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公开(公告)号:US2281750A
公开(公告)日:1942-05-05
申请号:US33341740
申请日:1940-05-04
Applicant: CLARKSON RALPH P
Inventor: CLARKSON RALPH P
IPC: E01B9/48
CPC classification number: E01B9/483
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公开(公告)号:US2252116A
公开(公告)日:1941-08-12
申请号:US34862040
申请日:1940-07-31
Applicant: CLARKSON RALPH P
Inventor: CLARKSON RALPH P
IPC: E01B13/02
CPC classification number: E01B13/02 , E01B2201/08 , E01B2201/10
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公开(公告)号:US2044060A
公开(公告)日:1936-06-16
申请号:US74086234
申请日:1934-08-22
Applicant: CLARKSON RALPH P
Inventor: CLARKSON RALPH P
IPC: E01B5/18
CPC classification number: E01B5/18
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公开(公告)号:US2271912A
公开(公告)日:1942-02-03
申请号:US19079338
申请日:1938-02-16
Applicant: CLARKSON RALPH P
Inventor: CLARKSON RALPH P
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公开(公告)号:US2203624A
公开(公告)日:1940-06-04
申请号:US6499936
申请日:1936-02-21
Applicant: CLARKSON RALPH P
Inventor: CLARKSON RALPH P
IPC: E01B9/48
CPC classification number: E01B9/486
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公开(公告)号:US2183513A
公开(公告)日:1939-12-12
申请号:US6594536
申请日:1936-02-27
Applicant: CLARKSON RALPH P
Inventor: CLARKSON RALPH P
IPC: E01B9/48
CPC classification number: E01B9/486
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公开(公告)号:US2142495A
公开(公告)日:1939-01-03
申请号:US15629237
申请日:1937-07-29
Applicant: CLARKSON RALPH P
Inventor: CLARKSON RALPH P
IPC: B61K3/00
CPC classification number: B61K3/00
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