Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., Ltd.
United States Supreme Court
535 U.S. 722 (2002)
- Written by Angela Patrick, JD
Facts
Festo Corporation (plaintiff) owned two patents for a magnetic rodless cylinder. Both patents were initially rejected for insufficient descriptions. Festo amended both patents to include more detail, including adding a limitation that the device had two one-way sealing rings. The first patent also added that the device’s sleeve was made of magnetizable material. Festo’s patents were granted as amended, with these limitations. Shoketsu Kinzoku Kogyo Kabushiki Corporation (Shoketsu) (defendant) began selling a similar device. However, Shoketsu’s device used a single two-way sealing ring, and its sleeve was made of non-magnetizable material. Festo sued Shoketsu for patent infringement, arguing that Shoketsu’s device infringed under the doctrine of equivalents. Shoketsu argued that Festo was estopped from asserting the doctrine of equivalents because Festo had narrowed its patent claims during the application process. The district court ruled for Festo. The United States Court of Appeals for the Federal Circuit affirmed. The Supreme Court vacated the ruling and remanded the case to consider its recent decision in Warner-Jenkinson v. Hilton Davis Chemical. On remand, the Federal Circuit ruled for Shoketsu. The Supreme Court granted certiorari.
Rule of Law
Issue
Holding and Reasoning (Kennedy, J.)
What to do next…
Here's why 804,000 law students have relied on our case briefs:
- Written by law professors and practitioners, not other law students. 46,300 briefs, keyed to 988 casebooks. Top-notch customer support.
- The right amount of information, includes the facts, issues, rule of law, holding and reasoning, and any concurrences and dissents.
- Access in your classes, works on your mobile and tablet. Massive library of related video lessons and high quality multiple-choice questions.
- Easy to use, uniform format for every case brief. Written in plain English, not in legalese. Our briefs summarize and simplify; they don’t just repeat the court’s language.
