Construing Patent Claim Preambles: Understanding "Life, Meaning and Vitality"
 
May 13, 2003
 
Michael Colitz - Tampa

Patent claims are the most critical component of any patent application.  These single-sentence legal descriptions serve to define the metes and bounds of the intellectual property.  However, the language within a claim is always open to interpretation.  For this reason, courts typically interpret, or construe, patent claims in order to determine both their meaning and scope.  One source of continual debate among patent litigants is whether the introductory portion of a claim, known as the preamble, should be construed as limiting the scope of the claim, or whether it just defines a nonlimiting purpose of the invention.  The absence of any easily applied rules for construing preambles means that the debate is sure to continue.

The preamble is just one of three parts in a typical patent claim, with the remaining parts being the transition and body.  The transition links the preamble to the body of the claim and indicates whether the claim is opened or closed.  Opened claims, signified by the transition “comprising,” are infringed if a competing device has at least all of the recited claim elements.  Closed claims, signified by the transition “consisting of,” are only infringed if the competing device has no more or less than all the recited elements. 

The body comes after the transition and lists the various elements that form the structures, steps or parts of the claimed invention.  The elements listed in the body undisputedly limit the scope of the claim.  By contrast, the preamble is typically used as a means of broadly defining the invention and is similar to the title of the invention.  Accordingly, the preamble is often used by the Patent & Trademark Office in assigning patent applications to a particular examining art unit and in classifying the invention.  Nonetheless, similar to the body, the preamble can recite structures, steps and parts that limit the overall scope of the claim.

Whether elements recited in a preamble should be construed as limiting the scope of the claim is an issue the U.S. Court of Appeals for the Federal Circuit (CAFC) has visited on numerous occasions.  Most patent litigators are familiar with the various tests for construing claim preambles.   The most frequently quoted CAFC test requires a limiting construction for the preamble if it is “necessary to give life, meaning, and vitality” to the claim. ¹  The CAFC has also noted that “when the claim drafter chooses to use both the preamble and the body to define the subject matter of the claimed invention, the invention so defined, and not some other, is the one the patent protects.”²  Conversely if the “body of the claim sets out the complete invention,” then the language of the preamble is “superfluous.” ³ In practice, these statements do little to aid in claim construction and merely serve to frame the ultimate issue: when does the preamble serve to limit the invention?

An analysis of one recent CAFC decision helps shed light on the proper manner of construing preambles.  In Eaton Corp. v. Rockwell Int’l, 2003 WL 1562153 (Fed. Cir. 2003), the CAFC considered a district court’s interpretation of a claim on a vehicular transmission shift control system.  The claim at issue was a method claim that contained a lengthy preamble reciting various structural elements of the vehicle driveline system.  The preamble also contained numerals referencing the portions of the specification and drawings that more fully described the driveline.  Eaton, the patent owner, argued that the structures in the preamble did not limit the claim,  and that the invention was merely defined by the two steps recited in the body. 

The first step recited “retaining said vehicle master clutch (8) engaged during the gear ratio shift in said drive train.”  The second step recited “urging said first and second members of said first clutch into a disengaged condition.”  In each step, those structures introduced by “said” were first described in the preamble of the claim.  Thus, each claim element relied upon the preamble for antecedent basis.  The district court interpreted the preamble as not limiting the claim.  A jury subsequently found that defendant Meritor literally infringed the claim and that the infringement was willful.

The CAFC, in reversing the district court’s construction, concluded that the  structures recited in the preamble limited the scope of the claim.  The CAFC reasoned that the steps required manipulation of the specific driveline structures detailed in the preamble such that the steps could not be performed without the referenced driveline system.  Namely, the first step required manipulation of the master clutch and the second step required manipulation of the first and second members of the first clutch.  Additionally, the CAFC construed the first step as necessarily being performed during the particular sequence outlined in the preamble.  That is, the first step was performed during the gear ratio shift described in the preamble.  Accordingly, in the view of the CAFC, the body of the claim only made sense with reference to the preamble; therefore, the preamble gave “life, meaning and vitality” to the claim and was a limitation on claim scope. Thus, the CAFC reversed the district court’s claim construction, and it further reversed the jury verdict of literal infringement, noting that it was undisputed that the accused device did not employ the driveline system recited in the preamble.

In reaching this conclusion, the CAFC was careful to note the differences between Eaton’s patent claim and the claim asserted by Vaupel in Vaupel Textilmaschinen KG v. Meccanica Euro Italia, S.P.A., 944 F.2d 870 (Fed. Cir. 1991).  Vaupel concerned a method claim directed to forming a plurality of patterned strips of fabric woven from threads of synthetic material.  The preamble of the claim at issue in Vaupel recited a “broad weaving machine” having a “sley” and a “breast beam.”  The body of the claim recited a step of “guiding the woven fabric leaving the position where the sley beats up the fabric to allow movement towards the breast beam of said machine, but not in the opposite direction.”  Thus, like the claim in Eaton, the step referenced structures that were only described within the preamble.  Nonetheless, the district court concluded that the language in the preamble did not constitute a structural limitation and also concluded that the claim was infringed. 

The CAFC affirmed both the district court’s claim construction and its infringement determination in favor of Vaupel.  The CAFC reasoned that the term “breast beam” did not mean a specific loom part but was rather a general reference to an area at the front of a loom.  Additionally, the CAFC concluded that the terms sley and breast beam were only used to fix the direction of movement of the woven fabric on the loom.  Thus, unlike the claim in Eaton, the claim in Vaupel did not recite a step that required manipulation of structures described in the preamble.  Rather, the preamble in Vaupel was merely a frame of reference, both for the location of the invention upon a loom and the movement of fabric relative to the loom.  Thus, the preamble did not give “life, meaning and vitality” to the remainder of the claim.

Eaton and Vaupel make it apparent that there are no easily applied universal rules in construing preambles.  Instead, a proper construction can only be achieved by a complete understanding of the invention.  The preamble and body of the claims at issue must then be analyzed in light of this understanding. Only by way of such a detailed analysis can one apprehend whether a preamble is necessary for “life, meaning and vitality.” 

For more information, call Michael Colitz, toll free, at 1-888-688-8500.

 

[1]         Pitney Bowes, Inc. v. Hewlett-Packard Co., 182 F.3d 1298, 1306 (Fed. Cir. 1999).

[2]         Bell Communications Research, Inc. v. Vitalink Communications Corp., 55 F.3d 615, 620 (Fed. Cir. 1995).

[3]        Schumer v. Lab. Computer Systems, Inc., 308 F.3d 1304, 1310 (Fed. Cir. 2002).