Patents by Inventor John M. Dowden

John M. Dowden 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).

  • Patent number: 5216220
    Abstract: A method and apparatus for welding together two metal workpieces, at least one of which has thereon a coating material which enters a fluid or visco-elastic phase at a temperature below the melting temperature of the workpieces, the method comprising the steps of subjecting the workpieces to a preliminary preparative treatment at a zone to be welded and thereafter applying (preferably be means of a high-energy beam such as a laser beam) sufficient heat to the workpieces at the weld zone to effect there the welding together thereof, wherein the preliminary preparative treatment comprises preheating the workpieces to the said lower temperature and pressing them together, at the zone to be welded with a force sufficiently great to expel coating material from between the workpieces at the weld zone. thereby to improve the quality of the subsequent weld.
    Type: Grant
    Filed: April 12, 1991
    Date of Patent: June 1, 1993
    Assignee: British Technology Group Ltd.
    Inventors: Michael P. Davis, John M. Dowden, Phiroze D. Kapadia, Kenneth R. Rickwood