1. (e) Use a suction pump to remove the oil from the
reservoir.
(f) Remove the lifting arms from the carriage and
remove the bottom limit switch cover.
2. (a) Drive column dismantling:
Label all the cables that run up inside the upright
(motor, proximity, overhead limit switch, top limit
switch). Disconnect them from the terminals in the
control box and remove from the cable glands and
upright (electrician required).
(b) Slave column dismantling:
Disconnect the slave proximity cable from the
terminals in the drive column control box and
remove the cable from the cable gland and
overhead cross beam and uprights (electrician
required).
Disconnect the cables from the slave motor and
slave top limit switch.
3. (a) Rig up a safe method of supporting the
overhead cross beam so the upright may be
removed.
This can be done by hanging a rope from the roof to
the cross beam or by using a scaffold or an “A”
frame.
(b) unbolt the upright from the cross beam then
from the column.
(c) Remove the bolts securing the base plate of the
column to the base frame.
4. (a)Tilt the column forward and lower it gently to rest
on a suitable support approx. 250 mm high on the
floor.
(b) Place more suitable 250 mm high supports
beside the column then roll the column over onto its
back.
5. (a) At the base of the column, remove the Nyloc nut
and withdraw the collar from the screw. Remove
the key.
(b) Undo the two cap screws that hold the bottom
bearing housing and reservoir in place.
6. (a) At the top of the column, undo the proximity
switch and remove the cable from under the clip.
Push the proximity switch into the hole in the top
plate.
(b) Remove the four nuts securing the top plate to
the column (the large pulley may be left in place).
Withdraw the top plate and screw assembly a
distance of approximately 500 mm and place a
support under the screw inside the top of the
column.
7. (a) Slide the bottom bearing housing off the
bottom of the screw.
(b) Unscrew the lift screw out of the lift and safety
nuts in the carriage. Take care not to damage the
screw thread or sealing surfaces.
(c) Remove the two nuts and the nylon load ring
from the carriage
(d) Roll the carriage up and out of the top of the
column.
Inspection Procedure
Lift Screw
Thoroughly wash the screw to remove all dirty oil.
Inspect the outside diameter and top and bottom flanks
of the thread for any signs of scoring or uneven wear.
Note: The major diameter may have small intermittent
grooves in its outside diameter which are produced
during manufacture.
Inspect the bottom sealing surface for damage where
the oil seal runs. Polish out any small scratches with
400 grit emery paper. Inspect the bearing areas and
keyway for signs of wear.
Lift nut
Wash thoroughly to remove all oil. Inspect the flanks of
the thread for signs of scoring or uneven wear. If it is
scored, also check the lift screw and safety nut. Inspect
the thread minor diameter. When new, it is 2.0 mm
thick. If it is worn to less than 0.5 mm thick, the nut
must be replaced. Check that the trigger moves freely
and the spring loaded pin slides.
Safety nuts
Wash the safety nut to remove all oil. Inspect the flanks
of the thread for signs of scoring or wear. Check the
thread minor diameter. When new it is 1.5 mm thick. If
it is worn to less than 1.0 mm thick, the nut must be
replaced.
Carriage
Pull the top of the catch bar, at the back of the carriage,
10 mm away from its stop and release it - it must return
to its stop without sticking. Look through the hole in the
catch bar pivot pin (Item 49 in the parts list). The pin
should not be deformed at all - if it is deformed, it must
be replaced. Lubricate the pivot pin and spring guide.
Inspect the four plastic slide pads for wear. There
should be no more than 1 mm wear on the pads.
Check the M8 cap screws are tight. Remove and
inspect the bearings in the carriage rollers. The
bearings consist of a layer of bronze particles covered
by a layer of Teflon. If the bearing appears to be mostly
bronze coloured, it requires replacement; if it is mostly
grey/green coloured, it is still in good condition. Do not
polish off the grey/ green colour on the roller pin unless
the pin is scored. Polish only with 400 grit emery paper
and replace the mating bearing at the same time.
Lightly grease the roller pin, bearing, roller slides and
thrust washers when refitting. Make sure the circlips
are fully seated in their grooves.
Bottom bearing
Pull the reservoir tube off the bearing housing. Remove
the O-ring, bearing and oil seal. Wash all parts
thoroughly. Inspect the bearings for any signs of pitting
or wear on the balls and raceways. Fit a new seal and
O-ring. Repack the bearing with grease and refit.
Wrap in plastic to keep clean.
Page 9
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