Chapter §2.02 Components of Patent Claims

• Jurisdiction: United States

§2.02 Components of Patent Claims

Every patent claim has three parts: a preamble, a transition, and a body.⁹⁴ As the role of each of these parts is described below, consider the following claim as an example:

1. A widget comprising:

Part A;

Part B; and

Part C, attaching said Part A to said Part B;

wherein said Part A is made of copper and said Part B is made of lead and said Part C is made of gold.

[A] Preamble

[1] Introduction

A preamble is a short and plain expression of what the invention is. In claim 1 above, the words "[a] widget" are the preamble. The preamble need not include an express reference to one of the four statutory classifications of potentially patentable subject matter under 35 U.S.C. §101 (i.e., process, machine, manufacture, or composition of matter),⁹⁵ so long as it is clear from the entirety of the claim that the invention fits within one or more of those classifications.⁹⁶ In the above example, it is clear that the claimed widget is either a manufacture or a machine.

[2] Preamble Language as Claim Limiting

Claim preambles are typically longer than just one or two words. Often the preamble will include language stating a purpose or use for the invention. In such cases the qualifying language in the preamble is sometimes, but not always, treated as a limitation of the claim.

For example, consider the following reformulation of the example claim set out above:

1. A widget for use in marine applications comprising:

Part A;

Part B; and

Part C, attaching said Part A to said Part B;

wherein said Part A is made of copper and said Part B is made of lead and said Part C is made of gold.

The preamble of this claim is the entire phrase, "[a] widget for use in marine applications." At issue is whether the qualifier "for use in marine applications" represents a limitation of the claim, such that an identical widget, if used on land rather than in the water, would not literally infringe the claim. In other words, if preamble language is considered limiting, then that language must be met by an accused device to establish literal infringement.

The general rule (subject to many exceptions) is that preamble language is not limiting.⁹⁷ Where the body of the claim (i.e., the language following the transition) recites a structurally complete invention and the preamble language states only an intended purpose or use for that invention, the preamble language is generally not limiting.⁹⁸ Language that appears only in the preamble of a claim, not repeated or referred to in the body of the claim, is less likely to be held a limitation of the claim.⁹⁹ A similar result obtains when preamble language is considered merely laudatory.

For example, the patent in suit in Allen Eng'g Corp. v. Bartell Indus. concerned certain concrete riding trowels used to smooth the surface of freshly poured concrete.¹⁰⁰ The preamble and transition of a representative claim recited a "self-propelled, fast steering motorized riding trowel for finishing a concrete surface, said riding trowel comprising. . . ."¹⁰¹ To avoid a potential §102(b) on sale bar, the patentee argued that the preamble phrase "fast steering" should be construed as a limitation of the claims. The Federal Circuit disagreed, siding with accused infringer Bartell that "fast steering" was simply a laudatory term setting forth the invention's purpose. "Fast steering" was "a relative term, and no interpretive frame of reference [wa]s provided in any of the claims or in the specification."¹⁰² Nothing in the record indicated that a person of ordinary skill would understand the meaning of "fast steering" without such a frame of reference. Moreover, the preamble phrase "fast steering" failed to give "life, meaning and vitality" to the claimed structure. Thus, the Federal Circuit concluded, the phrase was not entitled to any claim-limiting meaning.

A similar result flows from the "widget" example claim set forth above. The "marine applications" language of the preamble is not referred to in the body of the claim, and the body recites a structurally complete invention. The "marine applications" language of the preamble merely states an intended use for the widget. Thus, it would not likely be construed as limiting. Unauthorized use of the claimed widget on land would still literally infringe the claim (assuming that all limitations recited in the body of the claim, discussed below, are met).

In contrast with the two previous examples, the Federal Circuit holds that preamble language is considered limiting if the language is necessary to give "life, meaning and vitality" to the claim or if the preamble language recites essential structure or steps.¹⁰³ In particular, if the preamble terminology is repeated and referenced in the body of the claim, it is most likely limiting. When limitations in the body of a claim "rely upon and derive antecedent basis from the preamble, then the preamble may act as a necessary component of the claimed invention."¹⁰⁴

The preamble language at issue in Bicon, Inc. v. Straumann Co. is illustrative.¹⁰⁵ The patent in suit was directed to an apparatus for use with dental implants. The invention involved a plastic cuff designed to preserve a space around a dental implant. More specifically, a dental implant prosthesis of the type contemplated by the patent included (1) a root member implanted in a patient's jaw bone, which root member was attached to (2) an abutment that protruded above the patient's gum line to provide the structure for attaching a crown (the tooth-shaped cap placed over the abutment). Temporary installation of the invented plastic cuff kept the patient's gum tissues from closing around the abutment while the patient's jaw and mouth continued to heal. After healing had completed and the plastic cuff removed, a dentist could take advantage of the space left by the cuff to affix the permanent crown to the abutment at a point beneath the patient's gum line. Affixing the crown beneath the gum line advantageously maintained the natural look of the patient's gum line with the crown installed.

The pertinent claim of the patent recited, with the preamble language emphasized:

5. An emergence cuff member for use in preserving the interdental papilla during the procedure of placing an abutment on a root member implanted in the alveolar bone of a patient in which the abutment has a frusto-spherical basal surface portion and a conical surface portion having a selected height extending therefrom comprising

a generally annular member formed of biocompatible synthetic plastic having first and second ends, a bore extending from the first to the second ends, the bore having a taper generally matching that of the conical surface portion of the abutment, the larger end of the bore being at the first end, the outer surface of the annular member forming a feathered edge with the bore at the first end of the annular member, the distance between the first and second ends being less than the height of the conical surface, the diameter of the cuff member increasing in the direction going from the first end to the second end, and a radially inwardly extending flexible lip formed at the first end of the cuff member. ¹⁰⁶

To establish infringement by the accused device, the patentee argued that the preamble's reference to the abutment was not a limitation of the claim, but rather merely described the purpose or intended use of the emergence cuff. In other words, according to the patentee, the claimed invention was the emergence cuff only. Use of the cuff on any type of abutment would infringe, whether or not such abutment had the recited geometry of a "frusto-spherical basal surface portion and a conical surface portion."

Agreeing with a district court, the Federal Circuit rejected the patentee's argument that the preamble language pertaining to the abutment was not limiting. The correct construction of claim 5 treated the invention as the emergence cuff used in conjunction with an abutment having the features recited in the claim, namely, the "frusto-spherical basal surface portion and a conical surface portion." The appellate court concluded that the preamble recited "essential elements" of the invention pertaining to the structure of the abutment used with the claimed emergence cuff.¹⁰⁷ The recitation of the abutment's structural features in the preamble indicated that the claims drafter chose to use both the preamble and the body of the claim to define the subject matter of the claimed invention. Certain limitations in the body of the claim would be rendered meaningless if the preamble language were ignored.

Moreover, the body of claim 5 did not recite the complete invention, but instead referred back to features of the abutment recited in the preamble. In other words, references to the abutment in the body of claim 5 derived their antecedent basis from the preamble language. The preamble-recited structure for the abutment went "well beyond what [wa]s necessary to describe the intended purpose of the emergence cuff."¹⁰⁸ The shape and height recitations for the abutment "d[id] not serve to describe the function of the emergence cuff, but instead [we]re necessary to define the structure of the claimed device."¹⁰⁹

[B] Transition

The transition of the example claim to a "widget" set forth above is the single word "comprising." The transition is a key code word or term of art that affects the scope of the claim. Three claim transitions are most commonly used in U.S. patent claiming practice: "comprising," "consisting of," and "consisting essentially of."¹¹⁰ Each is discussed below.

[1] "Comprising"

The "comprising" transition is the most prevalent,¹¹¹ for good reason. When "comprising" is used as a claim transition, it means "including" or "having" or "containing" the elements listed following the transition word, but not limited to the listed elements.¹¹² Use of a "comprising" transition indicates that the patent claim is open in scope.¹¹...