Patent GB-1288749-A (GB)
IPC: B60R25/021
Filed: 1968-12-06
Abstract: 1288749 Anti-theft devices JOSEPH LUCAS (INDUSTRIES) Ltd 20 Nov 1969 [6 Dec 1968] 58028/68 Heading B7J [Also in Division E2] A combined ignition switch and steering column lock assembly for a road vehicle, comprises the combination of a key-operated mechanism, an ignition switch, and a bolt mechanism 11, wherein angular movement of a key inserted into the key-operated mechanism moves a part of the ignition switch to operate the switch and also rotates a cam 28 to withdraw the latch bolt 13 of the bolt mechanism against the action of resilient means 16 urging the latch bolt to an operative position wherein in use the latch bolt engages the rotatable part of the steering column of the vehicle, the rotatable cam acting on the latch bolt through the intermediary of a lever 29, one end of the lever being pivotally connected to a part 12 fixed with respect to the latch bolt, the other end of the lever engaging the latch bolt, and the cam acting on the lever intermediate its ends. The key-operated mechanism is a cylinder lock mechanism, the barrel 22 of which includes a metal finger 30 which is moved upwardly into engagement with an arcuate cam track 31 formed integrally with a spigot 21 of the casing which contains the barrel; the finger 30 is moved radially upwardly against the action of a spring 32 and is capable of tilting movement relative to the barrel 22 against the action of the spring 32 although the spring 32 urges the finger to a position wherein it lies at right angles to the axis of the barrel 22. The cam track 31 includes an arcuate ramp surface 33 which terminates in a shoulder 34 and the arrangement is such that in the locking position of the barrel with the operating key inserted into the barrel the finger 29 is engaged with the lowest part of the ramp surface 33; during rotation of the barrel from the locking position to a second position in which the switch prepares an accessories circuit the finger 30 rides up the ramp surface 33 and when the barrel 22 reaches the second position the finger 30 clears the end of the ramp surface 33 and is moved under the action of the spring 32 to engage the shoulder 34 thereby resisting rotation of the barrel from the second position back to the locking position until the key is removed to permit the finger 30 to be withdrawn radially from the cam track 31 by the spring 32, the barrel can take up five positions spaced 30 degrees apart, the third position being a garage position in which the latch bolt is in the releasing position but in which none of the vehicle circuits are completed; the fourth position is the ignition-on position in which the ignition and accessories circuits of the vehicle are completed and the fifth position is the starting position in which the ignition and starting circuits are completed. In the fifth position the lever 29 bears against the shoulder 19 of the bolt and urges it further rearwardly so compressing the springs 16 further. When the key is released in the fifth position the springs move the bolt in the opposite direction until movement is stopped by the flange 17 of the bolt engaging the lever 29 which is itself engaged with a semicircular surface of the cam 28, the movement of the bolt causing rotation of the cam member in view of the engagement of lever 29 with the shoulder 19 to rotate the cam member and hence the barrel back to the fourth position. To lock the steering the barrel is rotated anticlockwise to the second position by the key further rotation being resisted by engagement of the finger 30 with the shoulder 34 of the cam track 31; the operating key is then removed from the barrel so permitting the finger 29 to be retracted by the spring 32 and the barrel is then rotated to the locking position by the spring 16 via the lever 29 and the cam member, the cam member in the second position having a corner portion 28a in engagement with the lever. The spring 16 also shoots the bolt to the locking position. The spigot of the casing is formed with an axially extending groove disposed so that in the locking position the tumblers of the lock mechanism enter the groove to hold the barrel against rotation and to enable the key to be inserted a second groove is provided diametrically opposite the first groove since some of the tumblers are caused to project momentarily from that side of the barrel during the entry of the key; such second groove is extended angularly so that the tumblers can protrude into the groove in the second position when the key is removed; the first groove does not need to be extended angularly. The spigot is also provided with a second pair of grooves in the garage position to enable the key to be removed in such position. In a modification the garage position is omitted.