Assignor Estoppel: Inventor barred from testifying for defense

RailroadPandrol v. Airboss Railway (Fed. Cir. 2005).

Pandrol sued Airboss for infringement of its RR track fastening system that resists erosion.  On summary judgment, the district court found that the patent description was “adequate to satisfy the written description requirement.”  In addition, the lower court barred one of the inventors from testifying for the defense.

Written Description: Section 112 of the patent act requires “sufficient information in the specification to show that the inventor possessed the invention at the time of that original disclosure.”  On appeal, the CAFC affirmed, finding that the claims (as construed) were sufficiently supported.

Assignor Estoppel: In addition, the CAFC reviewed the district court’s exclusion of one of the inventor’s testimony under the doctrine of assignor estoppel.  The judicial doctrine of assignor estoppel prevents the assignor of a patent from later contending that the patent is invalid.

In this case, the defendant wanted to have one of the inventors testify that the patent was invalid — a request denied by the district court. 

On appeal, the CAFC agreed that the court had correctly excluded the inventor’s testimony because it would be “unfair” to allow the inventor to testify against the patent.

File Attachment: 04-1069.pdf (83 KB)