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Frank’s Patent Model of an Opposed Piston Steam Engine - 1875

National Museum of American History
This model was filed with the application to the U.S. Patent Office for Patent Number 169,249 issued to Samuel B. Frank of Marshall, Missouri on October 26, 1875. The patent was for an opposed piston steam engine with four pistons. The goal of the design was to reduce vibration caused by unbalanced reciprocating masses.

The four pistons were equally spaced within a single cylinder, and each cylinder traversed one fourth of the length of the cylinder. The two inner pistons were arranged to move towards each other while the outer pistons would move away from each other. The reverse order would take place on the next cycle. A single slide valve with multiple ports fed steam to the appropriate volumes between the pistons. Each piston had its own crosshead, two on the left of the engine and two on the right. Concentric piston rods were used to allow the rods for the outer pistons to pass inside those for the inner pistons.

The use of the two pairs of opposed pistons was claimed to reduce vibration, and Frank also claimed the engine would be more powerful than standard engines. As shown in the image the design was complex and had many moving parts and wearing surfaces. It is not known how practical the design was to manufacture and operate. A search of available literature did not produce any examples of actual use of the patent.

The patent model is made of brass and mounted on a wood base. It is highly detailed and illustrates all of the key details of the patent. 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.

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).

Ericsson’s Patent Model of a Marine Steam Engine – ca 1858

National Museum of American History
This model was filed with the application to the U.S. Patent Office for Patent Number 20,782 issued to John Ericsson of New York, New York on July 6, 1858. The patent was for improvements in marine steam engines for powering a screw propeller. Ericsson’s goal was to maximize the power and compactness of the engine so that it could be located transversely and very low within a boat.

His design consisted of two compact steam cylinders which were bolted together and mounted horizontally and across the beam of the ship. They drove a single propeller shaft via a system of push rods and rocker arms. The design allowed for even application of power with reduced vibration and wear on engine parts and the frame of the ship.

Ericsson was a prolific inventor; his inventions included many types of steam engines and associated apparatus as well as air engines. He designed the USS Monitor for the North during the Civil War. The engine for the Monitor was based on this patent.

The patent model is made of brass and is mounted on a wood base representing a section of the hull of a ship. A brass plate on the base of the model is engraved “Screw Propeller Engine, J. Ericsson, Inventor.” All of the key elements of the patent are illustrated by the model which was provided with a crank on the propeller shaft to allow operation for demonstration. A full description of the operation of the engine along with complete diagrams can be found in the patent document online at the United States Patent and Trademark Office website, /www.uspto.gov.

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).

patent model, vegetable assorter

National Museum of American History
This model was filed with the application to the U.S. Patent Office for Patent Number 212,000 issued to John H. Heinz of Sharpsburg, Pennsylvania, on February 4, 1879. Mr. Heinz’s patent was for a design to automate the sorting of vegetables (as well as fruits, pickles, etc.) by size. Commercial packing technology had improved significantly at the time of the patent, and to keep up with faster production timelines a more efficient sorting method not dependent on manual labor was needed. Mr. Heinz’s design is shown in the photo to the left. It consisted of a wooden frame that held two concentric cylinders mounted on a shaft that sloped downwards from right to left. The cylinders had longitudinal slots wide enough to allow items of that size to fall through. The machine would be operated by the crank shown at the left end. The crank turned the central shaft via a gear so that the cylinders revolved, distributing the items evenly within them. Near the left side of the photo the inner cylinder is visible where it exits from the larger, outer cylinder. A hopper, shown at the upper right of the machine, received the items to be sorted and introduced them into the inner cylinder. To reduce jamming and produce an even distribution of items, the hopper was vibrated by a ratchet and bar at the end of the shaft. The inner cylinder had slotted openings that were sized such that all but the largest items would fall through into the outer cylinder. The inner cylinder’s longitudinal slots ended where it exited from the outer cylinder because, at that point, only the largest items remained. They would travel down the closed inner cylinder to the collection bin at the left. The slots at the upper end of the outer cylinder were sized so that the smallest items to be sorted passed through and into a collection hopper shown at lower right. Medium sized items would travel down the outer cylinder to its left end where a plate would force them to fall into the middle collection hopper. Each collection hopper could be closed by slide-gates to hold the items until workers could empty them. While this patent model has provisions for just three grades of size, Mr. Heinz made note that his invention was not limited to any particular number. This patent improved upon an earlier one by Mr. Heinz which was Patent Number 197, 934, dated December 11, 1877. In a later patent (Number 212,849 dated March 4, 1879) Mr. Heinz and his brother and co-inventor, Henry J. Heinz (founder of the Heinz Company), provided further improvements in the sorter design. In that patent they limited their description to a design for sorting pickles. They did away with the concentric cylinders in favor of an inclined, vibrating box with exit slots of varying sizes to sort the pickles. In 1890 Mr. John H. Heinz again improved upon the designs with Patent Number 545,689, dated December 17, 1890. That design was for a more elaborate version of the concentric cylinder sorter.

The patent model is constructed of wood and metal. The model is complete and shows all the key elements of the patent with the exception of the collection hopper slide-gates which are missing. Diagrams showing the complete design can be found in the patent document online (/www.USPTO.gov/patents/process/search/index.jsp).

Howe’s Patent Model of a Pin Making Machine - ca 1841

National Museum of American History
This model was filed with the application to the U.S. Patent Office for Patent Number 2,013 issued to John Ireland Howe on March 24, 1841. Howe’s invention was a design for an automated common pin making machine. The goal of the design was to improve upon his earlier patented pin making machine which had not found commercial success. His design was mechanically very complex; the patent document comprised 20 pages of detailed text and five of diagrams. Howe had been a physician working in the New York Alms House where he had observed the inmates making pins by hand. He began to experiment with machinery for automating the process and sought the help of Robert Hoe, a printing press builder, to provide mechanical expertise. His design was for a machine that would take a roll of wire, cut the wire for each pin to proper length, sharpen and polish the pointed end of the pin, and finally form the other end into a metal head. The machine consisted of a series of individual chucks (devices much like on lathes) mounted radially on a vertical shaft that rotated inside a horizontal circular frame. Around the circumference of the frame were mounted various tools that shaped the pins. As the vertical shaft rotated, it brought the chucks into alignment with the tools. One type of tool was the point forming file, or mill. The chuck, which was rotating along the axis of the pin, would make the pin tip contact the file thus grinding it into shape. The file was also rotating as well as moving forward, backwards, and side-to-side in a complex manner so as to produce a point which was round, smooth, free from angles, and slightly convex in shape. Howe made provisions for multiple such tools to progressively shape the point. The other major tool was the head forming mechanism. A carrier removed the pin from its chuck and inserted its blunt end into a set of gripping jaws that held it into a set of dies. The dies formed a thickened section of metal at the end of the pin. A second carrier extracted the pin and inserted the thickened section into a second set of dies which then flattened and formed the final pin head. The machines made from the patent design enabled the Howe Manufacturing Company become one of the largest pin manufacturers in the United States.

The patent model is constructed primary of metal and is about one foot square and one foot tall. It represents the essential elements of the design such as the rotating set of chucks mounted on the vertical shaft, the sharpening mills, and the head making mechanisms. It shows how the rotating table brings the pins to the point sharpening mills. While it is uncertain that the model would be capable of actual pin production, it appears that turning the attached hand crank would cause the machine to go through the motions of actual pin production.

Ericsson’s Patent Model of a Cross-Compound Steam Engine – ca 1849

National Museum of American History
This modxel was filed with the application to the U.S. Patent Office for Patent Number 6,844 issued to John Ericsson of New York, New York on November 6, 1849. The patent was titled “Arrangement of Engine for Using Steam Expansively.” In a common engine design of the time, high pressure steam from a boiler was introduced to the engine’s cylinder for only a portion of the stroke. The steam “cut-off” valve was then closed, and the steam’s expansive force did the remainder of the work for that stroke. This saved fuel because of the reduced need for continuous high pressure steam.

The goal of Ericsson’s invention was to improve the ability of an engine to use the expansive force of steam for efficiency while still providing uniform power throughout the stroke of the engine. In his design the resistance applied to the piston rod by the load on the engine decreased in the exact ratio of the decreasing pressure of the steam as it expanded in the cylinder. He achieved this by using two cylinders of differing sizes and exhausting the steam from the smaller cylinder into the larger. At the same time, steam pressure was balanced on both sides of the piston of the smaller cylinder. The relative sizes of the cylinders were carefully chosen to equalize the force on the engine’s crankshaft. The patent application claimed that this equal force was maintained even with the steam expanded by a factor of over twenty. This was a significant improvement over existing designs.

Ericsson was a prolific inventor; his inventions included many types of steam engines and associated apparatus as well as air engines. He was the designer of the USS Monitor for the North during the Civil War and designed its engine as well as numerous other marine steam engines.

The patent model as shown in the image is constructed of wood. All of the key elements of the patent are illustrated by the model including the arrangement of the crankshafts and the steam valves and their operating mechanisms. 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.

Firmenich and Stiker’s Patent Model of a Steam Boiler - 1875

National Museum of American History
This model was filed with the application to the U.S. Patent Office for Patent Number 169,977 issued to Joseph Firmenich and Flavius P. Stiker of Buffalo, New York on November 16, 1875. The patent was for an improved design for steam boilers. The design was for a water tube type boiler in which water enclosed in a large number of pipes was exposed to the heat of the furnace. This was considered to offer safety advantages over the fire-tube type in which a large volume of water was pierced by tubes carrying hot flue gases.

Their design is shown in the image of the patent model. A brickwork encased the entire boiler. The fire grate would have been just above the two large metal drums seen at the bottom. Combustion air was drawn from the top of the boiler through passages in the brickwork. This preheated the air which increased efficiency. Vertical tubes are shown connecting upper, horizontal steam/water drums with the lower water/mud drums. Large water tubes behind the back wall of the boiler directly connect the upper and lower drums to allow cool water to circulate downward to the lower drums. The larger, horizontal drum at the top of the model collected and distributed the steam for use.

Firmenich and Stiker constructed a boiler of this design and demonstrated it at the Centennial Exposition in Philadelphia in 1876. Scientific American Magazine in June, 1878 referred to the Firmenich and Stiker boiler as a “safety steam boiler” and noted two 150 horsepower units had been installed at the Negara Starch Works in Buffalo. On October 8, 1887 a Firmenich boiler used in a flour mill in St. Louis, Missouri exploded with loss of life and significant property damage and raised questions about elements of the design.

The patent model is constructed of metal and wood painted to look like brickwork. It illustrates all of the key elements of the design. A full description of the operation of the boiler 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.

Bachelder Steam Engine Indicator

National Museum of American History
Thomas and Bushnell manufactured this steam engine indicator, serial number 482, based on a design by Joseph Bachelder, who received patent number 360644 on April 5, 1887. It consists of a brass piston, a brass cylinder, and a large drum with a coil spring and a single record. The cantilever spring is enclosed in the tube; an adjustable fulcrum renders one spring usable over a range of values. Two springs are included: one low pressure 10-25 (20-50 pounds) and one high pressure 30-90 (60-175 pounds).

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.

Krausch Engine Indicator Patent Model

National Museum of American History
This model was submitted to the U.S. Patent Office with the application for the patent issued to C. W. T. Krausch, of Chicago, Illinois, September 9, 1862, no. 36411.

The model represents an instrument designed to indicate and record speeds, draw-bar loads, boiler water levels, boiler pressures, steam-chest pressures, cylinder pressures, and conditions of the track connected with the operation of a locomotive engine and to plot these on a paper belt driven from a truck axle with a motion corresponding to the progress of the engine.

A series of levers and markers corresponding to the number of the above operations to be recorded works transversely on the paper record as the paper is advanced by the progress of the engine. The marker indicating speed is actuated by a spring-balanced bellows, the motion of which is determined by the volume of air delivered to it by small air-pump cylinders actuated by any convenient part of the engine. The other markers are actuated mechanically by a series of levers to various indicating instruments on the engine, not described.*

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.

*Reference:

This description comes from the 1939 Catalog of the Mechanical Collections of the Division of Engineering United States Museum Bulletin 173 by Frank A. Taylor.

Sciple's Patent Model of a Portable Steam Engine –1879

National Museum of American History
This model was filed with the application to the U.S. Patent Office for Patent Number 224,482 issued to Harry M Sciple of Selin's Grove, Pennsylvania on February 10, 1880. The patent was for a new and improved portable steam engine. Mr. Sciple's goals for his design were lightness, durability and low cost. He claimed his innovation was making the majority of the engine from only two castings. The first and largest was the base, steam cylinder, and steam valve. The second was the cylinder head combined with the crosshead guides. In the image of the model the steam valve is the horizontal cylinder on the side of the steam cylinder; and the crosshead and guides casting is the arch shape at the top. The piston rod is attached to the crosshead which can be seen across the arch. Another new design feature claimed by Mr. Sciple was the use of vee- shaped crosshead guides. Instead of the typical metal sliding on metal crosshead and guide design, he used rubber coated rollers attached to each end of the crosshead. The connecting rod is the inverted u-shaped hoop seen connected to a bar across the crosshead and descending on each side of the cylinder to the crankshaft. The eccentric gear is shown on the shaft just outside the base. The rod connected to it operates the steam valve via the crank arm shown.

Before the widespread use of electric motors, small high-speed steam engines such as the Sciple design were common for general light duty. Simple and dependable, such engines were cheap to build and easy to operate and maintain. They could be connected directly to pumps, generators, blowers and other machinery.

All of the key elements of the patent are illustrated in detail by the model. The patent model parts representing the large castings are made of lead. Other metal is used for the moving parts. 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.

Ericsson Steam Engine, Patent Model

National Museum of American History
This model was filed with the application to the U.S. Patent Office for Patent Number 41,612 issued to John Ericsson of New York, New York on February 16, 1864. The patent was for an improvement in reciprocating steam engines that would reduce the destructive vibration effects of then current designs.

Many marine steam engines were mounted transversely in the vessel in order to facilitate operating crank arms to turn the propeller. With each successive cycle of the engine the oscillating masses of the engine’s pistons produced high concussive forces on the engine mounts and hull of the vessel. This was more serious for engines directly driving the ship’s propeller without gearing; the engine needed to run at higher speeds thereby making the vibrations more damaging.

Mr. Ericsson’s patent design provided a rolling counter balance weight that moved in the opposite direction as the motion of the of the engine’s piston. The weight would be matched to the combined weight of the piston and its pushrods and other oscillating masses. He provided for a crank lever mechanism that would translate the motion of the piston to that of the counter balance weight.

Mr. Ericsson was a prolific inventor; his inventions included many types of steam engines and associated apparatus as well as hot air engines. He was the designer of the USS Monitor for the North during the Civil War. The Monitor engine was based on his Patent Number 20,782 of July 6, 1858 . In that patent he began to address design issues that would reduce stresses on the engine’s components and its bed. In this patent, Number 41,612, he addressed the issue of concussive force effect of that engine and showed how his counterbalancing weight concept could be applied.

The patent model is shown in the image. It is constructed of wood and brass and illustrates the major elements of the patent. A brass plate on the model is engraved “J. Ericsson, Inventor, 1863.” A spring motor causes the model to simulate actual operation with the piston moving and the counterbalancing weight moving within a hollow space in the wooden base of the model. Diagrams showing the complete design of the engine can be found in the patent document online (/www.USPTO.gov).

Porter’s Patent Model of a Steam Engine Governor – ca 1858

National Museum of American History
This model was filed with the application to the U.S. Patent Office for Patent Number 20,894 issued to Charles T. Porter of New York, New York on July 13, 1858. The patent was for an improvement in controlling the speed of a steam engine by use of a fly ball governor. This design was one of the earliest weighted flyball governors. It differed from the common fly ball governor in that the balls were of very light weight, and the governor was intended to be operated at much higher speeds of rotation. The governor included gearing that rotated the fly balls at approximately ten times the speed of the engine's rotation . The design did not suffer from the increased friction of heavy fly balls which would reduce responsiveness. The inventor claimed the advantages of his design were more sensitivity and rapid response to small changes in engine speed.

The Porter governor design was used in the Porter-Allen engine introduced about 1867, and the weighted flyball principle was widely used from then on.

The patent model is constructed of cast iron and steel. All of the key elements of the patent are illustrated by the model. It includes a hand crank to permit demonstration of actual operation. A full description of the workings of the governor and 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.

Outside Spring Steam Engine Indicator with Lanza Attachment for Continuous Recording - 1930

National Museum of American History
An engine indicator is an instrument for graphically recording the cylinder pressure versus piston displacement through an engine stroke cycle. Engineers use the resulting diagram to check the design and performance of the engine. The indicator portion of this unit is a 1930 Crosby Valve and Gage company external spring model. The advantage of the outside spring was isolation of the spring from the varying temperatures inside the cylinder. The continuous recording attachment was invented by Professor Gaetano Lanza of MIT and patented in 1908.

The advantage of continuous measurements is that accurate assessments can be made of engines which experience widely varying loads during portions of their work. A continuous recording mechanism had been patented by T. Davidson approximately a year prior to the Lanza patent. Lanza’s improvement was the replacement of cords attached to the engine’s piston rod with a rigid metal attachment. This eliminated errors and distortions caused by the cord stretching and variations in the return springs.

The introduction of the steam indicator in the late 1790s and early 1800s by James Watt and others had a great impact on the understanding of how the steam behaved inside the engine's cylinder and thereby enabled much more exacting and sophisticated designs. The devices also changed how the economics and efficiency of steam engines were portrayed and marketed. They helped the prospective owner of a machine better understand how much his fuel costs would be for a given amount of work performed. Measurement of fuel consumed and work delivered by the engine was begun by Watt, who in part justified the selling price of his engines on the amount of fuel cost the purchaser might save compared to an alternate engine.

In the early days of steam power, the method to compare engine performance was based on a concept termed the engine’s “duty”. It originally was calculated as the number of pounds of water raised one foot high per one bushel of coal consumed. The duty method was open to criticism due to its inability to take into consideration finer points of efficiency in real world applications of engines. Accurate determination of fuel used in relation to work performed has been fundamental to the design and improvement of all steam-driven prime movers ever since Watt’s time. And, the steam indicators’ key contribution was the accurate measurements of performance while the engine was actually doing the work it was designed to do. This indicator is the result of nearly 150 years of design and performance improvements. The Lanza attachment enabled accurate and continuous of monitoring of engines that experienced widely varying load conditions.

G. H. Crosby Indicator, Patent Model

National Museum of American History
This indicator was filed to the U.S. Patent Office with the application for patent no. 219149 issued to G. H. Crosby, September 2, 1879.

The model cannot be disassembled and the piston is stuck in the cylinder. It consists of a large drum with spiral spring and single record, but the linkage is different from the other Crosby indicators in the collection: a spring releases to move the drum back away from the pencil print.

The improvements claimed for this design are a jacket about the steam cylinder to prevent radiation or loss of heat from the cylinder; a method of supporting the cylinder and jacket so that each might expand freely when heated; the carrying of the rotary drum on a lever so that it could be moved up to and away from the marker; and a peculiar parallel motion for effecting the straight line motion of the marker in which “the lever is connected with the piston-rod by a join, and not indirectly by a link, as in the Richards 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.

*Reference:

This description comes from the 1939 Catalog of the Mechanical Collections of the Division of Engineering United States Museum Bulletin 173 by Frank A. Taylor.

Model, Airplane, Kit, Lindbergh, King Collection

National Air and Space Museum
The pieces for this model kit are gray molded plastic that are unassembled. There is also a small plastic piece in the shape of a pilot. The instruction manual is a two sided piece of paper with diagrams of key steps and text for each step. Water decals are also included on a single sheet. The box for the model is a clamshell design with an image of the Spirit of St. Louis on the top. The Air Lines model company's logo is on the left of the top. 1/72 Scale.

On May 20-21, 1927, Charles Lindbergh literally flew into history when he crossed the Atlantic Ocean in his Ryan NYP Spirit of St. Louis, thus becoming the first pilot to fly solo and nonstop from New York to Paris. This flight made Lindbergh a household name and catapulted him into fame and celebrity. The objects of popular culture in the National Collection display everything from ashtrays to wristwatches reflect the public adulation for Lindbergh and the powerful commercial response to his celebrity. More than 75 years after the Spirit's historic flight, Lindbergh's name still has the power help sell manufactured goods.

Hottinger Aneroid Barometer

National Museum of American History
Jakob Goldschmid, a mechanic in Zurich, Switzerland, designed an aneroid barometer that promised great stability, but that had to be adjusted before each reading. This example was manufactured by the firm run by Rudolf Hottinger, who was Goldschmid’s son-in-law and successor. It has an eyepiece for viewing the internal mechanism, and a thermometer for determining the internal temperature. The face is marked “Ship-Barometer / No. 116” and “HOTTINGER & CO. / ZURICH” and also carries a scale of correction tables. A printed card with diagram and instructions for use, in English, is mounted inside the case. Ref.: "The Goldschmid Aneroid," Van Nostrand's Engineering Magazine 25 (1881): 300-303.

Alfred Vail's Electromagnetic Telegraph Notes

Smithsonian Archives - History Div
Alfred Vail was a key partner to American inventor Samuel Morse and is credited with designing the machine and alpha code used in the creation of the electromagnetic telegraph.

For other materials relevant to Vail's work, see Negative Numbers SIA2011-0824, SIA2011-0825, and SIA2011-0827 to SIA2011-0830. For letters between Vail, Morse, and first Smithsonian Secretary Joseph Henry, see Negative Numbers SIA2011-0814 to SIA2011-0823.

The page on the left contains Alfred Vail's notes about magnetic forces and magnetism in relation to the electromagnetic telegraph. The page on the right is a diagram drawn by Vail of the telegraph line between Pittsburgh, Pennsylvania and Washington , D.C.

Kollsman Sensitive Altimeter

National Air and Space Museum
Offset Lithograph: 3 diagrams showing how the various pieces of the sensitive alitmeter work.

Fly Now: The National Air and Space Museum Poster Collection

Throughout their history, posters have been a significant means of mass communication, often with striking visual effect. Wendy Wick Reaves, the Smithsonian Portrait Gallery Curator of Prints and Drawings, comments that "sometimes a pictorial poster is a decorative masterpiece-something I can't walk by without a jolt of aesthetic pleasure. Another might strike me as extremely clever advertising … But collectively, these 'pictures of persuasion,' as we might call them, offer a wealth of art, history, design, and popular culture for us to understand. The poster is a familiar part of our world, and we intuitively understand its role as propaganda, promotion, announcement, or advertisement."

Reaves' observations are especially relevant for the impressive array of aviation posters in the National Air and Space Museum's 1300+ artifact collection. Quite possibly the largest publicly-held collection of its kind in the United States, the National Air and Space Museum's posters focus primarily on advertising for aviation-related products and activities. Among other areas, the collection includes 19th-century ballooning exhibition posters, early 20th-century airplane exhibition and meet posters, and twentieth-century airline advertisements.

The posters in the collection represent printing technologies that include original lithography, silkscreen, photolithography, and computer-generated imagery. The collection is significant both for its aesthetic value and because it is a unique representation of the cultural, commercial and military history of aviation. The collection represents an intense interest in flight, both public and private, during a significant period of its technological and social development.

Kollsman Tachometers

National Air and Space Museum
Offset Lithograph: 2 diagrams; one showing centrifugal tachometer and other magnetic tachometer.

Fly Now: The National Air and Space Museum Poster Collection

Throughout their history, posters have been a significant means of mass communication, often with striking visual effect. Wendy Wick Reaves, the Smithsonian Portrait Gallery Curator of Prints and Drawings, comments that "sometimes a pictorial poster is a decorative masterpiece-something I can't walk by without a jolt of aesthetic pleasure. Another might strike me as extremely clever advertising … But collectively, these 'pictures of persuasion,' as we might call them, offer a wealth of art, history, design, and popular culture for us to understand. The poster is a familiar part of our world, and we intuitively understand its role as propaganda, promotion, announcement, or advertisement."

Reaves' observations are especially relevant for the impressive array of aviation posters in the National Air and Space Museum's 1300+ artifact collection. Quite possibly the largest publicly-held collection of its kind in the United States, the National Air and Space Museum's posters focus primarily on advertising for aviation-related products and activities. Among other areas, the collection includes 19th-century ballooning exhibition posters, early 20th-century airplane exhibition and meet posters, and twentieth-century airline advertisements.

The posters in the collection represent printing technologies that include original lithography, silkscreen, photolithography, and computer-generated imagery. The collection is significant both for its aesthetic value and because it is a unique representation of the cultural, commercial and military history of aviation. The collection represents an intense interest in flight, both public and private, during a significant period of its technological and social development.

Painting - Heptagon 1:3:3 Triangle

National Museum of American History
This painting is part of Crockett Johnson's exploration of the properties of the heptagon, extended to include a 14-sided regular polygon. The design of the painting is shown in his figure, which includes many of the line segments in the painting. Here Crockett Johnson argues that the triangle ABF in the figure is the one he sought, with angle FAB being one seventh of pi. Segment CD in the figure, which appears in the painting, is the length of the edge of a regular 14-sided figure inscribed in a portion of the larger circle shown.

The painting, of oil or acrylic on masonite, is number 105 in the series. It is drawn in shades of cream, blue, and purple on a light purple background. It has a metal frame and is unsigned.

Grand Central Station #2

Smithsonian American Art Museum
Jim Campbell’s Grand Central Station #2 consists of a grid of LED lights that illuminate an image of the main terminal at Grand Central Station in New York City. The point of view, hovering above the marble floor as shadows pass through the terminal, mimics that of contemporary surveillance systems. The artwork functions as a layered schematic diagram of the structures of human psychology and memory, and challenges technology’s ability to accurately represent the human experience.

Watch This!: Revelations in Media Art, 2015

Smith’s Patent Model of a Split Rim Pulley, ca 1871

National Museum of American History
This model was filed with the application to the U.S. Patent Office for Patent Number 111,582 issued to Scott A. Smith of Philadelphia, Pennsylvania on February 7, 1871. The patent was for an improvement in pulleys of the type known as “half-pulleys.” Half-pulleys are constructed so that they can be separated into two pieces to facilitate installation and removal without disturbing other components on the shaft.

Mr. Smith’s claimed improvement dealt with the method for breaking the two halves of the rim apart and then securing them after installation on the shaft. He called for the pulley casting to have notches in the inside of the rim and hub where the halves separate. The resulting thin spots in the metal would produce rough edges when the casting was broken apart, and these edges would interlock and thus help keep the rims from overlapping when bolted back together.

The patent model is shown in the image. It is made of cast iron. All of the key elements of the patent are illustrated by the model. Diagrams showing the complete design can be found in the patent document online (/www.USPTO.gov).

Fixing a Fold-Out Plate

Smithsonian Libraries

Fold-out plates are often used to feature important illustrations or diagrams in many books related to science, technology, and history. Though a fold-out is designed to be frequently folded and unfolded, the stress on the creased fold lines from constant handling often causes the paper to break. A book from the Smithsonian Libraries’s Research Annex more »

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