Marquardt Butterfly switches

codemonkeymike · 21 Mar 2017, 20:09

Just got them in, more pictures to come. Along with some measurements

Daniel Beardsmore · 21 Mar 2017, 23:11

Does your double-action switch work? Good to see that you did get a normal switch out of it.

codemonkeymike · 21 Mar 2017, 23:50

Yes it does, it is quite strange in fact I thought it was just a reduced travel switch and the double action part was frictionless or maybe when it touched the bottom but if you apply a massive force at the bottom of the movement of the slider there will be the second click. It must be a tiny metal button switch with a huge force to get it actuated. The lock and unlock switches (the grey ones) are quite fun to play around with. I will be making a video of them and taking them apart hopefully without breaking them soon.

orihalcon · 22 Mar 2017, 00:18

Guessing that band aid is covering a keyboard related injury? Are those new old stock?

Daniel Beardsmore · 22 Mar 2017, 00:41

NOS yes. You miserable git, you got the working one :P Now I definitely need to see what part(s) is/are missing from mine.

codemonkeymike · 22 Mar 2017, 16:05

You would be the second Brit to call me a miserable git

. Are you sure it's missing? I had to push insanely hard to get the second action to work. Also it could be intentional for some reason.

No not a keyboard related injury, a butcher's knife related injury. Heaved my pointer in twain.

Daniel Beardsmore · 22 Mar 2017, 18:55

You may be right — I'll give it a try at some point. Stage two is meant to be insanely heavy.

Harshmallow · 22 Mar 2017, 19:48

Someone enlighten me as I think my eyes are playing tricks on me - are those three switches in one block? That's pretty neat looking.

seebart · 22 Mar 2017, 20:22

Harshmallow wrote: Someone enlighten me as I think my eyes are playing tricks on me - are those three switches in one block? That's pretty neat looking.

Yes, here is another example of switch rows in my old Key Tronic FF:

keyboards-f2/key-tronic-corp-serial-no- ... y%20tronic

: IMGP0343.JPG (949.95 KiB) Viewed 3964 times

Daniel Beardsmore · 22 Mar 2017, 22:35

codemonkeymike wrote: Are you sure it's missing? I had to push insanely hard to get the second action to work. Also it could be intentional for some reason.

You are indeed correct: my switch is complete and fully functional. I didn't even have to press that hard, either — for some reason I never pressed it hard enough before, which is weird, as I thought I had.

I won't add these figures to the wiki as they're all over the place, but very roughly:

2.35–2.5 mm, actuation point stage 1
2.9–3.1 mm, bottom out stage 1
4 mm, actuation point stage 2
4.1 mm, full travel
3.6 mm, release point stage 2

I didn't get the stage 1 release point. In reality, the distance between stage 2 actuation and full travel is more than 0.1 mm — maybe more like 0.5 mm, but it's impossible to get any kind of accurate measurement with a calliper thumbwheel while holding it all. Also, for switch travel, I need left-handed callipers, so that with my right thumb on the wheel, the device still faces me. To operate the tail, the whole thing faces backwards and I can't watch the readout.

In fact, here's some, but they're sold out and they don't have the thumbwheel needed for testing travel:

http://www.machine-dro.co.uk/left-hande ... 0mm-6.html

Sadly Jacob doesn't want to measure double action as the force level is too close to the limit of his load cell, although these feel nowhere near as awful as Mitsumi, that feels like you could support a family car on it.

It could be read by hand using mounted calipers though.

What's curious though is that the second stage is also snap action with hysteresis; as before, the drop in resistance is instantaneous and you can't hold the switch at an intermediate resistance level.

It's a nice switch.

Harshmallow wrote: Someone enlighten me as I think my eyes are playing tricks on me - are those three switches in one block? That's pretty neat looking.

Marquardt Butterfly is only known from typewriters, hence all the adaptations for typewriter use. This includes double action (the white switch; standard behaviour on electric typewriters) and mechanical shift lock (the grey switch), where pressing either shift key releases shift lock. The single key grey module has a ram that drives a release rod that connects each shift key to shift lock. Shift lock itself is inside that special three-key module — there are no sufficiently clear photos to see what's inside it, but it should have a latching mechanism as well as an releaser fed from the shift keys.

It's nothing to do with seebart's module different — for some reason, some companies found it easier to manufacturer keys in blocks, including Maxi Switch and Key Tronic. It was also used by Hi-Tek and Stackpole for peripheral keys on keyboards that used switch grids, but both companies did make single-key modules too.

Mechanical shift lock itself was also made by Cherry and others, and double action is confirmed from Cherry (M9), Alps (plate spring?), Mitsumi (Type 1 standard) and likely others.

rsbseb · 30 Mar 2017, 03:10

So are these switches intended to be used as a combination shift/caps lock key? If so that would be an interesting proposition on a compact keyboard.

Daniel Beardsmore · 30 Mar 2017, 09:13

Shift Lock and Shift are separate. Pressing Shift will release Shift Lock mechanically (using rods/levers). There is no Caps Lock: that was a later invention just on electronic systems.

purdobol · 29 Nov 2017, 14:29

There's also module with all grey switches, where every key works like Shift Lock. So only one can be active at a time. Same casing.

codemonkeymike · 29 Nov 2017, 16:39

purdobol wrote: There's also module with all grey switches, where every key works like Shift Lock. So only one can be active at a time. Same casing.

I was able to pickup an Olympia typewriter with Marquardt switches in it, so I'll have to check to see if the shift lock is of that type.

codemonkeymike · 29 Nov 2017, 16:54

Ok I took some quick and dirty pictures now because I am a bit busy but want to get the information out now.

Grey single pole, is lock/unlock switch
Grey multi pole, is lock and unlock pair
White single pole, is double action
Black on multi pole, is single action
Black single pole, is single action

purdobol · 29 Nov 2017, 17:18

Yep everything checks out. Some models have the module I'm talking about instead of those sliders on the right side (1, 1.5, 2, 10, 12, 15).

codemonkeymike · 29 Nov 2017, 17:58

purdobol wrote: Yep everything checks out. Some models have the module I'm talking about instead of those sliders on the right side (1, 1.5, 2, 10, 12, 15).
Spoiler:

I am curious to know what the mechanism is like to have a 3 way latch switch. That is some engineering effort there.

Also is your Olympia working? Mine seems to not be able to move the daisy wheel head. I think it may be a broken gear or belt.

purdobol · 29 Nov 2017, 18:33

Didn't even try to power on the first one. It was in bad shape anyway so just salvaged the keyboard.
This one from the photo arrived today and it seems to be working fine.

purdobol · 30 Nov 2017, 09:06

codemonkeymike wrote: I am curious to know what the mechanism is like to have a 3 way latch switch. That is some engineering effort there.

Turns out it's quite simple. There's plastic plate on the right side with little spring and cut out notches. Sliders have little bumps that fit those notches. When button is pressed this plastic part slides down releasing previously latched button and comes back up grabbing the one being pressed, and holds it. Third button from the top (default) has no contact plate or the metal "butterfly" plate spring. Just the central terminal and spring.

Shift lock module probably works the same way. Plastic plate connected to metal rod, slides down (releasing lock key).