GB2124031A

GB2124031A - Electric contact device

Info

Publication number: GB2124031A
Application number: GB08317945A
Authority: GB
Inventors: Serge Marcel Regnault
Original assignee: Jaeger
Current assignee: Jaeger
Priority date: 1982-07-06
Filing date: 1983-07-01
Publication date: 1984-02-08
Also published as: ES282105U; ES282105Y; DE3324410A1; IT1170430B; GB8317945D0; IT8348614A0; FR2530068A1

Abstract

A contact-maker comprises a plurality of superimposed sheet-like elements (20, 40, 60) or blades each formed with a deformable curved portion (21, 41, 61) arranged to close against a contact upon its deformation. Successive deformations of these portions are obtained by the same actuating member (70), each portion being deformed after the portion immediately preceding it (on the path of travel of the member 70) and all portions being deformed at the end of travel of the member (70). <IMAGE>

Description

SPECIFICATION Electric contact device The present invention relates to an electric contact-maker or contact device which comprises a sheet-like element formed with a deformable curved portion which is provided on its concave face with a conductive region arranged to close against a contact upon deformation of the curved portion.

This curved portion is generally arranged to deform with sudden or "snap" action in such a manner as to produce a sudden and clean contact-making on the occurence of snapping, further enabling a tactile sensation for the user who presses on the deformable portion either directly or by means of a button.

The devices existing hitherto, however, each enable only a single contact to be made and operate in the "all or nothing" manner, that is to say open-contact or closed-contact, corresponding to the button being released or pushed right in.

In accordance with the present invention, there is provided an electric contact device, comprising a plurality of superimposed sheetlike elements each formed with deformable curved portion which is provided on is concave face with a conductive region arranged to close against a contact upon deformation of the curved portion, the curved portions of the blades lying on a common axis, the device further comprising an actuating member displaceable along said axis to cause deformation of the curved portions of the successive elements, each element being so deformed-after the element which immediately precedes it and all said elements being deformed at the end of travel of said actuating member.

This device enables a plurality of successive contacts to be made, for example by means of a single push-button, according to the extent to which this push-button is pushed in, while retaining if required the advantages of snap action (clean contact and tactile sensation).

The device can likewise be arranged as an "overtravel" switch, operating like a conventional contact-maker but with the possibility of closing an additional contact in the event of pushing in the push-button further, possibly with a greater effort.

Other features and advantages of the present invention will be apparent from the following description of embodiments of the invention given by way of examples only and with reference to the accompanying drawings, in which: Figures 1 to 4 show the different phases of actuation of a contact device forming a first embodiment of the invention; and Figures 5 and 6 are two simplified embodiments.

Fig. 1 shows a contact-maker formed from a stack of different sheet-like elements or blades: thus from top to bottom (as viewed in the Figure), there are found: a first element 10 to protect and hold the lower elements; an element 20 having a first deformable curved portion 21; a rigid element 30 forming a spacer; an element 40 having a second deformable curved portion 41; a rigid element 50; an element 60 having a third deformable portion 61.

The first curved portion 21 is turned with its convex face upwards. The second curved portion 41 is turned likewise, parallel to the first for example, while the third curved portion 61 is turned with its convex face downwards; nevertheless, the three curved portions are aligned on one and the same axis generally normal to the planes of the sheet-like elements in which they are formed. For actuating the contact-maker, there is provided a push-button 70 displaceable along said axis to bear at the centre of the first curved portion 21 which is left visible or accessible through an aperture formed in the first element 10: further a reaction member is provided by an extra thickness or projection 81 formed on a support element 80.The cross-section S1 of the push-button 70 and the cross-section S2 of the projection 81 are substantially equal for portions 21 and 61 of identical or like dimensions, and the cross-sections S1 and S2 are less than the cross-sections of the deformable portions 21 and 61 to which they are adjacent.

Fig. 1 shows the structure of the switch at rest; if the push-button 70 is now pressed downwards, the first deformable portion 21 will be deformed as indicated in Fig. 2: the lower or concave face of portion 21 comes into contact with the upper or convex face of the portion 41 which remains only slightly or not at all deformed at this stage. A first electrical contact can thus be made if electrical conductors are provided on the faces which come into contact, for example in the form of conductive regions or patterns printed by a silk-screen process on the elements 20 and 40.

An additional pushing-in of the push-button 70 (Fig. 3) will continue to deform the portion 21 downwards until the lower face of the second deformable portion 41 comes into contact with the upper face of the rigid element 50. Conducting regions or patterns provided on these two faces which come into contact thus to enable a second electrical contact to me made.

The thickness h, of the spacing element 30 is selected to approximate to the amplitude of deformation of a curved portion which enables the portion 41 to be deformed without excessive pressing in of the button and therefore without excessive deformation of the first portion 21.

If the push-button 70 continues to be pushed in (Fig. 4), this will come to bear, by means of the portions 21 and 41, on the rigid element 50 which will cause a general pushing in of the assembly of elements 10 to 60.

The lower deformable portion 61, which is turned with its convex face towards the fixed base support 80 and the projection 81, will be applied by this against the lower face of the rigid element 50: it is thus possible to make a third contact between this lower face and the upper face of the portion 61.

The thickness h2 of the projection 81 is selected at a value at least equal to the amplitude of deformation of the portion 61.

Fig. 5 illustrates a simplified embodiment comprising only the upper two curved portions of Fig. 1: the stack of elements 10 to 40 and the push-button 70 are again found, but the stack rests on a rigid element 50' which is fixed from now on, as distinct from the element 50 of Fig. 1.

Fig. 6 illustrates another embodiment with two contacts where, in comparison with Fig.

1, the elements 20 carrying the first deformable portion 21 and the spacer element 30 have been eliminated.

The deformable curved portions may be obtained, for example, from sheets of Mylar (R.T.M) or like plastics material on which blisters have been formed and provided with conductive patterns by a silk-screen printing process. The various deformable portions may have identical characteristics (amplitude of deformation and force necessary to cause the snap-action), but it is likewise possible for the portions to have different mechanical properties if it is desired to obtain variable tactile sensations: this may be so, for example, in the case of limit switches where the limit contact (for example that made by the deformation of the final portion 61) corresponds to an increased pressure exerted on the pushbutton to prevent any untimely closing of the contact.

Claims

1. An electric contact device, comprising a plurality of superimposed sheet-like elements each formed with deformable curved portion which is provided on its concave face with a conductive region arranged to close against a contact upon deformation of the curved portion, the curved portions of the blades lying on a common axis, the device further comprising an actuating member displaceable along said axis to cause deformation of the curved portions of the successive elements, each element being so deformed after the element which immediately precedes it and all said elements being deformed at the end of travel of said actuating member.

2. A device as claimed in claim 1, in which each said deformable curved portion is arranged to deform with snap-action such that the succession of deformations of the curved portions transmits a succession of tactile sensations to the actuating member.

3. A device as claimed in claim 1 or 2, in which two adjacent deformable curved portions have their concave faces turned in the same direction, the conductive region of the first-deformed portion closing a contact with a conductive region provided on the opposite face of the other portion.

4. A device as claimed in claim 3, in which the two deformable elements are separated by a spacer element having a thickness approximating to the amplitude of the deformation of the first-deformed portion.

5. A device as claimed in any one of claims 1 to 4, in which said conductive region on the concave face of a said deformable portion is arranged upon deformation, to close against a contact with a carrier by the opposite face of an adjacent rigid element.

6. A device as claimed in claim 5, in which the rigid element is displaceable under pressure along said axis from the actuating member, and separates the deformable portions of two said elements each turned with its concave face towards the rigid element.

7. A device as claimed in Claim 6, further comprising a fixed reaction member causing the deformation of the deformable curved portion of the element disposed between this member and the movable rigid element, in response to pressure exerted on the latter curved portion.

8. A device as claimed in claim 7, in which the reaction member comprises a projection of cross-section less than that of the adjacent deformable curved portion and a height at least equal to the amplitude of deformation of this portion.

9. An electric contact device substantially as herein described with reference to Figs. 1 to 4 or 5 and 6 of the accompanying drawings.