Abstract: A holder for an electrical connector of the tractor-trailer type includes a bracket for use in attaching the holder to the tractor with the bracket having an opening of a size and shape to receive an aligned connector body and key. A coil spring is attached to the bracket coaxial with the opening and a cap is carried by the spring in position to cover an inserted connector body. There are locking means on the bracket which cooperate with the key to hold the connector body within the holder.

Abstract: A quick release valve for vehicle air brake systems includes a movable valve member positioned to close upon the valve exhaust port which valve member includes a body portion and a diaphragm. The areas of the valve member exposed to the valve supply and brake ports are only slightly different in size thereby permitting operation on the valve member in response to small pressure differentials between the valve supply and brake ports.

Abstract: A circuit breaker adapter that is mounted with any conventional electrical connector receptacle to the truck-trailer body. The circuit breaker adapter is constructed so that it is secured by existing mounting bolts of the connector receptacle in order to minimize installation expenses. The circuit breakers are removably locked to the adapter so that they may be individually replaced when necessary.

Abstract: A connector receptacle which includes removably locked male contact pins, a locking plate and an end plate. The locking plate can either secure the male contact pins in position or allow removal of the male contact pins.

Abstract: Tractor protection valve means for use in the air brake system of a tractor-trailer vehicle combination to protect and maintain the braking system of the tractor includes a pair of valve housings. One of the valve housings (the pilot) is attached to the tractor dash control valve and includes a piston controlling communication between an inlet, a delivery port and an exhaust port. The second housing has a tractor supply port connected to the pilot delivery port, in addition to trailer supply and control ports, a tractor control port, and an exhaust port. The pilot valve attached to the dash control valve contains the control portions of the valve combination with the piston in the other housing being movable in response to air pressure supplied from the pilot to control communications between all of the ports connected thereto.

Abstract: A combination gladhand and shutoff cock includes a dust cover attached to the shutoff cock operating handle and closing the gladhand body air outlet when the shutoff cock is in a closed position. There is a latch effective between the shutoff cock handle and the gladhand body holding the shutoff cock in a closed position and a further latch between the shutoff cock handle and the gladhand holding the handle in an open position.

Abstract: An electrical connector for use on tractor-trailer vehicles includes a receptacle and plug. The receptacle housing has a thickened portion and ribs reinforcing the thickened portion to prevent deformation of the receptacle due to vibration of the attached cable. The receptacle housing has an extended body portion to provide a deeper support for an inserted plug. The plug uses non-rotatably mounted bushings to form the female connectors, which bushings are staked, one to another. A cable mounting collar is attached to the plug housing in such a manner that its mounting groove always faces in a downward direction to prevent moisture from passing into the connector plug.

Abstract: A relay valve for use in vehicle air brake systems has a housing with a service port, supply port, delivery ports and an exhaust port. A piston and shuttle are movable within the housing to control communication between the ports. The shuttle carries a seal member which, in the closed position, is in sealing relation with both the piston and the housing, thereby closing communication between the supply and delivery ports and between the delivery and exhaust ports. There are means to vent pressure buildup behind the shuttle seal thereby preventing accidental blowout of the seal.

Abstract: A tractor-trailer parking control valve includes a spring-biased valve member movable within a chamber to control communication between a spring brake chamber port and an exhaust port and the spring brake chamber port and a source of fluid pressure. In a second chamber within the control valve housing is a two-way check valve which controls the supply of pressure from one of two reservoirs to the chamber of the spring-biased valve member.

Abstract: An empty-load valve structure for a railroad air brake system include a load sensing valve for sensing the loaded condition of a railroad vehicle and a pressure control valve. In one position of the load sensing valve, full pressure is applied through the pressure control valve to the vehicle brakes. In a second position of the load sensing valve, less than full pressure is applied through the pressure control valve to the vehicle brakes. In all positions of the load sensing valve, a piston movable within the pressure control valve is balanced by opposing air pressure created forces.

Abstract: A tractor protection valve for use in the air brake system of a tractor-trailer vehicle combination to protect and maintain the braking system of the tractor includes a housing having tractor supply and control ports, trailer supply and control ports, and a pair of exhaust ports. The housing has a chamber with the exhaust ports being positioned at opposite ends of the chamber. First and second spring-biased pistons are axially movable in the chamber to control communication between the ports.

Abstract: A trailer air distribution valve has a housing, a chamber in the housing and an air inlet port, an exhaust port, at least one service tank port, an emergency tank port and at least one brake chamber port, all in communication with the chamber. A shuttle is movable within the chamber to control communication between the ports and includes a pair of spring biased valves functioning as check valves to control communication between the inlet port and service tank port and the emergency tank port.

Abstract: A gladhand construction is combined with a shutoff cock and means for mounting the combination to a trailer body. A fitting is positioned within a passage of the gladhand body for use in making a connection with a conduit on the trailer and there is a spring-biased bushing intermediate the fitting and shutoff cock for forming a seal therebetween.