US patent 5938197 shows that it is expired due to non-payment (according to the search here: http://portal.uspto.gov/pair/PublicPair ).

This patent has several children/continuations.

Does the fact that the parent has expired due to non-payment automatically mean that the children have expired as well? They do not all show expired when I search for them, but I am not sure to what extent a continuation is connected to it's parent patent.


As an example of what is causing my confusion, here is a continuation which says it is still a patented case (rather than saying expired due to non-payment): 6,123,332

However, there is a continuation of THAT patent which is expired due to non-payment: 6,318,720

So 6,318,720 (expired) is a continuation of 6,123,332 (not expired??), which is a continuation of 5938197 (expired).

Another example: d455462 does not say it is expired. It is a division of D436635 which does not say it is expired and is a continuation of 5,938,197 which is the original one mentioned expired due to non-payment.

  • @PushpakSingh - Thanks for the help. Can you explain how you came to the conclusion that they are all expired? For example this child patent: D455,462 The only evidence I see that it might be expired is that its parent is expired.
    – JR Warren
    Commented Dec 9, 2014 at 19:59
  • US6,123,332 life is not expired but its under terminal disclaimer which will affect its expiry date. Now terminal disclaimer typically means that patent will expire with parent expiry date. In case parent patent get lapsed due to non-fee payment, child will continue till expiry date of parent patent. Hope it clears your doubt.
    – Pushpak
    Commented Dec 10, 2014 at 6:57
  • I guess you are mixing up with utility and design patents
    – Pushpak
    Commented Dec 10, 2014 at 7:00
  • @PushpakSingh - Are you saying that the patents are not connected even though the USPTO website (as well as patent D436635 itself) lists D436635 as a continuation of the original patent in question?
    – JR Warren
    Commented Dec 10, 2014 at 8:50
  • See it lists the US patent for claiming priority; Now utility patent expiry and design patent expiry are different all together please see wiki 'comparison to' section en.wikipedia.org/wiki/Design_patent
    – Pushpak
    Commented Dec 11, 2014 at 4:58

2 Answers 2


Ok first thing First all patents except US6,123,332 have expired for non-payment.

I have to dig more for your next question about parent expiry affecting child expiry with respect to maintenance fee. though i doubt that happens

NOW to main question in US patents wherein Parent child relation exist generally a terminal disclaimer is seen.

If parent patent expires due to non-payment of fee then child patent continues to term as defined in terminal disclaimer. Ref below case of more details:-

Hoffman-La Roche Inc. v. Orchid Chems. & Pharms. Ltd. (D-NJ 2011) http://www.paulhastings.com/assets/pdfs/Roche_v_Orchid.pdf

D436635 expires 23 jan 2015

D455462 expires 4 sept 2016

US6,123,332 expires without taking terminal disclaimer in account 6 Jan 2018

terminal disclaimer is not accessible in above case. There is no precedence wherein parent expiry effected child expiry so above should hold ground. On the other hand you are free to use all other patent but not '332.

disclaimer just for educational purpose, claims no liability on information provided please consult US attorney for qualified guidance.


Term of a patent is 20 years from the date on which the application for the patent was filed at the US Patent Office.

Continuing Patent Applications (continuation, CIP and divisional) claim benefit from the earlier filed non provisional application (parent application). The term of any patent issuing from a continuation, CIP or divisional application is 20 years from the filing date of the earlier filed non provisional application (parent application) for which a benefit is claimed, which means continuing applications will have shorter patent term as they expire with their parent patent.

Maintenance fee or renewal fee has to be paid for all utility patents to maintain them in force. Failure to pay such a fee on time as set forth by the US patent Law, leads to the expiry of the patent even before the term of 20 years mentioned above. In US, maintenance fee can be paid three times during the life of a patent.

It shall be noted that in US, maintenance has to be paid for all continuing applications to maintain them in force. When a parent expires due to non payment of renewal fee it may not cause all continuing applications in the chain claiming benefit from the parent or from another continuing application to expire if the maintenance fee for the continuing applications are paid on time. Similarly, any continuing application in chain may cease to have effect due to non payment of fee without causing other applications in the chain to lapse if maintenance fee for the other applications are paid on time.

The time of payment of maintenance fee for all utility patents may be found in the link provided below- http://www.uspto.gov/web/offices/pac/mpep/mpep-2500.html

Also to know more on CIP patents you may visit the link http://www.invntree.com/blogs/patent-protection-for-improvements-made-over-your-previously-filed-patent-application

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