A tensioning assembly including a primary rod and a hydraulic jack. The primary rod being positioned adjacent to a center section of the hydraulic jack. The tensioning assembly further including a frame housing anchored to the hydraulic jack. The tensioning assembly also includes a link rod connected to the primary rod and a primary adjusting and a secondary adjusting nut associated with the link rod to adjust the tension of a cable or line.

A revolution vibration suppressing method and apparatus for pump truck boom is provided. Vibration severity of the boom in the revolution direction is detected. Dynamic characteristic parameters of the boom are extracted. A control signal that can be used to control the revolving actuator to compensate the vibration severity according to the vibration severity and the dynamic characteristic parameters is calculated. The revolving actuator is driven according to the control signal to move, to suppress the revolution vibration of the boom. A revolution vibration suppression controller and a revolution vibration suppression device for a pump truck boom are provided to implement the methods. With the disclosed methods and apparatus, the vibration of a pump truck boom in the revolution direction can be suppressed, and therefore the risk of failures of the boom is decreased and the operating safety in the work is improved.

A boom vibration suppression method for concrete distributing apparatus is disclosed. The boom comprises a boom oil cylinder for respectively driving each section of the boom; the vibration suppression method comprises: detecting the variation of output force of the boom oil cylinder, and maintaining the variation of output force within the range of a preset threshold. The present invention further provides a vibration suppression controller, a vibration suppression device, and a concrete distributing apparatus that implement the method described above. The vibration of the boom is controlled directly with little time delay. The pressure of the boom oil cylinder is controlled directly and the variation of output force is maintained within a specific range; that control process is applicable to any boom posture since it has no direct relationship with the posture and dynamic characteristics of the boom.

A work machine includes a speed detection unit that detects a shaking speed in a predetermined axial direction of a suspended object suspended from a first member. Shaking of the suspended object is reduced by performing drive control to move the first member in the axial direction, based on a detection result of the speed detection unit.