e. Engage boom hoist clutch by pulling boom hoist
lever toward operator just enough to take pressure off
pawl, then disengage pawl. Return boom hoist lever to
neutral, slowly, to assure that brake will hold boom.
Readjust if necessary. After adjustment is complete,
engage boom hoist pawl, move boom hoist lever away
from operator to release brake, then check levers for
position described in note in d. above.
3-35. Crowd Chain Adjustment
adjusting nut on the two studs.
b. Lift up on tightened sprocket to tighten, or lower to
loosen boom crowd chain, then tighten adjusting nuts.
c. Proper adjustment allows from three to four
inches of sag in chain between shipper shaft sprocket
and chain tightened sprocket.
d. Adjust revolving frame crowd chain in a similar
manner.
3-36. Antisway (Boom Foot) Spring Attachment
a. Tension on antisway springs allows boom some
freedom of movement, yet prevents excessive swaying.
Figure 3-36. Dipper trip adjustment points.
At installation, tighten adjusting nut (fig. 3-35) to
compress spring until it is 145/8 inches in length.
c. Loosen lever locknut and adjust setscrew so that
Caution:
Never tighten enough to remove
travel of rod is stopped before lever is bottomed in
clearance between coils.
If spring coils are
upper clevis and bends rod.
bottomed, all strain will be transferred to boom foot
d.When brake shoe adjustment is correct, tighten two
lugs and damage to the revolving frame will result.
locknuts on rod, and locknut on setscrew, to hold the
b. Operator will check shovel antisway springs
adjustment.
frequently. When length of spring is correct, but
excessive sway occurs because of weakened springs;
3-38. Trip Cable Adjustment
replace old springs with new, and adjust as directed in a.
a. Assure that trip cable is fastened to equalizer
above.
bracket (fig. 3-37) with a cable clamp; loosen clamp at
bellcrank; take up all slack, then refasten cable clamp at
3-37. Dipper Trip Adjustment
bellcrank.
b. Assure that boom trip cable is reeled correctly;
rotate when dipper trip lever (fig. 2-23) is operated, the
from take-up drum mounted on shipper shaft; through
brake shoes (fig. 3-36) are probably worn enough to
equalizer sheave on equalizer bracket, then over idler
require adjustment.
sheave to dipper trip lever mounted on dipper sticks
b. Turn the bellcrank (underneath revolving frame)
near dipper.
until the brake shoe just barely drags against brake
c. If there is any slack in boom trip cable; loosen
drum, then turn bellcrank back until brake shoe is just
cable clamp at dipper trip lever; take up slack until
clear of the drum, then loosen locknuts on rod and
dipper trip lever is just downward from perpendicular to
adjust length of rod until top and bottom levers are both
the dipper sticks, then secure cable clamp.
from 15 to 20 degrees below a horizontal position.
d. Adjust length of trip chain as required.
3-42
