Patents by Inventor Erkki I. Leinonen

Erkki I. Leinonen 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).

  • Impulse induced eddy current type detector using plural measuring sequences in detecting metal objects
    Patent number: 4894619
    Abstract: The invention relates to a method and an apparatus for detecting metal objects in a metal detecting apparatus using impulse techniques. The metal detector comprises a compensation circuit arranged in between the transmitter system (13) and the receiver system (14) in order to compensate the mutual inductance between the transmitter (11) and the receiver (12). The compensation circuit is advantageously operated so that the signal caused by the metal object in this detector is measurable during both at least two measuring sequences (21,22) located within the range of the cut-off peak of the transmitter current and during at least one measuring sequence (23) located outside the range of the cut-off peak of the transmitter current.
    Type: Grant
    Filed: July 22, 1987
    Date of Patent: January 16, 1990
    Assignee: Outokumpu Oy
    Inventors: Erkki I. Leinonen, Kari T. J. Aittoniemi