Lock device for chain driven vehicles

A locking device of the type adapted to engage the links of a drive chain of a vehicle, such as a bicycle, motorcycle, moped of the like, comprising a lock mechanism having a hollow housing mounting a key actuated tumbler means having a locking arm means adapted to be moved between a locked and an unlocked position, said housing having a pair of oppositely disposed openings adapted to provide ingress and egress into the housing, a locking plate member including a flat base plate portion and an integral downwardly depending side plate portion defining an L-shaped configuration in side elevation providing a protective outer skirt, at least one elongated locking pin element made integral with and extending downwardly from said base plate portion and parallel to said side plate portion and spaced laterally from said side plate portion, said locking pin element having a recessed slot adapted to receive therein the confronting end portion of said locking arm of said lock mechanism.