Corliss' Patent Model of a Steam Engine Cut-Off Valve – ca 1859
date: label: date made
content: 1859
label: patent date
content: 1859-07-05
name: label: inventor
content: Corliss, George H.
notes: label: Description
content: This model was filed with the application to the U.S. Patent Office for Patent Number 24,618 issued to George H. Corliss of Providence, Rhode Island on July 5, 1859. The patent was for an improved cut-off valve gear for steam engines. With this patent Corliss was seeking to improve the ability of the gear to operate at higher speeds than were possible with his earlier patent for a similar device. The patent represents the first valve gear to combine all the elements of what would become known as the typical, and very popular, Corliss engine. These include a detachable inlet valve link, variable timing wedge, a spring for closing the inlet valve, a dash pot to prevent jarring in closing the valves, and rotating valves.
label: Description
content: Corliss' design provided a means of adjusting the point in the power stroke of the engine’s piston at which high pressure steam being fed to the cylinder was cut off. This was desirable as power was extracted from the expansive force of the steam after the valve closed. This saved fuel by avoiding continuing use of high pressure steam.
label: Description
content: A primary feature of the patent is the mechanism shown at the top of the image of the model. It is the small steel piece of metal with a hook at its right end which engages a similar hook on the steam inlet valve stem extending to the right. The two hooks remain engaged by spring pressure until the valve stem is moved to the point that the inclined brass plate at the left overcomes the spring tension. The brass plate is moved laterally to change the point at which the toe and tooth disengage. As soon as they disengage another spring forces the inlet valve stem to close the valve.
label: Description
content: Corliss was a prolific inventor of steam technology in the middle 1800s and was the founder of the Corliss Steam Engine Company. His engines were used worldwide, and his designs were adopted by other engine manufacturers.
label: Description
content: The patent model is constructed of brass and mahogany. All of the key elements of the patent are illustrated by the model. In the image of the back of the model can be seen a hand crank for demonstrating operation of the valves which are also shown. Diagrams showing the complete design of the patent can be found in the patent document online at the United States Patent and Trademark Office website, www.uspto.gov.
place: label: place made
content: United States: Rhode Island
label: associated place
content: United States: Rhode Island, Providence
topic: label: Subject
content: Patent Models
label: Subject
content: Steam Engines
setName: label: See more items in
content: Work and Industry: Mechanical and Civil Engineering
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content: Engineering, Building, and Architecture
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content: Patent Models
label: Exhibition
content: Power Machinery
label: Exhibition Location
content: National Museum of American History
publisher: label: Related Publication
content: Frank A. Taylor. Catalog of the Mechanical Collections of the Division of Engineering United States National Museum, Bulletin 173
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: MC.308648
label: catalog number
content: 308648
label: accession number
content: 89797
label: patent number
content: 24,618
objectType: label: Object Name
content: engine, steam, valve gear, model
label: Object Name
content: engine, steam, valve gear, patent model
label: Object Name
content: patent model, valve, steam
physicalDescription: label: Measurements
content: on black wood block: 13 in x 17 in; 33.02 cm x 43.18 cm