Tadano TT-800XXL1, Service Manual

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G-1 G-1
Telescoping System
1
WG02-026 1 E
Telescoping System
1 . General
1 . 1 Telescoping cylinder
1 . The telescoping cylinders are incorporated in the
boom, and serve to telescope the boom to witch
they are connected by pins.
2. It telescopes the 2nd boom section, and
telescopes the 3rd, 4th and top boom sections
simultaneously using two double-acting hydraulic
cylinders and wire ropes.
1 .2 Counterbalance valve
1 . The counterbalance valve is directly connected to
the telescoping cylinder, and serves to prevent the
cylinder from retracting while the control lever is in
NEUTRAL, to prevent the cylinder from being
driven by the load during retraction, and to
prevent its violent retraction, when the hoses and
other parts of the extension circuit are damaged.
1 .3 Hydraulic valve
This valve is electrically controlled to selectively
deliver the pressurized oil from the hydraulic pilot
control valve into the No.
1 cylinder circuit or the
No.2 cylinder circuit.
1 .4 Hose reel
The hose reel serves to let out and take in the
hose as the boom telescopes to maintain the
hydraulic circuit to the No.2 cylinder all the time