Patents by Inventor Lupke A. Stefan

Lupke A. Stefan 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: 10759108
    Abstract: A pulsating corrugator is provided with at least one secondary mold block that is selectively used for forming a spigot connection as the corrugated or ribbed pipe is formed. Preferably, the primary mold blocks used to form the corrugated pipe are also used to assist in further cooling of the formed spigot connection once released from the secondary mold block. The corrugator also includes a controller used to provide different air pressure as the mold blocks move past extrusion outlets of an associate extruder.
    Type: Grant
    Filed: October 20, 2017
    Date of Patent: September 1, 2020
    Inventors: Lupke A. A. Manfred, Lupke A. Stefan