| 摘要 |
<p>PCT No. PCT/AU93/00486 Sec. 371 Date Dec. 21, 1994 Sec. 102(e) Date Dec. 21, 1994 PCT Filed Sep. 22, 1993 PCT Pub. No. WO94/07619 PCT Pub. Date Apr. 14, 1994A hollow bar (3) and a method of manufacturing the hollow bar are disclosed. Typically, the hollow bar is a threaded rock bolt or a drill rod. The hollow bar (3) comprises two or more elongate members (21a, 21b) connected together along the longitudinal edges (41) of the members (21a, 21b). The method comprises rolling the members (21a, 21b) and welding or gluing the members (21a, 21b) together along the longitudinal edges (41) of the members (21a, 21b).</p> |
