Patents by Inventor David J. Lomax

David J. Lomax 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: 11946225
    Abstract: One embodiment of a hydraulic system for a machine has a first hydraulic circuit including a first pump coupled to a first hydraulic actuator configured to move a first implement of the machine. A second hydraulic circuit includes a second pump coupled to a second hydraulic actuator configured to move a second implement. An electric motor mechanically couples to the first pump and to the second pump. An operator interface receives input from an operator requesting movement of the first and second implements. A controller communicatively coupled to the electric motor and to the operator interface determines, based on the requested movement of the first and second implements respectively, first and second flow allocations respectively for the first and second pumps and determines respective target displacements for the first and second pumps.
    Type: Grant
    Filed: May 28, 2021
    Date of Patent: April 2, 2024
    Assignee: Caterpillar Inc.
    Inventors: Kalpeshkumar N Patel, Darren A Blum, Aleksandar M Egelja, Barrett A Flinn, Ryan P McEnaney, Trung Q Nguyen, David J Lomax
  • Publication number: 20220381006
    Abstract: One embodiment of a hydraulic system for a machine has a first hydraulic circuit including a first pump coupled to a first hydraulic actuator configured to move a first implement of the machine. A second hydraulic circuit includes a second pump coupled to a second hydraulic actuator configured to move a second implement. An electric motor mechanically couples to the first pump and to the second pump. An operator interface receives input from an operator requesting movement of the first and second implements. A controller communicatively coupled to the electric motor and to the operator interface determines, based on the requested movement of the first and second implements respectively, first and second flow allocations respectively for the first and second pumps and determines respective target displacements for the first and second pumps.
    Type: Application
    Filed: May 28, 2021
    Publication date: December 1, 2022
    Applicant: Caterpillar Inc.
    Inventors: Kalpeshkumar N. Patel, Darren A. Blum, Aleksandar M. Egelja, Barrett A. Flinn, Ryan P. McEnaney, Trung Q. Nguyen, David J. Lomax
  • Patent number: 10774850
    Abstract: A hydraulic system for a machine includes a first pump, an implement pump, a control valve, and an auxiliary circuit. The first pump is configured to supply a first fluid flow to a first circuit, such as a steering circuit. The implement pump is configured to supply a second fluid flow to an implement circuit to actuate a primary implement function. The auxiliary circuit is configured to deliver fluid flow to actuate an auxiliary implement function. The auxiliary circuit is fluidly coupled to the implement circuit. The auxiliary circuit is also coupled to the first circuit by the control valve. The control valve is located downstream, in the direction of fluid flow, of the implement pump and the first pump. The control valve is configured to allow at least a portion of the first fluid flow to enter the auxiliary circuit and be delivered to the auxiliary implement function.
    Type: Grant
    Filed: April 19, 2018
    Date of Patent: September 15, 2020
    Assignee: Caterpillar Inc.
    Inventors: Steven J. Juricak, David J. Lomax, Paul A. Rousseau
  • Publication number: 20190323525
    Abstract: A hydraulic system for a machine includes a first pump, an implement pump, a control valve, and an auxiliary circuit. The first pump is configured to supply a first fluid flow to a first circuit, such as a steering circuit. The implement pump is configured to supply a second fluid flow to an implement circuit to actuate a primary implement function. The auxiliary circuit is configured to deliver fluid flow to actuate an auxiliary implement function. The auxiliary circuit is fluidly coupled to the implement circuit. The auxiliary circuit is also coupled to the first circuit by the control valve. The control valve is located downstream, in the direction of fluid flow, of the implement pump and the first pump. The control valve is configured to allow at least a portion of the first fluid flow to enter the auxiliary circuit and be delivered to the auxiliary implement function.
    Type: Application
    Filed: April 19, 2018
    Publication date: October 24, 2019
    Applicant: CATERPILLAR INC.
    Inventors: Steven J. Juricak, David J. Lomax, Paul A. Rousseau
  • Patent number: 10233951
    Abstract: A system and method for detecting uncommanded positioning of at least one valve spool in a plurality of valve spools and for stopping fluid flow to a plurality of hydraulic actuators fluidly connected to the plurality of valve spools is disclosed. The method may comprise receiving a signal fluid pressure detected in a signal passageway, identifying whether at least one activation command is currently enabled, and stopping the flow of fluid to the plurality of hydraulic actuators if no activation command is enabled for any of the plurality of valve spools, and the signal fluid pressure when detected (1) upstream of the plurality of valve spools is greater than a first threshold or (2) downstream of the plurality of valve spools is less than a second threshold.
    Type: Grant
    Filed: October 5, 2016
    Date of Patent: March 19, 2019
    Assignee: Caterpillar Inc.
    Inventors: David J. Lomax, Joshua D. Callaway
  • Publication number: 20180094650
    Abstract: A system and method for detecting uncommanded positioning of at least one valve spool in a plurality of valve spools and for stopping fluid flow to a plurality of hydraulic actuators fluidly connected to the plurality of valve spools is disclosed. The method may comprise receiving a signal fluid pressure detected in a signal passageway, identifying whether at least one activation command is currently enabled, and stopping the flow of fluid to the plurality of hydraulic actuators if no activation command is enabled for any of the plurality of valve spools, and the signal fluid pressure when detected (1) upstream of the plurality of valve spools is greater than a first threshold or (2) downstream of the plurality of valve spools is less than a second threshold.
    Type: Application
    Filed: October 5, 2016
    Publication date: April 5, 2018
    Applicant: Caterpillar Inc.
    Inventors: David J. Lomax, Joshua D. Callaway
  • Patent number: 9068323
    Abstract: A machine is disclosed. The machine can include a frame and ground engaging propulsion elements coupled with the frame. A hydraulically actuated implement system can be coupled with the frame, and can include a linkage configured to couple with an implement, a hydraulic actuator coupled with the linkage and the frame, and a ride control and downforce control circuit configured to implement a ride control mode and a downforce control mode. The ride control mode can be configured to maintain a pressure of hydraulic fluid in the hydraulic actuator at a ride control pressure, and the downforce control mode can be configured to maintain the pressure of hydraulic fluid in the hydraulic actuator at a downforce control pressure to oppose the weight of the linkage and the implement such that the implement engages a substrate with a predetermined down force pressure which is proportionate to the downforce control pressure.
    Type: Grant
    Filed: December 20, 2012
    Date of Patent: June 30, 2015
    Assignee: Caterpillar Inc.
    Inventors: Jeremy T. Peterson, Jeffrey L. Kuehn, David J. Lomax, Michael L. Knussman
  • Publication number: 20140178164
    Abstract: A machine is disclosed. The machine can include a frame and ground engaging propulsion elements coupled with the frame. A hydraulically actuated implement system can be coupled with the frame, and can include a linkage configured to couple with an implement, a hydraulic actuator coupled with the linkage and the frame, and a ride control and downforce control circuit configured to implement a ride control mode and a downforce control mode. The ride control mode can be configured to maintain a pressure of hydraulic fluid in the hydraulic actuator at a ride control pressure, and the downforce control mode can be configured to maintain the pressure of hydraulic fluid in the hydraulic actuator at a downforce control pressure to oppose the weight of the linkage and the implement such that the implement engages a substrate with a predetermined down force pressure which is proportionate to the downforce control pressure.
    Type: Application
    Filed: December 20, 2012
    Publication date: June 26, 2014
    Applicant: Caterpillar Inc.
    Inventors: Jeremy T. Peterson, Jeffrey L. Kuehn, David J. Lomax, Michael L. Knussman