Patents by Inventor Tomoyoshi Hirazuka

Tomoyoshi Hirazuka 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).

  • Patent number: 3933023
    Abstract: A method for manufacturing a unit piece for a `V` pulley of the type in which a pair of unit pieces of the same configuration are assembled in back-to-back relation to each other into a single complete pulley, said unit piece having a central flat portion and a circumferential `V` groove forming portion continuous with the flat portion, characterized by the steps of preparing a forging stock of a disk form of which the outer diameter is equal to the outer diameter D.sub.1 of said pulley unit peice and the thickness is equal to the thickness T of the flat portion of said pulley unit piece; and cold-forging said forging stock for deforming an outer circumferential portion thereof so that the thickness of the portion is gradually reduced radially outwardly to define a cylindrical portion of height L as well as an outermost circumference of thickness T.sub.1 and n innermost circumference of thickness T.sub.2 (T.sub.1 <T.sub.
    Type: Grant
    Filed: February 26, 1975
    Date of Patent: January 20, 1976
    Assignee: Hitachi, Ltd.
    Inventors: Hideo Tatsumi, Tomoyoshi Hirazuka, Hisanobu Kanamaru