Maintenance And Repair; Follow Instructions; Dth Service; Disassembly - Atlas Copco Secoroc QLX Series Operator Instructions Manual

MAINTENANCE AND
REPAIR

Follow instructions

Along with correct operational technique; proper and timely
service and repair of a DTH hammer can extent component life
and reduce operational expenses considerably. The sections
following describe how to disassemble, inspect, repair and
reassemble all QLX hammers.
Depending on the degree to which you plan on servicing a DTH
hammer, a number of tools are required. The following lists the
tools needed for a complete overhaul of all QLX hammers. A
stand is required for holding the DTH hammer and it is presumed
that backhead and chuck threads have been loosened. Complete
overhaul includes measuring and inspecting all clearances at
seal locations and other wear points.
DTH hammer service
In most cases a DTH hammer will only require servicing when
the casing wears out or when performance deteriorates due
to internal parts wear. The level of inspection can obviously
be much less if the casing only needs replacement. If the DTH
hammer has lost performance a more detailed inspection will be
required.

Disassembly

The following disassembly procedure starts with the
presumption that the chuck and backhead threads have
been loosened. While the disassembly process is similar for all
QLX drills there are slight distinctions from one model to another
that will be noted.
Note: The QLX piston can be removed from either end of the drill.
QLX 40 piston can ONLY be removed from chuck end.
1. Mark the casing so you can note which end is the backhead
side and which is the chuck end. Once the hammer has been
disassembled it´s hard to tell which end is which.
Note: On QLX 50/55 and QLX 60/65, the casing is reversable
2. Loosen the chuck along with bit and retaining rings and
remove from casing.
3. Remove retaining rings and o-ring from bit shank.
4. Remove the chuck from the bit.
5. Remove the backhead from the other end of the casing.
The compression cone, check seal, guide, and valve assembly
will come out with the backhead. If the backhead is removed
before unseating the compression cone use one of the
following methods for removing the stuck part:
NOTE: QLX 40 does not have compression cone.
For QLX 50/55 and QLX 60/65 the distributor/compression cone
valve assy and guide plug will come out as an assembly. The
guide plug in the distributor is held in place by the detent kit.
The air select (guide plug) does not need to be
removed unless the air select is not adjusting
into select position. In this case remove plunger,
spring and plug and replace with new detent kit.
12
WARNING
• If the compression cone remains in the hammer when
the backhead is removed it will be held under very
high load by the spring action of the cylinder. when
released, the compression cone will be forcefully
ejected from the casing. Use caution when removing
the cone to avoid personal injury. Do not stand or
place any part of the body in front of the casing
opening when loosening the compression cone.
• If the compression cone is stuck in the cylinder, it
will be difficult to unscrew from the casing after the
joint is initially broken loose. The check seal is often
dislodged from its normal location as well.
• If this happens, tap the casing lightly with a soft faced
hammer or brass bar about 1/4 to 1/3 the casing length
from the backhead end of the casing until you hear a
loud snap which indicates the cone has unseated.
a. Carefully stand the casing on a flat, level surface, backhead
end down. Use a soft faced hamer or brass bar to tap the
casing lightly at the location of the top of the cylinder. The
compression cone will be released.
b. Partially reinstall the backhead or chuck to block the
compression cone when it releases with the hammer lying
horizontally, use a soft faced hammer or brass bar to tap the
casing lightly at the location of the top of the cylinder. The
compression cone will be released.
6. With a brass bar, push the piston upward from chuck end
towards backhead end until it contacts the cylinder, then strike
the end of the piston firmly with the bar to drive the cylinder
out of the retention groove in the casing. Once dislodged from
the retention groove, continue to tap the piston until the top
end of the cylinder comes out of the casing. The cylinder can
now be removed by hand.
Note: QLX 40 cylinder is NOT removable
7. The piston can be removed from the backhead end of the
casing by pushing it with a brass bar until it can be extracted
by hand.
Note: QLX 40 piston ONLY from chuck end once bearing and
bearing o-ring is removed
8. Remove the bit bearing from the hammer. The bearing can
sometimes be removed by hand, but often will require the use
of a bearing puller. When using a bearing puller, be sure it is
in contact with the bearing and not the bearing retainer. The
bearing can also be removed by inserting the piston (small
end first) into the backhead end of the casing and tapping the
piston with a brass bar to drive the bearing out of the casing.
Note: QLX 40 piston can not be used to remove bearing
9. Remove the bearing retainer ring from the casing. With the
piston in normal position (striking end facing the chuck end
of the casing) drive the bearing retainer ring out of its groove
using the brass bar. It may be easier to do this with the casing
in a vertical position (chuck end down).Be careful to avoid
striking the lip at the piston ID to avoid chipping the piston. It
may be helpful to place a block of wood or other soft material
on top of the piston to cushion against damage.