"Anything that can go wrong, will go wrong" - Murphy
"Dubble check that spelIng" - Muphry
Murphy was a rocket engineer. One day their assistant plugged in a non-keyed connector upside down. It was very easy for that to go wrong.
Another time, in another place, a rocket assembly worker hammered in a keyed connector - upside down. It was harder for that to go wrong, but, uh, life finds a way.
I like collecting little ideas like this. Slightly meta-ironically I'd describe the genre as "just abstract enough to be useful nuggets of knowledge" and I have an org file full of them. The hard part is I don't know any better name for such "concepts" so I can't search for other people's lists.
Does anyone else keep a similar collect or have advice for finding more?
(For example Gurwinder sometimes posts lists like this: https://www.gurwinder.blog/p/30-useful-concepts-spring-2024 - that's what I'm talking about.)
The example is wrong:
"A simple poka-yoke example is demonstrated when a driver of the car equipped with a manual gearbox must press on the clutch pedal (a process step, therefore a poka-yoke) prior to starting an automobile."
You would typically put the car to a neutral gear before starting up the car, clutch isn't required.
Furthermore, if there was such a poka-yoke preventing start-up when the clutch isn't pressed, it would prevent the common safety procedure when a car doesn't start and is in a dangerous position, for example on rails or in the motorway. In such situations you would drive the car with the starter engine alone, putting the first gear on, release the clutch, and start the car, thus moving it forward slowly by the battery and the starter engine.
The mainstream French word for poka yoke is "détrompeur" but I prefer its obscure and vulgar vernacular "détrompe couillon" ("couillon" has no exact English equivalent, but you might know its Italian cousin "coglione").
Whichever name one prefers, hurray for simple interlocks that save the lives and limbs or tired inattentive operators. Dioxygen and nitrous oxide in surgical operating rooms using different connectors is a great example.
Reminded me of Pocoyo (English version narrated by Stephen Fry) [1]
Somebody is researching Lean (or DevOps?) :) For more interesting paradigms like this one, see: https://en.wikipedia.org/wiki/Toyota_Production_System#Commo...
The book covered a lot more ground and had some nifty illustrations.for those interested,
"Yoke" is pronounced like "yo K", not like the control wheel of an aircraft.
(Then again, seeing how nobody pronounces Pokémon as Pokémon, I guess striving for accurate pronunciation is a lost cause)
Also known as "eliminating the fail state" or "rendering invalid states unrepresentable".
Unfortunately, also very attractive to being used corruptly in the political arena (see nudge theory, newspeak). Can also be downright rejected, bypassed, or ignored. See most workers/employers views on OSHA.
This reminds me of how the diesel spout at the gas station is too big to fit into a car that takes gasoline.
In my industry, we mostly use the term to refer to mechanical features, typically keyways, that prevent connectors from being mated incorrectly.
Suppose you have a module with 50 pins worth of connectors, but because some of the signals are in different harnesses which get installed at different times, you can't just use a 50-pin connector. For this example let's say it's sensible to break it up as 20+20+10.
You wouldn't use two identical 20-pin connectors since they carry different signals. You probably do want to use the same family of connectors so they use common pins and have a common board footprint. So you get connectors which are the same except for having different keyways, and are often molded of different colors of plastic, by convention.
If you've ever been working on a vehicle and seen identical-looking connectors where one's black and one's gray, look closer. Along with a color difference, there's a notch on the housing in a different place.
This increases the number of parts that must be stocked, but the decrease in assembly errors is worth it. (And they all share the same tooling, so the manufacturing complexity isn't bad.)
Note that this isn't required if the connectors aren't candidates for mismating in the first place. If they appear in completely different places on the harness, then it's totally fine to reuse the very same connector for the amplifier speaker signals in the trunk, and the steering column (turnsignal stalks and stuff) module signals up front. This reduces parts count without increasing errors.