Abstract: An electrical circuit element (16) is maintained in place within the drop center (24) of a vehicle wheel (10) by encasing the circuit within a cylindrical plastic housing (14) which is formed into an arcuate shape. The housing is held in place by wires (18, 19) which are connected to the ends of an extension spring (22) which applies sufficient tension to keep the housing from moving during heavy braking or due to centrifugal force. The mounting assembly is configured to move to an out of the way position when contacted by a tire iron or by elements of a tire mounting machine to prevent damage to the circuit when a tire is mounted or demounted. In accordance with another embodiment of the invention, the circuit (16) is encased within a unitary annular member (56).

Abstract: A combined unloading valve and check valve (10) for use with a motor driven air compressor. The unloading valve (16) includes a spool (30) axially movable within a tubular body (12). In the unloading position of the valve, one of two spaced-apart ring seals (32) on the spool is out of engagement with the body to open a flowpath from the inlet of the valve past the spool to exhaust ports (28) formed in the body. When the compressor is operating and the valve is pressurized, both ring seals engage the body to close off the flowpath. The check valve (18) extends beyond the end of the body and includes a poppet valve element (50) which engages a valve seat (52) formed on an end of the spool. When the unloading valve and check valve is installed in a wall (14) of an air tank the check valve extends into the air supply within the tank, thereby helping to cool the internal elements of the valve structure.