Vacuum lift device.

摘要

An object is to properly maintain an object to be lifted at a desired height. A lift tube 1 which is able to contract and expand in an upward and downward direction, and a lift tube expansion control valve 30 controlling the opening areas of the atmospheric openings 28, 29 of the lift tube 1 are provided. A hovering control valve 48 controlling the flow area between the second atmospheric opening 29 and the interior of the lift tube 1 is provided. The lift tube expansion control valve 30 is normally positioned at a position such that it completely covers the first atmospheric opening 28, and the second atmospheric opening 29 is open to the outside space. At this time, the level of vacuum in the lift tube 1 is adjusted by the hovering control valve 48 so that an object to be lifted is maintained at a desired height. <IMAGE>