RA summary of the Federal Circuit decision, Festo v. Shoketsu Kinzoku Kogyo Kabushiki Co. Ltd.

US Court Decision (4) Festo2007 Summary

Festo2007 Summary

Yesterday, a majority panel (2-1) of the U.S. Court of Appeals for the Federal Circuit decided Festo v. Shoketsu Kinzoku Kogyo Kabushiki Co. Ltd. (also known as SMC Corporation), 05-1492 (Fed. Cir. 2007), addressing the question of whether an equivalent is foreseeable within the meaning the U.S. Supreme Court’s Festo decision. Festo, 535 U.S. 722 (2001).

Festo owns a patent on a magnetically coupled rodless cylinder. During prosecution, Festo amended its original independent claim to recite “a sleeve made of a magnetizable material,” and amended “sealing means” to indicate “a pair of sealing rings.” The purpose of the amendments was not explained, but was made for reasons related to patentability.

SMC’s accused device is also a magnetically coupled rodless cylinder, except that the sleeve is made of a non-magnetizable material (aluminum alloy), and SMC’s device contains only a single two-way sealing ring.

Festo argued that SMC’s device infringes under the doctrine of equivalents. SMC argued, among other things, that Festo was barred from invoking the doctrine of equivalents by the doctrine of prosecution history estoppel.

Prior Supreme Court and Federal Circuit cases have held that an amendment presumptively bars invocation of the doctrine of equivalents with three exceptions, one of those exceptions being that the equivalent was unforeseeable at the time of the amendment. (The other two exceptions are not relevant here).

This case thus presented two issues (1) “whether an ordinarily skilled artisan would have thought an aluminum sleeve to be an unforeseeable equivalent of a magnetizable sleeve in the context of the invention”; and (2) “whether a person of ordinary skill in the art would have considered the accused two-way sealing ring to be an unforeseeable equivalent of the recited pair of sealing rings.”

Festo proposed that the foreseeability test include consideration of a function/way/result element. Festo argued that the equivalent must have been foreseeable under the function/way/result test at the time of the amendment; i.e. there must have been knowledge that the equivalent would satisfy the function/way/result test. ^*1

The majority panel of the Federal Circuit disagreed:

We disagree that the foreseeability test requires application of the function/way/result or insubstantial differences test. Rather, we find that an alternative is foreseeable if it is disclosed in the pertinent prior art in the field of the invention. In other words, an alternative is foreseeable if it is known in the field of the invention as reflected in the claim scope before amendment.

Å@An equivalent is foreseeable if one skilled in the art would have known that the alternative existed in the field of art as defined by the original claim scope, even if the suitability of the alternative for the particular purposes defined by the amended claim scope were unknown.

The panel majority concluded that use of an aluminum alloy sleeve was foreseeable at the time of amendment because the pertinent prior art disclosed a non-magnetizable sleeve. “Festo could have claimed use of a non-magnetizable sleeve but did not do so. Accordingly, we find that the equivalent was surrendered by amendment.” ^*2

Judge Newman dissented:

The fact of whether technologic equivalency was known cannot be irrelevant to foreseeability, for the foreseeability bar is directed to subject matter that was foreseeably equivalent at the time of filing and amendment.

^*1Under Festo’s proposed interpretation of the foreseeability test: Festo argued that that use of an aluminum alloy sleeve was not foreseeable the date of amendment, because it was not known that an aluminum alloy sleeve would perform the magnetic shielding function. Festo also alleged that use of one sealing ring was not foreseeable because one would reasonably expect that a single sealing ring would result in deformation of the cylinder and that, therefore, the sealing function could not be performed by a single sealing ring.
^*2Because the panel majority concluded that the use of non-magnetizable sleeves was foreseeable under the original broader claim, the panel majority did not determine whether use of a single sealing ring was foreseeable.