I have an application B that the examiner has provisionally rejected under double patenting, as the application has similarities with a prior application A that I made.

The two were submitted a month apart, and I think the loss of term for B is therefore not substantial enough to warrant spending time constructing an argument to traverse the rejection.

The examiner claims (to paraphrase) that B is like A if you read "an arrival" to be the same as "a departure". If I sign a terminal disclaimer, am I opening myself up to estoppel, or can I simply submit the terminal disclaimer with no comment, thereby not admitting that "an arrival" is the same as "a departure" (I don't think they are)?

Are there any other pitfalls associated with signing and submitting terminal disclaimers? Also, what is a "timely filed" terminal disclaimer?

  • Could you provide part of the wording of the relvant claim(s)? Just the words around arrival / departure or a similar worded example. For example, if you had an apparatus usable for detecting the arrival of an airplane and one for detecting the departure but it was otherwise the same apparatus, you would actually, at least for european right, have an overlap in the claims because that only means "usable for" but not "is used for", so it could be the same apparatus and it would be infringed even if used for checking the arrival of a car. Therefore, some context might help.
    – user18033
    Apr 19, 2018 at 14:02
  • Additionally, is the examiner saying its the same or one includes the other? I wouldn't see as many problems admitting that arrival could include departure and vice versa as saying they are the same.
    – user18033
    Apr 19, 2018 at 14:02
  • The examiner is saying that the claims of B are rejected on the ground of nonstatutory double patenting because although they're not identical, they are not patentably distinct. I've also got an Alice rejection and a 103 rejection to deal with, so it's going to be a great education. There's also some weird grammar in the office action "Although the claims at issue are not identical, they are not patentably distinct from each other because key revocation message broadly interpreted as key announcement message". Apr 19, 2018 at 15:04
  • generating, by a network connected device, a key announcement message for a first public key of a first public/private key pair; and Apr 19, 2018 at 15:04
  • generating, by a network connected device, a key revocation message for a first public/private key pair; and Apr 19, 2018 at 15:04

1 Answer 1


Clearly do not go on the record agreeing to the examiner's point of view; and much better if you explicitly state you do not agree. You probably already know this, but besides affecting the term, it also ties the ownership of the two patents together forever.

  • Thanks George. I have since read some more articles on terminal disclaimers - and as suspected there's a lot more to them than first meets the eye. I also have the "engineering instinct" to overcome, which is to agree if there's even a slight connection, whereas lawyers seem to default to disagreeing, albeit "respectfully". Apr 23, 2018 at 6:12

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