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公开(公告)号:US880140A
公开(公告)日:1908-02-25
申请号:US1906346750
申请日:1906-12-07
Applicant: ELECTRIC CONTROLLER AND SUPPLY COMPANY
Inventor: HASTINGS BENJAMIN
CPC classification number: E21B7/201
公开(公告)号:US880140A
公开(公告)日:1908-02-25
申请号:US1906346750
申请日:1906-12-07
Applicant: ELECTRIC CONTROLLER AND SUPPLY COMPANY
Inventor: HASTINGS BENJAMIN
CPC classification number: E21B7/201