Transport control apparatus for automated guided vehicles

Claim 1

In a transport system having a plurality of automated guided vehicles moving along a defined path having intersections for entering, leaving and crossing said path, apparatus for controlling the passage of said vehicles at said intersections comprising generating means on each of said vehicles for producing a magnetic field, sensing means on each of said vehicles for detecting a magnetic field and producing an output while sensing the magnetic field, a loop-shaped conductor surrounding each of selected ones of said intersections, said loop-shaped conductor being responsive to the magnetic field produced by the generating means in the first of said vehicles approaching within an area of said loop-shaped conductor to produce an induced magnetic field to be detected by the sensing means on subsequent vehicles approaching the area of said loop-shaped conductor, means for halting the movement of said subsequent vehicles in response to the existence of the output produced by said sensing means and the sensing means in each vehicle includes means for differentiating the magnetic field produced by the generating means in said vehicle from the magnetic field induced by another vehicle in said loop-shaped conductor.