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.
- Bolt tensioners are devices designed to apply a specific tension to a bolt. The device may be either removed once the actual nut is threaded into place, or left in place, in the case of a hydraulic nut.
- The belt or chain tension on a single-speed bicycle can be maintained by either setting the fixed horizontal position of the rear sprocket or the front chainring horizontally, or by a separate tensioner that pushes perpendicular to the chain with either a fixed position or spring tension.
- The serpentine belt and the timing belt or chain on an automobile engine may be guided by an idler pulley and/or a belt tensioner, which may be spring-loaded, hydraulic, or fixed.
- A marine riser tensioner is a device used on an offshore drilling vessel which provides a near constant upward force on the drilling riser independent of the movement of the floating drill vessel.
- A guideline tensioner is a hydropneumatic device used on an offshore drilling rig that keeps a positive pulling force on the guidelines from the platform to a template on the seabed.
- Overhead electrical wires may be kept in tension by springs or weights.
- Conveyor belts
- Chair lift and gondola lift cables
- Certain wood trusses, such as the beam tensioner truss picture below.
- Fencing made of wire, such as electric fences, barbed-wire fences, and chainlink fences often include tensioning devices to keep them taut.
- Belt sanders have a mechanism, often a spring-loaded idler drum, to apply the proper tension to the sanding belt, which can be released to allow for changing belts.
Track tensioner on a Churchill Tank
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- "Homelite 18" Gas Chain Saw Review". Gadget Review. September 1, 2011. Retrieved 2014-12-29.
- "Timber Connectors". MiTek. 2011. Retrieved 2014-12-29.
- "Strap Brace Tensioners". Pryda. 2014. Retrieved 2014-12-29.
- "Belt Sander" (PDF). ShopSmith. Retrieved 2013-12-30.