Patents by Inventor Luther E. Johnson

Luther E. Johnson 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: 4843888
    Abstract: A tensile test grip for holding a specimen has a pullrod that is mounted in an annular bore, and carries a piston head that fits within a piston chamber, and both the pullrod and piston head are sealed on their outer surfaces with respect to the body forming the piston chamber, to form an enclosed chamber in which hydraulic fluid can be provided to permit swiveling alignment of the pullrod and the piston head relative to the housing that is a function of the direction of loading between the pullrod and the housing. The seal on the pullrod and the seal on the piston head with respect to the respective surfaces on which they seal is on a very short part spherical land to permit the pullrod and piston head to shift with respect to the housing and provide self alignment. The pullrod and piston can swivel freely for a limited amount to provide alignment during tensile loads.
    Type: Grant
    Filed: April 4, 1988
    Date of Patent: July 4, 1989
    Assignee: MTS Systems Corporation
    Inventors: Martin M. Gram, Luther E. Johnson, Carl G. Larsen