National Presto Indus., Inc. v. West Bend Co.

National Presto Industries, Inc. (Presto) (plaintiff) developed a vegetable spiralizer in April 1991 and applied for a patent. Presto told West Bend Company (defendant), which was developing a similar product, that the patent application was pending. West Bend rushed production of its own spiralizer and released it for sale in September 1991. After Presto was granted the patent in February 1992, Presto sued West Bend in federal court for induced patent infringement. Presto claimed that West Bend’s pre-patent spiralizer sales induced customers to infringe the patent by using the spiralizers after the patent issued. West Bend filed a motion for summary judgment, seeking a ruling that Presto’s patent was invalid. West Bend only asserted one basis of invalidity during the case proceedings, including the extensively litigated motion for summary judgment. The district court ruled by summary judgment that the spiralizer patent was not invalid. The district court also ruled by summary judgment that Presto’s claim of induced infringement could not be sent to the jury. The district court held as a matter of law that liability for induced infringement could not be established based on conduct prior to the issuance of the patent. West Bend appealed the ruling of validity, arguing that it had not yet raised all possible grounds for invalidity. West Bend also argued that a material fact was in dispute because the parties disagreed about the interpretation of certain claim terms. However, West Bend did not explain how the meaning of those terms related to the issue of invalidity. Presto appealed the summary-judgment ruling on the induced-infringement claim, arguing that the district court improperly refused to send the issue to the jury.