GB1324349A - Magnetic locking mechanism - Google Patents

Abstract

1324349 Magnetic locks H O BOEHME Inc 21 Jan 1972 [21 May 1971] 3069/72 Heading E2A A magnetic lock for example for a gate has a slidable core member 32 having holes 34 in which are located magnetic tumblers 36, and a keeper plate 20 having holes 60, 62 of different sizes into which the tumblers protrude such that when a pass card 82 having magnetised spots coinciding only with the tumblers 36 located in the smaller holes 60 is inserted in a slot 78 provided between bottom plate 22 and guide rails at these tumblers are repelled allowing the core 32 to move by engagement of the pass card with a core flange 85 to an intermediate position and when a pass card having magnetised spots coinciding with all the tumblers is inserted the core 32 is allowed to move to its fully retracted position. The two positions correspond to, for example, night and day-night use; the lock may only be opened when the corresponding pass card is inserted during each period. Two microswitches 52, 54 are provided to open the gate and are actuated by a post 46 mounted on cover 32 which engage leaf spring operator arms 56, 58 of the switches. A night pass card opens lock 10 only if a control switch 102 is open whereas a day-night pass card opens lock whether the switch is open or closed. If it is required to permit access only to persons holding night pass cards switch 102 is closed and when the night pass card is inserted the core 32 moves to its intermediate position in which only switch 52 is actuated by post 46 Insertion of a day-night pass card causes core 32 to move. its fully retracted position in which switch 54 is closed and the lock is allowed to open. Switch 102 may be manually operable (e.g. by a key) or automatically (e.g. by a time clock). The lock is programmed by a card 68 provided with selected magnetised spots to attract one or more of the tumblers out of their associated holes 60, 62 the card 68 being held in position by a bowed end portion 73 in a retaining plate 16. A -tamper prevention pin 44 is provided for preventing unauthorised unlocking of the lock 10 and is located in a stepped hole 42 of the core 32. The pin has an enlarged flange 44a such that if an attempt is made to open the lock by a sharp blow which would cause the magnetic tumbler pins to jump upwardly out of the holes 60, 62 in the keeper plate 20 pin 44 also moves upwardly so that the upper end thereof extends in the rear portion of a slot 48 located in plate 16 thereby preventing significant movement of core 32. The tamper pin is non magnetic, preferably of bronze.