Emergency Stop Procedure To Lower Front Attachment - Hitachi EX27U Operator's Manual

EMERGENCY STOP PROCEDURE TO
LOWER FRONT ATTACHMENT
CAUTION: Prevent personal injury. Confirm that
no one is under the front attachment before start-
ing the procedure below.
If the engine stalls and cannot be restarted, lower the
boom to lower the bucket to the ground referring to the
emergency boom lowering procedure stated below.
If an accident occurs, get immediate medical attention. Any
fluid injected into the skin must be surgically removed
within a few hours or gangrene may result.
CAUTION: Keep workers from entering the area
under the front attachment.
1. Release air pressure from the hydraulic oil tank by
loosening cap (1) located on the top of the tank.
2. Remove the cover to access the control valve.
CAUTION: Slowly loosen the cartridge while
checking the lowering speed of the front attach-
ment. Failure to do so may cause the boom to
quickly fall.
IMPORTANT: Do not use a ratchet spanner as loosen-
ing and re-tightening the cartridge must
be quickly repeated.
3. While holding the hexagonal section of overload relief
valve cartridge (2) located on the boom cylinder bot-
tom side, slowly loosen the relief valve cartridge. The
boom cylinder bottom side port in the control valve is
routed to the hydraulic tank passage, allowing the
boom to lower.
: 14 mm.
: 19.6 N⋅m (2 kgf⋅m)
OPERATING THE MACHINE
5-22
1
2
SA-031
M571-07-019
2
M552-07-100
M552-07-101