Babcock and Wilcox Valve Gear, Patent Model
date: label: date made
content: 1866
label: patent date
content: 1866-04-24
name: label: inventor
content: Babcock, George H.
label: inventor
content: Wilcox, Jr., Stephen
notes: label: Description
content: This model was submitted to the U.S. Patent Office with the application for the patent issued to G. H. Babcock and S. Wilcox, Jr., of Providence, Rhode Island, April 24, 1866, no. 54090.
label: Description
content: The valve gear represented by the model is an early governable one of the class of riding cut-off valves in which the riding valve is operated by a small independent auxiliary steam cylinder, equipped with its own steam valve. The valve controlling the admission of steam to the auxiliary steam cylinder is in turn controlled by the action of the engine governor.
label: Description
content: The main valve of the engine is a flat lap valve, machined top and bottom with mortises through the valve near each end. The valve functions as a common D-valve admitting steam through the mortises instead of at its ends. Solid cut-off valves working on the back of the main valve, over the mortises, are joined by a rod, which passes through a small auxiliary steam cylinder and at the middle of which within the cylinder is the small actuating piston. The valve of the auxiliary cylinder is operated transversely across the cylinder by an eccentric on the end of a lay shaft. This shaft revolves at the same speed as the crankshaft and the main-valve eccentric, but its position at any time relative to the main-valve eccentric is determined by the governor as follows:
label: Description
content: The lay shaft is divided into two shafts, one driving, the other driven. The connection between the two is maintained by means of a driving bevel gear on the driving shaft, an intermediate idling bevel gear, and a driven bevel gear on the driven shaft. Though the driving and driven shafts turn in opposite directions, they turn with the same relative positions so long as the intermediate gear remains in one position. However, the axle of the intermediate fear is pivoted about the driving shaft and is held in position only by the governor rod, and the position of the intermediate gear changes with each change of position of the governor rod. A change in position of the intermediate gear advances or sets back the position of the driven shaft relative to the driving shaft and varies the action of the auxiliary steam valve relative to the action of the main-valve eccentric.
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 Jersey
label: associated place
content: United States: Rhode Island, Providence
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.308673
label: catalog number
content: 308673
label: accession number
content: 89797
label: patent number
content: 54,090
objectType: label: Object Name
content: valve, cut-off, model
label: Object Name
content: patent model, valve, cut off
label: Object Type
content: Patent Model
physicalDescription: label: Physical Description
content: wood (overall material)
label: Measurements
content: cylinder-from catalog card: 4 in x 12 in; 10.16 cm x 30.48 cm
label: Measurements
content: overall: 4 1/4 in x 3 1/4 in x 11 1/8 in; 10.795 cm x 8.255 cm x 28.2575 cm