Screw Propeller, Patent Model

Description
This patent model represents Jackson Harrington's 1875 design for a "propeller-wheel," which improved upon a propeller he and a colleague invented in 1866.
The Patent Office issued over 800 patents for paddle wheels, propellers, and other propulsion apparatus between 1790 and 1873. About 250 of these were propellers.
Jackson Harrington and Francis Caffrey, then of New Haven, Connecticut, patented a six-bladed propeller design in 1866 that aimed to "enlarge the driving-surface" of the propeller "by means of parallel blades with an aperture between them." Nine years later, Harrington, now living in the town of Groton Bank outside New London, patented an improvement to his and Caffrey's earlier design. The new propeller still had six blades, but instead of grouping them in pairs around a single hub, he specified that three go on a forward hub and three on a rear hub. This arrangement aimed to make the propeller easier and cheaper to manufacture. Harrington further refined the shape of the blades and their positions relative to each other, toward the end of reducing friction between propeller and water.
Harrington, born in 1827, and Caffrey, born in 1828, were both machinists.
Location
Currently not on view
Date made
1875
patent date
1875-04-13
patentee
Harrington, Jackson
inventor
Harrington, Jackson
Associated Place
United States: Connecticut, New Haven
Physical Description
brass (overall material)
Measurements
overall: 1 1/2 in x 3 in; 3.81 cm x 7.62 cm
ID Number
TR.308561
catalog number
308561
accession number
89797
patent number
162,063
subject
Patent Models
See more items in
Work and Industry: Maritime
America on the Move
Transportation
Data Source
National Museum of American History

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