Patents by Inventor David E. Hillgenberg

David E. Hillgenberg 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: 4104349
    Abstract: Method of making a molded container for potted plants from a sheet of organic polymer, is molded in one piece from a sheet of organic polymer material. Rigidity is provided by a peripheral solid lip formed with a horizontally extending lower surface and convexly curved upper surface. One or more drainage apertures are formed through the bottom wall of the container by limited vertical shearing eliminating waste and permitting adjacent portions to be strengthened and raised to dispose the aperture above a supporting surface. In molding the container, a strap of serrated steel is used to cut through the sheet material to define the outer edge of the container lip.
    Type: Grant
    Filed: February 4, 1976
    Date of Patent: August 1, 1978
    Inventor: David E. Hillgenberg
  • Patent number: 3977595
    Abstract: A carton comprising a pair of space-defining members with confronting closing edges which lock by means of a tab latch. The latch includes a tab which extends from one of the closing edges to pass through a loop formed on a wall adjacent the opposite closing edge. The tab includes a terminal portion which extends through the loop and which has a rear surface that conforms to the wall region rearwardly adjacent the loop. The tab also includes a protuberance on its front, outer surface which is insertable through the loop by deformation of the loop and which is retained thereby. In particular embodiments, the carton is integrally formed in one piece of expanded plastic material with sections of the closing edges hinge-connected. In a specific configuration, the walls of the space defining members taper inwardly from the closing edges so that the tab forms an acute angle with the closing edge from which it extends.
    Type: Grant
    Filed: April 7, 1975
    Date of Patent: August 31, 1976
    Assignee: Dolco Packaging Corporation
    Inventor: David E. Hillgenberg