Apparatus and method of rebroaching a lock assembly
OwnerJames A. Wattsinventor
Life of this patent
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Abstract
A previously used lock assembly constructed for operation using a given key may be operated by a different key after rebroaching. Instead of requiring an expensive, complete replacement of a lock assembly and its operable keys, the present invention allows a lock assembly to be refitted for a different key by a relatively inexpensive replacement of its plug and at least one of the tumbler components, preferably the bottom pin only, of one or more preexisting sets of tumbler components, as needed to modify the lock to receive the different key.
Claims7
A method of rebroaching a rotatable tumbler cylinder lock, said lock comprising a cylinder plug having a given longitudinal axis and rotatable within a cylinder shell about said longitudinal axis under control of a plurality of rotatable tumblers, said shell having a plurality of cylindrical pin chambers spaced along the length of said cylindrical shell, each of said cylindrical pin chambers being constructed and arranged to receive any one of said rotatable tumblers and having a preexisting broach oriented in a first common radial plane extending through said given longitudinal axis, said plurality of rotatable tumblers including at least one of said rotatable tumblers received in at least one of said cylindrical pin chambers, said at least one of said rotatable tumblers in at least one of said cylindrical pin chambers being provided with key-contactable surface means for allowing actuation of said at least one rotatable tumbler within said at least one cylindrical pin chamber to a key-contacting position associated with said at least one tumbler, said at least one tumbler comprising a preexisting set of components comprising a cap, a spring, a top pin and a bottom pin received within said at least one cylindrical pin chamber, said bottom pin having a flag extending radially outward therefrom and into a respective preexisting broach to define the orientation of said key-contactable surface means, said method comprising withdrawing said plug from said shell, removing said at least one rotatable tumbler from said at least one cylindrical pin chamber, rebroaching said at least one cylindrical pin chamber in said shell to define a second broach for said at least one cylindrical chamber along a second common radial plane oriented at a fixed angle to said first common radial plane, and reassembling within said at least one rebroached cylindrical pin chamber at least one component of a replacement set of components comprising a cap, a spring, a top pin, a bottom pin having key-contactable surface means of different configuration from that of said at least one rotatable tumbler, and a flag inserted to extend into said second broach, thereby replacing said preexisting set of components with said replacement set of components.
Dependencies are inferred from the claim text.