Patent GB-1289822-A (GB)
IPC: B60R25/021
Filed: 1968-08-29
Abstract: 1289822 Anti-theft devices WILMOTBREEDEN Ltd 25 Nov 1969 . [29 Aug 1968] 41260/68 Heading B7J [Also in Divisions E1-E2] A cam-and-slide mechanism for a vehicle anti-theft device has a housing 1 with an operating shaft rotatable therein, a locking slide 2 movable transversely of the shaft between a locking position and a retracted position and a rotary cam 4 on the shaft for moving the slide, the housing having mountings for receiving a key-operated lock structure 9 to engage and drive the shaft at one end portion of the shaft and a switch mechanism to engage and be driven by the shaft at the other end portion of the shaft, the shaft being rotatable through successive angles from a locking position first to retract the slide and then to take up positions usable for switching purposes, means being provided which prevent the shaft being turned back directly from the switching positions to the locking position and which comprise a detent 14 rotatable with the shaft and axially depressible, the arrangement being such that, as the shaft is turned from the switching positions towards the locking position, the detent engages an abutment 17 in fixed relation to the housing, which abutment can be cleared only by axial depression of the detent, while in the event of such axial depression before the first-mentioned abutment is reached the detent engages another fixed abutment 18 which can be cleared only when the detent is not depressed, whereby, in use with the key-operated lock structure depressible to depress the detent, turning of the key to locking position of the shaft requires a depressing movement of the key at a predetermined angular position. In the construction shown the slide 2 is biased by a spring 3 toward the locking position, the cam moving the slide from the locking position to the releasing position by engaging a projecting web 7 which bridges a slot 6 in the slide and on which the cam acts. The web 7 is separate as shown from the main portion of the slide but is attached to the latter in the assembled condition. In a modification, Fig. 3, a pawl 20 is provided which is pivotally mounted about an axis parallel to the cam shaft 5 on the end of the web 7 of the slide 2; the pawl is quadrant shaped and is spring loaded in the direction of the arrow P to a position in which one straight edge face 22 is aligned with the slide axis 2 and radial to the shaft 5; in this position an apex 23 engages the periphery of an auxiliary cam lobe 24 positioned alongside the cam 4 and the engagement holds the slide in the releasing position even though it has been released by the cam 4; just before the shaft 5 reaches the locking position the auxiliary lobe 24 leaves the straight edge face 22 to free the slide 2 which is then moved to the locking position by the spring 3; when turning in the opposite direction the pawl 20 is displaced by the lobe 24 which moves with the cam 4. An alternative construction is also described which holds the slide in the releasing position until just before the locking position is reached. In this construction an auxiliary cam is provided which is driven by the cam 4 with a degree of lost motion and the web 7 of the slide has a projection which can be engaged by the auxiliary cam to hold the slide in the releasing position until just before the locking position is reached.