Patent Application
20130056337
This application claims priority from French patent application serial no. 11/57714 filed Sep. 1, 2011.
The present invention relates to a moving contact-carrying carriage for an electrical cut-off device, said carriage comprising at least one seat arranged to receive a moving contact associated with a return means, and said carriage being intended to be coupled with an actuator mechanism belonging to said device.
The invention also relates to an electrical cut-off device provided with a control module associated with at least one cut-off module corresponding to a phase of an electrical network, this cut-off module including at least one moving contact associated with at least one pair of fixed contacts, said moving contact being carried by a carriage coupled with an actuator mechanism controlled by said control module so as to be moved between at least one switched-off position in which the moving contact is distant from the fixed contacts and the electrical circuit is open, and a switched-on position in which the moving contact is resting on the fixed contacts and the electrical circuit is closed.
To move the moving contacts from the open or switched-off position to the closed or switched-on position in electrical cut-off devices such as switches, fuse switches, commutators, reversing switches, circuit breakers or similar appliances, the moving contacts are arranged on or carried by a carriage. This carriage is generally made of a single molded or injection-molded part out of synthetic or composite material and is used to operate simultaneously the moving contacts of the different cut-off modules that equip a same cut-off device in function of the number of phases of the electrical network. The whole of the constraints suffered by the carriage, such as heating, continuous mechanical stress, occasional high-intensity mechanical stress, etc., lead inevitably to deformations or even breakages of the carriage. Switching several phases with a same moving carriage also poses insulation problems between the phases. These various constraints limit the technical performances of such a carriage.
The present invention aims to remedy these disadvantages by offering a new design for a moving contact-carrying carriage that can be fitted on any kind of electrical cut-off device in which the moving contacts are closed by pressing them on the fixed contacts, this carriage being arranged to bear without deformation both continuous mechanical stress under high temperature conditions, for example of the order of 100° C., and exceptional mechanical stress, in particular in case of contact areas welding, in order to increase the electrodynamic and mechanical endurance of the electrical cut-off device equipped with such carriage.
To that purpose, the invention relates to a carriage of the kind indicated in the preamble, characterized in that it comprises at least one insulating support comprising said seat and at least one supporting structure surrounding said insulating support so as to form around it a load-absorbing belt.
The supporting structure comprises advantageously at least one connecting part intended for coupling said carriage with the actuator mechanism belonging to said device, this connecting part being preferably positioned in a front section of said insulating support and passing transversally through said seat in order to rest on the moving contact on the side opposite to its return means when said moving contact is mounted in said carriage.
In a preferred embodiment, the supporting structure comprises furthermore a metallic profile extending over the lateral sides and on the rear of said insulating support and the connecting part comprises at least one metallic shaft passing through said insulating support and the side ends of said metallic profile.
The insulating support can comprise at least two superposed parts, among which a body in which said moving contact is seated, and a base in which said return means is seated at least partly, said seat extending from said body to said base.
In the preferred embodiment, the carriage comprises several seats arranged in parallel to accommodate several moving contacts insulated from each other, these seats can have different depths so as to offset said moving contacts in space.
If the carriage is symmetrical with respect to a centerline, then the seats are offset two by two symmetrically with respect to said centerline so as to form stages.
Also to that purpose, the invention relates to a cut-off device of the kind indicated in the preamble, characterized in that said carriage comprises at least one insulating support comprising said seat and at least one supporting structure surrounding said insulating support so as to form around it a load-absorbing belt, as defined above.
The present invention and its advantages will be better revealed in the following description of an embodiment given as a non limiting example, in reference to the drawings in appendix, in which:
Referring to
This cut-off device 1 must be able to establish and cut off currents I called normal or fault currents having a value from 0 to 10 In, In being the value of the rated current that can flow continuously through the device. This device must also be able to establish and if necessary cut off short-circuit currents whose value that can reach 100 to 300 times the rated current In, without breakage or deformation of the carriage 8.
The solution of the invention is described in reference to an electrical device 1 whose cut-off modules have a specific internal architecture, which is the subject of another patent application filed simultaneously, but it can of course apply to any internal architecture according to the state of the art. In the example represented in
The solution of the invention is also described in reference to an electrical device whose moving contact is in fact made of a set 5, 5′ of several parallel moving contacts 5A-C, 5A-F offset in space allowing to stagger in time the approach of the moving contacts on the fixed contacts 4, which is also the subject of another patent application filed simultaneously, but it can of course apply to the devices according to the state of the art comprising one or several moving contacts for each pair of fixed contacts. In the example represented in
The lateral moving contacts 5B-C and 5B-F are made each of a conductive part having the shape of a metallic blade that is symmetrical with respect to the centerline A and provided laterally with two contact areas C. They may have identical dimensions or not. They are at least identical two by two symmetrically with respect to the centerline A.
The moving contacts 5A-C, 5A-F of a same set 5, 5′ are carried by a carriage 8 object of the present invention. In the illustrated example, the carriage 8 comprises several separated and parallel seats 80, arranged for receiving the moving contacts 5A-C, 5A-F and insulating them from each other. Each moving contact is associated in its seat 80 with a return means 65, for example in the form of a compression spring, arranged to exert a determined pressing force on the moving contact when it is pressed against the fixed contacts 4 in the switched-on position. The seats 80 have different depths so that the lateral moving contacts 5B-C, 5B-F are offset two by two with respect to the protruding central moving contact 5A and form stages E1, E2, etc. The stroke from one stage to another may be equal or not.
The carriage 8 comprises an insulating support 81 in which the seats 80 are provided, as well as a supporting structure 9 surrounding the insulating support 81 to form around it a load-absorbing belt. In the represented example, the insulating support 81 is made of two superposed parts that define a body 82 in which the moving contacts 5A-C, 5A-F are seated, insulated from each other by the walls of the seats 80, with an axial freedom of movement, and a base 83 on the bottom of which the return means 65 are resting. The seats 80 extend between the base 83 and the body 82 and come out of said body laterally and symmetrically with respect to the centerline A to let the contact areas C stand out. The central seat 80 extends up to the front of the insulating support 81 taking into account the boss 50 that prolongs the central moving contact 5A in order to serve as a spark arrestor. The body 82 and the base 83 are held assembled by said supporting structure 9. Of course, any other embodiment of said insulating support 81 that would allow achieving the same functionality is conceivable.
In the represented example, the supporting structure 9 comprises a preferably metallic flat profile 90 extending over the lateral sides and on the rear of the insulating support 81 like a belt. It furthermore comprises a connecting part 91 in the form of a preferably metallic shaft passing through the insulating support 81 at the front and linked mechanically with the side ends of the profile 90 to close the belt. This connecting part 91 passes transversally through at least one of the seats 80 and preferably the central seat to rest against at least and preferably the central moving contact 5A, on the side opposite to its return means 65. The connecting part 91 forms a joint B2 that allows coupling the carriage 8 with the actuator mechanism 6 as explained below and thus transmits directly the driving efforts of said mechanism, in particular when switching off to open the electrical circuit, to the central mobile contact 5A that is the last leaving the fixed contact 4. Of course, any other embodiment of said supporting structure 9 that that would allow achieving the same functionality is conceivable.
In the represented example, the actuator mechanism 6 of the set 5, 5′ of moving contacts comprises a drive shaft 60 linked in rotation with the handle 20 by means of a (non visible) angle transmission and/or controlled by a second (non represented) element fitted in the square bore 61. A system converting the rotary movement of the drive shaft 60 into a translation movement allows moving the carriage 8 along centerline A. This movement conversion system comprises a couple of jointed rods 62, 63, but any other equivalent means is conceivable. The first rod 62 is fixed to the drive shaft 60 and coupled in rotation with the second rod 63 by means of a first joint B1. The second rod 63 is coupled in rotation with the carriage 8 by a second joint B2 defined by the connecting part 91. The carriage 8 is guided in translation with respect to housing 30 by means of rails, ribs or any other equivalent means in which the protruding ends of the connecting part 91 that form the joint B2 or any other complementary shape are circulating.
This description shows clearly that the invention allows reaching the goals defined, in particular the design of the moving contact-carrying carriage allows dissociating the moving contacts insulation function from the mechanical resistance function of the carriage, and assigning them to two different but complementary parts, adapted to the assigned function as well in the choice of the materials as in their shape. The achieved result is an increase of the technical characteristics of such a carriage and of its lifetime, contributing favorably to prolong the endurance of the electrical cut-off device.
The present invention is not restricted to the examples of embodiment described, but extends to any modification and variant which is obvious to a person skilled in the art while remaining within the scope of the protection defined in the attached claims. The carriage of the invention has been described in reference to a multi-moving contact version, but it can also be provided for a single-moving contact version. In any case, it is necessary to provide one carriage per cut-off module or per phase.
| Number | Date | Country | Kind |
|---|---|---|---|
| 11/57714 | Sep 2011 | FR | national |
