The present disclosure relates to a hydraulic control circuit for crane slewing gear having directional valves arranged in work lines and controllable separately for the inflow and outflow to the hydraulic motor for the carrying out of a rotational movement of the slewing gear, wherein an inflow valve serves the control of the oil inflow from a hydraulic pump via the work line to the hydraulic motor and an outflow valve is provided via which the hydraulic motor can be relieved to the tank, wherein the work lines are each connected via at least one check valve to a common inlet of the outflow valve to relieve the hydraulic motor independently of the direction of rotation of the slewing gear via an outflow valve into the tank.

The present disclosure relates to a hydraulic control circuit for crane slewing gear having directional valves arranged in work lines and controllable separately for the inflow and outflow to the hydraulic motor for the carrying out of a rotational movement of the slewing gear, wherein an inflow valve serves the control of the oil inflow from a hydraulic pump via the work line to the hydraulic motor and an outflow valve is provided via which the hydraulic motor can be relieved to the tank, wherein the work lines are each connected via at least one check valve to a common inlet of the outflow valve to relieve the hydraulic motor independently of the direction of rotation of the slewing gear via an outflow valve into the tank.

The present disclosure relates to a crane, in particular an offshore crane, having a slewing gear and a hydraulic slewing gear drive, wherein the slewing gear is held in its position via a holding torque applied by the hydraulic slewing gear drive, and wherein an overload safety device is provided having at least one detection means for detecting the outreach and/or the position of the crane hook and having at least one pressure relief valve, with the system pressure applied to the hydraulic slewing gear drive via at least one pressure relief valve can be regulated in dependence on the outreach and/or on the position of the crane hook.

The present disclosure relates to a crane, in particular an offshore crane, having a slewing gear and a hydraulic slewing gear drive, wherein the slewing gear is held in its position via a holding torque applied by the hydraulic slewing gear drive, and wherein an overload safety device is provided having at least one detection means for detecting the outreach and/or the position of the crane hook and having at least one pressure relief valve, with the system pressure applied to the hydraulic slewing gear drive via at least one pressure relief valve can be regulated in dependence on the outreach and/or on the position of the crane hook.

A work vehicle includes: an operation tool that is operated by an operator; and a controller that determines a target flow rate for hydraulic oil fed to a hydraulic device on a basis of the amount of operation of the operation tool. The controller calculates a bleed-off target flow rate on a basis of the flow rate of hydraulic oil fed from a hydraulic oil pump and the target flow rate for hydraulic oil fed to the hydraulic device, calculates a bleed-off throttle differential pressure on a basis of a pressure of hydraulic oil fed from the hydraulic oil pump and a pressure of hydraulic oil in a hydraulic oil tank, calculates a bleed-off target opening area on a basis of the bleed-off target flow rate and the bleed-off throttle differential pressure, and controls a hydraulic oil control valve such that the bleed-off target opening area is achieved.

A work vehicle includes: an operation tool that is operated by an operator; and a controller that determines a target flow rate for hydraulic oil fed to a hydraulic device on a basis of the amount of operation of the operation tool. The controller calculates a bleed-off target flow rate on a basis of the flow rate of hydraulic oil fed from a hydraulic oil pump and the target flow rate for hydraulic oil fed to the hydraulic device, calculates a bleed-off throttle differential pressure on a basis of a pressure of hydraulic oil fed from the hydraulic oil pump and a pressure of hydraulic oil in a hydraulic oil tank, calculates a bleed-off target opening area on a basis of the bleed-off target flow rate and the bleed-off throttle differential pressure, and controls a hydraulic oil control valve such that the bleed-off target opening area is achieved.

An obstacle detection device detects an obstacle existing in one or more monitoring areas that are set to correspond to a movable part. A state determination unit determines whether a state of the actuator is a standby state or a suspended state under circumstances where the actuator is at a stop. On determination that the state of the actuator is the standby state, a display control unit executes automatic image output that is processing for causing a display device to display a monitoring image corresponding to a monitoring area in which the obstacle is detected out of the one or more monitoring areas. On determination that the state of the actuator is the suspended state, the display control unit stops the execution of the automatic image output.

An obstacle detection device detects an obstacle existing in one or more monitoring areas that are set to correspond to a movable part. A state determination unit determines whether a state of the actuator is a standby state or a suspended state under circumstances where the actuator is at a stop. On determination that the state of the actuator is the standby state, a display control unit executes automatic image output that is processing for causing a display device to display a monitoring image corresponding to a monitoring area in which the obstacle is detected out of the one or more monitoring areas. On determination that the state of the actuator is the suspended state, the display control unit stops the execution of the automatic image output.

Provides is a crane in which the manipulation according to an operator's intention is more easily performed. The crane includes a manipulating member capable of performing at least one of an accelerator manipulation for increasing or decreasing a rotational speed of an engine and a turning manipulation of a turning body. A predetermined operation is stopped in a case where an operator is not touching the manipulating member and the predetermined operation (turning operation, traveling operation, or the like) of the crane is performed.

Provides is a crane in which the manipulation according to an operator's intention is more easily performed. The crane includes a manipulating member capable of performing at least one of an accelerator manipulation for increasing or decreasing a rotational speed of an engine and a turning manipulation of a turning body. A predetermined operation is stopped in a case where an operator is not touching the manipulating member and the predetermined operation (turning operation, traveling operation, or the like) of the crane is performed.