Patents by Inventor James Luther Shackelford, IV

James Luther Shackelford, IV 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).

  • CONTROLLING TORSIONAL SHAFT OSCILLATION
    Publication number: 20110197680
    Abstract: Torsional oscillation of a shaft in a swing drive system of an excavator is minimized by monitoring torsional strain of the shaft. An electric motor provides torque to the shaft in response to a drive signal provided by a converter. A compensation circuit produces a compensation signal as a function of torsional strain of the shaft. A field excitation circuit or regulator powers a converter as a function of the compensation signal such that a counter torque is provided to the shaft and torsional oscillation of the shaft is reduced.
    Type: Application
    Filed: April 21, 2011
    Publication date: August 18, 2011
    Applicant: Peabody Energy Corporation
    Inventor: James Luther Shackelford, IV
  • Controlling torsional shaft oscillation
    Patent number: 7948197
    Abstract: Torsional oscillation of a shaft in a swing drive system of an excavator is minimized by monitoring torsional strain of the shaft. An electric motor provides torque to the shaft in response to a drive signal provided by a converter. A compensation circuit produces a compensation signal as a function of torsional strain of the shaft. A field excitation circuit or regulator powers a converter as a function of the compensation signal such that a counter torque is provided to the shaft and torsional oscillation of the shaft is reduced.
    Type: Grant
    Filed: January 18, 2008
    Date of Patent: May 24, 2011
    Assignee: Peabody Energy Corporation
    Inventor: James Luther Shackelford, IV