DECKMASTER
4.2
Levelwind Drive
The open loop circuit for the levelwind drive employs a fixed displacement gear pump. Hydraulic oil is drawn
from the reservoir through the suction strainer (1B) to the gear pump (6). The pump pressure is monitored by the
pressure gauges (7B) on the hydraulic unit and at the levelwind valve. Circuit protection is provided by the relief valve
(8).
The flow from the pump is directed to the valve (26) for the levelwind. This is a pressure compensated, four
way, three position, directional control valve. The tandem center of the valve blocks the A and B work ports to the
levelwind motor (27) when the valve is in the neutral position. When the valve spool is shifted the flow is directed to the
motor. The spool is spring centered to return to the neutral position when the handle is released. The exhaust flow from
the levelwind circuit returns to the reservoir through the return filter (1C).
A dual relief valve (16) is provided to protect the levelwind motor and structure from overloads. Also, the ball
valve (21) can be opened to allow freewheeling of the motor and movement of the levelwind head without hydraulic
pressure.
4-7 *
