GB2091042A

GB2091042A - Electric switch with positive opening device

Info

Publication number: GB2091042A
Application number: GB8138787A
Authority: GB
Original assignee: Carpano and Pons SA
Current assignee: Carpano and Pons SA
Priority date: 1980-12-30
Filing date: 1981-12-23
Publication date: 1982-07-21
Also published as: SE8107603L; IT8125886A0; DE3147122A1; FR2497396A1; GB2091042B; ES8302952A1; SE442929B; IT1140407B; DE3147122C2; IT8123920V0; ES508407A0; FR2497396B1

Abstract

A switch comprises a conducting contact bar (4), mounted to rock about a fixed conductor (11). When a first contact pair (15-16) is closed, a second contact pair (19-20) is open and vice versa. When the first contact pair (15-16) stick together accidentally, after downward movement of a first projection (41) of a control lever (24 ) in order to allow opening of the pair (15-16), a second projection (42) of the same lever (24) releases the bar (4) positively by pressing at a point (46). When a control projection (26) reaches an upper level (33) of a cam (27), at the time of closure of the second contact pair (19-20), the profile of the bar (4) is such that there is no danger of the second projection (42) coming into accidental contact with the bar (4). The switch may be used in a programmer for an electric domestic appliance. <IMAGE>

Description

SPECIFICATION A switch for use in programmers for electric domestic appliances The pressnt invention relates to switches used in particular in programmers for electric domestic appliances. They comprise a conducting rocker switch positioned longitudinally, whereof the central part cooperates constantly with a fixed central contact point serving as a rocking point for the latter and whereof the first and second end parts are able to cooperate respectively, by first and second moving contact points, with first and second fixed contact points. A compression spring is located between the second end part of the rocker switch and a support provided on part of a control lever, arranged opposite this second end part.This control lever is mounted to pivot substantially parallel to the rocker switch and is arranged in such a manner that in a first inoperative position of the switch, a first projection of the control lever presses against the rocker switch in order to keep the first contact closed and simultaneously to keep the second contact open.

This control lever is able to be actuated by a moving control member, in orderto make the switch occupy a second position in which the second contact is closed and the first contact is simultaneousiy opened. A second projection, supported by the control lever, is provided in order to press against the rocker switch in order to open the first contact positively when the rocker switch remains inopportunely stuck to the first fixed contact point, after the first projection of the control lever has been moved away from the rocker switch in order to facilitate opening of the first contact under the action of the spring.

In known switches of this type, such as that described in French patent no. 2 101 394, the second projection supported by the control lever is integral with a second lever mounted to pivot on the control lever and it was necessary to provide an arm on this lever, which arm, immediately after the second projection has released the rocker switch, cooperates with a fixed stop, in order to cause the arrangement of the second lever to pivot and to prevent the second projection from coming into inopportune contact with the rocker switch, at the time of closure of the second contact. An arrangement of this type is relatively complicated. It is a drawback particularly when the rocker switch and the control lever have relatively small dimensions and have to be housed in an insulating casing of reduced width.

The switch which is the object of the invention is characterised in that the second projection supported by the control lever is cast in one piece with the latter and in that the respective trajectories of the second projection and of the part of the rocker switch with which it cooperates, as well as the profile of said rocker switch are such that the second projection does not come into accidental contact with the rocker switch, at the time of closure of the second contact.

The present invention makes it possible to produce a switch which is able to provide positive opening of its contacts which have stuck accidentally, this switch being ofsimplerconstruction than the prior art and thus being able to occupy a relatively smaller space and also being able to be fitted more easily in the insulating casing which is intended to accommodate it. In fact, according to certain particularly advantagecus embodiments, before they are fitted in an insulating casing, the rocker switch, control lever and compression spring constitute a subassembly which is able to be assembled in advance and to remain assembled in order to be able to be moved, possibly automatically, for the purpose of easy insertion in said casing.This insertion may take place in a direction at right angles to the pivot axis of the control lever, subsequent positioning of this single axis being possible easily, by axial displacement of the latter.

The accompanying drawings illustrate, by way of example, embodiments of the switch, according to the present invention.

Figures 1 to 4 show a first embodiment of the invention, in different operating stages, in elevation/section.

Figure 5 shows the same first embodiment in section on line V-V of figure 3.

Figures 6 and 7 show a second embodiment of the invention, in operating stages corresponding to those illustrated in figures 2 and 3 and in elevation/section.

Figures 8 and 9 show a third embodiment of the invention, in operating stages corresponding to those illustrated in figures 2 and 3 and in elevation/section.

As illustrated in figures 1 to 5, the switch according to the invention is housed in an insulating casing 1 constituted in particular by parallel walls 2 and 3 (figure 5). Located between these walls is a conducting rocker switch 4 positioned longitudinally in the direction of arrows 5 and 6 (figure 1) by two lugs 7 provided in its central part and each housed in a groove 8, of corresponding dimensions, provided in the walls 2 and 3 of the casing 1 (figure 5). The central part 9 of the rocker switch 4 is enlarged in order to constitute a support point which cooperates constantly with a fixed central contact point 11 serving as the rocking point.This fixed central contact point 11 forms part of a contact-support strip 12 extending from the casing. Afirst end part 14 ofthe rocker switch 4 is able to cooperate by means of a first enlarged part 15 with a first fixed contact point 16 forming part of a second contact-support strip 17.

The second end part 18 remote from the first end part 14 of the rocker switch 4 is able to cooperate by means of a second enlarged part 19 with a third fixed contact point 20 forming part of a third contactsupport strip 21.

A control lever 24, advantageously made from insulating material, is mounted to pivot substantially parallel to the rocker switch 4, about a shaft 25 arranged transversely with respect to the walls 2 and 3 of the casing 1. It comprises a control projection 26 provided for cooperating with a movable control member constituted in this example by a rotary cam 27. This cam 27 comprises for example a lower level 31, a central level 32 and an upper level 33.A compression spring 34 is located between the second end part 1 of the rocker switch 4 and a support 28 provided on a pert 28' of the control lever 24, located opposite the second end part 18. The support point 30 for one end of the spring 34 on the rocker switch 4 is closerto the rocking point 11 of the latter than the support point 28 of the other end of the spring 34 with respect to the pivoting point 25 of the control lever 24.

The control lever 24 comprises a first projection 41 able to cooperate for example with the first end part 14 of the rocker switch 4 in orderto keep the contact 15-16 closed and the second contact 19-20 open at the same time. It comprises a second projection 42 integral with a part 43 of the control lever 24 remote from the part 28 against which the compression spring 34 bears, with raspect to the pivot point 25 of said lever. This second projection 42 is located on an extension 44 of the control lever 24, extending on the opposite side of the rocker switch 4 to said control lever, between the first moving contact point 15 and the central fixed contact point 11.This second projection 42 is provided for releasing from the fixed contact point 16, the enlarged part 15 of the rocker switch 4, when this enlarged part 15 remains stuck accidentally.

In the inoperative position of the switch, illustrated in figure 1, the respective positions of the support points 30 and 28 of the spring 34 on the rocker switch 4 and on the control lever 24 are such that the first projection 41 of the control lever 24 bears against the first end part 14 of the rocker switch 4 in order to keep the contact 15-16 closed. In this inoperative position, the control projection 26 is located opposite the lower level 31 of the cam 26, withoutouch- ing the latter.

As soon as the cam 27 rotates in the direction of arrow 50, it lifts the control projection 26 slightly towards its central level 32 (figure 2), the first projection 41 tending to move away from the first end part 14, the spring 34 being slightly compressed at the same time.

If the first enlarged part 15 remains stuck accidentally to the first fixed contact point 16 (figure 2), the first projection 41 moves away effectively from the first end part 14 and the second projection 42 comes to bear against the part 46 of the rocker switch 4 and opens the contact 15-16 positively by releasing the first enlarged part 15 of the rocker switch 4. Instantaneously, the first end part 14 comes to bear against the first projection 41 underthe action of the spring 34.

If the first enlarged part 15 does not remain stuck to the first fixed contact point 16, the first end part 14 remains constantly in abutment against the first projection 41 and the second projection 42 does not come into contact with the part 46 of the rocker switch 4.

In all cases, when the control projection 26 reaches the central level 32 of the cam 27 (figure 3), the first end part 14 bears against the first projection 41. The first contact 15-16 is open. The same is true for the second contact constituted by the second enlarged part 19 and by the second fixed contact point 20.

When in a latter stage, the control projection 26 reaches the upper level 33 of the cam 26 (figure 4), tie second enlarged part 19 has come into contact with the second fixed contact point 20, the first pro jection 41 being separated sligh4!y-,rorr. the first end part 14 and the second contact 19-23 being closed whilst the first contact 15-16 is open. DI irking the rotation in the direction of arrow 52 (figure Si of the rocker switch 4 and of the control lever 24, the respective trajectories of the second projection z2 and of the part 46 of the rocker switch with which it has cooperated, as well as the profile, seen laterally (figures 1 to 4) of said rocker switch 4 are such that the second projection 42 does not come accidentally into contact with the rocker switch 4, at the time of closure of the second contact 19-20.

When, after a further rotation of the cam 27 in the direction of arrow 50, the control projection 26 drops abruptly to another central level 32, not shown in the drawing, the various component parts once more occupy the position illustrated in figure 3, the second projection 42 limiting an accidental rotation in the direction of arrow 51 (figure 3) of the rocker switch 4, which rotation is due to the inertia of said rocker switch. The first contact 15-16 is thus prevented from closing accidentally for a brief instant.

It should be noted that before fitting the switch in the casing 1, the rocker switch 4, control lever 24 and the spring 34 constitute a sub-assembly which can be assembled in advance, the spring 34 keeping the rocker switch 4 in abutment against both the first and second projections 41 and 42 of the control lever 24.

In the second embodiment of the invention, illustrated in figures 6 and 7, the second projection 42 of the first embodiment is replaced by a second projection 42a, arranged almost like this second projection 42. The only difference as regards position of this second projection 42a resides in the fact that it is located beyond the first moving contact point 15, opposite the first end part 14 of the rocker switch 4.

The end 14a of the first end part 14 of the rocker switch 4 is positioned such that the second projection 42a does not come into contact with the first end part 14 at the time of closure of the second contact 19-20.

All the other constituent parts are identical to those of the first embodiment (figures 1 to 5).

The operation of this second embodiment is similar to that of the first If the first contact 15-16 remains stuck (figure 6), the second projection 42a comes into contact with the end 14a of the rocker switch 4 and positively releases said rocker switch by opening the first contact 15-16 (figure 7). When the control projection 26 reaches the upper level 33 of the cam 27, the second projection 42a is able to pivot freely beyond the first end 14a, without coming into contact with the latter.

The end of the control lever 24, serving as a support for the spring 34 advantageously comprises a third projection 55 located on the opposite side of the rocker switch 4 from the control lever 24. This third projection 55 serves solely to keep the subassembly consisting of the rocker switch 4-control lever 24 spring 34 assembled, before it is fitted in the casing 1. When this sub-assembly is fitted in the casing 1, a clearance always exists between this third projoction 55 and the roc%sr switch 4.

ln the 4inirt!1 embodlmen; illusirated in figures 8 and i, the second protection 42 owl the first embodiment b replaced by a second pro;'ection 42b integral with the part 28' oithe control leper 24, against which bears the compression spring 34 and it is located beyond the support point 28 for the spring 34, in the direction of the second end part 18 of the rocker switch 4, on the same side of the latter as the control lever 24. This second projection 42b is substantially opposite the control projection 26.The profile of the rocker switch 4 comprises a recess 45b arranged in the direction of the support point 30 for the spring 34. All the other constituent parts are identical to those ofthefirst embodiment.

The operation of this third embodiment is similar to that of the first. if the first contact 15-16 remains stuck (figure 2), the second projection 42b comes into contact with a part 46b of the rocker switch 4 and releases said rocker switch 4 positively thus opening the first contact 15-16 (figure 9). When the control projection 26 reaches the upper level 33 of the cam 27, at the time of closure of the second contact 19-20, the second projection 42b wiil be able to pivot freely in the direction of arrow 52 (figure 9) by penetrating the recess45b without coming into contact with the rocker switch 4.

Without diverging from the scope of the present invention, the part 43 of the rocker switch, which supports the first projection 41 and the second projection 42 in the first embodiment, could be dispensed with according to the broken line shown in figures 8 and 9. The first projection 41 would thus be replaced by a first projection 41 b, shown in broken line, located on the same part 28' of the control lever 24 as the second projection 42b, but on the opposite side of the rocker switch 4 to said control lever 24. in the position of figure 9, the first projection 41 b would bear against the rocker switch 4.

The present Invention may advantageously be used in particular in programmers for electric domestic appliances.

Claims

1. A switch comprising, on the one hand a conducting rocker switch positioned longitudinally, whereof the central part cooperates constantly with a fixed central contact point serving as a rocking point for the latter, whereof the first and second end parts are able to cooperate respectively, by first and second moving contact points with first and second fixed contact points a compression spring being located between the second end part of the rocker switch and a support provided on a part of a control lever, located opposite this second end part, the lever being mounted to pivot substantially parallel to the rockerswitch and arranged in a manner such that in a first inoperative position of the switch, a first projection of the control lever bears against the rocker switch in order to keep the first contact closed and to keep the second contact open at the same time, the control lever being able to be actuated by a movable control member, in orderto make the switch occupy a second position in which the second contact is closed and the first contact is opened simultaneously, a second projection suw sorted by the control lever being provided in order to come to bear against the rocker switch in crderto open the first contact positively in the case when the rocker switch remains stuck accidentally to the first fixed contact point afterthe first projection of the control lever has been moved away from the rocker switch in order to allow opening of the first contact under the action of the spring, charactensed in that the second projection, supported by the control lever is cast in one piece with the latter and in that the respective trajectories of the second projection and of the part of the rocker switch with which it cooperates, as well as the profile cf said rocker switch are such that the second projection does not come into accidental contact with the rocker switch, at the time of closure of the second contact.

2. A switch according to claim 1, characterised in that the second projection provided for releasing the rocker switch from the first fixed contact point, is integral with a part of the control lever remote from the part against which the compression spring bears, with respect to the pivot point of said lever and is located on the opposite side of the rocker switch to the control lever, between the first moving contact point and the fixed central contact point.

3. A switch according to claim 1, haractensed in that the second prosefflion provided for releasing the rocker switch from fie first fixed contact point, is integral with a part of the control lever remote from the part againstwhich the compression spring bears, with respect to the pivot point of said lever and is :crated on the opposite side of the rocker switch to the control lever, beyond the first moving contact point, the end of the first end part of the rocker switch being positioned in a manner such that the second projection does not come into contact with the first end part, at the time of closure of the second contact.

4. A switch according to claim 1, characterised in that the second projection provided for releasing the rocker switch from the first fixed contact point is integral with the part of the control lever and is located beyond the support point for the spring, in the direction of the second end part of the rocker switch, on the same side of the latter as the control lever, the profile dthe rocker switch comprising a recess provided in the direction of the support point for the spring, in a manner such that the second projection may be housed in said recess, at the time of closure of the second contact

5. A switch substantially as hereinbefore described with reference to the accompanying draw ings