GB994418A - Improvements in centrally controlled traffic signal arrangements - Google Patents

Abstract

994,418. Transistor circuits. SIEMENS & HALSKE A.G. Aug. 25, 1961 [Aug. 26, 1960], No. 30758/61. Addition to 994,417. Heading H3T. [Also in Division G4] In a centrally controlled traffic signalling system having programming units at both the central station and the individual intersections, the durations of some of the signal phases are controlled by pulse counting circuits, the count being initiated by control signals from the central station. As described a pulse unit Tv E , Tv Z , Fig. 1, feeds pulses, Fig. 2, on lines 0-9, 00-90 to a cross wire unit P providing outputs at predetermined times (0 sec. and 49 sees.) on wires 1, 2 and 3, 4 respectively. Assume initally relay B is actuated closing contact b1 to give a red signal. At time 0 sec. pulses occur on both lines 1 and 2 and transistor T1 conducts switching on transfluxor Tf1 allowing the 25 kc./s. generator G1 to pulse transistor T3 and actuate relay A giving a red and yellow indication. Contact a1 changes over producing a pulse which sets core K1 and switches on transformer Tf2 feeding 50 c./s. pulses to the counter chain Ft1 . . . Ft3 comprising two divide by five stages and one divide by six stage. After 150 pulses (i.e. 3 seconds) transistor T9 cuts off transfluxor Tf2 and samples core K1 to switch transistor T4 on briefly and switch off transfluxor Tf3. Transistor T6 is then cut off and relay B releases giving a green signal. At time 49 sees., pulses are fed to lines 3, 4 operating transistor T2 and switching off transfluxor Tf1 thus releasing relay A and giving a yellow signal. The release of relay A initiates a pulse from contact a1 to set core K2 and switch on transfluxor Tf2 starting another counting period so that after 3 seconds, transistor T9 operates again, sampling core K2 to switch on transistor T5. Transfluxor Tf3 is again actuated and transistor T6 is pulsed at 25 kc./s. from generator G2 to actuate relay B and give a red signal again. Fig. 4 (not shown) gives an alternative form of counter in which the yellow and red + yellow phases may be of different duration. In this counter, 1 sec. pulses are stepped along a three-stage counting chain, outputs being obtainable after 1, 2 or 3 seconds. An alternative cycle spit may be obtained by operating switches p1, p1<SP>1</SP>, p2, p2<SP>1</SP> to connect cross-wire board P<SP>1</SP>.