A "sump" is an underground container which provides easy access to underground components, such as the fill and evacuation pipes of an underground fuel tank, via a removable cover or lid situated essentially flush with ground level. In addition to providing easy component access, a well-sealed "containment sump" (or "containment manhole") can also provide protection against environmental contamination during the filling and evacuation process.

Asserted claim 1 went to a "sump cover containment assembly." The outcome of the case focused on defining the scope of the claim term "facilitate positioning."

In the proceedings below, a primary dispute between the parties was the proper construction of "facilitate positioning" in claim 1. OPW argued that the term means to "assist in positioning and support," JA at 96, whereas Franklin argued that it "means only that the opening be large enough to 'allow' a spill collector to be positioned in the hole," JA at 20.

The district court looked for definition within the claim language, the figures, the specification, and the prosecution history. To overcome an obviousness rejection, the inventor had seemingly narrowed the claim term definition, leading the court to adopt OPW's narrower construction. Based upon the claim construction, the district court found that the defendant's product lacked a claimed element, and thus did not infringe.

The CAFC did not find support for the narrow construction in the spec or figures, noting that patent figures have limited utility for discerning claim term definition. The CAFC reminded that claim language is self-contained unless referential or ambiguous; and that the preferred embodiment is not necessarily read into the claim.

Perhaps the most notable aspect of the specification is that although it contemplates contact between the downward extension and the spill collector, there is no mention of contact between the upward extension and the spill collector. Admittedly, figure 7 appears to depict contact between the right side of the spill collector and the upward extension. Yet, a close examination of figure 7 also reveals that any such contact might be incidental because, on the opposite side of the spill collector, there is a small but distinctive space between the upward extension and the spill collector. The only arguable contact in that portion of the figure is provided by an ambiguous line extending from the top of the upward extension to the side of the spill collector. That line might have been intended to indicate a connection, it might have been accidental, or it might have been intended to indicate something else altogether.

We need not resolve the ambiguity here because patent figures are generally not intended to convey such detail. Cf. Hockerson-Halberstadt, Inc. v. Avia Group Int'l, 222 F.3d 951, 956 (Fed. Cir. 2000) ("Under our precedent . . . it is well established that patent drawings do not define the precise proportions of the elements and may not be relied on to show particular sizes if the specification is completely silent on the issue."). Moreover, even if figure 7 unambiguously depicted contact between the upward extension and the left side of the spill collector, as it seems to depict between the upward extension and the right side of the spill collector, we would not necessarily conclude that such contact is a required limitation of the claims because figure 7 is merely a preferred embodiment of the invention. '257 patent col.5 ll.42-48. See Burke, Inc. v. Bruno Indep. Living Aids, Inc., 183 F.3d 1334, 1341 (Fed. Cir. 1999) ("[A]n attribute of the preferred embodiment cannot be read into the claim as a limitation."). Put simply, any contact inferable from figure 7 is not relevant to our claim construction analysis. Accordingly, we find nothing in the specification indicating that the term "facilitate positioning" requires physical contact.

The CAFC didn't find an "it" in a prosecution office action reply to be as damningly narrowing as the district court had.

The word "It" plainly refers to "the invention of amended claim 1," see JA at 369 (emphasis added), and therefore encompasses the entire claimed assembly; "It" does not refer to the upward and downward extensions alone. At most, the inventor disclaimed any apparatus in which the spill collector is not supported by something within the assembly. However, there is no requirement that the support be provided by physical contact with both the upward and downward extensions. The mere fact that the preferred embodiment depicted in figure 7 shows physical contact between the spill collector and the downward extension does not mean that such contact is a claim limitation, see Burke, 183 F.3d at 1341, and it certainly does not mean that contact between the spill collector and the upward extension is a claim limitation.

Another point of note: for an apparatus claim, the assembly process is irrelevant to infringement analysis.

[A] proper infringement analysis requires a comparison of the limitations of the claims to the accused device, regardless of what process was used to assemble the device.

Remanded for infringement analysis based on the broader claim construction.