Manitowoc MLC80A-1 User Manual

Manitowoc Published 10-09-2020, Control # 259-06 5-29
MLC80A-1/MLC90A-1/MLC100A-1/MLC100-1 SERVICE/MAINTENANCE MANUAL HOISTS
5
General
The block-up limit control (also called anti-two-block device)
is a two-blocking prevention device which automatically
stops the load drum from hoisting and the boom from
lowering when a load is hoisted a predetermined distance
from either jib point.
Two-Blocking Definition
Two-blocking is the unsafe condition in which the load block
or the weight ball contacts the sheave assembly from which
either is suspended.
Two-blocking can result in failure of the sheaves and the wire
rope, possibly causing the load to fall.
For identification and location of the block-up limit
components in the boom, see the Operator and Service
Manuals supplied with the crane.
Cranes with Main Hoist Only
If the crane is operated with a main boom extension or top
section, the connecting cable must be mounted between the
distributor socket on the extension or insert, and the
distributor socket on the main boom. The main boom A2B
switch weight must be disconnected and mounted on the
extension or fly section A2B switch.
WARNING
Two-Blocking Hazard!
The block-up limit control is a protective device designed
only to assist the operator in preventing a two-blocking
condition. Any other use is neither intended nor approved.
Failure to reposition the A2B weight will prevent the A2B
system from functioning properly. No weight shall be
mounted on the A2B switch of the main boom when
working with the extension/top section.
FOR REFERENCE
ONLY

Manitowoc MLC80A-1 Specifications

General

Brand	Manitowoc
Model	MLC80A-1
Category	Construction Equipment
Language	English