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No Interference−in−Fact Exists Because, Applying the Proper Construction, Junior Patent Is Not Obvious over Senior Reissue Application

May 05, 2010

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Last Month at the Federal Circuit - June 2010

Judges: Michel, Rader (author), Schall

[Appealed from: E.D. Va., Judge Brinkema]

In Rolls−Royce, PLC v. United Technologies Corp., No. 09−1307 (Fed. Cir. May 5, 2010), the Federal Circuit held that Rolls−Royce, PLC’s (“Rolls−Royce”) junior patent would not have been obvious over United Technologies Corp.’s (“UTC”) senior reissue application, thereby determining that there was no interference−in−fact. 

In 2003, the Board declared an interference between Rolls−Royce’s U.S. Patent No. 6,071,077 (“the ’077 patent”) and UTC’s Reissue Application No. 09/874,931 (“the ’931 reissue application”).  Based on the earliest available priority dates, the Board named UTC the senior party.  Rolls−Royce did not contest its designated priority.  The Board defined a single interference count corresponding to claim 23 of UTC’s ’931 reissue application and claim 8 of Rolls−Royce’s ’077 patent.  Both claims are directed to a stage of a gas turbine engine, which can be used to power aircraft.  The claims require a fan blade with a swept−forward inner region, a swept−rearward intermediate region, and an outer region with recited properties.  At issue was the limitation, recited in UTC’s claim 23, that “the outer region be[] translated forward relative to a leading edge with the same sweep angle as an outward boundary of the intermediate region to provide a sweep angle that causes the blade to intercept the shock.”  The Board construed that limitation as including fan blades with either forward or rearward sweep angles in their outer region.  On that basis, the Board entered final judgment in the interference proceedings in favor of UTC. 

On appeal from the Board, the district court rejected the Board’s construction as overly broad.  After receiving testimonial and documentary evidence in a three−day bench trial, the district court concluded that the disputed limitation, recited in UTC’s claim 23, did not include fan blades with a forward sweep angle in their outer region.  Applying its own construction, the district court held that Rolls−Royce’s ’077 patent was patentably distinct from UTC’s ’931 reissue application, and so there was no interference−in−fact. 

On appeal from the district court, the Federal Circuit focused its analysis on claim construction and obviousness.  Since the disputed limitation in UTC’s claim 23 did not clearly designate a “forward” direction for the recited translation of the outer region of the fan blade, the Court consulted UTC’s specification for clarification.  According to the Court, UTC’s specification discusses translation forward only with reference to the axial direction, which is parallel to the rotational axis of the fan and engine.  The Court thus construed “translated forward” to mean “moved forward toward the axial direction,” which it defined as parallel to the rotational axis of the fan and engine.  The Court rejected UTC’s proposed construction, “toward the relative velocity vector,” as overly broad because it could encompass the axial and circumferential directions, which are at right angles to each other.

The Court also consulted the specification to ascertain the meaning of the “sweep angle that causes the blade to intercept the shock,” recited in UTC’s claim 23.  UTC’s specification states that the sweep angle is nonincreasing (i.e., decreases, or at least does not increase) with increasing radius.  According to the Court, the invention emphasizes the critical character of the nonincreasing sweep angle in the tip region.  Thus, the Court construed the recited sweep angle as “a rearward sweep angle in the outer region that is constant or decreasing.”  Slip op. at 16.  The Court deemed any translation from the rearward sweep to a zero degree sweep to be decreasing.  The Court further deemed any translation from a zero degree sweep to a forward sweep, even if designated as a negative angle, as an increasing sweep and a direct contradiction to the requirements of the specification.  The Court notes for support that the specification teaches that the sweep angle must be nonincreasing with increasing radius.  Agreeing with the district court, the Court concluded that the outer region of a fan blade in accordance with UTC’s claim 23 could not include a forward sweep angle. 


UTC presented computational fluid dynamics (“CFD”) simulations by its expert, Dr. Yuan Dong, in support of its proposed constructions.  UTC argued that a person conducting such simulations at the time of the invention would have seen that, under at least some conditions, forward sweep in the outer regions of the fan blade was required to intercept shock.  With regard to the simulations, the Court noted that Dr. Dong equated endwall shock and passage shock, even though UTC’s specification states that they are unrelated.  According to the Court, endwall shock is not visible in the simulations.  Moreover, Dr. Dong translated the outer region of the fan blade in the direction of the relative velocity vector, not toward the axial direction.  The Court thus concluded that Dr. Dong’s simulations in no way overcome the intrinsic evidence in the specification that excludes forward sweep in the outer region. 

The primary issue with regard to a possible interference was the “outer region [of the fan blade] between the intermediate region and the fan casing, the outer region defining a forward sweep angle,” as recited in Rolls−Royce’s claim 8.  The Court began its interference analysis by noting that UTC’s specification does not disclose a fan blade with a forward swept outer region.  Indeed, UTC and Rolls−Royce stipulated that obviousness, not anticipation, is responsible for any interference.  Thus, the Court considered UTC’s argument that the forward swept outer region of Rolls−Royce’s claim 8 would be obvious from UTC’s specification.  “To preclude hindsight in this analysis, [the Court] flexibly [sought] evidence from before the time of the invention in the form of some teaching, suggestion, or even mere motivation (conceivably found within the knowledge of an ordinarily skilled artisan) to make the variation or combination.”  Id. at 21.

Relying in part on Dr. Dong’s simulations, UTC argued that forward sweep in the outer region would have been an easily predictable and achievable variation in view of the disclosure of rearward sweep in its specification.  The Court disagreed:  “Without some way of detecting benefits in reducing endwall shock or even a reason to seek that reduction in a new way, a researcher or artisan of ordinary skill would not reverse the direction of the sweep angle.”  Id.  The record before the invention, however, showed that translation forward in the axial direction may create an unusable fan blade and cause the endwall shock to move behind the passage shock.  According to the Court, such movement of the endwall shock might defeat the coincidence of shocks—the benefit heralded by UTC’s specification.  According to the Court, the record contained no evidence that would have suggested to or motivated an ordinarily skilled artisan to sweep the fan blade forward in the outer region.  Thus, the Court found that the record supports the district court’s conclusion that the variation recited in Rolls−Royce’s claim 8 would not have been obvious. 

UTC further argued that it would have been obvious to try to reverse the sweep angle from rearward to forward sweep in the outer region in order to intercept the endwall shock.  In the “obvious to try” analysis, “[t]he important question is whether the invention is an ‘identified, predictable solution’ and an ‘anticipated success.’”  Id. at 22 (citation omitted).  According to the Court, a person of ordinary skill would have a broad selection of choices for further investigation including any degree of sweep.  The Court concluded that because one of ordinary skill could not use CFD simulations to detect the endwall shock and no other evidence in the record gives a reason to reverse the sweep angle to intercept that shock, Rolls−Royce’s invention would not have presented itself as an option at all, let alone an option that would have been obvious to try. 

Finally, the Court noted that the secondary considerations in the case reinforce and substantiate the conclusion of nonobviousness.  In particular, the district court found that Rolls−Royce’s invention fulfilled a long−felt but unresolved need, achieved commercial success, and also received industry acclaim from the inventor’s peers.  The district court found the testimony of Rolls−Royce’s Vice President of Marketing about the need for quieter, more fuel−efficient engines compelling.  At the time of the invention, swept fan blades were known to become unstable during operation.  Nonetheless, Rolls−Royce built a fan blade that physically embodied claim 8.  Computer analysis predicted that that blade had a dramatic efficiency improvement and, more importantly, that it would be stable due to the forward sweep at the tip.  Rolls−Royce’s first commercially available engine including the claim 8 fan blade was characterized by high efficiency, low noise, and stability, and also received substantial industry acclaim.  The nexus between the commercial success and the patentably distinct feature was established by the district court’s finding that the fan blade benefits were a major driving force behind the sales of Rolls−Royce engines that incorporate them.

Summary authored by Kia L. Freeman, Esq.