Allen’s Patent Model of Cut-Off Valve for Steam Engines – ca 1841
date: label: date made
content: 1841
label: patent date
content: 1841-08-21
name: label: inventor
content: Allen, Horatio
notes: label: Description
content: This model was filed with the application to the U.S. Patent Office for Patent Number 2,227 issued to Horatio Allen of New York, New York on August 21, 1841. The patent was for an improved design for the mechanism controlling the inlet valve of a steam engine. Allen’s 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 continuous use of high pressure steam.
label: Description
content: The image of the model shows a cross section of the steam cylinder at the right with the piston rod and connecting rod extending to the left to the crankshaft. The steam inlet valve is shown above the cylinder and is of the slide valve type. It is operated by a shaft eccentric mounted on the crankshaft. In the model, the valve is made of wood and slides back and forth to admit steam to each side of the piston. The cut-off is the separate brass slide valve above the main valve. It is operated by its own eccentric, and the range of its travel is controlled by the brass hand crank and gears. Turning the crank thus allowed the point of steam cut-off to be varied as required.
label: Description
content: Allen’s design in this patent was soon improved by himself and others to allow for a simpler mechanism that did not require the separate slide valve for cut-off.
label: Description
content: The patent model is constructed of brass and wood. All of the key elements of the patent are illustrated by the model. It includes a small hand crank to permit demonstration of actual operation. A full description of the operation of the valve gear along with complete diagrams 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: New York
label: associated place
content: United States: New York, New York City
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.308649
label: catalog number
content: 308649
label: accession number
content: 89797
label: patent number
content: 2,227
objectType: label: Object Name
content: engine, steam, cut off valve
label: Object Name
content: engine, steam, cut off valve, model
label: Object Name
content: patent model, valve, steam engine cut off
physicalDescription: label: Measurements
content: on block: 8 in x 32 in; 20.32 cm x 81.28 cm