Patent GB-651987-A (GB)
Title: Improvements in and relating to electric combination switch devices
IPC: G07C9/00
Filed: 1948-03-04
Abstract: 651,987. Electrically-operated locks. JENKINS G. M. O. March 4, 1948, No. 6764. '[Class 44] [Also in Groups XXXVII and XXXVIII] In a combination switch device of the kind comprising a selector 11 which is moved over contact studs 10 to a selected position 10a, whereupon the pressing of a switch 14 operates an electromagnet 15 to remove its armature 15a from a pawl 16 on a lock 17, and wherein if the selector contacts any other stud 10, on pressing the switch 14 an alarm 12 is actuated, the alarm is operated by a relay also energized by the switch 14. Instead of individual studs, a metal ring having a single insulated stud may be used. The ring is mounted on an insulating base provided with locating projections which, when assembled as a unit, engage numbered apertures on a disc secured to a mounting Figs. 2a. 2b, 3 (not shown). In one embodiment, Fig. 4, a series of switches, having rings 40a-40d and insulating studs 43a-43d in different circumferential positions, are connected together to shunt the electromagnet 41. When the selectors 42a-42d contact the studs and the switch 45 is operated current flows through a low resistance winding 46a of a relay 46, shunted by a metal lamp-filament 47, to the electromagnet. If any selector is on its ring when the switch is pressed the current flows through the selector shorting the electromagnet, and energizes the relay winding 46a to close its contacts 46c thereby energizing the relay hold-in winding 46b and operating the alarm 48 independently of the switch 45. A secret masterswitch 49 is provided to cut-off the supply 44 and allow the relay to be reset. In a modification, Fig. 6, two concentric rings 51, 52 are employed, the inner ring 52 being connected to a solenoid 55 surrounding the spindle of the selector 50 which then has two arms and is biassed against a insulated stop 54 by a spring 53. When the selector is moved over the rings, the solenoid -is energized to pull theselector against them and prevent it being returned by the spring. A cancelling switch 57 operated preferably by the door handle 62 is provided. In a further modification, Fig. 10 the selector is gravity biassed, Figs. 8, 9 (not shown), and is mounted so as to be movable longitudinally so that it may contact a ring 90 or a selected stud 87a-87d the studs being proud of the base plate in which the ring is embedded. The ring is permanently connected to the alarm circuit 102 containing a secret master switch 104 and a door switch 107. When the connector is pushed to contact the stud 87a and the interlock switch 105 is opened before or preferably by the movement of the selector the relay 100 is energized closing its open contacts 100a, 100b, thereby holding itself in circuit. When in the correct order the stud 87b is contacted the relay 101 is energized thereby opening the contacts 101a, 101b, and closing its hold-in circuit. When the selector contacts stud 87c it shorts out relay 100 which allows its contacts to be reset. On the selector contacting stud 87d, the interlock 105 is returned to its original position and current passes from the source through the door switch, the interlock, the electromagnet 106 to the select,or. The electromagnet armature then releases the lock, the selector having returned to its initial position under gravity.