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.

A method for controlling a crane component of a tower crane in proximity of obstacles at a worksite by defining a forbidden volume is disclosed. In the method a distance from the crane component to an outer surface of the forbidden volume is determined and a computing device limits movement of the crane component based on the distance from the crane component to the outer surface of the forbidden volume to avoid entering the forbidden volume with the crane component while the crane is in operation. The crane component is one or more of a boom and a hook block.

A method for controlling a crane component of a tower crane in proximity of obstacles at a worksite by defining a forbidden volume is disclosed. In the method a distance from the crane component to an outer surface of the forbidden volume is determined and a computing device limits movement of the crane component based on the distance from the crane component to the outer surface of the forbidden volume to avoid entering the forbidden volume with the crane component while the crane is in operation. The crane component is one or more of a boom and a hook block.

A shovel includes a lower traveling body, an upper turning body turnably mounted on the lower traveling body, an object monitoring device attached to the upper turning body, an attachment attached to the upper turning body, a hook attached to the attachment, and a hardware processor. The hardware processor is configured to switch the operating mode of the shovel to a crane mode based on information obtained by the object monitoring device.

In this boom slewing angle detection device, a slewing angle detecting gear is attached to an end of a shaft of a pinion gear that meshes with a ring gear formed on a slewing bearing rotatably supporting a crane boom, and the amount of rotation of the slewing angle detecting gear is detected by a slewing-angle-detecting proximity sensor. The slewing angle detecting gear is not meshed with the ring gear or the pinion gear, which compose a slewing force transmission mechanism; thus, grease, and the like, do not adhere to the slewing angle detecting gear, and external teeth for detection of the slewing angle detecting gear are not subject to wear, so accurate slewing angle detection is possible.

A crane for lifting and transporting loads includes a base frame to transfer loads onto a support surface by a plurality of contacts in contact with the surface. An arm for lifting loads is rotatable relative to the base frame around a vertical axis. The angular range of the arm around the vertical axis includes angular fields, and load sensors. Each load sensor is associated with a respective contact to detect the force on the support surface. A control system obtains, from the load sensors, the value of the force, and detects the angular field where the arm is located. The control system determines a danger condition based on the values detected by the load sensors, according to different criteria in at least two different angular fields. The control system carries out predetermined functions of the crane, if the danger condition is reached.

A crane for lifting and transporting loads includes a base frame to transfer loads onto a support surface by a plurality of contacts in contact with the surface. An arm for lifting loads is rotatable relative to the base frame around a vertical axis. The angular range of the arm around the vertical axis includes angular fields, and load sensors. Each load sensor is associated with a respective contact to detect the force on the support surface. A control system obtains, from the load sensors, the value of the force, and detects the angular field where the arm is located. The control system determines a danger condition based on the values detected by the load sensors, according to different criteria in at least two different angular fields. The control system carries out predetermined functions of the crane, if the danger condition is reached.

A crawler crane includes: a seating switch that detects whether an operator is in a driver seat; a turn angle potentiometer that detects the turn position of a boom; and a controller. The controller is provided with a boom turn restriction control unit for performing a boom turn-restricting control whereby the boom is not allowed to turn within a predetermined angular range above the driver seat on the basis of the output from the turn angle potentiometer. The boom turn restriction control unit includes a restriction-canceling unit that cancels the boom turn-restricting control performed by a turn-restricting unit if a preset restriction-canceling condition is met. The boom turn restriction control unit cancels the boom turn-restricting control if the seating switch does not detect an operator. Ease of operation and work can thus be improved in a remote operation mode and the like.

A crawler crane includes: a seating switch that detects whether an operator is in a driver seat; a turn angle potentiometer that detects the turn position of a boom; and a controller. The controller is provided with a boom turn restriction control unit for performing a boom turn-restricting control whereby the boom is not allowed to turn within a predetermined angular range above the driver seat on the basis of the output from the turn angle potentiometer. The boom turn restriction control unit includes a restriction-canceling unit that cancels the boom turn-restricting control performed by a turn-restricting unit if a preset restriction-canceling condition is met. The boom turn restriction control unit cancels the boom turn-restricting control if the seating switch does not detect an operator. Ease of operation and work can thus be improved in a remote operation mode and the like.

Provided is a display apparatus fir traveling cranes which is capable of displaying information about another traveling crane. The display apparatus for traveling cranes is equipped with: an imaging unit 20 which is mounted to the vicinity of the tip of a boom; a display unit 30 which displays an image captured by the imaging unit 20; a crane controller 40 which controls the orientation of a traveling crane; a communication unit 53 for mutually transmitting/receiving information to/from the other traveling crane; and an image controller 50 for displaying the information about the other traveling crane, received from the other traveling crane, in such a manner as to superimpose the information upon the image of the display unit.