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Found 344 Resources

Maihak Steam Engine Indicator

National Museum of American History
This case contains two steam engine indicators, serial numbers 3027 and 3028, manufactured by H. Maihak of Hamburg, Germany. It consists of a steel piston with three grooves; a steel cylinder; an external spring, which is missing on both indicators; a large drum with a spiral spring and continuous record; and a brass stylus. The record paper is inside the drum and uses a ratchet and pawl to turn and retrieve it.

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.

Robertson-Thompson Steam Engine Indicator

National Museum of American History
This Robertson-Thompson steam engine indicator, serial number 7735, consists of a brass piston with two grooves; a brass cylinder; an internal, single wound spring, which can be changed; a medium sized drum with a coil spring and a single record; and a short pencil lead for the stylus. Accompanying the indicator is a box with two extra springs, drum springs, seven wooden pulleys for the reducer, two scales, and two extra pistons.

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.

Richards-Elliott Steam Engine Indicator

National Museum of American History
The Elliot Bros. of London manufactured this steam engine indicator. It consists of a brass piston with single groove; a vented brass cylinder; an internal, single wound spring, which can be changed; a large, brass drum that is nickel plated with a coil spring and single record; and a heavy, steel stylus.

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.

Batchelder-Bushnell Steam Engine Indicator

National Museum of American History
Batchelder and Bushnell manufactured this steam engine indicator. It consists of a brass piston and cylinder. It has a cantilever spring enclosed in a tube, with the stiffness changed by length adjustment and a scale on the side of the tube. It has a large drum with coil spring and single record. It has a large brass stylus.

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.

Thompson Steam Engine Indicator

National Museum of American History
The American Steam Gauge Co. of Boston, Massachusetts, manufactured this steam engine indicator, serial number 1875. J.W. Thompson patented this style of indicator on August 31, 1875, patent number 167,364.

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.

Steam Engine Indicator

National Museum of American History
The American Steam Gauge Co. of Boston, Massachusetts, manufactured this steam engine indicator, serial number 6216. It consists of a brass piston; a vented brass cylinder; an external spring, which is missing; a large drum with a coil spring and single record; and brass stylus.

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.

Stein Steam Engine Indicator

National Museum of American History
This steam engine indicator, serial number 24296, was manufactured by Stein Sohn of Hamburg, Germany. It consists of a brass piston with two grooves; a vented brass cylinder; an internal, double wound spring, which can be changed; and a brass holder for a pencil. The large drum is damaged and cannot be taken apart for inspection, but it probably contains a spiral spring. Accompanying the indicator is a box with two springs, a scale reduction parallelogram, a tri-square pulley and bracket, and a knob to adjust the pencil pressure on the drum.

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.

De Juhasz Gas Engine Indicator

National Museum of American History
This gas engine indicator, manufactured by Kalman J. De Juhasz, is very similar to another one in the collection (catalog number 311.621). It is a modification of the steam engine indicator to adapt it for use on diesel engines. The improvements consist of cooling fins, reduced masses of piston and pencil movement, light Bakelite drum, ball bearings for drum and roller, and a built-in indicator.

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.

Lehmann & Michels Gas Engine Indicator

National Museum of American History
Lehmann & Michels manufactured this gas engine indicator, serial number D. R. P. 416623. It is based on patent number 1532692, which was granted to Josef Geiger of Augsburg, Germany, on April 7, 1925.

The L & M catalog describes this instrument as a Pi-Meter and instrument to measure the mean pressure. There is no record, pointer, or dial. Most likely, it contains a heavy fly wheel that is damped, an impulse of gas pressure each cycle does work on fly wheel, and the work determines the velocity which is transcribed into a mean pressure for each stroke of the piston.

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.

Elliot Bros. Steam Engine Indicator

National Museum of American History
The Elliot Bros. of London manufactured this steam engine indicator. It consists of a small diameter brass piston; a vented brass cylinder; an internal, single wound spring, which can be changed; a small drum with a coil spring; a roll of paper inside the drum, which is hand fed; and a heavy brass slide and stylus.

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.

Tabor Steam Engine Indicator

National Museum of American History
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.

Tabor-Ashcroft Steam Engine Indicator

National Museum of American History
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.

Steam Engine Indicator

National Museum of American History
This steam engine indicator consists of a steel piston with three grooves, which can be changed; a vented steel cylinder; an external, double wound spring, which can be changed; and a brass stylus. The drum assembly is missing. Accompanying the indicator is a box with two extra pistons and liners, seven extra springs, and one turn cock.

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.

Star Steam Engine Indicator

National Museum of American History
The Star Brass Mfg. Co. manufactured this steam engine indicator, serial number 485. It consists of a steel piston; a steel cylinder; an external spring, which is missing; a small drum with a spiral spring and a single record. The stylus is missing, but is likely a pencil point. The accompanying box has five double wound 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.

Thompson-American Steam Gauge Steam Engine Indicator

National Museum of American History
The American Steam Gauge Co. of Boston, Massachusetts, manufactured this steam engine indicator, serial number 662. It consists of a brass piston; a vented brass cylinder; an internal, single wound spring, which can be changed; a large drum with a coil spring and single record; and brass stylus.

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.

Benson’s Patent Model of a Steam Engine and Pump – ca 1847

National Museum of American History
This model was filed with the application to the U.S. Patent Office for Patent Number 5,185 issued to Benjamin S. Benson of Baltimore, Maryland on July 10, 1847. The patent was for an improved design for steam engines and pumps. It was a very early example of a “wobble disk” type of design, which has been used in many engine and pump designs.

As seen in the image of the model, the engine consists of four single-acting cylinders placed around the axis of the shaft shown in the front right. A second shaft at the front left is connected to the piston rods of the cylinders via a crank arm and ball and socket joints. Ports located in the faceplate holding the cylinders admit and exhaust steam to each cylinder in turn as it rotates around the shaft axis. The angle between the two shafts causes the pistons’ lateral forces to be converted to rotational force as each piston is pushed out by the steam and then pulled back in due to atmospheric pressure.

The third shaft seen at the rear of the model is coupled via bezel gears to the other two shafts and is used as the output shaft of the engine. Benson noted this was desirable to reduce stress on the piston rods and connecting arms. He noted that essentially the same mechanism could be used to pump fluids by applying external power to this shaft. The fluid would be pumped through the same valve mechanism as used for the engine.

The patent model is constructed primarily of brass and steel and illustrates the important elements of Benson’s design. 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, /www.uspto.gov.

Higginson’s Patent Model of a Radial Steam Engine - 1877

National Museum of American History
This model was filed with the application to the U.S. Patent Office for Patent Number 196,451 issued to Andrew Higginson of Liverpool, England on October 23, 1877. The patent was for an improved design for reciprocating steam engines. His patent application described three designs. One was for a single rectangular piston, non-reversing engine. The second was for a three piston version that was non-reversing. The third design, and the one represented by this model, was for a three piston engine that could be reversed. The control lever seen at the right of the image of the model was for controlling the direction of rotation.

Higginson provided two ports in the walls of each of the steam “cylinders.” As a piston oscillated up and down, a port in the skirt of the piston alternately exposed each of the ports in the wall. The control lever determined which port received steam and which acted as the exhaust and, thus, the direction of rotation. He claimed that the use of rectangular “cylinders” made the engine easier to construct and to obtain tight seals with the pistons.

The patent model is constructed of brass and illustrates of the important elements of Higginson’s design. Although not visible in the image, the rear of the model has cut-away sections to reveal parts of the pistons and valve ports. 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, /www.uspto.gov.

Star Steam Engine Indicator

National Museum of American History
The Star Brass Mfg. Co. manufactured this steam engine indicator, serial number 760. It consists of a steel piston with one groove; a vented brass cylinder; an external, double wound spring, which can be changed; a small drum with a spiral spring and a single record. The stylus 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.

Schaeffer & Budenberg Steam Engine Indicator

National Museum of American History
Schaeffer and Budenberg manufactured this steam engine indicator, serial number 11059. It consists of a large steel piston with two grooves; a brass cylinder and aluminum body; an internal spring, which is missing; a light aluminum drum with a spiral spring and a single record; and a brass stylus.

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.

Do Our Brains Find Certain Shapes More Attractive Than Others?

Smithsonian Magazine

Jean (Hans) Arp, Consiente de sa Beauté (Conscious of Her Beauty), 1957, polished bronze. Image courtesy of Chrystal Smith, Art Associate, Science.

A century ago, a British art critic by the name of Clive Bell attempted to explain what makes art, well, art. He postulated that there is a “significant form”—a distinct set of lines, colors, textures and shapes—that qualifies a given work as art. These aesthetic qualities trigger a pleasing response in the viewer. And, that response, he argued, is universal, no matter where or when that viewer lives.

In 2010, neuroscientists at the Zanvyl Krieger Mind/Brain Institute at Johns Hopkins University joined forces with the Walters Art Museum in Baltimore to conduct an experiment. What shapes are most pleasing, the group wondered, and what exactly is happening in our brains when we look at them? They had three hypotheses. It is possible, they thought, that the shapes we most prefer are more visually exciting, meaning that they spark intense brain activity. At the same time, it could be that our favorite shapes are serene and calm brain activity. Or, they surmised we very well might gravitate to shapes that spur a pattern of alternating strong and weak activity.

Image courtesy of Zanvyl Krieger Mind/Brain Institute, Johns Hopkins University

To investigate, the scientists created ten sets of images, which they hung on a wall at the Walters Art Museum in 2010. Each set included 25 shapes, all variations on a laser scan of a sculpture by artist Jean Arp. Arp’s work was chosen, in this case, because his sculptures are abstract forms that are not meant to represent any recognizable objects. Upon entering the exhibition, called “Beauty and the Brain,” visitors put on a pair of 3D glasses and then, for each image set, noted the their “most preferred” and “least preferred” shape on a ballot. The shapes were basically blobs with various appendages. The neuroscientists then reviewed the museum-goers’ responses in conjunction with fMRI scans taken on lab study participants looking at the very same images.

Image courtesy of Zanvyl Krieger Mind/Brain Institute, Johns Hopkins University

“We wanted to be rigorous about it, quantitative, that is, try to really understand what kind of information neurons are encoding and…why some things would seem more pleasing or preferable to human observers than other things. I have found it to be almost universally true in data and also in audiences that the vast majority have a specific set of preferences,” says Charles E. Connor, director of the Zanvyl Krieger Mind/Brain Institute.

Beauty and the Brain Revealed,” an exhibition now on display at the AAAS Art Gallery in Washington, D.C., allows others to participate in the exercise, while also reporting the original experiment’s results. Ultimately, the scientists found that visitors like shapes with gentle curves as opposed to sharp points. And, the magnetic brain imaging scans of the lab participants prove the team’s first hypothesis to be true: these preferred shapes produce stronger responses and increased activity in the brain.

As Johns Hopkins Magazine so eloquently put it, “Beauty is in the brain of the beholder.”

Now, you might expect, as the neuroscientists did, that sharp objects incite more of a reaction, given that they can signal danger. But the exhibition offers up some pretty sound reasoning for why the opposite may be true.

“One could speculate that the way we perceive sculpture relates to how the human brain is adapted for optimal information processing in the natural world,” reads the display. “Shallow convex surface curvature is characteristic of living organisms, because it is naturally produced by the fluid pressure of healthy tissue (e.g. muscle) against outer membranes (e.g. skin). The brain may have evolved to process information about such smoothly rounded shapes in order to guide survival behaviors like eating, mating and predator evasion. In contrast, the brain may devote less processing to high curvature, jagged forms, which tend to be inorganic (e.g. rocks) and thus less important.”

Image courtesy of Flickr user wecand

Another group of neuroscientists, this time at the University of Toronto at Scarborough, actually found similar results when looking at people’s preferences in architecture. In a study published in the Proceedings of the National Academy of Sciences earlier this year, they reported that test subjects shown 200 images—of rooms with round columns and oval ottomans and others with boxy couches and coffee tables—were much more likely to call the former “beautiful” than the latter. Brain scans taken while these participants were evaluating the interior designs showed that rounded decor prompted significantly more brain activity, much like what the Johns Hopkins group discovered.

“It’s worth noting this isn’t a men-love-curves thing: twice as many women as men took part in the study. Roundness seems to be a universal human pleasure,” writes Eric Jaffe on Co.Design.

Gary Vikan, former director of the Walters Art Museum and guest curator of the AAAS show, finds “Beauty and the Brain Revealed” to support Clive Bell’s postulation on significant form as a universal basis for art, as well as the idea professed by some in the field of neuroaesthetics that artists have an intuitive sense for neuroscience. Maybe, he claims, the best artists are those that tap into shapes that stimulate the viewer’s brain.

“Beauty and the Brain Revealed” is on display at the AAAS Art Gallery in Washington, D.C., through January 3, 2014.

Pease’s Patent Model of an Oil Ejector Pump – ca 1865

National Museum of American History
.This model was filed with the application to the U.S. Patent Office for Patent Number 47,034 issued to Francis S. Pease of Buffalo, New York on March 28, 1865. The patent was for a pump design for raising oil and other liquids from deep wells.

The concept was to apply to the well alternating pulses first of high pressure air and then a vacuum in order to progressively draw liquid from the bottom. His design called for a steam-driven air pump to be connected to two cylinders. One cylinder was connected to the intake of the air pump, and the other was connected to the exhaust. In operation one cylinder developed a vacuum while the other became pressurized.

As seen in the image of the patent model, the horizontal air pump is at the bottom, and the two vertical cylinders are mounted on either side of a vertical shaft with a lever arm at the top. The patent refers to this lever arm as the “vibrating lever”, and in an actual pump it would be driven by the steam engine. Its purpose was to alternately open and close a series of valves in the two cylinders thereby creating either a vacuum or high pressure in the horizontal pipe (shown just beneath the lever arm) which ran down to the lower portion of the well pipe.

As the pump was put in operation to send pressurized air down the air tube, the pressure increase at the bottom of the well forced air and any liquid that was present upwards. Stopper valves prevented backflow while the next cycle’s vacuum drew the liquid up further. Repeated and rapid operation of the lever could therefore raise the liquid to the top of the well.

Mr. Pease claimed that his invention would result in much more rapid and efficient pumping of large volumes of liquid. He compared his design to the then current pump designs which had long wooden piston rods extending from the top of the well to a plunger valve at the bottom. Each stroke of a pump of such a design required the rod to be lifted and lowered. This required additional energy from the pumping power source and significantly slowed the stroke rate. He claimed his pump design could be much faster than the 40 to 60 strokes per minute of those pumps.

Mr. Pease was an oil dealer in the Buffalo, New York area and was the holder of a number of other patents dealing with the oil industry. A search of available trade literature material did not reveal any commercial use of the design of this patent.

The patent model is shown in the image. It is made of brass and wood and illustrates the main external elements of the pumping mechanism of Mr. Pease’s design. The various valves and tubes that would be located beneath the surface are not modelled. Diagrams showing the complete design can be found in the patent document online (/www.USPTO.gov).

Beginning the folk guitar [sound recording] : an instruction record for beginners / by Jerry Silverman

Ralph Rinzler Folklife Archives and Collections
Based on the book Beginning the folk guitar, by Jerry Silverman (Oak, 1964); the book is laid in the original container.

Three (3) instruction booklets are laid in original container: part 1 (8 p. : ill. + notation + tablature), part 2 (8 p. : ill. + notation), part 3 (8 p. : notation).

Cover design by Ronald Clyne. Cover photo by David Gahr.

Related materials may be found in the Moses and Frances Asch Collection, also held by this repository. Related materials may include correspondence pertaining to the recording, original cover art designs, production materials, business records, and audiotapes from studio production.

Vera’s Patent Model of a Friction Heater – ca 1869

National Museum of American History
This model was filed with the application to the U.S. Patent Office for Patent Number 86,046 issued to Pedro Vera of Bogota, United States of Colombia, on January 19, 1869. Mr. Vera’s patent was for improvements in machines designed to create heat by friction, for the purpose of generating steam or warming apartments. The main element of his design was a series of rotating disks in contact with stationary diaphragms. The friction between the disks and diaphragms produced heat which would be transferred to the water or air in contact with them. The alternating disks and diaphragms were mounted on shafts with the diaphragms being held stationary by four small rods along their diameters and running the length of the shafts. The rotating disks were keyed to the shafts. In the patent description, four shafts were mounted vertically inside a sealed cylinder that was intended to be water and steam-tight and strong enough to withstand the steam pressure of ordinary boilers. Springs were mounted between the tops of the shafts and the top of the cylinder in order to press the disk/diaphragm assemblies together to increase friction as desired. Each of the shafts exited the top of the cylinder via stuff-box seals and was topped with a pinion gear. The pinion gears were driven by a central gear on a shaft extending down through the cylinder. A pulley at the top of this shaft would be rotated via a belt by a source of power. The speed of the drive pulley would control the amount of heat generated by the device. Research of available trade literature and other sources has not revealed any commercial use that may have made use of Mr. Vera’s invention.

The patent model is constructed of brass. It illustrates the sealed case containing the disk mechanisms, the stuffing-box seals for the shafts to exit, and the pulley and gearing arrangement to drive the disks. An access door is provided on the model to allow visibility of the disks, diaphragms, supporting rods, and shafts. Diagrams showing the complete design can be found in the patent document online (/www.USPTO.gov/patents/process/search/index.jsp).

Gilman’s Patent Model of a Valve for an Oscillating Steam Engine – ca 1851

National Museum of American History
This model was filed with the application to the U.S. Patent Office for Patent Number 7,871 issued to Samuel H. Gilman of Cincinnati, Ohio on January 1, 1851. Mr. Gilman’s patent was for an improvement in the design of valve gear for an oscillating steam engine. An oscillating steam engine differs from a standard engine in that the steam cylinder is pivoted on the engine frame and oscillates up and down 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 moves fore and aft within a crosshead which allows the connecting rod to pivot independently as the crankshaft revolves.

Mr. Gilman did not claim as new an entire design of such an engine. He limited his claim to a modification of the tube that guides the pushrod which controls the steam valve. He included threads at the bottom of the rod and shaped that portion so that it could clamp and secure the ball at the end of the pushrod. When threaded into the collar on the valve housing it allowed the pushrod to move slightly to conform to the motion of the valve house. He referred to his improvement as a “tubular nut.” The patent did not elaborate on exactly what Mr. Gilman claimed for improved function.

The model as shown in the image illustrates all of the key elements of the patent. It is constructed of metal and mounted on a wooden base. Diagrams showing the complete design can be found in the patent document online (/www.USPTO.gov).
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