Column unit for chair

Abstract

The present invention relates to a column unit for a chair, wherein the column unit for a chair is compact and can improve durability against lateral forces. The present invention relates to a column unit for a chair, in which the height thereof is controlled by upward and downward movements of a spindle assembly, wherein the column unit comprises: an outer pipe comprising an inclined portion of which the diameter gradually becomes larger as it approaches a front end thereof; an inner pipe which is inserted into the outer pipe to form a space portion between the inclined portion and the inner pipe; and a spindle guide which is inserted into the inner pipe to guide the upward and downward movements of the spindle assembly.

1 . A column unit for a chair to adjust a height of the chair by moving a spindle assembly upward or downward within the column unit, the column unit comprising:
 a cylindrical outer pipe;   a piston rod inserted within the outer pipe so as to provide a gas fluid passage of a valve within the outer pipe, the piston rod having an exposed end portion fixed to a bottom surface of the outer pipe;   the spindle assembly being moved upward or downward when the gas fluid passage is changed by the piston rod;   a spindle guide provided within an upper side of the outer pipe to guide and support an upward or downward movement of the spindle assembly; and   an inner pipe inserted within the outer pipe to define a space between an inclined part of the outer pipe and the inner pipe,   wherein the outer pipe has a gradually increasing diameter toward an end portion of the outer pipe so that the outer pipe has the inclined part, and   the spindle guide is inserted within the inner pipe to guide the upward or downward movement of the spindle assembly.   
     
     
         2 . A column unit for a chair to adjust a height of the chair by moving a spindle assembly upward or downward within the column unit, the column unit comprising:
 an outer pipe including an inclined part having a gradually increasing diameter toward an end portion of the outer pipe;   an inner pipe inserted within the outer pipe; and   a spindle guide installed within the inner pipe to guide the upward or downward movement of the spindle assembly.   
     
     
         3 . The column unit for the chair as claimed in  claim 1 , wherein the outer pipe has a linear part extending by a predetermined length from the inclined part. 
     
     
         4 . The column unit for the chair as claimed in  claim 1 , wherein the outer pipe has an engagement jaw formed at an inner portion of an end portion of the outer pipe,
 the end portion of the inner pipe is bent outward and is seated in the engagement jaw, and   the outer and inner pipes are secured to each other by pressing their outer surfaces.   
     
     
         5 . The column unit for the chair as claimed in  claim 4 , wherein the inner pipe is provided with at least one through hole formed along the outer periphery of its end portion. 
     
     
         6 . The column unit for the chair as claimed in  claim 1 ,
 wherein the inner pipe has an engagement protrusion formed on an inside of the inner pipe, and   the spindle guide has an engagement recess formed on an outside of the spindle guide, into which the engagement protrusion is inserted.   
     
     
         7 . A column unit for a chair to adjust a height of the chair by moving a spindle assembly upward or downward within the column unit, the column unit comprising:
 a cylindrical outer pipe;   a piston rod inserted within the outer pipe so as to provide a gas fluid passage of a valve within the outer pipe, the piston rod having an exposed end portion fixed to a bottom surface of the outer pipe; and   the spindle assembly being moved upward or downward when the gas fluid passage is changed by the piston rod;   a spindle guide provided within an upper side of the outer pipe to guide and support an upward or downward movement of the spindle assembly,   wherein the outer pipe has a gradually increasing diameter toward an end portion of the outer pipe so that the outer pipe has the inclined part, and   the outer pipe is integrally formed with a securing part being curved at its end portion to encompass the end outer peripheral surface of the spindle guide.   
     
     
         8 . The column unit for the chair as claimed in  claim 7 , wherein the spindle guide has at least one engagement step formed on an outer peripheral surface of the spindle guide. 
     
     
         9 . The column unit for the chair as claimed in  claim 7 , wherein the spindle guide has a seating part circumferentially formed at an upper end portion of the spindle guide, the securing part of the outer pipe being seated in the seating part and the seating part being fixed to the securing part while being engaged with the securing part.