Patents by Inventor Robert D. Purnell

Robert D. Purnell has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Antistatic shoe sole
    Patent number: 5426870
    Abstract: A shoe sole construction comprises a polyurethane outer sole having an electrical resistance of approximately 40 MOhms in a standard wet/dry test and an electrical resistance of approximately 20 MOhms in a standard wet/wet test in a test conducted according to British Standard 2050, and a rubber sole insert having an electrical resistance of approximately 1 MOhm positioned adjacent the outer sole. With this construction, static electricity in the sole insert is capable of discharging from the sole insert along a path of least resistance through the outer sole.
    Type: Grant
    Filed: January 21, 1994
    Date of Patent: June 27, 1995
    Assignee: Phurness Pty. Ltd.
    Inventors: Andrew T. Purnell, Robert D. Purnell