Patents by Inventor Donald J. Keefe

Donald J. Keefe 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).

  • DC-AC converter for supplementing an AC power source
    Patent number: 4528457
    Abstract: A DC-AC converter for supplying power from a DC power source to a load that is also supplied power by an AC power source. The DC power source is applied to the load with alternating polarity at the frequency and phase of the AC power source. Transients are reduced by limiting the application of the DC power source to the load to less than the duration of each half cycle of the AC power source.
    Type: Grant
    Filed: February 28, 1983
    Date of Patent: July 9, 1985
    Inventors: Donald J. Keefe, Oscar D. Despe
  • Count-doubling time safety circuit
    Patent number: 4277308
    Abstract: There is provided a nuclear reactor count-factor-increase time monitoring circuit which includes a pulse-type neutron detector, and means for counting the number of detected pulses during specific time periods. Counts are compared and the comparison is utilized to develop a reactor scram signal, if necessary.
    Type: Grant
    Filed: June 23, 1978
    Date of Patent: July 7, 1981
    Assignee: The United States of America as represented by the United States Department of Energy
    Inventors: Gordon K. Rusch, Donald J. Keefe, William P. McDowell
  • Automatic sweep circuit
    Patent number: 4236067
    Abstract: An automatically sweeping circuit for searching for an evoked response in an output signal in time with respect to a trigger input. Digital counters are used to activate a detector at precise intervals, and monitoring is repeated for statistical accuracy. If the response is not found then a different time window is examined until the signal is found.
    Type: Grant
    Filed: November 16, 1978
    Date of Patent: November 25, 1980
    Assignee: The United States of America as represented by the United States Department of Energy
    Inventor: Donald J. Keefe
  • Tape transport mechanism
    Patent number: 4144454
    Abstract: A device is provided for transporting, in a stepwise manner, tape between a feed reel and takeup reel. An indexer moves across the normal path of the tape displacing it while the tape on the takeup reel side of the indexer is braked. After displacement, the takeup reel takes up the displaced tape while the tape on the feed reel side of the indexer is braked, providing stepwise tape transport in precise intervals determined by the amount of displacement caused by the indexer.
    Type: Grant
    Filed: January 27, 1977
    Date of Patent: March 13, 1979
    Assignee: The United States of America as represented by the United States Department of Energy
    Inventors: Edward F. Groh, William McDowell, Norbert S. Modjeski, Donald J. Keefe, Peter Groer
  • Monitoring circuit for reactor safety systems
    Patent number: 3979256
    Abstract: The ratio between the output signals of a pair of reactor safety channels is monitored. When ratio falls outside of a predetermined range, it indicates that one or more of the safety channels has malfunctioned.
    Type: Grant
    Filed: March 4, 1975
    Date of Patent: September 7, 1976
    Assignee: The United States of America as represented by the United States Energy Research and Development Administration
    Inventor: Donald J. Keefe