Abstract: A cushion arrangement for smoothing stage changes in an hydraulic cylinder and including at least one compression chamber of variable volume with a movable and/or deformable chamber wall element displaceable by at least one of the pistons when approaching the transition zone between first and second stages of displacement. The compression chamber is operatively connected to a gas volume to be compressed upon displacement of the chamber wall element.
Type:
Grant
Filed:
March 14, 2012
Date of Patent:
October 6, 2015
Assignee:
Liebherr-Mining Equipment Company
Inventors:
Bryan Michael Harper, James Arthur Whitfield, Jr.
Abstract: The present invention relates to a method and an apparatus for controlling the drive system for mobile equipment, when the operator's drive commander is kept constant, electric traction motors are controlled by a torque controller to provide uniform torque, deviations in speeds of the electric traction motors are determined and electric motor power of at least one is varied relatively to the electric motor power of the other in response to a determined deviation in speed to keep the torques uniform. The power control balancing compensates for the torque differences previously encountered when the speeds of the traction motors differ at equal power supplied to the traction motors.
Abstract: A cushion arrangement for smoothing stage changes in an hydraulic cylinder and including at least one compression chamber of variable volume with a movable and/or deformable chamber wall element displaceable by at least one of the pistons when approaching the transition zone between first and second stages of displacement. The compression chamber is operatively connected to a gas volume to be compressed upon displacement of the chamber wall element.
Type:
Application
Filed:
March 14, 2012
Publication date:
October 11, 2012
Applicant:
Liebherr-Mining Equipment Company
Inventors:
Bryan Michael Harper, James Arthur Whitfield, JR.
Abstract: The present invention relates to a method and an apparatus for controlling the drive system for mobile equipment, when the operator's drive commander is kept constant, electric traction motors are controlled by a torque controller to provide uniform torque, deviations in speeds of the electric traction motors are determined and electric motor power of at least one is varied relatively to the electric motor power of the other in response to a determined deviation in speed to keep the torques uniform. The power control balancing compensates for the torque differences previously encountered when the speeds of the traction motors differ at equal power supplied to the traction motors.