MAST MAINTENANCE
The mast sections run on maintenance free
rollers, and on the outer mast surface where
the roller runs, a brush is fitted to keep the
mast surface clean, preventing debris picking
up in the roller. In addition to these rollers,
there are six external plastic screws fitted,
which act to hold the mast sections together
in torsion. These screws are fitted with M24
lock nuts and can easily be identified at the
lower end of the mast sections. Inside the
mast there are additional wear pads and
rollers, which can be accessed from the top
of the mast. These items are not adjustable,
and it is very unlikely that any wear will occur.
The mast is raised and lowered with a
multistage hydraulic piston, which raises
the outer mast section first, followed by
the middle mast section. When the mast is
lowered, the sections close in the reverse
sequence i.e. the middle section and outer
section close together until the bottom of
the middle section contacts the lower rest
buffers, and the outer section continues to
close over the middle section. It is essential
the mast closes in this sequence.
To ensure the mast sections move in the
correct sequence, and do not bind, ensure
the wear screws are not over tightened
as follows: Ensure the gap between the
overlapping mast section and the inner mast
section is even on both sides. The distance is
approximately 12mm, but may vary slightly
due to manufacturing tolerances.
Loosen the wear screw lock nut and turn the
screw until it just contacts the inner mast
surface. Do not force the screw. Tighten the
locknut using caution not to shear the screw
thread. Raise and lower the mast to check it
does not bind.
In practice, it is far more likely that the
screws may wear so an excessive gap
between the mast section and the wear
screw develops. This will be evident by free
sideways movement of the basket. If this free
movement is thought to be excessive, check
the gap between the screw and the mast
with a feeler gauge. The correct gap should
be no more than 0.2mm, although the mast
is serviceable with a gap up to 0.5mm.
TILT SWITCH CHECK
Pre-operation check; Elevate platform a small
distance and drive machine down or up a
gentle slope of around 3 degrees. Machine
should stop travelling and alarm sound.
To check the correct operation of the tilt
switch raise the platform from the transport
position a small distance (e.g.50mm) on truly
level ground. Position a suitable lever under
one side of the platform and raise this side
of the machine from the ground. The tilt
switch should operate when the drive wheel
is approximately 25 - 30mm from the ground.
This should really be repeated from both
sides of the machine to compensate for out
of level ground...i.e. you might have 20mm
one side and 40mm the other side.
When the platform is in the transport
position i.e. fully closed the alarm and cut
out should not operate when the above
test is repeated. If the cut out and alarm
does operate when in the transport position
then it is most likely the limit switch is not
adjusted correctly or is faulty.
The limit switch and wiring are installed so
that in a failure mode condition the system
will operate in the safe condition only i.e. tilt
switch operates and cuts out lift when out of
level tolerance exceeded.
PLATFORM LOAD SENSING CHECK
With the platform in the retracted position,
place 200kgs in the platform. Elevate the
platform from the ground controls so the
platform floor is approximately 2.0M from
the ground. The addition of a small extra load
should operate the alarm (there is a small
delay from switching to alarm sounding),
although the tolerance is up to 40 kgs
additional load.
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MAINTENANCE PROCEDURES
