JP5008281B2 - Crane seismic isolation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a base isolation supporting method and a device for a crane capable of lengthening natural period of the crane at generation of large vibration such as an earthquake while stabilizing support of the crane at usual operation, capable of avoiding synchronization of vibration of a construction structure transmitted from a stay to a mast with vibration of a crane itself and capable of suppressing rocking of the crane. <P>SOLUTION: The construction structure 12 and the mast 2 standingly provided along the construction structure 12 are connected to each other through the stays 13 in two vertical stages and the mast 2 is auxiliarily supported by the stay 13. The device is provided with a connection release means 14 for cutting the stay 13 in the upper stage and lengthen the natural period of the climbing crane 1 when horizontal acceleration applied to a climbing crane 1 becomes a predetermined value or more. <P>COPYRIGHT: (C)2007,JPO&amp;INPIT

Description

The present invention relates to a seismic isolation support device for a crane.

  Conventionally, when constructing a structure with a crane such as a climbing crane, a method of connecting the structure and the crane with a stay as a rigid body in order to prevent the crane from overturning or to reduce the swing of the crane during work. Is commonly used.

  FIG. 6 is a schematic view showing a state in which a mast is connected to a structure in a conventional climbing crane. The climbing crane 1 is connected to the top of the mast 2 to which blocks 2a can be sequentially added via an elevating unit 3. The swivel body 4 is pivotably arranged, and a jib 5 is mounted on the swivel body 4 so that it can be raised and lowered. A counter frame 6 extending rearward is integrally provided on the swivel body 4, and a suspended load is provided on the counter frame 6. A hoisting device 9 for hoisting and lowering the wire rope 8 for suspending the hook 7 and a hoisting device 11 for hoisting and lowering the wire rope 10 for raising and lowering the jib 5 are provided. Yes.

  A stay 13 having sufficient rigidity such as a steel frame material is provided between the constructed structure 12 and the mast 2, so that it can be used during an earthquake, a strong wind, or a suspended load. A swing load applied to the mast 2 of the climbing crane 1 at the time of earth cutting or the like is distributed and supported by the structure 12 via the stay 13.

In addition, by using a damper in place of the stay 13 as described above, it is possible to reduce the vibration and impact generated in the mast 2 of the climbing crane 1 from being transmitted to the structure 12 during an earthquake, a strong wind, or when a suspended load is grounded. As an example of an apparatus configured to do so, there is, for example, Patent Document 1.
JP-A-9-58975

  However, as described above, when the structure 12 and the mast 2 of the climbing crane 1 are connected by the single stay 13 or the damper, the elevating unit 3, the revolving body 4, the jib 5 and the like disposed on the mast 2 are connected. When viewed as one mass (concentrated mass) that vibrates during an earthquake or the like, the span H1 from the connection support point (ie, the height position of the stay 13) to the structure 12 of the mast 2 to the mass (concentrated mass) is constant. Therefore, the natural period of the climbing crane 1 does not change, and the vibration of the structure 12 transmitted from the stay 13 or the damper to the mast 2 synchronizes with the vibration of the climbing crane 1 itself. There was a possibility that the situation would become excessively unfavorable.

In view of such circumstances, the present invention stabilizes the support of the crane during normal operation, and can increase the natural period of the crane when a large vibration such as an earthquake occurs, and is transmitted from the stay to the mast. It is an object of the present invention to provide a crane seismic isolation support device that can prevent the vibration of the crane from synchronizing with the vibration of the crane itself and suppress the swing of the crane.

The present invention provides a seismic isolation support device for a crane in which a structure and a mast erected along the structure are connected via a plurality of upper and lower stays, and the mast is supplementarily supported by the stay. There,
An acceleration sensor for detecting horizontal acceleration acting on the crane;
When the horizontal acceleration detected by the acceleration sensor is less than the set value, the horizontal acceleration detected by the acceleration sensor is greater than or equal to the set value. In some cases, it functions as a damper, lengthens the natural period of the crane, avoids the vibration of the structure transmitted from the stay to the mast from synchronizing with the vibration of the crane itself, and tries to transmit from the structure side to the mast side. A damping means for damping the vibration, and
Said damping means,
A cylinder-type damper body that is incorporated in the uppermost stay and filled with a working fluid in a head side chamber and a rod side chamber partitioned by a piston;
A working fluid flow path connecting the head side chamber and the rod side chamber partitioned by the piston of the damper body;
A throttle provided in the working fluid flow path;
A switching valve that is provided in the middle of the working fluid flow path and can be switched between a shut-off position that shuts off the working fluid flow path and a communication position that communicates the working fluid flow path;
When the horizontal acceleration detected by the acceleration sensor is less than a set value, the switching valve is held at a shut-off position, while the horizontal acceleration detected by the acceleration sensor is greater than or equal to a set value. Is a seismic isolation support device for a crane, characterized by comprising a controller for switching the switching valve to a communication position.

According to the crane seismic isolation support device of the present invention, it is possible to lengthen the natural period of the crane when a large vibration such as an earthquake occurs while stabilizing the support of the crane during normal operation, and to transmit from the stay to the mast. It is possible to avoid the vibration of the structure to be synchronized with the vibration of the crane itself, and to obtain an excellent effect that the swing of the crane can be suppressed.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIGS. 1 and 2 are reference examples for carrying out the present invention. In the drawing, the same reference numerals as those in FIG. 6 denote the same components, and the basic configuration is the conventional one shown in FIG. However, the present embodiment is characterized in that a structure 12 and a mast 2 erected along the structure 12 are vertically arranged in a plurality of stages (see FIG. 1 and FIG. 2). In this example, the mast 2 is supplementarily supported by the stay 13 and the horizontal acceleration acting on the climbing crane 1 becomes equal to or higher than a set value. In the example shown in the figure, the upper stay 13 is separated, and the connection releasing means 14 for extending the natural period of the climbing crane 1 is provided.

  In the case of the illustrated example, as shown in FIG. 2, the connection release means 14 is connected to the structure 12 and the upper stay so as to be broken by a shearing force when the horizontal acceleration acting on the climbing crane 1 exceeds a set value. 13 and a shear pin 15 that connects to 13. The mast 2 side of the upper stay 13 is connected by a normal pin (not shown) that does not break even when the horizontal acceleration acting on the climbing crane 1 exceeds a set value. Contrary to the above, the structure 12 side of the upper stay 13 is connected by a normal pin that does not break even if the horizontal acceleration acting on the climbing crane 1 exceeds a set value, and the upper stay 13 It goes without saying that the connection releasing means 14 may be configured by connecting the mast 2 side with a shear pin that is broken by a shearing force when the horizontal acceleration acting on the climbing crane 1 becomes a set value or more.

  Next, the operation of the illustrated example will be described.

  During normal operation, the mast 2 erected along the structure 12 is connected to the structure 12 via two upper and lower stays 13, so that the climbing crane 1 is supported in an extremely stable state.

  On the other hand, when the horizontal acceleration acting on the climbing crane 1 exceeds a set value when a large vibration such as an earthquake occurs, the shear pin 15 (see FIG. 2) that connects the structure 12 and the upper stay 13 is shearing force. And the upper stay 13 is cut off, and the span from the connection support point of the mast 2 to the structure 12 to the mass (concentrated mass) is increased from H1 to H2, so that the natural period of the climbing crane 1 is increased. It can be made longer.

Here, the seismic response analysis result of the climbing crane 1 is as shown in FIG. 3, and the excessive input seismic wave (the maximum value of the input acceleration α is approximately 1240 [gal]: 1 [gal] as shown in FIG. ] = 1 [cm / sec ² ]) is applied to the climbing crane 1, and if the span is set to H1 = 42.1 [m] by leaving the upper stay 13 without being cut off, the mass response The acceleration β1 is as shown in FIG. 3B, and the maximum value of the response acceleration β1 is about 517 [gal], and the natural period of the climbing crane 1 is T1 = 2.51 [sec].
On the other hand, when the span is set to H2 = 62.1 [m] by separating the upper stay 13, the mass response acceleration β2 is as shown in FIG. The maximum value of β2 is approximately 361 [gal], and the natural period of the climbing crane 1 is T2 = 4.64 [sec].
It has been confirmed that

That is, the ratio of the maximum value of the response acceleration β2 to the maximum value of the response acceleration β1 is
361/517 ≒ 0.698
As described above, the maximum value of the response acceleration can be reduced by about 30% by separating the upper stay 13 when a large vibration such as an earthquake occurs, and the natural period of the climbing crane 1 is further reduced. The vibration of the structure 12 transmitted from the stay 13 to the mast 2 becomes out of synchronization with the vibration of the climbing crane 1 itself, with the increase of 4 to 5 [sec].
β2 (maximum value) / α (maximum value) = 361 / 1240≈0.291
Thus, the response acceleration is reduced to about 30 [%] of the input acceleration, and the climbing crane 1 is not excessively shaken, and damage due to an earthquake or the like can be minimized.

  In this way, the natural cycle of the climbing crane 1 can be lengthened when a large vibration such as an earthquake occurs while stabilizing the support of the climbing crane 1 during normal operation, and the structure 12 transmitted from the stay 13 to the mast 2 can be increased. It can avoid that a vibration synchronizes with the vibration of climbing crane 1 itself, and can suppress the swing of climbing crane 1.

4 and 5 show an example of an embodiment of the present invention. In the figure, the same reference numerals as those in FIG. 6 denote the same components, and the basic configuration is the conventional one shown in FIG. 4 and FIG. 5, the feature of the illustrated example is that a structure 12 and a mast 2 erected along the structure 12 are vertically arranged in a plurality of stages (see FIG. In this example, the revolving body 4 is provided with an acceleration sensor 16 which is connected via a stay 13 of two stages) and supports the mast 2 by the stay 13 and detects horizontal acceleration acting on the climbing crane 1. When the horizontal acceleration detected by the acceleration sensor 16 is less than the set value, it acts as a rigid body, while when the horizontal acceleration detected by the acceleration sensor 16 exceeds the set value, the damper Serves as a climbing Attenuating means 17 for increasing the natural period of lane 1 and attenuating vibration to be transmitted from the structure 12 side to the mast 2 side is incorporated in the stay 13 of the uppermost stage (the upper stage in the example in the figure). .

In the illustrated example, the attenuating means 17 is as shown in FIG.
A cylinder-type damper main body 21 in which a head side chamber 19 and a rod side chamber 20 which are incorporated in the upper stay 13 and partitioned by a piston 18 are filled with a working fluid such as oil;
A working fluid flow path 22 connecting the head side chamber 19 and the rod side chamber 20 partitioned by the piston 18 of the damper main body 21;
A throttle 23 provided in the working fluid flow path 22;
An electromagnetic switching valve 26 that is provided in the middle of the working fluid flow path 22 and can be switched between a blocking position 24 for blocking the working fluid flow path 22 and a communication position 25 for communicating the working fluid flow path 22;
When the horizontal acceleration detected by the acceleration sensor 16 is less than the set value, the switching valve 26 is held at the cutoff position 24, while the horizontal acceleration detected by the acceleration sensor 16 is equal to or greater than the set value. When this happens, the switching valve 26 is constituted by a controller 27 for switching to the communication position 25.

  An auxiliary tank (not shown) in which a working fluid such as oil is stored is connected to the rod side chamber 20 of the damper main body 21, and an amount corresponding to the working fluid leaking from the damper main body 21 to the outside. The working fluid can be appropriately replenished from the auxiliary tank.

  When configured as described above, when the horizontal acceleration acting on the climbing crane 1 is detected by the acceleration sensor 16 and the horizontal acceleration detected by the acceleration sensor 16 is less than the set value, the switching valve 26 is As shown in FIG. 5, a working fluid such as oil cannot flow through the working fluid flow path 22 that connects the head side chamber 19 and the rod side chamber 20 that are held at the shut-off position 24 and partitioned by the piston 18 of the damper main body 21. The damper body 21 constituting the means 17 works as a rigid body. That is, during normal operation, as in the example shown in FIGS. 1 and 2, the mast 2 erected along the structure 12 is connected to the structure 12 via the stays 13 as upper and lower two-stage rigid bodies. Because of its shape, the climbing crane 1 is supported in an extremely stable state.

  On the other hand, when a large vibration such as an earthquake occurs and the horizontal acceleration detected by the acceleration sensor 16 exceeds a set value, the solenoid of the electromagnetic switching valve 26 is excited by a control signal from the controller 27. Then, the switching valve 26 is switched from the shut-off position 24 shown in FIG. 5 to the communication position 25, and oil is supplied to the working fluid flow path 22 connecting the head side chamber 19 and the rod side chamber 20 partitioned by the piston 18 of the damper main body 21. Therefore, the damper main body 21 functions not as a rigid body but as an original damper, so that, as in the example shown in FIG. It becomes possible to lengthen the natural period, and furthermore, vibrations that are transmitted from the structure 12 side to the mast 2 side have viscosity such as oil. The flow resistance when passing through the dynamic fluid restrictor 23, it is possible to more effectively attenuated.

  In this way, the natural cycle of the climbing crane 1 can be lengthened when a large vibration such as an earthquake occurs while stabilizing the support of the climbing crane 1 during normal operation, and the structure 12 transmitted from the stay 13 to the mast 2 can be increased. It is possible to more effectively avoid the vibration from synchronizing with the vibration of the climbing crane 1 itself by using the damper main body 21, and the swing of the climbing crane 1 can be more efficiently suppressed.

The seismic isolation support device for a crane according to the present invention is not limited to the illustrated example described above, and it is needless to say that various changes can be made without departing from the gist of the present invention.

It is the schematic which shows the reference example of the form which implements this invention. It is a principal part enlarged view which shows the connection part of the stay and structure in the reference example of embodiment which implements this invention, Comprising: It is the II section equivalent view of FIG. It is a diagram which shows the seismic response analysis result of a climbing crane, (a) is a diagram which shows an input seismic wave (input acceleration alpha), (b) is from a connection support point to a mass (concentrated mass) to a mast structure. Diagram showing the response acceleration β1 of the mass when the span is H1, (c) shows the response acceleration β2 of the mass when the span from the connection support point to the mass (concentrated mass) for the mast structure is H2. FIG. It is the schematic which shows an example of the form which implements this invention. It is a circuit diagram showing a damping means in an example of the mode for carrying out the present invention. It is the schematic which shows the state which connected the mast with respect to the structure in the conventional climbing crane.

Explanation of symbols

1 Climbing crane (crane)
2 Mast 12 Structure 13 Stay 14 Connection release means 15 Shear pin 16 Acceleration sensor 17 Damping means 18 Piston 19 Head side chamber 20 Rod side chamber 21 Damper body 22 Working fluid flow path 23 Restriction 24 Shut off position 25 Communication position 26 Switching valve 27 Controller H1 Span H2 span

Claims (1)

A seismic isolation support device for a crane, in which a structure and a mast erected along the structure are connected via a plurality of upper and lower stays, and the mast is supplementarily supported by the stay,
An acceleration sensor for detecting horizontal acceleration acting on the crane;
When the horizontal acceleration detected by the acceleration sensor is less than the set value, the horizontal acceleration detected by the acceleration sensor is greater than or equal to the set value. In some cases, it functions as a damper, lengthens the natural period of the crane, avoids the vibration of the structure transmitted from the stay to the mast from synchronizing with the vibration of the crane itself, and tries to transmit from the structure side to the mast side. A damping means for damping the vibration, and
Said damping means,
A cylinder-type damper body that is incorporated in the uppermost stay and filled with a working fluid in a head side chamber and a rod side chamber partitioned by a piston;
A working fluid flow path connecting the head side chamber and the rod side chamber partitioned by the piston of the damper body;
A throttle provided in the working fluid flow path;
A switching valve that is provided in the middle of the working fluid flow path and can be switched between a shut-off position that shuts off the working fluid flow path and a communication position that communicates the working fluid flow path;
When the horizontal acceleration detected by the acceleration sensor is less than a set value, the switching valve is held at a shut-off position, while the horizontal acceleration detected by the acceleration sensor is greater than or equal to a set value. Comprises a controller for switching the switching valve to the communication position.

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