MR & MRS OPERATION TABLES
Page 28 of 29 T-SM5f
4.57 To replace leg section release bar follow the
procedure detailed above for the head section
handle but replace with a new leg section release
bar.
Replacing gas spring unit - head / leg section
Note: See WARNINGS and CAUTIONS above
section 4.21 and serial number details in section
4.23.
4.58 To replace a head or leg section gas spring
the procedure is basically the same as detailed
below for a head section gas spring. Proceed as
follows:
i Refer to Fig. 19 and unscrew gas spring nut
from link (10) at piston end. Then remove
pivot pin circlips (21) and release grub screw
(32) if fitted from the hinge block (24 or 26)
supporting the cylinder end of gas spring
(9).
ii Tap out the pivot pin (28). Remove gas
spring unit (9) by unscrewing it from link
(10) and replace with a new one, noting
warning above and do not lubricate.
iii Fit new unit by reversing the removal
procedure and adjust gas spring nut to obtain
a 1.0mm gap between gas spring plunger
and release handle (or release bar). Refit
section on table and check for correct
operation.
Control arm gas spring replacement - MRS
table Serial Number 1024 or later
4.59 To replace the control arm gas spring
proceed as follows but note the WARNING and
CAUTION in section 4.21:
i Remove the head end extended control arm
bottom cover as shown in Fig. 20.
ii Refer to Fig. 20 and remove the circlip (1)
on the pivot pin (2) of the gas spring (4) and
loosen the locking nut (3) on the end of the
gas springs piston.
CAUTION
The control arm will require support
when the pivot pin is removed
iii Remove the pivot pin (2) from the end of the gas
spring (3) and unscrew the gas spring piston.
iv Replace the gas spring with a new unit by the
reverse of the above.
v Adjust the gas spring by rotating the piston until
the release pin just touches the face of the pistol
grip release lever. Lock in place with the lock
nut and check operation. Finally replace cover
and ensure correct operation of control arm.
HYDRAULIC SYSTEM OPERATION
NOTES (Fig. 21)
4.60 The following description is to give the user
an appreciation of what happens within the
hydraulic system during operation of the pump
pedal to raise and lower the table top. It should be
read in conjunction with section 4.29 and 4.30
when making adjustments to the setting of the ram
release mechanism.
4.61 The hydraulic flow sequence, illustrated in
Fig. 21 can be followed by referring to diagrams
A, B and C.
A. Pump pedal up-stroke. Oil is drawn from
sump into piston chamber (3) via the small
ball valve (7) which is lifted from its seat.
B. Pump pedal down-stroke (using normal foot
pressure). Oil under pressure from piston
chamber (3) closes small ball-valve (7) but
opens large ball-valve (8) and pilot valve
(9), allowing pressurised oil to reach the ram
chamber (6).
C. Pump pedal pushed fully down. Piston (2)
contacts release plunger (10) to operate ram
release lever (11) which opens both small
and large ball-valves (7) and (8). Oil from
ram chamber (6) then flows at a controlled
rate back to the sump via inner bore of pilot
valve while the pilot valve is seated.
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