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.

Ashcroft Mfg. Co. of Bridgeport, Connecticut, manufactured this Tabor steam engine indicator, serial number 2325.
Description
Ashcroft Mfg. Co. of Bridgeport, Connecticut, manufactured this Tabor steam engine indicator, serial number 2325. It consists of a brass piston with three grooves; a vented brass cylinder; an internal, single wound spring, which can be changed; a large drum with a coil spring and a single record. The end of the linkage that holds the stylus is missing, as is the pulley. Accompanying the indicator is a box with several springs.
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.
A mechanical indicator consists of a piston, spring, stylus, and recording system. The gas pressure of the cylinder deflects the piston and pushes against the spring, creating a linear relationship between the gas pressure and the deflection of the piston against the spring. The deflection is recorded by the stylus on a rotating drum that is connected to the piston. Most indicators incorporate a mechanical linkage to amplify the movement of the piston to increase the scale of the record.
When the ratio of the frequency of the pressure variation to the natural frequency of the system is small, then the dynamic deflection is equal to the static deflection. To design a system with a high natural frequency, the mass of the piston, spring, stylus, and mechanical linkage must be small, but the stiffness of the spring must be high. The indicator is subjected to high temperatures and pressures and rapid oscillations, imposing a limitation on the reduction in mass. Too stiff a spring will result in a small displacement of the indicator piston and a record too small to measure with accuracy. Multiplication of the displacement will introduce mechanical ad dynamic errors.
The parameters of the problem for designing an accurate and trouble free recorder are such that there is no easy or simple solution. Studying the variety of indicators in the collection shows how different inventors made different compromises in their designs.
Location
Currently not on view
maker
Ashcroft Mfg. Co.
ID Number
MC.316791
catalog number
316791
accession number
228496
Ashcroft Mfg. Co. of Bridgeport, Connecticut, manufactured this Tabor steam engine indicator, serial number 7171.
Description
Ashcroft Mfg. Co. of Bridgeport, Connecticut, manufactured this Tabor steam engine indicator, serial number 7171. It consists of a brass piston with three grooves; a vented brass cylinder; an external, single wound spring, which can be changed; a large drum with a coil spring and a single record. The small knob to adjust the stylus pressure is missing. Accompanying the indicator is a box with several springs and reduction gear.
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.
A mechanical indicator consists of a piston, spring, stylus, and recording system. The gas pressure of the cylinder deflects the piston and pushes against the spring, creating a linear relationship between the gas pressure and the deflection of the piston against the spring. The deflection is recorded by the stylus on a rotating drum that is connected to the piston. Most indicators incorporate a mechanical linkage to amplify the movement of the piston to increase the scale of the record.
When the ratio of the frequency of the pressure variation to the natural frequency of the system is small, then the dynamic deflection is equal to the static deflection. To design a system with a high natural frequency, the mass of the piston, spring, stylus, and mechanical linkage must be small, but the stiffness of the spring must be high. The indicator is subjected to high temperatures and pressures and rapid oscillations, imposing a limitation on the reduction in mass. Too stiff a spring will result in a small displacement of the indicator piston and a record too small to measure with accuracy. Multiplication of the displacement will introduce mechanical ad dynamic errors.
The parameters of the problem for designing an accurate and trouble free recorder are such that there is no easy or simple solution. Studying the variety of indicators in the collection shows how different inventors made different compromises in their designs.
Location
Currently not on view
maker
Ashcroft Mfg. Co.
ID Number
MC.316792
catalog number
316792
accession number
228496
Ashcroft Mfg. Co. of Bridgeport, Connecticut, manufactured this Tabor steam engine indicator, serial number 2418.
Description
Ashcroft Mfg. Co. of Bridgeport, Connecticut, manufactured this Tabor steam engine indicator, serial number 2418. It consists of a steel piston with three grooves and a guide below the spring; a vented brass cylinder; an internal, single wound spring, which can be changed; a large drum with a coil spring and a single record. There is a Houghtaling worm gear reduction apparatus and a conical brass stylus. The piston, spring, and parts of the linkage are missing. Accompanying the indicator is a box with extra springs, piston, and worm reduction gear.
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.
A mechanical indicator consists of a piston, spring, stylus, and recording system. The gas pressure of the cylinder deflects the piston and pushes against the spring, creating a linear relationship between the gas pressure and the deflection of the piston against the spring. The deflection is recorded by the stylus on a rotating drum that is connected to the piston. Most indicators incorporate a mechanical linkage to amplify the movement of the piston to increase the scale of the record.
When the ratio of the frequency of the pressure variation to the natural frequency of the system is small, then the dynamic deflection is equal to the static deflection. To design a system with a high natural frequency, the mass of the piston, spring, stylus, and mechanical linkage must be small, but the stiffness of the spring must be high. The indicator is subjected to high temperatures and pressures and rapid oscillations, imposing a limitation on the reduction in mass. Too stiff a spring will result in a small displacement of the indicator piston and a record too small to measure with accuracy. Multiplication of the displacement will introduce mechanical ad dynamic errors.
The parameters of the problem for designing an accurate and trouble free recorder are such that there is no easy or simple solution. Studying the variety of indicators in the collection shows how different inventors made different compromises in their designs.
Location
Currently not on view
maker
Ashcroft Mfg. Co.
ID Number
MC.316790
catalog number
316790
accession number
228496
Ashcroft Mfg. Co. of Bridgeport, Connecticut, manufactured this Tabor steam engine indicator, serial number 2839.
Description
Ashcroft Mfg. Co. of Bridgeport, Connecticut, manufactured this Tabor steam engine indicator, serial number 2839. It consists of a brass piston with four grooves; a brass cylinder with an adjustable sleeve with vents; an internal, single wound spring, which can be changed; a large drum with a coil spring and a single record. It has a short pencil lead at the end for a stylus. Accompanying the indicator is a box with three springs, two turn cocks, an extra drum spring, pencil points, wrench, pad of record paper, a special board for record, and three scales.
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.
A mechanical indicator consists of a piston, spring, stylus, and recording system. The gas pressure of the cylinder deflects the piston and pushes against the spring, creating a linear relationship between the gas pressure and the deflection of the piston against the spring. The deflection is recorded by the stylus on a rotating drum that is connected to the piston. Most indicators incorporate a mechanical linkage to amplify the movement of the piston to increase the scale of the record.
When the ratio of the frequency of the pressure variation to the natural frequency of the system is small, then the dynamic deflection is equal to the static deflection. To design a system with a high natural frequency, the mass of the piston, spring, stylus, and mechanical linkage must be small, but the stiffness of the spring must be high. The indicator is subjected to high temperatures and pressures and rapid oscillations, imposing a limitation on the reduction in mass. Too stiff a spring will result in a small displacement of the indicator piston and a record too small to measure with accuracy. Multiplication of the displacement will introduce mechanical ad dynamic errors.
The parameters of the problem for designing an accurate and trouble free recorder are such that there is no easy or simple solution. Studying the variety of indicators in the collection shows how different inventors made different compromises in their designs.
Location
Currently not on view
maker
Ashcroft Mfg. Co.
ID Number
1981.0217.21
accession number
1981.0217
catalog number
1981.0217.21
Ashcroft Mfg. Co. of Bridgeport, Connecticut, manufactured this Tabor steam engine indicator, serial number 2329.
Description
Ashcroft Mfg. Co. of Bridgeport, Connecticut, manufactured this Tabor steam engine indicator, serial number 2329. It consists of a steel piston with a guide below the spring; a vented brass cylinder; an internal, single wound spring, which can be changed; a large drum with a coil spring and a single record. The piston, spring, and parts of the linkage are missing.
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.
A mechanical indicator consists of a piston, spring, stylus, and recording system. The gas pressure of the cylinder deflects the piston and pushes against the spring, creating a linear relationship between the gas pressure and the deflection of the piston against the spring. The deflection is recorded by the stylus on a rotating drum that is connected to the piston. Most indicators incorporate a mechanical linkage to amplify the movement of the piston to increase the scale of the record.
When the ratio of the frequency of the pressure variation to the natural frequency of the system is small, then the dynamic deflection is equal to the static deflection. To design a system with a high natural frequency, the mass of the piston, spring, stylus, and mechanical linkage must be small, but the stiffness of the spring must be high. The indicator is subjected to high temperatures and pressures and rapid oscillations, imposing a limitation on the reduction in mass. Too stiff a spring will result in a small displacement of the indicator piston and a record too small to measure with accuracy. Multiplication of the displacement will introduce mechanical ad dynamic errors.
The parameters of the problem for designing an accurate and trouble free recorder are such that there is no easy or simple solution. Studying the variety of indicators in the collection shows how different inventors made different compromises in their designs.
Location
Currently not on view
maker
Ashcroft Mfg. Co.
ID Number
MC.316794
catalog number
316794
accession number
228496
Ashcroft Mfg. Co. of Bridgeport, Connecticut, manufactured this Tabor steam engine indicator, serial number 1624.
Description
Ashcroft Mfg. Co. of Bridgeport, Connecticut, manufactured this Tabor steam engine indicator, serial number 1624. It consists of a steel piston with a spherical guide below the spring; a vented brass cylinder; an internal, single wound spring, which can be changed; a large drum with a coil spring and a single record; and a conical brass stylus. The spring is missing.
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.
A mechanical indicator consists of a piston, spring, stylus, and recording system. The gas pressure of the cylinder deflects the piston and pushes against the spring, creating a linear relationship between the gas pressure and the deflection of the piston against the spring. The deflection is recorded by the stylus on a rotating drum that is connected to the piston. Most indicators incorporate a mechanical linkage to amplify the movement of the piston to increase the scale of the record.
When the ratio of the frequency of the pressure variation to the natural frequency of the system is small, then the dynamic deflection is equal to the static deflection. To design a system with a high natural frequency, the mass of the piston, spring, stylus, and mechanical linkage must be small, but the stiffness of the spring must be high. The indicator is subjected to high temperatures and pressures and rapid oscillations, imposing a limitation on the reduction in mass. Too stiff a spring will result in a small displacement of the indicator piston and a record too small to measure with accuracy. Multiplication of the displacement will introduce mechanical ad dynamic errors.
The parameters of the problem for designing an accurate and trouble free recorder are such that there is no easy or simple solution. Studying the variety of indicators in the collection shows how different inventors made different compromises in their designs.
Location
Currently not on view
date made
ca 1878
maker
Ashcroft Mfg. Co.
ID Number
MC.319485
catalog number
319485
accession number
237917

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