| 摘要 |
PURPOSE:To keep a pressure-sensitive plate clean and to issue an alarm, when foreign matter is adhered to said plate, to perform processing, by constituting the titled apparatus so that the pressure-plate is vibrated for a definite time when the voltage of a detection sensor is reduced to set voltage or less to remove the foreign matter adhered to said pressure-sensitive plate. CONSTITUTION:An opening part is provided to a casing 16 and a pressure- sensitive plate 18 fixed to an elastomer 17 is mounted to said opening part. The pressure-sensitive plate 18 has such a property that output voltage changes corresponding to pressing force from the outside and the pressure-sensitive surface 18a thereof is directed to a cereal feed side and the back surface thereof connects a code 19 to be connected to a control circuit and an oscillation circuit. Thus integrated detection sensor A is fixed to a machine wall 20. The value detected by the detection sensor A is analoguely calculated by a band pass filter 23, an amplifying circuit 24, a rectifier 25, an integrator circuit 26, a comparing circuit 27, a monostable multivibartor 28 and an integrator circuit 29 and, when set voltage or less is detected by a comparator 33, the pressure- sensitive plate 18 is vibrated by an oscillation circuit 21.
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