Spearhead TWIGA
120
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Performance & Working Geometry
The ‘swingover’ feature allows it to be operated on both sides of the tractor without any re-
building or operator adjustments. However, to achieve the best cutting action the cutterbar
mounting is designed to pitch the knife downwards at eight degrees.
This is maintained throughout the operating range except when the cutterbar is pointing
upwards during operations on the left hand side. In these positions the knife has to operate
with its back to the hedge and therefore some deterioration in the quality of cut can be
expected. If it is necessary to carry out a considerable amount of work in these positions
the topping performance can be improved by shortening the top link, this will tilt the
machine forward thus altering the approach angle of the cutterbar. The geometry also
results in considerably less reach being available for ground cutting on the left hand side.
In addition, be aware that the geometry, depending on the length of draft links and the size
of the tractor's wheels may allow the cutterbar to foul the tractor tyres; therefore extra care
should be taken when positioning the cutterbar for ‘close in’ ground cuts. Also check
carefully that there is clearance between the arms and the tractor's roll bar/cab before
executing the 'swing over' maneuver, The operation of the arms takes priority on the oil
flow and will cause the knife to slow down during arm movements. If cutting material which
is towards the limit of the Excel 120’s capabilities avoid making arm adjustments while
cutting is taking place as there is a likelihood, that the knife will stall.
Swingover Prevention Mechanism
During normal arm movements to either side of
the tractor a safety mechanism is employed to
prevent the machine from accidentally
swinging over to the opposing work side when
operating the arms in raised positions.
Swingover Procedure
To swingover the machine for work on the
opposing side ‘reach out’ should be fully
operated to its furthest point then ‘lift up’ to
raise the arms into the upright position, by
operating angle the cutterbar can be turned to
the opposing side – the transfer of weight and
operation of ‘lift down’ will now permit working
on the opposing side.
Wherever possible the swingover procedure should be performed on level ground – if
swinging over on sloping ground is absolutely unavoidable always carry out the maneuver
with the tractor facing directly up the slope.
WARNING: Never attempt the swingover procedure when facing either across or
down a slope.
