Kobelco Cranes Co., Ltd.

Mitsuo Kakeya

Kazuyuki Miyazaki

Disclosed is a crane comprising: a lower body; an upper slewing body; a counterweight unit including a plurality of wheels to travel on the ground in a turning direction equal to a slewing direction of the upper slewing body while being suspended from the upper slewing body; a steering actuator for rotating each of the wheels around a steering-rotation center axis to change the steering angle; and a steering control device for controlling the steering actuator. The steering control device includes: a slewing-identification-signal receiving section which receives a slewing identification signal for identification of the slewing direction of the upper slewing body; and an actuator operating section operates the steering actuator to orient each of the wheels to the inside of a tangent line to an orbit of the wheel at the steering-rotation center axis, based on the identified slewing direction identified from the slewing identification signal.

Crane equipped with travelable counterweight unit

At an inner circumference side of a lower ring and an upper ring, flange pars are formed respectively, and a ring-shaped clamp device is arranged at the inner circumference side, and separated at four points, into a front side, back side, left side, and right side, and divided into four divided clamps. At the separation points of front and back sides, the left and right divided clamps are rotatably connected with each other, and at the separation points of left and right sides, the front and back divided clamps are connected to cylinders respectively. By the extension/contraction operation, the front and back clamps move between joint and separation positions, and if the front and back clamps position at the joint points, predetermined spaces are formed between the divided clamps. Lock blocks to be inserted into the spaces for regulating return of the divided clamps to the separation positions are provided.

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Akashi, Japan

Mitsuo Kakeya