Large manipulator and hydraulic circuit arrangement for a large manipulator

A manipulator for concrete pumps, comprising:

• a boom pedestal arranged on a frame and rotatable about a vertical axis;
• an articulated boom having at least two boom arms and bearing a concrete conveying line;
• a hydraulic drive configured for pivoting at least one of the boom arms about a horizontal axis of rotation;
• the hydraulic drive having a hydraulic cylinder and a piston movably arranged therein, the piston having a piston rod connected thereto, the hydraulic cylinder having a piston-side working volume configured to be charged with hydraulic fluid and a rod-side working volume configured to be charged with hydraulic fluid;
• a hydraulic circuit configured for driving the hydraulic drive, wherein:
• in a first switching state, the hydraulic circuit connects a first working port for the feed or discharge of the hydraulic fluid via a first fluid channel to the rod-side working volume and a second working port for the feed or discharge of the hydraulic fluid via a second fluid channel to the piston-side working volume;
• in a second switching state, the hydraulic circuit separates the first working port from the first fluid channel and thereby connects the first fluid channel to the second fluid channel for the feed of hydraulic fluid from the rod-side working volume into the piston-side working volume;
• a sensor configured for acquiring an operating state variable of the manipulator, the operating state variable being one of articulated boom posture and angular position of a boom arm;
• and
• an activation assembly in communication with the sensor and configured for setting the switching state of the hydraulic circuit as a function of the operating state variable.