Patents by Inventor David D. Parrish

David D. Parrish 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).

  • Patent number: 4378844
    Abstract: Disclosed are method and apparatus for cutting tubular members from the inside by use of an explosive-induced shock wave. In a particular disclosed embodiment, an electric detonator is used to initiate two equal lengths of linear explosives, each of which initiates a non-electric detonator, to provide dual simultaneous detonation of both ends of an elongate high explosive charge distribution. The resulting collision of detonation shock fronts at or near the center of the explosive charge diverts the shock energy 90.degree. into a 360.degree. distribution about the axis of the charge distribution in a plane perpendicular to that axis to provide the energy to cut a tubular member circumscribing the explosive charge.
    Type: Grant
    Filed: June 29, 1979
    Date of Patent: April 5, 1983
    Assignee: NL Industries, Inc.
    Inventors: David D. Parrish, John A. Barton
  • Patent number: 4291623
    Abstract: Disclosed is a binary electroexplosive device including an explosive lead and a pyrotechnic explosive which may be selectively positioned to initiate the explosive lead upon combustion of the pyrotechnic material. The pyrotechnic material is contained in an initiator assembly which may be inserted within a combination socket and housing which also holds the explosive lead facing the pyrotechnic material but spaced therefrom. Insertion of the initiator assembly within the socket completes electrical connections between a power source and a bridgewire within the initiator assembly embedded in the pyrotechnic material. In a particular embodiment shown, the electroexplosive device is utilized as a blasting cap for a well jet perforating gun wherein the gun may be completely assembled with the exception of the insertion of the initiator assembly in the socket.
    Type: Grant
    Filed: December 29, 1978
    Date of Patent: September 29, 1981
    Assignee: NL Industries, Inc.
    Inventors: Ralph L. Robinson, David D. Parrish