Warning of towed vehicle tyre deflation - is provided by pressure sensitive membrane acting on electrical contact

摘要

A vehicle being towed has a signalling system which warns the driver of towing vehicle that the pneumatic tyres of towed vehicle have deflated. Pneumatic air pressure passing along a pipe from a valve on a tyre acts on manometric pressure membrane to press a piece against a spring. A metal contact is pressed away from the base to open an electric circuit via metallic connection to a wheel nut. Loss of pressure allows the spring to close electrical contact to signal warning in towing vehicle via electricalconductor.