| 摘要 |
<p>The breaker tool is associated with a movable abutment device formed by an abutment tool (20) rigidly connected in keyed engagement to the matrix (14) around the edge of the aperture (16,18) and having a support or abutment surface (24, 25) which can be inclined to the connecting area. The connecting area can be formed by a rear cut socket groove in the matrix around the opening (16) and by a coupling rib engaging therein. The breaker tool can be a pressure pin or forked member with roughened surface produced mechanically, chemically or electrically.</p> |
