This model was filed with the application to the U.S. Patent Office for Patent Number 29,642 issued to G.W. Van Deren of Bigflats, New York on August 14, 1860. The patent was for a steam engine design employing an oscillating piston. Instead of the more common straight cylinder with a piston within, Van Deren employed two pistons within a semi-circular cylinder. The pistons were connected by a curved rod with a pin in the middle for attachment of the connecting rod to the crankshaft. A steam valve above the cylinder admitted and exhausted steam alternatively for one, then the other piston. This caused a rocking motion of the pistons, and the connecting rod imparted rotation to the flywheel via the crank arm. This eliminated the need for crossheads and slides.
The inventor claimed that his design reduced stresses on the engine at the end of each cycle of the pistons and thus allowed operation at higher speeds. He also claimed reduced costs of construction. A search of available material did not reveal any commercial use of Van Deren’s design. He held two additional patents for components of oscillating steam engines.
The patent model is constructed of iron and steel. All of the key elements of the patent are illustrated by the model which demonstrates the engine motion. In the image the steam valve housing is the horizontal cylinder at the top of the model. The inlet is the orange pipe and the exhaust is from the top of the valve housing. The engine’s cylinder containing the pistons is the green semi-circular structure below the steam valve housing. The horizontal steel rod in front is the connecting rod from the pistons to the crankshaft. The valve gear eccentric is shown on the crankshaft on the right with its connected rods and levers to operate the valve. Diagrams showing the complete design of the patent can be found in the patent document online at the United States Patent and Trademark Office website, www.uspto.gov.
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