In Lismont v Alexander Binzel Corp (Slip Op 2014-1846, Fed Cir, February 16 2016), a Federal Circuit panel held that a rebuttable presumption of laches attaches to an inventorship claim when more than six years passes from the time a purported omitted inventor knew or should have known of the issuance of the relevant patent. The presumption may be rebutted if the omitted inventor provides evidence:

  • showing an excuse for the delay;
  • showing that the delay was reasonable; or
  • placing defence prejudice and economic prejudice genuinely in issue.


Plaintiff Hedwig Lismont sued defendant Alexander Binzel Schweisstechnik GmbH & Co KG, alleging that he should have been listed as an inventor on US Patent 4,429,406 (the '406 patent), issued in 2002. The '406 patent is generally directed to a method of manufacturing a contact tip for use in metal inert gas welding and claims priority over German Patent 197 37 934 (the DE '934 patent), filed in 1997.

Lismont asserted that following a request from Binzel, he began developing the claimed method in 1995 and reported the completed method to Binzel in 1997. However, in filing the patent applications for the DE '934 and '406 patents, Binzel did not include Lismont as a named inventor. As a result, Lismont initiated litigation in a German court in 2000, seeking a change in inventorship on the DE '934 patent. Following subsequent litigation and additional related suits, the German courts ruled that Lismont had failed to prove that he had an inventorship interest in the DE '934 patent.

On October 31 2012 – 12 years after filing the first suit in the German court – Lismont initiated US litigation in the Eastern District of Virginia District Court seeking to correct the inventorship of the '406 patent. The district court granted Binzel's motion for summary judgment and dismissed the suit as being barred by laches. Lismont appealed.


The court first addressed whether a rebuttable presumption of laches applied to Lismont's inventorship claim. Based on a statement that Lismont made to the German court, the court agreed with the district court and held that Lismont knew or should have known of the '406 patent's issuance and thus that the laches clock started to run when the '406 patent was issued. The court explained that the only relevant inquiry for the presumption of laches is whether six years has passed from knowledge of the patent's issuance to litigation, and it was undisputed that more than 10 years had passed. Therefore, the district court correctly determined that the rebuttable presumption of laches attached.

The court then addressed whether Lismont had met his burden to rebut the presumption of laches. It found that filing other foreign litigations could rebut the presumption if it put the defendant on adequate notice that the plaintiff intends to pursue its rights in the United States. However, the court held that Lismont did not meet this burden because there was no evidence that he had communicated his intent to pursue a separate inventorship claim in the United States and that "the mere initiation of patent litigation in a foreign jurisdiction and the existence of United States patents are not sufficient to notify the defendant that the plaintiff will eventually seek to assert its patent rights in the United States".

For further information on this topic please contact Christopher E Loh or Christopher J Stankus at Fitzpatrick, Cella, Harper & Scinto by telephone (+1 212 218 2100) or email ( or The Fitzpatrick, Cella, Harper & Scinto website can be accessed at

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