Patents Assigned to Grizzly Corporations
  • Patent number: 4483084
    Abstract: A trencher machine for attachment to a tractor movably mounted hydraulically for up and down movement relative thereto, boom means for adjusting the depth of the cut in the soil, boom means pivotally mounted on a support means including cutting means thereon.
    Type: Grant
    Filed: June 9, 1982
    Date of Patent: November 20, 1984
    Assignee: Grizzly Corporations
    Inventors: Robert H. Caldwell, Randy J. Scott
  • Patent number: 4156466
    Abstract: An apparatus mounting on the main frame of a motorgrader for controlling grading and sloping of road shoulders and previously subgraded surfaces having a resilient suspension system for the moldboard depending from the main frame of the grader which is laterally spaced from the point of application of a control load by a universally-connected, double-acting hydraulic jack attached thereto; said moldboard being lifted against said resilient support relative to the main frame of the grader for grade control by a shoe, wheel or ski, which is mounted adjacent the one end thereof and arranged for sliding along a roadway or other previously graded surface as a horizontal reference, and tilted relative to the main frame for slope control by manipulation of the double-acting hydraulic jack controlled by a feedback controller which measures the error in actual moldboard tilt and compares it to a fixed vertical reference as determined by a pendulous sensor and corrects the same in establishing the desired slope to the
    Type: Grant
    Filed: January 20, 1978
    Date of Patent: May 29, 1979
    Assignee: Grizzly Corporation
    Inventor: Robert H. Caldwell