
A bar-link chain, also called a block-and-bar chain or a block chain, is a mechanical
drive chain. It is composed of side plates, where each plate straddles one end of a block and is connected to the block with a pin going through a hole at one end of the block. Bar-link chains are simple, and often heavier and less efficient when compared with modern
roller chain
Roller chain or bush roller chain is the type of chain drive most commonly used for transmission of mechanical power on many kinds of domestic, industrial and agricultural machinery, including conveyors, wire- and tube-drawing machines, pri ...
s due to the lack of rolling motion as the chain engages and disengages the
sprocket
A sprocket, sprocket-wheel or chainwheel is a profiled wheel with teeth that mesh with a chain, track or other perforated or indented material. The name 'sprocket' applies generally to any wheel upon which radial projections engage a chain pass ...
s.

However, they have advantages in specific applications, especially where no sprockets are needed, where
strength is a greater concern than efficiency (high loads), and where the chain has special fixtures for holding or engaging a load.
See also
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Drive chain
References
Chain drives
Chains
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