| 摘要 |
<p>A plastic standpipe (38) for an adjustable-height support column (36) for a chair or the like to replace the conventional metal standpipe which supports the height-adjustable device, e.g., a pressurized fluid spring (40). The novel standpipe (38) is a unitary, molded generally tubular member (42) formed of high strength, and preferably low-friction, plastic material. A plurality of circumferentially-spaced, radially-extending support ribs (68), with flexible arc-like members (72) at their inner ends, are formed on the inner wall of the tubular member (42), such that the arc-like members (72) contact the spring cylinder (52) and form a floating circumferential support ring which allows for some lateral freedom of movement of the upper end of the spring cylinder. The interior ribs perform the dual functions of guiding axial movement of the spring cylinder with flexibility during height adjustment and providing sufficient rigidity to the column to support the loads placed on it. A representative composition of the plastic material is fiberglass-reinforced nylon and an impact modifier, such as a ter polymer, comprising ethylene, acrylic acid and maleic anhydride, or a rubber-like polymer. <IMAGE></p> |
