Patent GB-991733-A (GB)
Title: Electrical control systems for point-to-point transit systems
IPC: B61L23/00
Filed: 1962-11-23
Abstract: 991,733. Automatic vehicle control. STANDARD TELEPHONES & CABLES Ltd. Nov. 23, 1962 [Nov. 29, 1961], No. 44414/62. Heading B7N. A system for automatically controlling the movement of a number of self-propelled driverless vehicles, i.e. vehicles 130, 131, Fig. 2, on one or more elevated loop tracks, i.e. loops 100a, 100b, Fig. 1, joining stations 106-110 in a transportation area, e.g. an airport, comprises a spur track 101 below a main track 100a at each station to allow passengers to embark and disembark at platform 132, passenger controlled means 156 for opening the vehicle door and means 164 for setting the destination which appears in code form on an indication plate external to the vehicle and is read in passing by trackside detectors such as 165<1,> 165<11>, means for determining the position of vehicles on the main loop and for launching the vehicle on to the loop when a space is available, means for controlling the speed of the vehicle during passage to its destination and for operating the relevant points mechanism to divert the vehicle to its destination spur track and for bringing the vehicle to a halt at its destination platform. The track system is divided into two loops 100a (not shown as complete loop) and 100b and the vehicle speed control signals are applied via a three-wire line which runs adjacent each track. The lines include a continuous earth conductor 203, Fig. 7, a segmented A.C. conductor 205 and a segmented D.C. conductor 204 and means are included, e.g. sliding shoes &c. for connecting the lines to each vehicle. Each A.C. segment is connected in the order shown to one of nine lines 1-9 which are connected to a switching arrangement 202, Fig. 21 (not shown), whereby during a first period of time a a signal representing a slow speed (18 m.p.h.) is applied to line 1 and hence to segment 1, a normal speed signal (20 m.p.h.) is applied to line 2 and hence to segment 2, a fast speed signal (22 m.p.h.) to line 3 and hence to segment 3 and no signal, which the vehicle interprets as a braking signal is applied to lines 4-9. During the next period b the slow signal is applied to segment 2, the normal to segment 3, the fast to segment 4 and the braking signal to segments 1, 5-9. The switching rate is such that a vehicle on segment 2 at period a travelling at 20 m.p.h. is always in receipt of a normal speed signal, if the vehicle moves too fast it enters a slow speed segment and if too slow it drops back into a fast speed segment so that it always averages 20 m.p.h. The segment lengths are approximately 10 ft., thus forming 90 ft. " moving " control areas each of which can contain a vehicle. Since the system serves two loops each moving area may be reserved for vehicles for a particular loop, calling the loops black and white and assuming a survey shows that one vehicle in every four is destined for a black loop then one moving area in four is reserved for vehicles destined for the black loop. If the speed on the black loop is required to be greater than that of the white, this can be achieved by adjusting the length of the black segments. The same principle is employed to control the speed of the vehicles as they enter the spur tracks and for bringing them to a halt at the stations. Block control means are provided to prevent rear end collisions, this comprises a relay contact 217 in each lead to an A.C. segment which is controlled via an " OR " circuit 215 which receives input signals from six D.C. segments. If a vehicle is present in one of these segments, a resistor on the vehicle shorts the segment to the earth conductor and the relay contact opens, thus a following vehicle, less than nine segments behind, loses its A.C. control signal and its brakes are applied. A control office for the system includes a control panel with a track layout, a pair of lamps at each segment position, one of which indicates vehicle position and is lit by a circuit from the associated D.C. segment and the other showing the moving control areas. Adjacent the panel track a grooved arrangement is provided which includes a miniature replica of the A.C. segment arrangement, each miniature segment being connected to a track A.C. segment, whereby if a vehicle stalls in the system an operator by means of a tool which slides in the groove can apply a signal to the vehicle which drives it at, e.g., 2 m.p.h. to a point where it can be removed from the system. Means are provided, Figs. 18 and 19 (not shown), for reserving a first available free moving control area so that a vehicle can be launched thereinto, when the vehicle moves into the launch position and its destination is read by the relevant trackside detector. This information determines whether a black or white control area is selected and controls a launch booster arrangement which accelerates the vehicle up the spur track so that it reaches an A.C. segment at the entrance to the main loop at a speed of 20 m.p.h. when the segment is in receipt of a normal speed signal associated with the selected control area. The vehicle speed control, Fig. 22, comprises a number of lines to which the A.C. control signals after selective filtering are applied, four lines are shown corresponding respectively to 10%, 60%, 80% and 100% motor torque. Assuming the 80% torque (normal speed) conductor is energized the motor converter controls the power necessary to provide this torque. The speed control can be modified by signals received from trackside equipment which operate contacts on the vehicle 3, e.g. when entering a spur line contactor 394 is operated to switch flip-flop 393 to a position in which it applies a signal to AND gate 397 which is also supplied with the 80% signal-the output from the gate controls a gentle braking. Subsequent operation of contact 395 produces coincidence in AND gate 404 and a 10% torque signal is applied to the motor converter. The indicator board 164 on which a code representing the destination required by the passenger is set up, may include a number of electromagnets which are read by magnetic reed contacts positioned adjacent the track or may include a number of lamps detected by photo-electric apparatus. The code is read adjacent each station and associated points operating apparatus is energized when a vehicle carrying a code for a particular station is detected. Means are also provided for setting up an emergency code by which the vehicle is routed to the first available station and a general code by which an empty vehicle may be switched into a station at which a vehicle is required.