H
I
R
OLLER
- B
ELT
C
ONVEYORS
7. M
AINTENANCE
H
I
R
OLLER
, M
INI
R
OLLER
, L
O
R
OLLER
& H
I
L
IFE
7.2. B
ELT
T
RACKING
G
UIDE
P115506 R3
85
• The normal sequence of training is to start with the return run working toward
the tail pulley, followed by a top run in the direction of belt travel. Start with the
belt empty. After tracking is completed, run the belt with a full load and re-
check tracking.
• Tracking adjustment is done while the belt is running and should be spread
over some length of the conveyor preceding the region of trouble. Permit the
belt to run for several minutes and for at least three full belt revolutions after
idler has been adjusted to determine if additional adjustment is required. If
the belt has over-corrected, it should be restored by moving back the same
idler without shifting additional idlers or rollers.
• Tracking effectiveness of a roll/crown is approximately proportional to the
length of the unsupported span of belt approaching the roll up to a maximum
of approximately 10'. If there is no such span, the tracking effect of the roll is
virtually non-existent. However, such a roll can induce camber (see page 93)
into the belt as it leaves the roll.
Trunking must be installed straight and
level. The tolerance must be less than
+/- 1/8" over the entire length of the
conveyor.
The complete conveyor trunking must be
checked for straightness and squareness
(completed during installation) with a laser
or wire.
The conveyor must be checked for cross
level or twist. A hand held level must be
placed exactly 90° from the centerline of
the conveyor to ensure that the conveyor is level and not twisted.
7.2.1. B
ELT
T
RACKING
- H
I
R
OLLER
& M
INI
R
OLLER
M
ODELS
Remember, squareness of the conveyor must be checked.
Idlers must be checked to make sure that they have not become loose during
shipping or installation. The idlers must be centered and the set screws tightened
on the shafts. Set screws holding the idlers on the outside of the trunking must be
checked for tightness.
There are two pairs of set screws on each idler:
a. There are set screws are on the inside of the trunking holding the stub
shafts on the idler roller.
b. There is a keeper bolt on the end of each stub shaft as shown in Figure
NOTICE
Trunking must be installed straight and level.