Safety air brake system for automotive vehicles

Claim 1

A SAFETY AIR BRAKE SYSTEM FOR AUTOMOTIVE VEHICLES COMPRISING, IN COMBINATION, AN AIR RESERVOIR HAVING A FIRST AND A SECOND CHAMBER, INDEPENDENT OF EACH OTHER; CHECK VALVES ON EACH SAID CHAMBER FOR THE ADMITTANCE OF COMPRESSED AIR; FRONT WHEEL BRAKING MEANS CONNECTED TO SAID FIRST CHAMBER; REAR WHEEL BRAKING MEANS CONNECTED TO SAID SECOND CHAMBER; A RELAY VALVE DISPOSED BETWEEN SAID SECOND CHAMBER AND SAID REAR WHEEL BRAKE MEANS AND OPERATED BY THE ACTUATION OF SAID FRONT WHEEL BRAKING MEANS; A BRAKE VALVE; A BRAKE PEDAL FOR OPERATING SAID BRAKE VALVE, SAID BRAKE VALVE BEING DISPOSED BETWEEN SAID FIRST CHAMBER AND SAID FRONT WHEEL BRAKING MEANS; A SAFETY DEVICE INCLUDING A PISTON NORMALLY SUBJECTED TO THE AIR PRESSURE OF SAID FIRST CHAMBER ON ONE SIDE AND TO THE AIR PRESSURE OF THE SECOND CHAMBER ON THE OTHER SIDE, AN AIR VENT FOR SAID REAR WHEEL BRAKING MEANS, A VALVE FOR OPENING AND CLOSING SAID AIR VENT, RESPONSIVE TO THE DISPLACEMENT OF SAID PISTON, AND A CHECK VALVE FOR PASSING THE COMPRESSED AIR FROM SAID SECOND CHAMBER BY WAY OF SAID RELAY VALVE TO SAID REAR WHEEL BRAKING MEANS WHEN SAID AIR VENT IS CLOSED; A CHANGEOVER VALVE FOR EQUALIZING THE PRESSURES ON BOTH SIDES OF SAID PISTON WHEN SAID BRAKE PEDAL IS RELEASED SO AS TO VENT THE COMPRESSED AIR REMAINING IN THE BRAKING MEANS THROUGH SAID AIR VENT.