Patents by Inventor Einar Trygstad

Einar Trygstad 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).

  • Battery charge indicator having improved resolution
    Patent number: 5869952
    Abstract: Apparatus indicates a charge on a battery that has a predetermined operating range. The apparatus includes a thermochromatic material for displaying the charge level of the battery, and a resistive heating device, which is in thermal contact with the thermochromatic material, for generating heat for activating the thermochromatic material. A controlling device which is connected to the resistive heating device is also included for controlling the heat generated by the heating device so that the thermochromatic material has sufficient resolution to indicate the charge on the battery over a substantial portion of the thermochromatic material.
    Type: Grant
    Filed: August 7, 1997
    Date of Patent: February 9, 1999
    Assignee: Wahl Clipper Corporation
    Inventors: Curtis William Fisher, Einar Trygstad