MANITOWOC ENGINEERING CO.
division of The Manitowoc Company, Inc. Manitowoc, Wisconsin 54220
GANTRY ASSEMBLY
3900W
PURPOSE
This Folio provides gantry raising and low-
ering instructions.
GENERAL
The gantry is partially raised and lowered
by the hydraulically controlled gantry lift-
ing device lever (3, Figure i). The boom
hoist rigging is used to completely raise
the gantry; also, the boom hoist rigging is
used to lower the gantry to the extended
position of gantry lifting device lever (3,
POSITION D, Figure i).
WARNING
*TO RAISE OR LOWER THE GANTRY, A MINI-
MUM BOOM LENGTH OF 60 FEET (BUTT, TOP
AND PENDANTS) IS REQUIRED.
*BEFORE RAISING OR LOWERING THE GANTRY,
THE EQUALIZER MUST BE PINNED TO THE
BOOM BUTT (LIFT, CLAM OR DRAG) OR TO
THE 40-FOOT TOWER INSERT. IF NOT DONE,
THE EQUALIZER MAY BOUNCE AGAINST THE
BOOM AND CAUSE DAMAGE.
DO NOT RAISE OR LOWER THE GANTRY, FROM
OR TO THE DOWN POSITION, WITH THE BOOM
HOIST WIRE ROPE. IF ATTEMPTED, STRUC-
TURAL DAMAGE MAY RESULT. THE GANTRY
LIFTING DEVICE MUST BE USED TO PARTIAL-
LY RAISE AND FULLY LOWER THE GANTRY.
PE_RSONNEL M77ST NOT REMAIN ON THE MACHINE
ROOF WHILE RAISING AND LOWERING THE
GANTRY. IF THE GANTRY DROPS, PERSON-
NEL MAY BE INJURED.
THE GANTRY MUST BE SUPPORTED BY THE
BOOM HOIST RIGGING BEFORE REMOVING THE
PINS IN THE BACKHITCH STRAPS; OTHER-
WISE, THE GANTRY WILL DROP AND MAY
CAUSE PERSONAL INJURY OR MACHINE DAMAGE.
The backhitch is of the telescopic type and
provides the following positions (see Figure
i):
A. The "LOW POSITION" is the shipping posi-
tion; it also provides minimum clearance
for travel (refer to the "Boom Rigging
Drawing" for boom handling instructions).
B. The "HIGH POSITION" is the working posi-
tion for lift, clam and drag machines.
Also, this position must be used to raise
and lower the tower attachment.
C. The "INTERMEDIATE POSITION" is the work-
ing position for tower cranes. Also,
this position must be used to raise and
lower the boom on tower cranes.
GANTRY OPERATION (FIGURE i)
A. TO RAISE GANTRY:
I. Pin the equalizer to the rails on the
boom butt (liftcrane) or tower insert
(tower crane), whichever is the case.
2. Remove pin (i, Position A) from each
intermediate strap (2).
3. Move the gantry lifting device control
to the "up" position and hold. Boom
down slightly to maintain some slack
in the boom hoist rigging. Release
the gantry lifting device control when
the gantry reaches the maximum position
of lever (3, POSITION D).
4. Move the boom hoist control to the
"boom-up" position and slowly raise
the gantry to Position B.
5. Install pins (i and 7, Position B) to
secure intermediate strap (2) to upper
and lower straps (4 and 5) on each side
of the gantry. Pins (7) are stored on
the machine.
NOTE
If the machine is a tower crane, pro-
ceed to erect the tower. Then, lower
the gantry to the "intermediate posi-
tion"; otherwise, leave the gantry in
the "raised position" for normal lift,
clam or drag operation.
8-28-70 (Rev. ii-13-79)* GANTRY ASSEMBLY
FOLIO
390-1
395143
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