A shovel includes a lower traveling body, an upper turning body turnably mounted on the lower traveling body, an attachment attached to the upper turning body, and a hardware processor on the upper turning body and configured to execute automatic control. The hardware processor is configured to stop the automatic control when information on the movement of the shovel or information on the state of a nearby machine shows an unusual tendency.

A drive system of a construction machine includes: a controller that controls a fuel injection valve, so an actual rotation speed of an engine is adjusted to a setting rotation speed; a hydraulic circuit including a boom cylinder supplied with hydraulic oil from a pump driven by the engine, configured so energy is regenerated as motive power owing to the pump being driven by pressurized oil discharged from the boom cylinder at boom lowering; and a boom operation device including a boom operation lever. At boom lowering, the controller cuts a fuel supply to the engine when a cutting condition is satisfied, which is defined to include that an operating amount of the lever is less than or equal to a first threshold, and resumes the fuel supply when the cutting condition stops being satisfied or when the actual rotation speed of the engine becomes less than a second threshold.

A system for enabling an upper swing body of construction equipment to swing freely. A working device is attached to the upper swing body to lift and move an object. A swing motor is connected to a power unit to swing the upper swing body. A controller is electrically connected to the working device and the swing motor to detect forces applied to the working device, and based on the detected forces, generating a control signal to control the swing motor so that the upper swing body swings freely. The system enables the upper swing body to swing freely to reduce energy consumption while ensuring safety when the upper swing body lifts a load.

Power machines, power sources for power machines, and methods which provide a hydraulic signal from a hydraulic system, through the swivel joint or swivel, to control a tensioning cylinder coupled to the undercarriage without requiring a modification to the swivel. In exemplary embodiments, the same hydraulic signal provided to at least one other hydraulic component on the undercarriage to control another machine function is also provided to control one or more tensioning cylinders. For example, exemplary disclosed embodiments provide the same hydraulic signal to tension a tensioning cylinder as is provided to shift one or more two-speed drive motors. This prevents or reduces the likelihood of de-tracking without requiring a change or redesign of the swivel.

A hydraulic system for recovering potential energy of a load implement of a mobile construction vehicle. The hydraulic system includes first and second actuators and control valving. The first and second actuators are configured to be coupled to the load implement for controlling raising and lowering of the load element. The control valving is operable between a first position at which, during a lowering of the load implement, the control valving directs hydraulic fluid from one of the first and second actuators to an accumulator to charge the accumulator, and a second position at which the control valving directs hydraulic fluid from the accumulator to one or more of the first and second actuators to power the one or more of the first and second actuators to raise the load element.

A drive control method of a hydraulic actuator of a construction machine includes: determining whether a rotation operation lever and a working device operation lever are operated; calculating the required pressure of a hydraulic cylinder fix a working device according to the operation amount of the rotation operation lever; calculating the required flow rates of a swing motor and the hydraulic cylinder for the working device, the required flow rates corresponding to the operation amounts of the working device operation lever and the rotation operation lever; calculating the opening areas of the first and second proportional solenoid valves of an inlet side and an outlet side by using the calculated required pressure and required flow rates of the hydraulic cylinder for the working device and the swing motor; and calculating current values to be inputted into the first and second proportional solenoid valves of the inlet side and the outlet side according to preset data values or a table in comparison with the calculated opening areas of the first and second proportional solenoid valves of the inlet side and the outlet side.

A speed compensation part included in a construction machine executes a feedback control of regulating an opening degree of a second control valve to an opening degree obtained by subtracting a correction amount from a second target opening degree of the second control valve, when a combined manipulation is performed and a preset load determination condition is satisfied. The correction amount is calculated by the speed compensation part so as to be larger as a speed difference between a first target speed and a first actual speed becomes larger, the first target speed being a target speed of a first actuator and determined on the basis of a manipulation amount of a first instructive manipulation, the first actual speed being an actual speed of the first actuator.

A work vehicle includes a traveling unit, a revolving unit disposed on an upper side of the traveling unit, a work implement disposed on the revolving unit, a revolving driver that revolves the revolving unit, a receiver, an end position setting component, a revolution position sensor, and a drive controller. The receiver directly or indirectly receives information related to a position of an object serving as a target of a revolution of the revolving unit, from the object. The end position setting component sets an end position of a revolution of the revolving unit based on information related to the position of the object. The revolution position sensor senses a revolution position of the revolving unit during a revolution. The drive controller controls the revolving driver based on the revolution position to revolve the revolving unit from a start position of a revolution to the end position.

A work vehicle includes a traveling unit, a revolving unit disposed on an upper side of the traveling unit, a work implement disposed on the revolving unit, a revolving driver that revolves the revolving unit, a receiver, an end position setting component, a revolution position sensor, and a drive controller. The receiver directly or indirectly receives information related to a position of an object serving as a target of a revolution of the revolving unit, from the object. The end position setting component sets an end position of a revolution of the revolving unit based on information related to the position of the object. The revolution position sensor senses a revolution position of the revolving unit during a revolution. The drive controller controls the revolving driver based on the revolution position to revolve the revolving unit from a start position of a revolution to the end position.

A working machine includes a traveling device having a traveling frame, a turn base plate supported on the traveling frame and configured to turn around an axis extending in a vertical direction, the turn base plate having an opening portion through which the axis extends, and a swivel joint including an outer sleeve fixed to the turn base plate, and an inner shaft inserted to the opening portion and inserted to the outer sleeve so as to rotate about the axis, the inner shaft being configured to restrictively rotate with respect to the traveling frame. The outer sleeve has a flange portion fixed to the turn base plate on a periphery of the opening portion and covering the opening portion.