Federal Circuit Finds “Mechanism for Moving” to be Means plus Function Term

In Welker Bearing Company v. PHD, Inc., Case 2008-1169 (Fed. Cir. Dec. 15, 2008), the Welker Bearing Company (Welker) owns U.S. Patents 6,786,478 (‘478 patent), which issued on September 7, 2004, and 6,913,254 (‘254 Patent), which issued on July 5, 2005.  The ‘254 and ‘478 patents, which have identical specifications, are directed towards locating and clamping assemblies for use during welding, with both claiming pin clamps to securely hold an item while being worked upon or welded.  The pin clamps are topped with a locating pin inserted into holes in the item and clamping fingers extending from the pin clamp to secure the item to an annular ring on the pin clamp.

Claim 1 of the ‘478 patent contains 5 clauses directed towards locating an clamping assembly, with the fifth clause reciting “said assembly characterized by a mechanism for rotating in response to said rectilinear movement of said locating pin for moving said finger radially.”  The Federal Circuit states that Welker, with the PTO allowing the claims of the ‘478 patent to issue without any note of rotational movement as a required limitation for allowance of the ‘478 patent, felt invited to file a continuation application having broader claims.  The continuation application issued as the ‘254 patent. As such, claim 1 of the ‘254 patent recites “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.”

Welker filed suit in the Eastern District of Michigan claiming that the PHD devices, Clamp I and Clamp II, infringed Welker’s ‘478 and ‘254 patents.  However, Welker conceded to the District Court that PHD’s Clamp II does not infringe the ‘478 patent because the Clamp II does not have a rotational mechanism for the clamping fingers.  As such, the District Court only looked into Clamp I’s infringement of the ‘478 patent and Clamp II’s infringement of the ‘254 patent.

The District Court construed the language of claim 1 of the ‘254 patent, wherein it stated “mechanism for moving said finger,” to be a means-plus-function limitation, and consequently, requiring a structure in the specification to correspond to the functional language.  The only such structure found in the specification was the rotating central post to move the finger in and out of the locating pin, found at Col. 6 of the written description of the ‘254 patent.  The District Court found that the record did not show that the Clamp I device was made, used, sold or offered for sale by PHD after the ‘478 patent was issued and thus granted summary judgment of noninfringement.  With respect to the ‘254 patent, the District Court granted summary judgment of noninfringement because PHD’s Clamp II did not have a rotating central post.  Welker appealed both decisions in the Federal Circuit.

The Federal Circuit, in affirming the District Court’s decision regarding the ‘478 patent, stated that the record did not show that PHD conducted any activity that infringed the ‘478 patent after the ‘478 patent was issued.  Prototypes of the Clamp I were made and given to General Motors (GM) in late 2003 or early 2004, but were never produced or used commercially.  The ‘478 patent issued on September 7, 2004.  The record also contained no evidence showing PHD sold any of the Clamp I units to GM after this date or even continued to offer the Clamp I unit for sale after the issuance date.   Welker asserted that PHD “had an affirmative duty at the point in time the patent issued to take the product off the market,” however, the Federal Circuit stated that “PHD did not have any burden to prove it retracted any putative offer for sale,” because “the burden remains with the patentee to prove infringement, not on the defendant to disprove it.”   Thus, the Federal Circuit upheld the District Court ruling finding noninfringement of the ‘478 patent.

Additionally, as the ‘254 patent issued nearly 10 months after the ‘478 patent, the Federal Circuit found that Clamp I cannot infringe the ‘254 patent for the same reasons Clamp I does not infringe the ‘478 patent.

With respect to the ‘254 patent and Clamp II, the Federal Circuit reviewed the District Court’s construal of “mechanism for moving said finger” as being a means-plus-function limitation of claim 1.    The Federal Circuit noted that they have “consistently held that “[m]eans-plus-function claiming applies only to purely functional limitations that do not provide the structure that performs the recited function.” Phillips v. AWH Corp., 415 F.3d at 1311 (Fed. Cir. 2005).  Moreover, the Federal Circuit noted that “a patentee’s use of the word ‘means’ in a claim limitation creates a presumption that 35 U.S.C. §112 paragraph 6 applies. TriMed, Inc. v. Stryker Corp., 514 F.3d 1256, 1259 (Fed. Cir. 2008).”

The Federal Circuit noted that, while the ‘254 patent claim language uses the word “mechanism” rather than “means,” 35 U.S.C. 112 paragraph 6 can also apply for the “generic terms ‘mechanism,’ ‘means,’ ‘element,’ and ‘device,’ [which] typically do not connote sufficiently definite structure,” and that “[t]he term ‘mechanism’ standing alone connotes no more structure than the term ‘means.’,” citing Massachusetts Institute of Technology v. Abacus Software, 462 F.3d 1344, 1354 (Fed. Cir. 2006).  On the other hand, the Federal Circuit noted that in Greenberg v. Ethicon Endo-Surgery, Inc., 91 F.3d 1580 (Fed. Cir. 1996), where “mechanism” was preceded by the word “detent,” they examined several definitions of ‘detent’ and stated that “[b]ecause these definitions connoted adequate structure that was reasonably well understood in the art, this court concluded that ‘detent mechanism’ was not a mere functional placeholder.”

In applying the above case law to determining the meaning of “mechanism for moving said finger,” the Federal Circuit stated that “[n]o adjective endows the claimed “mechanism” with a physical or structural component.  Further, claim 1 provides no structural context for determining the characteristics of the “mechanism” other than to describe its function…one of skill in the art would have no recourse but to turn to the ‘254 patent’s specification to derive the structural connotation for the generically claimed “mechanism for moving said finger.”   Consequently, the Federal Circuit found that the District Court was correct in applying the means-plus-function treatment to the noted term of claim 1 of the ‘254 patent.

Next, the Federal Circuit reviewed the District Court’s determination of “the corresponding structure, material, or acts described in the specification and equivalents thereof.”  35 U.S.C. §112, Par. 6.  The Federal Circuit noted that, when making such a determination, “a court may not import functional limitations that are not recited in the claim, or structural limitations from the written description that are unnecessary to perform the claimed function.” Wenger Mfg., Inc. v. Coating Mach. Sys., Inc., 293 F.3d 1225, 1233 (Fed. Cir. 2001).  The District Court adopted the construction of “mechanism for moving” as proffered by PHD, and which included a “rotating central post.”  Welker argues that such construction is wrong because the specification teaches that a “rotating central post” isn’t necessary for the function of “moving said finger along a straight line…”  However, the Federal Circuit stated that the specification of the ‘254 patent supports the District Court’s analysis because “[t]he specification repeatedly identifies a rotating central post as the disclosed structure for performing the claimed function of “moving said finger…”,” and such is shown in Fig. 7 of the ‘254 patent.

The Federal Circuit went on to say that other claim construction doctrines, including claim differentiation, ordinary meaning and clear disavowal of claim scope do not change the construction of the noted claim element.  As per claim differentiation, with respect to claim 1 of the ‘478 patent reciting a rotating element and claim 1 of the ‘254 patent, which doesn’t recite a rotating element, the Federal Circuit stated that “[t]his difference between claims in different patents does not change the meaning of these means-plus-function limitations…Because both terms share the same specification with the same structure corresponding to the claimed function, this court cannot give these terms any different scope.”  As such, the Federal Circuit upheld the District Court’s determination of the corresponding structure of the means-plus-function claim.

In reviewing the District Court’s analysis of the infringement of the means-plus-function claim, the Federal Circuit noted that “[l]iteral infringement…“requires that the relevant structure in the accused device perform the identical function recited in the claim and be identical or equivalent to the corresponding structure in the specification.”  Applied Med. Research Corp. v. United States Surgical Corp., 448 F.3d 1324, 1333 (Fed. Cir. 2006).”  However, the only embodiment of the structure involved a rotating central post, and “[n]othing in the specification suggests any other structure for moving the claimed fingers.”  While literal infringement of a means plus function limitation requires analyzing the disclosed structure and equivalents thereof, the Federal Circuit found that “Welker Bearing effectively concedes” that the two structures are not equivalent “by arguing that ‘once claim 1 of the ‘254 patent is construed as not requiring any rotating mechanism, PHD’s Clamp II reads on claim 1 of the ‘254 patent . . . .'”  Consequently, PHD’s Clamp II, which moves the clamping fingers using a mechanism that moves linearly, is found to not literally infringe on Welker’s claim the scope of which is limited to a structure which moves the clamping fingers with a rotating central post or equivalents thereof.

The Federal Circuit goes on to reject Welker’s argument that PHD’s Clamp II might infringe under the doctrine of equivalents, because the case does not present a doctrine of equivalents issue.  Specifically, under the given facts, only a structural equivalents issue under §112 par. 6 arises.  Though the inquiries under the two doctrines are similar as per analyzing the insubstantiality of differences between a disclosed structure and an accused infringing structure, the two doctrines differ as per the timing of the accused infringing structure.  For structural equivalents under §112 par. 6, the equivalent structure “must have been available at the time of the issuance of the claim,” while a “technology developed after the issuance of the patent,” can fall under the doctrine of equivalents.  Al-Site Corp. v. VSI Int’l, Inc., 174 F.3d 1308, 1320 (Fed. Cir. 1999).  Because PHD’s Clamp II mechanism for driving the finger movement was well know in the art at the time of the invention, the Federal Circuit stated that “it cannot be classified as an after-arising technology” and is only available for equivalency analysis under §112 par. 6. Thus, no doctrine of equivalents analysis is performed and the §112 par. 6 findings arise and subsume a doctrine of equivalents analysis with regard to existing equivalencies.  Under such analysis, the Federal Circuit agreed with the District Court ruling in granting summary judgment of noninfringement of the ‘254 patent.

In summary, the Federal Circuit affirmed the District Courts rulings of summary judgment, in favor of PHD, on noninfringement for both the ‘254 and ‘478 patents.

Significance to Patent Applicants

Welker Bearing presents a reminder that, in order to avoid the limitations of 35 U.S.C. §112, par. 6, applicants cannot merely replace the word “means” with a generic term.  Instead, applicants need to include sufficient structure to describe the generic term, thereby adding structural features, or simply use structural terms such as “circuit” which have a defined (albeit broad) meaning.  Moreover, in order to guard against narrow interpretations, applicants need to ensure that the specification includes alternate examples of how a mechanism can be achieved.  Of significance in Welker Bearing was the lack of an example other than the rotating post on which the patent owner could rely to find another structure in the specification supporting the recited means for moving.


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