Interlocking mech. for key inserted into lock in self-service units - prevents key withdrawal before completion of key-data reading

摘要

The use of coded keys in self-service units e.g. petrol-pumps has led to abuse by withdrawal of the key before its code has been read and recorded by the mechanism. The present interlocking device prevents this by holding an inserted key until a release mechanism is actuated. When the key is inserted into the lock barrel it strikes first against the release arm which rocks on its axis and lifts a locking piece with its opposite end. This is lifted away from the end of a pawl so that the end of the pawl can engage in a slot in the underside of the key as the latter moves forward. When this happens the locking piece rests on the other end of the pawl, so preventing key withdrawal until a releasing cam is rotated.