Patents by Inventor Jens Drefahl

Jens Drefahl 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).

  • Roof covering
    Patent number: 4534142
    Abstract: A roof covering for greening an inclined roof comprises a water-impermeable roof skin, a holding structure placed loosely on the roof, holding projections distributed on said holding structure and engaging in a plant-carrying layer, a tension-resistant filter layer beneath the holding projections, and a drainage underneath said filter layer and having distributed spacers in contact with said filter layer.
    Type: Grant
    Filed: June 23, 1981
    Date of Patent: August 13, 1985
    Inventor: Jens Drefahl