(2) To adjust clearance at point A, remove
3-28. Hoist Clutch and Digging Clutch Adjustment
capscrew and lockplate then rotate adjusting sleeve
(eccentric) until a minimum clearance of 1/32 inch is
obtained at point A.
(1) Each main clutch has an auxiliary, or
(3) Establish approximately 1/16 inch
booster clutch, which is the unit most frequently
clearance at points B and C by backing off locknut (2)
requiring adjustment. However, determine which one
and turning the two adjusting screws until clearance is
actually requires adjustment by engaging the hand lever
controlling the clutch to be checked, then setting the foot
brake pedal controlling the same drum.
Clearance at point D will always be
greater than that at points A, B and
Setting the foot brake simulates a
C, and does not effect clutch
load on the drum. If this is not done,
the clutch will not "wrap in" to the
drum as it does during normal
should be adjusted just tight enough to prevent clutch
shoes from engaging the clutch drum when machinery is
(2) Engage the engine clutch long enough
rotated at full speed. These springs should not be
for the clutch to " rap in" then measure gap (fig. 3-22)
tighter than necessary to prevent clutch shoes from
between lug and stop on clutch spider. If there is less
than inch clearance between these points, the main
clutch linings are worn and must be tightened. If there is
(5) It may be necessary to bend the two
more than inch clearance between the above points
brackets slightly to get a good fit of the clutch shoe
the auxiliary clutch must be adjusted.
within the clutch drum.
Main Hoist or Digging Clutch Lining Wear
Adjustment. To compensate for lining wear on main
It is good practice, before linings are
clutch, loosen locknut on adjusting bolt (fig. 3-20) and
worn out, to exchange the dead shoe
turn adjusting bolt until clutch linings are in proper
for the live shoe. Most lining wear is
adjustment. Tighten locknut to hold the adjustment.
concentrated on the live shoe.
Main Clutch Shoe Adjustment.
(1) When clearance between clutch shoe
Be sure there is enough tension on
lining and the clutch drumpoints A, B and C (fig. 3-20)
exceeds 3/32 inch, or when new clutch
loose may cause breakage of release
Auxiliary (Booster) Clutch Adjustment.
(1) To compensate for normal clutch lining
wear, loosen locknut (fig. 3-23) and turn adjusting bolt.
Do not adjust nut for normal band wear adjustment.
Figure 3-22. Main hoist or auxiliary clutch lining
shoes are installed, the clutch shoes are installed, the
Figure 3-23. Auxiliary (booster) clutch adjustment
clutch must be adjusted for proper lining clearance.