Patents by Inventor Jack E. Cook, Sr.

Jack E. Cook, Sr. 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).

  • Automatic levelling and locking ladder
    Patent number: 4128139
    Abstract: In a self levelling ladder base of the type wherein each leg of the base has a rack and pinion assembly, the pinions being interconnected by a shaft, and a tab interfering with the pinions to prevent their rotation as weight is placed on the ladder, automatic locking means are provided to retain the tab in interfering engagement subsequent to the weight being removed, thereby increasing the operational safety of the ladder.
    Type: Grant
    Filed: December 7, 1977
    Date of Patent: December 5, 1978
    Inventor: Jack E. Cook, Sr.