Electricity: circuit makers and breakers – Fluid pressure – Diaphragm
Reexamination Certificate
2000-04-20
2001-07-24
Friedhofer, Michael (Department: 2832)
Electricity: circuit makers and breakers
Fluid pressure
Diaphragm
C200S061430, C200S242000
Reexamination Certificate
active
06265679
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a switching element, in particular a pressure-wave switch for safeguarding jamming points in the case of operable gates, doors or the like, having at least one pressure chamber which is provided at least partially with a diaphragm, it being possible to connect an exciter contact element for making contact with a consumer contact element via the diaphragm.
Such pressure-wave switches are known and can be obtained on the market in a wide variety of forms and designs. They serve essentially to safeguard jamming points, in particular in the case of operable doors, gates or the like. Use is frequently made of sealed rubber or hollow sections which are connected via a hose to a pressure-wave switch described at the beginning. Given a specific pressure on the hose when, for example, a door, a gate, window or the like is closed, a pressure is built up in the pressure-wave switch and an electric contact is closed between an exciter contact element and a consumer contact element. If the door is opened, the pressure in the pressure-wave switch subsides, the diaphragm retracts and an electric contact is interrupted. The latter conducts the corresponding signal, which can be further processed.
In this case, a contact element which is assigned to the diaphragm is moved linearly against a further contact element of a consumer contact element. Contamination and, in particular, wear phenomena frequently occur as a result with such pressure-wave switches. Through frequent operation, electric arcing forms a so-called insulating layer which greatly impairs the reliability of such a pressure-wave switch. Such switches are frequently moved, and so very high demands are placed on wear. These switches react, for example, in the case of an air overpressure in the system of approximately 2 mbar. Upon contact closure, a stop signal or a reverse signal can be passed on at the drive of the door or the gate.
The reliability of such pressure-wave switches is therefore of fundamental importance in safety engineering. Operations frequently proceed in this case with contact gaps and low contact pressures, resulting in contamination, oxidation of the contacts even in the case of low currents such as occur, for example, in driving digital circuits.
SUMMARY OF THE INVENTION
It is the object of the present invention to create a switching element, in particular a pressure-wave switch of the type mentioned at the beginning, which eliminates the said disadvantages, and with the aid of which permanent switching is possible in a simple and cost-effective and reliable way without contamination of the contact elements and without the formation of a corroding and insulating layer by electric arcing, and which is reliable in operation.
This object is achieved by virtue of the fact that the exciter contact element and/or the consumer contact element can be moved out of a contact plane in order to make common contact.
It is important in the case of the present invention that, when pressure is applied to the pressure-wave switch, the exciter contact element is moved against the consumer contact element by means of the diaphragm. The movement of the contact elements toward one another pushes the contact surfaces over one another. This is ensured permanently during switching on or off of an electric connection between the exciter contact element and consumer contact element.
It is important in this case that, as they engage on one another, at least one contact element is moved out with respect to the other contact element from a plane of the contact element.
This outward movement of the contact elements against one another from the contact plane is ensured by virtue of the fact that imaginary fulcrums of the individual exciter contact elements and of the consumer contact element lie outside the contact plane.
These imaginary fulcrums preferably lie in a diaphragm plane. In this case, the contact elements of the exciter contact element and of the consumer contact element lie outside the diaphragm plane. Only in this way is a permanently sliding movement of the contact elements toward one another ensured as they touch. In particular, this prevents an insulating layer from building up. In this case, as they engage one another and come out of engagement, the contact elements are always pushed over one another, with the result that the contact surfaces are freed from dirt and any possible corrosion is prevented.
Consequently, the present invention gives rise to a switching element, in particular a pressure-wave switch which operates in a maintenance-free fashion with a substantially enhanced reliability.
The scope of the present invention is also intended to cover the employment and use of the corresponding exciter contact element and of the consumer contact element in the case of an underpressure-wave switch. The exciter contact element then correspondingly reaches over the consumer contact element. This is also intended to be covered by the present inventive concept.
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De Jager Godert
Lexer Christof
Bachman & LaPointe P.C.
Bircher AG
Friedhofer Michael
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