Phases korrigier end, reflecting zone plate for focusing of microwaves.

摘要

A cam actuator for selectively moving cam elements (23) between distinct operative positions, the actuator including a series of adjacent pistons (36-38) arranged side by side along the axial line of displacement, stop means for limiting the axial stroke of each piston in the direction of extension, each piston co-operating with adjacent pistons such that displacement of a given piston in the extend direction causes the remaining pistons located downstream of the given piston to be displaced in the extend direction by the stroke length undergone by the given piston.