Abstract: The release mechanism of an electronic timelock employs two bistable electromagnetic actuators to control the "on-guard" and "off-guard" conditions of the lock, each actuator comprising an element of ferro-magnetic material whose magnetic polarity serves as the "memory" of whether the lock is in an on- or off-guard period and which polarity is reversed by single magnetizing pulses through associated coils when each successive on- and off-guard period is programmed to commence.More particularly, when on-guard the coils are pulsed in one direction to magnetize the actuating elements so that they are attracted by specified poles of associated field magnets. In this condition the actuating elements block a beam which is pivotted centrally to a bolt which in turn blocks a bar which is attached to the door's boltwork. When off-guard the coils are pulsed in the opposite direction to reverse the magnetization of the actuating elements so that they are attracted by the other poles of the associated magnets.

Abstract: A security lock for use on sliding doors or gates has a pair of hook bolts which are thrown apart or withdrawn together according to the position of a head on a reciprocable slide. Each bolt has a recess mated to the head with front and rear driving surfaces, this geometry being related to the pivot points of the bolts such that the head drives the bolts positively between their thrown and withdrawn positions with no lost motion and without the need for spring-biasing of the bolts. The slide is deadlocked by a pack of levers, to which a second lever pack is linked, two lever packs being provided so that non-palindromic key-stepping can be employed. If required, the slide can be double-thrown by successive use of two different correct keys, for which different key-hole positions and are provided to cooperate with the lever packs.

Abstract: A combination lock includes an over-center mechanism for moving the fence of the lock between two alternative positions with a snap action, the over-center mechanism comprising a lever arm secured to the fence and turning about a pivot on the bolt assembly and a stressed spring connected at one end to the lever arm and at the other end to a member capable of movement between two positions in relation to the bolt assembly. In one of the two positions the line of action of the spring passes to one side of the pivot of the lever arm and in the other position it passes to the other side of the pivot, so that when the member moves from one position to the other the lever arm is biased to move the fence from one alternative position to the other.

Abstract: A key-operated security lock of the kind including a key-identification mechanism, a thrower turned by the key and a deadbolt, has the deadbolt isolated from the thrower, and includes means operable only by correct identification of the key for connecting the thrower to the deadbolt and for removing a stop preventing retraction of the deadbolt from its extended position. The said means preferably includes a lever pivoted to the deadbolt and formed with a locking projection capable of engagement with a complementary recess in a runner driven along a path parallel with that of the bolt by co-operation with the thrower to connect the thrower to the deadbolt as a result of pivoting of the lever which is prevented by a further member in the form of a pivoted arm which holds the pivoted lever in a position such that its locking projection is clear of its recess until the pivoted arm is allowed to turn by the key-identification mechanism.