发明名称 ROCK DRILLING METHOD
摘要 A rock drilling method according to which the drill is subjected to successive axial strikes and is rotated around its longitudinal axis. The direction of rotation is repeatedly reversed after the drill has rotated at least one revolution in one direction.
申请公布号 ZA7704637(B) 申请公布日期 1978.06.28
申请号 ZA19770004637 申请日期 1977.08.01
申请人 TAMPELLA OY AB 发明人 ANTTILA A
分类号 E21B3/025;E21B6/00 主分类号 E21B3/025
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