After losing three in a row to hybrid technology company Paice, first by jury verdict in the district court, then in the court of appeals and then being rejected by the Supremes, the Toyota Prius has finally prevailed in a patent infringement suit. Earlier this month, the U.S. Court of Appeals for the Federal Circuit (the court that hears appeals of patent decisions from district courts and administrative agencies) held that Toyota did not infringe a patent owned by Connecticut hybrid technology company Solomon Technologies (Solomon).
Solomon’s U.S. Patent No. 5,067,932 (‘932 patent) covers a combination motor and transmission device having a continuously variable speed of rotation. According to the patent, the invention permits a hybrid engine to operate at peak power over a greater range of rotational speed, or rpm.
As is often the case in patent litigation, claim construction (the court’s interpretation of the legal scope of a patent’s claim language) was critical here. The disputed language was in claim 7 of the ‘932 patent, which requires an “integral combination” of a motor element and a transmission unit element and requires that one of the two elements be located “within an envelope” containing the other element.
The Federal Circuit affirmed that the “integral combination” element means the motor and transmission are directly attached without the presence of shafts, bearings or other components in between. Because Toyota’s transaxles have rotor shafts between the motor-generators and the transmission unit, the court found they did not infringe.
The court also held that the term “within an envelope” means that one of the two elements (motor or transmission unit) is within the imaginary space defined by the rotation of the other element. As an additional basis for non-infringement, the Federal Circuit found that Toyota’s transmission gears were outside of the imaginary space defined by the motors’ magnet assemblies.