Basics
Possible Causes Excessive load or improper lubrication.
Symptom Pin rotates or begins to stick out.
Remedy Replace with new chain. Improve the lubrication or loading conditions. Replace with new chain immediately. Do not weld or reuse the pins. (Dispose of the old chain to be sure that it is not used by mistake.) Also, if the pin head or link plate surface is worn, check the installation.
Operating a chain at high load without proper lubrication can create fric- tion between the pin and bushing, causing the pin to rotate. In this condition, the pin may come out, leading to chain breakage.
Normal
Wear or rust occurs only at the connecting pin in a tension application or similar operation.
Replace the connecting link. If pin wear is exces- sive, replace the chain also. Take special care to properly install the connecting section for devices such as terminators used for tension applications.
Improper initial lubrication at installation.
Figure 7.14 (iii) Pin (Cont.)
Symptom Roller and/or bushing splits and falls off.
Remedy Choose a different chain according to the transmission capacity table. Replace the chain. Provide adequate lubrication according to the operating conditions.
Possible Causes Excessive load or speed of rotation.
Inadequate lubrication.
Fatigue fracture.
Reached the point of fatigue during operation and eventually broke. Impact by the sprocket teeth at a force exceeding the chain’s transmission capacity.
Roller does not rotate.
Abushed chain and not a roller chain is being used.
RS11SS, RS15, RS25, RS35.
Replace with a new chain. Re-inspect the installation and load conditions.
The inner plate is moving inward, or the bushing is cracked. Foreign particles have got- ten between the bushing and roller.
Periodically clean the chain. Install a casing to protect the chain.
Roller is opening up.
Reduce the load. Provide adequate lubrication.
Excessive load.
Roller is becoming hourglass shaped.
Replace with new chain. Improve the lubrication or loading conditions.
Excessive load or inade- quate lubrication.
Figure 7.14 (iv) Bushing / Roller Problems
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