The district court erred in its construction of the term “said flow control orifice being constantly operative” in claims 5 and 12 of the '284 patent.

The district court's construction improperly discounted the prosecution history in rejecting Appellants' proposed construction. The court's error was particularly egregious since the prosecution history is especially pertinent in construing the term, which was added by amendment and appears nowhere in the '284 patent except in claims 5 and 12. A review of the amendment that added the term shows that the patentee clearly meant to distinguish the claimed constantly operative flow control orifice from the prior art, because the claimed orifice was always positioned in its associated hydraulic fluid line rather than being switchable in and out of the circuit as in the cited prior art reference.

The district court also ignored the disclosure of the '284 patent as a whole, instead seizing upon a single word in the specification and claims to justify construing the claim term in terms of dynamic flow conditions and requiring the flow control orifice to continuously slow fluid flow irrespective of whether there was any fluid flow present.

The district court justified its construction as preventing the word “even” in claims 5 and 12 from becoming superfluous. The result of its construction, however, is to render several aspects of the claims redundant or superfluous.

This Court should vacate the district court's construction of the term “said flow control orifice being constantly operative” and provide the district court with the correct construction or instructions to construe the term in a manner consistent with the specification and prosecution history of the '284 patent, preferably a construction that is based on structure and not dependent on dynamic flow conditions. Finally, the district court's Final Judgment Order invalidating claims 5 and 12 for failing to meet the written-description requirement of 35 U.S.C. § 112 should be vacated.

The district court correctly construed the claim phrase “said flow control orifice being constantly operative” to mean “[t]he flow control orifice continuously slows fluid flow when the first control valve is in the open or closed posi-tion.”

First, the district court's construction is supported by the plain language of the claims, the written description, and the drawings of the 284 patent. Indeed, the plain language of claim 5 unambiguously imposes the requirement that the flow control orifice be constantly operative, whether the first control valve is in the open or closed position. Spe-cifically, claim 5 requires that the “third fluid line allow[] a flow of hydraulic fluid from said second fluid line to said first fluid line even when said control valve is in a closed position.” (emphasis added). That requirement is ech-oed in the specification. See A47; col. 2, 1. 16-19 (“The third fluid line allows a flow of hydraulic fluid between the first and second fluid lines even when the control valve is in a closed position.”) (emphasis added); A50, col. 7, 1. 27-29 (“Hydraulic fluid is thus able to circulate between [first and second] fluid lines 114' and 124' … by way of the third fluid line even when the [control] valve 200 is in the closed position.”) (emphasis added).

Second, the district court's construction gives meaning to all of the words in claims 5 and 12. Again, claim 5 re-quires that the “third fluid line allow a flow of hydraulic fluid from said second fluid line to said first fluid line even when said control valve is in a closed position.” (emphasis added). As Alamo argued and the district court con-cluded, the only logical explanation for the use of the word “even” in claim 5 is that the third fluid line allows a flow of hydraulic fluid from the second fluid line to the first fluid line when the control valve is in an open or closed posi-tion. Otherwise, the word “even” would be rendered superfluous. Remarkably, Cartner has never offered an alterna-tive explanation for the term “even” in claim 5 or explained how any one of its panoply of alternative constructions gives meaning to that term.

Finally, the district court's construction is in accord with this Court's en banc decision in Phillips v. AWH Corp., 415 F.3d 1303 (Fed. Cir. 2005), in that it affords the appropriate weight to the claims, the specification, and the prosecu-tion history of the 284 patent. Contrary to Cartner's argument, the referenced dictionary played no role, let alone the significant role that Cartner attributes to it, in any substantive dispute over the meaning of the disputed phrase. Rather, the resolution of the parties' substantive dispute in Alamo's favor turned on the plain language of the claims, as supported by the patent's written description and drawings. Further, the district court properly gave less weight to the prosecution history of the 284 patent, which it found was “not explanatory” (A33), a decision that appears even more unassailable now in view of Cartner's efforts to cast that history in a supporting role for each of the “alterna-tive” constructions (including one that is new on this appeal) that Cartner has offered since the district court issued its Markman ruling.

For all of these reasons, as detailed more fully below, the district court's judgment should be affirmed in its entirety.