Percussive rotary rock drilling tool
作者： Beck Robert Wm
DOI:
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摘要:
lens.org 参考文章(4)
William R Postlewaite, Turbine-impact drill ,(1948)
Walter J Bielstein, Rotary percussion drilling device ,(1952)
George P Wagner, Fluid motor for driving rotary tools ,(1947)
Ragland Douglas, Shock absorbing drill collar ,(1954)