Tandem axle spring suspension

Claim 1

A TANDEM AXLE SPRING SUSPENSION ADAPTED TO BE INTERPOSED BETWEEN A VEHICLE FRAME AND A PAIR OF TANDEM AXLES EACH HAVING RUBBER TIRED WHEELS JOURNALLED AT THE ENDS THEREOF, COMPRISING A VERTICALLY MOVABLE BOLSTER ARRANGED UNDER SAID FRAME BETWEEN SAID AXLES AND PROJECTING OUTWARDLY FROM BELOW THE OPPOSITE SIDES OF SAID VEHICLE FRAME, SAID BOLSTER COMPRISING A VERTICALLY THIN AND HORIZONTALLY BROAD RIGID BODY HAVING END PORTIONS PROJECTING BETWEEN THE TIRES OF SAID WHEELS AT EACH SIDE OF THE FRAME, A CROSS ROD FIXED TO THE UNDERSIDE OF SAID BOLSTER GENERALLY PARALLEL WITH SAID AXLES AND HAVING END PORTIONS ARRANGED UNDER AND IN VERTICALLY SPACED RELATION TO SAID END PROJECTING PORTIONS OF SAID BOLSTER, A WALKING BEAM ARRANGED AT EACH SIDE OF SAID FRAME AND EXTENDING LENGTHWISE THEREOF AND JOURNALLED AT ITS CENTER ON AND SUPPORTING THE CORRESPONDING END PORTION OF SAID CROSS ROD, A FRAME BRACKET ABOVE EACH PROJECTING END PORTION OF SAID BOLSTER, AT LEAST ONE VERTICAL HELICAL COMPRESSION SPRING ARRANGED OUTBOARD OF THE SPACE DIRECTLY ABOVE SAID WALKING BEAM AND WITHIN THE SPACE DIRECTLY BETWEEN THE TIRES OF THE WHEELS AT EACH SIDE OF THE FRAME AND HAVING ITS LOWER END SEATED ON THE CORRESPONDING END PORTION OF SAID BOLSTER AND ITS UPPER END SUPPORTING THE CORRESPONDING FRAME BRACKET, MEANS CONNECTING EACH END OF EACH WALKING BEAM TO A CORRESPONDING AXLE END IN A VERTICAL PLANE BETWEEN SAID FRAME AND WHEELS, AND GUIDE MEANS OPERATIVELY INTERPOSED BETWEEN SAID FRAME AND BOLSTER AND CONSTRAINING SAID FRAME TO MOVE IN A SUBSTANTIALLY VERTICAL PATH.