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US Patent: 137,765
Improvement in hydraulic jacks
Patentee:
Richard Dudgeon (exact or similar names) - New York, NY

USPTO Classifications:
417/443, 417/552, 60/481

Tool Categories:
material handling : jacks : hydraulic jacks

Assignees:
None

Manufacturer:
Richard Dudgeon - New York, NY

Witnesses:
John F. Dettmar
Walter Buchanan

Patent Dates:
Applied: Feb. 12, 1873
Granted: Apr. 15, 1873

Patent Pictures:
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Vintage Machinery entry for Richard Dudgeon
Dudgeon v. Watson
Description:
This patent provides an improved method of allowing the jack to be lowered by providing a mechanism to allow the hydraulic fluid to flow around the ingress valve rather than through it. This improvement made the lowering mechanism more robust and less prone to failure where the jack would get stuck in the raised position.

A lawsuit, Dudgeon v. Watson, was heard in the Southern District Court of New York on December 18, 1886, and involved this patent and the later patent 297,975. The defence argued that patent 6,274, for a steam pump, anticipated this patent, an argument the court rejected because the object of Dudgeon's invention was different. The judge's elitism is telling: "It required a creative faculty, not usually found in the slow, non-perceptive brain of the skilled workmen, to construct the hydraulic jack of 1873 from the steam-pump of 1849." More convincingly, the judge pointed out that for 24 years no-one else had though to apply the steam-pump mechanism to the hydraulic jack, and that confirms that Dudgeon's invention was non-obvious. The decision went against Watson in infringing on both of the Dudgeon patents.

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