Patent GB-1340508-A (GB)
Title: Transportation systems
IPC: B61L27/04
Filed: 1970-12-02
Abstract: 1340508 Transportation system ALDEN SELF-TRANSIT SYSTEMS CORP 2 Dec 1970 [5 Dec 1969] 57256/70 Heading B7N In a transportation system main and subsidiary tracks 100, 146, &c. are divided into segments defined by conducting elements 222 to which control signals are applied in sequence to produce control areas moving along the tracks and a vehicle in a moving control area is controlled by the signals to maintain its position therein. Each vehicle includes two steerable front wheels 244, coupled to guide groove followers and a drive motor 250 for the rear wheels 266 has one input via pick up shoes 254 from lineside power conductor 216 and a second input from servo amplifier 258 which is connected to line side ground conductor 218 and segmented control conductors 222 via pick up shoes 265, 262 respectively. The segmented conductors, which are resistance elements are arranged in groups of three-222 A, B, C, and each segment in a group is connected to one of three control line pairs 270, 271; 272, 273; 274, 275 extending along the track. The control lines are connected via switches 291 A, B, and C which are stepped at a rate which is a function of the speed required for the system vehicles, to a sensing circuit which supplies a sensing interval signal and to two pulse generating circuits including switch elements 300, 304 which supply first and second control interval signals. These signals are applied via the switches in offset sequence to the segments and define successive areas of length equal to three segments which circulate around the system at a rate determined by the switching rate. Each control interval signal, e.g. that supplied by switching element 300 comprises a number of pulse cycles each having a fixed amplitude and duration positive portion and a fixed amplitude negative portion which increases in duration at a rate which is a function of the required speed of the vehicles. The positive part of the signal is applied across a segment so that the vehicle pick up and the resistive segment act as a potentiometer to pick up a positive part signal which increases in amplitude at a rate which is a function of actual vehicle speed. At the same time the average value of the negative part of the signal increases at a rate which is a function of required speed. The two parts are compared to produce an error signal for control of vehicle speed. The last segment of the moving area is supplied from terminal 294 and when a vehicle, due to fault action, drops back into the segment its presence is detected by the drop in voltage which is applied via a conductor 286, which is common to all segments then acting as sensing segments, to a computer controlled apparatus which then controls all the system vehicles to a stop. The system is provided with stations 104, 134, &c. with the segmented conductors varying in length to form deceleration ramps 108, 120, &c. at station entries and launch ramps 110, 136 at station exits. Before each spur in the track, e.g. 148 a fixed ramp R automatically sets the guide groove follower on the vehicle for a particular route, e.g. the spur and if the vehicle is not to be routed to the spur a control mechanism operates to raise ramp D so that the vehicle guide follower is switched to follow the main track. Vehicle presence detectors S are provided at points along the network. The system is controlled by computer controlled apparatus including a series of registers each associated with a part of the network, e.g. main track, alternate track, deceleration ramp, station, launch ramp, through which a word representing a vehicle identification and destination is sequenced in synchronism with its movement around the track network. Amongst other things the system provides speed instructions, launch instructions to position a vehicle in a "free" moving area and routing instructions for the control of the ramps D.