| 摘要 |
<p>A gravity-driven lumbar expander comprises two shafts (1, 2) with half-shells (3, 4) oscillating thereon. One end of each of the shafts (1, 2) is, directly or indirectly, rigidly fastened to a slide bar (5) supported by a bearing column (10), and at least one end of the slide bar (5) receives a slider (7) which is rotatably supported with respect to said slide bar (5), acts as a support for the end of one of said shafts (1, 2) and is connected via a traction mechanism to the stationary portion formed by the slide bar (5). This mechanism is preferably a rope of which one end is attached to the slider (7) while the other is attached to a winch barrel whose shaft (13) is, directly or indirectly, rigidly fastened to the slide bar (5). The slider (7) is automatically urged away from the bearing column (10) by a spring in the absence of a tensile load on the rope (19).</p> |
