Patents by Inventor Friedrich Wilhelm Stumpf

Friedrich Wilhelm Stumpf 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).

  • Control device for a sewing machine
    Patent number: 4067276
    Abstract: The control device controls the sewing speed of a sewing needle automatically in a manner such that the temperature of the sewing needle, subjected to the influence of heat generated by friction with the material being sewn, does not exceed an adjustable predetermined value. Respective measuring members determine the temperature of the sewing needle and the temperature of a reference needle mounted at a location spaced from the sewing needle, and are connected to the input of a differential comparator circuit providing the differential voltage of the measuring members. A signal generator is operatively associated with the sewing needle and produces output pulses responsive to reciprocation of the sewing needle, to control connection of the output of the differential comparator circuit to the input of the sewing machine motor control. The reference needle is substantially identical with the sewing needle.
    Type: Grant
    Filed: October 15, 1976
    Date of Patent: January 10, 1978
    Assignees: Pfaff Industriemaschinen GmbH, Oskar Mohilo, Karl H. Kessler
    Inventors: Oskar Mohilo, Karl H. Kessler, Friedrich Wilhelm Stumpf