I would like to know how is the status of patent number US 4396600? I read that this patent was reexamined in 1986 and I wonder why this patent was canceled since I didn't see any justification writing inside.

What I mean when the examiner said that the clains 1-23 are cancelled? Is it represent that all the patent was cancelled?

  • This case is before they started putting the image file wrappers on line. You would need to order (and pay for) the wrapper for the case. Also it is long, long since expired. – George White Mar 14 '13 at 21:47

A direct answer regarding the status is that is long expired.

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  • Thank you for answering my question. Which was the year the patent US 4396600 expired? How can I do to pay for the information about the cancel? How can I get more information about the payment(value)? – Leandro Scapin Mar 18 '13 at 11:30
  • For your future posting, you posted that follow-on question as an answer. It would have been better as a comment. If a reexam was issued canceling all claims on 2/11/86 that would make it inoperative then. The application data shows: Status: Patent Expired Due to NonPayment of Maintenance Fees Under 37 CFR 1.362 Status Date: 08-02-1987 – George White Mar 18 '13 at 20:06

Filed on December 18, 1980, U.S. Patent 4,396,600 issued on August 2, 1983 with a term ending in 2000. The PTO database states that the patent expired earlier due to non-payment of maintenance fees.

In 1984, a third-party filed a Request for Reexamination.

As a result of re-examination, on February 11, 1986, a certificate issued canceling claims 1-23 (all claims). This could explain why the maintenance fee shows up as unpaid.

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