| 发明名称 |
Mining drill steels and methods of making the same |
| 摘要 |
To eliminate or reduce the possibility of fracture in drill steels used in the roof bolting operations in mines the square or hexagonal surfaces of such drill steels or the elements such as couplings or collars which are to be connected to them are machined rather than forged.
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| 申请公布号 |
US6533049(B1) |
申请公布日期 |
2003.03.18 |
| 申请号 |
US19980124780 |
申请日期 |
1998.07.30 |
| 申请人 |
AMERICAN MINE SERVICES |
发明人 |
REIN, SR. TERRY L.;REIN, JR. TERRY L. |
| 分类号 |
E21B17/00;E21B17/04;(IPC1-7):E21B17/00 |
主分类号 |
E21B17/00 |
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