One of the most power transmitting component in transportation machines like motorcycles, bicycles, automobiles, conveyors, agriculture machinery and machine tools.

Chain drives are flexible and made of a number of links and it's an intermediate between belts and gears drives. Chains can only be used to transmit power between parallel shafts. Unlike belt drives, chain drives use special toothed wheels called Sprockets.

Chain drives consist of an endless series of chain links, which mesh with toothed sprockets. Chain drives are used to perform three basic functions: transmitting power, conveying materials, and for timing purposes.

Roller Chain

1. Standard Roller Chain

   A standard roller chain is made up of alternate roller links (as shown in the figure below). Roller links consist of two sidebars, two bushings, and two rollers. Pin links have two sidebars and two pins, which are normally riveted.

   

   A standard roller chain is manufactured with all the rollers evenly spaced throughout the chain. The rollers have the ability to rotate when contacting the teeth of the sprocket. A roller chain can be of the single-strand type as shown in Figure. Roller chains operate effectively on drives up to approximately 2,500 FPM (762 meters/minutes).

2. Heavy Series Roller Chain

   A heavy series roller chain has a link plate thickness equal to the next largest pitch standard series chain. This chain is used where space and weight limitations prohibit the use of a larger chain. The heavy series has higher yield strength than standard roller chain and will withstand greater shock loads.

   It is available in single- or multiple strands. Adding the suffix ΑH to standard roller chain numbers indicates a heavy series chain.

3. Multiple Strand Roller Chain

   A multiple-strand roller chain consists of two or more single-strand chains placed side-by-side and joined with pins that extend through the entire chain width. Multiple-strand chains are used to transfer maximum power with the smallest pitch size.

4. Double-Pitch Roller Chain

   This is a double-pitch roller chain, which is similar to a standard chain, except the link plates have twice the pitch of the single pitch chain (as shown in the figure below). Double-pitch drive chain is used in place of standard roller chain when speeds are low, loads are light, and center distances are excessively long.

   

   Double-pitch chain has the same diameter pins and rollers, the same width rollers, and the same thickness of link plates as a standard roller chain. Double-pitch chain is not manufactured in multiple strand widths.

   The number system for the double-pitch chain is similar to the ANSI standard roller chain number system. The difference is the addition of 2000 to the base ANSI standard number.

Need for Lubrication

• Chain drive requires lubrication for six purposes.
• To resist wear of the pin-bushing joint
• To cushion impact loads.
• To dissipate any heat generated.
• To flush away foreign materials
• To lubricate chain-sprocket contact surfaces
• To retard rust or corrosion