The present invention relates to electric switches, and more particularly, a push-button switch.
A switch of this type, as described for example in the Italian Patent Application IT RM2003A00018, includes a supporting structure made of insulating material having a box-like shape and defining an inner chamber for housing and holding the electromechanical components composing the switch. The supporting structure has an open side through which the inner chamber communicates with the outside of the box-like structure. In addition, the switch includes a push-button to be matched with the box-like structure to close the open side thereof. This push-button consists of a plaque provided with four coupling tongues suitable to be attached to opposite side walls of the box-like supporting structure to mechanically couple the push-button to the box-like supporting structure. By the mechanical coupling between the push-button and the box-like supporting structure, the push-button can slide in a relative and guided manner with respect to the box-like structure. This sliding movement is required to command an electric switching of the switch by means of the push-button.
It has been noted that in the prior art switches of the type described above, the sliding coupling between the push-button and the box-like supporting structure generates a drawback due to the fact that when the push-button is biased by pressure forces applied in a distinct point from a substantially middle portion of the plate, the push-button is inclined and tends to rotate relative to the supporting structure rather than axially translate relative thereto, thereby a loss in the sliding coupling is determined between button and structure which results in the switch being blocked, either temporary or permanently. In practice, this blocking is due to the push-button jamming against the supporting structure.
This drawback is particularly felt in several applications, for example in the lighting installations for dwellings and offices, in which the switches have a plaque having a plan considerably larger than a human finger, such that when push-button switches are operated in low light, a pressure is frequently applied to a point other than the middle of the plate.
The object of the present invention is to propose a switch operated by a push-button, which is such as to solve the problem described above with reference to the switches of the prior art.
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 a particular embodiment, 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:
a and 3b show an axonometric view of a detail of the switch from
a-4d schematically show the operation of the switch from
In the figures, equal or similar elements will be designated with the same numerals.
In
In this description, by the term “switch” is meant 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 switch, which is depicted in
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, the outside of the supporting structure 2. In
In the particular example as illustrated in the figures, the supporting structure 2 is practically an open box-like structure, i.e. it does not have a wall counter-posed to the bottom portion 7, the latter being counter-posed to the opening 9.
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 contains three connection terminals 11.1, 11.2, 11.3, 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
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 towards the opening 9 in a substantially central position relative to the fixed electric contacts 13.1, 13.2.
The push-button switch further includes an oscillating switching body suitable to establish electric connections, which in this particular example is embodied by a pivoting metallic jumper 16. In the example, the pivoting jumper 16, is shaped as a rocker arm with a central rounded profile and is located in the inner chamber 8 of the supporting structure 2 pivotally about an axis a1 orthogonal to the greater walls 5 and 6. The 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 18.8, 18.2 at the ends thereof. The jumper 16 is such that it can be moved to rotate about its central seating part in order to establish electric connections.
The push-button switch further includes a control mechanism 20 to be associated with the bearing structure 2 at the opening 9 thereof.
The control mechanism 20 includes a push-button 21 and means for mechanically couple the push-button 21 to the supporting structure 2 such that the push-button 21 is fastened to the supporting structure 2 while being movable relative thereto in a substantially parallel direction to the opening axis Z-Z. In greater detail, these mechanical coupling means advantageously include a holding and guide frame 22 for the push-button 21. The holding and guide frame 22 can be preferably though not exclusively snap fixed to the supporting structure 2. More preferably, the holding and guide frame 22 can be keyed within the opening 9 to be at least partially received within the inner chamber 8 of the supporting structure 2.
Preferably, the push-button 21 includes an upper portion formed by a key 23 and comprises a lower portion formed by push-button side walls 21a, 21b, 21c protruding from the key 23 towards the opening 9, substantially parallel to the axis Z-Z of said opening. In
Advantageously, the holding and guide frame 22 comprises side walls 22a, 22b, 22c annularly developing about the push-button 21 to envelope the side portion 22a, 22b, 22c of the push-button 21. In
In a particularly advantageous embodiment, the frame side walls on the side facing the push-button have surfaces, provided with projections and recesses being substantially counter-shaped relative to corresponding surfaces of the push-button side walls facing the holding and guide frame 22. Practically, projections of the frame side are received in corresponding recesses and vice versa, thereby defining a plurality of guides provided in the thickness of the frame and push-button side walls.
Advantageously, the push-button 21, due to the interaction between the push-button side walls and the frame side walls, is slidingly embedded in the holding and guide frame 22 such as to be able to translate relative thereto in a substantially parallel direction to the opening axis Z-Z in a guided manner. In particular, the push-button 21 can translate by sliding within the holding and guide frame 22 through a stroke comprised between a first limit position, as illustrated in
In a particularly advantageous embodiment, the push-button 21 and frame 22 form a directly assembled kinematism consisting of two pieces being almost irreversibly coupled to each other, i.e. they cannot be separated from each other in an easy manner or without damaging the structure of these pieces. For example, the push-button 21 and the holding and guide frame 22 are made of two distinct materials that cannot be chemically adhered, by means of an insert-moulding technique comprising two consecutive sequential injections. An insert-moulding technique of this type is, for example, described in the European Patent Application published as EP 1386716.
In a particularly advantageous embodiment, the push-button side walls include end-of-stroke projecting members 25 which protrude from the push-button side walls to corresponding frame side walls. In the thickness of these frame side walls there are provided pockets (i.e. blind cavities) or windows (i.e. through openings) 25 suitable to receive these end-of-stroke projecting members. In
With reference to
In an alternative embodiment, the end-of-stroke projecting members can be provided on the frame walls and the cavities suitable to receive these members in the thickness of the push-button side walls.
With reference to
The push-button switch further includes thrust elastic means suitable to hold the push-button 1 in its distal position relative to the frame 22, and thus distal relative to the supporting structure 2. This distal position is the rest position of the push-button 21. In the example as illustrated in
As illustrated in
In a particularly advantageous embodiment, the block 28 is pivotally mounted to the holding and guide frame 22 about an axis a2 substantially parallel to the axis of rotation al of the jumper 16. More particularly, on two opposite frame side walls 22c, 22d there are provided two opposite holes 40, one of which is seen in
The pin 29 has a rounded tip and is biased by a spring (not seen in the figures) being compressed in a cavity of the block 28 in order to provide an elastic connection between the block 28 and the underlying metal 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 with substantially step-shaped surfaces 32, which are substantially symmetrical relative to a plane containing the axis of rotation a2.
The control mechanism 20 further comprises, a pressure transmission means 33, illustrated in phantom in
More particularly, on two push-button opposite side walls 21c, 21d there are provided two opposite holes 50, one of which is seen in
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 plate 23.
With reference to
Prior to each switching of the switch, the button 21 is in its rest position (distal position from the frame 22) at a certain distance from the supporting structure. The transmission means 33 is also in the rest position, with its symmetry plane being substantially coincident with the plane containing the axes of rotation a1, a2 and a3, for the elastic action of the foil spring 36a, 36b, which in this embodiment of the invention is made as one piece. Simultaneously, the block 28 of the control member 27 and the jumper 16 are inclined in one of the their two stable angular positions. For example, such as shown in
For the symmetry relative to the plane passing through the axes of rotation a1, a2, a3, of the various pivoting parts, a further pressure applied to the key 23 brings both the block 28 and the jumper 16 back to the positions they occupied prior to the first switching, i.e. with the block 28 inclined to the left and the jumper 16 inclined to the right, such as shown in
From the above description, it is understood how the switch in accordance with the invention fully achieves the pursued object.
Advantageously, it should be noted how the provision of a holding and guide frame 22 being interposed between the button 21 and the supporting structure 2 allows avoiding the jamming problem occurring with the prior art push-button switches. This frame 22, in fact, prevents the push-button 21 from rotating.
Advantageously, providing the assembly consisting of the holding and guide frame 22 and the push-button 21 by means of an insert-moulding technique, allows providing an assembly of sliding parts with very high size tolerances, thereby the translation movement of the push-button 21 relative to the frame 22 is made even more accurate.
Advantageously, the provision of members 25 projecting from the push-button side walls and such to be received in corresponding pockets or openings 24 provided within the thickness of the frame side walls, allows obtaining end-of-stroke means having a negligible size within the room 8 of the supporting structure 2.
Advantageously, the provision of pivotally mounting the pressure transmission means 33 to the push-button 21 and pivotally mounting the control member 27 to the holding and guide frame 22 has a first advantage in that it makes the operative coupling between the pressure transmission means 33 and the control member 27 more accurate. Advantageously, this provision further allows to have a room 8 with a low depth. Furthermore, this provision advantageously allows to greatly simplify the switch assembly operations.
Obviously, to the push-button switch as 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.
Number | Date | Country | Kind |
---|---|---|---|
RM2005 A 000163 | Apr 2005 | IT | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/IT06/00218 | 4/3/2006 | WO | 00 | 12/12/2007 |