I'm sure I've seen something like this before, but I can't find it now, or even find any appropriate names to call it to search for it.

I'm looking for a small momentary pushbutton switch similar to this: enter image description here

The switch is approximately 12.7mm by 6.35mm. But the ones I'm looking for can also be twisted 90 degrees to lock them in place while in the unpressed position so they can't be accidentally pushed.

The closest I've been able to find are huge ones at are used as emergency switches for machinery (push in to disconnect, twist to turn back on), but that's not quite what I'm looking for, and way too big.

Is there a special name for such a switch? Am I just imagining that they exist? Or do I just fail at searching?

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    \$\begingroup\$ What are your size constraints? \$\endgroup\$ – Jason Jul 19 '12 at 18:22
  • \$\begingroup\$ The exact ones that fit perfectly are [these](i.ebayimg.com/t/…. Don't have calipers with me at the moment, but they are approximately 127mm by 60mm. Rating of the switch is pretty much inconsequential since it runs about 5v@10mA. But anything similar would at least give me a starting point for finding the best one. \$\endgroup\$ – Grant Jul 19 '12 at 18:28
  • \$\begingroup\$ Those dimensions seem quite wrong from the picture (and rating). \$\endgroup\$ – Jason Jul 19 '12 at 19:36
  • \$\begingroup\$ The rating listed on the switch is 5A@120V AC. But in this case it doesn't really matter, since the actual load it's switching is very small. Just measured the switch with a tape measure, and it is about 1 inch from the top of the button to the bottom of the terminals, and the square body of the switch is 1/2 inch by 1/4 inch. But this one doesn't twist to lock it, which is what I want to replace it with. \$\endgroup\$ – Grant Jul 19 '12 at 19:44
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    \$\begingroup\$ @Grant - You don't call inches to cm conversion "math", do you? :-) \$\endgroup\$ – stevenvh Jul 20 '12 at 9:44

Another choice for protection against accidental push button switch actuation would be to install a finger guard over the switch. These come in a number of configurations as shown in the following links. One type that I would recommend is a metal cup that screws directly to the switch's threaded sleeve.




enter image description here

  • \$\begingroup\$ These are neat suggestions! \$\endgroup\$ – boardbite Sep 10 '12 at 15:17
  • \$\begingroup\$ This is possibly the most viable idea. Thanks. Dont know why I didnt think of it myself! \$\endgroup\$ – Grant Sep 11 '12 at 22:32
  • \$\begingroup\$ @Grant Thanks for accepting my answer. Mouser Electronics happens to have one of the G13B guard rings in stock and 124 of the G12KB if you wanted to get one to see how it looks with your push button. Here is the Mouser link to the part. mouser.com/ProductDetail/TE-Connectivity-Alcoswitch/G12KB/… \$\endgroup\$ – Michael Karas Sep 12 '12 at 7:30

It is named "Mushroom Emergency Stop Button Switch". Or just EMO button. enter image description here

  • \$\begingroup\$ I've seen those, and while cool they don't do quite what I'm looking for. I need a switch that works as a typical momentary pushbutton, but can be twisted to lock it in the off position. \$\endgroup\$ – Grant Jul 20 '12 at 14:23

Could you make a locking toggle switch work instead? These can be locked in position and are typically unlocked by pulling out on the toggle lever.

Typical example:

Locking Toggle Switch

A google search with "locking toggle switch" will turn up a lot of hits.

  • \$\begingroup\$ If they come as a momentary switch, that might work. \$\endgroup\$ – Grant Sep 9 '12 at 21:37
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    \$\begingroup\$ @Grant - C&K Switch company offers a bunch of options on their miniature toggle switches. Download the Series 7000 catalogue from here: ck-components.com/14428/toggle_11june12.pdf and look at page F-7 for the selection of the available locking actuator types. If you look at page F-4 you'll see the available choices of switch function styles that include momentary positions. \$\endgroup\$ – Michael Karas Sep 9 '12 at 23:42
  • \$\begingroup\$ Hmm...having to pull it up to unlock it isn't ideal, but better than nothing. \$\endgroup\$ – Grant Sep 10 '12 at 0:16

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