Patent attributes
The present invention relates to a column unit which connects a chair sheet to a base in which a wheel is installed. The present invention provides a column unit which comprises a base tube having a lower end portion vertically fixed to a base of a chair and having the hollow interior; a spindle having the interior filled with a pressure gas and divided to upper and lower chambers by a piston, an upper end portion of a piston rod being connected to the piston, a lower end portion of the piston rod being rotatably installed at the lower end portion of the inner side of the base tube, the upper and lower chambers are communicated by a bypass, a valve being installed at the bypass; and a guide sleeve installed between the base tube and the spindle and engaged with the spindle to be integrally moved upward and downward together with the spindle.
