Patents by Inventor Derek W. Holmes

Derek W. Holmes 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: 9869359
    Abstract: A relief valve in a hydraulic system in a machine selectively sends pressurized oil to both a brake cooling apparatus and a cylinder used to hoist a load. A relief valve lowers pressure spikes in a brake cooling line by dumping fluid in a brake cooling line to tank responsive to a pressure spikes at the head end of the cylinder during hoisting or other transitions in the hydraulic system. Reducing the pressure spikes in the brake cooling line improves reliability of the brake cooling apparatus by protecting seals from undue stresses.
    Type: Grant
    Filed: August 29, 2014
    Date of Patent: January 16, 2018
    Assignee: Caterpillar Inc.
    Inventors: Carl McIlheran, Andrew J. Kleitsch, John C. Vacca, Daniel Mather, Michael D. Hudson, Derek W. Holmes
  • Publication number: 20160061280
    Abstract: A relief valve in a hydraulic system in a machine selectively sends pressurized oil to both a brake cooling apparatus and a cylinder used to hoist a load. A relief valve lowers pressure spikes in a brake cooling line by dumping fluid in a brake cooling line to tank responsive to a pressure spikes at the head end of the cylinder during hoisting or other transitions in the hydraulic system. Reducing the pressure spikes in the brake cooling line improves reliability of the brake cooling apparatus by protecting seals from undue stresses.
    Type: Application
    Filed: August 29, 2014
    Publication date: March 3, 2016
    Applicant: CATERPILLAR INC.
    Inventors: Carl McIlheran, Andrew J. Kleitsch, John C. Vacca, Daniel Mather, Michael D. Hudson, Derek W. Holmes
  • Publication number: 20140346854
    Abstract: A braking system for a machine including an accumulator configured to receive a pressurized fluid for storage thereof. A control valve disposed between the accumulator and the brake cylinder, the control valve configured to selectively allow discharged pressurized fluid from the accumulator to a brake cylinder. A pressure sensor disposed upstream of the control valve. Further, a controller configured to determine a pressure change in the accumulator using the pressure sensor during at least one of the pulsations of the control valve and compare the determined pressure change with a pre-determined threshold.
    Type: Application
    Filed: May 23, 2013
    Publication date: November 27, 2014
    Applicant: CATERPILLAR GLOBAL MINING LLC
    Inventors: Brian D. Horton, Harold D. Dabbs, Derek W. Holmes, Jason D. Martin