Air balance structure

Abstract

An air balance structure that compensates for the weight load of a movable member driven in a straight line along the vertical axis, with a simplified structure and at reduced cost. The box-shaped movable member has an open bottom that accommodates the stationary member therewithin, in which state the movable member is movably supported in the vertical direction by an air bearing created using a gap between the stationary member and the movable member. An air balance chamber that contains pressurized air is formed inside the movable member. After pressure-adjusted air is supplied from the outside to the gap from a jet port through a pipe inside the stationary member, the air flows into the air balance chamber. This flow seals the pressurized air inside the air balance chamber. Pressurized air exhaust is exhausted externally from an exhaust port through a pipe and a flow adjusting device.

Dependencies are inferred from the claim text.