Suppose the Claim 1 of a patent is as follows:

An assembly comprising:


a threaded nut positioned at least partially within the housing such that the nut is fixed against rotation with respect to the housing, wherein the threaded nut is ...;

...; and


If an assembly incorporates an "unthreaded nut" rather than a "threaded nut", would that avoid infringing the patent completely irrespective of the rest of the conjunctive clauses/claims? That is, could a specific minor change avoid infringing a claim?

Similarly, could a "threaded nut" be used as long as it isn't fixed against rotation?

Any thought appreciated.

2 Answers 2


Simply put, a specific minor change MAY avoid infringement.

There's something in the United States called the doctrine of equivalents that gives patentees protection that is broader than the literal language of their claims. So a patentee may argue that what you think is a minor change is actually "equivalent" in the eyes of patent law.

I'll let you google the doctrine of equivalents, but based on your example, I'd rather argue that an unthreaded nut does NOT infringe than argue that it does.

The patentee may also argue that your nut is, in fact, threaded or that what you think is not fixed against rotation is, in fact, fixed against rotation. In other words, even though you think you're not infringing, and even if your attorney agrees you're not infringing, a determined/aggressive patentee could still allege that you are.

If that allegation is egregiously ridiculous, then the courts might eventually compensate you for the trouble, but that's a very different topic.

  • Thanks. When determining infringement, is the description of the invention in the current patent important? If the claims are worded more broadly than what the description specifies, which one takes precedence?
    – John M.
    Commented Apr 18, 2016 at 1:25
  • Generally, the claims control. But the specifics and nuances can change their meaning. Commented Apr 18, 2016 at 3:12

It depends on what you meant by unthreaded nut. If your nut has two notches that engage with a threaded element, then the patentee might argue that it is a partial thread. If your nut is, say, a snap-on nut, then you should be off the hook.

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