91 L. Ed. 2d 265 (1986). When Rule 56(e) shifts the burden of proof to the nonmoving party, it must produce evidence to show the existence of every essential element which it must prove at trial. Equimark, 812 F.2d at 144.
A. The Literal Infringement Claim
Literal infringement requires that the accused device embody every element of the patentee's claim. Townsend Eng'g Co. v. Hitec Co., 829 F.2d 1086, 1090 (Fed. Cir. 1987). Trinity maintains that the Aluminator II does not literally infringe claims 1 or 6 of the '097 patent because the longitudinal axes of the troughs on the Aluminator II are not parallel to the longitudinal axis of the car's center sill. Johnstown disagrees, contending that the axes are indeed parallel.
This dispute boils down to the correct definition of "longitudinal axis" of a trough. Both parties have submitted affidavits by engineering experts. Trinity has submitted the affidavit of Dr. Glenn Sinclair, a professor of mechanical engineering at Carnegie Mellon University. Johnstown has submitted the affidavit of Dr. James Romualdi, a professor of civil engineering at Carnegie Mellon and president of Romualdi, Davidson and Associates, Inc., an engineering consulting firm.
Dr. Sinclair defines the longitudinal axis of a trough as "the straight line running lengthwise through the centers of the vertical cross sections at the ends of the trough. The center of the vertical cross section at the end of a trough may be taken as either the centroid of the cross section, or the center of gravity." Sinclair affidavit, Docket No. 40, P 10. Dr. Sinclair states that the longitudinal axis of a trough in the Aluminator II is in fact two axes, each of which slopes up (with the trough) from one end of the car to the middle. Because these two axes slope, they are not parallel to the horizontal axis of the center sill. Id. at PP 9, 17, 23; supplemental Sinclair affidavit, Docket No. 54, P 11.
Dr. Romualdi neither disagrees with Dr. Sinclair's definition nor provides his own. Indeed, he cites Dr. Sinclair's definition with apparent approval. See Romualdi affidavit, Docket No. 47, PP 13, 14, 17, 20, 22. When Dr. Romualdi applies that definition to the troughs in the Aluminator II, however, he reaches a conclusion different from Dr. Sinclair's. Dr. Romualdi maintains that "the straight line running lengthwise through the centers of the vertical cross sections at the ends of the trough" is exactly that: a straight line running from the center of one end of the trough to the center of the other end, no matter how many bends or twists or turns the trough might take. Because a trough in the Aluminator II starts and ends at the same height above the center sill, Dr. Romualdi's interpretation of the longitudinal axis of each trough is a horizontal line. Accordingly, it is parallel to the horizontal longitudinal axis of the center sill. Id. PP 17, 22.
I conclude that Dr. Sinclair's definition and interpretation of "longitudinal axis" of a trough are correct. I base my determination on the geometrical definition of "axis": "a line about which a geometrical figure is symmetrical." American Heritage Dictionary of Science 55 (1986), copy attached as Exh. D to Sinclair affidavit, Docket No. 40. In the Aluminator II, the line about which each trough is symmetrical cannot be, as a matter of geometry, a horizontal line from one end of the trough to the other. That would be the case only for a horizontal trough, as in the '097 patent. Once one bends the trough, as in the Aluminator II, the trough becomes symmetrical about two lines, each of which slopes up (with the trough) from either end of the car to the middle. Determining a longitudinal axis in a solid figure which is, as Dr. Sinclair states, "geometrically continuous," such as a cylinder or a cone, is different from determining a longitudinal axis in a geometrically discontinuous figure, such as a "bent" cylinder or a cone.
"The method of locating a longitudinal axis must be applied to each of the parts of the floor structure in the Aluminator II car that are separated by the geometric discontinuity." Supplemental Sinclair affidavit, Docket No. 54, at P 11 (emphasis added).
My conclusion is based on geometry. It does not derive from a credibility determination made after comparing the curricula vitae of the two experts. Indeed, both parties' experts present impressive credentials. Because the experts disagree, one might mistakenly conclude that the question of which party has correctly defined "longitudinal axis" of a trough is a question of fact to be determined by a jury after hearing testimony from both sides' experts. Claim interpretation is, however, a question of law. See, e.g., Texas Instrs., Inc. v. United States Int'l Trade Comm'n, 988 F.2d 1165, 1171 (Fed. Cir. 1993). Claim interpretation includes determining the meaning of a term in a claim. Even when such a determination requires the consideration of extrinsic evidence, such as conflicting expert testimony, it remains a question of law. See, e.g., id.; Hormone Research Found. v. Genentech Inc., 904 F.2d 1558, 1562, 1563 n.7 (Fed. Cir. 1990), cert. dismissed, 499 U.S. 955 (1991); Johnston v. IVAC Corp., 885 F.2d 1574, 1579-80 (Fed. Cir. 1989); Tandon Corp. v. United States Int'l Trade Comm'n, 831 F.2d 1017, 1021 (Fed. Cir. 1987) (citing H.H. Robertson Co. v. United Steel Deck, Inc., 820 F.2d 384, 389 (Fed. Cir. 1987); SRI Int'l v. Matsushita Elec. Corp., 775 F.2d 1107, 1117 n.11, 1118 (Fed. Cir. 1985)). Accordingly, what is the correct definition of "longitudinal axis" is a question of law, and it is within the province of this Court to resolve the issue on summary judgment. See, e.g., Johnston, 885 F.2d at 1580 (when the patentee's claims do not read on the accused device exactly, a finding of no literal infringement on summary judgment is proper).
B. The Infringement Claim Under the Doctrine of Equivalents
Johnstown asserts that even if the Trinity patent does not literally infringe claims 1 or 6 of the '097 patent, it infringes those claims under the doctrine of equivalents. Under that doctrine, Trinity is liable for infringement if the Aluminator II performs "substantially the same function in substantially the same way to achieve substantially the same result" as the '097 patent. Malta v. Schulmerich Carillons, Inc., 952 F.2d 1320, 1325 (Fed. Cir. 1991), cert. denied, 119 L. Ed. 2d 566, 112 S. Ct. 2942 (1992). Whether the two are equivalents is a question of fact. Id.
Although Trinity acknowledges that equivalency cannot be determined on summary judgment because it is a question of fact, it argues that Johnstown is estopped from pursuing its equivalency claim under the rule known as prosecution history estoppel or "file wrapper estoppel." prosecution history estoppel "bars a patentee from enforcing its claims against otherwise legally equivalent structures if those structures were excluded by claim limitations added in order to avoid prior art." Vaupel Textilmaschinen KG v. Meccanica Euro Italia S.P.A., 944 F.2d 870, 882 (Fed. Cir. 1991) (quotation omitted). Conversely, prosecution history estoppel does not apply when claim language is amended for some reason other than to avoid prior art. Therefore, "in determining whether prosecution history estoppel applies because of a change in claim language during prosecution, the court must consider not only what was changed, but the reason for such change." Id. As the Federal Circuit has explained,
Amendment of claims is a common practice in prosecution of patent applications. No reason or warrant exists for limiting application of the doctrine of equivalents to those comparatively few claims allowed exactly as originally filed and never amended. Amendments may be of different types and may serve different functions. Depending on the nature and purpose of an amendment, it may have a limiting effect within a spectrum ranging from great to small to zero.
Hughes Aircraft Co. v. United States, 717 F.2d 1351, 1363 (Fed. Cir. 1983).
Whether prosecution history estoppel applies is a question of law. Hoganas AB v. Dresser Indus., 9 F.3d 948, 952 (Fed. Cir. 1993). Trinity maintains that prosecution estoppel applies here because Johnstown, in prosecuting its application for the '097 patent, specifically amended the language of claims 1 and 6 to limit those claims to railway cars with troughs whose longitudinal axes are parallel to the longitudinal axis of the center sill.
I am unpersuaded. Although the term "longitudinal axis" was added by amendment, the parallelism requirement was not; claims 1 and 6 in Johnstown's original application described "a pair of concave floor panels, each panel extending parallel to said center sill." Because the parallelism requirement existed even before the claims language was amended, it is beyond dispute that the purpose of amending claims 1 and 6 by adding the term "longitudinal axis" was not to impose parallelism as a "new" limitation on Johnstown's invention.
The parallelism requirement of the Johnstown invention always distinguished it from the Kuehner patent, even before the term "longitudinal axis" was added. Although Trinity correctly notes that the patent examiner rejected Johnstown's application because he determined that the Kuehner patent contained every element of Johnstown's invention, I am not bound by the examiner's decision on that point -- particularly as his decision clashes with the language in Johnstown's application. See, e.g., In re Baxter Travenol Labs, 952 F.2d 388, 390 (Fed. Cir. 1991) (anticipation under 35 U.S.C. § 102 is a question of fact, and a court will reverse a finding of anticipation if clearly erroneous); see also Axia Inc. v. Jarke Corp., 1989 U.S. Dist. LEXIS 4200, 12 U.S.P.Q.2D (BNA) 1049, 1053 (N.D. Ill. 1989) ("There is . . . support for not applying prosecution history estoppel where a claim is amended in response to an examiner's incorrect rejection.") (citing Great Northern Corp. v. Davis Core & Pad Co., 782 F.2d 159, 166 (Fed. Cir. 1986)). It cannot be said that the Kuehner patent, which claimed "[downwardly] inclined trough shaped chute[s] extending longitudinally of the car," anticipated Johnstown's invention, which uses "a pair of concave floor panels, each panel extending parallel to said center sill." Inclined troughs cannot be parallel to a center sill because a sill is, by definition, horizontal. See Webster's New World Dictionary 1249 (3d college ed. 1988).
If the purpose of adding the words "longitudinal axis" to claims 1 and 6 was not to distinguish Johnstown's invention from the Kuehner patent, what, then, was its purpose? The only reasonable explanation is that it provided a technical refinement in: terminology. The original patent application required that the troughs be parallel to the center sill, whereas the issued patent requires that the longitudinal axes of the troughs be parallel to the longitudinal axis of the sill. The only effect of this change is to specify the two lines -- rather than the two parts of the car -- which must be parallel. It appears that this change was made to simplify and clarify the parallelism requirement. One could anticipate disputes arising under the original language over what part of the trough and what part of the sill one measures from when determining whether they are parallel. Under the amended language, such disputes are less likely to arise.
Prosecution history estoppel applies where a claim is amended to add a new limitation over prior art, not where, as here, a claim is amended to describe an existing limitation with more technically precise language. See, e.g., Andrew Corp. v. Gabriel Elec., Inc., 847 F.2d 819, 825 (Fed. Cir.) (prosecution history estoppel did not apply where claim language was amended "for the purposes of explication and clarity"), cert. denied, 488 U.S. 927, 102 L. Ed. 2d 330, 109 S. Ct. 312 (1988). As no bar exists to Johnstown's infringement claim under the doctrine of equivalents, Johnstown may pursue that claim at trial.
An appropriate order follows.
AND NOW, this 2nd day of September, 1994, consistent with the foregoing opinion, defendant's motion for summary judgment (Docket No. 38) is granted in part. It is hereby ORDERED that defendant's motion is GRANTED as to plaintiff's claim for literal infringement, but DENIED as to plaintiff's claim for infringement under the doctrine of equivalents.
This case will be listed on the November 1994 trial term for Johnstown.
BY THE COURT,
D. Brooks Smith
United States District Court
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