Pax Accuses Design Firm of Infringing Mollusk-Inspired Rotor Patent


Pax Scientific, Inc. (“Pax”) is a San Rafael, California company that specializes in fluid-handling technology used in applications such as fans, mixers, pumps, turbines, heat exchangers, ducts and propellers.  Pax owns U.S. Patent No. 5,934,877 (‘877 patent), entitled “Rotor with logarithmic scaled shape”.

The ‘877 patent is directed to a rotor, the surface of which is configured according to a logarithmic curve known as the Fibonacci Progression, or the Golden Section.  According to the ‘877 patent, this type of surface is commonly found in shells of the phylum Mollusca, particularly in the classes Gastropoda (that’s squid, cuttlefish and octopus to you and me) and Cephalopoda (e.g., snails and slugs).


This is an example of biomimetics, the application of systems found in nature to the study of engineering and the development of technology.  The ‘877 patent states that the invention “enables fluids to move over the surfaces of the rotor in their naturally preferred way, thereby reducing inefficiencies created through turbulence and friction…”

Claim 1 of the ‘877 patent reads:

A rotor for use with a fluid flow generator or reactor, said rotor being intended to rotate about a central axis and having a surface which defines an arcuate fluid pathway for fluid flow about the central axis about which the rotor is able to rotate, wherein the surface has the configuration of a logarithmic curve substantially conforming to the Golden Section.

Last month Pax sued Re:Thought, LLC (Re:Thought), a Colorado product design consulting firm, and Robert Irwin, the company’s co-founder, in federal court in San Jose, alleging that the firm’s Biometric Horizontal Wind Axis Turbine (BioHAWT) infringes the ‘877 patent. 

According to the complaint (pax_complaint.pdf), Irwin repeatedly contacted Pax’s president and CEO, Jay Harman, about developing a wind turbine using the techniques of biomimetics.  Pax alleges that Irwin revealed details about his design, including pictures and sketches, and solicited technical advice from Harman. 

Despite being warned that his design would infringe Pax’s ‘877 patent, the complaint states, Irwin and Re:Thought displayed a prototype of the BioHAWT in Denver in the fall of 2008.  The complaint accuses Re:Thought of direct infringement and and Irwin of contributory infringement and inducing infringement.

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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.