| 摘要 |
A mine roof mechanical anchor having the usual expansion shell and tapered nut is fitted with a bail having legs secured to the shell and a medial portion extending over and contacting the nut, maintaining the latter in assembled relation with the shell, and having an opening aligned with and slightly smaller than the threaded opening in the nut. Bail extension structure, having a pair of legs attached to the legs of the first bail and a medial portion aligned with and spaced from that of the first bail, provides a means of breaking the casing and mixing the contents of a standard resin cartridge inserted in a bore hole in a mine roof ahead of the anchor and threaded bolt or rebar on which it is supported. The anchor and associated structure are rotated together with the roof bolt or rebar due to interference thereof with the smaller opening in the medial portion of the bail. After the resin cartridge is broken and contents mixed, rotation is stopped for a few seconds to allow the resin to begin to set and restrain further rotation of the anchor. When rotation is resumed the bolt or rebar is forced through the opening in the bail, but the tapered nut is not advanced to expand the shell until the end of the bolt or rebar contacts the medial portion of the bail extension structure. The bolt may then be tensioned and is anchored mechanically and by the hardened resin.
|
