Method and device for measuring distance and pressure inside an air spring

The method involves providing an ultrasonic pulse measuring arrangement with a transmitter circuit, a transducer mounted on the cover plate, a reflector mounted in the air spring and a target reflector on the roll off piston. The difference in impedances of the transducer and the air present inside the air spring generates a reference signal. The amplitude and running time of the generated signal are then calculated. An Independent claim is also included for the apparatus for determining the pressure in the interior space of an air spring.