Huwil-werke Gmbh Mobelschloss Und Beschlagfabriken

Rolf Willach

An encoding circuit is provided permitting energization of an electromagnetic unlocking solenoid if a series of push-button switches is operated in accordance with a predetermined code. The circuit includes a memory which stores the sequence of operation of the push-buttons in accordance with the code in form of a binary code word. A comparison or decision stage is connected to the memory, typically a shift register, and connected to the memory position of all the digits of the code associated with the specific lock of a binary 1 value, as well as all the digits of the code in a binary 0 value, the decision circuit controlling the unlocking solenoid only if both the binary 1 and binary 0 values stored in the memory upon sequential push-button operation conform to the code associated with the lock, and, simultaneously, a timing circuit energized upon initiation of the first properly coded push-button still provides a timing energization signal, or operating energy to the circuit. In addition, the decision stage includes another input connected to a memory position, the value of which is unaffected by operation of the push-button switches so that additional safety against opening of the lock by trial-and-error operation of the push-buttons is provided.

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Au, Switzerland

Rolf Willach