EP1930927A1

EP1930927A1 - Electric switch with a pivoting switching member

Info

Publication number: EP1930927A1
Application number: EP06425824A
Authority: EP
Inventors: Ennio Calderara
Original assignee: BTicino SpA
Current assignee: BTicino SpA
Priority date: 2006-12-07
Filing date: 2006-12-07
Publication date: 2008-06-11

Abstract

Electrical switch (1) comprising:
- at least two connection terminals (11.1, 11.2),
- a fixed electric contact (13.2) that is electrically connected to one (11.2) of the two connection terminals (11.1, 11.2),
- a pivoting and electrically conductive switching member (16), comprising at least one mobile electric contact (18.2),
- an operating mechanism (20) for this switching member (16), which is suitable for oscillating this switching member between two preset positions, in one of which the mobile electric contact (18.2) is abutted against the fixed electric contact (13.2),
- a supporting element (14, 15) for said switching member (16), the supporting element (14, 15) being electrically conductive and electrically connected to the other of the two connecting terminals (11.1).

The switch (1) further includes an elastically deformable conductive element (30) interposed between the supporting element (14, 15) and said switching member (16) for ensuring the electrical continuity between said supporting element (14, 15) and said switching member (16) .

Description

The present invention relates to electric switches, and more particularly, switches of a type in which the switching is carried out due to a pivoting switching member which moves between two stable positions.
By "switch" is meant herein both a device that opens and closes a single contact and a device that opens one contact and simultaneously closes another contact, and vice versa (diverter switch).
Several types of switches of the above kind belong to the prior art, generally including: at least two connection terminals, at least one fixed electric contact being electrically connected to one of the two connection terminals and a switching member, which is provided at one end thereof with at least one mobile electric contact and resting on a fulcrum or support that is electrically connected to the other of the two connection terminals. These switches further include an operating mechanism to be manoeuvred by means of an axial push-button, or lever, or rocker key for moving the switching member such that the latter rotates to reach either one of its two stable positions.
A switch as discussed above and push-button operated is described for example in the International Patent Application WO 2006/106554 .
By means of tests that have been carried out using a high-speed video camera, it has been possible to observe how, in the above prior art switches, the pivoting switching member, during the switching process, can be lifted from the fulcrum on which it is rested despite being held thereto by suitable resilient means.
This disconnection, even though limited to a few split seconds, can impair the good operation of the switch. In fact, during this disconnections, electric micro-arcs are formed that cause local corrosions or fusions which can, in turn, cause overheating or power failure.
The object of the present invention is to provide an electric switch which free of the drawbacks cited above with reference to prior art switches, or which is affected by these drawbacks in a very reduced manner as compared with prior art switches.
This object is achieved by means of a switch as generally defined in claim 1. Preferred and advantageous embodiments of a switch in accordance with the present invention are defined in the annexed dependent claims.
The invention will be better understood from the following detailed description of particular embodiments, which is given by way of example and is not to be considered limitative in any way, with reference to the annexed drawings, in which:

Fig. 1 shows a side sectional view, with parts partially disassembled, of a preferred embodiment of a switch according to the invention;
Fig. 2 shows a top view of the contact-holder structure of the switch in Fig. 1;
Fig. 3 shows an enlarged detail of the switch in Fig. 1; and
Fig. 4 shows a partial view of an alternative embodiment of a switch in accordance with the present invention.

In the figures, equal or similar elements will be designated with the same numerals.
With reference to Fig. 1 and 2, a particularly preferred embodiment of an electric switch 1 in accordance with the present invention will be described herein below.
As stated above, by "switch" is meant herein both a device that opens and closes a single contact and a device that opens one contact and simultaneously closes another contact, and vice versa (diverter switch).
The electric switch 1, which is depicted in Fig. 1 with partially detached parts, and in the particular example is a push-button switch, comprises a supporting structure 2 made of insulating material, such as plastics, preferably and in a non-limiting manner approximatively having the shape of a parallelepiped with two pairs of side walls, smaller 3,4 and greater 5,6, respectively.
The side walls 3,4,5,6 are closed and joined to a bottom portion 7 of the supporting structure 2. Between the side walls and the bottom portion 7, the supporting structure 2 defines an inner chamber 8 facing, by means of an opening 9, outward of the supporting structure 2.
In the particular example as illustrated in the figures, the bottom portion 7 has shaped walls defining a contact-holder structure 10 made of insulating material. The contact-holder structure 10 preferably accommodates three connection terminals 11.1, 11.2, 11.3 (the latter can be seen only in Fig. 2), such as screw clamps, each being accessible via two openings, the one for having access to the screw of the clamp and the other to insert an electric lead in the clamp. Two of the three connection terminals 11.1, 11.2, are connected, as one piece in this example, to respective sheet-metal tags 12.1, 12.2 (seen in Fig. 2) being in the contact-holder structure 10. Each of these tags is provided with a fixed electric contact 13.1, 13.2, respectively, at one end thereof.
The third connection terminal 11.3 is connected, as one piece in this example, to L-shaped sheet-metal bar 14, which is arranged in the contact-holder structure 10 such that an edge 15 thereof protrudes in the direction of the opening 9 in a substantially central position relative to the fixed electric contacts 13.1, 13.2.
The switch 1 further includes an oscillating switching member 16 suitable to establish electric connections, which in this particular example of Fig. 1 is embodied by a pivoting jumper 16 made of metal. The switching member will be hereinafter referred to as the "pivoting jumper" without however introducing any limitation thereto.
In the example, the pivoting jumper 16 is reverse saddle-shaped, having a rounded central profile and is connected within the inner chamber 8 of the supporting structure 2 in a pivoting manner about an axis perpendicular to the sheet plane. The pivoting jumper 16 has a central seating part 17 in contact with the edge 15 of the tongue 14 and two arms having mobile electric contacts 18.1, 18.2 at the ends thereof.
The pivoting jumper 16 is such that it can be moved to rotate about its central seating part 17 in order to establish electric connections. It should be observed that the tongue 14, and particularly the edge 15 thereof, are a supporting element for the pivoting jumper 16.
The electric switch 1 further includes a control mechanism 20 to be associated with the supporting structure 2 at the opening 9 thereof and suitable to move the pivoting jumper 16. In the particularly preferred, though non-limiting embodiment, being illustrated in Fig. 1 and that will be briefly described below, the control mechanism 20 is provided according to the teachings of the International Patent Application WO 2006/106554 .
Particularly, the control mechanism 20 includes a push-button 21 and means for mechanically coupling the push-button 21 to the supporting structure 2 such that the push-button 21 can be fastened to the supporting structure 2 while being movable relative thereto in a sliding direction substantially parallel to the axis of opening 9. Preferably, these mechanical coupling means include a holding and guide frame 22 for the push-button 21. In the example, the push-button 21 includes an upper portion embodied by a key 23, a cover-platelet 23a being associated therewith.
Two helical compression springs 26 allow the push-button 21 to be held in the distal position, or rest position thereof, relative to the supporting structure 2.
As shown in Fig. 1, the control mechanism 20 includes a control element 27 comprising a block 28 of insulating material and a spring-controlled pin 29, preferably made of metallic material. In the example, the block 28 is mounted to the holding and guide frame 22 in a pivoting manner about an axis perpendicular to the sheet plane.
The spring-controlled pin 29 has a rounded tip and is biased by a spring (not seen in the figures) that is compressed in a cavity of the block 28 in order to provide an elastic connection between the block 28 and the underlying pivoting jumper 16, when the control mechanism 20 is fixed to the supporting structure 2. The block 28 is shaped on top such as to have a cavity 32 with substantially step-shaped surfaces.
The control mechanism 20 further comprises a pressure transmission means 33, illustrated in phantom in Fig. 1, which has two substantially pointed ends 34a, 34b. This pressure transmission means 33 is attached to the push-button 21 below the key 23 in a pivoting manner about a third axis substantially perpendicular to the sheet plane.
Two foil springs 36a and 36b, being as one piece in the example, are arranged between the key 23 and the pressure transmission means 33 such that the latter is hold in a rest position, in which the ends 34a and 34b thereof are substantially equidistant from the key 23.
The operation of the control mechanism 20, particularly with reference to the interaction of the latter with the pivoting jumper 16 is described in the above-mentioned International Patent Application WO 2006/106554 , and will not be further discussed herein.
According to the present invention, the electric switch 1 further comprises an elastically deformable conductive element 30 that is interposed between the supporting element 14 and the pivoting jumper 16 to ensure the electric continuity between the supporting element 14 and the pivoting jumper 16. Conveniently, this elastically deformable conductive element is a laminar elastic element 30, preferably made of phosphor bronze.
With reference to Fig. 2, in a particularly advantageous embodiment, the laminar elastic element 30 has a curved profile, essentially U-shaped or V-shaped and has a middle area 34 that is preferably rounded, which rests on the supporting element 14, 15 and two side tongues 32, 33, preferably curved, which are arranged on opposite sides relative to said middle area 34 and suitable to interfere with the pivoting jumper 16.
In a particularly advantageous embodiment, the supporting element 14 includes a forward region 15 which acts as a rest point and fulcrum for the switching member 16, and includes a backward region 31 that acts as the rest point for the laminar elastic element 30.
It should be observed that, in the particular example as illustrated in the figures, the supporting element 15 is a metallic bar having the forward region 15 thereof substantially cusp-shaped and having the backward region 31 that is a recess or notch of the bar 14. It should be further observed that, by providing the width of the middle portion 17 of the pivoting jumper 16 to be of a greater size than the width of the recess 31, the pivoting jumper 16 is thus rested on two parts 15 of the bar 14, which are counter-posed relative to the recess 31. Furthermore, by providing the width of the middle portion 34 of the laminar elastic element 30 to be lower than the width of the recess 31, the middle portion 34 of the laminar elastic element 30 is received within the recess 31.
In a particularly preferred embodiment, the middle region 34 of the laminar elastic element 30 has a lower width than the width of the two side tongues 32, 33 arranged on opposite sides relative to said middle area 34 and suitable to interfere with the pivoting jumper 16. Thereby, the laminar elastic element 30 is sandwiched between the supporting element 14 and the pivoting element 16.
It should be observed that, in practice, the side tongues 32 and 33 of the laminar elastic element 30 are such as to interfere with a surface of the pivoting element 16 opposite the surface of the latter on which the spring-loaded pin 29 (seen in Fig. 1) is intended to slide upon operation.
Fig. 4 shows a possible variant embodiment of the switch 1 in Fig. 1. Only a partial view of this variant embodiment has been illustrated in Fig. 4, which corresponds the switch portion including the pivoting switching member 16, the elastically deformable conductive element 30 and a fixed electric contact 13.2. As may be appreciated in Fig. 4, the teachings of the present invention can be also applied to a switch comprising a pivoting switching member 16 with an individual mobile contact 18.2. In the variant embodiment in Fig. 4, the elastically-deformable conductive element 30 has roundings at opposite two of the end portions 32, 33 thereof. This contrivance, which can be however applied to the embodiment in Fig. 1, advantageously facilitates the sliding of these end portions 32, 33 on the surface of the switching member 16 intended to interfere with these end portions.
From the description given above, it is understood how a switch in accordance with the invention fully achieves the pursued object, in that the provision of an elastically deformable conductive element interposed between the switching member and the supporting element for the latter allows maintaining the electrical continuity between the supporting element and switching member even when, because of bounces, the switching member is lifted and gets detached from the supporting element.
Obviously, to the switch described above, those skilled in the art, aiming at satisfying contingent and specific requirements, may carry out a number of modifications and variations, all being however contemplated within the scope of protection of the invention, such as defined in the annexed claims.

Claims

An electric switch (1) comprising:
- at least two connection terminals (11.1, 11.2),

- a fixed electric contact (13.2) that is electrically connected to one (11.2) of the two connection terminals (11.1, 11.2),

- a pivoting and electrically conductive switching member (16), comprising at least one mobile electric contact (18.2),

- an operating mechanism (20) for this switching member (16), which is suitable for oscillating said switching member between two preset positions, in one of which the mobile electric contact (18.2) is abutted against the fixed electric contact (13.2),

- a supporting element (14, 15) for said switching member (16), the supporting element (14, 15) being electrically conductive and electrically connected to the other of the two connecting terminals (11.1),
characterized in that
the switch (1) further includes an elastically deformable conductive element (30) interposed between the supporting element (14, 15) and said switching member (16) for ensuring the electrical continuity between said supporting element (14, 15) and said switching member (16).
The electric switch (1) according to claim 1, wherein the elastically deformable conductive element (30) is a laminar elastic element.
The electric switch (1) according to claim 2, wherein the laminar elastic element (30) has a curved, essentially U-shaped and V-shaped profile, and has a middle region (34) resting on the supporting element (14,15) and two side tongues (32,33) arranged on opposite sides relative to said middle region (34) and suitable to interfere with the switching member (16).
The electric switch (1) according to claim 3, wherein the operating mechanism (20) is such as to cooperate with interference with a first surface of the switching member (16) and wherein the side tongues (32, 33) are such as to interfere with the switching member (16) by co-operating with a surface of the latter which is opposite said first surface.
The electric switch (1) according to claims 3 or 4, wherein the middle region (34) of the laminar elastic element (30) has a lower width than the width of the two side tongues (32, 33).
The electric switch (1) according to claim 2, wherein the supporting element (14) includes a forward region (15) which acts as a rest point and fulcrum for the rotation of the switching member (16), and includes a backward region (31) that acts as the rest point for the laminar elastic element (30).
The electric switch (1) according to claim 6, wherein the supporting element (14) is a bar transversal to the switching member (16) and laminar elastic element (30), and wherein the backward region (31) is a recess of said bar.
The electric switch (1) according to claim 7, wherein the forward region (15) is essentially cusps-shaped.
The electric switch (1) according to any preceding claim, further comprising another connection terminal (11.1) and another fixed electric contact (13.1) that is electrically connected to the other connection terminal (11.1), wherein the switching member (16) is provided, at one other end thereof, with another mobile electric contact (18.1) and wherein this other mobile electric contact is abutted against the other fixed electric contact (13.1) in the other of the two preset positions of the switching member (16).
The electric switch according to any preceding claim, wherein the metallic jumper (16) has a middle portion (17) having a rounded profile and wherein said operating mechanism (20) includes a spring-loaded pin (29) which is slidably in contact with said middle portion (16).
The electric switch (1) according to claim 10, wherein the spring-loaded pin (29) and the switching member (16) are pivoting about axes that are parallel to each other.
The electric switch (1) according to any preceding claim, wherein said laminar elastic element (30) is made of phosphor bronze.
The electric switch (1) according to any preceding claim, wherein said laminar elastic element (30) has roundings at opposite two of the end portions (32, 33) thereof.