Patents by Inventor Ulf Lagerqvist

Ulf Lagerqvist 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).

  • Method and apparatus for controlling an arc welding energy source during an arc welding operation
    Patent number: 4721843
    Abstract: A method of controlling a welding operation during arc welding between a fusible electrode and a workpiece, wherein the welding operation alternates between arc periods and short-circuiting periods, includes the steps of sensing a first parameter of the welding operation, for example the arc voltage between the electrode and the workpiece, generating a first signal representative of the first parameter, sensing a second parameter of the welding operation, generating a second signal representative of the second parameter, filtering the second signal to provide a filtered signal, generating a desired value signal based upon the filtered signal and controlling the welding operation based upon the difference between the desired value signal and the first signal.
    Type: Grant
    Filed: February 6, 1987
    Date of Patent: January 26, 1988
    Assignee: Esab AB
    Inventors: Peter Budai, Ulf Lagerqvist