A pilot operated relay valve (10) for an air pressure braking system includes a relay piston (16) which is responsive to the pressure at a control port (20) to open the valve (10) so that it's inlet port (38) is in free communication with it's outlet port (24). The relay piston (16) includes a balance orifice (26) which permits the outlet port (24) to communicate with the control port (20) to equalized or balance the pressure differential therebetween. A shut off valve arrangement (80,82) or a c...

A pneumatic tractor-trailer brake system by which application of the trailer brakes and the tractor brakes occurs simultaneously to guard against jack-knifing. This is accomplished by connecting the pressure chamber of the relay valve on the trailer and the adjacent end of the service line with the air pressure tank on the trailer by opening a normally closed solenoid-actuated valve as a consequence of initial depression of the brake pedal. Energization of the solenoid to open this valve results...

A relay valve for use in a vehicle air brake system includes a movable piston and a movable shuttle controlling the flow of air pressure between a supply port, a delivery port and an exhaust port. The piston has a seal in alignment with a seal on the shuttle, which seals are effective, when the piston has closed upon the shuttle, to create generally equal and opposite air pressure responsive areas on the piston to balance it within the valve. In like manner, the shuttle has spaced seal members, ...

A brake activation system for reducing the time between the brake application of tractors and trailers utilizes a speed differential between the electrical and air signals. The application of the tractor brake actuates simultaneously a stop light circuit and the air brake systems. The electrical signals from this energized stop light circuit actuates solenoid valve which releases the air from the trailer reservoir being subsequently reduced to a predetermined low pressure level. This low pressur...

A vehicle motion control device is configured to determine whether the lane in which the vehicle is traveling is straight or curved. If the road is curved, a target yaw rate is set such that the yaw rate of the vehicle to the target position is averaged. If the road is straight, the target yaw rate is set such that the response delay does not exceed a target value. Therefore, wavering of the vehicle with respect to the lane is suppressed, and the vehicle is controlled to move smoothly when the r...

Digital application and release brake control signals generated by an electronic operating unit in accordance with the difference between a desired retardation signal and the available dynamic brake effort are provided to control a pair of thyristors in an a.c. control circuit for energizing one or the other of separate field windings of a torque motor, the output shaft of which drives a pneumatic relay valve device between application, lap and release positions, accordingly. The output of the r...

A quick acting three-way valve that operates a poppet with a lost motion connection. A sleeve is sealed through the diaphragm. A solid or hollow sleeve may be employed with a hollow or solid poppet, respectively. If either the sleeve or the poppet is hollow, the other may or may not be, as desired. An exhaust port is provided in communication with either one or both of the hollow interiors of the sleeve and poppet, the exhaust port being provided through the valve body.

A first piston is displaceable in a housing and has a first piston portion having a larger effective surface and movable in one direction. A second piston portion normally disengaged from the first piston portion has a smaller effective surface and is moveable in an opposite direction into operative engagement with the first piston portion. The second piston is spaced from and defines with the first piston portion a chamber. A first inlet communicates with this chamber and is at the pressure pre...

In its simplest form, the valve comprises a body with an inlet connector and an outlet connector intended to be connected to a pressure source and a pneumatic circuit respectively. In the body, a valve comprising a seat and an obturator controls communication between the connectors. A control piston is sealingly slidably mounted in the body and, in its working travel, can cause controlled movement of the obturator away from the seat to cause controlled opening of the valve. According to the inve...

An air diffuser assembly has a plurality of hat-shaped members which individually fit over individual parallel spaced panels of a suspended ceiling structure to locate upper and lower flange baffles of adjacent members in the spaces between the panels. The upper baffle or weir forms a throat between the free edge thereof and the vertical portion of the adjacent members to regulate the flow of air therethrough while the lower baffle acts as a vane to deflect the air flowing through the throat alo...