CHAPTER 4
REVOLVING FRAME REPAIR INSTRUCTIONS
Section I. GANTRY AND SHEAVE YOKE
(6) Reassemble gantry sheave yoke by reversing
4-1. General
procedure in steps (5) through (1) above.
The gantry is a framework consisting of a truss, front
c. Cleaning, Inspection, and Repair.
legs, braces, and rear tension members, mounted on
rear of revolving frame and partially within cab. The
(1) Clean all parts and dry thoroughly.
shaft and sheave, along with sheave yoke are installed
(2) Visually inspect spreader bar and yokes for
atop the cab rear canopy and attached to gantry by
bends, cracks, or other defect. Check sheaves and
adapters.
bushings for wear or damage.
Check mounting
hardware for burs, stripped threads, or other damage.
4-2. Gantry Sheave Yoke and Adapters
Check bearing block for scoring or other defect.
(3) Repair by straightening bends, welding
a. Removal or Installation.
cracks, or replacing damaged parts or defective
mounting hardware.
(1) Remove gantry sheave yoke (TM 53810-201-
12).
4-3. Gantry
(2) Remove two capscrews (20, fig.
lockwashers (21), and keeper plate (22), then drive shaft
a. Removal and Installation. Refer to paragraph 2-8
(19) from left and right adapters (25) and (28).
for instructions on removal or installation of gantry.
(3) Remove cotterpins (23), and pins (24) from
adapters (25) and (28).
Remove four nuts (26),
b. Disassembly or Reassembly.
lockwashers (27) and bolts (29), then lift adapters (25)
and (28) from gantry.
(1) Remove setscrew (15, fig. 2-3) and sheave
(4) Install adapters and gantry sheave yoke by
guard (16) from end of shaft (3).
reversing procedure in steps (3) through (1) above.
(2) Remove bushing (17), sheave (18), and
washers (20) from shaft (3). Remove fittings (19) from
b. Disassembly or Reassembly.
sheave (18).
(3) Remove 12 nuts (22), lockwashers (21), and
(1) Remove cotterpin (32) from bolt, special (33),
bolts (7) which secure braces (5) and (6) to truss (4),
and remove bolt and rope socket (8). Keep wedge (9)
then remove braces from truss.
with rope-socket.
(4) Remove two screws (29) and keeper plate
(2) Remove four screws (3) from two keeper
(28) from truss (4); remove shaft (3) and pipe spacers
plates (2) then remove spreader (1) from sheave yokes
(1) and (2) from truss (4), then remove front legs (23)
(31).
and (27) from truss.
(3) Remove two pins (11) from sheaves (14);
(5) Remove four cotterpins (8) from two pins (9),
remove fittings (12) from pins (11), then remove two
then remove two pins and two tension members (10)
sheaves (14) from yokes (31). Remove two bushings
from truss (4).
(13) from sheaves (14) only when replacement is
(6) Reassemble gantry by reversing procedure in
required.
steps (5) through (1) above.
(4) Remove eight nuts (30), lockwashers (21)
and bolts (16) from four blocks (17), then remove yokes
c. Cleaning, Inspection, and Repair.
(31) and blocks (17).
(5) Remove eight nuts (6), lockwashers (5), and
(1) Clean all parts and dry thoroughly.
bolts (4), then remove gusset (7) from spreader bar (1).
(2) Visually inspect truss, braces, legs, or shaft
for bends, cracks, or other damage.
4-1
