MTD 242-630-000 - Manual (Page 13)

HOW YOUR LOG SPLITTER OPERATES
Cylinder
h.
Cylinder
Pilot
Pressure
Line
Pump
Reservoir High Volume
Low Pressure
Gear Section
Low Volume
High Pressure
Gear Section
THE PUMP
A two-stage log splitter pump has one large and one
small gear section, using common inlet and outlet
ports. Below a preset pressure (called unloading pres­
sure) a check valve between the two gear sections
allows both flows to combine. Together, the two gear
sections create a large volume flow which produces
rapid cylinder movement under low load conditions.
Above unloading pressure, a pilot pressure line
(which simulates actual pressure at the cylinder) acti­
vates the unloading valve, which causes the flow to
bypass the large gear section and return to the pump
inlet area. The small gear section is now operating
alone, and will generate the higher pressure neces­
sary for the actual log splitting operation.
The original factory setting for the unloading valve is
designed to provide maximum flow while remaining
below engine stalling load. Note: Splitting capability
is not affected by the setting of the unloading
valve. Do not attempt to adjust or reset it without
a pressure gauge (should be performed by an
authorized service dealer only).
THE DIRECTIONAL VALVE AND CYLINDER
From the pump, oil flows to a four way, three position
directional valve. At the neutral position this valve
directs the flow back to the oil reservoir, bypassing
the cylinder. When the directional valve is directing
the flow to the back of the cylinder, the cylinder rod
extends quickly until it meets significant resistance.
Upon reaching unloading pressure, movement of the
shaft will slow but will continue forward. If the pres­
sure reaches a preset maximum (called relief valve
pressure) the relief valve, located within the direction­
al valve, will allow the flow to bypass the cylinder and
return to the reservoir. This can happen when the
cylinder rod meets excessive resistance, or when it
reaches the end of its stroke and can move no farther.
Note: Never operate at relief valve pressure for more
than a few seconds.
When the directional valve is directing the flow to the
front of the cylinder, the rod will retract quickly since it
is encountering no resistance. The relief valve will
momentarily bypass the flow at the end of the return
stroke but the directional valve should then automati­
cally return to the neutral position, directing the flow
directly into the reservoir. This serves to protect the
pump from possible damage due to prolonged opera­
tion at relief valve pressure.
Because of the potential for system damage, the relief
valve is carefully and precisely preset by the manu­
facturer.
Note: The user should not attempt to adjust or change
the setting of the relief valve.
OPERATIDNAL PRDBLEMS
If you have trouble with your log splitter, please refer
to the Hydraulic Trouble Shooting Guide on page 15.
Note: Readjustment of valves or disassembly of
pump should be performed by an authorized ser­
vice dealer only.
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