EP1280178B1 - Electrical switching device having a housing consisting of two parts fixed together with staples - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION

The invention relates to a low-voltage electrical switchgear of the type comprising a rigid housing made of insulating synthetic material, housing separable contacts and a mechanism for driving these contacts. More specifically, the invention relates to the method of fixing the parts constituting the housing of such an apparatus.

STATE OF THE PRIOR ART

The housings of multipole switchgear with high ratings are very conventionally constituted of at least two parts, with a base for supporting the power terminals for the electrical connection of the equipment, and at least one cover, the housing delimiting a housing for separable contacts connected to the power terminals and for a drive mechanism of the contacts. The cover generally comprises at least one passage window for operating, controlling or viewing elements of the apparatus. Where appropriate, the cover may be provided with troughs which are housed auxiliaries of the equipment and which are closed by an auxiliary cover which covers all or part of the cover. An apparatus of this type is described for example in the document WO 01/16984 . The fixing of the cover on the base is done by means of fixing screws: the base is provided with threaded holes prolonged by bores of the cover, so that one can introduce and screw the screws starting from the front face of the lid.

When a range of equipment includes both multipole devices of the above type and unipolar devices, and it is desired to take up in the unipolar device all or part of the mechanism, the breaking chambers or the trigger of the multipolar device, it is necessary to provide for the unipolar device a housing of the same general design for multipolar devices, that is to say also composed of a base and a cover. This is the case, for example, unipolar case described in the document WO 01/16986 . The cover then has at the four corners of its front face four holes opening, extended by four threaded holes formed in reinforced walls of the base. These holes allow to introduce screws which serve to fix the lid to the base. Once the screws are mounted, the screw heads are flush with the front of the housing. Such screw mounting poses a problem of space, since the available space on the front of the apparatus is low. In addition, this architecture requires to provide a reinforced structure in the corners of the housing, with enough plastic material to form rigid material wells at the tapped holes. Indeed, in case of overpressure in the device, at the time of the cutting of strong currents, the screws work tearing, which imposes a large screw diameter and a deep thread. The screws must necessarily be arranged in the corners of the housing to free up space in the middle part that houses the mechanism and the contacts. Therefore, the median portion of the seam between the side walls, away from the fastening screws, may deform when subjected to the pressure of the gases produced by the electric arc in the housing during a cut, in particular a short circuit current. This leads either to thicken the side walls to give them more rigidity, or to be satisfied with a poor sealing of the housing. Finally, the assembly of the four screws requires tedious assembly operations.

Also known alternative methods of fixing between two parts of an electrical switchgear housing, especially for small caliber devices, used mainly in electrical terminal distribution boards. Conventionally, the housing of these devices consists of two half-shells that are usually riveted together. To reduce the number of rivets, it has been proposed in the document FR 2,389,221 , affix an adhesive tape to the joint between the half-shells, to increase the strength of the housing. It has also been proposed to replace some rivets with elastic clips, as illustrated in the document FR 2,462,014 . In this document, two rivets are used to secure the half-shells in the rear corners of the housing. These two rivets are completed by two U-shaped elastic clips arranged on the front face, in the front corners, perpendicular to the line of joining of the half-shells. However, these proposals do not replace all rivets. Moreover, it is clear that they concern only weak appliances calibres which, during the break, generate only relatively low overpressures, thus low stresses. It was also proposed in the document EP 860.901 forming on one half-shell resilient hooking tabs cooperating with notches formed in the other half-shell so as to ensure assembly without rivets and without screws. This method of attachment is very advantageous in its simplicity but is not suitable for devices likely to be subjected to internal overpressure, including power switchgear, circuit breakers or switches. Furthermore, it should be noted that the half-shells housings have a geometry fundamentally different from the switchgear housings pedestal and cover, so that the solutions retained for some are not transposable to others. It was also proposed in the document JP 4,242,037 to fix the two parts of a circuit-breaker box using elastic belts surrounding the periphery of the circuit-breaker. Each belt is practically a complete turn of the case. According to a variant, the two ends of each belt are fixed to one another on the front face of the housing. According to another variant, each of the two ends of the belt is fixed by appropriate means to the housing cover. The belts consist either of fiberglass reinforced polyester fabric webs, or of strips of highly extensible polyacetal material, or of a composite product containing nylon and glass or carbon fibers, or else piano strings. In any case, the belts envisaged are flexible and extensible. It is these mechanical properties which make it possible to surround the casing and to ensure the desired cohesion between the two parts of the casing thanks to the stresses generated by the elastic deformation in tension of the belts. The mounting of the belts is not easy because it requires a significant tensioning, hence the use of a machine or a specific tool for mounting force. In addition, as regards the belt whose ends are fixed to the housing, the resulting stresses at the housing at the point of attachment are essentially tangential, which is not very favorable. Finally, belts that are subject to a strong extension, tend to change their elastic characteristics over time, so that after a few years, the behavior of the housing may cause problems.

SUMMARY OF THE INVENTION

The invention therefore aims to overcome the drawbacks of the state of the art, so as to provide a molded case electrical switchgear of the type comprising a base and a cover, the method of fixing between the base and the cover is at both space-saving, simple assembly and a low price.

For this purpose, the subject of the invention is an electrical switchgear according to claim 1.

The clip is external to the case and therefore does not take up space inside the case. The implementation of the clip is very simple. It suffices to position one of the tabs relative to the housing and then to lightly press on the median part of the clip which flexes by elastic deformation and allows the establishment of the second tab. This assembly does not require considerable effort. In addition, the staple in place is not subject to significant deformation, so that its elastic characteristics have no reason to change during the life of the equipment.

Preferably, the securing means further comprise: a second elastic metal clip comprising a median portion extending from the posterior wall to the anterior wall, and extended by an anterior tab folded on the anterior wall and by a folded rear tab; on the posterior wall, ensuring a pinch of the base and the lid. The housing forms a first opposing side wall and a second side wall, the middle portion of the first staple being in contact with the first side wall, the middle portion of the second staple being in contact with the second side wall. the housing is part of a parallelepipedal geometrical envelope having planar lateral geometrical faces tangential to the first lateral wall and to the second lateral wall, the driving mechanism driving the separable contacts in a plane motion along a path parallel to said lateral geometrical faces .

The staples pinch the two opposite sides of the housing. They therefore constitute an outer frame or strapping ensuring stiffening of the housing. The housing walls at the interface with the staples work only in compression, and are not subject to significant shear stresses. If the housing is subjected to a significant internal overpressure caused by an electric arc when a high current is cut inside the housing, the forces at the interface between the housing and the staples are not likely to damage. The box.

Moreover, the small size of the staples makes it possible to arrange them, if necessary, elsewhere than in the corners, and in particular closer to the median part of the side walls. The rigidity of the housing is reinforced, especially at the joint between the side walls of the base and those of the lid.

Preferably, the first side wall has a groove for accommodating the middle portion of the first clip and the second side wall has a groove for accommodating the middle portion of the second clip. The grooves make it possible to hold the staples without the need for a large quantity of plastic material. They restrict access to staples and prevent accidental disassembly.

Advantageously, the housing also forms transverse walls connecting the side walls, the apparatus further comprising electrical power terminals connected to the contacts and opening out of the housing through passage holes formed in the transverse walls. The staples are arranged on the side walls which do not have an electrical connection function, so as not to generate additional space on the transverse walls used for the connections.

According to one embodiment, the side walls have a greater surface area than the transverse walls, especially if the apparatus is unipolar. It is in this case indeed that in practice, the small size of the staples is of the greatest interest, even if the use for multipolar devices is also considered.

Advantageously, the posterior wall has a first posterior notch for accommodating the posterior leg of the first clip, and a second posterior notch for housing the posterior tab of the second clip. Similarly, the anterior wall has a first anterior notch for housing the front tab of the first clip, and a second anterior slot for housing the front tab of the second clip. The notches help to prevent unintentional disassembly.

According to one embodiment, the apparatus further comprises a posterior cover covering at least partially the rear tab of the first clip and the rear tab of the second clip. This posterior cover essentially serves to prevent access to the hind legs of the staples.

According to one embodiment, the apparatus further comprises a front cover provided with a window for the passage of the operating member. This front cover, also called auxiliary cover, may have a guiding function of the operating member. It can also cover open troughs in the cover on the side opposite the base to accommodate signaling or control auxiliaries. On the other hand, it does not have the function of maintaining the mechanism, or of containing the internal pressure of the apparatus.

According to a variant, the front cover at least partially covers the front tab of the first clip and the front tab of the second clip. The front cover then also has the function of preventing direct access to the front legs.

BRIEF DESCRIPTION OF THE FIGURES

• la figure 1 représente une vue en perspective d'un disjoncteur unipolaire selon un mode de réalisation de l'invention ;
• la figure 2 représente une vue du disjoncteur de la figure 1 en coupe longitudinale suivant un plan de coupe II-II ;
• la figure 3 représente une vue du disjoncteur de la figure 1 en coupe transversale suivant un plan de coupe III-III.

Other advantages and features will emerge more clearly from the following description of a particular embodiment of the invention, given by way of non-limiting example, and represented in the accompanying drawings in which:

• the figure 1 represents a perspective view of a unipolar circuit breaker according to one embodiment of the invention;
• the figure 2 represents a view of the breaker of the figure 1 in longitudinal section along a sectional plane II-II;
• the figure 3 represents a view of the breaker of the figure 1 in cross section along a sectional plane III-III.

DETAILED DESCRIPTION OF AN EMBODIMENT

The switchgear apparatus illustrated in the figures is a unipolar low-voltage circuit breaker 10 having a molded case made of insulating synthetic material 12 formed rearwards of a base 14 and towards the front of a cover 16.

The cover 16 has an anterior wall 17 partially covered with an auxiliary cover 18, ridged side walls 19a, 19b and transverse walls 20, 21. The base 14 has in turn a rear wall 22 opposite to the front wall 17 cover 16, side walls 23a, 23b and transverse walls 24, 25. The cover 16 fits into the base 14 with a geometric joint plane located at the edges of the side and transverse walls of the base and the cover, so that the assembled housing is substantially parallelepiped, with two lateral faces 24a, 24b of large dimensions, and two transverse faces 26, 28 relatively narrow and strongly cut. In other words, the housing of the apparatus can be inscribed in a geometrical envelope consisting of a rectangular parallelepiped having its large faces tangential to the side walls 24a, 24b and parallel to the section plane II-II of the figure 2 .

The cover 16 is fixed to the base 14 by means of four elastic clips 30a, 30b, opposite in pairs on the lateral faces 24a, 24b of the housing. Each staple is constituted by a rigid elastic blade having a rectilinear median portion 32a, 32b, extended at one end by a hooked front leg 34a, 34b which has just inserted in an anterior notch 36a, 36b of the lid 16, and at the other end by a rear tab 38a, 38b inserted into a rear notch 40a, 40b formed in the base 14. At rest, the rear leg 38a, 38b is bent a little over 90 ° with respect to the medial portion 32a, 32b. The front notch 36a, 36b opens on the front face 17 and sinks substantially parallel to the side faces 24a, 24b to accommodate the hook which is bent at 180 °. The rear notch 40a, 40b sinks approximately perpendicular to the lateral face 24a, 24b on which it opens, and forms a recess towards the corresponding anterior notch. The front notch 36a, resp. 36b and the rear notch 40a, resp.40b corresponding to the same clip 30a, resp. 30b are connected by a groove 42a, resp. 42b formed in the side walls of the base and the lid. A posterior plate 43 is fixed by clips (or sticking) on the posterior wall 22 so as to form a posterior cover preventing access to the posterior notches. Parallel to the grooves 42a, 42b, the housing also forms semi-cylindrical grooves 44 located at the four corners of the apparatus. At each semi-cylindrical groove 44 corresponds a notch 45.

The cover 16 is provided with a passage window 46 for a lever 88 for operating the mechanism of the circuit breaker, this opening being extended by a corresponding window 47 of the auxiliary cover 18. A movable screen 48 provides a seal between the interior and the door. outside of the housing 12 at the window 46. The auxiliary hood 18 further accommodates a push button 49 for transmitting a trip command to the mechanism. The auxiliary cover 18 is fixed to the cover 16 by screws 50 accessible from the inside of the cover.

The housing 12 houses a breaking subassembly 54, a driving mechanism 56 and a magnetothermal release 58, visible on the figure 2 .

The breaking subassembly 54 consists of a fixed contact 62 electrically connected to a first power connection pad 64, and a movable contact 66 supported by a rotary contact holder 68 and electrically connected to a second connection pad 70. The power connection pads 64, 70 emerge from the housing through the orifices of the transverse walls 24, 26. The contacts 62, 66 are confined within an interrupting chamber 72 containing metal separators 73. intermediate partition 74 made of material with the base 14 and provided with a slot for the passage of the movable contact 66, defines the chamber on the side of the contact holder 68. On the opposite side to this intermediate partition 74, the chamber 72 is closed by a reported partition 76, provided with a through hole 78 for the output of cutoff gases. The other faces of the chamber are constituted by the walls of the base and the housing cover.

The mechanism 56 drives the contact carrier 68 between an open position and a closed position. It comprises a toggle joint consisting of a lower link 80 hinged to the contact gate and an upper connecting rod 82 articulated on a coupling lever 84 driven by a pivoting metal support 86 secured to the actuating member constituted by the handle 88 The engagement lever 84 cooperates with an opening latch 90 controlled by the trigger 58. An energy storage spring, not visible in the figure, is stretched between the support 86 of the handle and the axis of the articulation of the knee pad. The operation of this mechanism, well known per se, is described more precisely in the document FR2783349 which will be referred to for more information. The moving contact 66 is moved by the mechanism parallel to the section plane II-II of the figure 2 .

The device is installed as follows. First, the shut-off subassembly 54, the mechanism 56 and the trigger 58 are placed in the base 14. In parallel, the auxiliary cover 18 is fixed on the cover 16 by means of the screws 50. cover 16 on the base 14. Then is inserted, for each clip 30a, 30b the hook 34a, 34b in the corresponding front notch 36a, 36b, and the clip 30a, 30b is pivoted so as to press against the housing 12, before lightly pressing the middle portion 32a, 32b of the clip. The clip then flexes slightly by elastic deformation, and the rear tab 38a, 38b inserts itself into the posterior notch 40a, 40b, to remain therein retained in the recess, simultaneously ensuring the plating of the medial portion. 32a, 32b of the clip at the bottom of the groove 42a, 42b. The groove 42a, 42b is deep enough so that, once mounted, the clip 30a, 30b remains recessed relative to the side face 24a, 24b of the housing. Thus, the staple 30a, 30b does not leave a catch, so that there is no risk of involuntary extraction of the staple by 12. Finally, the access to the rear notches 40a, 40b is protected by mounting the plate 43.

Once the staples are mounted, it is possible to fix the device on a switchboard. It uses for this purpose removable eyelets 100 provided with a lateral tongue 102 of fixing being inserted into the slot 45 of the cover and screws (not shown) which are inserted into the eyelets 100 and which is screwed into a wall of the painting. The screws are guided by the semi-cylindrical grooves 44 and held in position by the eyelets 100.

In order to disassemble the staples, it is first necessary for the apparatus to be detached from the board so that the rear wall 22 of the housing 12 can be accessed, to remove the rear plate 43 and, for each staple 30a, 30b, extracting the rear tab 38a, 38b from the rear notch 40a, 40b with a tool.

Naturally, various modifications are possible.

The number of staples can be any, provided there is at least one closing one side of the housing. We can indeed consider closing the opposite side by screws or hinge.

In the case where there is at least one staple on each side face, the staples do not necessarily face two by two. Moreover, the number of staples is not necessarily even.

Complementary staples can also be envisaged on the transverse faces of the housing. This will be particularly useful when the housing is wide, for example when it is a multipolar appliance box.

The shape of the staples and notches may be arbitrary provided that the two parts of the housing are pinched.

According to a variant not shown, it would be possible to envisage a rear notch providing the mirror image of the notch of the embodiment of the embodiment shown in the figures, that is to say, sinking deeply in the direction parallel to the side face. It would then be possible to envisage a posterior leg in the form of hook, this requires a mounting by plastic deformation of the end of the staple, using a tool.

It is also conceivable to provide an anterior notch which has the same shape as the posterior notch of the embodiment shown in the figures, the hook being replaced by a front tab folded approximately 90 ° or 100 °, as the hind leg.

According to a variant, it is possible to arrange between the cover and the auxiliary cover housing for auxiliaries of the apparatus. This will be possible in particular in the case of a multipole apparatus, in which the space occupied by the mechanism at the central pole, corresponds to the level of the lateral poles to a free space.

According to another variant, it is possible to extend the auxiliary cover so that it covers the front legs.

According to another variant, the auxiliary cover may be omitted.

Furthermore, it is possible to provide a reduced cover to a plate forming the front wall, the lateral faces of the housing being entirely constituted by the side walls of the base. It is also possible to form a housing in three parts, with a base reduced to a bottom, an intermediate envelope without back wall and without cover constituting the side and transverse walls, and a reduced cover to a front wall.

The joystick can be replaced by a push button or any other operating member allowing an operator to directly maneuver the mechanism.

The mechanism can be of any type allowing a plane movement of the moving contact, whether this movement is rotary, translational or compound. It can also be a mechanism simultaneously driving the two contacts in opposite directions.

Claims (10)

1. An electrical switchgear apparatus comprising

   - a case (12) comprising:

   - a base (14) forming a rear panel (22),

   - a cover (16) forming a front panel (17) that is opposite the rear panel (22) and is provided with a pass-through opening (46),

   the case forming a first side panel (24a) and an opposite second side panel (24b) and forming transverse panels (26, 28) joining said side panels, the side panels (24a, 24b) having a larger surface than the transverse panels (26, 28);

   - fixing means (30a, 30b) performing securing of the cover (16) with respect to the base (14);

   - separable electrical contacts (62, 66) contained inside the case (12) between the front panel (17) and the rear panel (22);

   - a drive mechanism (56) of the separable contacts, contained inside the case (12) and equipped with an operating element (88) passing through the passage (46) in the cover to the outside of the case (12);

   characterized in that the fixing means (30a, 30b) comprise at least:

   - a first flexible metal clip (30a) comprising a middle part (32a) extending from the rear panel (22) up to the front panel (17) and extended by a front lug (34a) folded over onto the front panel and by a rear lug (38a) folded over onto the rear panel (22), performing gripping of the base and cover, the middle part (32a) of said at least a first clip being in contact with the first side panel (24a).
2. The electrical switchgear apparatus according to claim 1, characterized in that the fixing means further comprise: a second flexible metal clip (30b) comprising a middle part (32b) extending from the rear panel (22) to the front panel (17) and extended by a front lug (34b) folded over onto the front panel and by a rear lug (38b) folded over onto the rear panel (22), performing gripping of the base and cover, the middle part (32b) of the second clip being in contact with the second side panel (24b).
3. The electrical switchgear apparatus according to claim 2, characterized in that the case (12) is situated in a parallelepipedic geometric envelope having flat geometric side faces tangential to the first side panel and to the second side panel, the drive mechanism (56) driving the separable contacts in a flat movement along a trajectory parallel to said geometric side faces.
4. The electrical switchgear apparatus according to claim 3, characterized in that the first side panel (30a) comprises a groove (42a) to house the middle part (32a) of the first clip and the second side panel (30b) comprises a groove (42b) to house the middle part (32b) of the second clip.
5. The electrical switchgear apparatus according to claim 3 or 4, characterized in that the apparatus further comprises electrical power terminals (64, 70) connected to the contacts (62, 66) and opening out on the outside of the case (12) via passage openings formed in the transverse panels (26, 28).
6. Electrical switchgear apparatus according to any one of the claims 2 to 5, characterized in that the rear panel (22) comprises a first rear notch (40a) to house the rear lug (38a) of the first clip, and a second rear notch (40b) to house the rear lug (38b) of the second clip.
7. The electrical switchgear apparatus according to any one of the claims 2 to 6, characterized in that the front panel (17) comprises a first front notch (36a) to house the front lug (34a) of the first clip, and a second front notch (36b) to house the front lug (34b) of the second clip.
8. The electrical switchgear apparatus according to any one of the claims 2 to 7, characterized in that the apparatus further comprises a rear cover plate (43) at least partially covering the rear lug (38a) of the first clip and the rear lug (38b) of the second clip.
9. The electrical switchgear apparatus according to any one of the claims 2 to 8, characterized in that the apparatus further comprises a front cover plate (18) provided with a window (47) for passage of the operating means (88).
10. The electrical switchgear apparatus according to claim 9, characterized in that the front cover plate (18) at least partially covers the front lug (34a) of the first clip and the front lug (34b) of the second clip.

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