Programmable Logic Controller (PLC)

Programmable Logic Controller’s (PLC’s) are small single-purpose computers. They control machines and are common in cars. You probably own more PLC’s than any other type of computer. Today, a single-car has a myriad of PLC’s, usually networked together. PLC’s replace hard-coded wiring, automating tasks.

PLC’s often read input from analog sensors. Responding to temperature, sensing a pedal or a handle, then causing a machine to do something are typical PLC functions.

GM’s automatic transmission was the first application of a PLC. Bedford Associates won a Request for Proposal (RFP) and the lead engineer was Disk Morley.

Besides cars, PLC’s are a common and vital component of modern factories, elevators, and all manner of heavy machinery that repeats the same task.

Because PLC’s are limited in function, they are also typically extremely inexpensive.

Industrial Robot

Though understated at the time, few inventions have had as much impact as the industrial robot.

Industrial robots were invented by George Devol. A prolific innovator, Devol patented the “Unimate” – a term he coined – in 1954 to name his robot.

Robots have existed in science fiction for ages, often as machines in human form. The Wizard of Oz movie had the Tinman dancing and singing fifteen years before Devol’s real robot, and the movie is based on a book published in 1900.

Devol’s Unimate neither sung nor danced. It wasn’t especially attractive and, unlike the Tinman, didn’t want a heart. More to the point, factory owners did not want a worker with a heart, or a brain, or the need for sleep, breaks, vacations, weekends, health insurance or a pension. Unimate could grip, weld, tool, and spray.

Previously to the Unimate, Devol had built and sold several innovations including the self-opening door. Dee Horton and Lew Hewitt tried to steal credit despite that their door was launched two decades after Devol’s. The experience of dealing with IP thieves made Devol acutely aware of slimy business practices.

There was no prior art to Devol’s robot. Despite a long history in science fiction, nobody had submitted a patent for anything like it before.

In 1960, Devol sold the first robot to General Motors to lift and stack hot pipes. Chrysler, Ford, and Fiat followed.

Devol went on to spend the rest of his life improving industrial robots. Engelberger worked with Devol. Unimate thrived until the early 1980s when they failed to transition from hydraulic to electric motors.

Computer Numerical Control (CNC) Machine

Computer Numerical Control (CNC) machines create identical interchangeable parts. They simplify manufacturing and reduce the risk of human error producing parts.

Starting in 1949, John Parsons worked with Frank Stulen at Gordon S. Brown’s Servomechanisms Laboratory at MIT to develop a system where punch cards controlled a machining tool, called Numerical Control (NC).

This evolved into Computer Numerical Control (CNC) as computers evolved. Developing CNC was extremely expensive. CNC development ran wildly over budget, so much that Parsons lost his job. Eventually, patent royalties justified rehiring him.

Parsons originally created CNC, using IBM accounting computers, to build helicopter blades for the then new Sikorsky helicopter company.

Technologists often refer to the development of CNC as the beginning of the “second industrial revolution.”

RO: Why did it take so long between licensing the patent and the widespread use of NC?

Parsons: The slow progress of computer development was part of the problem. In addition, the people who were trying to sell the idea didn’t really know manufacturing—they were computer people. The NC concept was so strange to manufacturers and so slow to catch on, that the US Army itself finally had to build 120 NC machines and lease them to various manufacturers to begin popularizing its use.

Automobile Assembly Line

Assembly lines leverage standardized parts to break auto assembly into discrete components, each that can be done by a small number of people (often just one). Standardized parts evolved into standardized jobs.

Ransom Olds, inspired by a musket factory that used standardized parts with workers each focused on one part, created the first auto assembly line. Olds, the founder of Oldsmobile, did well. His cars sold for $150 less than Ford’s (pre-Model T). However, investors, determined to build pricier cars, pushed him out of his company.

The “disassembly” lines at Chicago slaughterhouses served as inspiration for Ford employee William Klann. One person repeatedly performs an individual task, butchering animals in stations. However, the single station factory is an old concept, arguably dating back to at least Arkwright-era factories.

Ford, via Klann, adopted the auto assembly line. He is generally (and wrongly) credited with the innovation of the auto assembly line.

Synthetic Ammonia

Fritz Haber arguably saved and killed more people than any other single person in history.

Synthetic ammonia vastly lowered the cost of making fertilizer, explosives, and other chemicals.

The process to create synthetic ammonia was a concurrent invention. That is, two scientists came up with it at the same time independently of one another.

Because it allows for inexpensive fertilizer, the Haber-Bosch is responsible for approximately half the food grown in the world today. Fritz Haber, who both invented and also commercialized the process, saved billions of lives.

However, there is a darker history. Haber was a German Jew, a key German chemist developing chemical weapons for Germany in WWI. He oversaw their first use at the Second Battle of Ypres, where approximately 67,000 allied troops were killed in one gassing. His first wife committed suicide after learning how many people he helped kill.

Later, the institute he founded invented Zyklon A. Nazis used a successor chemical, Zyklon B, to murder millions in death camps including many members of Haber’s family. This caused his second wife to leave him, with the marriage ending in divorce.

Both, like Haber, converted from Judaism to Christianity though the Nazis did not care and banned Haber from his lab. He escaped Nazi Germany but died soon after the Nazi’s ascent to power in Basel, Switzerland.

Haber won the 1919 Nobel Prize in Chemistry but died a miserable man.

Circular Saw


Tabitha Babbit

In 1777, Samuel Miller patented the first circular saw. However, the wind-powered saw did not have enough power to be of practical use.

In 1813, Tabitha Babbit, a Shaker, invented the circular.

Her insight was that sawing back and forth wasted half the motion of a saw. In response, she created a circular saw. To power the circular saw, she attached a blade to a water wheel. Today’s circular saws are typically smaller, and powered by electricity, but not altogether different.

Due to her Shaker religion, she did not believe in patents, believing her innovations to be for the good of everybody.

Men far outnumber women as noted innovators, especially during this timeframe. Babbit’s background as a Shaker, a religious community that often put women in leadership, likely contributed to her idea being adopted.

Shakers are a group that split off from Quakers to form a similar religion. During worship, they do a dance, the Shaker Dance.

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The Shaker Dance

Among other things, Shakers believed that sex was the original sin and did away with it. To prevent temptation, men and women lived separately. Marriage and sex were forbidden. Besides leadership roles, which typically went to women, jobs were assigned based on traditional sex roles. This makes it all the more amazing that Babbit would watch men sawing wood and notice the wasted energy or a straight-edge blade.

Predictably, the prohibition on sex and marriage became a long-term problem. No sex meant no offspring. Since children typically take their parent’s religion, there are very few Shakers today. As of 2019, there are only two living Shakers left in the world.

Babbit didn’t stop inventing with the saw. She also created an improvement on the spinning wheel, an improved method to manufacture wooden teeth, and — along with others — a type of nail called a “cut nail.”

Shaker Dance

Programmable Machine (Jacquard Loom)

The Jacquard Loom is a seminal invention in the history of modern computers. Automation technology existed long before the loom but the automation was simple repetition. For example, pull the loom up, push a thread through, pull the loom down, and push another thread through then repeat. Different color threads might be used on different spools to create basic stripes but the looms were limited in their inability to actively change.

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Jacquard Loom with punch cards

The Jacquard Loom is inherently different. It used a series of punchcards to control the threads. Each card pushed through a different pattern. When combined, the output fabric left elaborate patterns.

The Jacquard Loom established that the steps an automation machine took need not be a simple repetition but might, instead, but a long and complex series of instructions.

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Jacquard Loom doing its thing

Jacquard’s programmable loom wove different patterns, just like modern computer chips run different instructions in a program. A quick clarification: even though you do not see it, your computer has a central brain that performs instructions depending upon the data set to it. It is like an electronic loom except it outputs electrical signals rather than controlling the threads of a loom. Where a loom might have a few hundred threads, most computer chips have the electronic equivalent of hundreds of millions or even billions.

However, the loom was not simply an interesting science experiment. It vastly decreased the price of patterned fabrics.

Napoleon granted a patent to the city of Lyon, where he lived, and awarded Jacquard a lifelong pension of 3,000 francs plus a 50 franc royalty for each loom purchased and used between 1805 and 1811. Jacquard did well but the government seems to have done better.

Early computers used punched-out cards that looked eerily similar to that used by Jacquard. Where his loom used the punched-out patterns to control a loom, the computer punch-cards controlled the flow of electricity through a computer, feeding it both programs and data to process.

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Jacquard Loom control card
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Computer punch card

Interchangeable Standardized Parts: the “American Manufacturing Method”

Standardized parts allow parts of a machine to be swapped out, enabling factories to manufacture parts without worrying about the larger machine. Interchangeable parts vastly lowered manufacturing costs.

Check out the video we created about interchangeable standardized parts:

Today, everything from cars to computers, software and even food, is interchangeable. We’re annoyed that a USB plug only works in one direction but the idea that such a plug works at all — that it fits into countless computers and makes enormous data stores accessible — is a big yawn.

Today, we take it for granted that parts can be replaced and that every part is the same. But, at the time, this was an enormous breakthrough.

Le Blanc

Messrs. Le Blanc is a Frenchman gunsmith who devised a musket with interchangeable parts and the idea in general. Gaspard Cotty describes the innovation in a multi-page footnote in his 1806 book, Memoire sur la Fabrication des armes portatives de guerre.

On a table is place a collection of random parts to create about 50 muskets. An observer picks random pieces then fits them together into a fully functioning musket. Muskets were individually handcrafted, at enormous cost, before Le Blanc’s innovation.

Interchangeable parts vastly lowering the cost of maintaining an army.

Then US Ambassador to France Thomas Jefferson witnessed Le Blanc’s demonstration and invited him to bring it to the US. Le Blanc declined, wishing to remain in France. France, concerned about job loss, declined to embrace Le Blanc’s method.

There is some speculation that the idea of standardized parts predates Le Blanc, though Cotty’s 1806 book — written in a pre-Napoleanic french dialect — shows that to be unlikely.

Specifically, Cotty notes that Le Blanc:

  • Is the first to use “hardened steel” (a process apparently in use for some time in the steel industry) to produce the lock of a firearm; Le Blanc created this technique in 1777.
  • Highlights the pros and cons of interchangeable standardized parts for muskets.
  • Specifically details Le Blank presenting 50 or 60 rifles to Mr. de Gribeauval, “inspecteur general de l’artillerie,” the inspector general of the French artillery, in 1789 before the French Revolution.
  • Le Blanc then had his men take the rifles apart, mix up the parts, and put them back together. However, there were enough defects that de Gribeauval decided to rely on “old” (their word) manufacturing methods.
  • de Gribeauval was also concerned with complaints from soldiers about the standardized parts muskets and with the effect on jobs.

There was some speculation that Jefferson’s recounting of the French demonstration was an urban legend. Jefferson mentions the demonstration in a 1789 letter to Henry Knox but there is no other mention despite the enormity of the innovation. However, Cotty’s account makes the idea that Jefferson fabricated the idea to gain traction extremely unlikely.

Eli Whitney

Jefferson eventually returned to the US and brought the idea of standardized parts to Eli Whitney, inventor of the cotton gin. Jefferson, in his earlier role as Secretary of State, failed to process Whitney’s cotton gin patent in a timely manner. In all fairness, Jefferson openly did not like patents and was slow to process virtually all patent applications, not just Whitney’s. For example, he eventually granted four separate people a shared patent for the steamboat despite that two of the applicants didn’t have working boats. Jefferson was openly hostile to patents.

Due in part to the lack of patent protection knockoff cotton gin’s thrived and Whitney made no profit. Feeling a sense of guilt, Jefferson brought Whitney the idea for a musket based on interchangeable parts.

Jefferson worked with Whitney to repeat the same demonstration as Le Blanc, mixing up a bunch of parts then assembling a musket. However, Whitney’s parts all fit together perfectly, probably because historians agree they cheated and marked parts Whitney knew were pre-fitted.

Whitney, with his well-known name and Jefferson’s help, secured a contract to build an interchangeable part musket. His factory never quite worked — he could not build the parts to tight enough tolerances — but his children, who took over the factory, eventually succeeded.

Despite that Le Blanc of France created the concept, interchangeable standardized parts became known as the American Manufacturing Method.


Later, Sam Colt thrived on interchangeable parts. Ford was also an interchangeable parts fanatic, to the point he insisted that shipping crates use the same size planks for reusability.

Hydraulic Press

Before the press, shaping metal was a slow, difficult, expensive, and laborious process. The hydraulic press allows metal to be easily and inexpensively shaped. Today, the same hydraulics power a lot of modern industrial equipment.

Bramah, a farmer’s son, was an innovator who specialized in locks. He created and patented many types of locks. He also, as a digression to his primary work, invented the hydraulic press and receiving a patent in 1795.

Despite the importance of the innovation, Bramah appeared to earn his living from the lock business, not the press. 

Bramah also innovated screw-propelled ships.

Henry Maudslay worked for Bramah and was central to core innovations, including building a system that could contain the pressures of the press. However, Maudslay left after Bramah refused him a raise to open his own shop.

Maudslay perfected and commercialized Bramah’s press and also created the screw cutting lathe. Both are key innovations of the Industrial Revolution.

Automated Flour Mill

Oliver Evans’ mill vastly lowered the cost while increasing the quality of flour. These mills automated the milling of flour much like Arkwright automated the creation of fabric. The automatic mills were popular with farmers.

Evans automated mill reduced the time and increased the quality and consistency of flour. George Washington purchased one that is still in use, for demonstration purposes, today.

Evans was a prolific innovator and also created a high power steam engine (concurrently with Trevithick) and also designed the core concepts of refrigeration.

Evans had trouble enforcing his patents but, eventually, did make a living from automated mills.

Evans is also, arguably, the innovator of the grain elevator. In an odd twist ー opposite of what usually happens (where people steal and patent the ideas of others) ー Joseph Dart created a grain elevator in 1842 but credits the innovation to Evans.        

Washington’s automated Evans Mill is still operational.