Key operated lock for securing a movable portion of a motor vehicle

Claim 1

An anti-theft device for a motor vehicle comprising: (a) a housing, (b) means for securing said housing to a relatively fixed part of the vehicle, (c) a locking bolt movable along a first axis between a locking position where said bolt engages an aperture in a movable portion of the vehicle to be locked and an unlocked position, (d) a driving pin extending from said locking bolt, (e) a driving plate slidable along a second axis transverse to said first axis, said driving plate having a slot receiving said driving pin, which slot includes (i) a first portion inclined to said first axis, (ii) a second portion contiguous with one end of said first portion extending generally transversely of said first axis, and (iii) a third portion contiguous with the other end of said first portion extending parallel to said first axis, (f) a cylinder lock rotatable by means of a key within a bore in the housing for effecting movement of said bolt between locking and unlocking positions, (g) a cam fixed to said cylinder lock so as to be rotatable thereby, said cam being in driving engagement with said driving plate, whereby on rotation of said cylinder lock the cam effects movement of said driving plate which in turn by way of the first portion of the slot causes said locking bolt to be driven into its locking position, and (h) a return spring for urging said driving plate in opposition to its displacement by the cam wherein, due to the second portion of the slot no withdrawal of the locking bolt from its locking position is possible and due to the third portion of the slot movement of said bolt into a fully retracted position without movement of said driving plate for the purpose of assembly of the cylinder is possible.