Claims with Functional Language

• Author: Ronald D. Slusky
• Pages: 163-186

CHAPTER TWELVE

Claims with Functional Language

Certain kinds of claims are said to be “functional.” But what that actually

means depends on whom you ask. Judge Giles Rich once observed that

“[f]ew words in patent law have acquired more diverse meanings than

the word ‘functional.’”1

The practical importance of this topic is that functional language

relied on for patentability may not do so as a matter of law. On the other

hand, examiners sometimes reject claims as being “functional” in situa-

tions where the claim is perfectly fine.2

This chapter has more legal discussion and case citations than other

parts of the book. It is important that readers understand and absorb the

case law principles that have built up over time in order to deal with the

practicalities of drafting, and arguing for the patentability of, claims with

functional language. It is vital to know when a claim is, in the lexicon of

this chapter, “unduly functional” and thus needs to be revised.

“Functional Language” but Not “Functional Claim”

It proves useful to talk about claims that have “functional language” but,

as we will see, it is best to avoid the terms “functional claim” and “func-

tional claiming.”

We begin with what it means for a claim to have “functional lan-

guage” or, equivalently, “functional recitation(s).” We don’t need a

strict definition; in the end, we will be analyzing our claims based on

what they actually say, rather than whether any particular recitation

meets anyone’s idea of what constitutes functional language. Indeed, the

goal of this chapter is to enable the reader to readily assess whether a

given claim with functional language is patentable or not based on first

principles.

1. In re Fuetterer, 319 F.2d 259, 266 n.9, 138 USPQ 217 (Fed. Cir. 1963).

2. See, e.g., K-2 Corporation v. Salomon SA, 191, F.3d 1356, 1366–68, 52 USPQ2d 1001

(Fed. Cir 1999); Wright Medical Technology, Inc. v. Osteonics Corp., 122 F.6d 1440, 1443–44,

43 USPQ2d 1837, 1840 (Fed. Cir. 1997).

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164 CHAPTER TWELVE

A useful working definition of functional claim language is any reci-

tation that is other than a purely physical characterization of a tangible

object. Functional language thus encompasses, inter alia, statements of

function, functionality, or result; actions; relationships in time or space;

properties; capabilities; and modes of use. The italicized language in the

following claims is functional language at issue in reported cases that we

will look at in this chapter:

12.1 The use of . . . electro-magnetism . . . for marking or printing

intelligible characters, signs, or letters, at any distances.3

12.2 A glue comprising cassava carbohydrate rendered semifluid

by digestion and having substantially the properties of animal glue.4

12.3 In an apparatus for determining the location of an obstruc-

tion in a well having therein a string of assembled tubing sections

interconnected with each other by coupling collars, . . .

means . . . for receiving pressure impulses from the well . . . and

means . . . for tuning said receiving means to the frequency of echoes

from the tubing collars . . .5

In an apparatus context, a functional recitation is often said to be one

that defines a structural element by what it does, as opposed to what it is.

A means-plus-function recitation is, by its nature, a functional recitation.

Even a single word reciting a structural element can be functional. “Slab”

is a structural recitation, while “door” is a functional characterization of

a slab having the function of access control. “Filter,” “brake,” “clamp,”

“screwdriver,” and “lock” are all structural elements expressed in func-

tional terms.6 A method step is the quintessential functional recitation,

being typically a statement of action or mode of use. We do not usually

think of method steps as being inherently functional. But it helps to rec-

ognize their inherently functional nature because functional characteriza-

tions of structural elements are often method-like.

Although we will talk about functional claim language, it is best to

avoid the terms “functional claim” and “functional claiming” because

those terms mean different things to different people. To talk about a

claim being functional—at least in the pedagogic setting of this book—is

to surely sow the seeds of confusion.

3. O’Reilly v. Morse, 56 U.S. 62 (1854).

4. Holland Furniture Co. v. Perkins Glue Co., 277 U.S. 245 (1928).

5. Halliburton Oil Well Cementing Company v. Walker et al, 329 U.S. 1, 71 USPQ 175

(1946).

6. See, e.g., In re Swinehart, 439 F.2d 210, 169 USPQ 226 (Fed. Cir. 1971); Greenberg v.

Ethicon Endo-Surgery, Inc., 91 F.3d 1580, 39 USPQ2d 1783 (Fed. Cir. 1996).