Patents by Inventor Douglas F. Parker

Douglas F. Parker 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).

  • Variable ratio transmission
    Patent number: 5820505
    Abstract: A variable ratio transmission includes a differential gear assembly coupled to three separate shafts. One of the shafts is coupled to a prime mover and operates as an input shaft to the differential gear assembly. Another of the shafts is connected to a load and operates as an output shaft of the differential gear assembly. The third shaft is coupled to a controlled load that is controlled by the user to adjust the transmission ratio between the input shaft and the output shaft in a continuous manner.
    Type: Grant
    Filed: June 18, 1997
    Date of Patent: October 13, 1998
    Inventor: Douglas F. Parker
  • Grounding and ground fault detection circuits
    Patent number: 4580186
    Abstract: In an AC electric power system including a voltage source having a live conductor and a neutral, a grounding and ground fault detection circuit connected between the neutral and ground potential and comprising, in series, a current limiter, a rectifier, and a signal generator for providing a control signal in response to a ground fault current.
    Type: Grant
    Filed: May 20, 1985
    Date of Patent: April 1, 1986
    Inventors: Douglas F. Parker, W. Garth Bradshaw, Mark J. Augustine