Patents by Inventor Ingvar Niemi

Ingvar Niemi 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: 5296662
    Abstract: An electric switching device according to the invention comprises two fixed contacts and one movable contact, referred to jointly as the main contact system. The main contact system is located in an oil-insulated cavity enclosed in a housing. In its direction of movement, the movable contact has an extension in the form of a shaft. The shaft is formed with a hydraulic piston by which the movable contact is operated. The hydraulic piston is surrounded by a cavity in which a piston cavity is formed on each side of the hydraulic piston. The piston cavities are oil-filled. The movement of the shaft is determined by an electrically controlled directional valve. The directional valve receives signals as to whether the electric switching device is to be opened or closed. At a given signal, the directional valve distributes a high pressure to the piston cavity that is to be enlarged.
    Type: Grant
    Filed: June 9, 1992
    Date of Patent: March 22, 1994
    Assignee: Asea Brown Boveri AB
    Inventors: Goran Engdahl, Gunnar Molund, Ingvar Niemi