate a second embodiment wherein the strap performing locking is formed by a single clip-on element which presents a geometrical shape appreciably identical to that of the clip-on elements 21 and 22. It in fact comprises at its end two branches 31a, 31b separated by an elongated slot 32.

To enable a pre-assembly position of the clip-on element 30 to be achieved in a suitable opening 33 of the terminal cover 14, the branches 31a, 31b comprise two lateral noses 34 which cooperate, as shown by figure 6, with two shoulders arranged in the side walls of the opening 33. When the operator wants to lock the terminal cover, he pushes the element 30 right ip to the bottom, so that its end penetrates into a recess (not represented) of the circuit breaker. In this position, illustrated by figure 7, the rear end 36 is completely imbedded in the opening of the terminal cover. The element 30, which constitutes the locking strap can therefore only be removed with a pointed tool, such as for example a screwdriver or similar, which has to be engaged between the wall of the opening and the rear end 36, which necessarily leaves an indelible trace proving that the terminal cover has been disassembled.

In both cases, the object aimed for has been achieved, so that the invention fulfils its objectives.

Claims

1. A multipole differential circuit breaker formed by modular side-by-side assembly of a differential trip device unit and a circuit breaker unit, and by electrical connection of these two units by means of connecting conductors connected, at the time said assembly takes place, to connection terminals performing the electrical connection of said two units, this circuit breaker being provided with a terminal cover arranged to mask said connection terminals when the two units are assembled and their electrical connection is achieved, and provided with at least one opening for engagement of locking means, wherein said locking means are arranged to be pre-assembled on the terminal cover and include tamperproof means designed to generate a permanent visible trace in case of disassembly, said locking means including a strap formed by at least one clip-on element fitted in a suitable opening of the terminal cover.

2. The circuit breaker according to claim 1, wherein said strap includes two clip-on elements of different lengths, arranged parallel to one another and connected by a connecting strip.

3. The circuit breaker according to claim 2, wherein said connecting strip includes a weakened zone.

4. The circuit breaker according to claim 2, wherein each of the two clip-on elements have a free end formed by two branches, separated by an elongated central slot, each branch being provided with a lateral nose cooperating with a shoulder arranged in the terminal cover to define respectively pre-assembly and locking positions of the strap.

The circuit breaker according to claim 4, wherein the lengths of the two clip-on elements are determined in such a way that, in an intermediate phase, the two lateral noses of the longer element are bearing on the shoulders and that, in a final fitting phase, the lateral noses of the shorter element are bearing I ~AllOslPI AQ-rr~-~Irrr~l 8 on the shoulders.

6. The circuit breaker according to claim 1, wherein said strap includes a single clip-on element, the terminal cover including an opening wherein said element is completely embedded in the locking position.

7. The circuit breaker according to claim 6, wherein said clip-on element includes two end branches separated by an elongated central slot, each of these branches being provided with a lateral nose arranged to cooperate with a shoulder arranged in said terminal cover so as to define a pre-assembly position.

8. The circuit breaker according to claim 7, wherein each clip-on element includes two rounded ends arranged on the external edges of the branches. SDATED this 10th day of October, 1997 SCHNEIDER ELECTRIC SA WATERMARK PATENT TRADEMARK ATTORNEYS 290 BURWOOD ROAD HAWTHORN VICTORIA 3122 AUSTRALIA 0 o0 i ABSTRACT MULTIPOLE DIFFERENTIAL CIRCUIT BREAKER The present invention relates to a multipole differential circuit breaker formed by modular assembly of a circuit breaker unit and a differential trip device unit. This assembly is provided with a terminal cover (14) provided with locking means. These locking means are formed by a strap (20) formed by two clip-on elements (21 and 22) connected by a connecting strip (23) provided with a weakened zone (24) The two clip-on elements (21 and 22) have different lengths and distinct functions. The element (22) is, in a first position, designed to enable pre-assembly of the strap on the terminal cover and, in a second position, designed to perform locking of this terminal cover. The element (21) is designed to perform locking of the strap in its locking position. Removing the strap necessarily leaves a permanent visible trace. Figure 3 r 1 I-