Great Plains P13306 - Manual (Page 32)

Solo
Operating Instructions
32
5. Servicing and Maintenance
5.8 Hydraulics
A low oil flow should be used, i.e.,
tractor tickover or low flow
selected.
The wing circuit is controlled by an
overcentre valve contained within
the manifold block which positively
locks oil flow until pressurised by
the tractor. System pressure can
be retained in the circuit even after
depressurisation of the tractor
quick release couplings.
Exercise extreme care when
checking the valve or circuits, and
under no circumstances attempt
to adjust or loosen fittings without
prior reference to your authorised
simba dealer, and detailed
maintenance instructions.
5.9 Pro-Lift Trip-Reset Tine
Hydraulics
The circuit allows for the tines to be
pressurised down into work, whereupon a
relief valve limits this applied tractor down
pressure to a value less than the main system
accumulator (80b x 2 litre). This allows tines
to trip in work, the oil being absorbed by the
main accumulator. A secondary (rod side)
accumulator ensures this side of the cylinder
is maintained full of oil to minimise cavitation
and seal damage. A pre charge valve restricts
return rod side oil flow to the tractor as the
tines are pressurised down to ensure this
secondary circuit is charged.
In operation, oil is locked in the cylinder circuit
at a pressure determined by the relief valves
90-120 bar full bore side and 20 to 60 bar
rod side. This occurs at all times, even with
the circuit in float at the tractor, provided the
tines are fully down. For extremely stony
conditions, adjust the valve to read 90 bar on
the gauge as the tines are pressured down.
For heavy soils with little stone where
compaction is present it is possible to
increase this pressure to 120 bar.
Fig. 5.06: Pro-Lift Tine Hydraulic Manifold