초록 ▼

Hydraulic lift cylinders on a transversely extending implement frame, such as a multi-section hinged implement, are connected by valve and conduit structure to operate as single acting cylinders in parallel during an automatic depth control mode for individual cylinder control. An operator control v

Hydraulic lift cylinders on a transversely extending implement frame, such as a multi-section hinged implement, are connected by valve and conduit structure to operate as single acting cylinders in parallel during an automatic depth control mode for individual cylinder control. An operator control valve and depth sensing valve permit the operator to change to a fast raise/fast lower mode wherein flow control structure causes the lift cylinders to operate substantially in series for raising and lowering the implement in level fashion across its width to and from a transport position.

대표청구항 ▼

In an argricultural implement having a transversely extending frame supporting earthworking tools, and at least first and second cylinders connected to lift structures for raising and lowering the frame between ground-working and transport positions and for controlling soil penetration of the tools

In an argricultural implement having a transversely extending frame supporting earthworking tools, and at least first and second cylinders connected to lift structures for raising and lowering the frame between ground-working and transport positions and for controlling soil penetration of the tools when the frame is in the ground-working position, a cylinder control system comprising: automatic depth control means for operating the cylinders in an automatic depth control mode when the frame is in the ground-working position; flow control means connected to the cylinders for constraining the cylinders to operate substantially in series as the frame is raised toward the transport position so that the frame raises uniformly across its width and permitting the cylinders to operate substantially in parallel in the automatic depth control mode, said flow control means including pressure responsive check valve means connected between the automatic depth control means and the first cylinder for automatically directing fluid flow from the first cylinder to the second cylinder as the frame is raised toward the transport position, and from the first cylinder away from the second cylinder when operating in the depth control mode.