Figure 4-7. Gantry (2100J953)
2. Remove the lock pins that hold the compression mem-
bers to the lower tension member bracket.
3. Slowly rotate the boom hoist drum to take the slack out of
When the machine is operational, the gantry
the boom hoist lines. As tension increases in the boom hoist
should be lowered for TRAVELING UNDER AN
lines, the gantry will rise.
OBSTRUCTION ONLY. If the boom length is
4. Install the intermediate tension member lock pins in the
over 80 feet, the gantry must not be lowered.
vertical position, place the washers on the
When moving the machine with the gantry in
the pins with cotter pins.
the "travel position", the boom point must not
be raised higher than 12 feet. Do not attempt to
LOWERING THE GANTRY. There are two reasons for lower-
lift a load with the gantry in the lowered posi-
ing the gantry: (1) to move the machine under an obstruc-
tion at the job site, and (2) to prepare the machine for travel.
1. Lower the boom onto blocking with a minimum clear-
Lowering the gantry is accomplished as follows (see Figure
ance of 6 inches at the boom point. Keep tension in the