| 摘要 |
The chair base includes a hub having a central axis and a number of legs attached to and radially extending from the hub. A bore extends concentrically along the axis through the hub defining an interior wall within the hub. The interior wall includes an upper conical wall portion extending between a circular first upper edge and a circular first lower edge. The first upper edge has a larger diameter than the first lower edge such that the conical wall portion tapers inwardly and downwardly. The interior wall also includes a lower wall portion disposed below the upper conical wall portion which extends between a circular second upper edge and a circular second lower edge. The second upper edge of the lower wall portion has a diameter which is smaller than the diameter of the first lower edge of the upper conical wall portion. A annular wall portion extends between the second upper edge of the lower wall portion and the first lower edge of the conical wall portion. The annular wall forms an inwardly extending step for engaging the bottom end of the column when the column is inserted into the bore and thereby prevents the column from moving downwardly through the bore past a predetermined point during use. |
