TM 5-3820-233-12/1
4-63. Eccentric Shaft
The eccentric shaft is driven through an intermediate
countershaft from the jaw crusher drive. This shaft
incorporating a crank drive crank pin, connecting rod and
spring moves the aggregate along the feeder plate to the
jaw crusher. A shaft collar shear pin behind the spring
provides a safety device that will shear if crusher
becomes filled and rock blocks the normal travel of feeler
plate.
a. Removal. Refer to figure 4-57 and remove the
eccentric shaft as follows:
(1) Loosen chain drive tension and remove
chain.
(2) Remove bolts (3) and pull sprocket from
shaft.
(3) Remove pillow block bearing bolts (4) and
pull bearings from shaft.
(4) Disconnect drive crank assembly from
connecting rod.
b. Installation. Inspect all parts for cracks, breaks or
defects. Replace a defective part.
c. Installation. Refer to figure 4-57 and install the
eccentric shaft in the reverse of removal.
4-64. Eccentric Drive Adjustment
a. The feeder eccentric driving mechanism for the
reciprocating feeder is adjustable and the length of the
stroke of the feeder plate governs the quantity of the
material moved into the crusher per revolution of the
Figure 4-57. Eccentric shaft, removal and installation.
eccentric shaft.
b. The arm of the eccentric driving mechanism is
c. Normally, if material consistently builds up in the
connected to the safety spring device on the bottom of
crusher hopper, the feeder stroke should be shortened;
the feeder plate shown in figure 4-58. The reciprocating
or lengthened if the crusher is not receiving enough
motion of the driving mechanism is transferred to the
material. Length of stroke is controlled by the position of
feeder plate through the safety spring. The coil spring
the crank pin and crank drive assemblies. The stroke
normally is compressed sufficiently to withstand normal
can be changed from a neutral position to a maximum
feeding loads, but will compress and then shear the shaft
six inch stroke in one-half inch adjustments as follows:
collar pin in the event the crusher hopper becomes full of
(1) Loosen the crank pin bolt.
material and blocks the normal forward movement of the
(2) Move crank pin to any mating corrugation in
feeder plate. Of course this condition should be avoided
the drive crank assembly.
as the operator has the option to dis-engage the feeder
(3) Check feeder plate stroke for proper length.
until the crusher has crushed the excess material in the
(4) Tighten bolt after required stroke is located.
hopper.
4-54
