| 摘要 |
<p>HEIGHT ADJUSTABLE CHAIR BASE The specification discloses a compact, easy to assemble, height adjustable chair base in which a column telescopically received within a hub tube includes a spring and nut assembly located within the bottom of the column and carried on a threaded post fixedly secured and projecting upwardly within the hub tube. A spring housing is rotatably carried within the column and the top abuts against an abutment shoulder located within the column. The spring is located within the spring housing and both the spring and spring housing bear down on a washer which in turn bears down on the nut. The column includes portions extending around and below the nut, includes detent means located on the column below the nut which disengage the nut when a person sits on the chair, but which is biased upwardly towards engagement with the nut by the action of the spring when the chair is unoccupied. When the chair is unoccupied, rotation of the chair will cause the nut to rotate upwardly or downwardly on the threaded post.</p> |
