Patent ID: 7905125

Claim:
A changeable lock assembly that can be reconfigured to operate with different keys of a set of user keys, without disassembling the lock, comprising: a) a housing having a cylindrical bore with an inner surface and a plurality of driver chambers intersecting the inner surface; b) a plurality of drivers, each driver being movable within one driver chamber and being urged toward the bore surface; c) a plug having a cylindrical periphery and rotatably mounted within the bore so as to form a shear line at the interface of the bore surface and the plug periphery, the plug having a front end and a rear end and being rotatable between a first rotated position and a second rotated position, the plug further having: 1) a longitudinal axis; 2) a keyway formed through the front end of the plug that is oriented parallel to the longitudinal axis and configured to receive a key selected from a subset of keys, the subset of keys including at least a first user key having a first contour edge, and a second user key having a second contour edge, wherein the first contour edge and the second contour edge each have at least a first contour position and a second contour position and are differently configured; 3) a plurality of tumbler chambers intersecting the plug periphery and the keyway, each tumbler chamber being aligned with a driver chamber when the plug is at the first rotated position with respect to the housing so as to form a pin chamber; and 4) a plurality of retainer cavities formed into the periphery, each retainer cavity being spaced apart from a corresponding tumbler chamber and aligned with a corresponding driver chamber when the plug is at the second rotated position with respect to the housing; and 5) a change tooling configured integrally with the plug, and comprising a plurality of biasing surfaces, each of said plurality of biasing surfaces associated with one of the plurality of retainer cavities, the change tooling being moveable by manipulation only between a first position within the plug and a second position within the plug; d) a plurality of tumblers, each tumbler being movable within a tumbler chamber; e) a plurality of lock configuration change balls, each ball being associated with one pin chamber and one of the plurality of retainer cavities, and being movable within the lock between a first position within the associated pin chamber between the driver and tumbler, and a second position within the associated retainer cavity, wherein the user configuration of the lock is based upon the positioning of the change balls in the plurality of pin chambers, wherein each of the plurality of retainer cavities retains the associated change ball, if disposed in the second position, when the change tooling is in its first position, and each of the plurality of biasing surfaces has displaced the associated change ball, if disposed in the second position, from said associated retainer cavity when the change tooling is in its second position.