FR2638903A1 - Electrical contact having fingers - Google Patents

Abstract

The invention relates to an electrical contact having fingers. …<??>Its subject is an electrical contact having fingers, this being obtained by joining several fingers arranged in the form of a bowl (tulip) in contact with the end of a cylindrical component, characterised in that the fingers 2 are simply laid on the said component 1, the contact comprising means 3, 4 for exerting a radial force on each finger. …<??>Application to circuit-breaker (switching) contacts. … …

Description

Electrical finger contact The present invention relates to a contact

electric constituted

by the union of several contact fingers.

The invention finds application in particular in the equipment of circuit breakers. Contacts for circuit breakers are currently made using fingers made of suitably curved metal blades, arranged in a tulip on a cylindrical support and fixed.

to the latter.

Fixing by screwing or riveting leads to

long work weighing on the cost price of the product.

It has been proposed to fix the fingers by crimping a crown; this technique is quick to implement, but it is not very economical, because it requires perfect machining of the parts involved, otherwise there is a risk of electrical contact

to be imperfect.

An object of the present invention is to provide an electrical contact with fingers, the implementation of which to make a contact is a little expensive and leads to a contact mechanically and

electrically excellent.

The present invention has for object an electrical contact with fingers obtained by the union of several fingers arranged in a tulip in contact with the end of a cylindrical part, characterized in that the fingers are simply placed on said part the contact comprising means to exercise on each

finger a radial force.

In a first embodiment, said means comprise, for each finger, a curved leaf spring, said leaf springs

being immobilized by a circular crown.

In another embodiment, said means are constituted by a domed portion of the finger forming a spring, said fingers being immobilized by a ring encircling the fingers at right angles.

of said convex parts.

The invention will be well understood from the following description

of several embodiments of the invention, with reference - 2 - to the accompanying drawing in which: - Figure 1 is an elevational view of a contact finger and the associated spring, - Figure 2 is a top view of the contact finger of Figure 1, - Figure 3 is a partial end view of a contact made with the elements of Figures 1 and 2, - Figure 4 is a top view of a set of springs used in an alternative embodiment of the invention,

- Figure 5 is a side view of the same assembly.

In Figure 1, the reference 1 designates a contact support consisting of a tubular metal part 1 having a cylindrical surface portion 1A on which are placed side by side

contact fingers 2, 2 ', 2 "with a distance e between them (figure 3).

Each finger 2 consists of a metal blade, of generally elongated rectangular shape, terminated at one end by a curved portion 2A, the convexity of which is turned towards the axis of the contact, and intended to cooperate with a non-male contact. represented. The sliding of the finger 2 relative to the support 1 is limited by virtue of a heel 2C of the finger which engages in a housing 1C

of the support, of axial dimension a little greater than that of the heel.

The contact fingers are held in a tight position against the support by means of springs such as the spring 3 consisting of a rectangular metal blade bent and curved so as to present a convex part 3A framed by two parts 3B and 3C resting on finger 2. The spring pressure is provided by a crown 4 of diameter chosen so that the springs are

crushed when the crown is forcibly engaged around the springs.

The dashed line 3 'shows the state of the spring before the

crown square.

Each spring 3 thus crushed exerts on the finger 2 a force sufficient to hold it on the support 1. The crown 4 comprises a conical inner surface portion 4A intended to facilitate

its introduction.

The spring is limited in its axial and lateral movements -3-

thanks to two U-shaped 2D stops, 2E, made in the finger.

The branches of the U constitute lateral stops, the bar of the U

axial stops.

It will be noted that the contact finger can be made very simply by stamping a perfectly rectangular part. Thanks to a perfect seat of the finger on its support, there is no risk of introduction of dust or pollution products between the finger and the support causing an increase

the value of the ohmic resistance of the contact.

The implementation is simple and therefore inexpensive.

In the variant shown in Figures 4 and 5, the springs 20 which have the same shape as the spring 2 of Figure 1, are made from the same metal sheet stamped so as to leave, between each spring, an isthmus 21 curved to take into account the increase in diameter due to the deployment of this spring assembly at the time of positioning around the fingers. FIG. 6 is an alternative embodiment in which the

spring is formed in a curve given to the finger itself.

The figure shows a cylindrical finger support 10 and a finger 25, comprising a curved part 25A. It is this part, compressed by a crown 30, which ensures the function of the spring by its elasticity and allows the contact finger to be held in place. As previously a lug 25C cooperating with a recess 10C

of the support, limits the axial movements of the finger.

This embodiment is particularly economical.

The fingers having the elasticity of a spring thus make it possible to produce a system allowing large tolerances on the diameters.

contact supports and finger thicknesses.

-4-

Claims (6)

1 / Electrical contact with fingers obtained by the union of several fingers arranged in a tulip in contact with the end of a cylindrical part, characterized in that the fingers (2) are simply placed on said part (1) the contact comprising means (3, 4) to exert a radial force on each finger. 2 / electrical contact according to claim 1, characterized in that said means comprise, for each finger (2), a blade- domed spring (3), said leaf springs being immobilized by a circular crown (4). 3 / electrical contact according to claim 1, characterized in that the leaf springs are obtained from the same part and joined by a metallic isthmus (21). 4 / electrical contact according to one of claims 2 and 3, characterized in that the axial displacements of the finger (2) relative to the support are limited by a lug (2C) of the finger cooperating with a recess (1C) of the support. / Electrical contact according to one of claims 2 to 4, characterized in that the axial and lateral displacements of the spring (3) relative to the finger (2) are limited by U-shaped stops (2D, 2E) worn by the finger. 6 / electrical contact according to one of claims 2 to 5, characterized in that said ring 4 comprises an inner surface portion conical (4A). 7 / An electrical contact according to claim 1, characterized in that said means are constituted by a portion (25A) bulging of the finger (25) forming a spring, said fingers being immobilized by a ring (30) encircling the fingers to the right of said bulging parts . 8 / electrical contact according to claim 7, characterized in that the axial movements of the fingers are limited by a lug (25C) posted by the finger cooperating with a recess (1OC) of the support (10).