Patents by Inventor John Thomas Mark

John Thomas Mark 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).

  • Vacuum tube grid structures of phosmic bronze having copper and copper alloy conical supports
    Patent number: 4076992
    Abstract: A vacuum tube includes a cylindrical cathode around which a frusto-conical control grid extends. The control grid, which is made out of Phosnic bronze, has its larger diameter end attached to the smaller end of a first hollow truncated copper cone. A cylindrical Phosnic bronze screen grid extends coaxially around the control grid. One end of the screen grid is attached to the smaller diameter end of a second hollow truncated cone. The second cone extends around the first cone and is made out of a copper clad alloy of cobalt, nickel and iron. An anode encircles the screen grid.
    Type: Grant
    Filed: June 22, 1976
    Date of Patent: February 28, 1978
    Assignee: RCA Corporation
    Inventor: John Thomas Mark