Hi John, Would you include Nomography in such a study? After all nomograms might (just) be considered as mechanical devices
Patrick From: John Pickard Sent: Wednesday, September 07, 2016 1:14 AM To: Sundial List Subject: Using linkages to draw curves on sundials Good morning, While researching mechanisms of wire strainers used to tighten wires in fences, and trying to find the theoretical mechanical advantages of the different mechanisms, the first thing I learned was that "linkages" are the key to many of them. There's a whole branch of mechanics devoted to the theory of these things which involve a zillion combinations of pivots and links to achieve various purposes, usually to transmit motion in a specific manner. The best explanation I found was Slocum, A. (2008). Fundamentals of design. Topic 4. Linkages (http://web.mit.edu/2.75/fundamentals/FUNdaMENTALs%20Book%20pdf/FUNdaMENTALs%20Topic%204.PDF). 3.3 MB But my curiosity lead me further, to a more mathematical treatment. Unfortunately and for unknown reasons, the Jefferson Lab Library has removed the title page. Bizarre! I contacted the library and they gave me the full title etc. Svoboda, A. (1948). Computing mechanisms and linkages. MIT Radiation Laboratory Series, Volume 27. New York, McGraw-Hill. (https://www.jlab.org/ir/MITSeries/V27.PDF) (CAREFUL: 40.8 MB) Among other things, this book shows how you can use mechanical linkages of various forms to draw the curves of mathematical functions. And seeing that the curves on sundials are all defined by equations, I was wondering if anyone knows of any attempts to make a mechanical device of links and pivots specifically for generating sundial equations, and thus drawing sundials? It seems to be a feasible but complicated way of doing it, with some serious mathematics behind the linkages. I don't include sundial rulers in this, as they are not physically linked and pivotted. Similarly, I don't include CNC machining as this involves moving the tool / work using a pre-programmed series of x, y and z coordinates. And of course, 3-D printing is out. (And I still haven't figured out what sort of linkages are used in the wire strainers I'm studying!) Cheers, John John Pickard john.pick...@bigpond.com --------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial
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