TGW NBS 30 Series, Installation, Operation & Maintenance Manual

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NBS IOM
36
Repair Procedures
WARNING
Do not perform maintenance on the conveyor until the startup controls are locked out and cannot be turned on by
any person other than the one performing the maintenance. If more than one member of a crew is working on the
conveyor, EACH CREW MEMBER MUST HAVE A LOCK ON THE POWER LOCK OUT. The air pressure must
be turned off to the work areas.
Make sure personnel are clear of all conveyor equipment before restarting the system. Do not use gasoline or
kerosene for cleaning. Use nonflammable solvent only.
CHAIN & SPROCKETS
Lubrication of roller chains is essential to effectively minimize metal-to-metal bearing contact of pin-bushing joints
in the chain. Oil should be applied to outside and inside plate edges, since access to the pin-bushing area is
possible only through clearances between the outside plates and the inside plates. Oil applied on the center line
of the rollers cannot reach pin-bushing joints.
Chain drives should be protected against dirt and moisture. Oil supply should be kept free of contamination. A
good grade of non-detergent petroleum base oil is recommended. Heavy oils and greases are generally too stiff
to enter and fill the chain joints. The following table indicates the proper lubricant viscosity for various surrounding
temperatures.
Temperature
Degrees F Recommended
Lubricant
20 to 40 SAE 20
40 to 100 SAE 30
100 to 120 SAE 40
120 to 140 SAE 50
Inspection includes:
1. Lubrication check for dirt, grit, or chips and clean if necessary by soaking chain in nonflammable cleaning
solvent
2. Sprocket alignment (see following text)
3. Wear on the inner surfaces of the roller chain link plates
4. Sprocket tooth wear
5. Chain tension (see following text)
6. Set screw tightness (5/16-18 at 13 ft./lbs. & 1/4-20 at 6 ft./lbs.)
SPROCKET ALIGNMENT
1. Loosen sprocket.
2. Align loose sprocket to the other by laying a straight edge across their faces or along the chain.
3. Retighten the loose sprocket.
CHAIN TENSION
Chain should be checked for excessive slack, if the chain is running close to the tips of the sprocket teeth. This
can be checked by lifting the chain away from the large sprocket, making sure the chain is in mesh with the
sprocket teeth. Excess clearance is conclusive evidence that the chain has elongated in pitch and no amount of
tension adjustment will keep it properly meshed with the sprocket teeth. Continued operation will quickly destroy
the sprocket teeth which otherwise may be good. If the sprocket is still serviceable, replace the chain.
TENSION ADJUSTMENT
1. Loosen mounting bolts of tension.
2. Increase tension up to 1/2" of total slack (1/4" each way of center).
3. Turn adjusting bolts on gearbox plate or move gearbox in mounting slots until there is 1/2" total chain slack.
4. Retighten all bolts after checking alignment.
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