| 摘要 |
<p>The present invention relates to an extension joint for percussive drilling, which joint comprises a male part (1) as well as a female part (10), the male part (1) being intended to be received in the female part (10), the male part (1 ) being pro- vided with an eccentric portion (5) and the female part (10) being provided with a cavity (11). The invention also relates to a rod intended to be included in an extension joint in a drill string for percussive drilling as well as to a method for the manufacture of a part cavity of the cavity in the female part. Characteristic of the extension joint according to the present invention is that a part cavity (14) of the cavity (11) has portions having different radii of curvature (R1. R2).</p> |
