| 摘要 |
PURPOSE:To prevent idle wiping, the damage of a wiping surface, a wiper, and the like by detecting the washer liquid pressure in a washer hose by a liquid pressure sensor to send to a comparator and operating the wiper on the basis of the output of this comparator for preventing dry wiping of the wiper. CONSTITUTION:A washer hose 1 is branched on its way, and at this branch point, a liquid pressure sensor 2 is provided. The sensor 2 detects the liquid pressure in the hose 1, and the output thereof is sent to a comparator 4 via an amplifier 3. When this output surpasses a set level VL equivalent to the lower limit of the lowering of the liquid pressure in the hose, a voltage comparator A2 of the comparator 4 gives an output to turn on transistors T1 and T2 in a timer circuit 5. When the transistor T2 is on, a relay coil RE is excited, and a contact RS is switched over to drive a wiper motor. When the liquid pressure in the hose 1 is abnormally risen to surpass a set level Vu, the voltage comparator A1 keep the transistor T1 off not to operate the wiper. |
