Patents by Inventor Bob B. Ha

Bob B. Ha 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).

  • Hammer drill
    Patent number: 6684964
    Abstract: A hammer drill with rolling contact at the contact surfaces for transmission of axial force between a drive shaft and hammer shaft. In the case of ball bearings, point contact is obtained. In the case of roller bearings, line contact is obtained. The area of contact is thus close to zero as opposed to a relatively large area in engagement systems using toothed surfaces. Use of point or line contact reduces heat generation and reduces energy loss due to friction.
    Type: Grant
    Filed: June 18, 2002
    Date of Patent: February 3, 2004
    Inventor: Bob B. Ha
  • HAMMER DRILL
    Publication number: 20030230422
    Abstract: A hammer drill with rolling contact at the contact surfaces for transmission of axial force between a drive shaft and hammer shaft. In the case of ball bearings, point contact is obtained. In the case of roller bearings, line contact is obtained. The area of contact is thus close to zero as opposed to a relatively large area in engagement systems using toothed surfaces. Use of point or line contact reduces heat generation and reduces energy loss due to friction.
    Type: Application
    Filed: June 18, 2002
    Publication date: December 18, 2003
    Inventor: Bob B. Ha