LITTELFUSE, INC., Plaintiff-Appellant v. MERSEN USA EP CORP., Defendant-Appellee
2021-2013
United States Court of Appeals for the Federal Circuit
April 4, 2022
Appeal from the United States District Court for the District of Massachusetts in No. 1:17-cv-12375-IT, Judge Indira Talwani.
THOMAS E. BEJIN, Bejin Bieneman PLC, Southfield, MI, argued for defendant-appellee. Also represented by WILLIAM K. BROMAN; MARTIN F. GAYNOR, Hunton Andrews Kurth LLP, Boston, MA.
Before PROST, BRYSON, and STOLL, Circuit Judges.
Appellant Littelfuse, Inc., brought a patent infringement action against appellee Mersen USA EP Corp. After the district court construed the patent claims, the parties stipulated to a judgment of non-infringement. Littelfuse now appeals the district court‘s claim constructions. We vacate and remand.
I
A
Littelfuse alleges that Mersen infringes U.S. Patent No. 9,564,281 (“the ‘281 patent“). The ‘281 patent is directed to a “fuse end cap for providing an electrical connection between a fuse and an electrical conductor.” ‘281 patent, Abstract. Each of the embodiments of a fuse end cap disclosed in the specification comprises a “mounting cuff” that receives the body of a fuse and a “terminal” that receives an electrical conductor. The specification first describes a generic embodiment of the fuse end cap. Id. at col. 2, line 61, through col. 4, line 67. The specification then describes three embodiments: a “machined end cap,” id. at col. 5, ll. 1–26; a “stamped end cap,” id. at col. 5, ll. 27–52; and an “assembled end cap,” id. at col. 5, line 53, through col. 6, line 21.
According to the specification, the machined end cap may be manufactured from a “single piece of any suitable, electrically conductive material” and may be created by “machining, cold heading, or otherwise forming” the features of the fuse end cap through use of a machining tool. Id. at col. 5, ll. 16–26. The stamped end cap may also be formed from a “single piece of any suitable, electrically conductive material” and may be created by stamping a single piece of conductive material. Id. at col. 5, ll. 42–48. That is, the stamped end cap may be created by “bending, folding, and pressing a sheet of conductive material.” Id. at col. 5, ll. 49–52.
Independent claim 1 of the ‘281 patent recites:
1. A fuse end cap comprising:
a mounting cuff defining a first cavity that receives an end of a fuse body, the end of the fuse body being electrically insulating;
a terminal defining a second cavity that receives a conductor, wherein the terminal is crimped about the conductor to retain the conductor within the second cavity; and
a fastening stem that extends from the mounting cuff and into the second cavity of the terminal that receives the conductor.
Dependent claims 8 and 9 also play a significant role in this dispute. They recite:
8. The fuse end cap of claim 1, wherein the mounting cuff and the terminal are machined from a single, contiguous piece of conductive material.
9. The fuse end cap of claim 1, wherein the mounting cuff and the terminal are stamped from a single, contiguous piece of conductive material.
10. A fuse assembly comprising:
a first fuse end cap having a mounting cuff defining a first cavity and a terminal defining a second cavity;
a fastening stem that extends from the mounting cuff of the first fuse end cap and into the second cavity of the terminal;
a second fuse end cap having a mounting cuff defining a first cavity and a terminal defining a second cavity, and a fastening stem that extends from the mounting cuff of the second fuse end cap and into the second cavity of the terminal . . . .
Claims 19 and 20, which depend from claim 10, recite as follows:
19. The fuse end cap of claim 10, wherein each fuse end cap is machined form a single, contiguous piece of conductive material.
20. The fuse end cap of claim 10, wherein each fuse end cap is stamped from a single, contiguous piece of conductive material.
B
A brief discussion of the prosecution of the ‘281 patent provides context for the present dispute. During prosecution of the ‘281 patent, the examiner issued a restriction requirement, noting that each of the three embodiments disclosed in the specification represented a distinct species. J.A. 493. Littelfuse responded by electing to prosecute the species corresponding to the “assembled end cap” embodiment. J.A. 487. The examiner then withdrew dependent
In the initial application filed by Littelfuse, claim 1 recited only the “mounting cuff” and “terminal” limitations. J.A. 197. Similarly, claim 10 initially recited limitations pertaining to the mounting cuff and terminal, but did not include a limitation directed to a fastening stem. J.A. 198. After an initial rejection by the examiner under
C
In the course of the litigation, the district court construed the term “fastening stem” to mean a “stem that attaches or joins other components.” Littelfuse, Inc. v. Mersen USA Newburyport-MA, LLC (Claim Construction Order), No. 1:17-CV-12375, 2020 WL 9071704, at *9 (D. Mass. Mar. 6, 2020). The court construed the phrase “a fastening stem that extends from the mounting cuff and into the second cavity of the terminal that receives the conductor” to mean “a stem that extends from the mounting cuff and into the second cavity of the terminal that receives the conductor, and attaches the mounting cuff to the terminal.” Id. In further clarifying its constructions, and in
Although not expressly stated in the parties’ stipulation of non-infringement, the parties have made clear on appeal that their decision to stipulate to non-infringement was based on an understanding that under the district courts’ constructions claims 1 and 10 covered only a multi-piece apparatus. See Oral Argument at 19:03–20:09, 40:00–40:23. That understanding is consistent with our reading of the district court‘s orders.
II
We review the district court‘s claim construction and interpretations of intrinsic evidence de novo and any subsidiary factual findings for clear error. Apple Inc. v. Wi-LAN Inc., 25 F.4th 960, 967 (Fed. Cir. 2022).
A
To begin with, we disagree with the district court‘s conclusion that claims 1 and 10 cover only a multi-piece apparatus. A claim term is generally given the “meaning that the term would have to a person of ordinary skill in the art in question at the time of the invention.” Phillips v. AWH Corp., 415 F.3d 1303, 1313 (Fed. Cir. 2005) (en banc). How the term is used in the claims and the specification of the
The structure of the claims is enlightening. Independent claims 1 and 10 recite a fuse end cap comprising three elements: a mounting cuff, a terminal, and a fastening stem. ‘281 patent, claim 1. Dependent claims 8, 9, 19, and 20 further limit claims 1 and 10 by requiring that the end cap be formed “from a single, contiguous piece of conductive material.” ‘281 patent, claims 8–9, 19–20.
By definition, an independent claim is broader than a claim that depends from it, so if a dependent claim reads on a particular embodiment of the claimed invention, the corresponding independent claim must cover that embodiment as well. See Baxalta Inc. v. Genentech, Inc., 972 F.3d 1341, 1346 (Fed. Cir. 2020) (“The district court‘s construction [of the independent claim] which excludes these explicitly claimed embodiments [in the dependent claims] is inconsistent with the plain language of the claims.“). Otherwise, the dependent claims would have no scope and thus be meaningless. A claim construction that leads to that result is generally disfavored. See Intellectual Ventures I LLC v. T-Mobile USA, Inc., 902 F.3d 1372, 1378 (Fed. Cir. 2018); Trs. of Columbia Univ. v. Symantec Corp., 811 F.3d 1359, 1370 (Fed. Cir. 2016); Wright Med. Tech., Inc. v. Osteonics Corp., 122 F.3d 1440, 1445 (Fed. Cir. 1997) (“[W]e must not interpret an independent claim in a way that is inconsistent with a claim which depends from it.“). Accordingly, the recitation of a single-piece apparatus in claims 8, 9, 19, and 20 is persuasive evidence that claims 1 and 10 also cover a single-piece apparatus.
We note that the presumption of differentiation in claim scope is “not a hard and fast rule.” Seachange Int‘l, Inc. v. C-COR, Inc., 413 F.3d 1361, 1369 (Fed. Cir. 2005). Indeed, “any presumption created by the doctrine of claim differentiation ‘will be overcome by a contrary construction dictated by the written description or prosecution history.‘”
The district court recognized the inconsistency between its conclusion that claims 1 and 10 cover only a multi-piece apparatus and the recitation of a single-piece apparatus in claims 8, 9, 19 and 20. The court resolved that inconsistency by inferring that the examiner‘s re-joinder of those dependent claims was based “on a misunderstanding of those claims.” Claim Construction Order at *7.
The record in this case, however, does not support the conclusion that the examiner made a mistake in re-joining claims 8, 9, 19, and 20. In re-joining those claims, the examiner observed that those dependent claims “require all the limitations of the . . . allowable claims.” J.A. 322–23. That observation was logical, as the independent claims are not limited to a multi-piece construction and the dependent claims form a coherent invention in that they each
Turning to the specification, it is true that the detailed description refers to a “fastening stem” only with respect to the “assembled end cap” embodiment, which is a multi-piece apparatus. ‘281 patent, col. 6, ll. 1–21. But as we have cautioned, courts ordinarily should not limit “the claimed invention to preferred embodiments or specific examples in the specification.” Teleflex, Inc. v. Ficosa N. Am. Corp., 299 F.3d 1313, 1328 (Fed. Cir. 2002) (quoting Comark Commc‘ns, Inc. v. Harris Corp., 156 F.3d 1182, 1186 (Fed. Cir. 1998)). Nothing in the specification states that a fastening stem cannot be present in a single-piece apparatus. The specification describes the fastening stem as “projecting from a side of the mounting cuff 460 opposite the cavity 425.” ‘281 patent, col. 6, ll. 1–3. One can envision a stem that projects from the side of the mounting cuff even in an embodiment in which the fuse end cap is formed from a single piece of material.2
B
With that said, it is important to note that the district court was correct in seeking to give meaning to the term “fastening stem” by looking to the meaning of the words “fastening” and “stem” as used in the patent. The district court construed the term “fastening stem” to mean a “stem that attaches or joins other components.” Claim Construction Order at *9. On its face, that construction could plausibly cover a fastening stem that is present in a single-piece apparatus. As previously noted, one can envision a protrusion from the mounting cuff into the terminal cavity, even in a single-piece embodiment. To fall within the scope of the claims, however, that feature must constitute a “stem” and must perform a “fastening” function of some sort. The district court reasonably found that the plain language of
The same is true of the district court‘s construction of the phrase “a fastening stem that extends from the mounting cuff and into the second cavity of the terminal that receives the conductor.” Because claims 1 and 10 are not limited to a multi-piece apparatus, the fastening stem is not required to attach the mounting cuff to the terminal, and to that extent the district court‘s construction was incorrect. However, the remainder of the court‘s construction is consistent with the language of both the claims and the written description of the invention.
In summary, we vacate the judgment and the district court‘s constructions of “fastening stem” and “a fastening stem that extends from the mounting cuff and into the second cavity of the terminal that receives the conductor.” The district court should adjust the construction of those claim terms so as to allow for the independent claims to cover both single-piece and multi-piece embodiments, but the court‘s constructions should continue to give meaning to the terms “fastening” and “stem” in the context of the invention and the ordinary meaning of those terms.
No costs.
VACATED AND REMANDED