| 摘要 |
A lock which is rekeyable or programmable to operate with a different key from the exterior thereof without disassembling it or removing it from a lock assembly in which it is assembled is disclosed. The lock is rekeyed by a change key through the keyway so that the lock appears from the exterior thereof to be a conventional lock. The change key which can not operate the lock adjusts a movable shear line formed by what is in effect an externally adjustable tumbler. The lock includes a plurality of pin tumbler sets and a plurality of cylinders disposed one in the other in the lock casing. The pin tumbler sets and the cylinders cooperate to from a plurality of common pin tumbler shear lines, i.e., shear lines formed by a number of individual shear lines of individual pin tumbler sets. In a given position of the adjustable shear line, only one of the keys will position the pin tumblers to form the proper common pin tumbler shear which is aligned with the adjustable shear line to operate the lock. The rekeying structure of the lock is passive and its presence is not noticed when operating the lock. The lock also includes structure which indicates that the adjustable shear line is in one of the position with which a common tumbler shear line may be aligned. The lock further includes structure which locks the adjustable shear line in a given position.
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