Plow attachment for tractor

Claim 1

IN COMBINATION WITH A TRACTOR HAVING POWER OPERATED LIFT MEANS THEREON, A DRAFT STRUCTURE PIVOTALLY MOUNTEL ON THE TRACTOR AND OPERATIVELY CONNECTED TO THE LIFT MEANS FOR VERTICAL SWINGING OF THE DRAFT STRUCTURE IN AN ARCUATE PATH, AN IMPLEMENT CONNECTED TO THE DRAFT STRUCTURE FOR VERTICAL SWINGING THEREWITH FROM AN OPERATING TO A TRANSPORT POSITION, TRANSVERSE HINGE MEANS IN THE CONNECTION BETWEEN THE IMPLEMENT AND THE DRAFT STRUCTURE ACCOMMONDATING LIMITED DOWNWARD PIVOTING OF THE IMPLEMENT RELATIVE THERETO, MEANS IN SAID CONNECTION FOR POSITIVELY LOCKING THE IMPLEMENT AGAINST PIVOTING RELATIVE TO THE DRAFT STRUCTURE DURING OPERATION OF THE IMPLEMENT, SAID POSITIVE LOCKING MEANS BEING YIELDABLE UNDER THE WEIGHT OF THE IMPLEMENT, AFTER A PREDETERMINED LIFTING OF THE DRAFT STRUCTURE, TO ACCOMMODATE SAID PIVOTING OF THE IMPLEMENT.