Doosan DCT9PS Operación Y Mantenimiento página 56

ASSEMBLY OF THE DCT25BV AND DCT25BS PAVING BREAKERS
GENERAL INSTRUCTIONS
• Before assembly of the pickhammer, clean all parts
thoroughly and lubricate surfaces with a thin film of
recommended oil (see Lubrication).
• Apply a film of O-ring lubricant to all O-rings before final
assembly.
• It is recommended that the assembling of the nozzle (2) be
carried out by the manufacturer or authorised distributor.
• The existence of a piston air cushion should be determined.
Hold the cylinder vertically and allow the piston to drop
down the bore small diameter first. An air cushion is
present if the piston "bounces" at the bottom of the cylinder
and no metal to metal contact noise can be heard. If a
cushion is not present contact your authorised Doosan
Benelux SA repair centre for advice.
CYLINDER ASSEMBLY
Grip the cylinder (1) vertically in a vice protected with leather
or copper covered vice jaws.
Lubricate and insert the piston (3) small end first into the bore.
– Check for air cushion.
Lubricate and slide the valve ring (4) onto the cylinder and
replace valve plate (5).
Replace the spacing washer (6) on top of the valve plate.
HANDLE ASSEMBLY
Position trigger (25) in its slot in the handle body and align the
holes in each part.
Drift or press home the trigger pin (26). Check the throttle lever
is free to move easily.
Grip the handle body (24) in a vice protected with leather or
copper covered vice jaws.
Lubricate and insert throttle pin (32) into position reduced
diameter out of the hole.
Replace the throttle ball (27) and throttle spring (28) and retain
in place with throttle valve plug (29), apply Loctite 243 to the
threads of the plug and screw home fully.
If the air inlet (30) has been removed, refit it into the handle
body using Loctite 243 and screw home fully.
Replace the quick release coupling (31).
MAIN DISASSEMBLY
Firmly grip the cylinder assembly vertically across the flats,
in a vice protected with leather or copper covered vice jaws.
Check for correct location of the valve ring (4) valve plate (5)
and spacing washer (6).
Carefully lower the handle assembly (23) onto the cylinder and
engage the threads. Tighten the handle down by hand.
Fully tighten the handle using the 1.5 meters long pipe until the
lock pin (7) can be replaced in position – thread to the out side.
Slide the muffler (9) down the cylinder until the muffler
retaining lip engages with the groove in the cylinder. Replace
the retaining clip (10) in its groove in the cylinder (DCT9PS
only).
ASSEMBLY OF THE FRONTHEAD –
SCREW RETAINER MODELS
Replace the sealing ring (8) in its groove in the cylinder.
Inspect the chisel buffer (13) for wear and replace if necessary,
by sliding a new buffer into the retainer.
Screw the retainer onto the cylinder assembly.
ASSEMBLY OF THE FRONTHEAD –
LATCH RETAINER MODELS
Grease the latch plunger (22) and plunger spring (21) and
insert them into position in the fronthead (15).
Locate the latch lever (20) with the holes in the front head and
press or drift into place the fronthead spring pins (18,19).
Check the operation of the latch.
Slide the fronthead (15) onto the end of the cylinder and align
the bolt hole with the groove machined in the cylinder.
Fit fronthead screw (16) and secure with front head nut (17)
tighten to 90 Nm (66.4 lbs.ft) torque.
ASSEMBLY CHECKS
Following service or repair the pickhammer should be checked
for correct operation before being sent back to the job site.
Fit the correct size accessory into the pickhammer and
connect to an airline. Using low pressure 2 bar (30 psi), check
to ensure the pickhammer is free from air leaks around the inlet
connection and that the pickhammer does not automatically
start to operate without the trigger being depressed.
Increase the air pressure to 6 bar (90 psi) and run the tool in
short bursts to check the tools starts and stops cleanly and
without hesitation.
Pickhammer operating frequency should be as given in the
specification table at the end of this manual.
56