Manitowoc 16000WA, Operator'S Manual

Page: 103 / 110

Reference
Only
Manitowoc
Published 03-18-13, Control # 116-09
6-7
16000 WIND ATTACHMENT OPERATOR’S MANUAL MAINTENANCE
6
BLOCK-UP LIMIT INSTALLATION AND
ADJUSTMENT
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 point.
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 sheaves and wire
rope, possibly causing load to fall.
The block-up li mi t system cons ists of the foll owing
components (Figure 6-5):
1. Boom node controller (5).
2. Normally closed limit switch assembly (14) at the
following locations:
a. Lower point.
b. Upper point.
3. Weight (12 or 18) freely suspended by chain from each
limit switch actuating lever (weight encircles load line as
shown).
4. Lift block on load block or lift plate on load line.
5. Cable reel (26) in boom butt which allows the cable to be
lengthened or shortened to meet varying boom lengths.
Disconnecting Block-Up Limits
See Figure 6-5 for following procedure.
Failing to perform following steps will prevent load
drums from hoisting and boom from lowering. Also, a
fault alarm will come on.
1. To provide proper operation, the electric cables from the
b l o c k - u p l i m i t s w i t c h e s m u s t b e c o n n e c t e d t o
receptacles (L and U) on boom node controller (5).
2. If a limit switch cable is disconnected from the boom
node controller, corresponding terminating plug (5a)
must be connected to the receptacle.
6
5
25
26
24
24
8
14
14 16
FIGURE 6-5 continued
5a
5a
WARNING
Two-Blocking Hazard!
Block-up limit control is a protective device designed only
to assist operator in preventing a two-blocking condition;
any other use is neither intended nor approved.
Block-up limit control may not prevent two-blocking when
load is hoisted at maximum single line speed. Operator
must determine fastest line speed that allows block-up
limit control to function properly and, thereafter, not
exceed that line speed.