GB1460660A - Counters or timers - Google Patents

Abstract

1460660 Time switches GULF & WESTERN INDUSTRIES Inc 24 Dec 1974 [25 Feb 1974] 55781/74 Heading H1N [Also in Division G4] A counter, which may be driven by a synchronous motor to form a timer and which is presettable to a value from which it counts to zero and then issues a signal, comprises, for each decade, a first number wheel 20 which can be manually indexed to display the preset valve and a second wheel assembly comprising a gear 50 meshed with gear teeth 42 of the wheel 20 and a second number wheel 30 which is biased to a fixed position relative to the gear 50 but driven away from that position during counting. In use the preset valve is set on wheels 20 by a push-button 10-actuated pawl 300 acting on a ratchet fixed to the wheel 20; when a start signal is given a solenoid 150 is energized to disconnect the drive 60 and the transfer wheels 172 from the second number wheels 30 freeing the latter; diametrically magnetized permanent magnet inserts (220, 222, 260, 262) (Figs. 7, 8, not shown) on the gear 50 and wheel 30 respectively attract and cause the second number wheels to move into alignment with gears 50 and thus display the same value as first number wheels 20. At the end of the start signal the drives are reengaged and wheels 30 then count down to zero; when all the wheels 30 are simultaneously at zero a feeler 120 having a plurality of sensing fingers 122 drops into recesses in cam surfaces 140 on the second number wheels 30 and a linkage operates a microswitch 114; if the wheels 30 continue to count beyond zero the fingers 122 are cammed axially out of the recesses and switch 114 remains operated; when the solenoid 150 is again energized to start a new cycle the feeler 120 is lifted away from the wheels as the drive is disengaged and a second switch 90 is actuated; switch 114 is held closed by an arm 100 until the solenoid is de-energized.