Engineering, Building, and Architecture

Not many museums collect houses. The National Museum of American History has four, as well as two outbuildings, 11 rooms, an elevator, many building components, and some architectural elements from the White House. Drafting manuals are supplemented by many prints of buildings and other architectural subjects. The breadth of the museum's collections adds some surprising objects to these holdings, such as fans, purses, handkerchiefs, T-shirts, and other objects bearing images of buildings.

The engineering artifacts document the history of civil and mechanical engineering in the United States. So far, the Museum has declined to collect dams, skyscrapers, and bridges, but these and other important engineering achievements are preserved through blueprints, drawings, models, photographs, sketches, paintings, technical reports, and field notes.

This model was filed with the application to the U.S. Patent Office for Patent Number 44,572 issued to S. Lloyd Wiegand of Philadelphia, Pennsylvania on October 4, 1864. Mr. Wiegand’s patent was for improvements in gas engines.
Description
This model was filed with the application to the U.S. Patent Office for Patent Number 44,572 issued to S. Lloyd Wiegand of Philadelphia, Pennsylvania on October 4, 1864. Mr. Wiegand’s patent was for improvements in gas engines. Claimed improvements included: protection against the buildup of carbon deposits on the piston and cylinder; more accurate and fuel-efficient speed control; and a lower cost and higher durability construction.
Mr. Wiegand’s engine was designed to use “illuminating gas” which was a coal based product used for gas lighting. Due to inefficiency in combining the gas and air, carbon deposits were left on the surfaces of the combustion chambers. This damaged the seals between the cylinders and pistons resulting in leakage and reduced power. The patent called for a fluid to be injected into the cylinders via channels near the seals. The fluid would loosen and eject the carbon through the exhaust.
To improve the speed regulation and fuel-efficiency of the engine, Mr. Wiegand varied the timing of the intake valves. A shaft governor was included in one of the engine’s two flywheels, and this was coupled to a mechanism that adjusted the angle of the cam which opened and closed the valve. If the engine exceeded its desired speed, the cam adjustment would shorten the time the intake valve was open. The reduction in the amount of fuel entering the engine soon slowed it.
A search of available literature did not reveal any practical use of the patent. Shortly after Mr. Wiegand’s patent, N. A. Otto and others patented advances in gas engine such as compressing the fuel-air mixture prior to combustion and the introduction of the four stroke engine design.
The model as shown in the image illustrates all of the key elements of the patent except for the internal details of the valves and cylinders. It is constructed of metal. Diagrams showing the complete design can be found in the patent document online (www.USPTO.gov).
Location
Currently not on view
date made
1864
patent date
1864-10-04
inventor
Weigand, S. Lloyd
maker
Wiegand, S. Lloyd
ID Number
ER.325619
accession number
249602
catalog number
325619
patent number
44,572
This diesel engine indicator was based on U.S. Patent Number 2,040,082 issued to Kalman John De Juhasz of State College, Pennsylvania on May 12, 1936.
Description
This diesel engine indicator was based on U.S. Patent Number 2,040,082 issued to Kalman John De Juhasz of State College, Pennsylvania on May 12, 1936. An engine indicator is an instrument for graphically recording the pressure versus piston displacement through an engine stroke cycle. Engineers use the resulting diagram to check the design and performance of the engine. Engine indicators were originally developed for use on steam engines, and Mr. De Juhasz's design is one of many adaptations of steam engine indicator designs for use on diesel engines.
The device consists of a piston within a cylinder as shown on the right in the image. This cylinder is connected to a port in a cylinder of the engine under test, and the indicator's piston rises and falls as the pressure within the engine changes. A spring at the top of the cylinder provides a return force when the pressure in the engine decreases. A stylus is connected via a linkage to the moving piston so that it also rises and falls with pressure changes and records the pressure on a revolving drum with a paper card wrapped around it. This drum is seen to the left of the image. A cord is wrapped around the base of the drum and led via the pulley on the left to be attached to the engine under test so that it causes the drum to turn one revolution each stroke of the engine. A spring on the inside of the drum returns the recording paper to its starting point as the cord is relaxed. The result is a pressure-volume diagram of the engine while in operation, and engineers can measure and adjust the engine's properties under real time varying load conditions.
De Juhasz claimed his design improved over others due to his addition of cooling fins to the piston cylinder, reduction of mass of the piston and stylus, the use of light weight materials such as Bakelite, and a built in lubricator. He was an Assistant Professor of Engineering at Pennsylvania State College and Chief Engineer of a company manufacturing engine indicators.
The indicator is constructed of steel and Bakelite. Diagrams showing the complete design of the patent that it is based upon can be found in the patent document online at the United States Patent and Trademark Office website, www.uspto.gov.
date made
ca 1938
ID Number
MC.311621
catalog number
311621
accession number
151188
patent number
2040082

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