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公开(公告)号:US2077281A
公开(公告)日:1937-04-13
申请号:US7394136
申请日:1936-04-11
Applicant: JOHN STEVENSON
Inventor: JOHN STEVENSON
IPC: B24B27/027
CPC classification number: B24B27/027
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公开(公告)号:US2229196A
公开(公告)日:1941-01-21
申请号:US31682340
申请日:1940-02-01
Applicant: JOHN STEVENSON
Inventor: JOHN STEVENSON
IPC: A01B39/18
CPC classification number: A01B39/18
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