Patents by Inventor Long-Jang Li

Long-Jang Li 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).

  • Method and apparatus for sensing armature position in direct current solenoid actuators
    Patent number: 5942892
    Abstract: An apparatus detects a position of an armature within a solenoid coil by superimposing a fixed frequency sensing signal onto the coil driver signal. The combined signal is applied to the solenoid coil and an alternating current component varies with changes in inductance of the solenoid coil that result from position changes of the armature. A current sensor produces an output signal indicating a level of current flowing through the solenoid coil and a filter extracts the alternating component of that output signal that results from the sensing signal. A position circuit determines the position of the armature from an output from the filter.
    Type: Grant
    Filed: October 6, 1997
    Date of Patent: August 24, 1999
    Assignee: Husco International, Inc.
    Inventor: Long-Jang Li