Patent GB-1292022-A (GB)
Title: Improvements in or relating to vehicle anti-theft devices
Inventor: ROGERS WILFRED DAVID
IPC: B60R25/021
Filed: 1968-10-12
Abstract: 1292022 Anti-theft devices WILMOTBREEDEN Ltd 9 Oct 1969 [12 Oct 1968] 48475/68 Heading B7J [Also in Division E2] A vehicle anti-theft device has a housing 9 with an operating shaft 4 rotatable therein, a slide 1 movable transversely of the shaft, a rotary cam 3 on the shaft for moving the slide, and a key-operated lock structure 13 with a portion 15 adapted to be turned by the key to rotate the cam, the housing also having a mounting for a switch mechanism 12 to engage and be driven by the shaft, the key and the keyturned portion of the lock structure being rotatable through successive angles from a vehicle-locking position, in which the slide itself, or a member carried or controlled by the slide, projects as a bolt from the device, first to retract the slide and then to take up positions usable for switching purposes, wherein the lock structure is depressible in the housing and is associated with means for preventing the key from being turned back directly from the switching positions to the locking position and which comprise two detents 18, 27 each axially depressed by depression of the lock structure, the first of said detents 18 turning with the key to engage an abutment 25 in the housing in turning from the switching positions and to clear that abutment when depressed, the second detent 27 fouling an abutment portion of the cam in the event of an attempt to turn the key to the locking position after depression of the lock structure before the first detent reaches its associated abutment. In the construction shown the slide 1 which acts as a bolt is urged by a spring 2 to the locking position and from which it is displaced by the cam 3. The shaft 4 on which the cam is mounted passes through a slot 5 in the slide above a web 6 which is pinned to the remainder of the slide and which projects in the direction of the lock structure 13; the cam 3 acts on the projecting portion of the web 6 and itself is rotated by the portion 15 of the lock structure to which it is coupled. The portion 15 of the lock structure has a projecting central stem 16 which is of non- circular section and it telescopically engages within a central projection 17 of the cam 3 thus allowing the lock structure 13 to be depressed while remaining rotatably coupled to the cam 3 and through the shaft 4 to the switch mechanism 12. The portion 15 of the lock structure has an intermediate "off" position from which it can be turned by the key through 30 degrees in one direction to an "ignition" position and to a further 30 degrees to a "start" position from which it is spring-returned to the "ignition" position when the key is released from the "off" position. The key can be turned through 30 degrees to an "auxiliary" position in which the switch mechanism 12 energizes various auxiliary circuits and it can be turned through a further 60 degrees beyond the "auxiliary" position to a "lock" position from which the key is withdrawn when it is desired to leave the vehicle locked. The detent 18 is telescopically but non-rotatably mounted on the cam projection 17 so that it moves axially with the lock structure 13 and turns with the cam 3. It has an outer end flange 22 formed with a radially projecting tongue 23; the flange 22 engages a shoulder of the inner portion 15 of the lock structure 13 so that a return spring disposed between the flange and the cam serves to return the structure after the latter has been depressed. The abutment 25 is a slidable detent which is spring-loaded to a position in which its nose projects inwardly into the housing 9 in the path of the flange 22. As the key is turned from the "off" position to the "auxiliary" position the web 6 of the slide engages an arcuate outer periphery of the cam 3 and hence the slide does not move towards the locking position. As the auxiliary position is reached the tongue 23 of the member 18 engages the abutment 25 which prevents further turning of the key, and hence the portion 15 of the lock structure, until the lock structure 13 has been depressed so that the tongue 23 clears the end of the abutment 25. Further rotation of the inner portion 15 to the lock position causes the web 6 to engage a cutaway section 10 of the cam 3 to allow the spring 2 to move the slide 1 to the locking position. The portion 15 can be turned from the "lock" position to the "off" and "ignition" positions without depressing the structure 13, since the end of the pawl 25 has an inclined face and it slides back against its biasing spring 29. If the lock structure 13 is depressed before the "off" position is reached the member 27 projecting from the inner end of an outer lock portion 14 of the lock structure is halted by an oppositely facing projection 28 at the periphery of the cam 3 and prevents rotation of the inner portion 15 of the lock structure to the "off" position. The cam has a spring-loaded detent projecting from its periphery which in the "off" position engages a recess 31 in the housing 9 to index the "off" position.