OUO6030,0000461 -19-05APR04-1/2

A-Hydraulic Lock-up Valve
B-Pressure Reduction Valve

C-Center Frame (Master) Cylinder

D-Wing (Slave) Cylinder
E-Outer (Slave) Cylinder

F-Bypass Valve

Hydraulic lock-up valve (A) is closed when the cylinders are extended to hold machine in raised position for service and press wheels in retracted position for transport.

Pressure reduction valve (B) limits available pressure regardless of tractor model preventing flow over bypass valves (F). Mechanically set depth adjustment plates determine opener penetration and seed depth.

The center frame (master) cylinders (C), wing (slave 1) cylinders (D) and outer (slave 2) cylinders (E)-5-section only are in series with each other with the left side cylinders and right side cylinders parallel to the opposite side.

As hydraulic oil is pumped into base ends of master cylinders, oil is forced out the rod ends into base ends of slave 1 cylinders. Displaced oil in rod ends of the slave 1 cylinders returns to the tractor. On 5-section machines oil duplicates process from slave 1 through slave 2 cylinders before returning to tractor.

To compensate for smaller oil volume in rod ends of master cylinders, slave 1 cylinders are 6.4 mm (1/4 in.) smaller in diameter than the master cylinders and slave 2 cylinders are 6.4 mm (1/4 in.) smaller in diameter than slave 1 cylinders.

Master cylinders are tied together mechanically at rockshaft ensuring that uniform movement occurs on each side of the circuit. As the machine is raised and cylinders completely extend, slave 1 cylinders become synchronized with the master cylinders. Slave 2 cylinders become synchronized with slave 1 cylinders on 5-section machines.

As lift cylinders are retracted and encounter a mechanical stop (set by depth adjustment plates), pressure builds up on rod end of affected cylinder until the preset pressure of the bypass valve (F) is reached. At preset pressure, bypass valve will open, allowing oil to bypass the cylinder so remaining cylinders in the circuit reach mechanical stops as well. An orifice in each valve restricts oil flow to protect valve and reduce impact against stop.

Pressure reduction valve limits available pressure and preset relief pressure allows oil to flow over one or two bypass valves on each side of a 5-section machine and over only one valve on each side of a 3-section machine. Oil will flow through system only as required to ensure all cylinders contact stops.

OUO6030,0000461 -19-05APR04-2/2