Lesson 1/Learning Event 6
Hydraulic Jacks. Always use two hydraulic jacks. One should be on each side of the unit opposite each other
and under the unit frame members. Raise and lower the jacks in equal increments to prevent bending of the
Screw Type Stabilizing Jacks. After you have blocked the unit level, the screw type stabilizing jacks should be
tightened to maximum torque.
Retorquing of Nuts and Bolts. You should ensure that all bolts are tightened by torquing the nuts, not the bolt
heads. You should continually retorque throughout the operation of the plant. This should be done especially at
critical points and during the initial operation to assure proper seating and to prevent parts from loosening and
getting out of adjustment. Any adjustments required, such as movement of trunnion wheels on the trunnion shaft,
should be made during the first hours of operation.
Jaw plates and roll shells are held in place by wedges which are secured by keeper bolts. The wedges must be
driven "home" with a sledge hammer while constantly applying torque with the wrench to achieve proper
Visual Inspection. You should visually inspect the plant continuously from ground level and from the platform
and walkways to promptly detect any misadjustment or loss of adjustment to prevent damage and eventual
Adjustments. You should make and check all adjustments with the components operating while empty and
recheck while loaded with aggregate.
You should refer to the appropriate technical manual for complete operating
Training. You should train all personnel assigned to operate the plant. During this training period the
importance of site preparation, set-up, maintenance, and safety should be emphasized. You should keep the
proper tools, materials, and manuals at the site. A high rate of aggregate production should not be expected until
personnel become familiar with the equipment.
Tools. Military crushing and screening plants are of necessity more compact than equivalent commercial plants.
This is because they must be transportable by highway, rail, or air. This compactness reduce clearances at many
vital maintenance points which, together with the high torque required on most nuts and bolts, makes high quality
proper tools an absolute necessity. The use of proper tools will also reduce maintenance time as less disassembly
will be required. The tools used in maintenance and assembly of the plant are included in the mechanic's tool set
which is TOE to the organization, and the basic issue items that are incorporated with each plant.
Maintenance. Equipment maintenance has a direct effect upon equipment operation. In order to accomplish a
construction mission in the minimum possible time, your construction unit must have and maintain a high state of
maintenance. Improper organizational maintenance is the cause of many equipment failures. These failures
normally occur when the equipment is used the hardest or when it is needed the most. More operating time at the
sacrifice of maintenance will result in lower overall production in the long run.