a mechanical lock of the type where a rod is normally locked for axial movement through a lock housing by a spring tightly wound about the rod and axially fixed to the housing , the rod being released by partially unwinding the spring . the lock housing is configured to reduce the number of parts in the lock and is easily adjustable during assembly to eliminate axial free play of the locking spring . the lock is assembled without welding of the components to permit use of dissimilar materials in the lock housing selected for strength and weight characteristics and plated or painted components .