GB747203A - Improvements in or relating to electric circuit control timing apparatus - Google Patents

Abstract

747,203. Time switches. I.B.M. UNITED KINGDOM, Ltd. Nov. 11, 1954 [Nov. 11, 1953], No. 31244/53. Class 38(5) A timing device comprises two rotatable drums 3, 4 and a plurality of switches, one drum 3 being driven by timed electric impulses from an external source and once in every revolution giving an electric impulse to drive the other drum 4, each drum carrying detachable tappets 39 in selected positions and each switch having two actuating members 33 co-operating respectively with said tappets so that the switch is only operated upon simultaneous engagement of its actuating members by a tappet of each drum. Drum 3 which rotates once every three hours is driven through a gear train from a ratchet wheel 13, the operating pawl 15 of which is carried by a lever 16 also carrying an armature that is attracted once a minute against a spring 19 by a pulsed electromagnet 21. A tappet on a part 44 of drum 3 closes contacts 32 (Fig. 1) once a revolution so as to energize an electromagnet 30 driving a ratchet wheel 23 on a shaft 2 carrying the drum 4 which rotates once a week. Each drum comprises an arcuate strip 46 engaging grooves in end plates 45 and formed with slots 38 in which the tappets 39 may be selectively arranged. The switches are arranged in a row between the drums and each switch has a pivoted actuating member 33 having rollers 37 acting on contact springs 36 which are connected in: series by a wire 42 so that each switch is closed only when both members 33 are actuated. The tappets are formed as U-shaped clips, each leg of which is weakened so that it may be broken off if not required. Each tappet may actuate two adjacent members 33. The device may be connected to the system of Specification 352,207 [Group XVIII], so as to provide automatic time correction.