EINRICHTUNG ZUR SIGNALUEBERTRAGUNG VON EINEM DREHTEIL AUF EIN BEZUEGLICH DES DREHTEILS DREHFESTES TEIL INSBESONDERE VON EINEM FAHRZEUGRAD AUF DAS FAHRZEUG.

摘要

A flat ring, rotating concentrically with a wheel, has alternate teeth (2) and notches (3) which induce an alternating signal in a sensor (5) at a frequency proportional to speed. A waterproof plastics housing (6) contg. a magnet (7) is mounted in the toothed face of the ring at a radius which puts its orbit opposite the sensor (5). A displacing mechanism (8) moves the magnet in or out according to tyre pressure on that wheel so that, depending on magnet distance, the regular train of signals from the sensor (5) is disturbed once per revolution and a low tyre pressure condition detected by electronics which also measure wheel speed. Since the magnet can approach very close to the sensor, effects of clearance tolerance between sensor and disc do not affect operation.