TM 5-3895-374-24-2
half the other, but this would be at the expense of increased rolling friction between belt and idlers. For this
reason, all idlers initially should be squared with the path of the belt and only the minimum shifting of idlers used
as training means. If the belt is over-corrected by shifting idlers, it should be restored by moving back the same
idlers, not by shifting additional idlers in the other direction. Do not shift the three idlers before the scale or the
three idlers after the scale.
3.
RETURN ROLLERS
Return idlers, being flat, provide no self-aligning influence as in the tilted troughing idlers. However, by shifting
their axis with respect to the path of the belt, the return roll can be used to provide a constant corrective effect in
one direction. Slots are provided on the return roller brackets for easy adjustment. As in the troughing rolls, the
end of the roll toward which the belt is shifting should be moved longitudinally in the direction of return belt travel to
provide correction.
B.
SEQUENCE OF TRAINING OPERATIONS
Initial installation of conveyor equipment should ensure good alignment of all pulleys, troughing idlers, and return
idler; that is, they should be placed at right angles to the direction of belt travel and should be levelled and
centered on a
straight line.
First movement of the belt should be slow and intermittent so that any tendency of
the belt to run off can be quickly observed and the belt stopped before damage occurs.
Initial movement of the belt will indicate where corrections of the types described are required. The first
corrections must be at points where the belt is in danger of being damaged. Once the belt is clear of all danger
points, a sequence of training operations can be followed.
Since the training will finally complete a circuit, just as the belt does, there is no point at which training can be
started without the possibility of having to make subsequent corrections when returning to the starting point as the
circuit is completed. The best procedure appears to be in starting with the return run and working toward the tail
pulley. This ensures early centering of the belt on the tail pulley so that it can receive its load centrally, which is
highly important.
If the belt is readily troughable so that its running tendencies are not erratic, the training can and should be
completed on the empty belt. Should it tend toward stiffness and erratic running, getting some load onto the belt
as soon as the return run has been straightened up and the belt centered on the tail pulley will help hold the top
run.
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