Fail-safe means for mechanism coupling running gear to vehicle body

Claim 1

A VEHICLE COMPRISING A BODY, A WHEELED UNIT INCLUDING PNEUMATIC BRAKES, MEANS TO COUPLE SAID WHEELED UNIT AND TO UNCOUPLE THE SAME FROM SAID BODY, A TRACTOR CONNECTED TO SAID BODY AND INCLUDING MEANS TO OPERATE SAID BRAKES, A FIRST CONDUIT EXTENDING FROM SAID TRACTOR TO SAID WHEELED UNIT AND OPERATIVELY CONNECTED BETWEEN SAID BRAKE OPERATING MEANS AND SAID BRAKES, AN AIR RESERVOIR AND MEANS ACTUATED BY SAID COUPLING MEANS TO ENERGIZE SAID BRAKES BUT ISOLATE SAID BRAKE OPERATING MEANS ON SAID TRACTOR WHEN SAID WHEELED UNIT IS UNCOUPLED FROM SAID BODY, AND TO RELEASE SAID BRAKES AND RESTORE SAID BRAKE OPERATING MEANS ON SAID TRACTOR WHEN SAID WHEELED UNIT IS FULLY COUPLED TO SAID BODY, SAID LASTNAMED MEANS INCLUDING A SECOND CONDUIT FROM SAID RESERVOIR TO SAID FIRST CONDUIT AND OPERATIVELY CONNECTED TO SAID BRAKES, A CAM OPERATIVELY CONNECTED TO SAID COUPLING MEANS AND A VALVE INTERPOSED IN SAID SECOND CONDUIT INCLUDING A DEPRESSIBLE VALVE STEM ENGAGED BY SAID CAM, SAID STEM BEING COMPLETELY DEPRESSED BY SAID CAM TO OPEN SAID SECOND CONDUIT AS SAID WHEELED UNIT IS UNCOUPLED FROM SAID BODY AND SAID STEM BEING EXTENDED TO A POSITION WHERE THE VALVE CLOSES OFF SAID SECOND CONDUIT AND ALLOWS AIR TO BLEED OFF FROM SAID BRAKES WHEN SAID WHEELED UNIT IS FULLY COUPLED TO SAID BODY, AND A TWO-WAY CHECK VALVE OPERATIVELY CONNECTED BETWEEN SAID FIRST AND SECOND CONDUITS, SAID TWO-WAY CHECK VALVE ACTING TO CLOSE OFF SAID FIRST CONDUIT WHEN SAID VALVE STEM IS COMPLETELY DEPRESSED, SAID TWO-WAY CHECK VALVE BEING FREE TO OPEN SAID FIRST CONDUIT AND ALLOW CONNECTION TO SAID BRAKE OPERATING MEANS AND TO CLOSE OFF SAID SECOND CONDUIT WHEN SAID VALVE STEM IS EXTENDED.