Patents by Inventor Tzen Chang Tsai

Tzen Chang Tsai 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).

  • Ratchet wrench
    Patent number: 6155140
    Abstract: A ratchet wrench includes a head formed on a handle and having a notch, a gear rotatably engaged in the head and having an opening for receiving fasteners, and a pair of pawls pivotally secured in the head and biased to engage with the gear and to control an active driving direction of the gear. One of the pawls may engage with the gear when the other pawl is engaged in the opening of the gear, and the other pawl is arranged to be engaged with the gear when the previous pawl is engaged in the opening of the gear, such that the gear may be continuously driven by the handle via the pawls.
    Type: Grant
    Filed: September 9, 1999
    Date of Patent: December 5, 2000
    Inventor: Tzen Chang Tsai