1. A safety razor blade unit comprising a guard, a cap, and a group of first, second, and third blades with parallel sharpened edges located between the guard and cap, the first blade defining a blade edge nearest the guard having a negative exposure not less than -0.2 mm, and the third blade defining a blade edge nearest the cap having a positive exposure of not greater than +0.2 mm, said second blade defining a blade edge having an exposure not less than the exposure of the first blade and not greater than the exposure of the third blade.

The district court counted three blades, said 3 ≠ 4; no infringement. The majority of the CAFC (04-1220) said: not so fast with the math.

On germane claim construction case law -

“In construing claims, the analytical focus must begin and remain centered on the language of the claims themselves, for it is that language that the patentee chose to use to particularly point out and distinctly claim the subject matter which the patentee regards as his invention.” Interactive Gift Express, Inc. v. Compuserve, Inc., 256 F.3d 1323, 1331 (Fed. Cir. 2001) (quoting 35 U.S.C. § 112, ¶ 2); see also SRI Int’l v. Matsushita Elec. Corp., 775 F.2d 1107, 1121 n.14 (Fed. Cir. 1985) (en banc) (“Specifications teach. Claims claim.”).

Claim construction requires this court to place the claim language in its proper technological and temporal context. The best tools for this enterprise are the various forms of intrinsic evidence and, when appropriate, extrinsic evidence. See Vitronics, Corp. v. Conceptronic, Inc., 90 F.3d 1576, 1582 (Fed. Cir. 1996). The intrinsic evidence, “i.e., the patent itself, including the claims, the specification and, if in evidence, the prosecution history . . . is the most significant source of the legally operative meaning of disputed claim language.” Id. (internal citation omitted); see also United States v. Adams, 383 U.S. 39, 49 (1966) (“[I]t is fundamental that claims are to be construed in the light of the specifications and both are to be read with a view to ascertaining the invention.”); Astrazeneca v. Mutual Pharm. Co., Inc., 384 F.3d 1333, 1336-37 (Fed. Cir. 2004) (“[E]vidence intrinsic to the patent – particularly the patent’s specification, including the inventors’ statutorily-required written description of the invention – is the primary source for determining claim meaning.” (citing Bell Atl. Network Servs., Inc. v. Covad Communications Group, Inc., 262 F.3d 1258, 1268 (Fed. Cir. 2001); Vitronics, 90 F.3d at 1582)).

Specifically on the blades -

The ’777 patent claims a disposable safety razor with a group of blades, each blade placed in a particular geometric position relative to the other blades of the group. Prior art razors with multiple blades shaved closer to the skin than two-bladed razors but had “a serious detrimental influence on other blade unit characteristics, most notably the drag forces experienced when the blade unit is moved over the skin, with the consequence that the overall performance of the blade unit [was] markedly inferior [compared to two-bladed razors] despite a closer shave being obtained.” ’777 patent, col. 1, ll. 24-29.

The inventive contributions of the ’777 patent are varying progressively the exposure and spacing parameters of the blades to overcome the undesired drag forces produced by razors with multiple blades, not simply limiting the number of blades to three.

As to interpreting the scope of the claim -

As explained below, this court discerns that claim 1 uses the “open” claim terms “comprising” and “group of,” in addition to other language, to encompass subject matter beyond a razor with only three blades. Moreover, the specification’s focus on blade exposures and express reference to “blade units with a plurality of blades,” ’777 patent, col. 1, ll. 3-6, shows as well that this invention covers razors with more than three blades.

The claim uses two terms to show this open-ended meaning. The word “comprising” transitioning from the preamble to the body signals that the entire claim is presumptively open-ended. Crystal Semiconductor Corp. v. TriTech Microelectronics Int’l, Inc., 246 F.3d 1336, 1347 (Fed. Cir. 2001); Innovad Inc. v. Microsoft Corp., 260 F.3d 1326, 1333 (Fed. Cir. 2001).

The addition of elements not recited in the claim cannot defeat infringement. See Crystal Semiconductor, 246 F.3d at 1348 (“[T]he transition ‘comprising’ creates a presumption that the recited elements are only a part of the device, that the claim does not exclude additional, unrecited elements. KCJ Corp. v. Kinetic Concepts, Inc., 223 F.3d 1351, 1356 (Fed. Cir. 2002).”).

The claim element identifying the blades likewise uses another presumptively “open” claim term – “group of.” ’777 patent, col. 4, l. 6. At the outset, the language “group of” does not place any limits or closed implications on the elements following this broad designation. Claim drafters often use the term “group of” to signal a Markush group. A Markush group lists specified alternatives in a patent claim, typically in the form: a member selected from the group consisting of A, B, and C. See Manual of Patent Examining Procedure § 803.2 (2004). A Markush group by its nature is closed. If an applicant tries to claim a Markush group without the word “consisting,” the PTO will insist upon the addition of this word to ensure a closed meaning. Thus, in order to “close” a Markush group, the PTO insists on the transition phrase “group consisting of.” See Abbott Labs. v. Baxter Pharm. Prods., Inc., 334 F.3d 1274, 1280 (Fed. Cir. 2003). Without the word “consisting” the simple phrase “group of” is presumptively open.

Skating back to the blades -

If intending to limit the claimed invention to a three-bladed razor, the patent drafter would not have used the words “group of.” Rather, the drafter would have used the words “group consisting of,” or the simple formulation “and first, second, and third blades.” Because the drafter chose to use the open term “group of,” additional members in the element “group of . . . blades” will not defeat infringement. In other words, a razor with two “second blades,” as in the [Energizer] QUATTRO®, will still fall within the literal language of the claim.

The accused QUATTRO® device, in fact, has two “second blades” because both of the middle blades in the accused device meet the definition of the “second blade” set forth in the claim. Any subset of three blades in a blade unit meeting these definitions is a “group of blades” as defined by the clear language of the claim. This claim is not ambiguous. In fact, the patentee underscored this open-ended claim meaning by using both the open-ended transition phrase “comprising” for all elements of claim 1 as discussed above, and the open-ended claim term “group of” for each part of this element.

Senior Circuit Judge Archer had a dissenting opinion, generally supporting the majority opinion on the legal logic, but still finding 3 ≠ 4 in a different reading of the specification and other circumstantial evidence. Majority opinion was to vacate the district court ruling and remand for another round.