mover. The Model 2A-2B screening unit is equipped with
4-71. Size of Feed
a. The size of material fed to the roll crusher is
discs wheels and 16:5 x 22: 5--16-ply tires, 65 lbs.
determined by the size of the discharge opening and
diameter of the shells. Recommended sizes are shown in
table 4-3.This feed size
is for average conditions and will
Both the secondary screening unit and the
b. Material fed into the roll crusher must be of a size
dolly have the same wheel, tire and service
or reduced to a size which the roll crusher is capable of
brake arrangement and can be removed in the
crushing, to a further reduced finished specified
c. Generally, an additional crusher must be used to
and remove and disassemble the wheel, tire, and brake
handle the primary crushing to reduce oversized material
assembly as follows:
to a size readily handled by the secondary roll crusher.
remove wheel assembly (2) from hub (14).
A balanced plant for maximum production. All
(2) Delfate tire air pressure and remove tire (3)
rock crushing plants are designed from feed to
from wheel (TM 9-1870-1).
(3) Remove bolt (5) and remove hub cap (7) from
delivery for a balanced production ratio.
Conveyors, screens, the primary and
(4) Remove outer spindle nut (9) and inner spindle
secondary crusher, are of the correct size to
nut (11) from axle.
handle the anticipated tonnages under most
(5) Remove the brake drum (12).
crushing conditions encountered, keep in
(6) Remove hub studs (13) and remove the hub
mind that correct crusher settings and
selection of screen wire are all in vain if the
(7) Remove the inner and outer cone bearings (15
plant is not properly operated and maintained.
and 18) from hub (14).
(8) Remove nut (20), washer (21) and bolt (22).
Table 4-3. Recommended Feed Size (Note 1)
(9) Remove slack adjuster assembly (25) and
remove the brake assembly (24).
(10) Remove screw (25) and remove dust shield
24" roll shell
(26) from brake assembly.
(11) Disconnect rod assembly and remove the air
brake chamber assembly (27).
(1) Inspect the tire (3, fig. 4-72) for excessive wear
or cuts. Replace a defective tire (TM 9-1870-1).
(2) Inspect the wheel (2) for damage.
(3) Inspect the brake drum (12) for cracks and
(4) Inspect the bearings (15 and 18) for excessive
wear and inspect the bearing cups (16 and 19) for scoring
(5) Inspect the slack adjuster (23) and air chamber
(27) for damage and proper operation.
NOTE 1--Based on regular shaped particles with relatively smooth
(6) Inspect brake assembly for excessive wear.
surfaces. Irregular shaped particles and/or particles with relatively
(7) Inspect all hardware for damage and replace
rough surfaces, permit slightly larger feed
all defective parts.
NOTE 2-Recommetded particle sizes are within the prescribed
reduction ratio. Maximum particle sizes are the permissible
and install the brake assembly, tire and wheel in the
occasional oversize particles that will be gripped under average
reverse order of removal.
e. Adjustment. Adjust brakes as follows.
(1) Turn adjustment stud end of slack adjuster
4-72. Secondary Screening Unit, Wheel, Tire and
worm shaft until the brake drags.
(2) Turn stud slowly in opposite direction until
a. General. The Secondary crushing and screening
brake is free of drag.
unit is equipped with service brakes on each wheel and
(3) Lower unit and road test for brake balance.
which are controlled by the air brake system of a prime