Unic URW295CR, Maintenance Manual

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(3) When T eles coping C ylinder2 extends
P iston
Apply "Lock Tight#638".
S lide pipe
P ressure Oil
To tank
S elector
valve ass’y
C heck valve 2
C heck valve 2
S lide pipe
S elector valve ass’y
P iston
R od
R od
C heck
valve
B olt
Tele3
C heck valve 1
S pool
C heck valve 1
B olt
Tele2
Tele1
Tele2
Tele3
P ipe for cord reel
C ounterbalance
valve
After the set-screw is tightened with Lock Tight #2701
applied
、
hit with a punch at 2 places on the
circumference and leave it as it is for 1 hour.
How oil flows when tele2 is extended
P ressure oil opens the check valve in the counter-balance valve to
enter the cylinder rod of tele1 and flows through the slide pipe to reach the
check valve 2 of selector valve ass’y.
S ince the slide pipe of tele1 is pulled by piston immediately before the
tele1 is fully extended which in turn opens the check valve 2 of selector valve
ass’y to lead the pressure oil to the extension side of tele2.
S imultaneously, oil in the retraction side of tele2 flows through the
dual cylinder in the cylinder rod of tele2 and through the dual cylinder in
the cylinder rod of the tele1 to return to the tank.
T his allows the tele2 to extend.
S ince the check valve 1 of selector valve ass’y of tele1 is closed at this
stage, the passage on extension side for tele1 is shut off.
T he tele1 will not be actuated because no oil is remained in the
retraction side of tele1 as the tele1 is fully extended.
In addition, the tele3 will not be actuated because the check valve 2
of selector valve ass’y for tele2 is closed which in turn shuts off the passage
to extension side of tele3.
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