Hello
I have question? How long time patent our wheel mecanum is important?
regards
from a post by Dave L in another thread:
The patent for Mecanum wheels (also known as “Swedish wheels”) goes back to the 1970s. They were developed by Bengt Ilon, an engineer for the Swedish company Mecanum AB (one paper describing some of the early Mecanum wheel history and designs can be found here http://www.araa.asn.au/acra/acra2002/Papers/Diegel-Badve-Bright-Potgieter-Tlale.pdf ).
I dont know if the patent has expired yet.
BTW, your english is much better than my polish :^)
I ask you becourse I wont sell my mecanum wheels and I don’t know I can?
I think the best answer is you need to consult a patent lawyer, to do a search and see what patents might still apply to the design you want to sell.
But maybe someone else on this forum knows off hand, when the basic patents on mecanum wheels will expire?
or, how do you search the patent libraries to find out?
The patent is for “Wheels for a course stable self propelling vehicle
movable in any desired direction…”. number pat. us 003876255 but I can’t find this number 
offis patent US
It is from 1975 and I think that patents normally expire after at most 20 years, so I would guess that it isn’t valid any more.
US Patents are good for 17 years. I’m not sure if that is from the date of application or the date of invention. In either case the mecanum patents are long expired. International patents are different. If you are in Poland, then US patents have no relevance. US Patents might be used to establish a date of invention for an international patent dispute. But they carry no weight in a different country, make all you want just do not sell them in the US. However International patents might apply. So you would have to check those out too.
Try this link: http://www.chiefdelphi.com/forums/papers.php?s=&action=single&paperid=556
That’s the patent in question, saved as a .pdf file. To see it on the USPTO site, you need a .tiff viewer.
As for being expired, it depends. It’s likely that Sweden, the U.S. and Poland are all signatories to the PCT, so it is possible that an application was made to extend the U.S. patent (and/or Swedish patent, if it exists) worldwide. Though that patent would probably have expired, there may be other patents derived from it that are still in force.