Patents by Inventor Paul E. Lowrigkeit

Paul E. Lowrigkeit 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: 4052131
    Abstract: A paving stone module in the form of a slab of substantially even thickness of a trapezoidal shape having substantially flat upper and lower surfaces, four side and end walls and a plurality of elongate apertures extending from the upper to the lower surface, the side and end walls being withdrawn inwardly toward the lower surface of the stone, the apertures being narrower at their upper ends adjacent the upper surface of the stone, and upper marginal portions of the side, end and aperture walls define projecting edges. Along two or more outer walls of the stone may be provided spacer shoulders having an abutment surface extending perpendicularly of the lower and upper surfaces of the stone.
    Type: Grant
    Filed: April 23, 1976
    Date of Patent: October 4, 1977
    Inventor: Paul E. Lowrigkeit