Is the patent us4690821 still valid and in force?

Question

Is the patent us4690821 still in force and valid?

Possible duplicate of Is this patent valid? Granted? Which countries does it cover? Are there family members? — , May 04 '17 at 17:44
I haven't looked it up yet because you didn't add a link in your question. However a patent with a number in the 4 millions is very old and certainly expired. — Eric S, May 05 '17 at 00:08

score 1 · Answer 1 · edited May 05 '17 at 07:04

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Because this patent issued before 1995, the expiration date should be 17 years from the grant date of 9-01-1987 or 20 years from the earliest filing date, whichever is longer. For patents that issue after 1995, it is generally 20 years from the priority date.

edited May 05 '17 at 07:04

ASHU VERMA

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answered May 05 '17 at 02:10

Eric S

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@ASHUVERMA Thanks for the edit. This particular patent is so much earlier than 1995 that I was sure it would be 17 years from grant date although your edit is more generally correct. – Eric S May 05 '17 at 16:15

Is the patent us4690821 still valid and in force?

1 Answers1