PRODEM PRB008 - Chisel, Bushing, and Pin Wear Inspection

- 40 -
Accumulator gas charging pressure:
Hammer model
CHARHING
at ambient temperature;
20°C (68°F)
CHECKING
at operating temperature;
60~70°C (140~158°F)
bar
(psi)
bar
(psi)
PRB170
PRB200
PRB250
PRB300
PRB400
PRB500
PRB700
60 ± 2
(870 ± 30)
68 ± 2
(990 ± 30)
7.6. Chisel, wear bushings and
chisel pins
Operating the hammer, even though it is regular
and correct, wear the chisel and its wear parts such
as:
 Wear bushings; chisel bush, front bush
 Thrust ring
 Chisel pin, stop pins and PU-sleeves
 Wiper and wiper retainer (for SA version only)
These wear of chisel and wear parts is caused by:
 Wear by metal-to-metal sliding
 Tear of contact point by micro-welding
 Particle engaged abrasive wear
 Collapse or peeling of surface by extremely high
contact pressure
 Heat generated by friction accelerates wear
Check the chisel, chisel bush and front bush for
wear every 50 hours of hydraulic hammer use or
weekly. And, replace them if the amounts of wear
exceed the permissible wear limits.
If these parts are used beyond their wear limits, the
piston and chisel may be damaged severely.
Especially, when the hydraulic hammer has too
much clearance between the chisel and both wear
bushes, the chisel can be broken by bending
through wrong impacts.
Replacement of the parts below due to wear is not
covered by the warranty.
Chisel and wear parts in the front-head:
This is a general angled section view of front-head.
1. Piston 2. Chisel 3. Thrust ring
4. Chisel bush 5. Front bush 6. Chisel pin
7. Stop pin
2
7
7
3
4
6
5
1