Patents by Inventor Lennart gren

Lennart gren 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).

  • Method for manufacturing a corrugated pipe, and a corrugated pipe manufactured by the method
    Patent number: 5975143
    Abstract: The invention relates to a method for manufacturing a multi-layer corrugated pipe and to a corrugated pipe manufactured by the method and comprising an inner tube (2), a corrugated outer tube (5) and a plastic layer therebetween. Separate layers (3,6) of plastic are formed on the outer surface of the inner tube (2) and the inner surface of the outer tube (5), said separate layers of plastic being affixed to one another at least at the web portions (5a) of the corrugations of the outer tube (5) when the inner tube and outer tube are connected.
    Type: Grant
    Filed: December 9, 1997
    Date of Patent: November 2, 1999
    Assignee: Uponor B.V.
    Inventors: Jyri Jarvenkyla, Bjorn Olsson, Dieter Scharwachter, Lennart gren