CAFC analyzes 101 issues as to Hooke's Law in AMERICAN AXLE & MANUFACTURING V. NEAPCO HOLDINGS

This was a 101 case:


The district court granted Neapco’s motion and held
that the asserted claims are ineligible under § 101. We affirm in part and vacate and remand in part.



Hooke's Law arises:


In light of the district court’s construction of claim 1,
which requires only controlling characteristics and positioning the liner, we cannot conclude that it is merely directed to Hooke’s law. In contrast with claim 22, which as
construed recites nothing more than a desired result and
an instruction to apply Hooke’s law, we cannot say claim 1
as construed is directed to a particular natural law and
nothing more. The mere fact that any embodiment practicing claim 1 necessarily involves usage of one or more natural laws is by itself insufficient to conclude the claim is
directed to such natural laws. The district court’s opinion
suggests that the broader concept of tuning is an abstract
idea, J.A. 16–17, and the same question may be raised
about the broad concept of positioning. On appeal, Neapco
relied on both the natural law and abstract idea categories
of ineligibility in defending the district court’s decision.
See, e.g., Neapco Resp. Br. 21, 24. But the abstract idea
basis was not adequately presented and litigated in the
district court. We think that it is appropriate to vacate the
judgment as to claim 1 and its dependent claims and remand the case for the district court to address this alternative eligibility theory in the first instance