geekhack
geekhack Community => Keyboards => Topic started by: 1395985 on Tue, 03 April 2012, 13:56:42
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Inside an IBM (Lexmark manufactured) 1395985 Model M buckling spring keyboard:
[video=youtube;SuWLlbkeNfc]http://www.youtube.com/watch?v=SuWLlbkeNfc[/video]
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is the top plate on a buckling spring assembly (ie, the one that the keys attach directly to) metal or plastic?
edit: not the outer chassis, but the black plate in your video.
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is the top plate on a buckling spring assembly (ie, the one that the keys attach directly to) metal or plastic?
edit: not the outer chassis, but the black plate in your video.
The curved back plate is mild steel, perforated to accept the plastic posts from the plastic moulding, which are heat staked down to hold the steel back plate firmly in place. On top of that sits the plastic moulding into which the keys slide - this is heat staked to the back plate, and into it is moulded the barrels inside which the springs sit. At the very bottom of these barrels are the hard plastic "hammers" which are actuated when the springs buckle, causing the hammer to snap forward on their pivots, and slap against the rubber membrane, in turn causing pressure which shorts out the relevant contacts on the silvered mylar membrane sandwich underneath the rubber mat. Inbetween the back plate and the plastic moulding are the membranes and rubber sheet etc. I'm not explaining this too well, but I hope this link explains it better:
http://www.preater.com/modelm/
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i've got it, thanks!
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i've got it, thanks!
You are most welcome :-)