Automatic control of automobile windscreen wiper operating rate - has sweep rate increased if sweep cycle time is above preset threshold, owing to reduced friction from moisture

摘要

The automatic control procedure for operating rate of wind-screen wipers regulates the rate as a function of the sweep time of the blades on the windscreen. It favours the growth of the rating period to a raised value if the sweep time is greater than a calculated threshold value and favours the decrease of the rating period towards continuous functioning of the blades if the sweep time is less than the calculated threshold. The device acts on an electric motor which drives the wind-screen wiper blades. It comprises a fast-stop signal generator associated with the motor to form a signal whose waveform is a function of the sweep time, an operating mode selector having an "automatic rating" position, and a calculating unit fed by the fast-stop signal and by signals coming from the operating mode selector which deduces the control signals to act on the motor according to the described procedure.