Komatsu WA20-2, Operation & Maintenance Manual

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12.11.1 ADJUSTING BUCKET POSITIONER
(WA30, 40, 50)
1. Lower the bucket to the ground and adjust the bucket to the
desired digging angle. Set the work equipment control lever at
HOLD, stop the engine and adjust as follows.
2. Loosen two bolts 1 and adjust mounting bracket 4 of the
proximity switch so that the rear tip of bar 2 is in line with the
center of the sensing surface of proximity switch 3 . Then tighten
the bolts to hold the bracket in position.
3. Loosen 2 nuts 5 and adjust so that the clearance between the
sensing surface of proximity switch 3 and bar 2 is within a
range of 3 – 5 mm (0.12 – 0.20 in), then secure in position.
4. Adjust the proximity switch so that dimension a at the end of
proximity switch mounting bracket
4 and the sensing surface of
proximity switch 3 is at least 1 mm (0.04 in), then secure in
position.
Tightening torque: 17.2 ± 2.5 N•m (1.75 ± 0.25 kgf•m, 12.7 ± 1.8 lbft)
5. After adjusting, start the engine and raise the lift arm. Operate
the work equipment control lever to the DUMP position, then
operate it to the TILT position and check that the work equipment
control lever is automatically returned to HOLD when the bucket
reaches the desired angle.
12.11.2 BUCKET LEVEL INDICATOR
A and B at the top rear of the bucket are the level indicators,
so the bucket angle can be checked during operations.
A : Parallel with cutting edge
B : 90° to cutting edge
12. OPERATION 12. OPERATION
12.11 ADJUSTING WORK EQUIPMENT POSTURE

WARNING
‡ Stop the machine on flat ground and put blocks in front and
behind the wheels.
‡ Apply the parking brake.
‡ Secure the front and rear frames with the safety bar.
‡ Do not go under the work equipment when the arm is raised.
The boom kickout makes it possible to set the bucket so that it
automatically stops at the desired lifting height (lift arm higher than
horizontal) and the bucket positioner makes it possible to set the
bucket so that it automatically stops at the desired digging angle.
The setting can be adjusted to match the working conditions.