Abstract: Air-drag powered devices are provided for automatically maintaining a target inflation pressure or for equipping vehicle wheels with additional functionality. One illustrative device embodiment is an air compressor that attaches to the wheel of a vehicle to turn with the wheel as the vehicle moves. A drag member extends from the body of the air compressor to alternately present opposing surfaces to the air through which the vehicle passes. The air drag on the member thus creates an alternating drag force that powers the air compressor. Another illustrative device embodiment is an energy harvester that attaches to the wheel of a vehicle to turn with the wheel as the vehicle moves. A drag member attached to the base of the energy harvester presents alternating surfaces to the air through which the vehicle passes to derive a reciprocating motion suitable for generating electricity usable for powering wheel-mounted sensors or lights.

Abstract: A tire inflation system having a spindle, a pump actuating member, and a pump. The pump actuating member may actuate the pump when the pump rotates about an axis, thereby causing the pump to output a pressurized gas.

Abstract: This is an invention for a system and method of automatically inflating the wheels of a vehicle during driving operation. When air pressure in a wheel of the vehicle decreases below a pre-determined limit, a solenoid device is activated to extend a kick-rod. As the wheel rotates, a pump mounted on the wheel strikes the kick-rod of the solenoid device, thereby causing air to be injected into the wheel. The automatic tire inflation system works by employing the mechanical energy of the rotating wheel to drive the pump upon contact with the solenoid device.

Abstract: A device for maintaining inflation pressure within a tire interior of a tire mounted on a rotating wheel with a rim. The device includes a compressor with piston penetrateably mountable on the wheel rim or in communication with a valve stem that incorporates air delivery to the compressor as mounted within the tire. The piston is in communication with a compressible piston driver having a distal end in contact with the inner floor of the mounted tire where the outer side of the tire contacts the ground once every revolution of the wheel. Repeated deformation of the rotating tire where it contacts the ground outside the distal end of the driver is transferred to the air compressor through a piston compression stroke. When such ground contact is not occurring, centrifugal force causes radial movement to accomplish the intake stroke of the piston. In this repetitious manner a small amount of air is forced into the tire during each rotation thereof when needed to maintain desired inflation pressure.