Abstract: A braking system (8) comprising: a master cylinder (10); rear brakes (12a,b) communicated to the master cylinder (10); front brakes (14a,b) hydraulically isolated from the rear brakes; an isolation valve (16; 16') interposing the master cylinder (10) and the front brakes (14a,b) having a first state communicating the master cylinder to the front brakes and a second state isolating the master from the front brakes and connecting a pump (42) to the front brakes; a motor (44) for powering the pump (42); a reservoir (54) communicated to an inlet of the pump (42); a control unit (40) for causing front brake pressure to follow rear brake pressure comprising: a first pressure sensor (30) for generating a signal indicative of rear brake pressure; electric proportioning device (94) for generating a commanded front brake pressure signal (P.sub.C); a second pressure sensor (32) for generating a signal of actual front brake pressure (P.sub.

Abstract: A fluid control valve (10) comprising: a fluid carrying core (12) and separatable magnetic field generating portion (14). The fluid carrying core (12) comprises: a magnetic armature (30) movable through a working gap (32) within a thin walled tube (34). The armature includes a first plurality of grooves (100) to permit fluid flow thereacross. The tube is joined to a magnetic first member (50) in a manner to form a leak-free seal (56) generally at one end of the tube. A second member (80) partially seals the other end of the tube and includes second flow means a second plurality of axial grooves (84) for receiving fluid carried to the valve (10) and for communicating same with the armature (30). Various passages are provided to carry fluid to and from the valve. The position and number of passages permit the valve to be used as a two-way valve or as a three-way valve passage means (88;64) for transporting fluid away from the valve (10).

Abstract: A brake (10) capable of functioning as a disk brake and parking brake having engaged and disengaged modes of operation comprising: a piston rod (30) movable with the disk brake piston (14) having a threaded portion (40), a nut (60) rotatably movable on the threaded portion (40) relative to a first stop (52); a pressurizing device (80, 82, 84; 92) for pressurizing the fluid chamber (20) to move the piston (14) and piston rod (30) to respective engaged positions, and a motor (66, 68) for rotating the nut (60) in one of a) synchronism with pressurizing the fluid chamber and b) subsequent thereto so that the nut moves along the threaded portion (40) into a contracting position with the first stop (52) for preventing the piston rod (30) from moving from its engaged position to achieve the parking brake function.

Abstract: A parking brake system comprising a drum brake (200) comprising two shoes (206) outwardly movable relative to a friction surface of a drum (224); an activation device (220, 222) for generating an activation force to move the shoes outwardly to a first position into contact with the drum sufficiently to prevent the drum; a solenoid activated linkage mechanism (230, 240; 322, 352) is provided for maintaining the shoes substantially in the first position.

Abstract: A variable rate shock absorber having the interior of a working cylinder divided by a piston into an upper and lower working chamber. The lower working chamber is connected to a reservoir by a bi-directional valve member. A solenoid valve housed in a hollow piston rod has an actuated state connecting the upper working chamber to the reservoir. The output of the solenoid valve is connected to the reservoir by means of an axially disposed telescoping cylinder passing through the piston and the bi-directional valve member.

Abstract: An electro/pneumatic proportional valve having a housing defining an upper and lower chamber separated by an annular web. An inlet port and exhaust port concentric with the annular web are provided in said lower chamber while an outlet port is provided in the upper chamber. An exhaust cylinder is resiliently disposed through the exhaust port and has a radial flange engaging said annular web to occlude the annular web's central opening. The exhaust cylinder also has an axial bore passing therethrough and exiting through the exhaust port. A piston disposed in the upper chamber has a pintle which is operative to engage the exhaust cylinder with the displacement of the piston and occlude the exhaust cylinder's axial bore. Pilot valves are provided to pressurize the upper chamber in response to a pulse train signal displacing the piston towards the web. The displacement of the piston causes the pintle to engage the exhaust cylinder and unseat it from the annular web.

Abstract: An electro-pneumatic power steering system for an automotive vehicle having a source of pressurized air. The power steering system having a torque sensor generating a torque signal indicative of the torque applied to the vehicles mechanical steering mechanism, a controller generating a pair of mutually exclusive pulse train signals indicative of the direction and magnitude of the applied torque, a pneumatic cylinder linked to the vehicle's mechanical steering mechanism, and a pair of electrically actuated proportional valves for pressurizing one or the other end of the pneumatic cylinder in response to one or the other of the mutually exclusive pulse train signals. The proportional valves venting the opposite ends of the pneumatic cylinder to the atmosphere in the absence of either pulse train signal removing the authority of the power steering system about the zero torque level.

Abstract: An electronic controller for generating a pair of mutually exclusive pulse train signals. The controller having an offset generator for biasing the input signal about a midpoint value, a first and second difference amplifier for generating a first and second difference signal, one difference signal corresponding to the difference between the biased input signal and the midpoint value and the other difference signal corresponding to the inverted difference between the biased input signal and the midpoint value, a saw tooth wave generator generating a saw tooth wave having its valleys clipped to a predetermined value, and a pair of comparators, one generating a pulse train signal in response to the saw tooth wave and the first difference signal and the other generating the second pulse train signal in response to the saw tooth wave and the second difference signal.

Abstract: A positive displacement air delivery system for an internal combustion engine having a multiple chamber positive displacement air pump and a control valve for directing the output of the air pump to either the engine's catalytic converter or to the engine's air intake for supercharging the engine. The control valve interconnects the individual input and output ports of the air pumps chamber in a predetermined arrangement for optimum efficiency of the pump under the various operational modes of the engine.

Abstract: A supercharging system for an internal combustion engine, consisting of a positive displacement air pump mechanically driven by the engine, and an electromagnetic clutch activated during high torque demand operating conditions. The system produces a high torque output in a high torque demand range from a relatively small displacement engine, with economy operation during normal engine operating conditions. A flow modulation control system provides a smooth transition from natural aspiration to supercharged operating conditions and includes a sensing of the pressure drop across the throttle plate and modulation of the supercharger air flow into the engine intake in accordance with the sensed pressure differential. The flow modulation also enables high efficiency supercharging with the engine operating under partial pressure supercharging as required in ascending a grade.

Abstract: A speed-responsive tag axle control system is disclosed including a comparison circuit which is operable when the rotational velocity of one driven wheel of a motor vehicle overruns the opposite driven wheel by a predetermined amount to simultaneously brake the faster driven wheel and shift the vehicle load from the tag axle wheels to the driven wheels. In one embodiment, a pressure fluid motor is connected between the tag axle and the vehicle chassis for normally transferring load from the driven wheels to the non-driven tag axle wheels, said motor being vented by said comparison circuit means to transfer the load back to the driven wheels upon the occurrence of a driven wheel overspin condition.

Abstract: A traction control system is disclosed for use with a vehicle braking system including a plurality of driven wheels connected by differential means, wheel brake means associated with each driven wheel, and spring brake-operating means for operating each of the wheel brakes, respectively, each of said spring brake means including a brake diaphragm operable between brake-engaged and brake-released positions, a locking spring operable to place the brake diaphragm in the brake-engaged position, and a spring diaphragm operable between a normal spring-disabling position and a spring-enabling position in which the locking spring is inoperative and operative, respectively; characterized by the provision of means for generating for each driven wheel a velocity sensing signal, comparison circuit means for comparing said sensing signals to produce a control voltage when the rotational velocity of one driven wheel exceeds another by a predetermined amount, and means operable by said control signal for placing in the spri

Abstract: An air pressure-controlled electrical switch responsive to a change of pressure either above or below a predetermined desired pressure in a vehicle tire, to actuate a magnetically activated system for signaling such tire pressure change. The switch has piston means subject to one end to air pressure in a tire. The piston means is movable from an intermediate position where it normally is maintained by spring pressure and an opposed force imparted by the predetermined desired internal tire pressure which act i opposition on the piston means. The switch is actuated by movement of the piston means in one direction or the other from the intermediate position. The switch is normally closed when the piston means is in the intermediate position. The switch opens when the piston moves in one direction or the other from the intermediate position upon increase or reduction of the tire pressure from the predetermined desired value.