7. Manipulation of Chains
Symptom The roller is opening up.
Remedy Reduce the load, provide adequate lubrication, remove any large steps in the rail. Reduce the load. Provide adequate lubrication.
Possible Causes Excessive load.
Excessive load.
The roller or bushing is split (falling off).
Increase the number of teeth. Decrease the speed.
The number of teeth is too few with respect to the conveyor speed.
Increase the lubrication, improve loading conditions, and replace the chain with a new one.
Excessive load or inadequate lubrication.
The roller is becoming hour- glass shaped.
Correct or replace the rail.
Excessively worn rail.
The chain sticks and slips. (This can be caused by a combination of many prob- lems. Therefore, the listed remedies may not solve the problem.)
Lubricate the chain and clean the rail. Lubricate with Tsubaki oil. Change to a bearing roller chain.
Change the rolling friction coefficient of the chain.
The conveyor speed is too slow.
Increase the speed.
Insufficient rigidity in the frame. The conveyor chain is small compared to the device.
Increase the frame rigidity; increase the chain model number. Decrease the slack in the drive roller chain.
The force of friction is excessively large.
Lubricate the chain. Change to a bearing roller chain.
The machine is too long.
Divide the conveyor system into sections to decrease the length.
Inconsistent speeds due to movement along a polygon-shaped path.
Use a 12- or-more-toothed drive sprocket.
Excessively worn chain.
Replace both the chain and sprocket.
Excessive wear of the sprocket teeth valleys and drive sides.
Insufficient number of teeth.
Increase the number of teeth.
ABF chain (no rollers) is being used.
Change to an RF chain (with rollers).
The hardness of the teeth is insufficient with respect to the load and conveyed material or foreign particles.
Use a sprocket with hardened teeth or changeable teeth.
Replace the chain or sprocket with one that is of the correct size.
The chain and sprocket do not match.
Excessive wear of the inside link and pin on one side of an NF block chain or BF chain (no roller).
Increased internal tension when meshing with the sprocket.
Attach the supporting block to the sprocket. Reduce the load. Lubricate the chain and sprocket.
Sudden fracture of the link plate.
Excessive load.
Eliminate causes of the overloading. Install a safety device (for example, Shock Relay). Increase chain size.
Weakening of chain caused by excessive wear or corrosion.
Replace with new part. Install a cover to protect the chain. Periodically lubricate chain. Select a chain with the proper specifications for the application. Check and correct the installation. Excessively worn chain or sprocket. Check if the chain and sprocket match, and correct as necessary.
The link plates are pressed outward by the sprocket.
Excessive load or excessively large repetitive load.
Crack in the link plate. (1) Fatigue breakage.
Eliminate overloading or large repetitive loads.
The factor of safety is not sufficient.
Increase the size or specifications of the chain to increase the factor of safety. Replace with a new chain. Eliminate overloading or large repetitive loads; increase the chain size to increase the allowable load of the attachment.
Repetitive load on attachment.
Figure 7.19 (ii) Troubleshooting Large Pitch Conveyor Chain
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