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Patentable subject matter: An American Axle update

By Wayne F. Reinke

BridgeTower Media Newswires

In American Axle, the invention was directed to a method for manufacturing a shaft assembly of a driveline system, historically considered to be patentable subject matter. The first claim addressed included a step of turning a mass and stiffness of a liner. The tuning was qualified in that it was said to be a tuned resistive absorber for attenuating shell vibrations, the liner also being a tuned reactive absorber for attenuating bending mode vibrations.

The Federal Circuit, in what was somewhat of a surprise, found the claim included the application of a law of nature (Hooke’s law — the strain of an elastic solid, e.g., a spring, is proportional to the stress responsible for the strain).

The Federal Circuit found that the claim was ineligible under § 101, because it simply required the application of Hooke’s law to tune a propshaft liner to dampen the two types of vibrations (a goal) with nothing more, though such dampening for two types of vibrations at once was not previously being done in the art.

The Federal Circuit characterized the claim as setting out a goal of tuning a liner to achieve attenuation of certain types of vibration. Further, the Federal Circuit reasoned, as only a goal is presented, it purports to cover any possible way of achieving the goal.

American Axle argued the claim was not simply directed to a goal, as tuning a liner is complicated and may involve extensive computer modeling and trial and error. Thus, American Axle argued, the claim recites an improved tuning method. The court found essentially that there was nothing in the claim regarding the “how” of the tuning, though carefully avoiding use of that term.

To refresh, the Alice two-part test includes, in step one of the test, the court determining “whether the claims at issue are directed to a patent-ineligible concept,” i.e., whether the claims are directed to a judicial exception to the expansive language of 35 U.S.C. § 101. (See Alice Corp. v. CLS Bank Int’l, 573 U.S. 208, 217 (2014) (citing Mayo Collaborative Servs. v. Prometheus Labs., Inc., 566 U.S. 66, 77 (2012)).

The judicial exceptions handed down by the U.S. Supreme Court include abstract ideas, laws of nature and natural phenomena (including products of nature). If it is found that the claims are directed to a patent-ineligible concept, we then “examine the elements of the claim to determine whether it contains an ‘inventive concept’ sufficient to ‘transform’ the claimed abstract idea into a patent-eligible application.” (Id. at 221 (quoting Mayo, 566 U.S. at 72-73, 78)).

In so doing, the elements of the claim are to be considered individually and as an ordered combination. (See Alice at 217.)


On Dec. 28, 2020, American Axle & Manufacturing, Inc. (“American Axle”) filed a compelling petition for writ of certiorari (“the petition”) with the U.S. Supreme Court, after exhausting all avenues at the Federal Circuit, culminating in an evenly split (6-6) decision denying rehearing en banc. The questions presented in the petition were:

  • What is the appropriate standard for determining whether a patent claim is directed to a patent-ineligible concept under step 1 of the court’s two-step framework for determining whether an invention is eligible for patenting under 35 U.S.C. § 101?
  • Is patent eligibility (at each step of the court’s two-step framework) a question of law for the court based on the scope of the claims or a question of fact for the jury based on the state of art at the time of the patent?

The petition showed how the Federal Circuit is fractured with regard to § 101 and has overextended the judicial exceptions to § 101 (the exceptions referred to in the petition as “non-textual”). The petition showed how processes like the claimed industrial manufacturing process were long considered patentable subject matter and that the Federal Circuit holding was otherwise in conflict with Supreme Court precedent. The petition showed how there is a universal plea for § 101 guidance, that this case is the ideal vehicle and the Supreme Court is the appropriate venue, not Congress, as the text of § 101 unambiguous and the issues relate solely to the judicially created exceptions to § 101.

While there were a multitude of amicus briefs filed in favor of the court granting certiorari, the court invited the Solicitor General to file a brief on behalf of the federal government. The patent community has since been patiently waiting for that brief. Until now.


On May 24, 2022, the Solicitor General filed the long-awaited amicus brief in favor of granting certiorari for at least the first question presented as framed in the brief, adding that both steps of the Alice inquiry need clarification. With regard to the second question presented, the Solicitor’s brief mentioned that the court could address the same if necessary.

A key theme in the brief is that claim 22 of the American Axle patent is directed to the type of invention, an industrial process, historically found to be patentable subject matter, citing the court’s decision in Diamond v. Diehr.

The Solicitor General’s brief reiterated that at some level, all inventions touch on the judicial exceptions, such that courts must not find ineligibility simply because a patent-ineligible concept is present. The brief also observed that prior decisions of the court regarding patent eligibility have, at their core, indicated the judicial exceptions are about pre-emption. In the Solicitor’s view, although the Federal Circuit found that claim 22 involves a law of nature and a goal of dampening multiple modes of driveshaft vibration, claim 22 actually goes well beyond simply identifying the goal of reducing multiple modes of vibration, reciting a specific sequence of steps.

With regard to Judge Moore’s strong dissent to the majority split decision at the Federal Circuit, the Solicitor General noted that Judge Moore did not dispute the apparent majority premise that conventional claim limitations should be disregarded at step two.

The Solicitor’s brief goes on to argue that Supreme Court precedent requires that the claim elements must be considered individually and as an ordered combination. Further, the brief notes that other controversial Federal Circuit decisions (Yu v. Apple, a camera; and Chamberlain, a garage door opener) are similarly flawed.

On the heels of the Solicitor General’s brief, the respondents filed a supplemental brief on June 7, 2022, attacking the Solicitor General’s brief. However, the supplemental brief seems unlikely to sway the court. It relies heavily on O’Reilly v. Morse, a very old Supreme Court case. The supplemental brief attempts to characterize the Solicitor General’s amicus brief as asking the Court to overrule both Mayo and Alice, which is obviously not the case.

This saga has an unfortunate ending, at least the American Axle case.

On June 30, 2022, the Supreme Court denied certiorari in American Axle. So, the fight to correct the Federal Circuits’ 101 jurisprudence now goes to Congress. I, for one, am not holding my breath that will happen anytime soon.

Wayne F. Reinke is a partner in the Rochester office of Heslin Rothenberg Farley & Mesiti. His practice focuses on issues related to Internet-based inventions, software, business methods, semiconductor technologies, design patents, and nanotechnology. He can be reached at (585) 288- 4832 or [email protected]

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