专利名称：ROTARY DRILLING HEAD AND METHOD OF
BREAKING PIPE JOINTS
发明人：VISSER R,US,STEWARD V,US申请号：US42748873申请日：19731226公开号：US3851714A公开日：19741203
摘要：A rotary driving head for powering a drill string having a splined plunger withinits powered spindle which is remotely controlled for selectively rigidly interconnectingthe spindle and a joined section of drill pipe so that the latter can be unscrewed from itslower coupling by simply reversing the rotation of the rotary head.
申请人：MISSION MFG CO,US
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