Abstract: A speed sensor for an adaptive braking system is disclosed. The sensor is enclosed in a housing, so that all critical adjustments may be made at the time the sensor is manufactured and not when the sensor is installed on the vehicle. The entire sensor package is small enough to be mounted within the tubular axle used on many relatively large vehicles, such as semi-trailers, which are in use today. A driving connection is provided between the speed sensor and the hub cap of the vehicle, which of course, rotates with the corresponding vehicle wheel.

Abstract: A clutched fan drive for a vehicle engine is disclosed which couples the engine cooling fan to a member driven by the vehicle engine when the engine coolant temperature exceeds a predetermined level, and which uncouples the fan when the engine temperature level falls below the predetermined level. The fan drive includes a driving member which is rotatably mounted on a fixed spindle, a ram piston which is slidably mounted on the spindle, and a driven member which is rotatably mounted on the ram piston and which is movable therewith. The engine coolant fan is coupled to the driven member, and both the driven member and the driving member are provided with a clutching mechanism which is engaged by a resilient spring which acts against the ram piston.