Patents by Inventor Helmut Doll

Helmut Doll 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).

  • Writing utensil with an exchangeable eraser
    Patent number: 4865479
    Abstract: A writing utensil such as a fountain pen is provided with an erasing assembly having a sealing cap which closely covers the wick and is fitted onto the erasing tip in a form molding and friction holding manner; the open end of the cap is provided with an external thread, a similar external thread is formed at the erasing cartridge end of the erasing tip, the pen barrel and the end cap have corresponding internal threads and are threaded onto either the sealing cap or erasing cartridge.
    Type: Grant
    Filed: November 30, 1987
    Date of Patent: September 12, 1989
    Assignee: Herlitz AG
    Inventor: Helmut Doll