Patents by Inventor Karl William Stewart

Karl William Stewart 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).

  • Vacuum lifting device
    Patent number: 5752729
    Abstract: A vacuum lifting device that is particularly suitable for lifting refractory slabs used to line aluminum smelting cells incudes suction cups which engage the object to be lifted. A plurality of mechanical supports can be moved so that they extend at least partly underneath the object being lifted when the object is raised from the ground. The mechanical supports can hold the object in case of vacuum failure and improve the safety of the device. An optional automatic override can ensure that the mechanical supports are in the down position in the case of vacuum failure.
    Type: Grant
    Filed: May 29, 1996
    Date of Patent: May 19, 1998
    Assignee: Comalco Aluminium Limited
    Inventors: Christopher Luke Crozier, Brian Joseph Liston, Karl William Stewart