Patents by Inventor Preston M. Campbell

Preston M. Campbell 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: 3958376
    Abstract: An extendible tower is disclosed and includes a plurality of nestable tower sections that may be raised from a telescoping, nested position to an extended position and support a load thereat. A plurality of inverted hydraulic cylinders are located within the tower sections and are also nestable in a collapsed position. Upon receipt of hydraulic pressure, the cylinders move upwardly and extend the nested tower sections. In this regard, the hydraulic cylinder group is secured at opposite ends to a base and to the upper tower section with no securement intermediate along the length thereof. Each hydraulic cylinder and each tower section is provided with means to couple the particular section or cylinder to the next adjacent section or cylinder so as to permit continued raising thereof.
    Type: Grant
    Filed: February 15, 1974
    Date of Patent: May 25, 1976
    Assignee: Zip Up, Inc.
    Inventor: Preston M. Campbell