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Limited Disclosure Supports Means-Plus-Function Limitation

March 15, 2002
Tridico Ph.D., Anthony C.

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Last Month at the Federal Circuit - April 2002

Judges: Clevenger (author), Rader, and Bryson

In Baker Hughes, Inc. v. Davis-Lynch, Inc., No. 01-1377 (Fed. Cir. Mar. 15, 2002) (nonprecedential decision), the Federal Circuit affirmed a district court’s grant of SJ for Baker Hughes, Inc. (“Baker”) that the claims of U.S. Patent No. 4,311,314 (“the ‘314 patent”) were not indefinite. The Court vacated, however, the district court’s order granting SJ as to the obviousness and on-sale bar defenses of Davis-Lynch, Inc. (“Davis”), remanding these issues for trial.

The ‘314 patent discloses and claims an inflatable packer for use in the drilling of oil and gas wells. The inflatable packer seals off the surrounding borehole from a pipe, known as a “mandrel,” and thus isolates the pipe from the surrounding earth. Conventional inflatable packers had a tendency to catch on the walls of the borehole, tearing them away and destroying their utility. The ‘314 patent claims an inflatable packer with a grit-like substance bonded to the outer surface of the mandrel, making it more likely that the packer will be pulled down with the mandrel rather than catching on a wall, thus reducing the risk of tearing.

The ‘314 patent was filed on November 20, 1980, and was initially assigned to Completion Tool Company (“CTC”). CTC was acquired by Baker in 1995 and Baker subsequently sued Davis for infringement of the ‘314 patent. Davis moved for SJ of invalidity based on obviousness, indefiniteness, and the on-sale bar. Baker cross-moved for SJ on the indefiniteness and on-sale bar issues, but not on obviousness, and also moved for partial SJ of infringement. The lower court granted Baker’s motions as to indefiniteness, the on-sale bar, and infringement, and denied Davis’s motions on invalidity. The lower court’s order was unclear, and the parties disputed whether SJ was granted for Baker as to obviousness.

The Federal Circuit agreed with the district court’s ruling that claim 1 of the ‘314 patent was not indefinite. At issue was the means-plus-function limitation that recites “a means to inflate.” According to the Federal Circuit, the district court correctly noted that the port described in the specification is not sufficient structure in and of itself to accomplish the function of inflating the sleeve, as required by the claim. However, repeated references in the specification and claims to an inflatable packer inform one of ordinary skill in the art of the necessary accompanying structure to carry out the inflation means.

As to obviousness, the Court concluded that both documentary evidence and expert testimony existed for the proposition that the use of “grit-like” material was known in the inflatable packer field, and while the evidence may not conclusively establish the obviousness of the ‘314 claims, it does suffice to raise a triable issue of material fact. Thus, the Federal Circuit vacated the lower court’s grant of SJ of nonobviousness and remanded for trial.

The Federal Circuit also vacated and remanded for trial the lower court’s grant of SJ as to the on-sale bar. The district court had found that the evidence did not tend to show that the complete invention was on-sale prior to the critical date since the documentary evidence did not indicate whether the products sold were packers and the affidavits were insufficiently corroborated. The Federal Circuit disagreed, explaining that, contrary to the district court’s opinion, the case law does not limit the application of the on-sale bar to the use, sale, or offer for sale of a complete invention. According to the Federal Circuit, the on-sale bar is triggered by the use, sale, or offer for sale of subject matter which fully anticipated the claimed invention or would have rendered the claimed invention obvious by its addition to the prior art. Further, in regard to the district court’s rationale for limiting the weight assigned to the affidavits, oral corroboration is evaluated for a number of factors, including the extent, details, and contradiction or impeachment of the witnesses’ testimony. Thus, the Federal Circuit concluded that when all the pertinent evidence is considered, Davis had offered sufficient, corroborated evidence to create a triable issue of material fact as to whether the ‘314 patent is invalid due to an on-sale bar.