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Patent:US2231906

Patent:	US 2231906
Title:	Calculating span clearance rule
Date:	18.02.1941
Place:
Country:	USA
Person:	Harold Hansen Carl
Company:	American Telephone and Telegraph
Internal Links:
Keywords:
Link to the patent office: (without guarantee)	US2231906 (espacenet),  US2231906 (uspto)

Aus der Patentschrift US2231906

• DATUM: 18.02.1941
• TITEL: Calculating span clearance rule
• PERSON: AMERICAN TELEPHONE TELEGRAPH