| 摘要 |
PURPOSE:To exactly detect a vacant or occupied state of an unloading position of the ground side, by providing a reflecting means on a position opposed to a light emitting means and a light receiving means in a shape for placing the unloading position between them. CONSTITUTION:To the left end part on a ground conveyor 4, a reflector 11 is attached so that its reflecting surface turns to a recursive reflection type photoelectric tube 10. In this state, in case light beams have been emitted to the reflector 11 from a light emitting part 10a of the tube 10, when an unloading position P2 is vacant, strong reflected light beams by the reflector 11 are made incident on a light receiving part 10b, and a signal of an L level is outputted to a controller from the tube 10. In this way, an unloading car 1 executes unloading. However, in case the position P2 is occupied, the reflected light beams by the reflector 11 are not made incident on the light receiving part 10b, and as a result, a signal of an H level is outputted to the controller from the tube 10. As a result, the unattended car 1 stops unloading. Also, in case of a pallet 2, the same detection can be executed by placing the reflector 11 in a position opposed to the tube 10 in a shape for placing the pallet 2 between, on an unloading position P3.
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