Patent Goulash For Engineers


I wrote an article in October 2019 for mechanical engineers (and others) warning that the Section 101 morass, i.e., Patent Goulash, was not limited to computer software business methods or medical diagnostic procedures.  The long twisted arm of unpatentable “natural law” and “abstract ideas” was extending to patent applications for improved mechanical structures.  See Mechanical Engineering and Patentability Goulash. Both this article and the reference pertain to the litigation between American Axle & Manufacturing, Inc. v Neapco Holdings LLC.  The litigated technology pertains to propeller drive shafts.

Warning:  The problem for engineers continues.


The issue in dispute is a patent for an axle liner design and structure that exhibited improved vibration dampening.  The patent was issued but challenged by an alleged infringer.  The trial court invalidated the patent.  

However, the grounds for invalidity were not that the patented idea was not new (Section 102) or would have been obvious to a skilled engineer (Section 103), but rather design was nothing more than application of Hooke’s law.  As may be known, Hooke’s law pertains to the relationship between a structure’s mass, the stiffness of the structural material and the frequency at which the structure will vibrate.  

The case was appealed to the Court of Appeals for the Federal Circuit (“Federal Circuit”).  The decision of invalidity was upheld.  This was discussed in my October article referenced above.  

The decision was appealed for hearing by the entirety of the Federal Circuit panel of justices, i.e., en banc

The Federal Circuit reviewed the petition and declined to take up the appeal on a 6-6 vote.  However, the Federal Circuit did find that the trial court was incorrect in invalidating one of the claims as merely an application of natural law, i.e., Hooke’s law.

This is where the patent goulash topic gets interesting.  

The majority of the Federal Circuit again found several claims as merely claiming natural law to achieve a goal or result.  This is fatal.  See my article “Groundbreaking but not Patentable”.  In that article I direct attention to a dissenting opinion of Justice Reyna wherein he states “Supreme Court precedent has clearly established that a desired goal without means of achieving that goal is an abstract idea”.  See also my analogy to claiming human flight without including structural limitations or elements that will allow such flight.  In that case, claim statement for achieving a goal without stating necessary limitations or elements constitutes an abstract idea.  The majority in American Axle adopts (in my view) this same position. 

This “mere statement of goal” without providing structural limitations to achieve the goal is evident in the patent claim 22, stating:

22. A method for manufacturing a shaft assembly of a driveline system, the driveline system further including a first driveline component and a second driveline component, the shaft assembly being adapted to transmit torque between the first driveline component and the second driveline component, the method comprising: 

providing a hollow shaft member; 

tuning a mass and a stiffness of at least one liner, and 

inserting the at least one liner into the shaft member; 

wherein the at least one liner is a tuned resistive absorber for attenuating shell mode vibrations and wherein the at least one liner is a tuned reactive absorber for attenuating bending mode vibrations.

It should be recognized that the claim does not state how the liner is “tuned” for attenuating shell mode vibrations or bending mode vibrations.

Such a claim is invalid and merely recites or requires the application of a natural law or abstract idea to achieve a goal.  This is consistent with Justice Reyna’s dissent in Amdocs (Israel) Limited v. Openet Telecom, Inc., 841 F.3d 1288 (2016).  The obvious practice point is don’t write claim like this.

Continuing with American Axle, the Federal Circuit sent claim 1 back to the trial court for further action.  In so doing, the Federal Circuit found that there was an indication of a liner “positioning” limitation within claim 1 that could define a structural limitation the “tuning” of the lining for vibration attenuation.  

Added interest is supplied by the dissent of Justice Moore, both in the original Federal Circuit opinion of American Axle and in the modified ruling discussed above.  Justice Moore validly criticizes the use of Section 101 and natural law/abstract ideas to invalidate claims that really properly should be scrutinized under Section 112 for lack of enabling limitations to achieve the purpose of the claim.  This she has termed “Patent Goulash”.  Further she notes the majority continues to muddle the inquiry of whether a claim includes a natural law.  “It can not suffice to hold a claim (invalid as) directed to a natural law simply because compliance with natural law is required to practice the method.”


Routine engineering claims may become embroiled in the abstract idea/natural law morass of Section 101.  This has been termed Patent Goulash.  Recall this topic rose to the surface in regard to attempts to patent known or routine business method through utilization of computer software.  The courts have never been able to consistently apply its formulated test to address this issue.  Now the muddle may now be extending into new areas of technology.

© David McEwing 2020