Patents by Inventor Carl Elfgren

Carl Elfgren 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).

  • Oil-filled apparatus with means for achieving pressure between parts thereof
    Patent number: 3936784
    Abstract: In an oil-filled apparatus, such as a transformer, having parts between which pressure is to be applied, such pressure is produced by providing between the parts bodies of an elastomer which absorbs the oil and expands as a result of such absorption. Such bodies may be used between windings and cores or as a seal between a transformer lid and a flange.
    Type: Grant
    Filed: May 23, 1974
    Date of Patent: February 3, 1976
    Assignee: Allmanna Svenska Elektriska Aktiebolaget
    Inventors: Carl Elfgren, Erich Spicar