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My favourite example of an "idea behind its time" is the torque amplifier, which enabled mechanical analog computers on invention in the early 1900s. It is mad

My favourite example of an "idea behind its time" is the torque amplifier, which enabled mechanical analog computers on invention in the early 1900s. It is made of nothing more complicated than a source of rotary power, a couple drums/pulleys, and string/rope: https://en.wikipedia.org/wiki/Torque_amplifier https://en.wikipedia.org/wiki/Torque_amplifier

Gibbon1 7y ago
My favorite hard slogs are the zipper and the cotton harvester. The former took something like 30-40 years to develop and then no one wanted it. The latter took 100 years of tinkering.
- Animats 7y ago
  Zippers are hard to make. YKK in Japan is notably better than most of their competitors. Holding a tight tolerance on all those cheap teeth is hard.
  - Gibbon1 7y ago
    Yeah and zipper was the result of trying to design an mechanical Hook-and-eye closure. Which look nothing like a zipper. And definitely fits the articles point that somethings couldn't be made until all the supporting pieces were in place. A lot of inventions were initially hand crafted and then automation was applied to reduce cost. Think sewing pins. For zippers automation was necessary from day one. As you said hard to make. Likely cannot be made by hand.
fernly 7y ago
I don't understand why this is called an "amplifier" rather than simply "a clutch". The torque input is always the same; there is no "amplification" of the torque. The tensioned rope or spring simply applies more or less of the torque to the output, by varying the friction on the drum.
- detaro 7y ago
  That's true of pretty much any amplifier: a small signal controls how much of a large "source" is available at the output. If I had to guess, it's a) to emphasize the "signal" part and b) to make a distinction for it being used for the proportional control?
- bacon_waffle 7y ago
  The output gets more torque, just like a capstan allows a person to amplify tension on a rope. Maybe this will explain better than the wikipedia page: https://www.youtube.com/watch?v=ailf7bz9H0o https://www.youtube.com/watch?v=ailf7bz9H0o edit: spelling, grammar...
  - fernly 7y ago
    The reason I wondered, is that in years past I had serviced machines that used a "wrap spring clutch"[1] which I knew used the same principle. These are mentioned in passing in the Wpedia article on clutches[2] where it says they obey the "Capstan equation". That article[3] opens, > The capstan equation or belt friction equation, also known as Eytelwein's formula, relates the hold-force to the load-force if a flexible line is wound around a cylinder (a bollard, a winch or a capstan) So there's the generic idea, which can be viewed as a clutch or a bollard. The bollard is an "amplifier" in the same sense that a transistor is, where a small controlling voltage regulates a larger current flow. However the wrap spring clutch is on/off, not proportional, so is effectively a torque SWITCH. [1] https://www.warnerelectric.com/products/clutch-products/wrap-spring-clutches https://www.warnerelectric.com/products/clutch-products/wrap... [2] https://en.wikipedia.org/wiki/Clutch https://en.wikipedia.org/wiki/Clutch [3] https://en.wikipedia.org/wiki/Capstan_equation https://en.wikipedia.org/wiki/Capstan_equation
    - bacon_waffle 7y ago
      I think a better transistor analogy than a FET is a BJT, where both the amplified quantity and control signal are electrical current. The key difference between a clutch and torque amplifier is that, with a clutch, the output shaft power all comes from the input shaft. The torque amplifier's output shaft power mostly comes from the output drum, not the input shaft. The drums are constantly spinning, powered by some external source. https://www.youtube.com/watch?v=oNNkNc7mFJ4 https://www.youtube.com/watch?v=oNNkNc7mFJ4
SilasX 7y ago
Mine is wheeled luggage, which is very similar to products that existed in antiquity (wheelbarrow, pushcart, rickshaw). The article mentions it here: >In general, I think we should be more surprised at long gaps for inventions that have obvious, predictable impact on major industries. For this reason, the cotton gin and the flying shuttle are more compelling gaps to me than the wheeled suitcase, role-playing games, or the bicycle, which merely offer convenience or entertainment.
- ncmncm 7y ago
  Wheeled luggage waited for strong plastic.
  - krallja 7y ago
    I have formed a pet theory that wheeled luggage was dependent on the invention of roller blades.
    - analog31 7y ago
      I was going to comment on the same thing. There were no decent small wheels until Rollerblades came along with their molded polypropylene wheels and ball bearings. Skateboard wheels were a similar technology, but not as easy to mount on things. There's an album cover from the late 50s of bassist Paul Chambers rolling has bass down the sidewalk with a wheel on the bottom of his bass.
  - frosted-flakes 7y ago
    And smooth pavement.
    - iguy 7y ago
      And air travel by people too poor to have someone else cary the bag.
      - eesmith 7y ago
Animats 7y ago
That kind of torque amplifier is of limited value, and it requires fairly good materials. There's a lot of rubbing involved. Power steering uses a completely different approach. Rope has been around for millennia, but good rope is modern. Rope before manila, a 19th century development, rotted easily. (Hemp rope rots from the inside out, incidentally, so it looks fine until it breaks.) Modern rope is usually a nylon core with a polypropeline cover. Good rubber belts are post-WWII. Rubber before neoprene tended to crack, and oil made it much worse. Precisely controlled friction is a modern concept. (I restore antique Teletype machines as a hobby, and the designs from the 1920s and 1930s show these material limitations. The carriage return stop isn't rubber or some flexible material. There's a lever driving a piston in a cylinder to compress air which then comes out through a relief valve. Complex, but buildable with 1920s materials.)
- bacon_waffle 7y ago
  Part of the cleverness in that arrangement is that it has built-in negative feedback, so changes in friction between the drum and band will manifest as a change in gain or offset. Amplifiers are plenty useful even without well-controlled gain and offset. This whole discussion is mental masturbation, but I suspect if a model of a torque amplifier were sent back a few hundred years in a time machine, there wouldn't be a clear application for it. Industrial uses would evidently be fairly rare, interesting academic applications would've required calculus and control theory.

Gibbon1 7y ago

My favorite hard slogs are the zipper and the cotton harvester. The former took something like 30-40 years to develop and then no one wanted it. The latter took 100 years of tinkering.

Animats 7y ago
Zippers are hard to make. YKK in Japan is notably better than most of their competitors. Holding a tight tolerance on all those cheap teeth is hard.
- Gibbon1 7y ago
  Yeah and zipper was the result of trying to design an mechanical Hook-and-eye closure. Which look nothing like a zipper. And definitely fits the articles point that somethings couldn't be made until all the supporting pieces were in place. A lot of inventions were initially hand crafted and then automation was applied to reduce cost. Think sewing pins. For zippers automation was necessary from day one. As you said hard to make. Likely cannot be made by hand.

fernly 7y ago

I don't understand why this is called an "amplifier" rather than simply "a clutch". The torque input is always the same; there is no "amplification" of the torque. The tensioned rope or spring simply applies more or less of the torque to the output, by varying the friction on the drum.

detaro 7y ago
That's true of pretty much any amplifier: a small signal controls how much of a large "source" is available at the output. If I had to guess, it's a) to emphasize the "signal" part and b) to make a distinction for it being used for the proportional control?
bacon_waffle 7y ago
The output gets more torque, just like a capstan allows a person to amplify tension on a rope. Maybe this will explain better than the wikipedia page: https://www.youtube.com/watch?v=ailf7bz9H0o https://www.youtube.com/watch?v=ailf7bz9H0o edit: spelling, grammar...
- fernly 7y ago
  The reason I wondered, is that in years past I had serviced machines that used a "wrap spring clutch"[1] which I knew used the same principle. These are mentioned in passing in the Wpedia article on clutches[2] where it says they obey the "Capstan equation". That article[3] opens, > The capstan equation or belt friction equation, also known as Eytelwein's formula, relates the hold-force to the load-force if a flexible line is wound around a cylinder (a bollard, a winch or a capstan) So there's the generic idea, which can be viewed as a clutch or a bollard. The bollard is an "amplifier" in the same sense that a transistor is, where a small controlling voltage regulates a larger current flow. However the wrap spring clutch is on/off, not proportional, so is effectively a torque SWITCH. [1] https://www.warnerelectric.com/products/clutch-products/wrap-spring-clutches https://www.warnerelectric.com/products/clutch-products/wrap... [2] https://en.wikipedia.org/wiki/Clutch https://en.wikipedia.org/wiki/Clutch [3] https://en.wikipedia.org/wiki/Capstan_equation https://en.wikipedia.org/wiki/Capstan_equation
  - bacon_waffle 7y ago
    I think a better transistor analogy than a FET is a BJT, where both the amplified quantity and control signal are electrical current. The key difference between a clutch and torque amplifier is that, with a clutch, the output shaft power all comes from the input shaft. The torque amplifier's output shaft power mostly comes from the output drum, not the input shaft. The drums are constantly spinning, powered by some external source. https://www.youtube.com/watch?v=oNNkNc7mFJ4 https://www.youtube.com/watch?v=oNNkNc7mFJ4

SilasX 7y ago

Mine is wheeled luggage, which is very similar to products that existed in antiquity (wheelbarrow, pushcart, rickshaw). The article mentions it here: >In general, I think we should be more surprised at long gaps for inventions that have obvious, predictable impact on major industries. For this reason, the cotton gin and the flying shuttle are more compelling gaps to me than the wheeled suitcase, role-playing games, or the bicycle, which merely offer convenience or entertainment.

ncmncm 7y ago
Wheeled luggage waited for strong plastic.
- krallja 7y ago
  I have formed a pet theory that wheeled luggage was dependent on the invention of roller blades.
  - analog31 7y ago
    I was going to comment on the same thing. There were no decent small wheels until Rollerblades came along with their molded polypropylene wheels and ball bearings. Skateboard wheels were a similar technology, but not as easy to mount on things. There's an album cover from the late 50s of bassist Paul Chambers rolling has bass down the sidewalk with a wheel on the bottom of his bass.
- frosted-flakes 7y ago
  And smooth pavement.
  - iguy 7y ago
    And air travel by people too poor to have someone else cary the bag.
    - eesmith 7y ago

Animats 7y ago

That kind of torque amplifier is of limited value, and it requires fairly good materials. There's a lot of rubbing involved. Power steering uses a completely different approach. Rope has been around for millennia, but good rope is modern. Rope before manila, a 19th century development, rotted easily. (Hemp rope rots from the inside out, incidentally, so it looks fine until it breaks.) Modern rope is usually a nylon core with a polypropeline cover. Good rubber belts are post-WWII. Rubber before neoprene tended to crack, and oil made it much worse. Precisely controlled friction is a modern concept. (I restore antique Teletype machines as a hobby, and the designs from the 1920s and 1930s show these material limitations. The carriage return stop isn't rubber or some flexible material. There's a lever driving a piston in a cylinder to compress air which then comes out through a relief valve. Complex, but buildable with 1920s materials.)

bacon_waffle 7y ago
Part of the cleverness in that arrangement is that it has built-in negative feedback, so changes in friction between the drum and band will manifest as a change in gain or offset. Amplifiers are plenty useful even without well-controlled gain and offset. This whole discussion is mental masturbation, but I suspect if a model of a torque amplifier were sent back a few hundred years in a time machine, there wouldn't be a clear application for it. Industrial uses would evidently be fairly rare, interesting academic applications would've required calculus and control theory.