Automatically counterbalanced tractor side-boom crane

Claim 1

A SIDE-BOOM CRANE FOR A TRACTOR HAVING A MAIN FRAME DIRIGIBLY SUPPORTED AND POWERED FOR TRANSLATION IN A GENERALLY-HORIZONTAL ATTITUDE AND AN HYDRAULIC PRESSURE SYSTEM, COMPRISING A RIGID YOKE ASSEMBLY LATERALLY AND UPWARDLY SPANNING THE TRACTOR IN FIXED ATTACHMENT AT ITS LOWER ENDS TO OPPOSITE SIDES OF SAID FRAME, A BOOM ENDHINGED TO ONE SIDE OF SAID YOKE FOR VERTICAL OSCILLATION IN A PLANE TRANSVERSE OF THE TRACTOR, WINCH MEANS CARRIED AT THE SIDE OF SAID YOKE REMOTE FROM THE BOOM IN POWERED RELATION WITH THE HYDRAULIC SYSTEM OF THE TRACTOR SELECTIVELY ACTUABLE TO ANGULARLY ADJUST SAID BOOM THROUGH ITS RANGE OF OSCILLATION, COUNTERWEIGHT MEANS PIVOTALLY MOUNTED TO SAID YOKE AT THE SAME SIDE OF SAID YOKE AS WINCH MEANS, A FIRST SHEAVE MEANS ON SAID COUNTERWEIGHT MEANS, A SECOND SHEAVE MEANS MOUNTED ON SAID YOKE INWARDLY OF SAID COUNTERWEIGHT PIVOT, AND CABLE MEANS CONNECTED TO SAID BOOM PASSING OVER SAID FIRST SHEAVE MEANS, THENCE OVER SAID SECOND SHEAVE MEANS TO SAID WINCH MEANS, WHEREBY LOADS APPLIED LATERALLY OF THE TRACTOR BY SAID BOOM ARE AUTOMATICALLY COUNTERBALANCED.