Welker Bearing Co. v. PHD Inc. (Fed. Cir. 2008)

The full scope of an invention is most often conceptual in nature and is not limited to the particular examples or structural limitations provided in a patent application. Patent practitioners seeking the broadest possible protection for an invention will often draft claims describing the individual elements in terms of functional language to capture the full scope of the invention. In the past, it was common for claim drafters to use means/step-plus-function language to capture the full inventive concept or function of an otherwise structural element to avoid having a claim be misconstrued as limited to a few structural embodiments or examples. Congress enacted the predecessor to 35 U.S.C. §112, paragraph six, to expressly sanction means/step-plus-function language in a patent claim and to statutorily overrule the Supreme Court’s negative treatment of means-plus-function claiming in Halliburton Oil Well Cementing Co. v. Walker, 329 U.S. 1, 71 U.S.P.Q. 175 (1946), specifically with regard to the definiteness of these claims when means-plus-function language is employed at a point of novelty. See In re Donaldson Co., 16 F.3d 1189, 29 U.S.P.Q.2d 1845 (1994). However, over the years, §112, paragraph six, means-plus-function language has become interpreted by the courts as having very limited scope. Paragraph six of 35 U.S.C. §112 states as follows (emphasis added):

An element in a claim for a combination may be expressed as a means or step for performing a specified function without the recital of structure, material, or acts in support thereof, and such claim shall be construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof.

Accordingly, courts have consistently construed means-plus-function language in a claim as including only the corresponding material and structure appearing in the specification. See In re Donaldson Co., 29 U.S.P.Q.2d at 1849-50. Although the statute further states that the scope of means-plus-function language includes “and equivalents thereof,” this language has been interpreted narrowly to include only materials and structures performing an identical function that are equivalent to those disclosed in the specification and in existence at the time of filing. In addition, there remains great uncertainty over the relationship between statutory equivalence under §112, paragraph six, and the judicial doctrine of equivalence.

To avoid the narrow and uncertain treatment of means/step-plus-function claim language, many patent practitioners elect instead to become their own lexicographers and to describe elements broadly in the specification. However, when taking this approach, it is important that a draftsperson provide sufficient detail in the specification when describing the element, and choose terminology carefully to avoid having such claim terms be construed essentially as means-plus-function language that are interpreted narrowly under 35 U.S.C. §112, paragraph six. Even though a claim does not recite “means for,” a court may still determine that the element is described in functional terms, and thus falls within the ambit of 35 U.S.C. §112, paragraph six.

In Welker Bearing Co. v. PHD Inc., 550 F.3d 1090, 89 U.S.P.Q.2d 1289 (Fed. Cir. 2008), Welker Bearing had two patents issued, the ’478 patent and the ’254 patent, with identical specifications covering a pin clamp for holding a work piece securely in place during welding and other manufacturing processes. The pin clamp features an actuator for propelling and inserting a bullet-shaped locating pin into a hole of the work piece with clamping fingers that emerge out of the pin to securely hold the work piece firmly in place. The ’478 patent was the first to issue, claiming the pin assembly with “said assembly characterized by a mechanism for rotating in response to said rectilinear movement of said locating pin for moving said finger radially.” Thus, the claims explicitly required a rotational movement mechanism for extending and retracting the fingers. With the ’478 patent issued, Welker Bearing filed a continuation application that later issued as the ’254 patent with broader claims reciting that “said assembly characterized by a mechanism for moving said finger along a straight line into and out of said locating pin perpendicular to said axis A in response to said rectilinear movement of said locating pin.” Thus, the claims of the ’254 patent did not require rotational movement.

Thereafter, Welker Bearing sued PHD, Inc. in the District Court for the Eastern District of Virginia, accusing their “Clamp I” and “Clamp II” products of infringing their claims. Clamp I contained the rotational mechanism, but, after unsuccessful licensing negotiations, PHD designed Clamp II to exclude the rotational movement. Before the District Court, Welker Bearing conceded that Clamp II did not infringe the ’478 patent because it lacked the rotational mechanism for the clamping fingers. Thus, the inquiry by the Court was limited to whether Clamp I infringed the ’478 patent and whether Clamp II infringed the ’254 patent. With regard to the ’478 patent, the District Court determined that PHD had not infringed, since there were no infringing activities after the date of its issuance, and thus awarded summary judgment of noninfringement to the defendant.

With regard to the ’254 patent, however, the court construed the claim language “mechanism for moving said finger” as a means-plus-function limitation. As such, the court determined that the means-plus-function claim element should be limited to the corresponding structure provided in the specification. Since the only description provided for this element in the specification of the ’254 patent involved a rotational mechanism, the “mechanism for moving said finger” was limited to only rotational movement. Therefore, because the Clamp II device did operate by rotational movement, the District Court held on summary judgment that Clamp II did not infringe the claims of the ’254 patent.

Welker Bearing appealed, but the Federal Circuit affirmed the decision of the District Court in favor of PHD. In its opinion, the Federal Circuit cited M.I.T. v. Abacus Software, 462 F.3d 1344, 80 U.S.P.Q.2d 1225 (Fed. Cir. 2006) for guidance and authority on the issue. In that case, the court considered an appeal from a stipulated judgment of noninfringement concerning the proper claim construction of three terms appearing in the same claim of an allegedly infringed patent covering a color processing system. The three terms in question in M.I.T. were “scanner,” “aesthetic correction circuitry,” and “colorant selection mechanism.” In its opinion, the court stated that “Claims must be read in view of the specification, of which they are a part … Indeed, the specification is usually dispositive and is the single best guide to the meaning of a disputed term.” See M.I.T. 80 U.S.P.Q.2d at 1229 (citing Phillips v. AWH Corp., 415 F.3d 1303 (Fed. Cir. 2005)). With regard to the term “scanner,” the court concluded that the term was not defined in the specification. Thus, the court looked to several contemporaneous dictionaries around the time of filing as extrinsic evidence of the meaning the term. The court then affirmed the construction of the term “scanner” as requiring relative movement between the scanning element and the object to be scanned, and therefore held that the term “scanner” did not include a camera. The court further determined that the term “scanner” required close proximity, according to its ordinary and customary meaning to a person of ordinary skill in the art at the time of invention (i.e., its filing date) based on scanners that were in existence at the time of filing. Other extrinsic sources (e.g., dictionaries) did not instruct on this issue. See M.I.T. 80 U.S.P.Q.2d at 1230.

With regard to the term “colorant selection mechanism,” the appellants in M.I.T. argued that the District Court erred in construing this term as a means-plus-function element. However, the Federal Circuit affirmed the District Court’s conclusion. In its opinion, the Federal Circuit stated that “the phrase ‘colorant selection mechanism’ is presumptively not subject to §112, paragraph six because it does not contain the term ‘means.’ However, a limitation lacking the term ‘means’ may overcome the presumption against means-plus-function treatment if it is shown that ‘the claim term fails to recite sufficiently definite structure or else recites function without reciting sufficient structure for performing that function.’” See M.I.T. 80 U.S.P.Q.2d at 1231.

The Federal Circuit agreed that the presumption against finding means-plus-function claiming was overcome, and stated that “[t]he generic terms ‘mechanism,’ ‘means,’ ‘element,’ and ‘device,’ typically do not connote sufficiently definite structure [to avoid 112, 6].” See M.I.T. 80 U.S.P.Q.2d at 1231. The court in M.I.T. distinguished the term “digital detector” in Personalized Media Comm., LLC v. Int’l Trade Commission, 161 F.3d 696, 48 U.S.P.Q.2d 1880 (Fed. Cir. 1998) since the term “detector” in that case recited sufficient structure to avoid §112, paragraph six. However, the majority in M.I.T. stated that “a generic term like ‘mechanism’ can sometimes add sufficient structure to avoid 112, 6.” For example, in Greenberg v. Ethicon Endo-Surgery, Inc., 91 F.3d 1580, 39 U.S.P.Q.2d 1783 (Fed. Cir. 1996), the court held that §112, paragraph six did not apply to the term “detent mechanism” because the noun “detent” denotes a type of device with a generally understood meaning in the mechanical arts. Indeed, the court noted that many devices take their names from the functions they perform. However, the court distinguished Greenberg in stating that (1) the term “colorant selection” as a modification of the term “mechanism” was not defined in the specification, (2) there was no dictionary definition, and (3) there was no generally understood meaning in the art. Thus, the court concluded that “colorant selection mechanism” did not connote sufficient structure to a person of ordinary skill in the art to avoid §112, paragraph six treatment. Therefore, the term “colorant selection mechanism” was construed to only cover the “ink correction module (ICM)” embodiment described in the specification.

With regard to the term “aesthetic correction circuitry,” the appellants argued that the District Court erred in holding that the presumption against §112, paragraph six treatment was overcome. On appeal, the Federal Circuit agreed with the appellants. The court reasoned that “[i]n contrast to the term ‘mechanism,’ dictionary definitions establish that the term ‘circuitry,’ by itself, connotes structure,” giving particular weight to contemporaneous technical dictionaries. The court cited two prior cases in support of its conclusion that the term “circuit” coupled with a description of its function (e.g., its operation or other identifier) generally connotes sufficient structure to avoid §112, paragraph six. See Linear Tech. Corp. v. Impala Linear Corp., 379 F.3d 1311, 72 U.S.P.Q.2d 1065 (Fed. Cir. 2004); and Apex Inc. v. Raritan Computer, Inc., 325 F.3d 1364, 66 U.S.P.Q.2d 1444 (Fed. Cir. 2003). The court then concluded that the term “circuitry” “does not merely describe a circuit; it adds further structure by describing the operation of the circuit.” See M.I.T. 80 USPQ2d at 1232. The court then decided to leave it to the District Court to define the term “aesthetic correction circuitry” with greater particularity on remand.

In the dissenting opinion, Chief Judge Michel took issue with the majority in M.I.T. in its construction of the term “aesthetic correction circuitry.” The dissenting opinion distinguished both the Apex and Linear cases, in that the term “circuit” in those cases was further qualified by an appropriate identifier that had at least some additional connotation or suggestion of structure to one of ordinary skill in the art according to technical dictionaries or as evidenced by expert testimony. The dissent argued that not any “adjectival qualification (A.Q.)” connotes sufficient structure for the term “circuit” to avoid §112, paragraph six, but rather only an “appropriate A.Q.” as demonstrated by technical dictionaries or other evidence will suffice. The dissent further argues that “aesthetic correction” is not an “appropriate A.Q.,” to connote sufficient structure to the term “circuitry.” Rather, the dissent concludes that “aesthetic correction” is solely functional language that provides no further suggestion about the structure or operation of the circuit. Accordingly, the dissent argues that the term “aesthetic correction circuitry” should have been construed as a means-plus-function element under §112, paragraph six.

In view of these precedents, including M.I.T., the Federal Circuit in Welker Bearing concluded that the term “mechanism for moving said finger” was properly construed by the District Court as a means-plus-function element under §112, paragraph six. Since this element was construed as covering only the corresponding structure in the specification of a “rotating central post,” the court affirmed the District Court’s summary judgment ruling of non-infringement. The court reasoned that the term “mechanism for moving said finger” includes even less structure than “colorant selection mechanism” in M.I.T., and no adjective endows the claimed “mechanism” with a physical or structural component. Furthermore, the Court further reasoned that the claim in which the element appears provides no structural context for determining the characteristics of the “mechanism” other than to describe its function. Thus, “the unadorned term ‘mechanism’ is simply a nonce word or a verbal construct that is not recognized as the name of structure and is simply a substitute for the term ‘means for.’” See Welker Bearing 89 U.S.P.Q.2d at 1294. Interestingly, the court in Welker, Bearing provides some guidance for how the applicant could have avoided the outcome in this case:

The applicant for the ’254 patent could have supplied structural context to claim 1 in any number of ways. If claim 1 of the ’254 patent had recited, e.g., a “finger displacement mechanism,” a “lateral projection/retraction mechanism,” or even a “clamping finger actuator,” this court could have inquired beyond the vague term “mechanism” to discern the understanding of one of skill in the art. If that artisan would have understood such language to include a structural component, this court’s analysis may well have turned out differently. Instead the applicant chose to express this claim element as “a means or step for performing a specified function without the recital of structure, material, or acts in support thereof.” 35 U.S.C. §112 6. Therefore, this court must agree with the district court, which properly applied means-plus-function treatment to this term.

See Welker Bearing 89, U.S.P.Q.2d at 1294 (emphasis added).

Finally, Welker Bearing argued that Clamp II would infringe the ’254 patent under the doctrine of equivalents, if not literal infringement. The court rejected this argument in stating that “[t]his case presents only the question of structural equivalents under §112, 6” and that the judicial doctrine of equivalents does not apply because the asserted linear movement equivalent was in existence at the time of filing. Although “[s]tructural equivalents [under §112, 6] and the doctrine of equivalents are closely related” with both based on “similar analyses of ‘insubstantiality of the differences,’” the court in Welker  Bearing stated that “where, as here, a proposed equivalent has arisen before patent issuance, a §112, 6 structural equivalents analysis applies and any analysis for equivalent structure under the doctrine of equivalents collapses into the §112, 6 analysis.” See Welker Bearing, 89 U.S.P.Q.2d at 1296. The court then concluded that the linear moving Clamp II design was not an equivalent under §112, paragraph six, since there was evidence that the linear moving alternatives were considered by the inventor and rejected in favor of the rotating central post, which undermined any assertion of “insubstantial” differences between the two approaches.

As Welker Bearing and M.I.T., as well as the cases cited therein, clearly demonstrate, when a patent practitioner or applicant attempts to draft a patent application to cover the full scope of an invention, including the lexicographic creation of a structural element in terms of its function, it is important that any coined terms be selected carefully to connote sufficient structure according to an ordinarily skilled artisan, so that the element will not be construed narrowly by the Patent Office or later by a court of law as a means-plus-function element under §112, paragraph six. Indeed, it would be wise for an applicant or practitioner to consult current dictionaries and technical resources in choosing these terms to balance the sufficient connotation of structure without unduly limiting the scope of the claims. In addition to choosing sufficiently “structural” claim element terms, an applicant or practitioner should also fully define the element term in the specification as fully as possible, including hierarchical layers of description from a fully functional description to groupings of structure and function, and then specific examples under each grouping, providing a representative number of species to support the full genus of the claim element term. Such layers of descriptiveness for a term may be recited in a series of dependent claims to provide a path of retreat in case of limited claim construction or invalidity of the broader claims. Such an approach should also provide a dual benefit of not only avoiding the narrow §112, paragraph six treatment of the claim element, but also help to ensure that such claim element is definite under 35 U.S.C. §112, second paragraph, and fully supported and enabled under 35 U.S.C. §112, first paragraph.

Failure to define claim element terms with sufficient structural connotation and description of the claim element in the specification can lead to drastic results, such as a finding of non-infringement and possible invalidity due to indefiniteness. Cf. Aristocrat Technologies v. Int’l Game Tech., 521 F.3d 1328, 86 U.S.P.Q.2d 1235 (Fed. Cir. 2008); Blackboard Inc. v. Desire2Learn Inc., 91 U.S.P.Q.2d 1481 (Fed. Cir. 2009), and cases cited therein. However, when “fleshing out” the description and examples for such claim elements in the specification, the applicant or practitioner should be cautioned against going too far and possibly facilitating an obviousness rejection by suggesting equivalency of examples in the prior art.

Practice Tip:

When acting as a lexicographer in drafting broad claim elements, the draftsperson should carefully select claim element terms that suggest sufficient structure and provide a sufficiently detailed definition of the term in the specification to avoid narrow treatment under § 112, paragraph six.