illegal probe in a warning device for displaying the descent of the air pressure in force carriage air tires

摘要

An alarm device signals a substantial drop in the inflation pressure of the tires on the wheels of an automotive vehicle. The device comprises a portion of an electric circuit located at the free end of a flexible rod which is covered with a layer of material of low resistance subject to abrasion. The covering material is removed by abrasion as the vehicle travels over the road if tire pressure is low. The electric circuit, consisting of two wire-like elements, may be either normally closed or normally open. In the latter instance, the separated wires are fused together. In both embodiments, this change in the condition of the circuit causes an alarm to be set off.