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公开(公告)号:US2879520A
公开(公告)日:1959-03-31
申请号:US68991357
申请日:1957-10-14
Applicant: HOLLINGSWORTH RICHARD L
Inventor: HOLLINGSWORTH RICHARD L
IPC: E03D1/30
CPC classification number: E03D1/304
公开(公告)号:US2879520A
公开(公告)日:1959-03-31
申请号:US68991357
申请日:1957-10-14
Applicant: HOLLINGSWORTH RICHARD L
Inventor: HOLLINGSWORTH RICHARD L
IPC: E03D1/30
CPC classification number: E03D1/304