Patents by Inventor Charles R. Hallengren

Charles R. Hallengren 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).

  • Apparatus for producing threaded self-tapping stainless steel screws
    Patent number: 4289006
    Abstract: A process for producing self-tapping screws from an austenitic 300 series stainless steel material wherein a blank of such material is chilled prior to a thread rolling operation so that the threads are formed while the blank is in a chilled condition. A preferred apparatus for practicing such a method utilizes an insulated tunnel surrounding the feed track which leads to the thread roller. Fluid refrigerant is fed to the interior of the tunnel to chill the blanks immediately prior to the thread rolling operation.
    Type: Grant
    Filed: January 8, 1979
    Date of Patent: September 15, 1981
    Assignee: Illinois Tool Works Inc.
    Inventor: Charles R. Hallengren