Engineering Steel Chain Drives

Engineering steel chain drives are especially suited for heavy-duty apphcations.The normally offset sidebar chain (Fig. 5.87) can handle speeds up to 1000 ft/min (305 m/min) and power... 

Eingineering steel chain has all of the advantages of roller chain listed above, except that engineering steel chain drives tend to be somewhat noisiCT than roller chain drives. That is because of the additional clearances built into engineering steel chains and the pitch-line clearance usually provided in sprockets for engineering steel chain drives. However,... 

The sprocket tooth form for engineering steel drive chains is specified in the ASME B29.10 standard. A drawing of the tooth form and the equations for computing the main dimensions are shown in Figure 4-36. It differs from the tooth form for roller chain in that the pitch line clearance and bottom diameter are slightly smaller than the theoretical root diameter. These differences permit the use of a less precisely made tooth form for engineering steel drive chains than the machine-cut tooth form for roller chains. Engineering steel chain drives are often operated in locations where mud, dirt, ore, rock dust, etc. get into the chain. These drives are often exposed to the weather. Pitch line clearance and the undercut bottom diameter both help provide proper chain-sprocket action under such adverse conditions. 

GENERAL ENGINEERING STEEL CHAIN DRIVE SELECTION GUIDELINES... 

If the speed is slow (in the drip or manual lubrication range), the small sprocket may have as few as nine teeth. Even then, the chain and sprockets may have more power capacity than cold rolled shafting when the small sprocket has only nine teeth. The small sprocket in a typical engineering steel chain drive should have about 12 teeth. If speeds are high (in the oil stream lubrication range), the small sprocket should have at least 15 teeth. 

As was explained in chapter 3, chains elongate as they wear. Wear elongation is limited to a maximum of about 3% to 6% in most engineering steel chain drives. Elongation appears as sag in the slack span as shown in Figure 6-5. The designer must provide sufficient clearance to prevent... 

Engineering steel chain drives often operate unprotected from the environment and are exposed to more dirt, moisture, and foreign materials than roller chains. Thus, a service factor for environment, shown in Table 6-4, is applied to engineering steel chain drives to compensate for the more adverse environments. 

The designer should select the type of lubrication recommended in the power rating charts or tables. More detailed information on engineering steel chain drive lubrication can be found in chapter 13. 

Idler sprockets for roller and engineering steel chain drives wear in a different way. There is not much pressure on the working faces of the teeth on an idler sprocket. So idler sprockets usually wear at the bottom of the tooth space. A badly worn idler sprocket for roller chain is shown in Figure 15-2. When the tooth space is worn deeply enough, the chain rollers may bind against the tooth tips as they enter and leave the idler sprocket. 

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