Patents by Inventor Frederick L. Griffith

Frederick L. Griffith 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).

  • Conduits having a shock absorbing shell and method for their formation
    Patent number: 5312658
    Abstract: In accordance with the invention, a concrete conduit is completely encased within a shell of a plastic resin such as polyethylene. The plastic shell functions to insulate the concrete conduit from mechanical shocks thereby preventing breakage and cracking of the conduit. The shell also effectively provides an impermeable barrier for water vapor and a smooth, relatively frictionless, surface for receiving electric cables, wires and the like. The conduit is made by preforming the shell, for example by rotational molding, and filling the shell with pourable cement through a filler hole in the shell. The filler hole can then be closed with a plug of the resin used to form the shell.
    Type: Grant
    Filed: March 5, 1993
    Date of Patent: May 17, 1994
    Assignee: Progressive Polymerics Inc.
    Inventor: Frederick L. Griffith
  • Method for making conduits having a shock absorbing shell
    Patent number: 5217667
    Abstract: A concrete conduit is completely encased within a shell of a plastic resin such as polyethylene. The plastic shell functions to insulate the concrete conduit from mechanical shocks thereby preventing breakage and cracking of the conduit. The shell also effectively provides an impermeable barrier for water vapor and a smooth, relatively frictionless, surface for receiving electric cables, wires and the like. The conduit is made by preforming the shell, for example by rotational molding, and filling the shell with pourable cement through a filler hole in the shell. The filler hole can then be closed with a plug of the resin used to form the shell.
    Type: Grant
    Filed: May 7, 1991
    Date of Patent: June 8, 1993
    Assignee: Progressive Polymerics, Inc.
    Inventor: Frederick L. Griffith
  • Pre-start lubrication system for automotive turbocharger
    Patent number: D328303
    Type: Grant
    Filed: December 28, 1990
    Date of Patent: July 28, 1992
    Assignee: Boda Industries, Inc.
    Inventors: Frederick L. Griffith, Mario A. Turchi, Keff I. Dank