Patent GB-763609-A (GB)
Title: Electrically remote controlled locks
Inventor: GRIMALDI LEONARD ELI
IPC: E05B47/06
Filed: 1953-10-20
Abstract: 763,609. Door locks. STERDY TELEPHONES, Ltd. Jan. 20, 1955 [Oct. 20, 1953], No. 28986/53. Class 44. A door lock has a spring-loaded plunger 3 with rounded or double bevelled end 4 engaging the door frame or door lock, the plunger being held in locking position by an abutment 8 moved into and withdrawn from the path of the plunger upon successive excitations of an electromagnet 11, momentary excitation of the electromagnet causing full retraction or projection of its armature 14, leaving the abutment subject to a force sufficient to withdraw it from the path of the plunger at once or as soon as external pressure is removed from the door. As shown in Fig. 1, the armature 14 holds the abutment in its locking position when the armature is extended and when the armature is withdrawn the abutment is moved out of the path of the plunger 3 either by gravity or by a coiled spring 15. The electromagnet has windings 12 and 13, one to extend the armature and the other to withdraw it. A stop 17 limits the movement of the abutment to its locking position and a shoulder 19 on the abutment limits the movement of the armature 14. The plunger 3 has a threaded stem on which there is an adjusting knob 16 by which the extent of projection of the end 4 of the plunger can be adjusted. In a modification to reduce the overall length of the fastening the abutment can be operated by the electromagnet through a pivoted cam. In a further modification the electromagnet is mounted vertically instead of horizontally, as shown, and the abutment has two arms and the armature of the electromagnet bears on one arm to pivot the other arm out of the path of the plunger. In another construction, Fig. 4, the abutment is a disc 38 having a plurality of notches 42 into which the end 41 of the plunger can move when the plunger is withdrawn. A ratchet-wheel 43 having twice as many teeth as there are notches is connected to the disc 38 and the ratchet wheel and hence the disc is rotated by a pivoted pawl 44 carried by the armature 45 of the electromagnet. The ratchet wheel is held against return movement by a spring detent 46 and since there are twice as many teeth as there are notches in the disc the movement of the plunger is obstructed at every alternate tooth when the periphery of the disc between the notches is presented to the end of the plunger. The electromagnet has a single winding which acts to move the armature 45 into the electromagnet and it is returned to its extended position by a spring; hence alternate excitations of the electromagnet look and unlock the plunger. The disc 38 may be connected to the ratchet wheel by a spring so that if pressure is being exerted on the door so that the frictional engagement of the plunger with the disc prevents the movement of the disc the ratchet wheel can still turn with the disc following it when the pressure on the door is released. In a modification of this construction the abutment is a vertically slidable block, supported against gravity by a disc having a wavy edge so that for alternate excitations of the electromagnet the abutment is lifted and allowed to fall. In each construction a keyhole may be provided adjacent the abutment through which the abutment can be moved by a key in the event of failure of the electromagnet.