Abstract: A braking system for a combined tractor-trailer assembly wherein a leading trailer is coupled to a towing tractor and a trailing trailer is coupled to the leading trailer. All of the wheels of the trailers are provided with brakes which may be applied and released in response to the operation of a brake control pedal operated by a driver in the tractor. The brakes also may be applied to the trailing trailer whenever the latter is parked. The brakes of the trailing trailer normally are maintained in applied condition by a spring assisted mechanism when such trailer is parked. Such mechanism normally is disabled by pressurized fluid when the trailer is in service and the pressured fluid is accessible via a valve which simultaneously enables the parking brakes and service brakes simultaneously to be coupled to and uncoupled from the pressure fluid system.

Abstract: A braking system for a combined tractor-trailer assembly wherein a leading trailer is coupled to a towing tractor and a trailing trailer is coupled to the leading trailer. All of the wheels of the trailers are provided with brakes which may be applied and released in response to the operation of a brake control pedal operated by a driver in the tractor. The brakes also may be applied to the trailing trailer whenever the latter is parked. The brakes of the trailing trailer normally are maintained in applied condition by a spring assisted mechanism when such trailer is parked. Such mechanism normally is disabled by pressurized fluid when the trailer is in service and the pressured fluid is accessible via a valve which simultaneously enables the parking brakes and service brakes simultaneously to be coupled to and uncoupled from the pressure fluid system.

Abstract: A braking system for a combined tractor-trailer assembly wherein a leading trailer is coupled to a towing tractor and a trailing trailer is coupled to the leading trailer. All of the wheels of the trailers are provided with brakes which may be applied and released in response to the operation of a brake control pedal operated by a driver in the tractor. The brakes also may be applied to the trailing trailer whenever the latter is parked. The brakes of the trailing trailer normally are maintained in applied condition by a spring assisted mechanism when such trailer is parked. Such mechanism normally is disabled by pressurized fluid when the trailer is in service and the pressured fluid is accessible via a valve which simultaneously enables the parking brakes and service brakes simultaneously to be coupled to and uncoupled from the pressure fluid system.

Abstract: A braking system for a combined tractor-trailer assembly wherein a leading trailer is coupled to a towing tractor and a trailing trailer is coupled to the leading trailer. All of the wheels of the trailers are provided with brakes which may be applied and released in response to the operation of a brake control pedal operated by a driver in the tractor. The brakes also may be applied to the trailing trailer whenever the latter is parked. The brakes of the trailing trailer normally are maintained in applied condition by a spring assisted mechanism when such trailer is parked. Such mechanism normally is disabled by pressurized fluid when the trailer is in service and the pressured fluid is accessible via a valve which simultaneously enables the parking brakes and service brakes simultaneously to be coupled to and uncoupled from the pressure fluid system.

Abstract: A tool structure is arranged to include a pneumatic chamber with a piston and rod mounted and directed through the chamber coaxially thereof, with a forward end of the rod terminating in a rectilinear plate received through a slot within a pneumatic reservoir of a pneumatic brake organization. The rectilinear plate is arranged for engaging a forward end of a spring member within the pneumatic brake reservoir and its compression therewithin upon application of pneumatic pressure within the tool chamber. A modification of the invention includes an alignment block received within the brake chamber to effect a latching of the engaging plate in a retracted orientation preventing its rotation.