Patents by Inventor Friedrich Grohl

Friedrich Grohl 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: 4236480
    Abstract: An indicator dial having at least one scale thereon and having at least one illuminable indication area for providing a visual signal of a physical function, wherein the dial comprises a thin transparent plate having an opaque dye coat on one face thereof with at least one area free of the opaque dye coat and having a translucent dye coat of contrasting color in the area, and the scale being on the side of the plate facing a viewer, whereby the scale is visible at all times, but the indication areas are visible to the viewer only when illuminated from behind the dial. The dial is made by applying the dye coats and scale markings in sequential operations by use of a screen printing process.
    Type: Grant
    Filed: December 8, 1978
    Date of Patent: December 2, 1980
    Assignee: VDO Adolf Schindling A.G.
    Inventor: Friedrich Grohl