Dear Bill, Tom, all, Thanks to Tom's fantastic tool and your explanation, I now understand that any set of Somsky Gears can be offset to produce an new set. I tested this with a random set from Tom's program (26-9-7-5) and I could see that its offset (25-10-6-4) is a Somsky set too. However, those two Somsky sets are not coaxial. I used some crude editing to overlay the two, see the attached figure. It is clear to see that the two are not coaxial. Tom has already provided me with a set of Somsky Gears, which can be coaxially offset into another set of Somsky Gears. However, not all sets of Somsky Gears can be coaxially offset like this. So what is the additional requirement that enables this? Is there a quick way how I can determine whether a Somsky set can be coaxially offset? Best regards, Oskar -----Original Message----- From: wrsomsky@gmail.com Sent: Friday, July 31, 2015 6:44 AM
From some thinking I've done, the answer is yes. Ignoring overlap, any set of Somsky Gears can be offset to produce an new set. You can prove it by noting that for a given ring-sun-planet, the strap-length changes by pi (one half a tooth) if you increase the ring and planet radii by one, and decrease the sun radius by one (or vice versa).
On 2015-07-21 13:12, M. Oskar van Deventer wrote:
Gentlemen,
Whiles I am still unsure whether there is agreement about Tom Rokicki's analysis that all Somsky Gears can be offset, nor can I follow that various mathematical reasonings, so I did an experiment with regular 120-degrees planetary gears. The attached sketch shows that a 26-8-10 fits as well as the 27-9-9 that it was offset from. Of course this does not prove anything, but at least it is consistent with Tom's analysis.
Oskar