Patent GB-1296972-A (GB)
IPC: B60R25/021
Filed: 1968-11-20
Abstract: 1296972 Anti-theft devices LOWE & FLETCHER Ltd 20 Nov 1969 [20 Nov 1968] 54951/68 Heading B7J [Also in Division E2] A locking device comprises a lock body 10, a key-operated lock mechanism which includes a key-receiving member having tumblers movable by means of a key to release the keyreceiving member 27 for movement relative to the body, and a bolt member 17 movable by the key-operated lock mechanism relatively to the body between a locking position and a releasing position, in the former of which positions (when the device is in use) the bolt member is adapted to co-operate with a control member which is required to be locked against movement and in the latter of which positions it is released from said control member to allow same to move, the device comprising first and second units, the first unit including the key-receiving member and the second unit including the lock body, the bolt member and a retaining element 21 for releasably holding the bolt member in its releasing position prior to assembly of the first unit with the second unit, the second unit being adapted to receive the first unit so that the first unit can be assembled with the second unit subsequent to assembly of the components of the second unit with one another, and means being provided for securing the units in assembled relation. In the construction shown the retaining element is mounted in a transverse groove 22 formed in the bolt member 17, a spring 23 urging the retaining element to the right as seen in Fig; 3, the bolt member is mounted in a guideway in the body and in which is a longitudinally extending spline 24 and when the bolt member is in its releasing position the end portion of the retaining element lies above the upper end of the spline 24 and hence the return  of the bolt member to its locking position under the influence of its biasing springs 19 is positively prevented. The bolt member can be  held in this way by the retaining element before the cylinder lock mechanism is assembled to the remainder of the locking device. The cylinder lock mechanism is disposed in a cylindrical bore 25 in the lock body and comprises a cylindrical housing 26 the key receiving member which is in the form of a barrel 27, plate tumblers and tumbler biasing springs, the tumblers normally engaging grooves 28 in the housing to prevent rotation of the barrel, the barrel being rotatable when the tumblers are withdrawn into the barrel by a suitable key. The means securing the units together is either a hardened pin (not shown) penetrating the body and the housing or a spring loaded ele-  ment inaccessable from the exterior of the body. The barrel is formed with an integral extension 30 which includes a collar 31 between which and a part of the housing a compression spring 34 is disposed which urges the barrel relative to the housing in a direction inwardly of the lock body. The collar is provided with a radially projecting peg 32 which co-operates with an end face 33 of the housing to control the axial positions of the barrel. The extension 30 carries a spindle 35 which is fixed to it by a pin 36 and which has a portion 37 of non-circular shape which is engaged with a correspondingly shaped socket in an actuating element 38. The actuating element has a cylindrical portion journalled in a bearing opening 39 in the body and a cam 40 which co-operates with a ledge 41 formed at the rearward side of the bolt member 17 so that rotation of the barrel in one direction withdraws the bolt and rotation in the other direction releases the bolt so that it can be returned to its locking position by the springs 19 which as shown are disposed one on each side of the spindle and are trapped between the bolt member and the housing. The spindle 35 also carries a second actuating element 42 which is in the form of a plate and which is urged in a rearward direction by a spring 43; the element 42 has a finger 44 which co-operates with the tooth 45 of the element 21 to move the latter from its active to its inactive position; the body also has a chamber 13 to receive a switch unit which incorporates contacts for controlling the supply of current to the ignition circuits of the vehicle and further contacts for controlling the supply of current to the starter motor, the switch being operated by an end portion 49 of the spindle. The barrel of the lock mechanism and the parts connected to it can take up four different positions which in the clockwise direction from the front of the cylinder lock mechanism are a locking position in which the bolt member prevents movement of the steering shaft of the vehicle, an ignition-off position, an ignition-on position and a starting position; in the last three positions the bolt member is in its releasing position. Rotation of the barrel by the key from the locking position to the ignition-off position causes the cam 40 to engage the ledge 41 to raise the bolt member 17 to the releasing position; the movement of the bolt member raises the retaining element 21 above the end face of the spline 24 and retaining element is shot to the right by spring 23 and the bolt member is thus held in the releasing position: in this ignition-cff position the second actuating element 42 has been moved by the spring 43 rearwardly until its movement is stopped by the ends of flaps 46 provided by the spindle, in this position an arcuate part of the periphery of the drum 142 lies beneath the tooth 45 of the retaining element 21. Further rotation in the clockwise direction moves the switch to the ignition-on and starting positions respectively without moving the bolt member, when the barrel is rotated by the key in the anticlockwise direction from the ignition-on position to the ignition-off position, a stop element 41 formed on the bolt member engages the cam 40 to limit rotation of the barrel and during the movement the finger 44 of the second actuating element engages the tooth 45 of the retaining element and withdraws the retaining element to the left to its inactive position. However the bolt member cannot return to its locking position since the arcuate portion of the periphery of the element 42 underlies the tooth 45. For all positions of rotation of the barrel from the starting position to just before the ignition off position, axial movement of the barrel towards the forward end of the body is prevented by the peg 32 being in engagement with the end face 33 of the housing; in the ignition-off position however the user, by pulling upon the key against the spring loading of the barrel, can pull the barrel forwardly and this withdraws the element 42 from beneath the tooth 45 of the retaining element so that the bolt member is freed to move into its locking position; the stop element 47 then no longer obstructs further anticlockwise rotation of the barrel and the barrel can then be rotated to the locking position in which the key can be withdrawn. An accessories position can be provided between the ignition-off and the ignition-on position in which further contacts incorporated in the switch unit are closed to bring accessories of the vehicle into operation under the control of further switches individual thereto as required.