Tadano TR-800XXL4, Service Manual

Page: 169 / 402

H - 1 . H - 1 .
Safety System
1
WH02-0080E
H-1 Safety System
1. General
1.1 Pressure sensor
1. A retraction pressure sensor and an extension
pressure sensor are incorporated in the elevating
cylinders.
2. They convert the elevation pressure into the
electric signal and transmit it to AML (Load
moment indicator) main body, making the limiter
calculate the total moment created by the lifted
load and the mass of the boom.
1.2 Boom length and angle detector
The Boom length and angle detector is installed
on the boom side, and uses the potentiometer
inside the detector to convert the extended boom
length and the angle of the boom relative to the
ground into an electric signal that is transmitted to
AML main body.
1.3 Outrigger extension width detector
It is installed on the rear end of the outrigger outer
case. The potentiometer in the detector converts
the outrigger extension width into the electric
signal and transmits it to AML main body.
1.4 Other detectors and switches
The outer detectors and switches convert the
crane operation modes and working conditions
into an electric signal that is transmitted to AML
main body.
1.5 AML (Load moment indicator) main body
1. AML main body calculates the moment being
generated on the crane based on signals from the
pressure sensor and the Boom length and angle
detector.
2. The calculation result is compared with the rated
moment and,when it reaches 90% and 100% of
the rating, AML sends alarm and auto. stop
signals, respectively, to prevent the crane from
being overloaded.
1.6 Overwind cutout (Anti-twoblock) device
The anti-twoblock device prevents damage to the
crane that would be caused by pulling the hook
block into the boom head. When the hook block
approaches the boom head, single top or jib, the
overwind cutout device sends a signal to AML,
which then stops any further crane action toward
the critical condition.
1.7 Solenoid valve
1. If AML malfunctions or if the actual moment
reaches 100% of the rated moment or the hook
block is over-hoisted, an electric signal (auto.
stop) is sent from AML main body to this valve.
2. When the solenoid valve is deenergizied, this
solenoid valve contents the vent line of the relief
valve mounted on the hydraulic pilot control valve
to the tank. The solenoid valve by allowing the
pressurized oil from the pump to escape through
the relief valve to the tank, therefore the crane
operation stops.
2. Description of system
Refer to the repair manual of AML-L.