Allen Cut-Off Valve Gear, Patent Model
date: label: date made
content: 1848
label: patent date
content: 1848-08-29
name: label: maker
content: Allen, Horatio
notes: label: Description
content: This model was submitted to the U.S. Patent Office with the application for the patent issued to Horatio Allen, of New York, New York, August 29, 1848, no. 5745.
label: Description
content: This is an adjustable drop cut-off valve gear in which a poppet valve is raised by a lift rod but is permitted to return to its seat sooner or more rapidly than the lift rod returns.
label: Description
content: The model represents a poppet steam valve raised from its seat by an arm fixed at right angles to a lift rod, which works vertically and parallel to the valve stem. Upon the face of the arm is a moveable block a part of the upper surface of which is parallel to the face of the arm and a part of which is a steep curve. All the movement of the valve is transmitted to it through a roller on its stem, which rolls on the surface of this block. The block is so linked with a vibratory rod, which receives its motion from the cross head of the engine, that the block will move along the face of the lift rod arm and bring different points of its surface under the roller of the valve stem. By proper adjustment the roller will rest upon the flat part of the block and move with the lift rod as it is rising and the valve is opening, then the block moves so that the roller comes to the edge of the inclined portion and rolls down the incline permitting the valve to drop more quickly than the lift rod. The movement of the block on the arm and consequently the point of cut-off are fully adjustable.
label: Description
content: Reference:
label: Description
content: This description comes from the 1939 Catalog of the Mechanical Collections of the Division of Engineering United States Museum Bulletin 173 by Frank A. Taylor.
label: Location
content: Currently not on view
place: label: place made
content: United States: New York
setName: label: See more items in
content: Work and Industry: Mechanical and Civil Engineering
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content: Bulletin 173
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content: Engineering, Building, and Architecture
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content: Work
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content: Industry & Manufacturing
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.308643
label: catalog number
content: 308643
label: accession number
content: 89797
label: patent number
content: 5,745
objectType: label: Object Name
content: valve gear, steam engine
label: Object Name
content: valve gear, steam engine, model
label: Object Type
content: Patent Model
physicalDescription: label: Physical Description
content: wood (overall material)
label: Measurements
content: on walnut board - from catalog card: 16 in x 16 in; 40.64 cm x 40.64 cm
label: Measurements
content: overall: 16 in x 15 5/8 in x 2 1/2 in; 40.64 cm x 39.6875 cm x 6.35 cm