CHAIN LUBRICATION BEST PRACTICES FOR DRIVES AND CONVEYORS

A chain is a series of traveling journal bearings with a means to engage the teeth of a sprocket and transmit force and motion. Because each chain joint is a bearing, proper lubrication is essential to obtain the maximum service life from a chain drive or conveyor.

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Chains for Drives

The three most common types of chains used for drives are: precision roller chain, covered by American National Standard ASME B29.1; silent (inverted-tooth) chain, covered by ASME B29.2; and engineering steel offset sidebar chain, covered by ASME B29.10.

Roller chains are produced in 0.25 through 3.0-inch pitch and are used for a wide variety of drives in the slow to high-speed range. Silent chains are produced in 0.375 through 2.0-inch pitch, run smoother than roller chains, and are used mainly in high-speed drives. Engineering steel chains are made in 2.5 through 7.0-inch pitch and are used mainly in slow-speed drives.

Chains for Conveyors

Both precision roller chains and engineering steel roller chains are commonly used in slat, apron, pusher and crossbar conveyors. Welded steel chains are widely used in scraper and drag chain conveyors. Forged link chains are frequently used in overhead trolley and floor conveyors.

Precision roller chains, engineering steel roller and roller less chains, cast chains, polymeric chains, flat top chains and silent chains are used in plain chain and carrier chain conveyors. Space limitations will permit covering only a few of the most widely

How Chains Fail

The three most common ways that a chain may fail are tensile, fatigue and wear. In a tensile failure, the chain is overloaded in tension until it is stretched so badly it will not function properly, or it is literally pulled apart. In a fatigue failure, the chain is loaded repeatedly in tension, at a load below the yield strength (the chain is not stretched), until microscopic cracks develop in the link plates or sidebars.