Patents by Inventor Gary W. Crawford

Gary W. Crawford 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: 4360424
    Abstract: A sluice box apparatus for recovering heavy material, such as gold, comprises a fine recovery channel and a coarse recovery channel. The recovery channels have receiving ends, riffles and matting for collecting fines of the material. A hopper at the receiving end of the channels has a receiving end for aggregate, a discharge end adjacent the receiving ends of the channels, a bottom, an open top and water distributing means near the top and the discharge end for washing fines from the aggregate. A perforated plate extends substantially across the hopper near the discharge end. The plate is spaced-apart from the bottom. There is a coarse material discharge opening adjacent the coarse recovery channel for a flow of water and aggregate passing over the perforated plate to the coarse recovery channel and a fine material discharge opening between the bottom end and the perforated plate and adjacent the fine recovery channel.
    Type: Grant
    Filed: April 20, 1981
    Date of Patent: November 23, 1982
    Assignee: Norman Anthony Pearson
    Inventors: Norman A. Pearson, Gary W. Crawford