T039810E
Other Safety Devices Deactivation of the Anti-twoblock Function
Anti-twoblock Device
WARNING
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 anti-twoblock device sends a signal to the load moment indicator (AML-L), which then stops any further crane action toward the critical condition. When overwinding is detected, the crane will be set in the following status: (1) Any operation involving action toward the critical state (hoisting up, extending or lowering the boom) is halted. (2) The alarm buzzer sounds continuously and a message appears on the moment indicator of the AML-L. When the crane is automatically stopped because the anti-twoblock device has been activated, retract the boom or hoist down to move the hook block away from the boom head, single top or jib. ◆The anti-twoblock device for the jib can also be used for the single top. ◆When the jib or single top is mounted, be sure to connect the leads of the anti-twoblock device correctly. If the leads are not connected, the load moment indicator assumes a two-blocking condition, and all actions toward the critical conditions are automatically stopped. ◆Once two-blocking has occurred, the alarm buzzer keeps sounding until the hook block is lowered.
Anti-twoblock disable switch OFF
ON
UEL
AML
F
Jib
Use the anti-twoblock disable switch to deactivate the anti-twoblock function. The anti-twoblock function may hinder stowing the main hook block and mounting or stowing the jib. If this happens, deactivate the function temporarily by pressing the anti-twoblock disable switch. While the switch is held down, the anti-twoblock function is deactivated.
H
Boom
When the anti-twoblock function is deactivated, the stop function will not operate even if the hook block is overhoisted. Be careful not to two-block the crane when deactivating the anti-twoblock function is unavoidable or specifically required.
L
T30420E
◆When the jib set status is registered in the load moment indicator (AML-L), the anti-twoblock function will be deactivated.
Single top
Twoblocking detector switch T02951E-1
Other Safety Devices
55
Other Safety Devices
