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US Patent: AI7
Canal Lock Gate
Patentee:
David Wilkinson (exact or similar names) - Cohoes, Albany County, NY

USPTO Classifications:
405/86

Tool Categories:
transportation : canals : locks

Assignees:
None

Manufacturer:
Not known to have been produced

Witnesses:
Unknown

Patent Dates:
Granted: Apr. 24, 1838

Reissue Information:
Reissue of 9,040X (Aug. 17, 1835)

Patent Pictures: [ 1 | 2 | 3 ]
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Description:
In the United States, the term "Additional Improvement Patents" refers to a specific, historical category of patents used between 1837 and 1861. Under the Patent Act of 1836, an inventor could add improvements to their already existing patent rather than filing an entirely new application.

AI (Additional Improvements) patents were issued between 1836 and 1861 and only 318 were ever issued.

Only the patent drawing is available.

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