Tensioner

A tensioner is a device that applies a force to create or maintain tension. The force may be applied parallel to, as in the case of a hydraulic bolt tensioner, or perpendicular to, as in the case of a spring-loaded bicycle chain tensioner, the tension it creates. The force may be generated by a fixed displacement, as in the case of an eccentric bicycle bottom bracket, which must be adjusted as parts wear, or by stretching or compressing a spring, as in the case of a spring-loaded bicycle chain tensioner; by changing the volume of a gas, as in the case of a marine riser tensioner; by hydraulic pressure, as in the case of a hydraulic bolt tensioner; or by gravity acting on a suspended mass, as in the case of a chair lift cable tensioner.

Spring-loaded overhead line tensioner

Gravity overhead line tensioner

Chain tensioner in an automobile engine

Serpentine belt on belt tensioner in an automobile engine

Adjustable, fixed-position belt tensioner in an automobile engine

Drum tensioner

Conveyor belt tensioner

Chair lift cable tensioner

Chain tensioner for a bicycle with an internal gearbox

Chain tensioner for a single-speed bicycle

Bicycle chain tensioned without a dedicated tensioner mechanism

Traditional Finnish frame saw with wooden frame, loggers' tool before cross-cut and chain saws till 1960s

Marine riser tensioner

Beam tensioner truss

Chainlink fence tensioner

Track tensioner on a Churchill Tank

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Wikipedia