| 摘要 |
PURPOSE:To keep an automatic detector from generating an error signal, by juxtaposing a plurality of detection switches, connecting their circuits in series with each other and preventing wrong action from being caused by passing of a working person. CONSTITUTION:A detector detects a car body 2 carried by a slat conveyor 1, in order to cause an automatic working equipment to surely operate. The detector comprises photoelectric tubes PH1-PH4. When rays of light are intercepted for a prescribed time due to passing of the car body 2 in front of the photoelectric tube PH1, a timer TR1 acts to turn off a switch Tr1. When the photoelectric tubes PH2-PH4 are thereafter put in the same condition, a next working equipment is driven by the action of a relay CR3. With only the interception of rays of light to the photoelectric tube for a short time, the detector does not act. Only proper action is thus obtained. |
