Patents by Inventor Douglas L. Hamilton

Douglas L. Hamilton 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: 7002818
    Abstract: A power converter includes an input circuit that receives DC input power and creates high frequency pulses. A transformer transforms the high frequency pulses into at least two sets of transformed pulses having alternating and opposite polarity. An output circuit connected to the transformer includes a plurality of switches for blocking undesired pulses. A controller controls the switches so that they are on except when blocking undesired pulses, so that a continuous current path is provided through the output circuit.
    Type: Grant
    Filed: December 19, 2003
    Date of Patent: February 21, 2006
    Assignee: Silent Power, Inc.
    Inventor: Douglas L. Hamilton
  • Patent number: 6967852
    Abstract: An electrical power converter receives input power of one type or level at input terminals and supplies output power of another type or level at output terminals. The power converter includes a high frequency transformer, an input circuit connected between the input terminals and the primary of the transformer, and an output circuit connected between the secondary of the transformer and the output terminals, a controller for controlling pulse width of current pulses produced by the input circuit, and a current limiting circuit. The current limiting circuit allows very high surge currents immediately upon demand without waiting for a voltage drop feedback circuit, then dynamically reduces the current limit over time based on the averaged current in the input circuit.
    Type: Grant
    Filed: December 19, 2003
    Date of Patent: November 22, 2005
    Assignee: Silent Power, Inc.
    Inventor: Douglas L. Hamilton
  • Patent number: 6332953
    Abstract: A paper product suitable for use in making envelopes and the like and having enhanced printability. The enhancement in printability is attained through the use of shoe nip calendering. The final product has the following material properties: (1) a basis weight in the range 16-32 lb./1,300 ft2; (2) a density equal to or less than 0.75 g/cc; (3) a smoothness as measured by the Hagerty/Sheffield test (TAPPI Test Method T 538 om-88) greater than 200 Sheffield units; and (4) a Parker Print Surf roughness as measured by the Parker test (TAPPI Test Method T 555 om-94) less than 5.0 microns (measured using a pressure of 10 kgf/cm2 with a soft backing).
    Type: Grant
    Filed: January 7, 2000
    Date of Patent: December 25, 2001
    Assignee: International Paper Company
    Inventors: Kapil Mohan Singh, Alexander A. Koukoulas, Dennis W. Anderson, Phillip Norrdahl, Douglas L. Hamilton