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.

Applications

*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.

*The chain tension of a chainsaw may be adjusted with a chain tensioner.

*A marine riser tensioner is a device used on an offshore drilling vessel that 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.

Gallery

File:Overhead line tensioner 012.JPG, Spring-loaded overhead line tensioner
File:Overhead line tensioner 003.JPG, Gravity overhead line tensioner
File:Nockenwellenantrieb.jpg, Chain tensioner in an automobile engine
Image:Tensioner.jpg, Serpentine belt on belt tensioner in an automobile engine
File:Tendeur courroie alternateur automobile.jpg, Adjustable, fixed-position belt tensioner in an automobile engine
File:Seamus O Kane Band Tensioner System Bodhran.JPG, Drum tensioner
File:Conveyor belt tensioner - geograph.org.uk - 1485359.jpg, Conveyor belt tensioner
File:Bullwheel and counterweight in tENSION TERMINAL, LOOKING southeast. - Mad River Glen, Single Chair Ski Lift, 62 Mad River Glen Resort Road, Fayston, Washington County, VT HAER VT-38-42.tif, Chair lift cable tensioner
File:Pinion P1.18 mounted.jpg, Chain tensioner for a bicycle with an internal gearbox
File:Planet_X_Stealth_Pro_Track_Bike_I.jpg, Chain tensioner for a single-speed bicycle
File:Single speed conversion.jpg, Bicycle chain tensioned without a dedicated tensioner mechanism
File:OldFramesaw-cut-out.png, Traditional Finnish frame saw with wooden frame, loggers' tool before cross-cut and chain saws till 1960s
File:Riser_Tensioner.jpg, Marine riser tensioner
File:Beam Tensioner Truss.jpg, Beam tensioner truss
File:Cric-tenseur.jpg, Chainlink fence tensioner
File:Track Tensioner on a Churchill Tank.jpg, Track tensioner on a Churchill Tank

See also

* Turnbuckle
*Torque wrench

References

{{reflist

External links

Hydraulic Tensioning Glossary

Drilling technology
Hardware (mechanical)