| 摘要 |
An adjustable support device comprising a first elongated member having an upper end, a second elongated member having an upper end, a mechanism for connecting the first member to the second member such that the upper ends of the first and second members are vertically, adjustably movable in response to movement of the first elongated member with respect to the second elongated member, and a ratch connected between a first point located on the first member and a second point located on the second member for releasably securing the first and second points in spaced relationship and for selectively varying the spacing between the first and second points. |
