Based on a recent question from a reader, we looked a bit into using elements from expired patents on print-on-demand designs. As usual with intellectual property, it’s a murky area. Here’s one take from Quora:
Patent attorneys usually contract out drafting, which would make the copyright in the drawings the property of the drafter, not the inventor. Once the drafter completes the drawings, the attorney usually provides a numbering markup. So, now the attorney and drafter are co-authors. Unless, they are both employees of the inventor, this is not a work made for hire.
To have subject matter jurisdiction for a copyright lawsuit both the attorney and the drafter need to get to file a copyright application, which is then granted. At that point, they can send out a letter asking the copyist to stop. Given all that inertia and that statutory damages are unavailable unless the copyright filing is made shortly after the drawings were published, these lawsuits are unlikely. In fact, I was only able to find one and the copyright issue never surfaced because of personal jurisdiction problems Rozenblat v. Sandia Corp. 69 USPQ2d 1474 (7th Cir 2003).
This is from the questions Is it legal to sell posters of drawings of expired patents? on Quora. This certainly isn’t meant as legal advice and you should always do your own research. Also, platforms like Merch by Amazon have their own rules regarding what is allowed so the legal issues may be moot anyway.