Fig. WH 171
Fig. WH 172
General Information
The illustrations and wiring diagrams shown are: Fig. WH 171 (without additional hydraulic function) and Fig. WH 172 (with additional hydraulic function).
The left hand pump supplies pressure oil to the left hand valve bank (connection A4) for the hydraulic hammer operation. The items in the illustrations function as follows:
(1) Shutoff valve in the operator's cab.
(2) Change-over valve (two-way valve).
(3) Hammer actuation solenoid valve. The valve is affected by an electrical pedal, item (6).
(4) Valve plate. The valve block has a solenoid valve (4a), which is closed when not energized and open when energized. For hammer operation, the valve is opened by pulling the electrical switch (5). The valve block also has the pressure limit valve (4b) to control the hammer pressure.
(5) Electrical pull switch (in operator's cab)
- push to enable excavator operation
- pull to enable hammer excavation
(6) Electrical pedal switch (in operator's cab) to switch hammer OFF/ON, foot operated. When relieved, hammer operation is OFF.
(7) Electrical pull switch (in operator's cab) to vary hammer stroke rate (only if equipped). Pull or push the switch to vary the hammer stroke rate. The switch activates solenoid valve (9).
(8) Electrical relay disables hammer operation when the solenoid valve (4a) is deenergized, although the pull switch (5) is in the pulled condition.
(9) Solenoid valve, stroke rate adjustment (only if equipped).
(10) Shutoff valve, outside the operator's cab, between the two control valve banks.
(11) Check valve in hammer pressure line (only if equipped).
(12) & (13) Solenoid valves of additional hydraulic features (in Fig. WH 172 only).
(14) Electrical contact on right transducer. Activates solenoid valves (12) and (13) in Fig. 172 only.
- - Close shutoff valves (1) and (10).- Pull switch (5).
- - Open shutoff valves (1) and (10).- Press switch (5).
- - Close shutoff valves (1) and (10).- Press switch (5).
Pressure Adjustment
 |
Make reference to WARNING on first page of TESTING AND ADJUSTING Section. |
 |
(Disconnect hammer oil lines or block off the lines on the boom.)
Observe the proper sequence.
1. Test the solenoid valve (4a) for 200 to 210 bar (20 000 to 21 000 kPa) pressure setting.
a. Push electrical switch (5) to enable excavator operation.
b. Use setscrew to fully back out or zero the pressure limiter valve, after first loosening the small lock screw.
c. Open shutoff valves (1) and (10) and extend boom actuator against its stop.
- Alternately (with additional hydraulic feature incorporated).
- Close shutoff valve (1) and (10) and use additional hydraulic feature to build up pressure with the hammer line (connection line A4, on left control bank) blocked.
- Then, when the 200 to 210 bar (20 000 to 21 000 kPa) are not achieved use the knurled setwheel to adjust accordingly. Secure with the lock screws.
2. Adjust hammer pressure with pressure limiter valve (4b) (small valve flange-mounted to housing with red setscrew).
a. Close shutoff valves (1) and (10).
b. Pull electrical switch (5) to enable hammer operation.
c. Operate pedal (6) to build up pressure with the hammer line blocked. Adjust the setscrew of the valve inward until the specified pressure is obtained.
d. Use the lock screw to secure the setscrew.
NOTE: In the energized (hammer mode) condition only, the pressure setting of valve (4b) (hammer pressure) will be present. In the nonenergized (excavator mode), the pressure of valves (4a) and (4b) are added together. In this condition, protection is provided by the line relief valve 350 bar (35 000 kPa) at the left control bank because the sum of both pressures is greater. Make the settings at maximum engine speed.