A system and method for retaining a linear actuator on a crane component such as a mast is disclosed. In the system a retaining mechanism is mounted on either a body of the linear actuator or the crane component and a catch is mounted to the other of the body or the crane component. Retraction of a rod of the linear actuator causes a cap on the rod to contact the retaining mechanism, which causes the retaining mechanism to move into a latched configuration securing the linear actuator.

A vehicle crane having a boom that can be luffed between a storage position and a working position within a vertical luffing plane by at least two luffing cylinders The luffing cylinders that lie opposite one another on the luffing plane, enclosing a spread angle between their longitudinal axes in the working position, and the luffing cylinders acting on the boom outside its ends. The longitudinal axis, projected onto the luffing plane, of one luffing cylinder and a vertical direction extending within the luffing plane enclose an angle of inclination there between when the boom is in the storage position to achieve a compact design, particularly when the boom is in the storage position.

The crane includes a swing brake device installed between a hydraulic motor and a control valve and having a flow restrictor; a first backpressure detector detecting a motor backpressure between the flow restrictor and one of ports of the hydraulic motor; a second backpressure detector detecting a motor backpressure between the flow restrictor and the other port of the hydraulic motor; and a control device. The control device has an external-force direction estimation unit that estimates a swing direction of an upperstructure under an external force acting on the upperstructure on the basis of a motor backpressure detected by the first backpuressure detector and a motor backpressure detected by the second backpressure during an operating state of the swing brake device. The control device has a notification control unit that causes the notification device to provide notification of the estimated swing direction of the upperstructure.

The crane includes a swing brake device installed between a hydraulic motor and a control valve and having a flow restrictor; a first backpressure detector detecting a motor backpressure between the flow restrictor and one of ports of the hydraulic motor; a second backpressure detector detecting a motor backpressure between the flow restrictor and the other port of the hydraulic motor; and a control device. The control device has an external-force direction estimation unit that estimates a swing direction of an upperstructure under an external force acting on the upperstructure on the basis of a motor backpressure detected by the first backpuressure detector and a motor backpressure detected by the second backpressure during an operating state of the swing brake device. The control device has a notification control unit that causes the notification device to provide notification of the estimated swing direction of the upperstructure.

A control system for a construction machine stops an upper swing structure at a desired swing stop angle. A main controller sets a swing stop target angle at which an upper swing structure is to be stopped. A swing stoppability determination section reads an angle signal of the upper swing structure with respect to an undercarriage and an angle of a work implement, and determines whether the swing of the upper swing structure can be stopped at the swing stop target angle. A work implement is controlled in such a manner that an extension action of the work implement in a swing radial direction is prohibited or a contraction action of the work implement in the swing radial direction is executed in response to a signal that indicates whether the swing can be stopped and that is determined by the swing stoppability determination section.

A slewing assist system for a machine having an upper body structure supported on an undercarriage structure includes a central rotation member. The central rotation member is rotatably coupled to undercarriage structure. A slip member is concentrically coupled to central rotation member and allows a relative rotational motion. At least one pin is coupled to slip member and engages slip member in expanded position such that central rotation member and slip member rotate together. A lever arm is fixedly coupled to slip member. A first end and a second end of an actuating element are coupled to lever arm and upper structure, respectively. The slewing assist system provides additional slewing assist to upper body structure by engaging slip member and central rotation member through pin. The slewing assist system assists in a first and a second rotational direction by extending and retracting second end of actuating element, respectively.

A system and method for controlling the swing of a machine is disclosed. The system may comprise a hydrostatic circuit that includes an electronic displacement control pump and a first swing motor fluidly connected in a closed loop circuit. The electronic displacement control pump configured to control the supply of fluid to the swing motor based on a final pump displacement command. The first swing motor configured to rotate the upper carriage of the machine. The hydrostatic circuit configured to control (a) an actual speed of the first swing motor when the final pump displacement command results from a requested swing motor speed and (b) a torque of the first swing motor when the final pump displacement command results from a requested swing motor torque.

A slewing control device includes an attachment information acquisition unit, an angular velocity setting unit and a slewing control unit. The attachment information acquisition unit acquires attachment information for setting the maximum slewing angular velocity based on the transverse load acting on an attachment. The angular velocity setting unit sets the maximum slewing angular velocity of an upper slewing body based on the attachment information. The slewing control unit controls a slewing drive unit such that the slewing angular velocity of the upper slewing body does not exceed the maximum slewing angular velocity set by the angular velocity setting unit.

A slewing control device includes an attachment information acquisition unit, an angular velocity setting unit and a slewing control unit. The attachment information acquisition unit acquires attachment information for setting the maximum slewing angular velocity based on the transverse load acting on an attachment. The angular velocity setting unit sets the maximum slewing angular velocity of an upper slewing body based on the attachment information. The slewing control unit controls a slewing drive unit such that the slewing angular velocity of the upper slewing body does not exceed the maximum slewing angular velocity set by the angular velocity setting unit.

A rotation control system may be provided for a material handling machine. The rotation control system may include a boom and a work tool attached to the boom. A swing motor may be capable of swinging the boom and the work tool. A work tool motor may be capable of rotating the work tool relative to the boom. An input device may generate a first signal indicative of a desired swinging of the boom and a second signal indicative of a desired rotation of the work tool. A controller may be in communication with the input device, the swing motor, and the work tool motor. The controller may be capable of actuating the work tool motor based only on the second signal during a first mode of operation and may be capable of actuating the work tool motor based on swinging of the boom during a second mode of operation.