Improvements in or relating to traffic control systems

Abstract

Abstract 442,555. Road signals for controlling traffic. SIEMENS & HALSKE AKT.-GES., Wernerwerk, Siemensstadt, Berlin. Aug. 17, 1934, No. 23806. Convention date, Aug. 17, 1933. [Class 118 (ii)] [See also Group XXXIX] In a road-traffic control system for a number of intersections, the control apparatus for all the signal units is installed at a central station from which impulses are transmitted to the various lamp units when the signals thereat are to be changed. The apparatus of any unit may be selected from a remote main station and the timing of the signals at that unit altered or a group of units, or the whole of the units in the system, may be selected and altered simultaneously. When a signal unit has been selected, indicator lamps at the main station pulse in synchronism with the lamps at the selected station. Pad control may be provided on side roads, but is effective only when the side road may have right of way as defined by the central station equipment and the time of such right of way is varied in accordance with the number of vehicles waiting. Green wave connection between a number of units in a thoroughfare may be provided and telephony may take place between any unit and the sub-station or the main station and between sub and main stations. Manual control of the individual units is also provided. General arrangement. The system described contemplates a number of groups of units VSt, Fig. 1, controlled through sub-stations UZ from a main control office HZ. The main station is connected to each sub-station by three pairs of wires 3, 4 ; 5, 6 ; and 7, 8 which are used respectively for selection and control, for telephony and supervisory signalling and for telephone signalling and alteration of group timing respectively. When a unit is to be selected, its number is dialled over line 3, 4 and switch Wuz is set to the required position so that a control unit such as Vsts1 connected with remote signal unit Vst1 is selected. Lamps shown above Vsts1 normally pulse in synchronism with lamps Vst1 and when selection has been made lamps at HZ (shown in Fig. 4) also light in synchronism, the signalling pulses being transmitted over lines 5, 6. If the signal sequence is to be altered, one of a number of keys at HZ is operated which operates one or more of a number of relays at Vsts1 and these determine which of the pulses generated by Zsch and transmitted to the apparatus through switch Sts and distributing frame Rvt shall be passed to operate the signal lamps at Vst1. Road pads Bschw may be provided on one of the roads at the crossing and these when operated, transmit pulses over a line 9, 10 to the main station so that right of way may be transferred at the appropriate time to the calling route. By setting switch Wuz to one of its positions all the units Vsts associated with a group Grs may be simultaneously controlled whilst a still further position of the switch selects Ssch so that all the units Vsts in all the group Grs can be simultaneously set. If a telephone call or a fault occurs, the finder switch Fspw hunts for the calling line and the fault lamp DrL or the telephone signal TL is operated. Operation of signal lamps. When the unit (Fig. 11) is to be put in operation, contacts HS1 and HS2 are closed so that when steady current flows over lines 1, 2, relays EA, EB are operated to light the red lamp rt1 on the main street and the caution lamp ge2 on the cross street. When steady current on conductor 1 is increased, the marginal relay AL pulls up and the signals change to the green "GO" lamp gr1 on the main street and the red " STOP " lamp rt2 on the side road. The lamp Sgn1 is also lit and indicates the correct point in the cycle for cutting over from manual to automatic control if the system has been working manually. At the termination of the " GO " period, current on conductor 2 is increased so that relay BL operates to alter the main road signal to the caution lamp ge1. When the caution period is over, relay AL is de-energized and the signals change to red lamp rt1 on the main road and the green lamp gn2 on the cross street. The release of relay BL at the end of this period restores the apparatus to its normal condition and the cycle is repeated. Selection of traffic signal stations. To select a traffic signal station, the number of the station is dialled, the dial operating off-normal contacts nsa (Fig. 4) and dial contacts nsl. The relay I, Fig. 5, energizes and the slow relays C, R and CH operate in turn, the relay I repeating the digit to the vertical magnet H of a two-motion selector so that wipers a1-e1 are raised. When the impulse train terminates, off-normal contact k1 closes, relay C falls away and relay V pulls up. The second digit of the required station number is now dialled and relay I repeats the impulses to the rotary magnet D and the rotary off-normal contact w closes. Relay C releases and relay P is energized connecting the control line 3, 4 to the relay group AH, AF, ZA, BH, BF, ZB. Relays ZA and ZB pull up and the other relays can be selectively operated, as will be described later, by keys I-VII at the main station. Control switch. The control switch, shown in Fig. 8, is provided with two turning mechanisms (only one of which Zsch is shown), each comprising a motor Mo which closes contact mok at definite intervals. The time switch to be used is determined by keys EI, EII, (Fig. 4), which control relay RU, Fig. 8, to one of its two operating positions. In one position, contacts ru1, ru2 only are closed so that the time mechanism connected over 11, 12 is used ; in the other, all contacts are made so that contacts ru3, ru4 are effective and the time mechanism Zsch is brought into action. One of the relays F, H is energized so that relay An pulls up and the time mechanism motor Mo is started. Impulses generated by mok are repeated by relay IS to magnet SD and wiper sta is stepped over its contacts. In its final position relay RW energizes over sta and relay An is released so that if both relays H and F have fallen away the switch stops. In its normal position relay W is energized over wiper std, relay FS having pulled up when RW energized, and relay RW is unlocked. The stepping switch can also be released by the energization of relay AbT, Fig. 6, which energizes relay RW and enables magnet SD to step home over wiper std the relays FS and GS interacting to form an interrupter. The wiper sta connects positive to contacts 0-60, Fig. 7, in turn so that relays A and B are energized and released to control the signal lamp relays AL, BL. If no road pads are provided, the terminals 61-68 are connected as shown in Fig. 7 and the times in the cycle at which relays A and B are operated and released is determined by the condition of relays H, U and V, Fig. 6, through marginal relays AH, AF, BH, BF, either directly or where groups of units are being set together, through HG, FG, UG, VG, so that the distribution of the signals over a cycle can be controlled from the main station. The lamps shown at the foot of Fig. 7 light as relays A, B are operated and so indicate the cycle of the remote lamps whilst when a station has been selected, the lamps shown in Fig. 4 are also operated by pulses over lines 5, 6. Disconnection of stations. If the key VII, Fig. 4, is operated, relays BH, BF operate together and relay Ab is energized. Energized relays of the group H, F, U, V are released and relay S falls away to open the impulsing circuits 1, 2 to the controlled station. Relays EA, EB release and the signal lamps are extinguished. If a group of stations is to be disconnected, the switch is set to the group positions so that relay AbT is energized either directly by BH, BF or, if a number of groups are being disconnected together, through AbG. Relay AbT opens the holding circuits for energized relays of the group H, F, U, V so that the station is disconnected and also homes and releases the switch Sts, Fig. 8, as described above. Restoration of main station switch. When the key R, Fig. 4, is operated, relays ZA and ZB fall away so that relay RA and magnet D are connected in series. Relay RA shorts itself out to allow D to operate so that the switch is moved to its eleventh rotary position where it drops to its lowest level and is restored to normal by a spring. Pad operation. When pads are provided in the side roads, the terminals 61-68, Fig. 7, are connected as shown in Fig. 12. If no vehicles are waiting, right of way remains with the main road, but when the road pads BschwI or BschwII are energized, magnets BO, BB are energized to step wipers bo, bb. Relay O releases. When the wiper sta, Fig. 8, reaches contact 30, Fig. 7, relay BH, Fig. 12, is energized and, as relay O is back, relay CB releases and relay B, Fig. 7, energizes to transfer right of way to the side street. When relay A falls away at the end of the caution period, relay QB pulls up so that the slow interrupter LU is connected up. This may be a relay interrupter with a 5 second pulse and so allows five seconds for each waiting vehicle. At each pulse of LU the stepping magnet SU steps wiper su and when it reaches a contact marked by bo (which is assumed to be reached before bb) relay LB energizes so that wipers bo and su are stepped together. When the contact marked by bb is reached, relay RB is energized and then relay O pulls up. Relay IS, Fig. 8, is pulsed by contact mok and when the next pulse is received, relay CB is re-energized and locks. Relay Hi pulls up, relay AB energizes and relay A operates to remove right of way from the side road. Relays LB, RB and O remain locked up until another vehicle passes one of the pads when wiper bo or bb is moved, relay LB or RB falls away and O, AB and Hi release. A call is thus registered so that, when switch sta is in a position to allow the transfer, right of way is again given to the side road. If the main street signal is co-operating with other signals to provide a green-wave through a thoro

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