Anti-theft device for the steering column of an automobile

An anti-theft device for locking the steering shaft of a vehicle against rotation wherein the steering shaft extends colinearly through a hollow steering column and is mounted for relative rotation with respect thereto comprising, a crown gear mounted on said steering shaft by a mounting means so that it is rotatable with said steering shaft with respect to said steering column and rotatable with respect to said steering shaft through a predetermined arc, said crown gear comprising radially projecting teeth and concave sections between said teeth each having at least a partly circular profile, means to resiliently urge said crown gear into a median position within said predetermined arc, a locking element support member rigidly attached to said steering column, an elongated cylindrical locking spindle rotatably mounted in said support member with its longitudinal axis of rotation extending substantially parallel to said steering shaft, a control element operably engaging said spindle to impart and control the rotation thereof, a lock mounted on said support member operably engaging said control means to control the operation thereof, and a locking element on said spindle adjacent said crown-gear comprising a locking finger in the form of a segment of a cylinder rotatable with said spindle having a radially outer part circular face of substantially the same radius as said partly circular profile of said concave sections of said crown gear, said outer face being positioned with respect to said crown gear so that when said lock is in the unlocked position, said face and segment are entirely removed from engagement with said concave sections and teeth to allow rotation of said crown gear and when said lock is in the locked position, said face of said segment engages said partly circular profile of one of said concave sections to thereby prevent rotation of said crown gear and steering shaft.