Auxiliary brake system and control means therefor

Claim 1

A BRAKING SYSTEM FOR VEHICLES COMPRISING: AN AIR SUPPLY SYSTEM INCLUDING A MAIN AIR RESERVOIR; AN AUXILIARY AIR RESERVOIR; COMPRESSOR MEANS PROVIDING A SOURCE OF PRESSURIZED AIR; CONNECTIONS BETWEEN THE COMPRESSOR, THE MAIN RESERVOIR AND THE AUXILIARY AIR RESERVOIR FOR MAINTAINING PRESSURE IN THE MAIN RESERVOIR AND THE AUXILIARY AIR RESERVOIR; AND A CHECK VALVE, IN THE CONNECTION, SEPARATING THE COMPRESSOR AND MAIN AIR RESERVOIR FROM THE AUXILIARY AIR RESERVOIR PREVENTING LOSS OF PRESSURIZED AIR FROM THE AUXILIARY AIR RESERVOIR TO THE MAIN AIR RESERVOIR AND COMPRESSOR MEANS WHEN THE PRESSURE IN THE AUXILIARY AIR RESERVOIR EXCEEDS THE PRESSURE IN THE MAIN AIR RESERVOIR AND THE COMPRESSOR MEANS INCLUDING A HOLLOW BODY FORMING AN ENLARGED RECESS AND A SMALLER PASSAGEWAY PROVIDING A PART OF THE FLOW PATH BETWEEN THE COMPRESSOR, MAIN AIR RESERVOIR AND AUXILIARY AIR RESERVOIR, THE PASSAGEWAY HAVING A PORTION OF REDUCED FLOW AREA FORMING A VALVE SEAT; A DIAPHRAGM IN THE BODY FOR SENSING A CHANGE IN PRESSURE BETWEEN THE PASSAGEWAY AND THE RECESS; A HOLLOW STEM, AFFIXED TO THE DIAPHRAGM ADJACENT THE CENTER EXTENDING INTO THE PASSAGEWAY, PROVIDING A CONDUIT ACROSS THE DIAPHRAGM, THE STEM BEING OF SUBSTANTIALLY SMALLER DIAMETER THAN THE PASSAGEWAY TO ALLOW FREE, NON-BINDING MOVEMENT THEREBETWEEN; A PROBE, ON THE STEM, EXTENDING INTO THE PASSAGEWAY AT LEAST PART WAY THROUGH THE AREA OF RESTRICTED FLOW CAPABILITY;