JP5519170B2 - Mobile jib crane - Google Patents

Description

  The present invention relates to a mobile crane mounted on the tip of a telescopic boom mounted on a vehicle, and relates to a jib crane in which a jib is provided on a revolving structure and revolves around a vertical axis, and in particular, a rear part of the revolving structure. The present invention relates to a mobile jib crane that can eliminate the counterweight attached to the vehicle.

  There are various tower-like structures constructed on the ground, such as various towers, monuments, and chimneys. One of them is a tower for wind turbines, which is a column of wind turbines for wind power generation. At the top of the tower is equipped with a plurality of propeller blades (blades) supported by a horizontal axis, and generators that generate electricity by the rotation of the windmill, heavy objects such as a rotation mechanism that adjusts the direction of the windmill to the windward, and the like Nacelle is installed. Moreover, in order to improve the power generation efficiency stably, it is necessary to receive a strong wind to some extent, and it is desirable to position the top at a position as high as possible. That is, in a windmill tower, it is necessary to extend a top part to a high position as much as possible, and to support a heavy article on the top part. In order to construct this type of tower-like structure, a mobile crane such as a large crawler crane or a mobile crane (a terrain crane) is generally used.

  By the way, in order to improve power generation efficiency in a wind turbine for wind power generation, as described above, it is required to extend the top of the wind turbine tower to a high position as much as possible. For example, a nacelle or a blade at a height exceeding 100 m, It is required to install a wind turbine body such as a hub. Moreover, when the height is increased, the power generation capacity and the like are increased, the power generation equipment is enlarged, and the weight of the windmill body is increased to 50 t or more. When constructing a 100 m class windmill, it is difficult to unload only about 80 m when the loaded load is 50 t or more with an existing mobile crane, and a large crawler crane is used.

  These crawler cranes and the like have a so-called telescopic boom having a telescopic structure, and a turning body is mounted on the tip of the telescopic boom, and the jib is centered on the turning axis in the vertical direction. A turning jib crane is used.

  With reference to FIG. 3, an operation state in which the tower-like structure 2 is constructed by the conventional mobile jib crane 1 of this type will be described. The tower-like structure 2 is constructed by gradually stacking column base members 2a from the bottom. The jib crane 1 is provided with a swivel body 1a mounted on the tip of a telescopic boom 4 loaded on a crane vehicle 3, and swivels while extending to a height corresponding to the progress of construction of the tower-like structure 2. The jib 1b provided on the body 1a suspends the column base member 2a and the nacelle 5 installed on the top of the tower-like structure 2 to perform the stacking operation. Further, the swing body 1 a of the crane 1 is attached to a swing wheel 6 provided in the vicinity of the upper end portion of the boom 4, and turns by the rotation of the swing wheel 6.

  In this type of jib crane 1, a counterweight 1c is attached to the rear part of the swivel body 1a, that is, the part of the swivel body 1a opposite to the side where the jib 1b is arranged in order to stabilize the airframe during unloading work. Yes. In the construction work, it is necessary to lift the counterweight together with the revolving body 1a. Therefore, the force required for the lifting is large, and the expansion and contraction structure of the boom 4 becomes large. Moreover, the counterweight 1c has to be carried into the construction site together with the crane 1 equipment, increasing the equipment for carrying in.

  Furthermore, since the counterweight 1c is attached to the revolving structure 1a even when unloading is not performed, a large bending moment is applied to the boom 4 as a support by the counterweight 1c to counteract it. In addition, the weights of the boom 4 and the swivel body 1a are increased to increase the size.

  For this reason, a boom swing type crane in which the counterweight is omitted has been proposed (see Patent Document 1). This boom swivel crane includes an upper fixed post fixed to a tower-like structure in the middle of installation, a swivel base that is pivotally supported on the upper fixed post via a vertical swivel shaft and is swiveled by a swivel drive device, A boom mounted on a swivel so that it can be raised and lowered, and a lower fixed portion that is disposed vertically below the upper fixed post at a predetermined interval and that is formed integrally with or separate from the upper fixed post and fixed to the tower structure. A post, a lower revolving member that is pivotally assembled to the lower fixed post so as to be concentric with the vertical swivel shaft, and a frame that extends to the opposite side of the swivel base that is fixed integrally with the swivel And an inclined tension member that connects the lower swivel member and the end of the underframe on the side opposite to the swivel base.

Japanese Patent No. 2515531

  In the boom turning type crane disclosed in Patent Document 1, the moment generated by the suspension load can be canceled by the moment caused by the tension generated in the tension member, and the counterweight is to be omitted.

  However, when the suspension load by the crane increases, the tension generated by the tension member cannot sufficiently counter the suspension load, and the bending moment applied to the column depends on the suspension load and the tension of the tension member. The thing cannot be offset, and a bending moment due to the difference in the moment acts. In particular, in the construction of a wind turbine tower for wind power generation, a nacelle equipped with a rotating mechanism or the like that is installed at the top of the wind turbine tower and aligns the directivity direction of the generator and the wind turbine to the windward is installed. Moreover, in order to generate power with high efficiency by the windmill, it is required to receive a stable wind force, and therefore, it is required to install the windmill as high as possible. For this reason, it is required to extend the windmill tower to a high place, and it is preferable that the crane used for the construction of the windmill tower does not generate the bending moment applied to the support as much as possible.

  Therefore, an object of the present invention is to provide a jib crane that omits the counterweight and can suppress the bending moment applied to the support as much as possible.

As a technical means for achieving the above-mentioned object, the mobile jib crane according to the present invention has a vertical swivel shaft at the top of a column that is raised in accordance with the progress of the construction of the tower-like structure. in mobile jib crane jib on the front of the swing body is supported about is provided, as a swing axis in the horizontal direction intersecting the longitudinal direction of the jib, swingably to support the swivel member, wherein to an appropriate height of the post is provided with a guide wheel which rotates around a strut, the leading end portion of the tension cord is fixed to the rear portion of the swing body a longitudinal line of the jib, the tension cord of the intermediate portion is cooperative with the guide wheel, it is characterized in that are led proximal end portion of the tension cord to the ground.

  When the crane suspends the load, the swinging body is swung so that the jib side of the swinging body is pulled downward about the swinging shaft by the lifting load. On the other hand, tension is generated in the tension cord against the suspension load applied to the revolving structure. At this time, the moment to cause the swinging body to swing due to the suspended load and the moment due to the tension generated in the tension line are balanced, and swinging of the swinging body is prevented.

Since the tension cord is extended between the revolving structure disposed on the top of the support column and the ground, the length of the tension cable increases when the support structure is raised and the revolving structure is at a high position. On the other hand, since the revolving structure revolves around the revolving axis, the tension cable follows and revolves. At this time, the tension cord is wound around the support column, and there is a possibility that sufficient tension cannot be generated. Therefore, the guide wheel is provided so as to guide the turning of the tension cord, and the tension cord is linked to the guide wheel. It is preferable that the installation height of the guide wheel is a position where the tension cable is smoothly turned. Note that it is preferable to synchronize the rotation of the guide wheel with the turning of the revolving structure, because the tension cord extends at the shortest distance between the revolving structure and the ground, so that the tension can be reliably generated. .

  According to the jib crane according to the present invention, since the counterweight is not attached to the revolving structure, the work on the counterweight can be omitted from the lifting work of the crane, and the workability can be improved. In addition, by balancing the tension generated in the tension cord in a state where the revolving body is swung to an appropriate angle, a bending moment is not applied to the strut, and the strut and the revolving body are not enlarged.

  Moreover, according to the jib crane which concerns on invention of Claim 2, a tension | tensile_strength can be reliably produced in the said tension | tensile_strength, it can balance with a suspension load reliably, and the stability of the operation | work of a crane can be ensured.

It is a figure explaining the work state which constructs a tower-like structure with the jib crane concerning this invention. It is a figure explaining the schematic structure of the jib crane concerning this invention. It is a figure explaining the work state which builds a tower-like structure with the conventional jib crane, and is a figure corresponding to FIG.

  The jib crane according to the present invention will be specifically described below based on the preferred embodiments shown in the drawings.

  FIG. 1 is a diagram for explaining a working state in which the tower-like structure 2 is constructed by the mobile jib crane 10, and FIG. 2 is a schematic side view for explaining the jib crane 11. In addition, the same code | symbol is attached | subjected about the site | part similar to the mobile jib crane 1 shown in FIG. The swivel body 11a of the jib crane 11 is provided at the upper end of the telescopic boom 4 via a swivel wheel 6, and can swivel about a swivel axis in the vertical direction. A jib 11b is provided at the front portion of the swivel body 11a, and a wire 13 having a hook 12 attached thereto is connected to the jib 11b.

A swing mechanism 14 is interposed between the revolving body 11a and the revolving wheel 6. The swing mechanism 14 is provided with a horizontal swing shaft 14a along a direction orthogonal to the longitudinal direction of the jib 11b. The swing body 11a can swing around the swing shaft 14a. Yes.

The distal end portion of the tension cord 15 is engaged with the rear portion of the revolving body 11a on a straight line parallel to the longitudinal direction of the jib 11b. The base end portion of the tension cord 15 is connected to a traction device 3a such as a winch loaded on the crane vehicle 3, and the middle portion of the tension cord 15 has an appropriate height of the telescopic boom 4 as a support column. It is connected to the guide wheel 16 disposed at the position. The guide wheel 16 is provided on the telescopic boom 4 so as to be rotatable about the axis of the telescopic boom 4. Further, it is preferable to rotate the guide wheel 16 in synchronization with the turning of the turning body 11a.

  In the mobile jib crane according to the present invention configured as described above, when the swing body 11a swings around the swing shaft 14a due to a lifting load caused by unloading work, the moment against the swing body 11a is controlled against the moment. A tension is generated in the tension cord 15, and the swing body 11a stops in a state where the moment acting on the swing body 11a is balanced by the moment due to the suspension load. For this reason, a bending moment does not occur in the telescopic boom 4 due to the suspension load.

When the turning body 11a is turned for unloading work, the guide wheel 16 turns in synchronization with the turning body 11a, and the tension cord 15 is guided at the intermediate portion. There is no winding. For this reason, the tension generated in the tension cord 15 can be maintained, the balance with the suspension load can be reliably maintained, and the unloading operation can be performed stably.

  According to the mobile jib crane according to the present invention, the counterweight is omitted and a bending moment is not generated in the column of the jibrane, which contributes to improvement in workability of the construction work of the tower structure.

2 tower structure
2a Column base 3 Crane vehicle
3a Towing device 4 Telescopic boom (post)
5 Nacelle 6 Turning wheel
10 Mobile jib crane
11 Jib crane
11a Revolving body
11b Jib
12 hook
13 wires
14 Swing mechanism
14a Oscillating shaft
15 Tension cord
16 guide wheels

Claims (1)

In a mobile jib crane in which a jib is provided at the front of a revolving body supported around a vertical swivel axis at the top of a column that is raised according to the progress of construction of a tower-like structure related to construction ,
With the horizontal direction intersecting the longitudinal direction of the jib as a swing axis, the swivel body is swingably supported,
A guide wheel that rotates around the support column is provided at an appropriate height position of the support column,
Fixing the tip of the tension cord on the longitudinal line of the jib and at the rear of the swivel body;
Mobile jib crane, wherein the intermediate portion of the tension cord by interlocking the guide wheel, characterized in that are led proximal end portion of the tension cord to the ground.

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