JP2011111288A - Quay crane and method for controlling the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a quay crane in a quake-absorbing structure that permits a large quake-absorbing stroke correspondent to a large-scale earthquake motion, that is, to provide a crane with a quake-absorbing stroke of approximately &plusmn;1,000 mm in the sea land direction, that can respond to a phenomenon in which a quay is collapsed and the rail span is spread by an earthquake. <P>SOLUTION: The quay crane 1 includes a leg structure object 3 and a travelling device 4. The leg structure object 3 includes a trapezoidal link leg 2 deforming in the sea-land direction. Between a sea-side travelling device 4a and the leg structure object 3, a sea-side swing leg 20a and a sea-side link leg 21a having the upper interval wider than the lower interval, and not in parallel to each other, are installed. Between a land-side travelling device 4b and the leg structure object 3, a land-side swing leg 20b and a land-side link leg 21b having the upper interval wider than the lower interval, and not in parallel to each other, are installed. Between the sea-side link leg 21a and the leg structure object 3, and between the land-side link leg 21b and the leg structure object 3, quake-absorbing structures 22a, 22b, respectively, are installed. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a quay crane having a countermeasure against earthquakes applied to a crane or the like used for container handling at a port or an inland container terminal, and a control method thereof.

  Container terminals such as harbors and inland areas handle containers between ships and trailers by quay cranes, portal cranes, and container trailers. As an earthquake countermeasure in this container terminal, a crane provided with a seismic isolation structure and a swinging leg in a quay crane has been proposed (see, for example, Patent Documents 1 and 2).

  FIG. 8 shows an example of a quay crane with a conventional earthquake countermeasure. The quay crane 1X has a traveling device (sea side traveling device 4a, land side traveling device 4b) 4 at the lower end of the leg structure 3, and has a boom 6 and a girder 7 above. A trolley 8 travels along the boom 6 and the girder 7 so as to perform a container handling operation. Reference numeral 30 denotes a container ship.

  In this quay crane 1X, as a seismic isolation device, a seismic isolation device 22X made of an isolator made of, for example, laminated rubber is installed between the traveling device 4 and the land-side leg 10b. Moreover, the sea side rocking leg 20a is installed in the sea side leg 10a via the pin joint.

  In FIG. 9, the model of the leg part of the quay crane 1X is shown. In this model, the land-side traveling device 4b is installed at the lower end of the land-side leg 10b via the seismic isolation device 22X and the land-side sill beam 24b. This seismic isolation device 22X is an isolator made of laminated rubber. The land-side sill beam 24b is a horizontal member installed parallel to the quay (from the front to the back in FIG. 9).

  Moreover, the sea side rocking leg 20a is installed under the sea side leg 10a via the pin joint. A sea-side traveling device 4a is installed at the lower end of the sea-side swing leg 20a via a sea-side sill beam 24a. Furthermore, the sea side leg 10a and the land side leg 10b are connected by a horizontal member (also referred to as a portal tie beam) 23 installed in a direction perpendicular to the quay. At the normal time of loading and unloading containers, the seismic isolation device 22X is fixed with a shear pin or the like and is in a rigid state. Further, the sea-side swing leg 20a is in a soft state that can swing. In addition, the arrow has shown the load of the crane 1X.

In FIG. 10, the state which added the earthquake motion to the model of the quay crane 1X is shown. Due to the earthquake motion, a force in the sea-land direction (left-right direction in FIG. 10) is generated on the crane 1X. By this force, the shear pin of the seismic isolation device 22X breaks, and the seismic isolation device 22X acts. This crane 1X can absorb a horizontal deformation of about ± 300 mm in the sea-land direction.

  In order to cope with large-scale earthquakes, it is required for conventional seismic isolation devices to absorb horizontal deformation of about ± 1000 mm in the sea-land direction. In the future, there may be an increase in the demand for horizontal deformation to be absorbed, such as about ± 2000 mm in the sea-land direction. However, since the conventional seismic isolation device has a seismic isolation stroke of only about ± 300 mm, the stroke limit is reached and the seismic isolation device is not installed. Specifically, as shown in FIG. 8 of Patent Document 2, there is a risk of crane overturning. Similarly, there is a risk of crane overturning in the land side direction.

  On the other hand, even if an attempt is made to improve the conventional seismic isolation device, a spring component that satisfies the required elastic modulus and stroke amount cannot be obtained, or the device becomes large and cannot be installed at the conventional position. That is, it is difficult to cope with a large-scale earthquake with the conventional structure of the base isolation device 22X and the sea-side swing leg 20a.

JP 2001-192197 A JP 2000-44168 A

  The present invention has been made in view of the above problems, and an object thereof is to provide a crane having a base isolation structure capable of obtaining a large base isolation stroke corresponding to a large-scale ground motion. That is, to provide a crane that has a seismic isolation stroke of about ± 1000 mm in the sea-land direction and can cope with the phenomenon that the quay collapses and the rail span expands due to the earthquake.

  A quay crane according to the present invention for achieving the above-mentioned object is a quay crane having a leg structure and a traveling device, and having a trapezoidal link leg in which the leg structure is deformed in the sea-land direction. Between the traveling device and the leg structure, a sea-side swing leg and a sea-side link leg that are wider than the lower space and are not parallel are installed, and the land-side traveling device and the leg structure are installed. A land-side swing leg and a land-side link leg that are wider than the bottom distance and are not parallel to each other, between the sea-side link leg and the land-side link leg, and the leg structure, respectively. It is characterized by installing seismic isolation devices.

  With this configuration, even when an earthquake motion exceeding ± 300 mm occurs in the sea-land direction, the crane can obtain a sufficient seismic isolation effect without falling down. In other words, the deformation of the trapezoidal link leg can absorb the ground motion of a large-scale earthquake, and even if the position of the crane is displaced by the ground motion, a structure that does not fall can be achieved.

  Also, with this configuration, a crane having a seismic isolation stroke of ± 300 mm or more in the sea-land direction, desirably about ± 1000 mm can be obtained. Furthermore, a crane having a seismic isolation stroke of about ± 2000 mm can be used.

  In the above quay crane, the leg structure has a horizontal member that connects the sea side leg and the land side leg, and the sea side swing leg is disposed between the sea side traveling device and the sea side leg. Installing, installing the sea side link leg between the sea side traveling device and the horizontal member, installing a seismic isolation device between the horizontal member and the sea side link leg, and similarly, the land side The land-side swing leg is installed between the traveling device and the land-side leg, the land-side link leg is installed between the land-side traveling device and the horizontal member, and the horizontal member and the land-side member are installed. A seismic isolation device is installed between the link legs.

  With the structure in which the seismic isolation device is applied to the horizontal member, which is a large member, the degree of freedom in selecting the type and size of the structure of the seismic isolation device can be improved. That is, a seismic isolation device having a large movement distance (displacement amount) can be employed.

  In the above quay crane, the seismic isolation device uses at least one of a laminated rubber structure, a horizontal slider mechanism, a spring mechanism, and a damper mechanism.

In the quay crane described above, a lock damper mechanism is installed in the seismic isolation device, and the lock damper mechanism includes a shaft having a variable flow piston at an end, and the variable flow piston is slidably disposed therein. And having a casing filled with fluid, and under a first condition, the through hole formed in the variable flow piston is closed, the shaft is fixed to the casing, and the seismic isolation device Control is performed to prohibit displacement, and under the second condition, a through hole formed in the variable flow piston is communicated, the shaft is slidable with respect to the casing, and the seismic isolation device can be displaced freely. It is characterized by performing control.

  With this configuration, the timing at which the crane's seismic isolation device starts operating can be precisely controlled. In other words, it is possible to control the seismic isolation device to operate quickly when an earthquake motion having a magnitude exceeding a preset value occurs. Therefore, a reliable and precise seismic isolation effect can be obtained. The first condition is assumed to be a normal time when the crane performs a cargo handling operation of the container, and the second condition is assumed to be an earthquake.

  In order to achieve the above object, a quay crane control method according to the present invention is a quay crane control method having a leg structure and a traveling device, and having a trapezoidal link leg in which the leg structure is deformed in the sea-land direction. The quay crane is installed with a sea-side swing leg and a sea-side link leg between the sea-side traveling device and the leg structure, the upper part being wider than the lower part and not parallel, A land-side swing leg and a land-side link leg that are wider than the lower distance and are not parallel between the traveling device and the leg structure on the side are installed, and the sea-side link leg and the land-side link are installed. A seismic isolation device is installed between the leg and the leg structure, respectively, and under the first condition, the sea side swing leg and the land side swing leg are connected to the leg structure and the traveling device. Swinging and prohibiting displacement of the seismic isolation device Under the second condition, the sea-side swing leg and the land-side swing leg can be swung with respect to the leg structure and the traveling device, and the seismic isolation device can be freely displaced. It is characterized by performing the control. By this structure, the same effect as the quay crane which has the above-mentioned composition can be obtained.

  With the crane according to the present invention, a large seismic isolation stroke corresponding to a large-scale earthquake motion can be obtained. That is, the conventional seismic isolation device can only handle a seismic isolation stroke of about ± 300 mm, but can provide a crane that can handle a seismic isolation stroke exceeding ± 1000 mm.

It is the figure which showed the outline | summary of the crane of embodiment which concerns on this invention. It is the figure which showed the seismic isolation apparatus of the crane of embodiment which concerns on this invention. It is the figure which showed the seismic isolation apparatus of the crane of embodiment which concerns on this invention. It is the figure which showed the model of the crane of embodiment which concerns on this invention. It is the figure which showed the model of the crane of embodiment which concerns on this invention. It is the figure which showed the model of the crane of embodiment which concerns on this invention. It is the figure which showed the lock | rock type damper mechanism of the crane of embodiment which concerns on this invention. It is the figure which showed the outline | summary of the crane with the conventional seismic isolation mechanism. It is the figure which showed the model of the crane with the conventional seismic isolation mechanism. It is the figure which showed the model of the crane with the conventional seismic isolation mechanism.

Hereinafter, a crane according to an embodiment of the present invention will be described with reference to the drawings. An example of the trapezoidal link leg 2 which the crane 1 has in FIG. 1 is shown. The trapezoidal link leg 2 includes a sea side swing leg 20a extending upward (for example, in a vertical direction) from the sea side sill beam 24a on the sea side traveling device 4a toward the sea side leg 10a, and the sea side swing leg 20a. The sea side link leg 21a is inclined to the land side (left side in FIG. 1). The sea side link leg 21a is installed on a horizontal member (hereinafter referred to as portal tie beam) 23 via a sea side seismic isolation device 22a. The land side has the same structure as the sea side.

  In addition, each rocking leg 20 (the sea side rocking leg 20a, the land side rocking leg 20b) and the link leg 21 (the sea side link leg 21a, the land side link leg 21b) are rocked in the sea-land direction (the left-right direction in FIG. 1). Each end has a pin joint so that it can be moved (moved). By this link mechanism, the trapezoidal link leg 2 can be deformed in the sea-land direction.

  Next, the operation and control of the trapezoidal link leg 2 will be described. During normal operation (first condition) in which the crane 1 performs container handling work or the like, the trapezoidal link leg 2 is fixed to be in a rigid state. Specifically, the sea-side swing leg 20a and the land-side swing leg 20b are fixed to the sea-side leg 10a and the land-side leg 10b by a shear pin or the like, respectively. Similarly, the movements of the sea side seismic isolation device 22 a and the land side seismic isolation device 22 b are fixed with a shear pin or the like, and the sea side link leg 21 a and the land side link leg 21 b are fixed to the portal tie beam 23. When an earthquake occurs (second condition), the trapezoidal link leg 2 is deformed in the sea-land direction due to the breakage of a shear pin or the like.

  In addition, you may comprise so that the stopper 25 may be installed in the portal tie beam 23 and the movement range (oscillation range) of the sea side seismic isolation device 22a and the land side seismic isolation device 22b may be restrict | limited. With this configuration, it is possible to prevent the seismic isolation device 22 (22a and 22b) from moving indefinitely and causing the crane 1 to fall over even when an earthquake motion more than expected occurs. Further, the shear pin may be installed on either one of the swing leg 20 or the seismic isolation device 22.

  An example of the seismic isolation device 22 is shown in FIG. The seismic isolation device 22 is configured by combining a horizontal slider mechanism, a spring mechanism, and a damper mechanism. In addition, although description demonstrates the land side seismic isolation apparatus 22b as an example, the sea side seismic isolation apparatus 22a can also be comprised similarly. This land-side seismic isolation device 22b is installed through the pin joint 15 at the upper end of the land-side link leg 21b. The land-side seismic isolation device 22b has a roller 16 for moving on the portal tie beam 23 in the sea-land direction.

  The land-side seismic isolation device 22 b includes the spring mechanism 11 and the damper mechanism 12 between the portal tie beam 23. Further, the land-side seismic isolation device 22 b is fixed to the portal tie beam 23 by the shear pin 13. In addition, a stopper 25 is provided to limit unlimited movement of the land-side seismic isolation device 22b.

  Next, the operation of the land-side seismic isolation device 22b will be described. At the normal time when the crane 1 performs container handling or the like, the land-side seismic isolation device 22 b is provided with the shear pin 13, so that the land-side seismic isolation device 22 b is fixed to the portal tie beam 23. When an earthquake occurs, the shear pin 13 is broken, and the land-side seismic isolation device 22 b is movable with respect to the portal tie beam 23.

  This land-side seismic isolation device 22b absorbs the earthquake motion by moving in the sea-land direction so as not to transmit the earthquake motion to the crane 1. Further, the ground motion is attenuated by the spring mechanism 11 and the damper mechanism 12. Further, the seismic isolation device 22 has a force to return to the neutral point by the spring force of the spring mechanism 11 or the like. Therefore, after the earthquake, as a restoration work, it is only necessary to insert a new shear pin 13 and fix the land-side seismic isolation device 22b. At the same time, the land-side swing leg 20b and the land-side leg 10b are also fixed.

As described above, the seismic isolation device 22 (22a and 22b) is installed on the portal tie beam 23, which is a large member, so that the range of movement of the seismic isolation device 22 can be increased. That is, on the portal tie beam 23, the seismic isolation device 22 having the rollers 16 can easily move about ± 1000 mm in the sea-land direction. Therefore, the crane 1 can obtain an effective seismic isolation effect against a large-scale earthquake. In addition, restoration work after an earthquake can be easily performed.

  FIG. 3 shows a different example of the seismic isolation device 22. This seismic isolation device 22 employs a laminated rubber structure. The land-side seismic isolation device 22b is installed via the pin joint 15 at the upper end of the land-side link leg 20b. The land-side seismic isolation device 22b has a laminated rubber or an isolator constituted by a laminated rubber and steel plate.

  With the configuration in which the seismic isolation device 22 is installed on the portal tie beam 23 which is a large member, a large isolator can be installed. That is, the seismic isolation device 22 may be installed on the portal tie beam 23 and can be moved (swinged) on the portal tie beam 23. Therefore, the degree of freedom in selecting the type and size of the structure of the seismic isolation device 22 can be improved as compared with the conventional case.

  FIG. 4 shows a model of the trapezoidal link leg 2. In this model, the sea side rocker leg 20a is connected between the sea side sill beam 24a and the sea side leg 10a via the pin joint 15, and the sea side between the sea side sill beam 24a and the portal tie beam (horizontal material) 23 is connected. The link leg 21a is connected. A sea side seismic isolation device 22a is installed between the portal tie beam 23 and the sea side link leg 21a. Similarly, a land-side swing leg 20b and a land-side link leg 21b are installed.

Here, h indicates the length of the swing leg 20 (the sea side swing leg 20a and the land side swing leg 20b), and L indicates the length of the link leg 21 (the sea side link leg 21a and the land side link leg 21b). Yes. Further, _{X S} is a sea side Yuraashi 20a and sea side link leg 21a the lower end of the interval (the lower pin _{spacing), X SU0} indicates the distance of the upper end portion (upper pin spacing). Similarly, _{X L} is the lower pin spacing Rikugawa Yuraashi 20b and the land-side link legs _{21b, X LU0} shows the upper pin spacing. Although not shown in the figure below the sill beam 24 (the sea side sill beam 24a and the land side sill beam 24b), it is assumed that the traveling device 4 is installed.

FIG. 5 shows a state in which earthquake motion is applied to the model of the trapezoidal link leg 2. Due to the earthquake motion, a force in the sea-land direction (left-right direction in FIG. 5) is generated on the crane 1. This force breaks the shear pin and the seismic isolation device 22 and the swing leg 20 act. By this action, the sea side swing leg 20a and the land side swing leg 20b are inclined to the land side (left side in FIG. 5) by the angle θ, and the portal tie beam 23 is lowered by the length of δh. Further, the upper pin interval of the sea side swing leg 20a and the sea side link leg 21a is _reduced to _XSu1 , and the upper pin interval of the land side swing leg 20b and the land side link leg 21b is extended to X _Lu1 .

Next, an analysis example of the model of the trapezoidal link leg 2 shown in FIGS. 4 and 5 will be described. For example, the normal upper pin interval (X _Su0 and X _Lu0 ) is set to 2000 mm, the lower pin interval (X _S and X _L ) is set to 1000 mm, and the length h of the sea side swing leg 20a and the land side swing leg 20b is set to 8000 mm. Assume that a force is applied to the crane 1 so that the angle θ is 5 ° due to the earthquake motion.

In this case, the crane 1 moves about 700 mm in the horizontal direction. This is twice as large as the previously estimated ground motion. At this time, the pin spacing on shown in FIG. 5, each _{X Su1} about 1500 _{mm, X Lu1} of about 2900 mm. That is, the sea side seismic isolation device 22a is contracted by 500 mm, and the land side seismic isolation device 22b is displaced by 900 mm. The above values can be calculated from the following formulas 1 to 3.
(Expression 1) h−δh = h cos θ
( _Expression 2) X _Su1 = X _S -hsin θ + √ (L ² − (h−δh) ² )
(Expression 3) X _Lu1 = X _L + hsin θ + √ (L ² − (h−δh) ² )
With the above configuration, the following operational effects can be obtained. First, the crane 1 can obtain a sufficient seismic isolation effect without overturning against a ground motion exceeding ± 300 mm in the sea-land direction. That is, even when the crane 1 moves in the horizontal direction of, for example, about ± 700 mm, the displacement amount can be sufficiently absorbed by the deformation of the trapezoidal link leg 2.

  Secondly, it is possible to cope with a situation where the quay collapses due to a large-scale earthquake and the traveling rail of the crane opens 1000 to 2000 mm (referred to as “Masaki”). The crane 1 having the trapezoidal link leg 2 is not derailed even when the sea-side and land-side traveling devices 4a and 4b move 2000 mm in the directions away from each other (also in the forward state).

  FIG. 6 shows a model of a trapezoidal link leg 2A of a different embodiment. In this model, the sea side link leg 21a is installed outside the sea side swing leg 20a. The sea side seismic isolation device 22a installed at the upper end of the sea side link leg 21a is movably installed on the portal tie beam 23 installed so as to protrude from the sea side leg 10a. Similarly, a land-side swing leg 20b and a land-side link leg 21b are installed. With this configuration, it is possible to obtain the same operational effects as the model of the trapezoidal link leg 2 described above.

  FIG. 7 shows an example of the lock type damper mechanism 31 installed in the seismic isolation device 22. The lock damper mechanism 31 is installed in place of the shear pin 13 shown in FIGS. As shown in FIG. 7A, the lock damper mechanism 31 is installed so that both ends of the seismic isolation device 22 (for example, laminated rubber 14) are connected and fixed.

  FIG. 7B shows a partial cross-sectional view of the lock type damper mechanism 31. The lock-type damper mechanism 31 has a double tubular shaft 32 having a variable flow piston 33 at the end, and a casing 34 filled with a fluid such as oil. The variable flow rate piston 33 has a through hole 35, and is configured so that the opening area of the through hole 35 can be controlled.

  Specifically, the variable flow piston 33 is configured by stacking disk-shaped members each having a through hole 35. One of the disk-shaped members is rotated, and the through-holes 35 of the disk-shaped members can be communicated or closed by this rotation.

  Next, the operation of the lock damper mechanism 31 will be described. During normal operation, the through hole 35 of the variable flow rate piston 33 is closed, and control is performed so that the filled fluid does not move in the casing 34. By this control, the shaft 32 is fixed to the casing 34, so that the seismic isolation device (for example, the laminated rubber 14) is in a rigid state.

  When an earthquake occurs, the disk-shaped member is rotated to communicate with the through hole 35 of the variable flow rate piston 33. In the casing 34, the filled fluid is controlled to move freely through the through hole 35. By this control, the shaft 32 becomes slidable with respect to the casing 34, so that the seismic isolation device can swing and exhibits its effect.

  With the configuration using the lock damper mechanism 31 described above, the seismic isolation device 22 of the crane 1 can be appropriately operated. In the past, the operation of the seismic isolation device 22 was started by the breaking of the shear pin, but it was difficult to control the breaking force of the shear pin. With respect to this shear pin, the lock damper mechanism 31 can control the timing at which the seismic isolation device 22 operates, so that a reliable and precise seismic isolation effect can be obtained.

Here, you may comprise so that control of the variable flow piston 33 may be performed actively. That is, the opening area of the through hole 35 is controlled in real time based on the displacement amount of the seismic isolation device 22.
With this configuration, the sliding resistance of the variable flow piston 33 in the lock damper mechanism 31 can be controlled, so that the damping characteristic of the seismic isolation device 22 can be controlled.

  From the above, since the seismic isolation effect of the crane 1 can be improved, the earthquake resistance against a large-scale earthquake can be improved.

1 Crane (quay crane)
2 trapezoidal link leg 3 leg structure 4 traveling device 4a seaside traveling device 4b landside traveling device 10a seaside leg 10b landside leg 20 rocking leg 20a seaside rocking leg 20b landside rocking leg 21 link leg 21a seaside link leg 21b Land side link leg 22 Seismic isolation device 22a Sea side seismic isolation device 22b Land side seismic isolation device 23 Horizontal material (portal tie beam)
24 Sill Beam 24a Sea Side Sill Beam 24b Land Side Sill Beam 31 Lock Damper Mechanism 33 Variable Flow Piston 34 Casing 35 Through Hole

Claims (5)

A quay crane having a leg structure and a traveling device, the leg structure having a trapezoidal link leg that deforms in a sea-land direction,
Between the traveling device on the sea side and the leg structure, the upper gap is wider than the lower gap, and the sea-side swing leg and the sea-side link leg that are not parallel are installed,
Between the traveling device on the land side and the leg structure, an upper space is made wider than a lower space, and a land-side swing leg and a land-side link leg that are not parallel are installed,
A quay crane, wherein a seismic isolation device is installed between the sea side link leg, the land side link leg, and the leg structure. The leg structure has a horizontal member connecting the sea side leg and the land side leg;
The sea-side swing leg is installed between the sea-side traveling device and the sea-side leg, the sea-side link leg is installed between the sea-side traveling device and the horizontal member, and the horizontal member Install a seismic isolation device between the sea side link legs,
Similarly, the land-side swing leg is installed between the land-side travel device and the land-side leg, the land-side link leg is installed between the land-side travel device and the horizontal member, The quay crane according to claim 1, wherein a seismic isolation device is installed between a horizontal member and the land side link leg.   The quay crane according to claim 1 or 2, wherein the seismic isolation device uses at least one of a laminated rubber structure, a horizontal slider mechanism, a spring mechanism, and a damper mechanism. A lock type damper mechanism is installed in the seismic isolation device,
The lock type damper mechanism has a shaft having a variable flow rate piston at an end thereof, a casing in which the variable flow rate piston is slidably disposed and filled with a fluid,
Under the first condition, the through hole formed in the variable flow piston is closed, the shaft is fixed to the casing, and the displacement of the seismic isolation device is prohibited.
Under the second condition, the through-hole formed in the variable flow piston is communicated, the shaft is slidable with respect to the casing, and control is performed to freely displace the seismic isolation device. The quay crane according to any one of claims 1 to 3. A control method for a quay crane having a leg structure and a traveling device, the leg structure having a trapezoidal link leg that deforms in a sea-land direction,
The quay crane has a sea-side swing leg and a sea-side link leg that are wider than the lower part and are not parallel between the sea-side traveling device and the leg structure, Between the traveling device and the leg structure, an upper gap is made wider than a lower gap, and a land-side swing leg and a land-side link leg that are not parallel are installed, the sea-side link leg and the land-side link leg, Seismic isolation devices are installed between the leg structures,
Under the first condition, the sea-side swing leg and the land-side swing leg are prohibited from swinging with respect to the leg structure and the traveling device, and the displacement of the seismic isolation device is prohibited. And
Under the second condition, control is performed so that the sea-side swing leg and the land-side swing leg can swing with respect to the leg structure and the traveling device, and the seismic isolation device can be freely displaced. A control method for a quay crane having a trapezoidal link leg.

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