EP0520914B1 - Casing for electric apparatus - Google Patents

Description

The present invention relates to a housing for electrical equipment, in particular for a circuit breaker or a circuit breaker auxiliary, according to the preamble of claim 1.

Conventional boxes intended to contain electrical equipment generally consist of two molded elements of conjugate forms constituting a casing and a cover and which delimit an internal compartment when they are assembled. The electrical equipment is made up of a certain number of parts which are mounted in the casing. These parts of the electrical equipment are correctly assembled and positioned in the casing only when the cover is assembled to the casing. In fact, certain parts of the electrical apparatus are adapted to come to be mounted on particular elements of the casing and / or of the cover.

It follows from this that if the electrical equipment requires a particular intervention when it is mounted, this intervention can only be carried out after having assembled the cover and the casing, that is to say after having closed the housing. . For example, it is conventional to carry out an initial adjustment of a bimetal thermal trip device in a circuit breaker and to carry out an initial test of correct operation of the circuit breaker. It is also conventional to carry out an initial adjustment and an initial test of correct operation of a circuit breaker control auxiliary.

To carry out such interventions on an electrical apparatus, it is known to arrange in the casing and / or in the cover of the housing at least a hole which allows the passage of a tool or an instrument intended to carry out the intervention on the electrical apparatus when this one is assembled in the box which is closed. For example, to carry out the initial adjustment of a thermal trip device of a circuit breaker, you can pass a screwdriver through a hole made in the housing in order to turn a adjusting screw of the thermal trip device which is located in The box.

It has long been apparent that such interventions on electrical equipment mounted in a housing present certain difficulties which we will now describe. The parts which constitute the electrical equipment are correctly assembled and positioned in the housing only when the cover is not only mounted on the casing but also rigidly fixed to the casing. Simply placing the cover on the casing is dangerous because it can be easily removed and parts of the electrical equipment fall down. In addition, if you still manage to make an adjustment or intervention on the electrical equipment mounted in a housing whose cover is simply placed on the housing, this adjustment may be distorted when rigidly fixed thereafter the cover on the casing. This misadjustment results from deformations which occur during tightening or blocking of the cover on the casing obtained by the fixing means.

If the means of fixing the cover to the casing is of the non-removable type, it is no longer possible to change a part of the electrical equipment after the intervention intended to carry out the initial adjustment or the initial test of correct operation. However, it appeared that it is frequently during this initial intervention that one can notice certain defects of operation of the electrical equipment and, if the cover has been fixed to the housing in a non-removable, that is to say non-removable, manner, the defective electrical equipment is then irreparable and must be discarded. This is a waste, especially in the case of complex electrical equipment which consists of a large number of parts. If the housing is removable, it is possible to reopen the cover and simply change the defective part of the electrical equipment before closing the cover, fixing it to the housing and carrying out a new adjustment or test intervention. It is for this reason that it has already been proposed, moreover, to use a housing the cover of which can be fixed to the casing using a removable fixing means. The removable fastening means used up to now is of the screw type as described in document DE-A-2 128 057. More particularly, it is known to use a housing in which an assembly means is provided. temporary cover on the housing, this temporary assembly means consisting of a screw passing through the cover and being screwed into a blind hole of a socket formed in the housing. In this case, the housing further comprises other non-removable definitive assembly means using, for example, rivets, ultrasonic welding or snaps. The removable temporary assembly means must be sufficiently effective to allow the initial intervention on the electrical equipment to be carried out correctly, for example an adjustment or a test of correct operation. It is understood that the fact of starting by assembling the cover on the casing using the removable temporary assembly means which uses a screwing means leads to a complication of the housing and leads to an additional mounting operation, since it is necessary to perform both a provisional assembly and a final assembly.

In addition, it is not in principle desirable to assemble the box using only a removable assembly means because it is preferable to be able to make available to the public non-removable or tamper-proof electrical equipment for reasons of liability. and well known security.

An object of the invention is to provide a housing for electrical equipment, this housing being provided with a removable temporary assembly means and with a definitive non-removable assembly means, these two assembly means being of a design simpler than that of the assembly means used in previously known housings.

Another object of the invention consists in providing such a box in which the operations making it possible to carry out the provisional assembly and the final assembly are simpler to carry out than for the boxes known previously.

The invention therefore relates to a box for electrical equipment, in particular for a circuit breaker or a circuit breaker auxiliary, consisting of two half-shells adapted to come against one another in order to assemble to define an internal compartment.

The housing according to the invention is characterized in that one of the half-shells comprises at least one male part of frustoconical shape or of pyramid trunk and in that the other half-shell comprises at least one female part of form combined with the shape of said male part, the positioning of the male and female parts on the half-shells being arranged so that each male part engages in a corresponding female part by constituting a removable lock in a first position, and a non-removable lock in a second assembly position, the two half-shells being closer to each other in said second position, and that the angle of inclination of said conjugate parts with respect to the longitudinal direction of approximation of the half -shells is between one and ten degrees.

• La figure 1 représente une vue partielle en coupe d'un boîtier selon l'invention dans une position désassemblée ;
• La figure 2 représente pareillement le même boîtier que celui de la figure 1 dans une position d'assemblage provisoire ;
• La figure 3 représente pareillement le même boîtier que celui de la figure 1 dans une position d'assemblage définitif ;
• La figure 4 représente une demi-coquille d'un boîtier selon l'invention, en vue en plant montrant son côté interne ; et
• la figure 5 représente l'autre demi-coquille d'un même boitier selon l'invention, en vue en plan montrant son côté interne.

The invention will emerge more clearly from the description which follows of an embodiment of the invention, given by way of example, and represented in the appended drawings, in which:

• Figure 1 shows a partial sectional view of a housing according to the invention in a disassembled position;
• Figure 2 similarly shows the same housing as that of Figure 1 in a provisional assembly position;
• Figure 3 similarly shows the same housing as that of Figure 1 in a final assembly position;
• Figure 4 shows a half-shell of a housing according to the invention, in plant view showing its internal side; and
• Figure 5 shows the other half-shell of the same housing according to the invention, in plan view showing its internal side.

In the figures, a housing 10 consists only of two parts 12, 14. The part 12 forms a first half-shell which constitutes a casing and 1 piece 14 forms a second half-shell which constitutes a cover. The two half-shells 12, 14 are each produced by a molding in one piece, preferably made of plastic. The two half-shells 12, 14 can have a similar general shape but can also have different shapes or dimensions since one constitutes a casing and the other a cover.

The lower half-shell 12 has a bottom 16 and side walls 18 which together define an internal volume. The upper half-shell 14 also includes a bottom 20 and side walls 22 which together define another internal volume. When the two half-shells are assembled, the internal volumes of the two half-shells form a single compartment 23 which is intended to receive and protect the parts constituting an electrical apparatus (not shown). The outer edges of the side walls 18, 22 of the two half-shells 12, 14 each have mating surfaces 24, 26 allowing precise fitting of one half-shell on the other. The surface 24 is perpendicular to the bottom 16 and is directed outwards. The surface 26 is perpendicular to the bottom 20, is directed inward and comes to surround the surface 24 and slide on it.

The lower half-shell 12 further comprises at least one pillar 28 of cylindrical shape connected to the bottom 16 and extending perpendicular to the bottom 16 inside the compartment 23, so that its free end 30 is directed towards the outside towards the other upper half-shell 14 when the latter comes to assemble. The pillar 28 comprises an axial blind hole 32 opening at the free end 30. The blind hole 32 has a frustoconical shape whose cone half-angle is very weak, between 1 and 10 degrees. The truncated cone widens outwards, that is to say towards the free end 30 of the pillar.

It is understood that a geometric shape of a trunk of a pyramid (whose cross section is polygonal) could be used. The truncated cone shape may be preferred when it turns out to be simpler to produce.

The upper half-shell 14 has a protuberance 34 connected to the bottom 20 and extending perpendicular to the bottom 20 inside the compartment 23, so that its free end 36 is directed outwards in the direction of the another upper half-shell 14 when the latter comes to assemble. The protrusion 34 has a frustoconical shape, the cone half-angle of which is substantially equal to that of the blind hole 32, so that the external surface of the protuberance 34 and the internal surface of the blind hole 32 have the same geometric configuration, c that is to say that the protuberance 34 and the blind hole 32 have conjugate shapes.

When the upper half-shell 14 is assembled on the lower half-shell 12, the protuberance 34 begins to engage in the hole 32 before the surfaces of conjugate shapes 26 and 24 come into contact with one another. other. This initial position corresponds to that shown in Figure 1. In this position, the two half-shells are not integral with one another.

It is then necessary to bring the two half-shells 12, 14 closer together, which causes the effective protrusion 34 to engage in the blind hole 32 and, simultaneously, the interlocking of the conjugate forms 24 and 26 formed on the walls. side 12, 14 of the two half-shells. After having thus brought the two half-shells 12, 14 together, the housing is in a first determined assembly position which is removable (or removable), as shown in FIG. 2. In this removable assembly position, a fitting is produced with a slight tightening of the protuberance 34 in the blind hole 32. In this assembly position, if the half-shells 12 and 14 are pulled in the direction of their distance, one of the 'other, one easily obtains the extraction of the protuberance 34 out of the blind hole 32 because the tightening of these two parts is weak. This slight tightening is obtained from the fact that, when the two half-shells are in this first assembly position, slight interference is provided between the diameters of the elements 32 and 34 at their contact points. Consequently, when the two half-shells 12, 14 are thus assembled, a removable temporary assembly is obtained.

In this removable temporary assembly position (FIG. 2), it is possible to carry out, in a conventional manner, a particular intervention on the electrical equipment contained in the housing, for example an adjustment operation or a test of correct operation.

One can provide a known means (not shown) for stably maintaining the two half-shells in the removable position, so that when a person assembles the housing it safely brings the two half-shells in this removable position. This means may conventionally comprise an elastic locking element linked to a half-shell and coming to cooperate with a conjugate element linked to the other half-shell.

When this intervention on the electrical equipment has been carried out, if a test reveals a malfunction of the electrical equipment, the housing can be reopened to carry out another intervention on the electrical equipment, for example to change a defective part. The assembly of the housing can be carried out again by bringing the two half-shells 12, 14 again into the removable temporary assembly position shown in FIG. 2. If the test reveals that the electrical equipment is working properly, it is then necessary to carry out a final, non-removable assembly of the housing. For this, it suffices to exert on the two half-shells 12, 14 a greater effort to bring the two half-shells closer together which then causes a greater interlocking of the protuberance 34 in the blind hole 32 until bearing surfaces 38, 40 facing each other formed respectively on the side walls 18, 22 of the two half-shells abut one on the other, as shown in FIG. 3. In this second position, the force fitting of the protuberance 34 into the blind hole 32 causes these two parts to be tightened very significantly, which results from the cone angle of the conjugate surfaces. This tightening is made all the more effective when the cone angle is relatively small and when, when the protrusion 34 is almost completely engaged in the blind hole 32, the free end 36 of the protrusion 34 comes close to the bottom 42 of the blind hole 32. In this position, significant interference between the diameters of the blind hole and the protuberance causes a very large clamping force. It follows from this that, if a pull is exerted on the two half-shells 12, 14 to separate them from one another, the significant tightening of the pillar 28 on the protuberance 34 is opposed effectively at this traction and this tightening ensures an effort to maintain the protuberance 34 in the pillar 28 which is greater than the limit of tensile strength of the base of the protuberance 34. Consequently, if one pulls too hard on the two half-shells, the protuberance 34 or possibly the pillar 28 is ruptured without thereby causing the protuberance 34 to be extracted from the pillar 28.

This assembly is therefore final and inamobile, that is to say it constitutes an assembly which is commonly called inviolable. In other words, the opening of a case which has been definitively assembled can only be carried out by causing a certain rupture of the parts which can be seen later easily and which prohibits any practical reassembly of the housing.

In FIGS. 4 and 5, one can see respectively one and the other of the two half-shells 12, 14 of the housing 10, seen in plan so as to show their inner side. There are respectively the protrusions 34 on the half-shell 14 and the corresponding pillars 28 on the half-shell 12. These male elements 34 and female 28 are preferably distributed over the half-shells, for example in the vicinity of each corner, so as to ensure good relative positioning of the two half-shells and an effective tamper-evident assembly of the housing thus obtained.

Claims (1)

1. A casing for an electrical switchgear device, notably for a circuit breaker or a circuit breaker auxiliary, made up of two half-shells (12, 14) designed to come up against one another to be assembled to define an internal compartment,
   characterized in that one of the half-shells (14) comprises at least one male part (34) in the shape of a frustum or a pyramid trunk and that the other half-shell (12) comprises at least one female part (32) of conjugate shape to the shape of said male part (34), the positioning of the male (34) and female (32) parts on the half-shells (12, 14) being arranged so that each male part (34) engages in a corresponding female part (32) constituting a removable locking in a first position, and an unremovable locking in a second assembly position, the two half-shells (12, 14) being closer to one another in said second position, and that the angle of incline of said conjugate parts (32, 34) with respect to the longitudinal direction of movement of the half-shells (12, 14) towards one another is comprised between one and ten degrees.

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