Mechanical Calculator Keybutton pulling tool

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The_ID_of_Ed
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Mechanical Calculator Keybutton pulling tool

Postby The_ID_of_Ed » Fri May 24, 2019 12:52 am

Lately I've been working on old antique / vintage Mechanical Calculators. These fascinating old technology's use a fantastic amounts of gears, levers and springs to do their work. The most notable feature is the huge amount of buttons on the keyboards. To clean and service these machines the removal of these buttons is quite the chore with the very real possibility of running the buttons trying to pry them off any sort of readily available tool such as a screwdriver. Thus I designed a tool that is designed to pull the Key Caps off in a nice straight linear fashion with as much even support at their base as possible. The tool works quite well and is easily printed and assembled as is shown in my video.

https://youtu.be/Tr2nGsmGur8

The design files include the original FreeCAD files in case anyone would like to modify the design for other applications. The Extractor tool 3D print and FreeCAD design files are at.

https://www.thingiverse.com/thing:3649767

I've been posting my other efforts on YouTube.

https://www.youtube.com/channel/UCtBGrx ... JbA/videos
Mechanical Calculator Key Button Puller 3D printed.png
Mechanical Calculator Key Button Puller 3D printed.png (14.99 KiB) Viewed 1241 times
chrisb
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Re: Mechanical Calculator Keybutton pulling tool

Postby chrisb » Fri May 24, 2019 8:01 am

Nice puller. Is there a reason why you modeled the linear rack in two pieces?
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The_ID_of_Ed
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Re: Mechanical Calculator Keybutton pulling tool

Postby The_ID_of_Ed » Fri May 24, 2019 3:15 pm

Mostly just lazy. I'd have to mirror and fuse the models to produce a single part. Then put more attention into the screw and clearance holes for the mounting of the pull finger. Then also the part could more likely break at the formed slot joint. With the parts being septate they have a bit more flex. The last consideration is the stresses would be different between the toothed and the smooth sides of the opposing racks and would give a bit of spring into the rotating gears, in the hope that would give a bit more mesh if needed. Mostly just being lazy though.
chrisb
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Joined: Tue Mar 17, 2015 9:14 am

Re: Mechanical Calculator Keybutton pulling tool

Postby chrisb » Fri May 24, 2019 5:15 pm

Thanks for the answer. I watched the video with the tool in action. Until then I did not quite understand that it is the top plate against which the puller presses.