Abstract: A cylinder assembly for a plate tumbler lock includes a removable, self-retained plate tumbler which snap-fits into an assembled position by pivoting the tumbler and pushing the tumbler into its ward until a projecting detent passes by a retaining ledge in the side wall of the ward. The force of the tumbler spring then pivots the tumbler into its assembled position where the detent is engaged with the retaining ledge. The pivoting of the tumbler is accomplished by locating the leg which forms the tumbler spring seat on the tumbler in a position where it does not interfere with the terminal edge which defines the open top of the ward during assembly.

Abstract: A device for preventing the undesired rotation of a key and cylinder within a sleeve of an automobile steering column ignition assembly. The device prevents rotation of a key from an off position to a lock position, and the consequent locking of the steering wheel, unless an adjacent button is depressed. Rotation is prevented by the interference of a blocking element on the button itself with an end face of a flange projecting from a cap covering the outer end of the cylinder.