Pivot pin structure

Claim 1

IN AN EARTH MOVING PIECE OF EQUIPMENT FOR A TRACTOR HAVING A PAIR OF SUPPORTING FRAMES ON OPPOSITE SIDES OF THE TRACTOR, A PAIR OF FORWARDLY EXTENDING LIFT ARMS EXTENDING FROM THE SUPPORTING FRAMES, AND MEANS INTERCONNECTING THE ARMS, THE IMPROVEMENT COMPRISING: A PAIR OF HORIZONTALLY DISPOSED AND ALINED PIVOT PINS, EACH OF SAID PINS HAVING OPPOSITE ECCENTRIC END PORTIONS WITH ONE END PORTION EXTENDING THROUGH ONE OF THE UPRIGHT FRAMES AND THE OPPOSITE END PORTION EXTENDING THROUGH A RESPECTIVE LIFT ARM FOR PERMITTING VERTICAL MOVEMENT OF THE ARM; A PAIR OF TAPPED OPENINGS EXTENDING AXIALLY THROUGH SAID ONE END PORTION OF EACH OF THE PIVOT PINS, THE TAPPED OPENINGS BEING ON A DIAMETER OF THE RESPECTIVE END PORTION AND EQUAL DISTANCE FROM ITS AXIS; PLATES LYING ADJACENT THE LATTER END PORTIONS AND OVERLYING PARTIALLY THE RESPECTIVE SUPPORTING FRAMES, SAID PLATES HAVING ALINED OPENINGS WITH THE TAPPED OPENINGS OF THE RESPECTIVE END PORTIONS AND LUG RECEIVING NOTCHES; THREADED ELEMENTS EXTENDING THROUGH THE LATTER OPENINGS AND THREADEDLY RECEIVED IN THE TAPPED OPENINGS; AND LUGS ON THE RESPECTIVE SUPPORTING FRAMES CONTACTING THE NOTCHES OF THE RESPECTIVE PLATES FOR PREVENTING ROTATION OF THE RESPECTIVE PINS.