Dual-pump, flow-isolated hydraulic circuit for an agricultural tractor

In combination, (a) a tractor, (b) a planter towed by the tractor and including a planting mechanism powered by a rotary hydraulic motor and at least one lateral wing extension powered by a hydraulic cylinder, and (c) a hydraulic circuit for the tractor, and wherein the circuit includes:

• a valve assembly having a manifold block with first and second valves fitted therein;
• and wherein the manifold block further includes:
• a first feed path connected to the first valve and a second feed path flow-isolated from the first feed path and connected to the second valve;
• a first return path connected to the first valve and a second return path flow-isolated from the first return path and connected to the second valve;
• and wherein the circuit further includes:
• a fixed displacement pump flowing fluid to the first feed path;
• and
• a variable displacement pump flowing fluid to the second feed path;
• and wherein:
• the first valve is connected to the hydraulic cylinder and the second valve is connected to the motor.

In combination, (a) a tractor, (b) a planter towed by the tractor and including a planting mechanism powered by a rotary hydraulic motor and at least one lateral wing extension powered by a hydraulic cylinder, and (c) a hydraulic circuit for the tractor, and wherein the circuit includes a power steering system and further includes:

• a valve assembly mounted on the tractor and having a manifold block with first and second valves fitted therein;
• and wherein the manifold block further includes:
• a first feed path connected to the first valve and a second feed path flow-isolated from the first feed path and connected to the second valve;
• a first return path connected to the first valve and a second return path flow-isolated from the first return path and connected to the second valve;
• and wherein the circuit further includes:
• a fixed displacement pump flowing fluid to the first feed path;
• and
• a variable displacement pump flowing fluid to the second feed path;
• and wherein:
• the first pump is connected to the power steering system through a priority valve;
• the first pump flows fluid to the power steering system and to the first feed path;
• the first valve is connected to the hydraulic cylinder and the second valve is connected to the motor.