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公开(公告)号:US1966318A
公开(公告)日:1934-07-10
申请号:US51660931
申请日:1931-02-18
Applicant: ALUMINUM CO OF AMERICA
Inventor: STEPHENS FORREST H
IPC: E01F9/08
CPC classification number: E01F9/578
公开(公告)号:US1966318A
公开(公告)日:1934-07-10
申请号:US51660931
申请日:1931-02-18
Applicant: ALUMINUM CO OF AMERICA
Inventor: STEPHENS FORREST H
IPC: E01F9/08
CPC classification number: E01F9/578