 Balanced-arm lamp

A balanced-arm lamp, sometimes called a floating arm lamp, is a lamp with an adjustable folding arm which is constructed so that the force due to gravity is always counteracted by springs, regardless of the position of the arms of the lamp.Many lamp brands (such as the Anglepoise, originator of the concept, and Luxo L-1) as well as other devices, such as drawing boards, use this principle.