J&M 220 Operating And Maintenance Manual - page 43
MODEL 220
HYDRAULIC
IMPACT HAMMER
IV.
MAINTENANCE AND ADJUSTMENTS
N. SETTING VARIABLE STROKE CONTROL (CLAMP) RELIEF VALVE
1. Locate stroke control relief valve (P/N 100898) on power unit clamp manifold.
Manifold is located behind the small quick disconnects at the coupler panel.
See page VIII-44 item 4.
2. While holding the valve adjusting screw with an open end, loosen the adjusting
screw jam nut with an open end wrench.
3. Make an initial adjustment of the screw by turning it approximately 1/8th turn in
the desired direction. (Turning the screw clockwise will increase the pressure
setting. Turning counter-clockwise will decrease pressure.)
CAUTION: NEVER ADJUST THE RELIEF VALVE WHILE THE SYSTEM IS UNDER
PRESSURE.
4. Close all power unit doors.
5. Disconnect the variable stroke control (smallest) disconnects at the power unit.
6. Start and warm up diesel engine. When engine is warmed up, increase engine
RPM to maximum.
7. While observing the CLOSE pressure gage, turn the CLAMP switch to CLOSE.
The pressure should read 1500 PSI (103 Bar).
8. If the pressure is not correct, repeat steps 3 thru 8.
9. When the desired pressure is achieved, hold the adjusting screw with an open
end wrench and tighten the adjusting screw jam nut.
10. Do not reset the variable stroke control pressure by adjusting the "Clamp
Pressure Switch".
O. TENSIONING WIRE ROPES
1. Clean dirt and excess paint from the threads on the wire rope assembly. Check
that the centering nut and the lock nut can be fully threaded onto these threads
by hand.
2. Install the wire rope assembly from the bottom plate of the hammer. If the rope
gets stuck between the bottom plate and the top plate, it is often helpful to twist
the rope while pushing the rope through. After the threaded end of the rope
assembly exits the top plate, it will be necessary to hand guide the end of the
rope through the lifting bale to the top rope mounting hole. USE EXTREME
CAUTION NOT TO DAMAGE THE THREADS. Grease the threads.
IV-10