c. Adjust digging brake and planetary clutch bands
turn adjusting bolt until clutch linings are in proper
adjustment. Tighten locknut to hold the adjustment.
in a similar manner.
c. Main Clutch Shoe Adjustment.
Caution: Do not adjust bands so tight that
(1) When clearance between clutch shoe lining
operation of lever is hard. Tight bands cause
and the clutch drum at points A, B and C (fig. 3-28)
excessive wear on linings and shorten their
exceeds 3/32 inch, or when new clutch shoes are
serviceable life.
installed, the clutch must be adjusted for proper lining
clearance.
3-32. Hoist Clutch and Digging Clutch Adjustment
(2) To adjust clearance at point A, remove
a. General.
capscrew and lockplate then rotate adjusting bolt
(1) Each main clutch has an auxiliary, or
(eccentric) until a minimum clearance of 1/32 inch is
booster clutch, which is the unit most frequently
obtained at point A.
requiring adjustment. However determine which one
(3) Establish
approximately
1/16
inch
actually requires adjustment by engaging the hand lever
clearance at points B and C by backing off locknut (2)
controlling the clutch to be checked, then setting the foot
and turning the two adjusting screws until clearance is
brake pedal controlling the same drum.
correct.
Note. Setting the foot brake simulates a load on
Note. Clearance at point D will always be
the drum. If this is not done, the clutch will not "wrap in"
greater than that at points A, B and C, and does not
to the drum as it does during normal operation.
effect clutch operation.
(2) Engage the engine clutch long enough for
(4) The tension of three springs (fig. 3-28)
the clutch to "wrap in", then measure gap (fig. 3-30)
should be adjusted just tight enough to prevent clutch
between lug and stop on clutch spider. If there is less
shoes from engaging the clutch drum when machinery is
than 1/2 inch clearance between these points, the main
rotated at full speed. Thee springs should not be tighter
clutch linings are worn and must be tightened. If there is
than necessary to prevent clutch shoes from dragging.
more than inch clearance between the above points
(5) It may be necessary to bend the two
the auxiliary clutch must be adjusted.
brackets slightly to get a good fit of the clutch shoe
within the clutch drum.
Note. It is good practice, before linings are
worn out, to exchange the dead shoe for the live
shoe. Most lining wear is concentrated on the live
shoe.
Figure 3-30. Main hoist or auxiliary clutch lining wear
determination.
b. Main Hoist or Digging Clutch Lining Wear
Adjustment. To compensate for lining wear on main
Figure 3-31. Auxiliary (booster) clutch adjustment
clutch, loosen locknut on adjusting bolt (fig. 3-28) and
points.
3-38
