Patents by Inventor John R. Duncan

John R. Duncan 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).

  • Pulsed direct current arc welding
    Patent number: 4421972
    Abstract: A method of arc welding is disclosed. Specifically, a method of pulsed direct current (DC) arc welding is disclosed wherein special pulses of positive direct current are used to weld together work pieces. The special DC pulses are capable of dissipating difficult to reduce oxides which may be present on the surfaces of the work pieces without using a flux. The method is especially useful for fluxless arc welding of aluminum, particularly thin wall aluminum tubing used in making heat exchangers for air conditioning systems.
    Type: Grant
    Filed: April 9, 1981
    Date of Patent: December 20, 1983
    Assignee: Carrier Corporation
    Inventors: John R. Duncan, Roderick G. Rohrberg, Ross A. Moyer, William E. Wright, Sr.