Patents by Inventor Christopher Thorburn

Christopher Thorburn 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: 5573251
    Abstract: A dart flight stem comprises a metal root portion attached by screw thread to a dart barrel. A flight-holding portion is mounted on the root portion for rotation about the longitudinal axis of the flight stem. A shaft extends axially from the flight-holding portion into a complementary bore extending axially from the adjoining end of the root portion. The shaft has a circumferential groove and the peripheral metal wall in the root portion is locally crimped to form radially inwardly peripheral projections in the circumferential groove around the shaft, whereby the flight holding portion is held captive on said root portion. The dart flight stem made by a method of selecting root portion with screw threads at the front end for attachment to a dart barrel. A flight holding portion is mounted on the rear end of the root portion. An axial blind bore is provided in the root portion to establish a rotating fit with a shaft on the flight holding portion.
    Type: Grant
    Filed: August 5, 1994
    Date of Patent: November 12, 1996
    Assignee: Target Sports Limited
    Inventors: Eric Beard, Gary Plummer, Christopher Thorburn