A PUSH BUTTON DEVICE FOR ELECTRIC CONTACTS OR THE LIKE PARTICULARLY SUITABLE FOR INSTRUMENTATION PANELS

Abstract: A push button device for electric contacts or the like, partic­ ularly suitable for instrumentation panels, comprising a fixed annular body (2), a movable body (1) which is external to said fixed body (2), two small cylinder-shaped means (6) of a conductive material which in the rest position (6a) are intermediate between said fixed body and said movable body and, in the contact operative position (6b) are adjacent to the base of said shaped body, said device also comprising at least an elastic return spring (10) connected to the ends of said small cylinder-shaped means (6).

Description: The present invention relates to a push button device for electric contacts or the like, particularly suitable for instrumentation panels. More particularly, the present invention relates to a device of the kind mentioned above, which device controls a system of springs and small cylinders through the axial movement of a push button, said springs and cylinders, by moving in turn axially, realizing the contact with an electric or a printed circuit. A number of solutions have been proposed and realized in the technical field in which the devices of the type the present invention deals with are employed, but said solutions, though sufficiently reliable for the desired uses, give rise to a series of drawbacks that make it difficult to employ the same. More particularly, the push button device MARK 21 of JAY-EL PRODUCTS, INC. is characterized by the lack of tactile sensation on the user's part. Such drawback has been overcome by the device of SYMBOLIC DISPAYS, INC., which are realized employing a synthetic material bulb. Such type of solution shows a tendency to frequent breakage so that it cannot be considered reliable. Another kind of solution adopted makes use of a contact bearing a printed circuit realized direct on said contact, on a very small area of the same, so that a very large deterioration of the contact points occurs. Moreover, in the case of such solution the tactile sensation is completely lacking. One of the most advanced systems known (US-A-4,088,855 for Korry Manufacturing Company) in the technical field makes use of an an annular spring which, by moving axially and laterally under the pressure of a button, realizes the contact. In that way, though the user has the tactile sensation of pushing the button, the danger of device failure if the spring breaks is not completely eliminated, and, in addition, as said spring is in direct contact with the printed circuit, even though on a larger area, it tends to wear said circuit, so that the risk of device failure increases. In DE-A-3313557 a push button device to close and/or open electric contacts is described. Said device comprises a fixed body and an axially movable body sliding within a hole realized in said fixed body. Around the fixed body a circular spring is provided which engages with the movable body and acts on flexible reeds by the action of the same movable body. Under said reeds, a circuit board is provided. The push button device according to the present invention proposes to obviate to these and other drawbacks, said device allowing a safe employment also in the case of breaking of one of said components of the contact mechanism, through a contact mechanism consisting of a number of components, and in addition supplying the operator with a sharp tactile sensation of the push button tripping when it is pressed. Moreover, because of the presence of an elastic reed of conductive material, interposed between said components of the contact mechanism and the printed circuit, the wearing is also advantageously avoided of said printed circuit, with a consequent increase in the factor of safety. A further object of the present invention is that of providing a push button device whose contact members are self-cleaning. It is a further object of the present invention that of providing a device bearing a push button which is able to realize the contact, on one or more circuits indifferently, said circuits being arranged respectively on the sides of the slider, as a result of a particular configuration of a rocking arm. It is a further object of the present invention that of providing a push button device which, in its various kinds of embodiment, is provided with contacts which are able to close indifferently a single contact or a multiple-throw contact, two or four independent contacts or two contacts which are independent of one another. Such features make thus the device according to the present invention suitable for the employment in a number of different instrumentation types, including the aeronautical instrumentation which requires a very high efficiency and a very high factor of safety of each device. Accordingly, a specific object of the present invention is to provide a push button device for electric contacts, particularly suitable for instrumentation panels. Such a device according to the invention comprises an annular shaped, fixed body bearing an outwardly extending step at its base; an axially movable body telescopically slidable over said fixed body, and is characterized in that a printed circuit is provided under the fixed body; two small cylindershaped means made of a conductive material are provided between said step and an annular striking zone of said movable body in the rest position and adjacent to the base of said fixed body in the contact operative position; and in that at least one elastic return spring means is provided transversely to said cylinder-shaped means between their ends respectively. According to a preferred embodiment of the device according to the present invention, two elastic return spring means can be provided, which are connected to the ends of said small cylinder-shaped means. Again according to a preferred embodiment of the present invention, said elastic conductive reed means consist, at the points corresponding to the area of contact with said small cylinder-shaped means, of portions at a slope with respect to the plane of the printed circuit, said portions being oriented towards said small cylinder-shaped means so as to allow an elastic electric contact with said printed circuit to be realized. Moreover, again according to a preferred embodiment of the present invention, guiding means can be provided for said spring means on one or on both the sides perpendicular to the position of said small cylinder-shaped means. Moreover, according to a further embodiment of the present invention, the upper part of said axially movable body external to said fixed body is made up of a light transparent material, so that at least one illuminating means can be provided inside said device. Advantageously, said elastic reed means interposed between said small cylinder-shaped means and a printed circuit protect said circuit from wear. Further according to a preferred embodiment of the present invention, the tactile sensation given by the tripping of said push button device can be sensed by the operator when said small cylinder means go in their axial motion beyond the step-shaped part of said fixed annular body. Moreover, another embodiment of the present invention provides a push button device for electric contacts or the like, particularly suitable for instrumentation panels, in which said fixed shaped annular body bears at its lower part a concave bevelled step and said movable body having a shaped annular striking zone; in correspondence to each of said small cylinder-shaped means, said zone projecting downwards and has bevelled edges both inside, towards said fixed body, and outside, said movable body acting, through said annular striking zone, in cooperation with said step, on said small cylinder-shaped means so as to cause the same to rotate and to translate horizontally. Further again according to a preferred embodiment of the present invention, a stop device can be provided for stopping the stroke of said movable body so as to have the possibility of assembling the push button according to the present invention with a single operation without the need for further supporting systems. In addition, reed means made up of a conductive material can be provided at a position between said small cylinder-shaped means and the printed circuit. According to a particularly preferred solution embodying the push button device according to the present invention, said movable body is able to perform rocking motions with respect to said fixed body, around the central axis of the push button, so as to have the possibility of providing alternately one contact each time. Again according to a preferred embodiment of the present invention, said small cylinder-shaped means can be made up of one only member consisting of a conductive material, said member being capable of realizing the electric contact on a single-throw or on multiple-throw simultaneously, or said small cylinder-shaped means can be made up of two conductive members provided over a core consisting of an insulating material, so that said spring means do not cause said two small cylinder-shaped means to go into contact, and so that each one of the same can thus close at least two separate contacts. Moreover, said small cylinder-shaped means can also consist of a core made up of an insulating material on which two separate conductive members are provided, but in contact with said spring. Preferably, said insulating material is made up of an indeformable insulating resin. The present invention will be disclosed in the following according to specific embodiments of the same with reference to the enclosed drawings wherein: Figure 1 is a cross section side view of the device according to the present invention, excluding said reed means which are not shown in order to illustrate the operation of said device; Figure 2 is a cross section side view of the device according to a preferred embodiment of the present invention; Figure 3 is a top plan view of the device illustrated in Figures 1 and 2; Figure 4 is a cross section side view of the device according to a preferred embodiment of the present invention; Figure 5 is a side view of a second embodiment of the device according to the present invention; Figure 6 is a side view of a third embodiment of the device according to the present invention; Figure 7 is a perspective view of a first embodiment of the small cylinder-shaped means of the device according to the present invention; Figure 8 is a perspective view of a second embodiment of the small cylinder-shaped means of the device according to the present invention; and Figure 9 is a perspective view of a third embodiment of the small cylinder-shaped means of the device according to the present invention. More particularly, number 1 in Figure 1 points out an axially movable body which is external to a fixed body 2. Number 3 points out a closing member which is made up of a light transparent material and is the upper part of the device according to the present invention, and it is also suitable for being assembled over said device through the fixing system pointed out as 4. By exerting a pressure on the member 3, the body 1 is caused to move axially, said body giving rise, through the annular striking zone 5, to an axial and lateral shift of the two small cylinders 6 which consist of a conductive material, from an initial rest position such that shown in 6a up to a final position 6b in which said small cylinders 6, after passing the step 7 of the member 2, realize according to the present invention an electric contact with a printed circuit 8 by means of said elastic reed means 9 (shown in Figure 2) provided at a position between said small cylinders 6 and said printed circuit 8. As soon as the pressure on the member 3 is released, the springs 10 connected to one or to both of the ends 11 of each of said small cylinders 6, as shown in Figure 3, reset the device to its starting configuration by returning said small cylinders 6 to the position 6a simply as a result of the elastic return force. A slidable body 12 of the push button of Figure 4 moves in the axial direction with respect to a fixed body 13. The closing member 14 consisting of a transparent material, assembled with said body 12 by means of the fixing system 15, is provided at the upper part of said body 12. The slidable body 12 presents at its lower part an annular striking zone 16 of a suitable shape. Indeed, at a point corresponding to the interference zone with said small cylinders 17, said annular zone presents a projecting part 18 with bevelled edges both inside, i.e., towards the fixed body 13, and outside. The cooperation of said projecting part 18 with the beveling of the step 19 of said fixed body 13 results, when the action is exerted on the closing member 14, in a rotation impressed to said small cylinders 17 around their axes till the position 17a as well as a translation to the position 17b. Such motions of said small cylinders 17 make them self-cleaning, so that the device according to a preferred embodiment of the present invention is given a higher reliability and operation warranty. Indeed, it is well known that even a few particles of dust can cause a poor reliability of the contact between the small cylinders 17 and the printed circuit 20. Said two small cylinders 17 are connected at their ends by the springs 21 (see Figure 5). A number of reeds made up of a conductive material (not shown) can be provided between said small cylinders 17 and the printed circuit 20. The embodiment illustrated in Figure 5 provides a special guide 22 that can be locked on the fixed body 13 of the push button according to the present invention so as to allow the same to be employed in a single assembling operation with no need for guiding the same by means of further supports. The push button according to a preferred embodiment of the present invention is shown in Figure 6, said button having the closing member 14 divided into two half-member 14' and 14''. The assembly consisting of said member 14 and of the sliding member is realized so as to be able to rock in a bascule-like way with respect to the central axis, so that it can close alternately the contact with one of the two small cylinders or with the other one. The position 23 of the member 14 for closing the right contact of the push button according to an embodiment of the present invention is shown in the same Figure. Figure 7 shows the small cylinder 17 realized by means of a single metal piece that can thus realize one or more electric contacts simultaneously on the printed circuit 20. According to the embodiment shown in Figure 8, the small cylinder 17 is realized employing an insulating material core 24, for example a core made up of an indeformable resin, on which two small cylinders 25 consisting of a conductive material are mounted. Thus, said two insulating material small cylinders 17 are insulated with respect to each other as said cores 24 are in contact with the springs 21, so that it is possible to act with a single switch on two or four electric contacts which are independent of one another and have a single or a separate common member. A further embodiment of the present invention is shown in Figure 9, in which embodiment said small cylinder 17 consists of two parts 26 made up of a conductive material arranged around an indeformable insulating resin core 27. Such an arrangement gives the possibility of breaking two contacts which are independent of each other, and have a single or separate common member, as said springs 21 join two by two said conductive members 26 of the small cylinders 17.

Claims: A push button device for electric contacts, particularly suitable for instrumentation panels, comprising an annular shaped, fixed body (2,13) bearing an outwardly extending step (7,19) at its base; an axially movable body (1,12) telescopically slidable over said fixed body (2,13), characterized in that a printed circuit (8,20) is provided under the fixed body (2,13); two small cylindershaped means (6,17) made of a conductive material are provided between said step (7,19) and an annular striking zone (5,16) of said movable body (2,13) in the rest position and adjacent to the base of said fixed body (2,13) in the contact operative position; and in that at least one elastic return spring means (10,21) is provided transversely to said cylinder-shaped means (6,17) between their ends (11) respectively. A push button device for electric contacts according to claim 1, wherein two elastic return spring means (21) are provided transversely between the small cylinder-shaped means (6,17) at each end (11). A push button device for electric contacts according to claim 1, characterized in that conductive elastic reed means (9) are provided between the fixed body (2,13) and the printed circuit (8,20). A push button device for electric contacts according to claim 3, characterized in that said conductive elastic reed means (9) are bent upwards and are made up, at the area corresponding to the contact zone with said small cylinder means (6), of portions which are at a slope with respect to the plane of the printed circuit (8), said portion being oriented towards said small cylinder means (6). A push button device for electric contacts according to claim 1, in which device guiding means are provided for said spring means (10) on one side or on both sides perpendicular to the axes of said small cylinder means. A push button device for electric contacts according to claim 1, said device being characterized in that the upper part of said movable body (7) is made up of a light transparent material, and at least one illumination means is provided inside the device. A push button device for electric contacts, according to claims 1 or 2, characterized in that said annular shaped fixed body (13) bears at its lower part a concave bevelled step (19), and said movable body (12) has an annular shaped striking zone (18) in correspondence to each of said small cylinder means (17), said zone (18) projecting downwards and having bevelled edges both internally, towards the fixed body (13), and externally. A push button device according to claim 7, said device being characterized in that a stopping device is provided to stop the run or stroke of said movable body (12). A push button device according to claim 7, characterized in that said movable body (12) is able to perform rocking motions with respect to the fixed body. A push button device according to claims 7 or 9, said device being characterized in that said cylinder means (17) are made up of a single conductive material member. A push button device according to one of the claims 7-9, said device being characterized in that said small cylinder means (17) consist of an insulating material core (24,27) which is in contact with said spring (21) means, as well as of two separate conductive members (25,26) provided on said insulating material core. A push button device according to one of claims 7-9, said device being characterized in that said small cylinder means (17) are made up of two separate conductive members which are respectively in contact with said spring (21) and are provided on an insulating material internal core. A push button device according to claims 10, 11 or 12, characterized in that said insulating material consists of an indeformable insulating resin.

Inventors: FORZIERI, GRAZIANO
Applicants: SIRIO PANEL S.N.C. DI FORZIERI G. E S.
Application year: 1986
Main classification: H01H13
IPC codes: H01H13