On rеmand from this court, the United States District Court for the District of Minnesota granted summary judgment that White Consolidated Industries, Inc. does not infringe The Toro Company’s United States Patent No. 4,694,528 (the '528 patent) under the doctrine of equivalеnts (DOE). Because the district court’s summary judgment was improper, this court vacates the judgment and remands for trial.
I.
Toro owns the '528 patent which discloses and claims a “convertible vacuum-blower.” Vacuum-blowers are handheld machines used to vacuum leaves and small debris, or to disperse the same in the blower mode. As described in detail in this .court’s previous opinion, the '528 patent discloses a vacuum-blower design with a removablе cover to which is attached a restriction ring.
Toro Co. v. White Consol. Indus., Inc.,
16. A convertible vacuum-blower comprising:
[1] a housing having an air inlet and an air outlet;
[2] a motor supported in said housing;
[3] an impeller having a plurality of impeller blades supported for rotary motion in said housing, in fluid communication with said air inlet and said air outlet, and rotatably driven by said motor;
[4] a removable air inlet cover for covering said air inlet, said air inlet cover having apertures for passage of air through the cover;
[5] attachment means for removably securing said air inlet cover to said housing; and
[6] said cover including means for increasing the pressure developed by said vacuum-blower* during operation as a blоwer when air is being supplied to said impeller through said apertured cover.
(Emphasis added.)
In 1998, Toro filed suit against White alleging infringement of claims 16 and 17 of the '528 patent. The district court construed claims 16 and 17 and granted Toro’s motion fоr summary judgment holding that White literally infringed these claims. On appeal, this court interpreted the claim. This court construed clause [6] of claim 16 to mean that the restriction ring, or “means for increasing the pressure,” is “permanently affixed to and included as part of the cover.”
Toro I,
On remand, the district court interpreted Toro I as holding that “a critical function of the air inlet cover claimed in the '528 patent is to automatically insert and remove the restriction ring.” Toro Co. v. White Consol. Indus., Civil No. 4-95-656, slip op. at 9 (D.Minn. Aug.9, 2000) (Toro II). The air inlet cover of White’s accused vacuum-blower is not attached to the restriction ring and, thus, does not automatically place the ring. The district court, therefore, granted summary judgment that White’s accused vacuum-blowers do not infringe the '528 patent under the doctrine of equivalents. The district court further determined that this court’s statement that material facts regarding equivalency were in dispute was merely dicta and that this court’s remand instruction was “merely [ ] a shorthand signal that the issue of equivalency was not yet ripe for appellate adjudicаtion.” Toro II, slip op. at 13. Toro appeals. This court has jurisdiction under 28 U.S.C. § 1295(a)(1).
II.
This court reviews without deference a district court’s grant of summary judgment and draws all reasonable factual inferences in favor of the non-movant.
Anderson v. Liberty Lobby, Inc.,
To infringe a claim under the doctrine of equivalents, an accused device must include an equivalent for each literally absent claim limitation.
Dawn Equip. Co. v. Kentucky Farms,
[Cjourts have [ ] recognized that to permit imitation of a patented invention which does not copy еvery literal detail would be to convert the protection of the patent grant into a hollow and useless thing. Such a limitation would leave room for — indeed encourage — the unscrupulous copyist to makе unimportant and insubstantial changes and substitutions in the patent which, though adding nothing, would be enough to take the copied matter outside the claim, and hence outside the reach of law.
Graver Tank & Mfg. Co. v. Linde Air Prods. Co.,
In some cases, the change in the accused devicе is so facially “unimportant and insubstantial” that little additional guidance is needed for a fact finder to determine whether an accused device includes an equivalent of a claim limitation. For example, if аn accused infringer has simply separated into two components what the patentee has claimed as one component, a fact finder might indeed find such a change “insubstantial.”
Dolly, Inc. v. Spalding & Evenflo Cos.,
In appropriate cases the function-way-result test offers additional guidance on the question of equivalence.
Dawn Equip.,
Clause [4] of claim 16 recites the objective of the cover as covering the air inlet of the vacuum-blower (to keep fingers and clothes from entering the impeller) and permitting the passage of air through the cover to the inlet. The written description of the '528 patent explains that the unitary cover and ring design “is also advantageous in that it automatically restricts the sizе of air inlet 26 depending upon which operation is being conducted without having the operator manually insert or remove a replaceable ring.” Col. 7, II. 6-12. In
Toro I,
this court used this description, along with the figures in the speсification, to help enlighten the meaning of “said cover including [a restriction ring].” This court concluded that “the restriction ring is ‘part of the cover, in permanent attachment.”
Toro I,
In this case, the structural limitation was a unitary cover and ring. The primary function or objective of the cover, as described in the specification and recited in claim 16, is to cover the air inlet of the vacuum-blower (to keep fingers and clothes from entering the impeller) and permit the passage of air. While this structure could have a variety of other functions (as is often the case with structures), including supрorting surrounding structures, attaching related parts, and so forth, these functions do not become part of the claimed structure unless claimed as such. The function of automatic placement of the ring in the claimed unitary cover and ring is inherent in that structure, much as supporting surrounding structures are inherent in a structural limitation. In fact, Toro’s expert, Mr. Fitz-Gibbon, testified that automatic placement is inherent in this unitary structure.
In
Vehicular,
this court specifically addressed a similar question. In that case, this court explained: “[A]n accused device could conceivably lack an insignificant function of a single claim limitation and still be only insubstantially different than the clаimed invention.”
Vehicular,
Neither the '528 patent’s specification nor this court’s claim interpretation, however, make the inherent function of automatic placement a key objective of this invention. Rather, the specification mentions in passing the automatic placement feature among other functions of the cover. Thus, on this record, a genuine issue of material fact remains as to whether White’s vacuum-blower cover рerforms substantially the same overall function as the cover claimed by the '528 patent. In light of the understanding enunciated by this court that automatic placement is a non-eritical inherent function of the claimed cover, a reasonable jury could find White’s two-piece structure equivalent to the one-piece structure recited in the asserted claims.
CONCLUSION
The district court improperly granted summary judgment that White’s vacuum-blower does not infringe claims 16 and 17 of the '528 patent under the doctrine of equivalents.
COSTS
Each party shall bear its own costs.
VACATED and REMANDED.