Unic URW295CR, Maintenance Manual

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(4) When T eles coping C ylinder2 retracts
S lide pipe
C heck valve 2
S lide pipe
P iston
R od
S pool
P ressure
Oil
To tank
P ilot
P ressure
C ounter balance
Valve
P iston
Apply"Lock Tight#638".
S elector valve ass’y
C heck valve 2
S elector valve ass’y
R od
C heck valve 1
C heck
valve
B olt
Tele2
S pool
C heck valve 1
B olt
Tele3
Tele1
Tele2
Tele3
P ipe for cord reel
C ounte rbalance
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 retracted
P ressure oil flows through the dual cylinder of cylinder rod of tele1
to enter the retraction side of tele2.
Also, the bolt for tele3 opens the check valve 1 of selector valve ass’y
via spool which leads the oil in the extension side of tele2 to the counter-
balance valve by way of the slide pipe of tele2, the check valve 2 of selector
valve ass’y for tele1, and the slide pipe of tele1.
Although the check valve in the counter-balance valve is closed at
this time, the spool is opened by pilot pressure from the retraction side
allowing the oil in the extension side to return to the tank.
T his allows the tele2 to retract.
Although pressure is applied to the retraction side of tele1 at the
time, the tele1 will not be actuated because the check valve 1 of selector valve
ass’y is closed and the passage to the extension side of tele1 is shut off.
And the tele3 also will not be actuated according to the same
reasons as in the tele1.
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