Patents by Inventor Hans Helfrich

Hans Helfrich 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).

  • Foot control mechanism for a dental apparatus
    Patent number: 5423231
    Abstract: A foot control mechanism for a dental apparatus has a tiltable actuation member mounted on a base part and an arrangement for holding the tiltable actuation member in a neutral position, which requires sufficient force to move the actuation member in either direction from the neutral position to a switch position. To accomplish this, the structure includes a mounting arrangement utilizing a pair of spaced-apart bearings extending parallel to each other which bearings receive projections on the other element and, preferably, a catch member is provided which provides a resistant force from movement from the neutral position.
    Type: Grant
    Filed: April 28, 1993
    Date of Patent: June 13, 1995
    Assignee: Siemens Aktiengesellschaft
    Inventors: Hans Helfrich, Hermann Landgraf, Josef Hain
  • Foot switch
    Patent number: D342720
    Type: Grant
    Filed: November 18, 1992
    Date of Patent: December 28, 1993
    Assignee: Siemens Aktiengesellschaft
    Inventors: Tilman Phleps, Hermann Landgraf, Hans Helfrich