Adjustable bulldozer blade mounting

Claim 1

A MOUNTING FOR ATTACHING A BLADE TO A TRACTOR COMPRISING: A PAIR OF SPACED APART PUSH ARMS EACH PIVOTALLY MOUNTED AT A POINT INTERMEDIATE ITS END ON SAID TRACTOR, SAID BLADE BEING PIVOTALLY ATTACHED TO THE FORWARD ENDS OF SAID ARMS; A PAIR OF DOUBLE-ACTING LIFT CYLINDERS OF EQUAL CAPACITY PIVOTALLY ATTACHED TO SAID TRACTOR AND TO THE REARWARD ENDS OF SAID PUSH ARMS; A BOUDBLE-ACTING TILT CYLINDER MEANS PIVOTALLY MOUNTED ON ONE OF SAID PUSH ARMS AND PIVOTALLY SECURED TO SAID BLADE; AN ADJUSTABLE JACK MEANS INCLUDED IN SAID TILT CYLINDER MEANS BETWEEN SAID BLADE AND SAID PUSH ARMS; AN ADJUSTABLE TILT BRACE PIVOTALLY SECURED TO THE OTHER OF SAID PUSH ARMS AND TO SAID BLADE FLUID CIRCUIT MEANS INCLUDING A FLUID PRESSURE SOURCE AND A CONTROL VALVE HYDRAULICALLY CONNECTED TO THE ROD AND HEAD ENDS OF EACH OF SAID LIFT CYLINDERS AND TO THE ROD AND HEAD END OF SAID TILT CYLINDERS MEANS WHEREBY UPON SELECTIVE MOVEMENT OF SAID CONTROL VALVE SAID BLADE IS RAISED AND LOWERED AND SAID BLADE IS TILTED; FIRST CONDUIT MEANS INTERCONNECTING THE ROD ENDS OF EACH OF SAID LIFT CYLINDERS; AND SECOND CONDUIT MEANS INTERCONNECTING THE HEAD ENDS OF EACH OF SAID LIFT CYLINDERS WHEREBY WHEN SAID TILT CYLINDER MEANS IS ACTUATED SAID PUSH ARMS CAN PIVOT IN OPPOSITE DIRECTIONS IN RESPONSE TO THE FORCES SET UP IN SAID LIFT CYLINDERS TO RELIEVE THE STRESSES CREATED BY THE TILTING OF SAID BLADE.