Patents by Inventor David P. Ratcliffe

David P. Ratcliffe 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).

  • System for checking the calibration of gravimetic feeders and belt scales
    Patent number: 5877456
    Abstract: There is provided an system and method for calibrating weigh assemblies of bulk material feeders using test chains of known weight and pitch. In particular, the present invention is a calibration checking system for a belt-type gravimetric feeder or conveyor having a weigh span section and comprises a continuous conveyor belt, at least one pair of support rollers and at least one weigh roller. A particular weigh roller is disposed under an upper strand of the conveyor belt and equidistant from each of the support rollers so that they are in planar alignment with one another. The calibration checking assembly also comprises a test chain having a chain pitch that is integrally divisible into the pitch of the weigh span section. In addition, portions of the conveyor belt on both sides of the weigh span are inclined equally at a single particular angle relative to the weigh span section.
    Type: Grant
    Filed: July 22, 1997
    Date of Patent: March 2, 1999
    Assignee: General Signal Corporation
    Inventors: John C. Homer, III, J. Ronald Walsh, David P. Ratcliffe
  • System for checking the calibration of gravimetric feeders and belt scales
    Patent number: 5686653
    Abstract: There is provided an system and method for calibrating weigh assemblies of bulk material feeders using test chains of known weight and pitch. In particular, the present invention is a calibration checking system for a belt-type gravimetric feeder or conveyor having a weigh span section and comprises a continuous conveyor belt, at least one pair of support rollers and at least one weigh roller. A particular weigh roller is disposed under an upper strand of the conveyor belt and equidistant from each of the support rollers so that they are in planar alignment with one another. The calibration checking assembly also comprises a test chain having a chain pitch that is integrally divisible into the pitch of the weigh span section. In addition, portions of the conveyor belt on both sides of the weigh span are inclined equally at a single particular angle relative to the weigh span section.
    Type: Grant
    Filed: May 9, 1996
    Date of Patent: November 11, 1997
    Assignee: General Signal Corporation
    Inventors: John C. Homer, III, J. Ronald Walsh, David P. Ratcliffe