| 摘要 |
An electrical combination lock circuit providing output signals representing locked, unlocked and semi-locked states. An "unlocked" signal is produced by providing input signals in proper sequence representing the unlocking combination. The "semi-locked" signal is produced only by providing an appropriate input signal when the combination lock circuit is in the "unlocked" state. The semi-locked state may be used to allow limited access to the protected area. Provision of an input signal representing a digit that is out of sequence in the combination or that is not in the combination causes the circuit to return to the "locked" state. In each of the locked, unlocked and semi-locked conditions the lock circuit provides a momentary electrical signal, a continuous electrical signal and a contact closure or "continuity" state for use by external locking devices. The electrical combination lock has particular advantage in protecting an automobile. In the semi-locked condition limited use of the automobile is permitted, such as by a parking lot attendant. Multiple sets of combination input means may be employed to provide access to individual areas only such as to the ignition system, trunk or doors of an automobile. |
