| 摘要 |
<p>A spindle for working chairs having an adjustable height comprises an inner tube (1) which is slidably inserted in an outer tube (3) and extends therefrom and is adapted to transmit the load from the chair seat to the outer tube. The inner tube (1, 1', 1") is lockable in a plurality of positions relative to the outer tube. The load is transmitted from the inner to the outer tube through a threaded spindle (10, 10', 10") which is coaxial with the tubes and is rotatably mounted in the outer tube (3), and the threads of which engage a nut (8) which is stationary with respect to the inner tube. The threaded connection formed between the nut and the spindle has a pitch which is sufficiently large for the connection not to be self-locking when the nut (8) is moved axially, but still sufficiently small to allow a substantial part of the axial load to be transferred to the threaded spindle (10, 10', 10"). A releasable locking member (18, 18', 18a, 18b) preventing rotation of the threaded spindle (10, 10', 10") relative to the outer tube is provided for locking the telescopic device. The threaded connection is used to provide a spring operated adjustment of the length. For this purpose the outer tube (3) is nonrotatably secured with respect to the inner tube (1, 1', 1"), and a spiral spring (21), i.e. a spring similar to a watch spring, is provided for acting between the outer tube (3) and the spindle (10, 10', 10") for rotation thereof in a direction corresponding to a raising of the seat of the chair.</p> |
