| 摘要 |
PURPOSE:To certainly detect even a small obstruction, by outputting the closing signal of a limit switch when a door is closed and allowing a detector to operate for a definite time to detect the obstruction. CONSTITUTION:Light such as infrared rays from a light emitter 2 is taken in a light receiver 2 and a detector such as the light emitter 2 or the light receiver is attached to the outside of a vehicle so as to be made operable when a door is closed while the light signal converted to an electric signal by the light receiver 3 is sent to the amplifier unit of a processor circuit 4 through a cable 5 and the quantity of light taken in the light receiver 3 is measured and processed. Now, if the detectors such as the light emitter 2 and the light receiver 3 are allowed to operate for a definite time after a limit switch 7 outputs a closing signal when the door 1 is closed and an obstruction is caught in the door 1, the quantity of light reaching the light receiver 3 changes and, therefore, it is compared with that when there is no obstruction by the processor circuit 4 to output the presence or absence signal of the obstruction. |
