Wednesday, August 12, 2009

Laser-diode recording process




The invention: Video and audio playback system that uses a lowpower
laser to decode information digitally stored on reflective
disks.
The organization behind the invention:
The Philips Corporation, a Dutch electronics firm
The Development of Digital Systems
Since the advent of the computer age, it has been the goal of
many equipment manufacturers to provide reliable digital systems
for the storage and retrieval of video and audio programs. A need
for such devices was perceived for several reasons. Existing storage
media (movie film and 12-inch, vinyl, long-playing records) were
relatively large and cumbersome to manipulate and were prone to
degradation, breakage, and unwanted noise. Thus, during the late
1960’s, two different methods for storing video programs on disc
were invented. A mechanical system was demonstrated by the
Telefunken Company, while the Radio Corporation of America
(RCA) introduced an electrostatic device (a device that used static
electricity). The first commercially successful system, however, was
developed during the mid-1970’s by the Philips Corporation.
Philips devoted considerable resources to creating a digital video
system, read by light beams, which could reproduce an entire feature-
length film from one 12-inch videodisc. An integral part of this
innovation was the fabrication of a device small enough and fast
enough to read the vast amounts of greatly compacted data stored
on the 12-inch disc without introducing unwanted noise. Although
Philips was aware of the other formats, the company opted to use an
optical scanner with a small “semiconductor laser diode” to retrieve
the digital information. The laser diode is only a fraction of a millimeter
in size, operates quite efficiently with high amplitude and relatively
low power (0.1 watt), and can be used continuously. Because
this configuration operates at a high frequency, its informationcarrying
capacity is quite large.Although the digital videodisc system (called “laservision”) works
well, the low level of noise and the clear images offered by this system
were masked by the low quality of the conventional television
monitors on which they were viewed. Furthermore, the high price
of the playback systems and the discs made them noncompetitive
with the videocassette recorders (VCRs) that were then capturing
the market for home systems. VCRs had the additional advantage
that programs could be recorded or copied easily. The Philips Corporation
turned its attention to utilizing this technology in an area
where low noise levels and high quality would be more readily apparent—
audio disc systems. By 1979, they had perfected the basic
compact disc (CD) system, which soon revolutionized the world of
stereophonic home systems.
Reading Digital Discs with Laser Light
Digital signals (signals composed of numbers) are stored on
discs as “pits” impressed into the plastic disc and then coated with a
thin reflective layer of aluminum. A laser beam, manipulated by
delicate, fast-moving mirrors, tracks and reads the digital information
as changes in light intensity. These data are then converted to a
varying electrical signal that contains the video or audio information.
The data are then recovered by means of a sophisticated
pickup that consists of the semiconductor laser diode, a polarizing
beam splitter, an objective lens, a collective lens system, and a
photodiode receiver. The beam from the laser diode is focused by a
collimator lens (a lens that collects and focuses light) and then
passes through the polarizing beam splitter (PBS). This device acts
like a one-way mirror mounted at 45 degrees to the light path. Light
from the laser passes through the PBS as if it were a window, but the
light emerges in a polarized state (which means that the vibration of
the light takes place in only one plane). For the beam reflected from
the CD surface, however, the PBS acts like a mirror, since the reflected
beam has an opposite polarization. The light is thus deflected
toward the photodiode detector. The objective lens is needed
to focus the light onto the disc surface. On the outer surface of the
transparent disc, the main spot of light has a diameter of 0.8 millimeter,
which narrows to only 0.0017 millimeter at the reflective surface. At the surface, the spot is about three times the size of the microscopic
pits (0.0005 millimeter).
The data encoded on the disc determine the relative intensity of
the reflected light, on the basis of the presence or absence of pits.
When the reflected laser beam enters the photodiode, a modulated
light beam is changed into a digital signal that becomes an analog
(continuous) audio signal after several stages of signal processing
and error correction.
Consequences
The development of the semiconductor laser diode and associated
circuitry for reading stored information has made CD audio
systems practical and affordable. These systems can offer the quality
of a live musical performance with a clarity that is undisturbed
by noise and distortion. Digital systems also offer several other significant
advantages over analog devices. The dynamic range (the
difference between the softest and the loudest signals that can be
stored and reproduced) is considerably greater in digital systems. In
addition, digital systems can be copied precisely; the signal is not
degraded by copying, as is the case with analog systems. Finally,
error-correcting codes can be used to detect and correct errors in
transmitted or reproduced digital signals, allowing greater precision
and a higher-quality output sound.
Besides laser video systems, there are many other applications
for laser-read CDs. Compact disc read-only memory (CD-ROM) is
used to store computer text. One standard CD can store 500 megabytes
of information, which is about twenty times the storage of a
hard-disk drive on a typical home computer. Compact disc systems
can also be integrated with conventional televisions (called CD-V)
to present twenty minutes of sound and five minutes of sound with
picture. Finally, CD systems connected with a computer (CD-I) mix
audio, video, and computer programming. These devices allow the
user to stop at any point in the program, request more information,
and receive that information as sound with graphics, film clips, or
as text on the screen.

Laser



The invention: Taking its name from the acronym for light amplification
by the stimulated emission of radiation, a laser is a
beam of electromagnetic radiation that is monochromatic, highly
directional, and coherent. Lasers have found multiple applications
in electronics, medicine, and other fields.
The people behind the invention:
Theodore Harold Maiman (1927- ), an American physicist
Charles Hard Townes (1915- ), an American physicist who
was a cowinner of the 1964 Nobel Prize in Physics
Arthur L. Schawlow (1921-1999), an American physicist,
cowinner of the 1981 Nobel Prize in Physics
Mary Spaeth (1938- ), the American inventor of the tunable
laser
Coherent Light
Laser beams differ from other forms of electromagnetic radiation
in being consisting of a single wavelength, being highly directional,
and having waves whose crests and troughs are aligned. A laser
beam launched from Earth has produced a spot a few kilometers
wide on the Moon, nearly 400,000 kilometers away. Ordinary light
would have spread much more and produced a spot several times
wider than the Moon. Laser light can also be concentrated so as to
yield an enormous intensity of energy, more than that of the surface
of the Sun, an impossibility with ordinary light.
In order to appreciate the difference between laser light and ordinary
light, one must examine how light of any kind is produced. An
ordinary light bulb contains atoms of gas. For the bulb to light up,
these atoms must be excited to a state of energy higher then their
normal, or ground, state. This is accomplished by sending a current
of electricity through the bulb; the current jolts the atoms into the
higher-energy state. This excited state is unstable, however, and the
atoms will spontaneously return to their ground state by ridding
themselves of excess energy.As these atoms emit energy, light is produced. The light emitted
by a lamp full of atoms is disorganized and emitted in all directions
randomly. This type of light, common to all ordinary sources, from
fluorescent lamps to the Sun, is called “incoherent light.”
Laser light is different. The excited atoms in a laser emit their excess
energy in a unified, controlled manner. The atoms remain in the
excited state until there are a great many excited atoms. Then, they
are stimulated to emit energy, not independently, but in an organized
fashion, with all their light waves traveling in the same direction,
crests and troughs perfectly aligned. This type of light is called
“coherent light.”
Theory to Reality
In 1958, Charles Hard Townes of Columbia University, together
with Arthur L. Schawlow, explored the requirements of the laser in
a theoretical paper. In the Soviet Union, F. A. Butayeva and V. A.
Fabrikant had amplified light in 1957 using mercury; however, their
work was not published for two years and was not published in a
scientific journal. The work of the Soviet scientists, therefore, received virtually no attention in the Western world.
In 1960, Theodore Harold Maiman constructed the first laser in
the United States using a single crystal of synthetic pink ruby,
shaped into a cylindrical rod about 4 centimeters long and 0.5 centimeter
across. The ends, polished flat and made parallel to within
about a millionth of a centimeter, were coated with silver to make
them mirrors.
It is a property of stimulated emission that stimulated light
waves will be aligned exactly (crest to crest, trough to trough, and
with respect to direction) with the radiation that does the stimulating.
From the group of excited atoms, one atom returns to its ground state, emitting light. That light hits one of the other exited atoms and
stimulates it to fall to its ground state and emit light. The two light
waves are exactly in step. The light from these two atoms hits other
excited atoms, which respond in the same way, “amplifying” the total
sum of light.
If the first atom emits light in a direction parallel to the length of
the crystal cylinder, the mirrors at both ends bounce the light waves
back and forth, stimulating more light and steadily building up an
increasing intensity of light. The mirror at one end of the cylinder is
constructed to let through a fraction of the light, enabling the light to
emerge as a straight, intense, narrow beam.
Consequences
When the laser was introduced, it was an immediate sensation. In
the eighteen months following Maiman’s announcement that he had
succeeded in producing a working laser, about four hundred companies
and several government agencies embarked on work involving
lasers. Activity centered on improving lasers, as well as on exploring
their applications. At the same time, there was equal activity in publicizing
the near-miraculous promise of the device, in applications covering
the spectrum from “death” rays to sight-saving operations. A
popular film in the James Bond series, Goldfinger (1964), showed the
hero under threat of being sliced in half by a laser beam—an impossibility
at the time the film was made because of the low power-output
of the early lasers.
In the first decade after Maiman’s laser, there was some disappointment.
Successful use of lasers was limited to certain areas of
medicine, such as repairing detached retinas, and to scientific applications,
particularly in connection with standards: The speed of
light was measured with great accuracy, as was the distance to the
Moon. By 1990, partly because of advances in other fields, essentially
all the laser’s promise had been fulfilled, including the death
ray and James Bond’s slicer. Yet the laser continued to find its place
in technologies not envisioned at the time of the first laser. For example,
lasers are now used in computer printers, in compact disc
players, and even in arterial surgery.

Monday, August 10, 2009

Laminated glass




The invention: Double sheets of glass separated by a thin layer of
plastic sandwiched between them.
The people behind the invention:
Edouard Benedictus (1879-1930), a French artist
Katherine Burr Blodgett (1898-1979), an American physicist
The Quest for Unbreakable Glass
People have been fascinated for centuries by the delicate transparency
of glass and the glitter of crystals. They have also been frustrated
by the brittleness and fragility of glass. When glass breaks, it
forms sharp pieces that can cut people severely. During the 1800’s
and early 1900’s, a number of people demonstrated ways to make
“unbreakable” glass. In 1855 in England, the first “unbreakable”
glass panes were made by embedding thin wires in the glass. The
embedded wire grid held the glass together when it was struck or
subjected to the intense heat of a fire.Wire glass is still used in windows
that must be fire resistant. The concept of embedding the wire
within a glass sheet so that the glass would not shatter was a predecessor
of the concept of laminated glass.
A series of inventors in Europe and the United States worked on
the idea of using a durable, transparent inner layer of plastic between
two sheets of glass to prevent the glass from shattering when it was
dropped or struck by an impact. In 1899, Charles E.Wade of Scranton,
Pennsylvania, obtained a patent for a kind of glass that had a sheet or
netting of mica fused within it to bind it. In 1902, Earnest E. G. Street
of Paris, France, proposed coating glass battery jars with pyroxylin
plastic (celluloid) so that they would hold together if they cracked. In
Swindon, England, in 1905, John Crewe Wood applied for a patent
for a material that would prevent automobile windshields from shattering
and injuring people when they broke. He proposed cementing
a sheet of material such as celluloid between two sheets of glass.
When the window was broken, the inner material would hold the
glass splinters together so that they would not cut anyone.Remembering a Fortuitous Fall
In his patent application, Edouard Benedictus described himself
as an artist and painter. He was also a poet, musician, and
philosopher who was descended from the philosopher Baruch
Benedictus Spinoza; he seemed an unlikely contributor to the
progress of glass manufacture. In 1903, Benedictus was cleaning his laboratory when he dropped a glass bottle that held a nitrocellulose
solution. The solvents, which had evaporated during the
years that the bottle had sat on a shelf, had left a strong celluloid
coating on the glass. When Benedictus picked up the bottle, he was
surprised to see that it had not shattered: It was starred, but all the
glass fragments had been held together by the internal celluloid
coating. He looked at the bottle closely, labeled it with the date
(November, 1903) and the height from which it had fallen, and put
it back on the shelf.
One day some years later (the date is uncertain), Benedictus became
aware of vehicular collisions in which two young women received
serious lacerations from broken glass. He wrote a poetic account
of a daydream he had while he was thinking intently about
the two women. He described a vision in which the faintly illuminated
bottle that had fallen some years before but had not shattered
appeared to float down to him from the shelf. He got up, went into
his laboratory, and began to work on an idea that originated with his
thoughts of the bottle that would not splinter.
Benedictus found the old bottle and devised a series of experiments
that he carried out until the next evening. By the time he had
finished, he had made the first sheet of Triplex glass, for which he
applied for a patent in 1909. He also founded the Société du Verre
Triplex (The Triplex Glass Society) in that year. In 1912, the Triplex
Safety Glass Company was established in England. The company
sold its products for military equipment in World War I, which began
two years later.
Triplex glass was the predecessor of laminated glass. Laminated
glass is composed of two or more sheets of glass with a thin
layer of plastic (usually polyvinyl butyral, although Benedictus
used pyroxylin) laminated between the glass sheets using pressure
and heat. The plastic layer will yield rather than rupture when subjected
to loads and stresses. This prevents the glass from shattering
into sharp pieces. Because of this property, laminated glass is also
known as “safety glass.”
Impact
Even after the protective value of laminated glass was known,the product was not widely used for some years. There were a number
of technical difficulties that had to be solved, such as the discoloring
of the plastic layer when it was exposed to sunlight; the relatively
high cost; and the cloudiness of the plastic layer, which
obscured vision—especially at night. Nevertheless, the expanding
automobile industry and the corresponding increase in the number
of accidents provided the impetus for improving the qualities and
manufacturing processes of laminated glass. In the early part of the
century, almost two-thirds of all injuries suffered in automobile accidents
involved broken glass.
Laminated glass is used in many applications in which safety is
important. It is typically used in all windows in cars, trucks, ships,
and aircraft. Thick sheets of bullet-resistant laminated glass are
used in banks, jewelry displays, and military installations. Thinner
sheets of laminated glass are used as security glass in museums, libraries,
and other areas where resistance to break-in attempts is
needed. Many buildings have large ceiling skylights that are made
of laminated glass; if the glass is damaged, it will not shatter, fall,
and hurt people below. Laminated glass is used in airports, hotels,
and apartments in noisy areas and in recording studios to reduce
the amount of noise that is transmitted. It is also used in safety goggles
and in viewing ports at industrial plants and test chambers.
Edouard Benedictus’s recollection of the bottle that fell but did not
shatter has thus helped make many situations in which glass is used
safer for everyone.

Iron lung




The invention: Amechanical respirator that saved the lives of victims
of poliomyelitis.
The people behind the invention:
Philip Drinker (1894-1972), an engineer who made many
contributions to medicine
Louis Shaw (1886-1940), a respiratory physiologist who
assisted Drinker
Charles F. McKhann III (1898-1988), a pediatrician and
founding member of the American Board of Pediatrics
A Terrifying Disease
Poliomyelitis (polio, or infantile paralysis) is an infectious viral
disease that damages the central nervous system, causing paralysis
in many cases. Its effect results from the destruction of neurons
(nerve cells) in the spinal cord. In many cases, the disease produces
crippled limbs and the wasting away of muscles. In others, polio results
in the fatal paralysis of the respiratory muscles. It is fortunate
that use of the Salk and Sabin vaccines beginning in the 1950’s has
virtually eradicated the disease.
In the 1920’s, poliomyelitis was a terrifying disease. Paralysis of
the respiratory muscles caused rapid death by suffocation, often
within only a few hours after the first signs of respiratory distress
had appeared. In 1929, Philip Drinker and Louis Shaw, both of Harvard
University, reported the development of a mechanical respirator
that would keep those afflicted with the disease alive for indefinite
periods of time. This device, soon nicknamed the “iron lung,”
helped thousands of people who suffered from respiratory paralysis
as a result of poliomyelitis or other diseases.
Development of the iron lung arose after Drinker, then an assistant
professor in Harvard’s Department of Industrial Hygiene, was
appointed to a Rockefeller Institute commission formed to improve
methods for resuscitating victims of electric shock. The best-known
use of the iron lung—treatment of poliomyelitis—was a result of
numerous epidemics of the disease that occurred from 1898 until the 1920’s, each leaving thousands of Americans paralyzed.
The concept of the iron lung reportedly arose from Drinker’s observation
of physiological experiments carried out by Shaw and
Drinker’s brother, Cecil. The experiments involved the placement
of a cat inside an airtight box—a body plethysmograph—with the
cat’s head protruding from an airtight collar. Shaw and Cecil Drinker
then measured the volume changes in the plethysmograph to identify
normal breathing patterns. Philip Drinker then placed cats paralyzed
by curare inside plethysmographies and showed that they
could be kept breathing artificially by use of air from a hypodermic
syringe connected to the device.
Next, they proceeded to build a human-sized plethysmographlike
machine, with a five-hundred-dollar grant from the New York
Consolidated Gas Company. This was done by a tinsmith and the
Harvard Medical School machine shop.
Breath for Paralyzed Lungs
The first machine was tested on Drinker and Shaw, and after several
modifications were made, a workable iron lung was made
available for clinical use. This machine consisted of a metal cylinder
large enough to hold a human being. One end of the cylinder, which
contained a rubber collar, slid out on casters along with a stretcher
on which the patient was placed. Once the patient was in position
and the collar was fitted around the patient’s neck, the stretcher was
pushed back into the cylinder and the iron lung was made airtight.
The iron lung then “breathed” for the patient by using an electric
blower to remove and replace air alternatively inside the machine.
In the human chest, inhalation occurs when the diaphragm contracts
and powerful muscles (which are paralyzed in poliomyelitis
sufferers) expand the rib cage. This lowers the air pressure in the
lungs and allows inhalation to occur. In exhalation, the diaphragm
and chest muscles relax, and air is expelled as the chest cavity returns
to its normal size. In cases of respiratory paralysis treated with
an iron lung, the air coming into or leaving the iron lung alternately
compressed the patient’s chest, producing artificial exhalation, and
the allowed it to expand to so that the chest could fill with air. In this
way, iron lungs “breathed” for the patients using them.Careful examination of each patient was required to allow technicians
to adjust the rate of operation of the machine. Acooling system
and ports for drainage lines, intravenous lines, and the other
apparatus needed to maintain a wide variety of patients were included
in the machine.
The first person treated in an iron lung was an eight-year-old girl
afflicted with respiratory paralysis resulting from poliomyelitis. The
iron lung kept her alive for five days. Unfortunately, she died from
heart failure as a result of pneumonia. The next iron lung patient, a
Harvard University student, was confined to the machine for several
weeks and later recovered enough to resume a normal life.

The Internet



The invention: 



A worldwide network of interlocking computer

systems, developed out of a U.S. government project to improve

military preparedness.



The people behind the invention:



Paul Baran, a researcher for the RAND corporation

Vinton G. Cerf (1943- ), an American computer scientist

regarded as the “father of the Internet”








Cold War Computer Systems



In 1957, the world was stunned by the launching of the satellite

Sputnik I by the Soviet Union. The international image of the United

States as the world’s technology superpower and its perceived edge

in the ColdWar were instantly brought into question. As part of the

U.S. response, the Defense Department quickly created the Advanced

Research Projects Agency (ARPA) to conduct research into

“command, control, and communications” systems. Military planners

in the Pentagon ordered ARPA to develop a communications

network that would remain usable in the wake of a nuclear attack.

The solution, proposed by Paul Baran, a scientist at the RAND Corporation,

was the creation of a network of linked computers that

could route communications around damage to any part of the system.

Because the centralized control of data flow by major “hub”

computers would make such a system vulnerable, the system could

not have any central command, and all surviving points had to be

able to reestablish contact following an attack on any single point.

This redundancy of connectivity (later known as “packet switching”)

would not monopolize a single circuit for communications, as

telephones do, but would automatically break up computer messages

into smaller packets, each of which could reach a destination

by rerouting along different paths.

ARPA then began attempting to link university computers over

telephone lines. The historic connecting of four sites conducting

ARPAresearch was accomplished in 1969 at a computer laboratory

at the University of California at Los Angeles (UCLA), which was

connected to computers at the University of California at Santa

Barbara, the Stanford Research Institute, and the University of Utah.

UCLA graduate student Vinton Cerf played a major role in establishing

the connection, which was first known as “ARPAnet.” By

1971, more than twenty sites had been connected to the network, including

supercomputers at the Massachusetts Institute of Technology

and Harvard University; by 1981, there were more than two

hundred computers on the system.





The Development of the Internet



Because factors such as equipment failure, overtaxed telecommunications

lines, and power outages can quickly reduce or abort

(“crash”) computer network performance, the ARPAnet managers

and others quickly sought to build still larger “internetting” projects.

In the late 1980’s, the National Science Foundation built its

own network of five supercomputer centers to give academic researchers

access to high-power computers that had previously been

available only to military contractors. The “NSFnet” connected university

networks by linking them to the closest regional center; its

development put ARPAnet out of commission in 1990. The economic

savings that could be gained from the use of electronic mail

(“e-mail”), which reduced postage and telephone costs, were motivation

enough for many businesses and institutions to invest in

hardware and network connections.

The evolution of ARPAnet and NSFnet eventually led to the creation

of the “Internet,” an international web of interconnected government,

education, and business computer networks that has been

called “the largest machine ever constructed.” Using appropriate

software, a computer terminal or personal computer can send and

receive data via an “Internet Protocol” packet (an electronic envelope

with an address). Communications programs on the intervening

networks “read” the addresses on packets moving through the

Internet and forward the packets toward their destinations. From

approximately one thousand networks in the mid-1980’s, the Internet

grew to an estimated thirty thousand connected networks by

1994, with majority of Internet users live in the United States and Europe, but

the Internet has continued to expand internationally as telecommunications

lines are improved in other countries.



Impact



Most individual users access the Internet through modems attached

to their home personal computers by subscribing to local area

networks. These services make information sources available such as

on-line encyclopedias and magazines and embrace electronic discussion

groups and bulletin boards on nearly every specialized interest

area imaginable. Many universities converted large libraries to electronic

form for Internet distribution, with an ambitious example being

Cornell University’s conversion to electronic form of more than

100,000 books on the development of America’s infrastructure.

Numerous corporations and small businesses soon began to

market their products and services over the Internet. Problems soon

became apparent with the commercial use of the new medium,

however, as the protection of copyrighted material proved to be difficult;

data and other text available on the system can be “downloaded,”

or electronically copied. To protect their resources from

unauthorized use via the Internet, therefore, most companies set up

a “firewall” computer to screen incoming communications.

The economic policies of the Bill Clinton administration highlighted

the development of the “information superhighway” for

improving the delivery of social services and encouraging new

businesses; however, many governmental agencies and offices, including

the U.S. Senate and House of Representative, have been

slow to install high-speed fiber-optic network links. Nevertheless,

the Internet soon came to contain numerous information sites to improve

public access to the institutions of government.

are improved in other countries.



Vinton Cerf



Although Vinton Cerf is widely hailed as the “father of the

Internet,” he himself disavows that honor. He has repeatedly

emphasized that the Internet was built on the work of countless

others, and that he and his partner merely happened to make a

crucial contribution at a turning point in Internet development.

The path leading Cerf to the Internet began early. He was

born in New Haven, Connecticut, in 1943. He read widely, devouring

L. Frank Baum’s Oz books and science fiction novels—

especially those dealing with real-science themes. When he was

ten, a book called The Boy Scientist fired his interest in science.

After starting high school in Los Angeles in 1958, he got his first

glimpse of computers, which were very different devices in

those days. During a visit to a Santa Monica lab, he inspected a

computer filling three rooms with wires and vacuum tubes that

analyzed data from a Canadian radar system built to detect

sneak missile attacks from the Soviet Union. Two years later he

and a friend began programming a paper-tape computer at

UCLA while they were still in high school.

After graduating from Stanford University in 1965 with a

degree in computer science, Cerf worked for IBM for two years,

then entered graduate school at UCLA. His work on multiprocessing

computer systems got sidetracked when a Defense

Department request came in asking for help on a packet-switching

project. This new project drew him into the brand-new field

of computer networking on a system that became known as the

ARPAnet. In 1972 Cerf returned to Stanford as an assistant professor.

There he and a colleague, Robert Kahn, developed the

concepts and protocols that became the basis of the modern Internet—

a term they coined in a paper they delivered in 1974.

Afterward Cerf made development of the Internet the focus

of his distinguished career, and he later moved back into the

business world. In 1994 he returned to MCI as senior vice president

of Internet architecture. Meanwhile, he founded the Internet

Society in 1992 and the Internet Societal Task Force in 1999.







See also: Cell phone; Communications satellite; Fax machine;

Personal computer.

Internal combustion engine






The invention: The most common type of engine in automobiles
and many other vehicles, the internal combusion engine is characterized
by the fact that it burns its liquid fuelly internally—in
contrast to engines, such as the steam engine, that burn fuel in external
furnaces.
The people behind the invention:
Sir Harry Ralph Ricardo (1885-1974), an English engineer
Oliver Thornycroft (1885-1956), an engineer and works manager
Sir David Randall Pye (1886-1960), an engineer and
administrator
Sir Robert Waley Cohen (1877-1952), a scientist and industrialist
The Internal Combustion Engine: 1900-1916
By the beginning of the twentieth century, internal combustion
engines were almost everywhere. City streets in Berlin, London,
and New York were filled with automobile and truck traffic; gasoline-
and diesel-powered boat engines were replacing sails; stationary
steam engines for electrical generation were being edged out by
internal combustion engines. Even aircraft use was at hand: To
progress from theWright brothers’ first manned flight in 1903 to the
fighting planes ofWorldWar I took only a little more than a decade.
The internal combustion engines of the time, however, were
primitive in design. They were heavy (10 to 15 pounds per output
horsepower, as opposed to 1 to 2 pounds today), slow (typically
1,000 or fewer revolutions per minute or less, as opposed to 2,000 to
5,000 today), and extremely inefficient in extracting the energy content
of their fuel. These were not major drawbacks for stationary applications,
or even for road traffic that rarely went faster than 30 or
40 miles per hour, but the advent of military aircraft and tanks demanded
that engines be made more efficient.Engine and Fuel Design
Harry Ricardo, son of an architect and grandson (on his mother’s
side) of an engineer, was a central figure in the necessary redesign of
internal combustion engines. As a schoolboy, he built a coal-fired
steam engine for his bicycle, and at Cambridge University he produced
a single-cylinder gasoline motorcycle, incorporating many of
his own ideas, which won a fuel-economy competition when it traveled
almost 40 miles on a quart of gasoline. He also began development
of a two-cycle engine called the “Dolphin,” which later was
produced for use in fishing boats and automobiles. In fact, in 1911,
Ricardo took his new bride on their honeymoon trip in a Dolphinpowered
car.
The impetus that led to major engine research came in 1916
when Ricardo was an engineer in his family’s firm. The British
government asked for newly designed tank engines, which had to
operate in the dirt and mud of battle, at a tilt of up to 35 degrees,
and could not give off telltale clouds of blue oil smoke. Ricardo
solved the problem with a special piston design and with air circulation
around the carburetor and within the engine to keep the oil
cool.
Design work on the tank engines turned Ricardo into a fullfledged
research engineer. In 1917, he founded his own company,
and a remarkable series of discoveries quickly followed. He investigated
the problem of detonation of the fuel-air mixture in the internal
combustion cylinder. The mixture is supposed to be ignited
by the spark plug at the top of the compression stroke, with a controlled
flame front spreading at a rate about equal to the speed of
the piston head as it moves downward in the power stroke. Some
fuels, however, detonated (ignited spontaneously throughout the
entire fuel-air mixture) as a result of the compression itself, causing
loss of fuel efficiency and damage to the engine.
With the cooperation of RobertWaley Cohen of Shell Petroleum,
Ricardo evaluated chemical mixtures of fuels and found that paraffins
(such as n-heptane, the current low-octane standard) detonated
readily, but aromatics such as toluene were nearly immune to detonation.
He established a “toluene number” rating to describe the
tendency of various fuels to detonate; this number was replaced in the 1920’s by the “octane number” devised by Thomas Midgley at
the Delco laboratories in Dayton, Ohio.
The fuel work was carried out in an experimental engine designed
by Ricardo that allowed direct observation of the flame front
as it spread and permitted changes in compression ratio while the
engine was running. Three principles emerged from the investigation:
the fuel-air mixture should be admitted with as much turbulence
as possible, for thorough mixing and efficient combustion; the
spark plug should be centrally located to prevent distant pockets of
the mixture from detonating before the flame front reaches them;
and the mixture should be kept as cool as possible to prevent detonation.
These principles were then applied in the first truly efficient sidevalve
(“L-head”) engine—that is, an engine with the valves in a
chamber at the side of the cylinder, in the engine block, rather than
overhead, in the engine head. Ricardo patented this design, and after
winning a patent dispute in court in 1932, he received royalties
or consulting fees for it from engine manufacturers all over the
world.Impact
The side-valve engine was the workhorse design for automobile
and marine engines until after World War II. With its valves actuated
directly by a camshaft in the crankcase, it is simple, rugged,
and easy to manufacture. Overhead valves with overhead camshafts
are the standard in automobile engines today, but the sidevalve
engine is still found in marine applications and in small engines
for lawn mowers, home generator systems, and the like. In its
widespread use and its decades of employment, the side-valve engine
represents a scientific and technological breakthrough in the
twentieth century.
Ricardo and his colleagues, Oliver Thornycroft and D. R. Pye,
went on to create other engine designs—notably, the sleeve-valve
aircraft engine that was the basic pattern for most of the great British
planes of World War II and early versions of the aircraft jet engine.
For his technical advances and service to the government, Ricardo
was elected a Fellow of the Royal Society in 1929, and he was
knighted in 1948.

Monday, August 3, 2009

Interchangeable parts




The invention: 




A key idea in the late Industrial Revolution, the

interchangeability of parts made possible mass production of

identical products.





The people behind the invention:



Henry M. Leland (1843-1932), president of Cadillac Motor Car

Company in 1908, known as a master of precision

Frederick Bennett, the British agent for Cadillac Motor Car

Company who convinced the Royal Automobile Club to run

the standardization test at Brooklands, England

Henry Ford (1863-1947), founder of Ford Motor Company who

introduced the moving assembly line into the automobile

industry in 1913








An American Idea



Mass production is a twentieth century methodology that for the

most part is a result of nineteenth century ideas. It is a phenomenon

that, although its origins were mostly American, has consequently

changed the entire world. The use of interchangeable parts, the feasibility

of which was demonstrated by the Cadillac Motor Car Company

in 1908, was instrumental in making mass production possible.

The British phase of the Industrial Revolution saw the application

of division of labor, the first principle of industrialization, to capitalist directed

manufacturing processes. Centralized power sources were

connected through shafts, pulleys, and belts to machines housed in

factories. Even after these dramatic changes, the British preferred to

produce unique, handcrafted products formed one step at a time using

general-purpose machine tools. Seldom did they make separate components

to be assembled into standardized products.

Stories about American products that were assembled from fully

interchangeable parts began to reach Great Britain. In 1851, the British

public saw a few of these products on display at an exhibition in

London’s Crystal Palace. In 1854, they were informed by one of their

own investigative commissions that American manufacturers were

Stories about American products that were assembled from fully

interchangeable parts began to reach Great Britain. In 1851, the British

public saw a few of these products on display at an exhibition in

London’s Crystal Palace. In 1854, they were informed by one of their

own investigative commissions that American manufacturers were

building military weapons and a number of consumer products

with separately made parts that could be easily assembled, with little

filing and fitting, by semiskilled workers.

English industrialists had probably heard as much as they ever

wanted to about this so-called “American system of manufacturing”

by the first decade of the twentieth century, when word came

that American companies were building automobiles with parts

manufactured so precisely that they were interchangeable.





The Cadillac



During the fall of 1907, Frederick Bennett, an Englishman who

served as the British agent for the Cadillac Motor Car Company, paid

a visit to the company’s Detroit, Michigan, factory and was amazed

at what he saw. He later described the assembling of the relatively inexpensive

Cadillac vehicles as a demonstration of the beauty and

practicality of precision. He was convinced that if his countrymen

could see what he had seen they would also be impressed.

Most automobile builders at the time claimed that their vehicles

were built with handcrafted quality, yet at the same time they advertised

that they could supply repair parts that would fit perfectly.

In actuality, machining and filing were almost always required

when parts were replaced, and only shops with proper equipment

could do the job.

Upon his return to London, Bennett convinced the Royal Automobile

Club to sponsor a test of the precision of automobile parts. A

standardization test was set to begin on February 29, 1908, and all of

the companies then selling automobiles were invited to participate.

Only the company that Bennett represented, Cadillac, was willing

to enter the contest.

Three one-cylinder Cadillacs, each painted a different color, were

taken from stock at the company’s warehouse in London to a garage

near the Brooklands race track. The cars were first driven around

the track ten times to prove that they were operable. British mechanics

then dismantled the vehicles, placing their parts in piles in the

center of the garage, making sure that there was no way of identifying

from which car each internal piece came. Then, as a further test,

eighty-nine randomly selected parts were removed from the piles

and replaced with new ones straight from Cadillac’s storeroom in

London. The mechanics then proceeded to reassemble the automobiles,

using only screwdrivers and wrenches.

After the reconstruction, which took two weeks, the cars were

driven from the garage. They were a motley looking trio, with fenders,

doors, hoods, and wheels of mixed colors. All three were then

driven five hundred miles around the Brooklands track. The British

were amazed. Cadillac was awarded the club’s prestigious Dewar

Trophy, considered in the young automobile industry to be almost

the equivalent of a Nobel Prize. A number of European and American

automobile manufacturers began to consider the promise of interchangeable

parts and the assembly line system.





Henry M. Leland



Cadillac’s precision-built automobiles were the result of a lifetime

of experience of Henry M. Leland, an American engineer.

Known in Detroit at the turn of the century as a master of precision,

Leland became the primary connection between a series of nineteenth

century attempts to make interchangeable parts and the

large-scale use of precision parts in mass production manufacturing

during the twentieth century.

The first American use of truly interchangeable parts had occurred

in the military, nearly three-quarters of a century before the

test at Brooklands. Thomas Jefferson had written from France about

a demonstration of uniform parts for musket locks in 1785. A few

years later, Eli Whitney attempted to make muskets for the American

military by producing separate parts for assembly using specialized

machines. He was never able to produce the precision necessary

for truly interchangeable parts, but he promoted the idea

intensely. It was in 1822 at the Harpers Ferry Armory in Virginia,

and then a few years later at the Springfield Armory in Massachusetts,

that the necessary accuracy in machining was finally achieved

on a relatively large scale.

Leland began his career at the Springfield Armory in 1863, at the

age of nineteen. He worked as a tool builder during the Civil War

years and soon became an advocate of precision manufacturing. In

1890, Leland moved to Detroit, where he began a firm, Leland &

Faulconer, that would become internationally known for precision

machining. His company did well supplying parts to the bicycle industry

and internal combustion engines and transmissions to early

automobile makers. In 1899, Leland & Faulconer became the primary

supplier of engines to the first of the major automobile producers,

the Olds Motor Works.

In 1902, the directors of another Detroit firm, the Henry Ford

Company, found themselves in a desperate situation. Henry Ford,

the company founder and chief engineer, had resigned after a disagreement

with the firm’s key owner,William Murphy. Leland was

asked to take over the reorganization of the company. Because it

could no longer use Ford’s name, the business was renamed in

memory of the French explorer who had founded Detroit two hundred

years earlier, Antoine de la Mothe Cadillac.

Leland was appointed president of the Cadillac Motor Car Company.

The company, under his influence, soon became known for its

precision manufacturing. He disciplined its suppliers, rejecting anything

that did not meet his specifications, and insisted on precision

machining for all parts. By 1906, Cadillac was outselling all of its

competitors, including Oldsmobile and Ford’s new venture, the

Ford Motor Company. After the Brooklands demonstration in 1908,

Cadillac became recognized worldwide for quality and interchangeability

at a reasonable price.





Impact



The Brooklands demonstration went a long way in proving that

mass-produced goods could be durable and of relatively high quality.

It showed that standardized products, although often less costly

to make, were not necessarily cheap substitutes for handcrafted and

painstakingly fitted products. It also demonstrated that, through

the use of interchangeable parts, the job of repairing such complex

machines as automobiles could be made comparatively simple,

moving maintenance and repair work from the well-equipped machine

shop to the neighborhood garage or even to the home.

Because of the international publicity Cadillac received, Leland’s

methods began to be emulated by others in the automobile industry.

His precision manufacturing, as his daughter-in-law would later

write in his biography, “laid the foundation for the future American

[automobile] industry.” The successes of automobile manufacturers

quickly led to the introduction of mass production methods, and

strategies designed to promote their necessary corollary mass consumption,

in many other American businesses.

In 1909, Cadillac was acquired by William Crapo Durant as the

flagship company of his new holding company, which he labeled

General Motors. Leland continued to improve his production methods,

while also influencing his colleagues in the other General Motors

companies to implement many of his techniques. By the mid-

1920’s, General Motors had become the world’s largest manufacturer

of automobiles. Much of its success resulted from extensions

of Leland’s ideas. The company began offering a number of brand

name vehicles in a variety of price ranges for marketing purposes,

while still keeping the costs of production down by including in

each design a large number of commonly used, highly standardized

components.

Henry Leland resigned from Cadillac during World War I after

trying to convince Durant that General Motors should play an important

part in the war effort by contracting to build Liberty aircraft

engines for the military. He formed his own firm, named after his favorite

president, Abraham Lincoln, and went on to build about four

thousand aircraft engines in 1917 and 1918. In 1919, ready to make

automobiles again, Leland converted the Lincoln Motor Company

into a car manufacturer. Again he influenced the industry by setting

high standards for precision, but in 1921 an economic recession

forced his new venture into receivership. Ironically, Lincoln was

purchased at auction by Henry Ford. Leland retired, his name overshadowed

by those of individuals to whom he had taught the importance

of precision and interchangeable parts. Ford, as one example,

went on to become one of America’s industrial legends by

applying the standardized parts concept.





Ford and the Assembly Line



In 1913, Henry Ford, relying on the ease of fit made possible

through the use of machined and stamped interchangeable parts,

introduced the moving assembly line to the automobile industry.

He had begun production of the Model T in 1908 using stationary

assembly methods, bringing parts to assemblers. After having learned

how to increase component production significantly, through experi-

ments with interchangeable parts and moving assembly methods in

the magneto department, he began to apply this same concept to final

assembly. In the spring of 1913, Ford workers began dragging car

frames past stockpiles of parts for assembly. Soon a power source

was attached to the cars through a chain drive, and the vehicles

were pulled past the stockpiles at a constant rate.

From this time on, the pace of tasks performed by assemblers

would be controlled by the rhythm of the moving line. As demand

for the Model T increased, the number of employees along the line

was increased and the jobs were broken into smaller and simpler

tasks. With stationary assembly methods, the time required to assemble

a Model T had averaged twelve and one-half person-hours.

Dragging the chassis to the parts cut the time to six hours per vehicle,

and the power-driven, constant-rate line produced a Model T

with only ninety-three minutes of labor time. Because of these

amazing increases in productivity, Ford was able to lower the selling

price of the basic model from $900 in 1910 to $260 in 1925. He

had revolutionized automobile manufacturing: The average family

could now afford an automobile.

Soon the average family would also be able to afford many of the

other new products they had seen in magazines and newspapers.

At the turn of the century, there were many new household appliances,

farm machines, ready-made fashions, and prepackaged food

products on the market, but only the wealthier class could afford

most of these items. Major consumer goods retailers such as Sears,

Roebuck and Company, Montgomery Ward, and the Great Atlantic

and Pacific Tea Company were anxious to find lower-priced versions

of these products to sell to a growing middle-class constituency.

The methods of mass production that Henry Ford had popularized

seemed to carry promise for these products as well. During

the 1920’s, by working with such key manufacturers as Whirlpool,

Hoover, General Electric, and Westinghouse, these large distributors

helped introduce mass production methods into a large number

of consumer product industries. They changed class markets

into mass markets.

The movement toward precision also led to the birth of a separate

industry based on the manufacture of machine tools. A general

purpose lathe, milling machine, or grinder could be used for a num-

ber of operations, but mass production industries called for narrow purpose

machines designed for high-speed use in performing one

specialized step in the production process. Many more machines

were now required, one at each step in the production process. Each

machine had to be simpler to operate, with more automatic features,

because of an increased dependence on unskilled workers. The machine

tool industry became the foundation of modern production.

The miracle of mass production that followed, in products as

diverse as airplanes, communication systems, and hamburgers,

would not have been possible without the precision insisted upon

by Henry Leland in the first decade of the twentieth century. It

would not have come about without the lessons learned by Henry

Ford in the use of specialized machines and assembly methods, and

it would not have occurred without the growth of the machine tool

industry. Cadillac’s demonstration at Brooklands in 1908 proved

the practicality of precision manufacturing and interchangeable

parts to the world. It inspired American manufacturers to continue

to develop these ideas; it convinced Europeans that such production

was possible; and, for better or for worse, it played a major part

in changing the world.







Henry Martyn Leland





Henry Martyn Leland (1843-1932) is the unsung giant of

early automobile manufacturers, launching two of the bestknown

American car companies, Cadillac and Lincoln, and influenced

the success of General Motors, as well as introducing

the use of interchangeable parts. Had he allowed a model to be

named after him, as did Henry Ford and Ransom Olds, he

might have become a household name too, but he refused any

such suggestion.

Leland worked in factories during his youth. During the

CivilWar he honed his skills as a machinist at the U.S. Armory

in Springfield, Massachusetts, helping build rifles with interchangeable

parts. After the war, he learned how to machine

parts to within one-thousandth of an inch, fabricated the first

mechanical barber’s clippers, and refined the workings of air

brakes for locomotives.

This was all warm-up. In 1890 he moved to Detroit and

opened his own business, Leland and Faulconer Manufacturing

Company, specializing in automobile engines. The 10.25-horsepower

engine he built for Olds in 1901 was rejected, but the single-

cylinder (“one-lunger”) design that powered the first Cadillacs

set him on the high road in the automotive industry. More

innovations followed. He developed the electric starter, electric

lights, and dimmable headlights. During World War I he built

airplane engines for the U.S. government, and afterward converted

the design for use in his new creation, the Lincoln.

Throughout, he demanded precision from himself and those

working for him. Once, for example, he complained to Alfred P.

Sloan that a lot of ball bearings that Sloan had sold him varied

from the required engineering tolerances and showed Sloan a

few misshapen bearings to prove the claim. “Even though you

make thousands,” Leland admonished Sloan, “the first and last

should be precisely the same.” Sloan took the lesson very seriously.

When he later led General Motors to the top of the industry,

he credited Leland with teaching him what mass production

was all about.



See also: CAD/CAM ; Assembly line ; Internal combustion engine .