Gravely 950001, Maintenance Manual

Page: 53 / 66

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Trencher Connections “A” & “C”
Connection “A” must be used to power the trencher
motor, note this is a female coupling to avoid incorrect
connection with “C” or “B”.
These are male couplings. The “C” coupling is the
“Return” oil from the trencher motor, connections “A”
and “C” must be connected to the trencher for the
trencher to function properly.
Connections “A” & “B”
Connections “A” & “B” are used in combination for all
other PTO optional equipment attachments, such as
post hole digger, rotary broom and rippers, etc.
Trencher Valve Operation
Sequence Valve Item 5 is set @ 150 bar. (2200 psi).
This is the pressure above which wheel drive speed will
start to decrease. Needle valve Item 2 is operator
controlled. It sets the maximum wheel drive speed
when the trencher drive is engaged. This adjustment is
normally set before trench digging commences. The
setting of Item 2 would normally be above the travel
speed that you want to trench at because trenching
speed will be limited to the speed setting if digging in
very easy soft ground. When using any other PTO
drives on “A” and “B” couplings, be sure to leave this
adjustment fully “closed” (turn clockwise), or else full
flow will not be available in one direction.
Sequence valve Item 1 is set @ 103 bar. (1500 psi), i.e.
below the main relief valve setting. This should not
need to be adjusted as it only functions in the trencher
mode when reversing the trencher chain. It will put a
103 bar. (1500 psi) artificial load on the reverse drive of
the trencher chain. This will not limit the maximum
torque available on the trencher for reverse drive.
When using other PTO functions on “A” & “B”
couplings, valve Item 5 makes it possible to still get 210
bar. (3000 psi) from coupling “B”, because its outlet is
now effectively blocked by counterbalance valve Item 4
and quick coupler “C”.
C
A
B
5
a b
T
1
CIRCUIT SEGMENT