District Court Erred in Defining "Rear End" By Exterior Tube Dimensions

Case: Research Plastics, Inc. v. Federal Packaging Corp., 04-1605 (Fed. Circ., 8/18/05)

The One Sentence Summary: The Federal Circuit vacated a finding of non-infringement on summary judgment, holding that the lower court incorrectly construed the term "rear end" to be defined by the exterior rear edge of a tube, rather than defining it by both the interior and exterior rear edges of the tube.

What They Were Fighting About: The patent provided for use of ribs inside a tube (like those used for caulking) to allow for the release of air through the nozzle along with whatever material was extruded from the tube, with the ribs present from the "rear end" of the tube to the nozzle. The plaintiff claimed infringement when a competitor marketed tubes with ribs in the rear half but which arguably did not extend all the way back to the rear end, depending on how 'rear end' was defined.

Federal Circuit Holdings:

• To obtain the patent and overcome an objection based on obviousness, the inventor had distinguished prior art by including the limitation that the ribs extend to the rear end of the tube, because a prior tube design used ribs near the nozzle as a means of releasing trapped air when the tube was filled.
• The defendant marketed tubes with a bevelled rear end, such that the exterior wall is longer than the interior, and the tube widens towards the back edge. The tapered portion is referred to as the chamfer angle. Ribs extended from the interior rear wall forward, but did not go as far back as the edge of the exterior rear wall.
• At the Markman hearing, the lower court adopted the defendant's construction, holding that 'rear end' means the outermost exterior edge of the tube and 'nozzle end' means the point on the forward edge of the tube body. It further noted that the claim language implied that the rear end was a point on the tube, not an area, and the diagrams pointed to the edge of the tube. It concluded that the chamfer angle was part of the tube body, because it was inside of the rear end -- thus there was no infringement where ribs began at the inside rear wall.
• The Federal Circuit held that rear end should include the entire rear edge of the tube, including the point at the rear end on the interior, and the point at the rear end on the exterior. In short, the chamfer angle was part of the rear end. Thus, while the lower court was right that 'rear end' referred to a point, not an area, it was wrong in locating that point beyond the chamfer angle. The case was remanded to reconsider whether there was infringement, given this new construction of the term
• The Federal Circuit upheld the lower court's finding that the plaintiff's narrowing amendment, in which it specified that the ribs were located all the way back to the rear end of the tube, estopped it from relying on the doctrine of equivalents to show infringement.