专利名称：Drill collar六级几分过
发明人：James F. Arnold 申请号：US05/763101申请日：19770131
公开号：US04068730A 公开日：
河源恐龙博物馆
十五人打一字
19780117
入党申请书范本专利内容由知识产权出版社提供
摘要：An improved eccentrically weighted drill collar is provided which has a basically stronger structure and stress carrying ability than the eccentrically weighted collar heretofore in field u. The ec
centric weighting is provided by a ries of blind holes extending down one side of the drill collar. The stronger structure and stress carrying ability is afforded by arranging such holes so that they vary in size in a cyclical pattern along the length of the drill collar.
申请人：ARNOLD; JAMES F.
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