Abstract: A compressed air system includes an air compressor the inlet of which is communicated to the vehicle engine turbocharger. The outlet of the air compressor is communicated through an air dryer to a storage reservoir. A governor is responsive to the pressure level in the reservoir to generate an unloading signal unloading the air compressor when the pressure in the reservoir attains a predetermined value. The unloading signal is also communicated through a control valve to purge the air dryer during compressor unloading. The control valve closes communication between the governor and the air dryer to trap a predetermined pressure level in the purge volume of the air dryer to prevent the air dryer from purging to atmospheric pressure. Accordingly, a predetermined air pressure level is maintained in the purge volume, so that the outlet of the turbocharger can never be communicated to atmospheric pressure.

Abstract: A dual circuit brake valve includes a plunger assembly carrying the primary valve seat, and the primary valve plunger within the primary piston. A pair of axially-spaced, circumferentially extending bearing members extend from the primary piston slidably engaging larger and smaller diameter portions of the bore of the housing to thereby guide the primary piston independently of other components within the housing. The secondary set of valve actuating members is actuated by a relay piston which is similarly guided in larger and smaller diameters of the bore independently of other components within the valve housing. The primary piston defines a pressure effective area due to the difference in the larger and smaller portions, so that inlet port pressure acting on the effective area yieldably urges the plunger toward the brake released position.

Abstract: A dual circuit brake valve includes a relay piston (50) having primary (82) and secondary (84) areas which are normally communicated to the pressure level at the primary outlet or delivery port (18). The relay piston (50) responds to a pressure differential across the relay piston to control communication to the secondary outlet or delivery port (22). A control mechanism (92) is responsive to a control signal to vent the secondary area (84) to thereby establish a differential area across the relay piston (50), so that the relay piston (50) will establish a pressure level at the secondary outlet or delivery port (22) which is a predetermined fraction of the pressure level at the primary outlet or delivery port (18).

Abstract: A flotation riser having a series of annular chambers with a riser string extending in free-standing relation through said chambers, means for supplying gas to the chambers to control buoyancy, means to supply gas to a plurality of the lowermost chambers to provide an emergency supply of deballasting gas, and means for remotely releasing said supply of gas into the chambers above to render the flotation riser free-standing to permit release from the floating platform during emergencies. A method of storing emergency deballasting gas and for emergency deballasting of the chambers to render the flotation riser freee-standing including the steps of supplying gas to the lowermost chambers, retaining the gas in said lowermost chambers, and remotely releasing the gas and conducting it to higher chamber to deballast such chambers sufficient so that said flotation riser is free-standing.

Abstract: A three way check valve for a vehicle fluid pressure braking system includes a housing having first, second and third inlet ports and an outlet port. A pair of shuttles are slidably mounted in the housing, and are responsive to variations in the fluid pressure at the first, second and third inlet ports to communicate the inlet port having the highest pressure level to the outlet port, and to terminate communication through the other inlet ports to prevent back-flowing from one inlet port to the other inlet port.

Abstract: An electro-pneumatic control system (10) for a vehicle fluid pressure braking system controls communication to the trailer supply line (30) and to the vehicle spring applied, fluid pressure released parking brakes (78). Relays (66,92) are controlled by manually actuated switches (42,58) to actuate solenoid valves (74,84) which control communication to the supply line (30) and to the parking brakes (78). Actuation of the solenoid valves (74,84) is maintained by the relays (66,92) in response to pressure actuated switches (76,88) which are responsive to the pressure levels in the supply line (30) and in the parking brake (78).

Abstract: A fluid pressure braking system for an articulated vehicle having a towed unit and a towing unit includes a source of fluid pressure carried on the towing unit and a supply line (58) and a service line (62) which communicate the braking system on the towing unit with the braking system on the towed unit. A first proportioning valve (76) controls communication to the relay valve (84) which controls communication of braking pressure to the rear wheel service brakes on the towing unit. The proportioning valve (76) is controlled by an inversion valve (90) which is responsive to the pressure level in the supply line (58). When the pressure level in the supply line (58) is below a predetermined level indicating that the towing unit has been disconnected from the towed unit, the inversion valve (90) causes the proportioning valve (76) to proportion communication to the relay valve (84).

Abstract: The service and emergency braking system for use on articulated vehicles having service brakes actuated by air pressure and having emergency brakes held in a released condition by air pressure. The system includes valving which is responsive to a pressure differential between the fluid pressure level in the service line connecting the portions of the articulated vehicle and a reference pressure, so that the emergency brake control is vented during a service brake actuation to permit the emergency brakes to effect a brake application when the pressure of the service line drops below the reference pressure by a predetermined amount, thereby providing braking on all portions of the vehicle in an emergency braking situation when the service brake line interconnecting the portions of the vehicle has been broken or has been left disconnected.