Telescopic cylinders are a special design of a hydraulic or pneumatic cylinder which provides an exceptionally long output travel from a very compact retracted length. Typically the collapsed length of a telescopic cylinder is 20 to 40% of the fully extended length depending on the number of stages. [1]Some pneumatic telescoping units are manufactured with retracted lengths of under 15% of overall extended unit length.[2] This feature is very attractive to machine design engineers when a conventional single stage rod style actuator will not fit in an application to produce the required output stroke.[1]Heavy duty telescopic cylinders are usually powered by oil hydraulics, whereas some lighter duty units could also be powered by compressed air.[3]Telescopic cylinders are also referred to as telescoping cylinders and multi-stage telescopic cylinders.

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