MAINTENANCE CHECKLIST INSPECTION AND PREVENTION
Regardless of the application, all chain systems should be inspected on a regularly scheduled basis for worn, damaged or broken parts, possible interference by other system components, and proper lubrication. Normal maintenance procedures can prevent most of the conditions described below. Carefully inspect roller chain drives on the same schedule as associated equipment.
Sprocket Misalignment: Wear on the sides of sprocket teeth generally indicates improper installation of sprockets and/ or shafts. If shafts are out of parallel or not in the same plane, non-symmetrical wear will appear on sprockets or chain rollers. After proper alignment is made, retighten set screws in sprocket hubs. Chain Wear and Elongation: Normal wear will cause some increase in chain length. However, if a sudden increase in elongation occurs, look for severe wear on the tips of sprocket teeth. This may be caused by any of the following: excessive loading or shock loading, displacement and/or wear in bearings, displacement of takeups, or under-designed drive. Elongation of 3% or more may be an indication that chain and/or sprockets should be replaced. Before replacing chain or sprockets, recalculate initial drive design. Check chain for broken parts. Check chain tension if there is too much accumulated slack in the drive. Link Plate Wear: Wear on edges of outer sides of link plates may be caused by chain contacting a case or fixed object. Remove or relocate fixed object. Readjust chain properly. Broken Chain Parts: Generally caused by an overload drive, extreme misalignment, excessive elongation causing chain to jump sprocket teeth, heavy shock, improper drive design geometry, or foreign objects. Recalculate initial drive design and make necessary corrections. Inspect sprockets and shafts for proper alignment or looseness.
Excessive Noise: Can be caused by broken links and chain rollers, extreme misalignment, elongation, chain jumping sprocket teeth, loose sprockets, broken teeth, accumulation of dirt packed into the chain or sprocket teeth, interference by foreign objects, or contacting a fixed object. Check for worn, broken, or missing parts. Check alignment of shafts and/or sprockets. Excessive Vibration: Unbalanced rotating parts, broken or missing rollers, too much chain slack, loose or misaligned sprockets or shafts. Inspect chain and drive equipment. Replace or readjust as needed. Improper Lubrication: Light or dark brown discoloration of pin-bushing joints and connecting link pins, or brown-red oxide color in oil may indicate chain is not dipping into the oil reservoir, or drip lubricator or spray is plugged. Carefully clean and dry chain, immerse in oil, and reinstall. Change oil in chain case and flush case. Determine that oil supply is adequate and unimpeded. Suggested Replacement Procedures: Chain parts should never be altered or tampered with by makeshift repairs and/or with parts or components which have not been authorized by the company.
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