Patent GB-1041581-A (GB)
Title: A device for immobilising motor vehicles
IPC: B60R25/021
Filed: 1962-01-08
Abstract: 1,041,581. Locks. A. S. DWAN. Jan. 8, 1963 [Jan. 8, 1962], No. 623/62. Heading E2A. A device for immobilising vehicles comprises a housing 3 having a key operated lock 1, the turning of which by its key serves to operate means to immobilise the vehicle or to render it capable of use, the lock being mounted in its housing so as to be capable of movement in an axial direction of insertion of the key, the lock being constrained in its normal working position so as to be held therein against axial movement on insertion of the correct key, but moving if undue force is applied in that direction, which movement places the lock in an upset position such that rotation thereof cannot operate the means to render the vehicle capable of use. As shown, the lock 1 is mounted in a sleeve 2 which is slidable in a sleeve 4, a ball catch 4a in the sleeve 4 co-operating with one or the other of a pair of recesses 2b in the sleeve 2. A cam C is freely rotatable in a housing 7 about a D-section extension 1a of the lock 1 and is secured to a contact detent plate 6. A cam-dog 8 located on a square section extension 1b is received in a recess in the cam C and carries a spring-loaded movable contact plate 9 which co-operates with fixed contacts 9a adapted for connection to electrical circuits of the vehicle, e.g. ignition and starter relay circuits. An extension 3a of the housing 3 terminates in a yoke by which the device is secured to a steering column casing. A spring-loaded sliding bolt 15 is adapted to engage a slot in a steering column. The arrangement provides for on/off ignition and engine starting, and, in the event of undue pressure on the lock for instance by the use of an instrument or an incorrect key the lock and sleeve 2 will move axially to the position in which the ball catch 4a engages the detent 2b, in which position the cam dog 8 is disengaged from the cam C, and contacts 9, 9a are broken. The lock is reset by inserting the correct key and turning, a plate 5 turning therewith to align the lock and sleeve 2 to allow the key to be turned to the start or running position in which the key cannot be withdrawn. The key is then pulled forwardly and turned to the off position to re-align the cam dog 8 and cam C. The bolt 15 is slidable within a pair of concentrically mounted spring-loaded sleeves 18, 20 which abut against a lug 22 which is rotatable to load the spring 21 in torsion. The cam C operates on a plunger 23 which loads the sleeve 18 and the bolt 15. A radially extending pin 25, Fig. 3 (not shown), extends from this end of the bolt 15 through slots in the sleeves, and a control lever 26 is secured to the sleeve 20 and extends through a slot in the housing extension 3a. The arrangement is such that the cam C loads the bolt 15 and when the key is turned to the ON position, the cam C is rotated by the dog 8 to relieve the plunger 23 which with the bolt 15 is then forced inwardly by its spring 19. The pin 25 then passes a shoulder 20a which allows the sleeve 20 to turn to lock the bolt in retracted position. When the key is turned to the OFF position, the bolt is held by the pin 25, the springs 19 and 24 are loaded and the electrical circuits are broken. If the lever 26 is then moved to rotate the sleeve 20, the pin 25 is freed from the shoulder 20a and the bolt is projected. The arrangement is such that the electrical contacts cannot be remade, so long as the bolt 15 is in projected position.