Seller’s Patent Model of an Oscillating Steam Engine – ca 1872

Seller’s Patent Model of an Oscillating Steam Engine – ca 1872

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This model was filed with the application to the U.S. Patent Office for Patent Number 127,928 issued to William Sellers of Philadelphia, Pennsylvania on June 11, 1872. The patent was for improvements in oscillating steam engines. An oscillating steam engine differs from a standard engine in that the steam cylinder is pivoted on the engine frame and oscillates back and forth about the pivot as its connecting rod operates the crankshaft of the engine. In a standard engine, the cylinder is fixed in orientation, and the piston rod is connected to a crosshead which moves fore and aft within a set of guides. The crosshead in turn is coupled via a pin to the connecting rod which allows it to pivot independently as the crankshaft revolves. One advantage of the oscillating cylinder design is the engine occupies less space than a standard engine.
Other patents for oscillating engines with similar valve arrangements predated Mr. Sellers’ patent. He claimed the objectives of his invention were to improve the operation of the steam valve for an oscillating engine and to reduce the wear on the seals for the piston rod. In the image of the model the steam valve is the brass box on top of the cylinder. Mr. Sellers’ improvement in the valve design deals with the mechanism for controlling the timing of the steam cut-off in the valve. His improvement for the piston rod seal consists of a bearing placed in a sleeve which could be adjusted by a nut to compensate for wear of the rod. This can be seen in the rear center of the image.
Mr. Sellers was a prolific inventor, and his most notable work was in the area of standardized screw and bolt threads.
The patent model is made of brass and other metal and mounted on a wood base. It is highly detailed and illustrates all of the key details of the Sellers patent. The model was built as a working model to demonstrate the operation of the engine. A full description of the operation of the engine along with complete diagrams of the patent can be found in the patent document online at the United States Patent and Trademark Office website,
Object Name
engine, steam, oscillating, model
engine, steam, oscillating, patent model
patent model, engine, oscillating steam
date made
patent date
Sellers, William
place made
United States: Pennsylvania
associated place
United States: Pennsylvania, Philadelphia
Physical Description
brass (overall material)
wood (base material)
overall: 3 1/2 in x 4 3/4 in x 7 in; 8.89 cm x 12.065 cm x 17.78 cm
ID Number
catalog number
patent number
accession number
Patent Models
Steam Engines
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Work and Industry: Mechanical and Civil Engineering
Industry & Manufacturing
Patent Models
Engineering, Building, and Architecture
Power Machinery
Exhibition Location
National Museum of American History
Data Source
National Museum of American History
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