(4) Lash saddle blocks to boom so that they
4-4. Shovel Dipper a. Removal.
are prevented from changing angles when dipper handle
(1) Lower dipper to rest on blocks, then
is removed from shipper shaft.
remove hoist cable from bail sheave only (fig. 2-19).
(5) Fasten one end of a heavy rope about
(2) Refer to figure 4-4, disconnect trip chain
three feet from dipper end of handle, the other end of
from trip lever, remove cotterpins from two pins
rope to boom point of lifting device. Move dipper
securing braces to dipper handle, then remove pins.
handle until pointed end is almost at shipper shaft, and
(3) Remove cotterpin and washer from two
almost free of saddle blocks.
handle pins, remove handle pins, then remove dipper
(6) Lower dipper end, if necessary, then work
from handle.
points of handle over pinions, carefully, and lower dipper
b. Disassembly and Reassembly of Dipper.
handle to ground.
(1) Remove cotterpin and bail pin (fig. 4-4),
b. Installation.
then remove bail.
(1) Position shovel boom to receive dipper
(2) Remove bolt from chain at latch lever,
handle, making sure saddle blocks are lashed secure to
then remove chain.
boom.
(3) Remove cotterpin and pin from two
(2) Position lifting device, and clamp hoist
braces, then remove braces.
cable around dipper handle at balance point (about
(4) Remove two bolt and nut from latch lever,
three feet from dipper end).
remove latch lever, then remove clevis and latch bar
(3) Lash a heavy rope to point end of handle,
from dipper door.
thread it through, or over shipper shaft, then station one
(5) Remove cotterpin from two door hinge
man on each side of boom to help guide dipper handle
pins, remove pins, then remove dipper door.
into saddle blocks.
(6) When necessary to remove latch keeper
(4) Pull hoist cable in slowly and move lifting
for repair or replacement, remove two short and four
device forward.
long rivets then remove keeper.
(5) Guide dipper handle into saddle blocks,
(7) Disassemble bail (para 4-6).
making sure that racks engage with pinions on shipper
(8) Reassemble in reverse order of
shaft.
disassembly.
(6) Install boom crowd chain over sprocket on
c. Cleaning, Inspection, and Repair.
shipper shaft and crowd and reversing mechanism at
(1) Clean all parts with an approved cleaning
foot of boom and secure with master pin, roller, and
solvent and dry thoroughly.
cotterpin (para 4-3).
(2) Visually inspect all parts for signs of
(7) Install dipper trip cable on dipper handle
excessive wear, cracks, breaks, bends, stripped threads
on hardware, or elongation of holes.
(8) Install shovel dipper (para 4-4).
(3) Repair by welding cracks or breaks,
4-6. Dipper Bail and Sheave
straightening bends, and replacing all defective
a. Removal.
hardware or excessively worn parts.
(1) Remove shovel dipper (para 4-4).
d. Installation.
(2) Remove bail (para 4-4b (1)).
(1) Position dipper at end of dipper handle,
b. Disassembly and Reassembly.
install two handle pins and secure each with washer and
cotterpin.
(1) Remove cotterpin and slotted nut from
(2) Place two braces at lugs on dipper
sheave pin.
handle, install pins and secure with cotterpins.
(2) Remove sheave pin, then remove sheave
(3) Connect door trip chain to trip lever, then
from bail.
reeve hoist cable (fig. 2-19).
(3) Reassemble by reversing steps (1) and
(2) above.
4-5. Dipper Handle
c. Cleaning and Inspection.
a. Removal.
(1) Clean all parts in an approved cleaning
(1) Open boom crowd chain by removing
solvent and dry thoroughly.
cotterpin, roller, and master pin, then lifting chain off
(2) Visually inspect sheave for scored sleeve
sprocket on shipper shaft.
bearing, cracks, worn groove, or other defect. Inspect
(2) Remove shovel bucket (para 4-4).
bail for cracks, breaks, elongated mounting holes, or
(3) Remove dipper trip cable from dipper
defective mounting hardware. Replace all defective
handle (para 4-8).
parts.
d. Installation.
(1) Install bail on dipper (para 4-4b).
(2) Install shovel dipper (para 4-4d).
4-5
