Bodemer’s Patent Model of an Indirect-Acting Governor – 1876

Bodemer’s Patent Model of an Indirect-Acting Governor – 1876

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This model was filed with the application to the U.S. Patent Office for Patent Number 176,591 issued to Johann Georg Bodemer of Zschopau, Saxony, Germany on April 25, 1876. The patent was for a speed governor capable of reducing to a minimum variations in the speed of a hydraulic turbine. The patent model as seen in the image is an exquisitely detailed example of the model-maker’s art. The design itself represents great mechanical ingenuity, perhaps at the expense of practicality of use.
The patent design was based on a loaded fly ball which can be seen at the top of the image of the model. Loaded fly ball type sensors had the advantage of quickly responding to small changes in speed. The patent claimed innovation was a regulator mechanism that would be disengaged while the speed was at the desired point. The regulator would be put into action immediately upon the loaded fly balls sensing small speed deviations and would remain in action until the governor sensed speed returning to normal. At that time, the regulator would again be disengaged and stay disengaged, assuming the machine would reach steady state at the desired speed. If it did not, the regulator would again be engaged in the proper direction to make additional corrections.
A governor of the Bodemer design was shown at the Centennial Exhibition at Philadelphia in 1876. A Simplified version was used to regulate the turbines of the inventor’s own plant.
The patent model is constructed of brass, steel and wood. A small brass plate on the base is marked “Modell von Bock & Handrick Dressden 550.”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 governor 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
governor, indirect acting, model
patent model, governor, indirect-acting
date made
patent date
Bodemer, Johann G.
place made
associated place
Germany: Saxony, Zschopau
overall: 12 in x 11 in x 6 in; 30.48 cm x 27.94 cm x 15.24 cm
ID Number
catalog number
accession number
patent number
Patent Models
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Work and Industry: Mechanical and Civil Engineering
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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