Komatsu ecot3 PC300LC-8 Shop Manual page 284

SEN01998-05
1) Swing lock and swing holding brake func-
tion
q The swing lock function (manual) is used
to lock machine from swinging at any posi-
tion. The swing holding brake function
(automatic) is used to prevent hydraulic
drift after the machine stops swinging.
Operation of swing lock switch and swing
q
lock/holding brake
Lock Lock Func-
switch lamp tion
Swing
OFF OFF holding
brake
Swing
ON ON
lock
Swing holding brake release switch
q If the controller, etc. has a problem, the
swing holding brake does not work nor-
mally, and the machine cannot swing, the
swing lock can be reset with the swing
holding brake release switch.
Even if the swing holding brake release
q
switch is turned on, if the swing lock
switch is turned on, the swing brake is not
released.
q If the swing lock is reset, only the hydrau-
lic brake is applied by the safety valve.
Note that if swinging is stopped on a
slope, the upper structure may swing by
its gravity.
Swing
holding ON
brake (when controller has
release trouble)
switch
Swing lock
ON
switch
Swing lock Swing lock
Swing
is turned
brake
on.
26
Operation
If swing lever is set in
neutral, swing brake
operates in about 7 sec.
If swing lever is oper-
ated, brake is released
and machine can swing
freely.
Swing lock operates and
machine is locked from
swinging.
Even if swing lever is
operated, swing lock is
not reset and machine
does not swing.
OFF
(when controller is nor-
maly)
OFF ON OFF
Swing
Swing lock
holding
is can- is turned
brake is
celed. on.
turned on.
10 Structure, function and maintenance standard
2) Quick hydraulic oil warm-up function when
swing lock switch is turned on
q If swing lock switch (1) is turned on, the
pump cut-off function is cancelled and the
relief pressure rises from 34.8 MPa {355
2
kg/cm } to 37.2 MPa {380 kg/cm
work equipment is relieved under this con-
dition, the hydraulic oil temperature rises
quickly and the warm-up time can be
shortened.
2
}. If the
PC300, 350-8