Patents by Inventor Gunther Harmsma

Gunther Harmsma 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).

  • Mine roof supports
    Patent number: 4191497
    Abstract: A roof support unit for a walking frame roof support assembly is provided with a two part goaf shield. One the goaf shield parts is connected, by means of a link, to the roof cap of the unit; the other goaf shield part being connected, by means of a link, to the floor sill of the unit; and the two parts being hinged to one another. At least one of the links is such as to permit the roof cap to be retracted by an amount sufficient to permit the advance of the unit while preventing the hinged connection between the two goaf shield parts moving towards the goaf side of the mine working.
    Type: Grant
    Filed: July 3, 1978
    Date of Patent: March 4, 1980
    Assignee: Gewerkschaft Eisenhutte Westfalia
    Inventors: Helmut Poklekowski, Klaus Seeberger, Gunther Harmsma