Patent 5,636,276 will be expiring in 2015, assuming my math is correct. The patent, which covers distributing music digitally, has been used very effectively to get royalties from many companies, recently Spotify when it came to the U.S.

My thinking is that if the patent can be used this effectively against large, successful companies, then after it expires it can be used to protect small companies and individuals.

I imagine there must be some process that a developer should follow to be sure he or she develops the product such that it can be protected if sued by owners of similar patents.

What would that process be?

Edit: I'm not looking for a step-by-step description using this patent (it's just an example), just the requirements that a court would look for when evaluating whether or not the product is properly using a public domain patent.

2 Answers 2


To add to the excellent answer above from Micah: You get a patent on the clever part of your product idea because that part is novel and non-obvious and useful. But your shipping product is almost always more than the core clever part. All of the other parts of your product are things susceptible to infringing someone else's rights. This is clear in the example of a patented improvement on an existing product. The people making the existing product may have patents on the "base" that you have a clever twist on. You can't make your really clever version without infringing their base device that was patented when it was clever 10 years ago. You can patent your domestic robot but maybe you can't make and sell one that includes a floor sweeping feature that Roomba owns.

Another scenario is some boring detail (in comparison to the cool patented core) of your shipping product might infringe something. The way the doors lock on your car that runs on water might be patented. That can be designed out, of course.

Another way to see that a patent does not give you the right to make and sell it is to consider other regulations. You can patent a baby crib that is outlawed for not meeting a safety standard.

With that major and widespread misconception out of the way I'll get back to your original question: Yes - you might try to confine your offering to only features explained in detail in an expired patent and it could provide a degree of a "safe harbor". Assuming, also, that anything relevant that was patented before its publication has also expired.

The question a court will have before it is not, do you fall within the expiired patent. That is irrelevant. The question is, do you fall under the patent you are said to have infringed.

  • 1
    So, to attempt to use public domain patents as 'safe harbor', I would have to be certain that all parts of the process are covered by the patent or applicable patents? How would a patent older than the expired 'safe harbor' patent not also be expired?
    – Paul
    Sep 15, 2013 at 0:29
  • It is the fact that it was published, not that it was patented that provides a safe harbor. Anything filed after it was published should not have been granted claims to its "teachings". It could have been a journal article rather than a patent and it would still be prior art to anything filed after its publication. How can anything filed after something else expire first? One way is via non-payment of maintenance fees, another due to a terminal disclaimer. A patent filed before this one could have had a term of 17 years from issue and could have taken a long time to issue.
    – George White
    Sep 15, 2013 at 4:54
  • So it would be wise to do something of a due diligence to determine how to use the expired patent without infringing on others?
    – Paul
    Sep 18, 2013 at 18:33
  • Yes, although many companies do not look for trouble in advance and just go a head an launch products on the theory that if they are accused of inadvertently stepping on something they can deal with it after they have the wherewithal to deal with it and maybe some patents of their own to horse trade with. Not legal advice. Not looking is very different from knowing and going a head anyway - a no no.
    – George White
    Sep 18, 2013 at 19:24

This is a great question because it elucidates a first principle of US patent law.

A patent does not grant its owner the right to build, make or sell anything.

A US patent owner has the right to prevent others from building, making or selling in the US what is described in the claims of his patent.

With regard to the subject patent 5,636,276, after it has expired, combining the elements of the claims in order to create the devices which are described in the claims of the '276 patent is placed in the public domain.

However, using the devices described by '276 does not convey any protection from other patents. For example, other patents might cover elements of the device described in '276 or might describe commercially essential improvements to the device of '276 necessary to make it practical.

George White and others on Ask Patents probably have an apt example to illustrate the general idea.

The general principle is that a patent only conveys a negative right to exclude others; when a patent expires it is placed in the public domain and that negative right is discharged.

A patent does not convey the positive right to build and sell what is described in the specification or the claims.

Any number of other negative rights (including issued patents which are currently in force but also including other laws which limit the making and selling of devices) may exist on various elements and improvements.

  • I'm not clear on this. Your stating that if the USPTO grants me a patent, and I make a product using that patent, I may be in violation of someone else's patent?
    – Paul
    Sep 14, 2013 at 21:19
  • That's correct! Sep 14, 2013 at 23:18

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