Invention Grant
- Patent Title: Abacus
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Application No.: US28377239Application Date: 1939-07-11
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Publication No.: US2228554APublication Date: 1941-01-14
- Inventor: BROWN CHARLES A
- Applicant: BROWN CHARLES A
- Assignee: Charles A Brown
- Current Assignee: Charles A Brown
- Priority: US28377239 1939-07-11
- Main IPC: G09B19/02
- IPC: G09B19/02
Information query
