Lock assembly

Abstract

A cylindrical lock assembly is provided which is approximately the same size as present-day cylindrical "Mortise" locks, and which can replace present-day locks in the doors of hotels, motels, or other establishments, merely by removing the existing lock cylinders and replacing them by the lock cylinders of the invention. The lock assembly of the invention has a number of internal logic ring members which are mounted tandem to one another in coaxial relationship with the central axis of the lock, and which are replaceable to change the key pattern to which the lock will respond. The lock also includes a plurality of spring-biased tumblers, which are moved longitudinally to mating positions with respect to the various logic ring members when the proper keys are inserted in the lock. Each lock will respond, for example, to four different keys, namely, a guest key which is usually different for each lock in the establishment, a maid's key which fits a predetermined number of locks in the establishment, and an emergency key which not only fits all the locks in the establishment, but which can operate all the locks, even when a door is bolted by the usual dead bolt mechanism. In the embodiment to be described, the logic ring members can be changed only by a release operation which can be carried out only by the emergency key.

Dependencies are inferred from the claim text.