Midland Brake, Inc.

Jeffery S Johnston

Dario Gross

Richard D Hetfield

Mark Karpinski

Michael G Smith

A pressurized fluid control module is provided for a tractor-trailer brake system to effect the appropriate braking function. The pressurized fluid control module is combined with pressure inlet fittings for the introduction of a pressurized fluid, a plurality of interconnected pressure chambers for selectively actuating the vehicle service and parking brake circuits, a proportioning circuit to vary the fluid pressure to the rear service brakes depending on the presence or absence of the trailer, a protection circuit to prevent the loss of pressurized fluid within the pneumatic brake actuation and release circuit upon detachment of the trailer from the tractor, quick release valves to release residual fluid pressure in the pressurized fluid control module and the trailer service brake circuit upon the cessation of braking effort, module check valves to prevent fluid pressure losses between the chambers, a vehicle rear stop lamp switch sensitive to the fluid pressure in one of the pressure chambers, and a plurality of outlet fittings to the aforementioned service and parking brake circuits. The pressurized fluid control module of the present invention, as a single, integrated, multifunctional unit, obtains control over the tractor rear service brake circuit and parking brake circuit and the trailer service and parking brake circuit depending on the presence of the trailer, the braking effort exerted by the vehicle operator via the foot-actuated treadle assembly service brake valve assembly, the position of the hand-actuated trailer service brake valve, and the position of the manifold push/pull valve.

Combination brake valve module

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.

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Haslett, MI, United States of America

Jeffery S Johnston