Patents by Inventor Jon C. Knisley

Jon C. Knisley 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: 5660422
    Abstract: An adjustable lifting device for lifting a manhole casting. The device has two endpieces each having a lifting flange for engaging and lifting the manhole casting. One endpiece is extended into engagement with the casting by one or more springloaded telescoping extension arms. Once positioned, the device is lockable to prevent retraction of the extension arm(s). A slidable and lockable collar is provided for effectuating balancing of the device and casting. Each endpiece has a safety stop to prevent the device from dropping into the casting once the lifting flanges are positioned beneath the inner ledge of the casting.
    Type: Grant
    Filed: August 20, 1996
    Date of Patent: August 26, 1997
    Inventor: Jon C. Knisley