Patents by Inventor Hans-Joachim Lippmann

Hans-Joachim Lippmann 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: 4438307
    Abstract: The invention relates to a vacuum switch with cup-shaped switch contact components having an obliquely slit contact carrier and mounted unslit contact ring. The contact carrier consists of copper with or without additional chromium and the contact ring consists of a chromium-copper matrix with or without additions. The electrical conductivity changes rapidly from the contact carrier to the contact ring by a factor of at least 3. The invention is useful for high power vacuum switches.
    Type: Grant
    Filed: March 31, 1983
    Date of Patent: March 20, 1984
    Assignee: Siemens Aktiengesellschaft
    Inventors: Hans-Joachim Lippmann, Gerhard Peche, Hans Bettge
  • Patent number: 3957453
    Abstract: An electric contact material comprises a matrix formed by refractory metal powder particles having interbonding portions and defining pores infiltrated by a solidified molten metal impregnant. The interbonding portions are formed by a solidified molten alloy formed by the refractory metal and an alloying metal, and has a melting temperature above the impregnant's melting temperature. The alloying metal is present in an amount that is small relative to that of the refractory metal but which is effective for the formation of the interbonding portions by the alloy. The material may be made by cold molding the refractory metal powder particles and powder particles of the alloying metal, to form a compact which is then sintered without being under pressure. The interbonding alloy forms during the sintering, and when solidified, forms the interbonding portions between the particles defining the pores. By infiltration these portions are filled with the molten impregnating metal.
    Type: Grant
    Filed: July 23, 1973
    Date of Patent: May 18, 1976
    Assignee: Siemens Aktiengesellschaft
    Inventors: Heinrich Hassler, Hans-Joachim Lippmann