MXPA98002073A - Multip retain membrane switch - Google Patents

Abstract

An improved membrane switch includes multiple seals. A pair of electrical circuits are completed with the membrane switch, and a pair of flex portions are located in said membrane. A first bending portion is overcome by a first minor insertion force in order to complete a first circuit, and a second bending portion is overcome only by an additional insertion force. The second flexion portion is eventually overcome and completes a second circuit. The membrane switch of the invention provides the operator with a clear indication and a sense of retention with respect to each of the two circuit

Description

MULTIPLE HOLDER MEMBRANE SWITCH BACKGROUND OF THE INVENTION This invention relates to a membrane switch of multiple seals, where at least two electrical circuits are completed with a single membrane switch. Electric switches are used in increasing amounts in modern vehicles. The operator of a modern vehicle is offered many different control options, and thus, more and more electric switches are needed. The vehicle switches have typically included several different mechanical parts, and the assembly has been somewhat slow and expensive. In addition, multi-piece mechanical switches have also sometimes been subject to failure. As an example, switches are known that can receive serial drive to indicate different desired functions of the switch. Window switches are known where a first actuation of the switch causes the window to move completely up or down. A second series actuation of the switch causes the window to stop at a desired intermediate position. The provision of this type of switch is quite complex and expensive.

One goal of all vehicle manufacturers is to decrease the complexity and cost of the components. Thus, less expensive and complex electrical switches are desired. Membrane switches are known where a membrane has a relaxed position in which it holds two electrical contact elements out of contact. The membrane switch has a flex zone that can be overcome by an operator in order to join the electrical contacts. Membrane switches have fewer operating parts than the mechanical switches of the prior art, and thus have some desirable characteristics. However, known membrane switches have only been used to drive single circuits, and thus have been used less widely than would be desirable. SUMMARY OF THE INVENTION In a described embodiment of this invention, a membrane switch includes at least two detents, or flex zones, such that it can selectively complete at least two circuits. This invention will be described with an embodiment that includes only two seals and circuits, but it should be understood that additional seals and circuits could be added. Regarding the novel features of this application, the membrane includes two bending portions, a first bending portion being overcome by an insertion force exerted on a button such that a first circuit is completed. As the operator exerts an additional insertion force, the second flexion portion is overcome and flexed to be able to complete the second circuit. Preferably, the second circuit is completed with electrical contact elements placed in a radially outer position in the membrane. In practice, an operator applies an insertion force to a switch button. Firstly, the first bending portion is exceeded, and the first contact element moves in contact with its coupling contact on a circuit board. So, the first circuit is complete. If the operator then wishes to close the second circuit, additional insertion force is exerted on the button of the switch, and the second bending portion is exceeded. The second contact element then moves into contact with its coupling contact element on the circuit board and the second circuit is completed. The multi-seal membrane switch of the invention provides the operator with a different sensing of the detent such that the operator receives a clear indication of when the first circuit is complete, and in addition to when the second circuit is complete. This is important, because the operator who only wants to close the first circuit must have an indication of when sufficient insertion force has been exerted on the switch so that the operator does not accidentally close the second switch. These and other features of the present invention can be better understood by the following specification and drawings, of which follows a brief description. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a view of the multiple seal membrane switch of the invention. Figure 2 represents the switch of figure 1 with a first closed circuit. Figure 3 represents the switch of the present invention with both circuits closed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A multi-seal membrane switch of the invention 20 is illustrated in Figure 1. A membrane 22 is provided with a button face 24. A first contact 26 is placed in a first flat portion 27 of the membrane 22. The contact 26 is placed on top of contact elements 28 formed on a circuit board 29. The button 24 extends through a housing 30, shown here schematically, and is accessible to the operator of a vehicle or other system carrying the membrane switch 20. Other types of joints can connect an operator switch with the button 24 so that the operator can operate the button. A second contact 31 is placed on a flat face 35 on the membrane 22, and spacing of the contacts 32 formed on the circuit board 29. The contact 31 is preferably placed on a center line of the button face 24. A first zone of flexion 33 is positioned radially outwardly of contact 26, and a second flexure zone 34 is positioned radially between contact 31 and contact 26. The switch of the invention is capable of controlling two circuits with a minimum of parts. The contacts are represented somewhat schematically, and it should be understood that contacts 32 and 28 would complete a circuit when contacted by contacts 31 and 26, respectively.

Figure 2 represents the first circuit closed by the switch of the invention 20. As shown, the button 24 has been pressed inwards with respect to the housing 30. The contact element 26 moves in contact with the contact 28. flexion portion 33 has been flexed to its flexed position 36. A first and less insertion force is required to reach this position. The design and manufacture of the flexing portion 33 that can be moved to a flexure position 36 as represented in this figure is well within the skill of an operator in the field of membrane switches. Single-seal membrane switches have been developed, and the known bending technology used is sufficient for the purposes of this invention. As shown in FIG. 2, the contacts 31 and 32 remain out of contact, and thus the second circuit is not complete. If the operator wishes to complete the second circuit, press the button 24 further inwards. The bending portion 34 moves to its bent orientation 38, and the contact 31 now contacts the contact 32. The second circuit has now been completed. The operator receives a clear indication of the completion of the first seal as shown in Figure 2, and knows when to stop the insertion if it is not desired to complete the second circuit. At the same time, the operator also receives a clear indication of when the second detent completes the second circuit. The switch 20 maintains the position shown in Figures 2 and 3 until the button 24 is released. Once released, the flex zones return the switch to the orientation of Figure 1. As an example of a potential use of the switch of the invention, the first detent and circuit can be used to make a window move to fully closed or open positions. The second circuit could be used to provide an indication that the operator would like the movement of the window to stop at an intermediate position. The use of the single membrane switch provides this dual switching capability with a minimum of parts and complexity of the required switching elements. It is preferred that the switch assembly be as shown in this drawing. The contacts 26 may be generally cylindrical rings or may be circumferentially spaced contacts. The first bending portion 33 is radially outward of the first contact 26. The second bending portion 34 is radially between the first contact 26 and the second contact 31. The second contact 31 is radially inward of the first contact 26. They have been described preferred embodiments of this invention; however, an operator with ordinary skill in the art will recognize that some modifications will fall within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention.

Claims (10)

1. CLAIMS 1. A membrane switch that includes: a membrane body having at least first and second flexion portions and at least first and second membrane contact elements, said membrane body being positioned adjacent to electrical contact elements of the circuit associated with each of said first and second membrane contact elements in said membrane body; and said first and second flexing portion normally pushing said first and second membrane contacting elements out of contact with said electrical contact elements of the associated circuit, and by first flexing a force exerted on said membrane switch said first portion of bending and making that said first membrane contact element contacts said electrical contact of the associated circuit, and making the insertion force additional that said second flexion portion flexes and allows said second membrane contact element to contact its contact element of the associated switch. A membrane switch as set forth in claim 1, wherein said second membrane contact element is positioned radially inwardly of said first membrane contact element. 3. A membrane switch as set forth in claim 2, wherein said first flexure zone is radially outwardly of said first membrane contact element. A membrane switch as set forth in claim 3, wherein said second bending zone is radially between said first and second membrane contact elements. A membrane switch as set forth in claim 1, wherein said second flexion portion requires a greater insertion force to flex than said first flexion portion, such that said first flexion portion is moved first to allow said first membrane contact element contacts its contact element of the associated circuit. A membrane switch as set forth in claim 1, wherein a button face is formed in said membrane body in a generally central position, said button face providing the operator with a position to apply an insertion force. A membrane switch as set forth in claim 6, wherein said second membrane contact element is aligned with the center of said button face. 8. A membrane switch as set forth in claim 1, wherein said electrical circuit contact elements are mounted on a circuit board. 9. A switching method that includes the steps of: providing a membrane switch having a first and second flexion portion and a first and second electrical membrane contact, said membrane switch being positioned adjacent to a circuit board, provided said circuit board of associated circuit electrical contacts for each of said first and second membrane electrical contacts; exerting an insertion force on said membrane to overcome said first bending portion and cause said first membrane contact element to contact said associated circuit contact; and exerting additional insertion force to overcome said second bending zone and causing said second membrane contacting member to move in contact with said associated circuit contact in said circuit board. 10. A membrane switch that includes: a membrane body having a first flexion portion positioned radially outwardly of a second flexion portion and a first membrane electrical contact element positioned radially between said first and second flexion portions, a second membrane electrical contact element positioned radially inwardly of said second flexion portion; a circuit board having first and second electrical circuit contact elements associated with said first and second electrical membrane contact elements, and placed next to said membrane body, said first and second membrane contacting elements being normally remote from said first and second circuit contact elements by said bending portions, and said first and second bending portions having insertion forces different necessary to produce bending in such a way that, upon application of a first minor force, said first bending portion is overcome and causes said first membrane electrical contact element to move in contact with said first electrical circuit contact, while said second bending portion still maintains said second membrane electrical contact out of contact with said second electrical circuit contact, and making an additional insertion force said second bending portion also flex and make said second electrical contact element membrane contact said second circuit contact to electric.