Hitch assembly

A ground-working tool for attachment to a towing vehicle, comprising:

• a first longitudinal hitch frame having a front end adapted for connection to the towing vehicle, and a rear end;
• a second longitudinal hitch frame;
• hinge means mounting the rear end of the first longitudinal hitch frame to the second hitch frame for relative pivotal movement about a horizontal transverse axis;
• a ground-working implement operatively mounted to the second hitch frame;
• lift means on the second hitch frame for moving the ground-working implement between an elevated inoperative position above the ground-working surface and an operative position engaging the ground, comprised of a ground-engaging wheel and hydraulic cylinder means on the second hitch frame, mounting the wheel to the second hitch frame and selectively operable to raise and lower the second hitch frame and attached implement between the operative and inoperative positions;
• control means operably connected with the hydraulic cylinder means to operate in conjunction with operation of the hydraulic cylinder means for alternately operating to (a) lock the first and second hitch frames together when the ground-working implement is in the elevated inoperative position;
• (b) tip the second hitch frame and ground-working implement downward and forwardly as the support means is operated to move the ground-working implement to its operative position engaging the ground;
• and (c) permit pivotal movement between the hitch frames relative to one another about the hinge axis after the ground-working implement has been moved to its operative position;
• wherein the control means includes (a) a linkage pivotally interconnected between the first and second hitch frames;
• and (b) a hydraulic linkage cylinder having opposed ends operatively connected to the linkage, said hydraulic linkage cylinder being operatively connected to the hydraulic cylinder means on the second hitch frame to lock the hitch frame together when the hydraulic cylinder means has been operated to raise the implement and second hitch frame to the operative position, and to unlock the hitch frames for relative pivotal movement about the hinge axis;
• biasing means responsive to movement of the hydraulic linkage cylinder and attached linkage to unlock the first and second hitch frames, for urging the second hitch frame and the ground-working implement to tip downwardly as the hydraulic linkage cylinder is operated to unlock the hitch frames;
• and
• restrictor means between the hydraulic cylinder means of the lift and the hydraulic linkage cylinder of the control means for causing operation of the hydraulic linkage cylinder to unlock the frame before the hydraulic cylinder means is operated to lower the second hitch frame.

An attachment for a ground-working tool having a wheel supported frame and a hydraulic lift for raising or lowering the frame relative to the ground surface, the frame including an elongated longitudinal tongue extending forwardly to an end for attachment to a towing vehicle, said attachment comprising:

• hinge means adapted to divide the tongue into a first hitch frame and a second hitch frame and to join the frames together about a transverse hinge axis;
• control means adapted to operably interconnect the first and second hitch frames and to alternately (a) lock the first and second hitch frames to one another, and (b) tip the second hitch frame downwardly and forwardly relative to the first hitch frame, or (c) permit pivotal movement between the first and second frames relative to one another about the transverse hinge axis;
• wheels adapted to movably hold the first hitch frame at a selected elevation;
• suspension means adapted to be mounted between the wheels and first hitch frame for mounting the wheels to the first hitch frame for pivotal movement about a longitudinal axis;
• and
• height adjustment means adapted to fit between the suspension means and first hitch frame for adjusting the elevation of the first hitch frame.