Abstract: Within a single envelope or housing, this full-function valve integrates all of the emergency and service requirements of a tandem axle air brake system for heavy duty truck semi-trailers, thereby decreasing complexity and cost and enhancing safety, reliability and operating capability while also satisfying applicable Federal Regulations. The housing encloses a spring brake valve module, a relay valve module and a biased one-way pressure protection valve, all interconnected to meet operating requirements, while preventing non-intentional spring brake engagement, foreclosing trailer movement without adequate service brake capability and optionally providing anti-compounding protection.

Abstract: A retracting strap plate clutch assembly having a single annular body strap plate affixed to a clutch pressure plate has integrally preformed spring resilient tabs mounted to the clutch housing. The tabs are normally spring loaded to retract the strap plate toward the diaphragm spring so that when the clutch is released the tabs cause the pressure plate to smoothly disengage from a friction disc.

Abstract: A governor-controlled pneumatic braking system for use with vehicles equipped with an internal combustion engine having a unit associated therewith for discharging engine exhaust gases. The system includes an air dryer to effect removal of moisture and contaminants from the compressed air. The air dryer is provided with a unit for reversely flowing purge air therethrough when the compressor is not operating in the loading or compressing cycle. A conduit are provided for subjecting the purge air exhausting from the dryer to high temperatures so as to cause vaporization of moisture and combustion of combustible contaminants thereby preventing their discharge into the environment.

Abstract: In a heavy-duty truck having a turbocharged internal combustion engine and a lubricating system wherein lubricating oil from the engine oil reservoir is circulated both within the engine and also to and from an associated brake system air compressor, supercharged air is passed to the oil crankcase of the air compressor to cause lubricating oil to drain therefrom and return to the engine oil reservoir. This minimizes windage and resulting engine power losses, reduces oil consumption and avoids problems associated with the undesired entry of lubricating oil into the brake system via the air compressor.

Abstract: This apparatus is a fastener assembly for retaining a spring, such as used in the brake actuators of heavy-duty trucks, in a compressed state, including a fully-compressed state, the assembly being variably adjustable to accommodate variations in actual spring dimensions and tolerances. The compressed spring is held between first and second members by a fastener assembly comprising a washer and a clip, the washer having an opening therein for receiving the clip. The clip has an enlarged head with sloping shoulders which ride on the periphery of the opening in the washer, and a shank which engages the second member and maintains the clip stationary with respect thereto.

Abstract: In its broad aspect, the present invention involves a governor-controlled gas compressor system for maintaining gas pressure in a gas reservoir between a predetermined first pressure level at which said compressor commences to compress pressurized intake gas from a supercharged source thereof and a predetermined higher second pressure level at which the compressor ceases to compress said gas. The system includes a gas dryer vessel intermediate said compressor and said reservoir to effect drying of the compressed gas. The gas dryer is provided with means for exhausting purge gas therefrom only when the pressure of the purge gas exceeds the pressure of the pressurized intake gas from the supercharged source thereof.

Abstract: A pressurized fluid control module is provided for a tractor-trailer brake system to effect the appropriate braking function.

Abstract: The compact, integrated, multi-function valve employed in semi-trailer brake systems having a plurality of pressurized air reservoirs comprise a plurality of internal passageways and ports communicating externally, a plurality of internal control means for interrupting or establishing fluid communication between the various internal passageways and a plurality of one-way means to ensure the integrity of the brake system in the event of leakage problems with one or the other of the pressurized air reservoirs. A preferred embodiment of the brake valve employs four sets of internal passageways and ports, two control means and two multi-function one-way means. As compared with the prior art, the improved brake valve protects the integrity of the brake system with less complexity, fewer components and the potential for enhanced reliability, reduced maintenance and overall lower costs.

Abstract: An automatic slack adjuster for over-the-road vehicle brakes is adapted to be mounted between the brake chamber and brake operating shaft, for example an operating shaft known as an S cam shaft. The slack adjuster includes a body having a lever arm pivotally connected thereto, which lever arm is connected to the brake chamber through a brake operating rod. A drive member is fixed onto the brake operating shaft and is movably positioned within the body. There is an adjustable connection between the lever arm and the drive member for adjusting the relationship between the drive member and body in response to the body movement required for a brake application. The adjustable connection provides for incremental adjustment and is responsive, during brake application movement of the lever, for both sensing and taking up a limited amount of slack.

Abstract: An isolation valve is provided for use in a pneumatic system having an air compressor operable in normal and unloading modes, an air dryer, a reservoir of charged air, and a governor. The isolation valve includes a housing provided with an internal cavity and having a first port to the cavity communicating with a first port of the compressor, a second port to the cavity communicating with an inlet port of the dryer, and a third port to the cavity communicating with a port of the governor. A pneumatically responsive primary valve member is mounted within the cavity for movement between open and closed positions with respect to the housing second port. The primary valve member is provided with an internal passage having one end in communication with the housing third port and a second end in communication with the housing cavity. A pneumatically responsive secondary valve member is mounted within the passage for movement between blocking and unblocking positions.