US 4,045,629 AGranted

Electrical proximity switch arrangements

AssigneeBassani Ticione S.p.A.

InventorAlberto Anzani

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Abstract

An arrangement for modular mounting of a plurality of proximity switches comprises a plate of insulating material having a plurality of first conductive plates mounted on its front face. A respective housing containing a switch circuit is replaceably mounted to the rear face of the plate of insulating material in correspondence with each first conductive plate. Each housing contains a second conductive plate which, in conjunction with the associated first conductive plate, forms a parallel-plate capacitor. The dielectric of the capacitor is formed by the plate of insulating material, a flat wall of the housing which the second conductive plate lines, and an air gap between the plate and the flat wall. Touching of the second plate by a user varies the capacity of the capacitor thus generating a signal operating the circuit within the housing. Since the two plates of the capacitor are mutually isolated, the user cannot experience an electric shock. The housing may be mounted in the rear face of the plate of insulating material either direct or by way of an intermediate supporting frame.

Claims7

Dependent claims

A proximity switch arrangement, comprising a support constituted of electrically-insulating material and having a front and a rear surface;

a modular unit having a wall constituted of electrically-insulating material and facing said support;
proximity switching means, including actuating means having an electrically-conductive touch plate fixedly mounted at said front surface of said support so as to remain substantially stationary relative to the latter when contacted by a user to thereby generate a signal indicative of such contact, detecting means having an electrically-conductive plate mounted at the inwardly-facing side of said wall which faces away from said support and operative for detecting said signal, and means responsive to said detecting means for initiating transmission of said signal;
mounting means for juxtaposing said plates in substantial spaced parallelism by mounting said unit on said supprt, to thereby form a capacitor with the electrically-insulating materials serving as the dielectric, said electrically-insulating materials being operative for maintaining said plates apart and for maintaining said touch plate away from said transmission initiating means to thereby obtain maximum user safety.

Dependencies are inferred from the claim text.