Patents by Inventor Harold M. Mackey

Harold M. Mackey 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).

  • Education device
    Patent number: 4674982
    Abstract: Blocks of three different shapes can be detachably secured to a supporting surface such as a board and can form numbers from 0 to 9 inclusive in digital format.
    Type: Grant
    Filed: February 24, 1986
    Date of Patent: June 23, 1987
    Inventor: Harold M. Mackey