Abstract: A locking device comprises a lock cylinder and a reversible flat key having indentations located on opposite broad faces of the key for the arrangement of tumbler pins, and having a rib associated with each row of indentations, into the sectional area of which at least one of the pins extends and the crest of which rib projects beyond the broad face of the key. The deepest reached indentation lies nearest to the crest of the rib and several indentations of a row of indentations are integrated into a through groove of variable depth levels.

Abstract: A device for protecting motor-vehicles against theft comprising a freely rotatable sleeve covering the polygonal head of a wheel nut or screw, into which sleeve a cylinder lock engages rotatably, which lock is provided with at least one tumbler entering the inner wall of a cylinder lock location cavity of said polygonal head which projects beyond the circumference of said cylinder lock. In the locking position, said tumbler engages behind a cooperating locking shoulder which is located on an annular body inserted into an axial chamber of said polygonal head and locked in position thereto.

Abstract: For increased security the key (2; 40; 44) has one or more blade portions (43; 45; 46; 5, 6). The longitudinal central plane (A, B) of the or each blade portion is offset from the guide region (42; 7) running along the back edge of the key shaft (3). Furthermore, the or each blade portion is connected to the guide region by means of a bridging portion (14, 14') which forms an obtuse angle (alpha) with the guide region, as well as forming an obtuse angle with the blade portion. In one preferred embodiment two blade portions (45, 46; 5, 6) are provided; they may be of the same cross-sectional shape (FIG. 2) or symmetrical (FIG. 11). The blade portions and guide region may be divided into two portions to provide partner keys (FIG. 12).

Abstract: A switching device to be operated by means of a cylinder lock, comprising a switching element mounted for rotation on the core of the cylinder lock. Said switching element is adapted to move a spring-loaded contact pin from its operating position in contact with the actuating surface of an electrical switch and to lock it against returning to said operating position.