Abstract: The conveyor safety circuit (40) is connected on remotely operated vehicles (12) each having on-board controllers (28) which automatically run along guide rails (18) powered from power rails (20) extending along the guide rails (18). The safety circuit (40) interrupts power to the on-board controllers (28) when neutral is lost or during power down. The safety circuit (40) will provide power to the vehicle (12) during brief interruptions of power or neutral, i.e., brush skips, without vehicle (12) shut down.

Abstract: The assembly (10) is a self-propelled conveyor system including a vehicle (12) having wheels (18) and a motor (16) for moving the vehicle (12) along a track (20). The vehicle (12) includes a speed sensor (24) for sensing actual speed of the vehicle (12) and a location sensor (26) for sensing the absolute position of the vehicle (12) along the track (20). A control (22) receives the actual speed and absolute location signals and drives the vehicle (12) at a speed associated with the absolute position, this value being obtained from a memory (32). The control (22) drives the motor (16) at the selected speed with a feedback signal of actual speed wherein the control (22) may adjust the drive signal when actual speed differs from selected speed.

Abstract: The invention is a conveyor control system having self-propelled vehicles having wheels, each driven by a motor (14) to move along rails. The system includes power rails (18) for supplying power to the vehicle (12) and at least one command rail (20, 21) which transmits a command signal indicative of requested speed. The command rail (20) includes of isolated sections of rail for carrying different command signals along each isolated section to enable the vehicle (12) to travel at different speeds dependent on which section of rail the vehicle is within. The command signal is in the form of a digital half-wave signal on two rails (20, 21). The digital signal is in the form of half-waves each representing a bit of binary coding. The digital signal may include three-phase half-wave coding in order to obtain four bits of coding from a single rail. Each vehicle (12) includes a control circuit (22) which interprets the command signal to drive the vehicle (12) at the requested speed.