Rear mounted attachment with single acting cylinder

A tillage implement having a generally transversely extending main frame supported by lift wheel structure for forward movement over a field, the implement including tool structure for penetrating the ground, a trailing attachment for working the ground behind the tool structure comprising:

• first and second transversely spaced trailing support arms connected to the frame and extending rearwardly therefrom to aft ends;
• an attachment frame connected to the aft ends and including first and second fore-and-aft spaced transversely extending support members and trailing tools depending from the support members and engaging the ground behind the tool structure, the support members and trailing tools having a combined weight sufficient to provide down pressure for ground penetration of the trailing tools independently of additional down pressure structures;
• hydraulic lift structure including a single acting hydraulic cylinder having first and second ends and connected between the main frame and the support arms and operable to lift the trailing implement relative to the frame;
• a stop member preventing lowering of the attachment frame below a lowermost position;
• a control valve connected to a source of hydraulic fluid under pressure;
• a hydraulic line operably connecting the control valve to the first end of the cylinder;
• wherein the control valve has a first position to operate the cylinder to lift the trailing attachment to an uppermost position, a second position to allow the trailing attachment to lower under the influence of the combined weight toward the lowermost position, and a blocking position wherein hydraulic fluid flow is blocked from passing to and from the cylinder to generally maintain the attachment in a selected operating position relative to the frame, the selected operating position lying within a range from the lowermost position to an upper operating position below the uppermost position;
• and
• breather structure connected to the second end of the cylinder facilitating movement of fluid to and from the cylinder, wherein a pressure differential is established in the line to permit the attachment to lift relative to the main frame from the selected operating position when the valve is the blocking position and lift forces exceed down pressure forces on the attachment, so that forces transferred to the main frame from the attachment frame are limited when the implement is working the ground with the control valve in the blocking position.

A deep tillage implement having a generally transversely extending frame supporting shanks for penetrating the ground, a trailing attachment for working the ground behind the shanks comprising:

• trailing implement support arm structure connected to the frame and extending rearwardly therefrom to a connection with trailing attachment tools;
• hydraulic lift structure including a first single acting hydraulic cylinder having first and second ends connected between the frame and the support arm structure and operable to move the trailing implement vertically relative to the frame;
• a hydraulic control connected to a source of hydraulic fluid under pressure, a line connecting the hydraulic control to the first end, the control having a lift position to pressurize the first end and operate the cylinder to lift the trailing attachment, and a field operating position wherein hydraulic fluid flow is blocked from passing through the valve to the cylinder to lift the attachment;
• a breather connected to the second end of the cylinder facilitating movement of fluid to and from the second end when the cylinder retracts and extends, wherein a vacuum is drawn in the line to permit the attachment to lift relative to the frame when the valve is in the field operating position and lift forces exceed attachment weight, so that forces transferred to the frame from the attachment are limited when the implement is operating over depressions or when the depth of operation of the deep tillage implement increases;
• and
• wherein the support arm structure comprises a four bar linkage with upper and lower links and wherein the cylinder is located between the links.

A deep tillage implement having a generally transversely extending frame supporting shanks for penetrating the ground, a trailing attachment for working the ground behind the shanks comprising:

• trailing implement support arm structure connected to the frame and extending rearwardly therefrom to a connection with trailing attachment tools;
• hydraulic lift structure including a first single acting hydraulic cylinder having first and second ends connected between the frame and the support arm structure and operable to move the trailing implement vertically relative to the frame;
• a hydraulic control connected to a source of hydraulic fluid under pressure, a line connecting the hydraulic control to the first end, the control having a lift position to pressurize the first end and operate the cylinder to lift the trailing attachment, and a field operating position wherein hydraulic fluid flow is blocked from passing through the valve to the cylinder to lift the attachment;
• a breather connected to the second end of the cylinder facilitating movement of fluid to and from the second end when the cylinder retracts and extends, wherein a vacuum is drawn in the line to permit the attachment to lift relative to the frame when the valve is in the field operating position and lift forces exceed attachment weight, so that forces transferred to the frame from the attachment are limited when the implement is operating over depressions or when the depth of operation of the deep tillage implement increases;
• and
• wherein the support arm structure comprises two offset arms, the first cylinder connected to the first arm, and wherein the hydraulic lift structure includes a second cylinder connected to the second arm and in parallel with the first cylinder, the first and second cylinders facilitating differential movement of the two offset arms so angle of the trailing attachment about a generally fore and aft axis can change relative to the frame to follow ground contour.

A deep tillage implement having a generally transversely extending frame supporting shanks for penetrating the ground, a trailing attachment for working the ground behind the shanks comprising:

• trailing implement support arm structure connected to the frame and extending rearwardly therefrom to a connection with trailing attachment tools;
• hydraulic lift structure including a first single acting hydraulic cylinder having first and second ends connected between the frame and the support arm structure and operable to move the trailing implement vertically relative to the frame;
• a hydraulic control connected to a source of hydraulic fluid under pressure, a line connecting the hydraulic control to the first end, the control having a lift position to pressurize the first end and operate the cylinder to lift the trailing attachment, and a field operating position wherein hydraulic fluid flow is blocked from passing through the valve to the cylinder to lift the attachment;
• a breather connected to the second end of the cylinder facilitating movement of fluid to and from the second end when the cylinder retracts and extends, wherein a vacuum is drawn in the line to permit the attachment to lift relative to the frame when the valve is in the field operating position and lift forces exceed attachment weight, so that forces transferred to the frame from the attachment are limited when the implement is operating over depressions or when the depth of operation of the deep tillage implement increases;
• and
• further comprising a mechanical stop to limit movement of the attachment below a preselected lowermost level, and wherein the hydraulic control is operable to raise the attachment hydraulically above the lowermost level.