Telescoping (mechanics)

Showing the telescopic principle, an object collapsed (above) and extended (below), providing more reach.

Telescoping in mechanics describes the movement of one part sliding out from another, lengthening an object (such as a telescope or the lift arm of an aerial work platform) from its rest state. In modern equipment this is often done by hydraulics, but pulleys are used for simpler designs such as extendible ladders & amateur radio antennas.

See also Telescopic cylinder.