Avoiding the “Abstract Idea” Trap Against Patentability


I have written many times of the ambiguity created by the courts in the Alice and Mayo decisions regarding what is patentable subject matter.  I am today suggesting a method of “avoiding the abstract idea trap against patentability”. What I am referring to is the rejection of patentable innovations on the basis that the patent is merely claiming an abstract idea.  An abstract idea can be a mathematical formula, a method of organizing human behavior, or mental processes.  This is part of the Section 101 exception to patentable subject matter.  In addition to abstract ideas being non-patentable, natural phenomena or natural laws are not patentable.

The USPTO or courts look to the patent claim to determine whether the subject matter is patentable.  This examination can exclude valuable information or perspective contained in the specification of the patent (or patent application).  Since the text of the claim may be the exclusive subject of examination regarding patentable subject matter, I am proposing using expanding the “preamble” portion of the claim to ensure that the claim clearly describes the claim scope.  By clearly describing the claim scope, the examiner or court will be less likely to overly focus on a mathematical relationship or organization method that is only a part of the claimed innovation.  For reasons clarified below, I want the preamble to “breath life and understanding” into the claim.


First, patent claims are typically confusing to the lay person.  They are, however, the most important part of a patent.  Each claim creates a set of boundary lines (claim limitations) that define the scope of the invention.  (Since most patent contain multiple claims, it is therefore obvious the inventor can have several alternate methods of defining the single invention of the patent.)

Each patent comprises three parts.  There is the written description of the invention (specification) supplemented and integrated by drawings if necessary, a summary (abstract) and one or more claims.  The specification fully describes the invention, providing background of the prior art, with non-limiting disclosures of different embodiments or examples of the innovation.

Each claim also comprises three parts.  First is the preamble (introduction).  Second is a transition phrase or word such as “comprising”, “consisting of” or “consisting essentially of”.  Third are the claim limitations.  Typically, the claim limitations or claim elements are the most important part of each claim.  It may be worthwhile to note that a claim is grammatically structured as a single sentence.

A simple example of a claim could be:

A device comprising (a) a motor (b) a multi-gear transmission connected to the motor, and (c) a wheel connected to the transmission wherein the rotation of the wheel has a relationship to motor speed of RPM(wheel) = RPM(motor) x T(gear ratio).

In this example, the preamble is simply the word “device”.  The transition phrase is “comprising”.  Items (a) through (c) are the claim limitations.

Typically, only the claim elements would be examined to determine if claim constituted patentable subject matter.  Here the claim elements include a mathematical formula.  Recall a mathematical formula may be an abstract idea and therefore not patentable subject matter.  The USPTO October 2019 guidelines repeat that “when a claim recites a judicial exception . . . the claim requires further analysis in order to determine its eligibility.”


I am suggesting expanding the preamble (which is part of a claim) to explain the invention as more than a relationship of component speeds determined by a mathematical expression of transmission gear ratio.

For example, the expanded preamble could state (assumed consistent with the details stated in the specification and drawings) “a variable speed cargo carrying motor powered vehicle” comprising: . . .  .  An alternate example of an expanded preamble could be “a motor powered vehicle capable of carrying cargo at variable speeds” comprising . . .  . 

This may look like simply stating the intended use of the device of the first claim statement.  Statements of intended use are not viewed as structural limitations within the claim elements and therefore may not be relevant to determining whether the claim is essentially an abstract idea of wheel rotation speed being a mathematical function of motor speed and transmission gear ratio.  

I am arguing that the expanded preamble is adding structural elements, i.e., a vehicle and cargo carrying capacity.  

I am also aware that typically a claim preamble is not viewed as containing claim limitations.  An exception is that when the preamble must be reviewed to “breath life and meaning into the claim”.  Reference is made to the often cited decision of In re Wertheim, 541 F.2d 257 (CCPA 1976).

A preamble may be limiting if: “it recites essential structure or steps”; claims “depend on a particular disputed preamble phrase for antecedent basis”; the preamble “is essential to understand limitations or terms in the claim body”; the preamble “recit[es] additional structure or steps underscored as important by the specification”; or there was “clear reliance on the preamble during prosecution to distinguish the claimed invention from the prior art.”  See Catalina Mktg. Int’l, Inc. v. Coolsavings.com, Inc., 289 F.3d 801 (Fed. Cir. 2002).  

It is acknowledged that what constitutes a situation requiring reference to the preamble to “breath life or meaning” into the claim is not clear.  However, it may be the key to opening examination of the entire patent and prosecution history to determine whether the claim is merely reciting an abstract idea.  This provides a much broader platform to argue the true scope of the invention, in contrast to the merely the statement of claim elements.  Again, see the limited text of the claim elements in the hypothetical above, i.e., 

“(a) a motor (b) a multi-gear transmission connected to the motor, and (c) a wheel connected to the transmission wherein the rotation of the wheel has a relationship to the motor speed of RPM(wheel) = RPM(motor) x T(gear ratio).”

The above stated claim limitations provide no basis to argue the mathematical formula is only an element defining a motor vehicle for carrying cargo.  To the contrary, the mathematical formula appears to dominate the claim limitations, thereby possibly tilting the abstract idea analysis away from patentability. 

It is acknowledged that my argument is contrary to the common wisdom that fewer words are better in a claim to avoid creation of an unintended limitation.  But my point is that if you are drafting claims for a development that may be comprised of a mathematical formula or method of organizing human behavior or a mental process, an expanded preamble may be desirable.  Again, the USPTO guidance on evaluating suspect claims states that the claim is to be evaluated.  The claim preamble is part of the claim.  Also statements contained within the claim elements of intended use may not be limiting or distinguishing.

I would argue the above claim limitations do not “describe a structurally complete invention”, i.e., the claim limitations omit the necessary structure of a vehicle and further the structure of the vehicle having cargo carrying capacity.  See Arctic Cat Inc v. GEP Power Products, Inc., 919 F.3d 1320 (CAFC 2019).  Note in Pacing Techs. v. Garmin Int’l, 778 F.3d 1021 (CAFC 2015) a claim preamble “A repetitive of motion pacing system for pacing a user” was deemed to be a claim limitation.  Note this text did not appear in the body of claim elements but was considered part of the claim.  The court stated that not including the “repetitive motion pacing” limitation would cause the remaining claim elements to lack an antecedent basis, i.e., it was a necessary component to describe the invention.


Patent applications for computerized business methods (is it really just a mental process using a computer?) or applications incorporating a mathematical relationship within the claim elements can be anticipated to be subject of an examiner’s challenge that the subject is not patentable subject matter.  As I have previously written, the decisions provide little guidance.  

If I suspect that my claim(s) are going to be challenged, I want to have the claim text provide a “foot hold” to argue that the claim is much more than a computerized mental process or mathematical relationship.  Therefore I have begun expanding the preamble to create a focal point to assist in determining the full and proper scope of the invention.  It is not a panacea.  Also great care must be taken to minimize unintended claim limitations from creeping into the claim scope.  This obviously requires understanding the inventor’s goals as well as the inventor’s perceived scope of his/her invention.