FR2550002A1 - CONTACT GROUP FOR ELECTRICAL EQUIPMENT - Google Patents

Abstract

THE INVENTION CONCERNS A CONTACT GROUP 10 FOR ELECTRICAL APPLIANCES WITH A FIXED CONTACT WALL 11 AND A MOBILE CONTACT WALL 12. BETWEEN THE TWO WALLS IS INTERPOSED AN ELASTIC BLADE 13. IN ORDER TO GUARANTEE A PERFECT AND CONSTANT CONTACT WITHOUT THAT EXTREMELY NARROW EXECUTION TOLERANCES ARE NECESSARY, AN ELASTIC CONTACT BLADE 13 HAVING A LONGITUDINAL DIMENSION 14 IS PROPOSED IN A SEAT 19 OF THE FIXED CONTACT WALL 11, PAIRS OF DIVERGENT APPENDICES FOLDED THROUGH TRANSVERSALLY FROM THE SAID SIDE 14, EACH INCLUDING AN INCLINED RAMP 16 CONNECTED IN ARC 17 TO A SECOND RAMP 18 INCLINED IN OPPOSITE DIRECTION. THE ARC CONNECTION 17 OF THE APPENDICES ELASTICALLY SUPPORTS THE CONTACT SURFACE 23 OF THE MOBILE WALL 12. APPLICATION TO CONTACT GROUPS FOR ELECTRICAL APPLIANCES, SUCH AS SWITCHES.

Description

255 C 002

  The present invention relates to a contact group for

  electrical apparatus, such as switches.

  In particular, the present invention relates to contact groups for electrical apparatus for supporting the passage of high intensity currents which comprise a fixed contact wall on which slides a movable contact wall with the interposition of one or more contact blades. Normally anchored to the fixed wall The two contact walls 10 and the blades may be, for example, planar or cylindrical The relative movement between the

  two contact walls determines, in known manner, the opening or closing of the contact group.

  The known contact blades consist of a metal strip having a series of contact fins formed by means of parallel transverse incisions and folded relative to the plane of the strip itself. The fins adhere elastically against the two contact walls. fixed and

  mobile, thus creating a stable contact for the passage of the current.

  It is recognized, however, that contact groups using such blades require a high degree of precision in both the fixed contact wall and the movable contact wall in order to maintain in close tolerance the gap between them. ci in which is contained

  the metal blade The latter must also be carried out correspondingly in a close tolerance of execution.

  Indeed, variations in the value of the distance between the two contact walls and in the folding curve of the blades of the contact blade result in corresponding variations both in the internal resistance and in the

  the sliding force of the contact group.

  If the realization is not of maximum precision, a series of contact groups produced with the same structure could have different technical characteristics.

each other.

  In addition to the problem of precision of execution, that a lack of equilibrium in the parallelism of the relative movement between the two contact walls could, in the long run, cause permanent deformations in the highly stressed vanes to have an irreversible decrease in

  contact points with obvious consequences.

  The object of the present invention is to obviate the aforementioned drawbacks of known contact groups.

  This object is achieved by producing a contact group for 10 electrical devices comprising a fixed contact wall on which slides a movable contact wall with the interposition of at least one elastic contact blade between two respective parallel contact surfaces of said two walls. characterized by the fact that said blade comprises a central longitudinal center, from which wing-shaped appendages each successively consisting of a first and a second segment connected in an arc start. arc resiliently pressing on one of said two mating surfaces, the end portion of said second segments resiliently pressing on the other of said two mating surfaces, said center rib being stably joined in a corresponding seat of one of said two mating surfaces;

contact walls.

  The features of the present invention and its advantages over the known art will be better

  explained in the following description of an embodiment

  FIG. 1 is a cross-sectional view, along the line I-I of FIG. 2, of a contact group according to FIG.

Wention.

  FIG. 2 is a partial view along arrow F of FIG.

  the contact blade of the contact group of FIG.

  The contact group of FIG. 1, generally referred to as 10, comprises a fixed contact wall 11

255 C 002

  and a movable contact wall 12 between which is interposed an elastic contact blade 13 The walls 11 and 12

  belong to two respective contact elements, fixed and movable, of an electrical device, for example a switch.

  The blade 13 comprises a longitudinal central core 14 from which transversely a series of separate pairs of wing-shaped, folded, divergent appendages 15. Each appendage 15 comprises a first inclined rectilinear segment 16 which deviates from the rib. 14 and is extended by an arcuate connection 17 into a second inclined rectilinear segment 18

in the opposite direction of the previous one.

  The rib 14 has a U shape and is fixed in a corresponding seat 19 of the fixed contact wall 11 with interposition of an insulating support 20, so that the blade 13 does not move away from the wall 11 in the relative opening-closing movement of the contact between the two walls 11 and 12. The seat 19 is connected by two U-shaped faces, 21,

  which follow the corresponding profile pairs of appendices 15, 20 to a surface 22 of contact of the fixed wall 11 itself.

  The movable wall 12 has over its entire extent a single contact surface, designated by 23, parallel to the

surface 22.

  As can be seen in FIG. 1, for each appendix 15, the arcuate connection 17 elastically bears against the surface 23 while the end peduncle 25 of the segment

  18 resiliently bears on the surface 22.

  The segments 16 and 18 have, in the r 81 e of the blade 13,

each their specific function.

  The segment 18 transmits the current between the contact surfaces 22 and 23, while the segment 16 distributes the load

on each point of contact.

  It is verified experimentally that the conformation of the appendages 15, with the described specific function of its parts, ensures a constant and predetermined load on the contact points 4 also taking into account variations in the distance between the two contact surfaces and prevents permanent deformations of the blade, thanks to a work of action and elastic reaction of the two segments 16 and 18. The disadvantages described in the introduction are thus eliminated. To reduce excessive expansions of appendages 15,

  the wall 11 has two steps 24 which delimit lateral -.

  the space occupied by the blade 13 and against which will abut the peduncles 25 in case of strong deformations

of the blade 13.

  The best operating conditions are obtained when s a) the angle ç between the segment 16 and the surface 23 is between 35 and 45; b) the angle f A between the segment 18 and the surface 23 is between 60 and 70; c) the ratio 6 rt between the elastic lever arm has

  segment 16 and the elastic lever arm v of the segment 18 is between 2 and 3.

  It is obvious that the present embodiment, given by way of example, is not limiting with respect to possible

variants and / or additions.

  The shape of the curved appendages of the blade is not narrowly limiting provided that this

  particular cooperation between the two segments of the Appendices.

  The shape of the longitudinal c 8 and the corresponding seat of the fixed contact wall is also not limiting.

  provided that a stable blockage of the blade is achieved therein.

  In the illustrated example, c 8 te 14 and seat 19 are adapted to a cylindrical shape of the elements of the contact group and a sliding movement of the wall 12 on the wall 11 according to the double arrow G. * 35 insulating support 20 is not always necessary:

  in the case of direct contact between the seat 19 and the c 8 te 14 secondary cross passages are created in Mtr-e main passages along the segments 18.

Claims (6)

  1. contact group for electrical apparatus comprising a fixed contact wall (11) on which slides a movable contact wall (12) with interposition of at least one elastic contact blade (13) between two respective parallel contact surfaces said two contact walls, characterized in that said blade (13) comprises a longitudinal central coast (14) from which wing-shaped appendages (15) each consisting of a first 10 and a second successively segment (respectively 16 and 18) connected in an arc, the arc coupling part (17) elastically pressing on one of said two contact surfaces, the end portion (25) of said second segment resiliently pressing on the other of said two contact surfaces said center piece (14) being fixedly secured in a corresponding seat (19)   one of said two contact walls.   2. Contact group according to claim 1, characterized in that said appendages (15) are arranged in pairs in succession longitudinally, separated from each other, each of said pairs consisting of two appendices   (15) diverging from said longitudinal axis (14).   3. Contact group according to claim 1; characterized in that said first (16) and second segments (18) connected   have a rectilinear profile inclined with respect to said contact surfaces (11 and 12) along opposite slopes.   4. Contact group according to claim 1, characterized in that said central coast (14) and said seat (19) corresponding have a U-shaped profile. Contact group according to claim 1, characterized in that between said seat (19) and said center piece (14).   is interposed an insulating support (20).   6. Contact group according to claim 3, characterized in that the angle between said first rectilinear segment and said parallel contact surfaces is between 35 and 45, the angle between said second rectilinear segment and 25500 002   said parallel contact surfaces is between 60 and 70 X, the ratio between the elastic lever arm of said first segment (16) integral with said central core (14)   and the resilient lever arm of said second segment (18) integral with the arc joint (17) is between 2 and 3 -