Patents by Inventor Cheng Wai Chun

Cheng Wai Chun 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).

  • Ground fault circuit interrupter
    Patent number: 5933063
    Abstract: A ground fault circuit interrupter has a pair of stationary contacts and a pair of movable contacts mounted in a housing. Also included is an electromagnetic coil mounted in the housing for generating an electromagnetic field. The interrupter also has a plunger and an armature, each slidably mounted at least partially within the electromagnetic coil. The armature can be magnetically driven by the coil against the plunger. A latch means is included for releasably holding the pair of movable contacts against the pair of stationary contacts. A fault detector can detect a fault in an electrical distribution system in order to actuate the electromagnetic coil.
    Type: Grant
    Filed: July 21, 1997
    Date of Patent: August 3, 1999
    Assignee: Rototech Electrical Components, Inc.
    Inventors: Wan Yiu Keung, Cheng Wai Chun
  • Ground fault circuit interrupter
    Patent number: D419531
    Type: Grant
    Filed: October 26, 1998
    Date of Patent: January 25, 2000
    Assignee: Rototech Electrical Components
    Inventors: Wan Yiu Keung, Cheng Wai Chun