can i modify a patented product that is owned by another person and charge for my labor ? for example if a person wanted there crossbow modified can i charge them for the modification ? is this patent infringement ?

  • A interesting question. You aren't going to modify and resell the product right?
    – Eric S
    Jan 19, 2018 at 14:39
  • No , it is owned by another person and he wants it modified by me , i would be sending it back to him , just want to know if i can charge labor and not get sued for patent infringement .
    – burky
    Jan 19, 2018 at 15:38
  • I'm not a lawyer so I'd rather wait for one of those to answer. Just to clarify, are you in the US or some other country?
    – Eric S
    Jan 19, 2018 at 16:40
  • The good old USA .
    – burky
    Jan 19, 2018 at 18:28
  • Selling physical modified crossbows back to him or the intellectual property of the modification?
    – George White
    Jan 19, 2018 at 23:10

1 Answer 1


To infringe a patent one must make, sell, offer for sale, use or import a claimed device in the jurisdiction of the patent, without permission of the patent owner. Or induce anyone else to infringe or sell or import a customized part whose purpose is to be a component of an infringing device. If you do not do any of these things without the patent owners permission, you should be OK. If you are buying a crossbow in the U.S. that was made and sold with the patent owners' authorization, the patents of that patent owner which cover the crossbow are exhausted. That owner, or others might have other patents that cover the modification you are planning to do. The issue isn't charging money to make a modification. If the modifications were covered by someone else's patent, making them would be an infringement whether or not you charged money.

  • I agree as far as the patents on the existing crossbow go, but if the crossbow after the modification infringed a patent (which it didn't before), that would probably be a problem because then op would have made a patented device.
    – DonQuiKong
    Jan 20, 2018 at 12:23
  • The patent rights are lost at bill of sale correct ? so once the bow is purchase'd by someone they can do whatever they want to it Correct ?if answers are yes , then i can charge for the modification as the patent right's have been exhausted correct ?
    – burky
    Jan 21, 2018 at 1:02
  • @burky I would think that your arrangement doesn't constitute "make, sell, offer for sale, use or import a claimed device". However, I'm not a lawyer and you really shouldn't rely on internet sites for legal advice.
    – Eric S
    Jan 22, 2018 at 20:46
  • 2
    @EricShain - unless a so-modified crossbow infringes on some other party's patent.
    – George White
    Jan 23, 2018 at 5:26

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