Stratoflex, Inc. v. Aeroquip Corp.
United States Court of Appeals for the Federal Circuit
713 F.2d 1530 (1983)
Aeroquip Corporation (Aeroquip) (defendant) and Stratoflex, Inc. (Stratoflex) (plaintiff) were competitors in the business for polytetraflouroethylene (PTFE) tubing. PTFE tubing could be made conductive through the use of conductive fillers, but the practice tended to make leaking more prevalent due to the emergence of gaps between filler particles and the PTFE material. Hoping to address the leaking problems that plagued conductive PTFE tubing, Aeroquip assigned two engineers to isolate the cause. The engineers determined that the leakage was due to electrical erosion and that the consequent gaps in the PTFE tubing were preventing conductivity. To solve the problem, Aeroquip ultimately developed a composite tube that included both a layer of PTFE and a layer of PTFE interspersed with highly conductive filler called carbon black. Aeroquip obtained a patent for the composite tubing (the ‘087 patent). Eventually, Stratoflex began manufacturing its own version of composite tubing, which had an inner layer of PTFE featuring evenly dispersed carbon-black filling. Aeroquip believed that Stratoflex’s use of the composite tubing amounted to patent infringement, and Stratoflex responded with a declaratory-judgment action to determine the validity of the ‘087 patent. Aeroquip counterclaimed for patent infringement. The district court held that several claims of the ‘087 patent were obvious in light of prior art and that Stratoflex had not infringed upon the only non-obvious claim of the ‘087 patent. Aeroflex appealed the findings of invalidity and non-infringement.
Rule of Law
Holding and Reasoning (Markey, C.J.)
What to do next…
Unlock this case brief with a free (no-commitment) trial membership of Quimbee.
You’ll be in good company: Quimbee is one of the most widely used and trusted sites for law students, serving more than 97,000 law students since 2011. Some law schools—such as Yale, Vanderbilt, Berkeley, and the University of Illinois—even subscribe directly to Quimbee for all their law students. Read our student testimonials.
Learn more about Quimbee’s unique (and proven) approach to achieving great grades at law school.
Quimbee is a company hell-bent on one thing: helping you get an “A” in every course you take in law school, so you can graduate at the top of your class and get a high-paying law job. We’re not just a study aid for law students; we’re the study aid for law students. Read more about Quimbee.
Here's why 175,000 law students have relied on our case briefs:
- Written by law professors and practitioners, not other law students. 14,000 briefs, keyed to 188 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.