Motor vehicle theft-deterrent steering lock

A motor vehicle theft-deterrent steering lock (10) of the type comprising a casing (12, 14, 16) in which a lock (18) is mounted to rotate between an angular position of rest in which a compliant key (26, 30) can be introduced, from the rear forward, or withdrawn, axially, and at least one angular position of use in which the key (26, 30) cannot be extracted from the lock (18), the lock comprising a rotary deployment member (34) forming a cam which is capable of collaborating with a control member (110, 64) borne by a lock bolt (50, 78) to control the movements of the latter which is mounted so that it can slide in the casing (12), in an axial direction, between a forward theft-deterrent position toward which it is elastically urged and in which it projects axially forward through an opening in the casing to prevent the rotation of a member (56) of the steering column when the lock (18) is in the position of rest, with the key extracted, and a rear position in which it is retracted into the casing, and of the type in which:

• the lock bolt (50, 78) carries a retractable immobilizing finger (110) which projects radially toward an axis (A) to be housed in an immobilizing housing (120) formed in a lateral face (112) facing it belonging to the deployment member (34), of axial orientation, when the lock bolt (50, 78) is in the forward theft-deterrent position, to prevent or limit any movement of the lock bolt toward its retracted rear position;
• the immobilizing finger (110) automatically moves out of the way as the lock (18) is turned from its position of rest toward its position of use;
• and the lock bolt (50, 78) is held axially in the retracted rear position, in the presence of a key, by a lock bolt retaining member (92) which is mounted so that it can move between a retracted position, when the key is absent, and a retaining position when there is a key present,
• wherein the immobilizing finger (110) belongs to an immobilizing member (64, 110) carried by the lock bolt (78) with respect to which it is mounted to pivot, around a transverse axis (B) perpendicular to the axial direction of the sliding of the lock bolt, against the action of a return spring (84, 134) which constantly urges it angularly in the direction corresponding to the housing of the immobilizing finger (110) in the immobilizing housing (120).