This hydraulic pump system includes: a hydraulic pump having a discharge flow rate that is changeable; a regulator device that adjusts the discharge flow rate of the hydraulic pump; an operation device including an operation tool; a lock switching input unit that unlocks the operation tool; an unloader valve that adjusts a discharge pressure of the hydraulic pump by changing the opening area of the unloader valve; and a control device that controls movement of the unloader valve. When a predetermined actuation condition is satisfied, the control device causes the unloader valve to reduce the opening area to increase the discharge pressure of the hydraulic pump. The regulator device increases the discharge flow rate after the control device causes an increase in the discharge pressure of the hydraulic pump. The actuation condition includes a condition that the lock switching input unit has unlocked the operation tool.

A hydraulic system may include a first actuator to control a first linkage member, a second actuator to control a second linkage member, a first primary hydraulic circuit and a first secondary hydraulic circuit that include the first actuator, a second primary hydraulic circuit and a second secondary hydraulic circuit that include the second actuator, a first pump to cause fluid to flow through the first primary hydraulic circuit and the second secondary hydraulic circuit, a second pump to cause fluid to flow through the second primary hydraulic circuit and the first secondary hydraulic circuit, and a controller. The controller may be configured to determine that an operator assistance mode is enabled, and cause closing of a first valve that controls fluid flow through the first secondary hydraulic circuit and a second valve that controls fluid flow through the second secondary hydraulic circuit.

A system and method for compensating reduced track speed because of engine droop for a work machine is disclosed. The system may comprise a frame, an attachment coupled to the frame, a ground-engaging mechanism adapted to support the frame, an engine, a motor, a track speed sensor, an engine speed sensor, and a controller. The engine may drive the ground-engaging mechanism and attachment. The engine may be coupled through a variable speed transmission to the ground-engaging mechanism and the attachment. They variable speed transmission may include a hydrostatic circuit. The controller may be adapted to send an increased transmission command signal based on a drop in the engine speed signal when the work machine engages an increased load. The increased transmission command signal may increase a motor speed to cause an increase in track speed to compensate at least a portion of the reduced track speed from the engine speed droop.

A system and method for the controlled lowering and lifting of a load are disclosed. The system and method may include operating a work machine having a hydraulic system including a hydraulic actuator for supporting a load, a first control valve in fluid communication with the actuator, and a controller for operating the first control valve. In one embodiment, the controller includes a first algorithm for operating the first control valve in a load lowering operation. When an operational fault within the hydraulic system is detected, the controller can be configured to enter into a safe lowering mode. In the safe lowering mode, the first algorithm is disabled and a pulse width modulation (PWM) current is sent from the controller to the first control valve. A user interface is provided to allow an operator to control the PWM current duty ratio to allow the load supported by the actuator to be lowered.

An attachment is attached to an upper turning body. During a normal operation, a drive means drives the attachment according to an input of an operator to a manipulation device. A sensor detects a motion of an excavator. Based on an output of the sensor, the slip suppression unit detects slip of a traveling body in an extension direction of the attachment and corrects an operation of the attachment performed by the drive means.

A compact utility loader compact utility loader comprising a frame, and a loader arm configured to support an attachment. The compact utility loader additionally comprises a first link pivotably secured to the frame, a second link pivotably secured to the frame, and an actuator configured to raise and lower the loader arm. The actuator is not simultaneously secured to both the frame and the loader arm.

A compact utility loader compact utility loader comprising a frame including a lower portion and an upper portion. A width of the lower portion is smaller than a width of the upper portion. The compact utility loader additionally comprises a first track and a second track, with each track being positioned on a side of the frame. Each of the tracks has a width of at least 7.5 inches, and the compact utility loader has an overall width of no more than 36 inches.

A lever-operated motor grader can include a front end including a pair of steerable tires connected to the front end; a rear end pivotally connected to the front end at an articulation joint, the rear end including a power source operatively coupled to at least two driven tires; a drawbar-circle-moldboard assembly having a blade, the drawbar-circle-moldboard assembly configured for moving the blade into various orientations, the blade movement controlled by a hydraulic system coupled to one or more operator-controlled levers of the motor grader; a controller; and a pressure sensor coupled to the hydraulic system of the blade to deliver to the controller a signal corresponding to a pressure of the hydraulic system; wherein the controller receives the signal corresponding to the pressure of the hydraulic system, and wherein the controller is configured to determine an application of the motor grader based on the received signal.

A wheel loader configured to reduce the traveling distance required for a raise and run operation, and reduce fuel consumption includes: an engine 3; a torque converter 41; a forward and reverse switch 62; a stepping amount sensor 610; an operation amount sensor 73; and a controller 5. The controller 5 determines whether a specific condition for specifying an operation of the lift arm 21 in an upper direction during forward travel of the vehicle body, on the basis of a forward and reverse switching signal, the stepping amount on the accelerator pedal 61, and a pilot pressure Ti pertaining to the lifting operation amount for the lift arm 21. When the specific condition is satisfied, the vehicle speed is limited by reducing the maximum rotational speed of the engine 3 in response to increase in the pilot pressure Ti.

To be capable of dealing with a machine body lifting operation or a sudden operation, while improving energy efficiency, during a boom-lowering operation, and achieving the reduction of the number of parts, in a construction machine equipped with a boom. It is configured such that a first region Y1 at which a recovery valve passage 16e is opened and a supply valve passage 16f is closed and a second region Y2 at which the recovery valve passage 16e and the supply valve passage 16f are opened, are provided at an operating position of a first boom control valve 16 during the boom lowering operation, and the first boom control valve 16 is positioned at the first region Y1 when neither a machine body lifting operation nor the sudden operation is performed during the boom-lowering operation, and at the region Y2 when the machine body lifting operation or the sudden operation is performed.