Patent GB-436602-A (GB)
Title: Improvements relating to street traffic signalling systems
IPC: G08G1/08
Filed: 1934-05-29
Abstract: 436,602. Road signals for controlling traffic. SIEMENS BROS. & CO., Ltd., Caxton House, Tothill Street, and TYACK, F. G., 21, King William Street, Greenwich, both in London. May 29, 1934, No. 16025. [Class 118 (ii)] In a pad controlled system for a crossing at which a considerable bulk of traffic turns across the opposing traffic stream, the right of way is taken from the road in two stages, the first stage stopping traffic in one direction only to allow traffic moving in the opposite direction to turn across, the controlling apparatus for the extension of the right of way period being controlled only by the pad in the route of the traffic first stopped until this traffic is stopped and then being controlled by the pad in the opposing lane. The facility may be provided by a detachable control unit which can be jacked into a unit giving normal pad-operated service. As shown in Fig. 2, a considerable bulk of traffic from road W wishes to turn across the westbound traffic into road S. Consequently if right of way is to be taken from the E, W route, when a gap occurs in the traffic moving westward (or the maximum period expires), the signal EG is replaced first by the amber EA and then the red ER. Traffic from W is not, however, arrested and this can now turn into S. When a gap occurs in the traffic operating pad w, or the maximum period for this traffic has elapsed, the lamp WG is extinguished and lamps WA, NA and SA are lit, these lamps being replaced by lamps WR, NG and SG when the amber period has expired. The apparatus for providing the features of this invention is shown below the broken line in Fig. 1 and is marked COS, that marked MRS providing normal pad-controlled facilities. The jacks 1-20 are arranged so that when the apparatus COS is not provided the connections shown dotted between 1, 2, 3 ; 4 and 5; 6 and 7; 11 and 12; 13 and 14; 15 and 16 ; 17 and 18; and 19 and 20 are made. The apparatus MRS functions as follows: with right of way on route EW, only relay BR is energized. If a demand is received on route NS, one of the pads n, s is operated so that relay DE is energized and locks, connecting up the timer S, ST, QNB. Each vehicle passing along the EW route operates either pad e or w so that relay RW responds and adds a charge, depending on the speed of the vehicle, to condenser QNB but when a break occurs in the traffic flow lamp S breaks down and relay ST operates, energizing relay STA. Relays RC, RA and AM pull up and relay DE falls away. The connections from the pads to the relays RW and DE are changed over, relays CO and MG pull up, green lamp, EG and WG are extinguished and all the amber lamps NA, SA, EA and WA are lit. When ST releases, relay STA falls away and LC energizes. The amber timer becomes effective when CO and MG are energized so that lamp A strikes and relay AT is energized followed by ATA. The condenser QNA is re-charged over AT and ata3 so that relays AT and ATA fall away almost at once. Relays RA and AM fall away followed by slow release relay CO and relay AR is energized giving the right of way to the N.S. route. Relay CG is energized and the amber timer is again effective to time the minimum green period. When this period has expired relays AT and ATA again energize and release, and relay MG falls away so that the speed timer S, ST is again connected up and is effective when the demand relay is next energized. When this happens relays ST and STA are operated, relays RC and LC release, relays RA and AM are operated and an amber period is timed after which the circuits change to bring right of way back to the E.W. route. If the traffic on a route is fairly continuous the maximum timer M, MT, QNC, connected up when the demand relay DE operates, becomes effective and relays MT and MTA operate. The condenser QNB is discharged rapidly so that relay ST is energized and the right of way is taken forcibly from the route holding it. Under these conditions resistance R6 provides an increased amber period. When turning traffic is to be catered for, the apparatus COS is jacked in. With right of way on the E.W. route, relay BR alone in MRS is energized so that relay EC is operated and pad e alone controls the relay RW. When a demand is received from route NS, relay DE energizes and locks so that the speed timer is connected up. When relay ST energizes, relays ET, ER, EGA, EM and ESA are operated, and RA pulls up and locks. The green lamp EG is extinguished, the amber lamp EA is lit, the pad w is connected to RW and pad e to relay EDS. The amber timer is connected up over esa4. When relay ET releases, relay ESB pulls up. When the amber timer flashes, relays RA, CO and EM release so that the amber lamp EA is replaced by the red lamp ER. The amber timer now times a minimum green period and then the speed timer is again connected up, the period extending control now being on pad w. Traffic can now turn unimpeded into road S. When lamp'S again flashes either on a break in the eastbound traffic or on the operation of the maximum timer, relays ST and STA energize, relay RC is operated and RA pulls up. Relay LC pulls up when ST releases so that relays EC and ESA release. Relay ESB falls away slowly to allow EDS, if it is operated, to register a new demand on DE. Relay AM operates and locks, lighting lamps NA, SA and WA and extinguishing lamp WG. The amber period is timed and relays AT and ATA pull up so that relays RA, AM, ER, EGA and BR fall away and relays AR and CG operate, extinguishing the amber lamps and the red lamps NR, SR and lighting lamps NG, SG and WR. Pads e and ware now connected to relay DE in parallel so that a demand in either road initiates the return of right of way. When the right of way is being returned relays RA and AM are again operated and LC and RC are released, relay LC falling away slowly. When LC finally falls away relay EC only in the apparatus COS is energized, the amber period is timed by the amber timer and right of way is restored to the E.W. route. If the switch SW is opened, the relay EC is not operated when LC falls away and then apparatus COS becomes ineffective, the circuits for the normal operation of MRS being established over normal contacts of relays in COS. Specification 418,070 is referred to.