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公开(公告)号：US2072430A
公开(公告)日：1937-03-02
申请号：US75728534
申请日：1934-12-13
Applicant: LESLIE A LAYNE
Inventor： ROCO ALBERT L , VERNON WALTERS WILLIAM
IPC: E21B21/10
CPC classification number: E21B21/10
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