h a l f b a k e r yNot so much a thought experiment as a single neuron misfire.
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I like the way spiral binding works to allow notebooks and calendars to lie flat. But occasionally I'd like the ability to add a sheet in the middle of an already-filled section.
Enter: Nitinol Spiral Binding!
Simply remove the bifilar-wound spring by snapping on a 9V battery, and watch as
the binding detaches itself from the pages. Now add a sheet from the end of the sheaf, disconnect the battery, and allow the nitinol wire to cool and regain its shape, carefully rebinding the newly added sheet in place.
(A similar electrically-alterable structure may be used to form your croissants.)
Nitinol
http://en.wikipedia.org/wiki/Nitinol
Shape-memory wire [csea, Feb 23 2009]
Spiral Binding
http://www.lse.ac.u...lSpiralBinding2.gif
The type of binding to which I refer [csea, Feb 23 2009]
Bifilar Winding
http://www.answers....pic/bifilar-winding
definition [csea, Feb 23 2009]
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Cold, Nitinol stays in any form given to it; warm, it returns to the original form.
So if the original form was the open binder, you'd have to manually close it again, or vice versa.
So where does the automatic open+close come from? |
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[loonquawl], Good point. Perhaps there are two sets of wires mechanically bonded, but thermally and electrically insulated from eachother, and a switch to select "open" or "close". |
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Might depend if the force when heated exceeds the bending requirement when cold. Hence the halfbakedness. |
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It's the last sentence of P2 that throws me. There is no way a straight wire, if placed next to a sheaf of paper, is going to be able to spiral itself through the holes. I think that would require a more complicated system then simply memoryform wire. Since you can screw and unscrew spiral bindings why do we need to straighten out the wire at all? |
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[csea] posted a picture of the "spiral binding" - it is not a spiral, but looks superficially similar |
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