The second and third examples are safety lockouts [0] working as intended: Some system is locked in the off state to ensure safe access for technicians.
Especially the padlock lockout is simple and effective: As long as you have the key in your pocket, you can be sure than no one is going to turn on the meat grinder you are cleaning.
Creators of some keyboards placing a sleep button right above arrow keys didn't bother doing this.
For the power button is located next to two USB ports I use and, for whatever reason and although it's a very good PC tower, the button is ultra sensitive.
So I created a "not-molly guard" that "plugs" into the two audio jacks (which I never use and which are, also, next to the power button) and that only leaves a narrow hole and a guardrail of a few millimeters.
Printing it in black, matching the tower's lip where the power button is, and life is good. Already hit that Molly guard several times by mistake so I figured out I already saved more time than it took to design it.
As it's a small piece, it printed in a few minutes on the 3D printer.
P.S: AFAICT there's no software setting (?) to prevent the power button from doing what it does!? But who cares, I've got the Molly guard now.
[1] https://www.youtube.com/watch?v=se0F1bLfFKY
[2] https://cpc.farnell.com/rjs-electronics/rjs-k16-391-ge-65j/i...
They're recessed. Buttons come with recessed or raised actuators depending on the application. Recessed buttons prevent something bumping into the control panel from pressing the button. If you ever look at a properly designed industrial control panel, start buttons are flush or recessed and stop buttons raised.
Emergency stop buttons (E-Stop) are not only raised but feature a large "mushroom head" design to ensure they are visible and easy to press. They may have a recessed guard around them to prevent accidental actuation.
> [2] https://cpc.farnell.com/rjs-electronics/rjs-k16-391-ge-65j/i...
Side note: I grew up in a machine shop and the Comet VMC-1000 Mills we had featured a lot of the square/rectangular buttons[1]. The cycle start button has a Molly guard but is almost always missing as it's quite fragile and easily knocked off (ours were missing too.) I like the aesthetics so when I went to Japan and explored Akihibara Electric City, I found an industrial electronics vendor[2] just outside of the Akihibara Station who had a nice selection of them from Fuji Electric. I bought a bunch with 24V lamps for a PLC test stand. Another vendor is eao.
1. https://cdn.globalauctionplatform.com/auctions-2023/bsctho10...
It's in Dortmund: https://www.dasa-dortmund.de/en/
The author also has a list of his favorite tech museums: https://aresluna.org/fav-tech-museums/
