| 摘要 |
<p>The rectangular frame has four tubes (1) and a diagonal brace (2) which ensures that the frame does not deform during use or storage. One riser (1a) has two stirrup type fixings (3a,3b) with forks having holes to take a locking wedge, the top fixing (3a) being a continuation of the top traverse while the bottom fixing (3b) is offset from the bottom traverse. One of the traverses carries fixing (4)near the riser opposite that carrying the other fixings, the traverse fixing being capable of rotation around the traverse until it is wedged to another frame, but is is prevented from moving laterally by a stop (5).</p> |
