Agricultural apparatus having vertically adjustable disc gang assemblies

An agricultural frame apparatus comprising:

• a wheeled frame assembly adapted to be towed across a field, said frame assembly including at least two laterally spaced arms extending generally parallel to each other on opposite sides of the longitudinal centerline of and rearwardly from a hitch mechanism provided at a forward end of the frame assembly, and a series of laterally extending fore-and-aft spaced tool bars connected to each arm;
• a plurality of agricultural ground engaging tools mounted to said tool bars to form generally lateral rows of ground engaging tools;
• a first disc gang assembly connected toward a front end of and for generally vertical movement relative to the frame assembly, said first disc gang assembly being connected on one side of a longitudinal centerline of the frame assembly such that the assembly extends rearwardly and angularly away from the hitch mechanism;
• a second disc gang assembly connected toward the front end of and for generally vertical movement relative to the frame assembly, said second disc assembly being connected on a second side of the longitudinal centerline of the frame assembly such that the assembly extends rearwardly and angularly away from the hitch mechanism;
• disc gang assembly lifting assembly including a rock shaft extending generally parallel to said tool bars and having a fixed lateral axis of rotation extending to each side of the longitudinal centerline of the frame assembly, a plurality of crank arms extending radially from said rock shaft in angularly offset relation relative to each other and connected to said first and second disc gang assemblies, and a driver connected to one of said crank arms for rotating said shaft about said axis thereby conjointly elevating and positioning the first and second disc gang assembly relative to the frame assembly.