"Positioned as desired in space, the essential Counterbalance LED lamp, with its position variation, suggests the dynamic equilibrium of a sculptural mobile. Equipped with a fluid balancing system using gear wheels, the counterweight compensates for the movements of the long arm and ensures stability of the diffuser."
I like Rybakken's Counterbalance floor model below even better, for the simplicity of the adjustment mechanism. The weight of the head alone leads the two crossways rods to pinch the stem, holding it in place:
Check out more of Rybakken's stuff, including plenty of process shots, here.