Trigonometry Plus Non-Conventional Steps Equals Eligible Subject Matter in Blade Assembly Patent


Henryk Oleksy is the owner of U.S. Patent No. 6,449,529, entitled “Process for contour machining of metal blocks” and directed to methods of determining machining instructions for a milling machine to cut a concave hook in the root section of a turbine blade (‘529 Patent).

In most turbines, projections called hooks located on the interior surfaces of the root sections of turbine blades hold the blades to the rotary wheel of the turbine.  To prevent the blades from wobbling, the curvature of the hook in the root section must be machined to specific dimensions.

In 2006 Oleksy sued GE for infringement of the ‘529 patent, and both parties moved for summary judgment as to the validity of the patent.  The issue was whether the claims of the ‘529 Patent constitute patentable subject matter under Section 101 of the patent law.

Last month Judge Virginia Kendall of the U.S. District Court for the Northern District of Illinois granted Oleksy’s motion and denied GE’s, holding the ‘529 patent valid under Section 101 (Oleksy Opinion).

Claim 1 of the ‘529 Patent includes a recitation that the instructions for a computer numerical control milling machine are “obtained by trigonometric analysis” of the required curvatures of the spinning form cutter and rotary table of the machine.  Standing alone, trigonometric analysis is an unpatentable mathematical formula.

Therefore, the question was whether the claim includes an additional element or elements that constitute an “inventive step.”  The court found that claim 1 of the ‘529 Patent does contain such additional elements including a step of moving the spinning form cutter “in a convex path” while the rotary table rotates “simultaneously from a plus rotation angle to a minus rotation angle and, alternatively, from a minus rotation angle to a plus rotation angle.”

According to the court this step is unconventional and was not used before Oleksy’s invention.  Therefore, the patented process is more than a mere mathematical formula:

As a result, Oleksy did not patent a mathematical formula, he patented a unique process of milling a root section of a turbine blade that happened to include the use of a mathematical formula as part of the process . . . Oleksy’s patent does not pre-empt the use of his trigonometric analysis, he simply forecloses it[s] use with respect to causing a spinning form cutter to move in a convex path to machine the root section of a turbine blade.

The court found an inventive step and also, significantly, noted that the claimed invention is limited to this particular application.  Accordingly, the claimed invention is patent eligible subject matter under Section 101:

Oleksy’s patent contains specifically defined, non-conventional steps.  Moreover, the patent is limited to the particular application of milling the curvature of a hook . . . Oleksy’s process is patent eligible under Section 101.

The court’s decision also addressed claim construction issues and the parties’ motions to dismiss and strike certain claims and defenses.

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Eric Lane

Eric Lane, the founder and principal of Green Patent Law, is an intellectual property lawyer and registered U.S. patent attorney in New York and is a member of the bar in New York and California. Eric has more than two decades of experience working with wind, solar PV, CSP, biofuels, and geothermal, energy storage technologies, carbon capture and sequestration, medical devices, data communications, mechanical, chemical, internet and software.