Patents by Inventor Douglas C. McRae

Douglas C. McRae 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).

  • Root crop harvester
    Patent number: 5038918
    Abstract: A root crop harvester including two endless web sections, with the first section overhanging the second section to form a step portion, and drive mechanism to vibrate the two web sections in their own planes by amounts that are unequal or can be made unequal (or equal) to suit the prevailing conditions.
    Type: Grant
    Filed: November 22, 1989
    Date of Patent: August 13, 1991
    Assignee: National Research Development Corporation
    Inventor: Douglas C. McRae
  • Soil-separating assemblies
    Patent number: 4448257
    Abstract: A potato harvester comprises a double disc share feeding potatoes to a vibrating upwardly-moving conveyor sieve 1 (FIG. 1), the operational area of which is determined by the relative positions of rollers 2 and 4. This area can be changed to deal with different soil conditions, any slack or excess amount of conveyor 1 resulting from this change being accommodated by an appropriate repositioning of the pulleys 4, 5.
    Type: Grant
    Filed: July 9, 1982
    Date of Patent: May 15, 1984
    Assignee: National Research Development Corporation
    Inventor: Douglas C. McRae