Tire condition sensing apparatus

Abstract

Apparatus and method adapted for detecting the profile deflection condition in a wheel structure of the type comprised of a pneumatic tire mounted on a wheel rim and which deflection may be caused by tire under inflation or overloading. A sensing and actuating structure constructed from flexible material having high flex fatigue characteristics to include a body portion and a profile sensor is conveniently mounted to the drop center portion of the rim such that the profile sensor extends into the tire cavity so that it is positively engaged by the inside of the tire wall when tire profile deflection reaches an amount greater than a predetermined maximum amount due to overloading or under inflation, to thereby cause flexure in the profile sensor generally inwardly toward the rim. This flexure causes a piezoelectric device positioned adjacent the profile sensor to provide an electrical discharge. This electrical discharge is electrically interconnected to the radio transmitter for selectively causing energization thereof. The radio signal thus selectively transmitted is received by a receiving unit spaced remote from the wheel to cause energization of convenient indicating means located within the vehicle itself for showing that tire deflection greater than a predetermined maximum amount has been detected.