POWER WINDOW-USE SAFETY DEVICE

摘要

A power window-use safety device which is not likely to make an erroneous judgment due to variations in a battery voltage and which is a safety device that generates pulses by the rotation of a motor for moving up/down the windowpane of a vehicle-use power window and judges foreign matters being caught by monitoring a variation in pulse width during a window closing operation to reverse it to a window opening operation. The safety device comprises a storing unit for storing the pulse width change rate of continuous pulses detected by a pulse width detector during a windowpane moving up operation at a reference time in conjunction with window position information by a window position counter, a computing unit for computing continuous pulse widths detected by pulse width detector during a windowpane moving up operation in conjunction with window position information by the window position counter, and a control unit for comparing the stored value of a pulse width change rate in conjunction with window position information by a storing unit with computed value of a pulse width change rate in conjunction with window position information by the computing unit and driving the motor for moving up/down in a windowpane opening direction when a total of differences between the both pulse change rates exceeds an allowable value.