| 摘要 |
<p>A step stool comprising a base having a top surface adapted to be located upwardly from the ground; an aperture through the top surface; an elongated support; a platform on the support, the support being movable longitudinally through the aperture between a collapsed position in which the platform lies on the top surface and an extended position in which the platform is spaced upwardly from the top surface; and engagement means on the support operative to engage the surround of the aperture on one side of the aperture with the support bearing against the surround of the aperture on the opposite side of the aperture, to retain the support in its extended position against downward force exerted on the platform.</p> |
