Patent GB-1399361-A (GB)
Title: Transportation systems
Inventor: WESENER E
IPC: B61L3/18
Filed: 1972-08-11
Abstract: 1399361 Control of vehicles in railway systems BURO PATENT AG 11 Aug 1972 [13 Aug 1971] 37658/72 Heading B7N [Also in Division H2] A railway system comprises individually propelled vehicles la, 1b on rails 3 each with an electric driving motor 17 which picks up current via contacts S 1 , S 2  from conductor rails 3, each vehicle, when considered in the direction of movement F, having a front and rear contact element B 2 , B 1  respectively such that should one vehicle, 1b, abut a preceding vehicle, la, via contacts B 1 , B 2 , the electric power to motor M of vehicle 1b will be cut off by actuation of a relay E in a control circuit for the motor, Fig. 2. In Fig. 2 a reversing switch W is electrically reversed when the vehicle direction changes so that the rear contact B 1  or B 2  always connects with the current source, e.g. S 2 . The front contact is always then connected with the relay E whereby on contact between two vehicles the front contact of the rear vehicle is energized, thereby opening the normally closed relay E, and interrupting the electric supply to motor M. A switch Z is coupled to a hinged cover 5 of the vehicle and is closed when the cover is open thereby preventing movement of the vehicle with an open cover. In the alternative control circuit of Fig. 3, a resistance matrix R 1 -R 4  ensures that the rear contact of a vehicle is at a greater potential then the front contact. This is achieved by providing oppositely poled diodes D 1 , D 2  in parallel with resistors R 3 , R 2  so that depending on the direction of travel one or other of these resistors is short circuited. A switch Z is also provided connected with cover 5 as in the circuit of Fig. 2. The switch G which interrupts the current to relay E contains a differential amplifier with transistors T 1 , T 2 . If the vehicle is not making contact with a preceding vehicle the voltage at point A is smaller than the threshold value of the amplifier and T 1  is not conductive. Upon such contact T 1  becomes conductive and a transistor circuit containing transistors T 3  and T 4  is switched. Thus relay E is energized and the current to motor M interrupted. Really E is provided with an additional contact which short circuits the motor via resistor R 16  and brakes it. A further contact of the relay operates a timing circuit containing capacitor R 1 . R 1  is discharged via resistor R 7 , the base-collector path of transistor T 1  and resistor R 9  so that a time delay of 2À5 seconds is obtained after contact between the vehicle and a preceding vehicle is broken and the motor M re-energized. To ensure switch G on charging the current direction in the conductor rails always receives current of the same polarity a bridge circuit of diodes D 3 -C 6  is provided. A diode D 7  in the timing circuit ensures than on switching on of the current and when several vehicles have been in contact the voltage at the base of transistor T 1  does not fall below the threshold value. Diode D8 in parallel with relay E removes voltage peaks upon operation of the relay. The circuit is designed to operate at 10-30 volts.