Timeline for Planar linkage that traces a circle from its exterior?
Current License: CC BY-SA 3.0
8 events
| when toggle format | what | by | license | comment | |
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| Feb 8, 2014 at 21:36 | comment | added | Joseph O'Rourke | @AntonPetrunin: You are right, just drawing an arc from its exterior is not that difficult or interesting; my misjudgement. But drawing a large portion, or all of a circle, still seems challenging. | |
| Feb 8, 2014 at 14:41 | history | edited | Joseph O'Rourke | CC BY-SA 3.0 |
Illustrated TMA's clever idea.
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| Feb 8, 2014 at 5:47 | comment | added | Anton Petrunin | You say "Following a subarc would also be interesting." But that is what Peaucellier linkage does if you move the fixed end of blue segment a bit from the other fixed join (the end of two green segments). [On the second picture you need to choose the hole on the right.] | |
| Feb 8, 2014 at 4:35 | answer | added | The Masked Avenger | timeline score: 2 | |
| Feb 8, 2014 at 2:16 | comment | added | Will Jagy | I think if you go back far enough in history there will be something understandable. Note that the ideal face of a lens with flat on the other side is actually a hyperboloid of revolution, at least for one fixed wavelength of light. For parabolic mirrors, one thing they are doing is making giant rotating baths of mercury, to get a perfect parabolic surface for large optical telescope. en.wikipedia.org/wiki/Liquid_mirror_telescope | |
| Feb 8, 2014 at 2:00 | comment | added | Joseph O'Rourke | @WillJagy: Cool connection, Will! With that hint I found several patents for lens polishing mechanisms, each impenetrable to me (although with limited time investment). | |
| Feb 8, 2014 at 1:31 | comment | added | Will Jagy | what comes to mind is lens polishing, the surfaces of lenses for telescopes having generally had a spherical face. | |
| Feb 8, 2014 at 1:04 | history | asked | Joseph O'Rourke | CC BY-SA 3.0 |