{Technical Field}

{0001}

The present invention relates to a crane wherein a gantry-traveling device travels along a rail or rails to move a crane body.

{Background Art}

{0002}
A container crane is a bridge crane installed at a quay of a container terminal, is equipped with hoisting beams for handling containers, and movably travels on a track or tracks (a rail or rails) . The traveling of the container crane on the rail is carried out by a gantry traveling device including wheels and others. The container crane is secured to the rail or the ground by a gantry anchoring device so as to prevent the crane from traveling along the rail when the crane operates while its traveling is stopped, or when the operation is halted because of blast of wind or the like.

{0003}
The gantry anchoring device includes a rail clamp that grips the rail, an apparatus for pushing against a top face of the rail (also referred to as a "rail brake" hereinafter) , a mechanical brake or an electric motor brake with respect to the wheels, and an anchoring device that can be secured to the ground, etc.

{0004}
In some cases, the container crane may be provided with a seismic isolation system between the crane body and the gantry traveling device in order to prevent the crane from falling down due to an earthquake. Patent Literature 1 discloses a technique relating to a seismic isolation system for preventing the wheels of the crane from running off the rail due to an earthquake.

{Citation List}

{Patent Literature}

{0005}

{Patent Literature 1} The Publication of Japanese Patent No. 3941633

{Summary of Invention}

{Technical Problem}

{0006}
One of the causes of falling down of a container crane due to an earthquake may be the wheels of the container crane running off the rail because the wheels float up due to seismic force applied in the direction perpendicular to the gantry traveling direction (the direction perpendicular to the rail-extending direction). On that account, a seismic isolation system provided between the crane body and the gantry traveling device reduces the seismic force in the direction perpendicular to the gantry traveling direction so as to prevent the wheels of the container crane from running off the rail.

{0007}
To the contrary, with respect to seismic force in the gantry traveling direction (the direction parallel to the rail-extending direction), not the seismic isolation system but sliding friction between the gantry traveling device (the wheels) of the container crane and the rail or friction of a brake provided at a wheel drive unit absorbs and alleviates vibrations. If the container crane is not secured to the rail or the ground by the gantry anchoring device while the crane is traveling or in other states, the movable range of the gantry traveling device is not restricted; however, if the container crane stops its traveling and is secured, the movement of the gantry traveling device is restricted, and thereby vibrations cannot be absorbed and alleviated sufficiently. Consequently, a great impact is applied to the container crane and damage may be caused to the crane.

{0008}
A rail clamp included in the gantry anchoring device is connected to the gantry traveling device through a connecting member. The connecting member is provided with a shear pin, and when predetermined seismic force acts in the gantry traveling direction, the shear pin becomes broken off. Therefore, until the shear pin becomes broken off, the crane resists to the slide in the gantry traveling direction by use of the rail clamp. After the shear pin is broken off, a seismic isolation effect is generated by sliding friction between the wheels and the rail, or the like, but the rail clamp is still secured to the rail. Hence, depending on the traveling distance of the crane on the rail, the gantry traveling device may come in contact with the rail clamp, which may cause damage to the rail clamp, resulting in a great disadvantage to a recovery operation.

{0009}
The present invention has been made in view of the above-mentioned circumstances, and has an object to provide a crane capable of reliably attaining a seismic isolation effect also with respect to seismic force in the direction parallel to the extending direction of the rail when an earthquake occurs.

{Solution to Problem}

{0010}
In order to solve the above problems, the crane of the present invention employs the following solutions.
A crane according to a first aspect of the present invention comprises a crane body, a gantry traveling device that travels along a rail to move the crane body, a gantry anchoring device for securing the gantry traveling device to the rail so as to prevent the gantry traveling device from traveling along the rail, a detection unit for detecting seismic force, and a release unit for releasing the gantry traveling device secured to the rail by the gantry anchoring device when the detection unit detects the seismic force.

{0011}
According to the first aspect, the gantry traveling device travels along the rail and thereby the crane body moves, and the gantry traveling device is secured to the rail by the gantry anchoring device so as to prevent the gantry traveling device from traveling along the rail when the crane operates while its traveling is stopped, or when the operation is halted, for example. Then, the release unit releases the gantry traveling device secured to the rail by the gantry anchoring device when the detection unit detects the seismic force. As a result, when an earthquake occurs, the gantry traveling device can move along the rail, and a seismic isolation effect with respect to the seismic force in a direction parallel to the extending direction of the rail can be attained by the gantry traveling device and the rail.

{0012}
The gantry anchoring device described herein includes a gantry anchoring device provided separately from the gantry traveling device (for example, a rail clamp, an apparatus for pushing against a top face of a rail, etc.) or a gantry-anchoring device provided for the gantry traveling device (a mechanical brake or an electric motor brake with respect to the wheels, etc.). Alternatively, the gantry anchoring device may be an anchoring device for securing the crane body to the ground. The detection unit is a seismometer or the like for detecting vibrations due to the seismic force.

{0013}
In the above-described first aspect, the crane may further comprise a seismic isolation system provided between the crane body and the gantry traveling device, so as to reduce the seismic force input into the crane body in a direction perpendicular to the extending direction of the rail, and the seismic isolation system starts to operate when the detection unit detects the seismic force.

{0014}
According to the above configuration, the seismic isolation system is provided between the crane body and the gantry traveling device, and the seismic isolation system starts to operate when the detection unit detects the seismic force, thereby reducing the seismic force input into the crane body in the direction perpendicular to the extending direction of the rail. As a result, when an earthquake occurs, a seismic isolation effect can be attained not only with respect to the seismic force in the direction parallel to the extending direction of the rail, but also with respect to the seismic force in the direction perpendicular to the extending direction of the rail.

{0015}
In the above configuration, the crane may further comprise a suppression unit for suppressing an operation of the seismic isolation system under a normal condition and releasing the suppressed operation of the seismic isolation system in response to the input of the seismic force in the direction perpendicular to the extending direction of the rail, and the detection unit detects that the operation of the seismic isolation system suppressed by the suppression unit is released.

{0016}
According to the above configuration, in the normal state where no earthquake occurs, the suppression unit suppresses the operation of the seismic isolation system. On the other hand, when the seismic force in the direction perpendicular to the extending direction of the rail is input at the time of occurrence of the earthquake, the operation of the seismic isolation system suppressed by the suppression unit is released and the seismic isolation system starts to operate. When the detection unit detects that the suppressed operation of the seismic isolation system is released, the detection unit detects the seismic force, and the gantry traveling device secured to the rail by the gantry anchoring device is released. Therefore, the seismic isolation effect with respect to the seismic force in the direction perpendicular to the extending direction of the rail is attained by the seismic isolation system released from the suppressed state, while the seismic isolation effect with respect to the seismic force in the direction parallel to the extending direction of the rail can also be attained.

{0017}
A crane according to a second aspect of the present invention comprises a crane body, a gantry traveling device that travels along a rail to move the crane body, a seismic isolation system provided between the crane body and the gantry traveling device, a gantry anchoring device provided separately from the gantry traveling device and secured to the rail in order to secure the crane body so as to prevent the crane body from traveling along the rail, a connecting place for coupling the gantry traveling device and the gantry anchoring device under a normal condition and releasing the coupling between the gantry traveling device and the gantry anchoring device in response to an input of seismic force in a direction perpendicular to an extending direction of the rail, a suppression unit for suppressing an operation of the seismic isolation system in the normal state, a detection unit for detecting the seismic force by detecting that the coupling between the gantry traveling device and the gantry anchoring device through the connecting place is released, a first release unit for releasing the gantry anchoring device secured to the rail when the detection unit detects the seismic force, and a second release unit for releasing the operation of the seismic isolation system suppressed by the suppression unit when the detection unit detects the seismic force.

{0018}
According to the above second aspect, while the gantry traveling device travels along the rail and thereby the crane body moves, the gantry anchoring device is secured to the rail so as to prevent the gantry traveling device from traveling along the rail when the crane operates while its traveling is stopped, or when the operation is halted, for example, and thus the gantry traveling device is secured to the rail by the gantry anchoring device. Here, the gantry anchoring device is provided separately from the gantry traveling device, and is coupled to the gantry traveling device through a connecting place. In addition, the seismic isolation system is provided between the crane body and the gantry traveling device, and the operation of the seismic isolation system is suppressed by the suppression unit under a normal condition.

{0019}
When the seismic force in the direction perpendicular to the extending direction of the rail is input, the coupling between the gantry traveling device and the gantry anchoring device through the connecting place is released. When the detection unit detects that the coupling through the connecting place is released, by which the detection unit detects the seismic force, the gantry anchoring device secured to the rail is released by the first release unit, such that the gantry traveling device secured to the rail is released. In addition, when the detection unit detects the seismic force, the second release unit releases the operation of the seismic isolation system suppressed by the suppression unit. As a result, when an earthquake occurs, the gantry traveling device can move along the rail, and a seismic isolation effect with respect to the seismic force in the direction parallel to the extending direction of the rail can be attained by the gantry traveling device and the rail, and a seismic isolation effect with respect to the seismic force in the direction perpendicular to the extending direction of the rail can also be attained by the seismic isolation system.

{0020}
In addition, when the coupling between the gantry traveling device and the gantry anchoring device through the connecting place is released in response to the input of the seismic force, the gantry traveling device moves along the rail, and may collide against the gantry anchoring device.

However, according to the present invention, since the first release unit releases the gantry anchoring device secured to the rail, even if the gantry traveling device moves along the rail and collides against the gantry anchoring device, the gantry anchoring device can also move at the same time, thereby reducing damage to the gantry traveling device.

{0021}
The gantry anchoring device described herein is a gantry anchoring device provided separately from the gantry traveling device (for example, a rail clamp, an apparatus for pushing against the top face of the rail, etc.). Alternatively, the gantry anchoring device may be an anchoring device for securing the crane body to the ground.

{Advantageous Effects of Invention}

{0022}

According to the present invention, when an earthquake occurs, it is possible to reliably attain a seismic isolation effect also with respect to seismic force in the direction parallel to the extending direction of the rail.

{Brief Description of Drawings}

{0023}

{Figure l} Figure 1 is a partially enlarged side view illustrating a container crane according to a first embodiment of the present invention.

{Figure 2} Figure 2 is a side view illustrating a seismic isolation system.

{Figure 3} Figure 3 is a cross sectional view illustrating a rail clamp.

{Figure 4} Figure 4 is a side view illustrating a rail brake.

{Figure 5} Figure 5 is a cross sectional view illustrating an anchoring device,

{Figure 6} Figure 6 shows a flow chart illustrating an operation of the container crane according to the first embodiment of the present invention.

{Figure 7} Figure 7 shows a flow chart illustrating an operation of the container crane according to a second embodiment of the present invention.

{Figure 8} Figure 8 shows a flow chart illustrating an operation of the container crane according to a third embodiment of the present invention.

{Description of Embodiments}

{0024}
Hereinafter, embodiments according to the present invention will be explained with reference to the drawings.

{First Embodiment}
A container crane according to the present embodiment is a bridge crane installed at a quay of a container terminal, is equipped with hoisting beams for handling containers and movably travels along a track (a rail). The container crane is secured to the rail or the ground by a gantry anchoring device so as to prevent the crane from traveling along the rail when the crane operates while its traveling is stopped, or when the operation is halted because of blast of wind or the like.

{0025}
In the present specification, a case where the present invention is applied to a container crane is explained, but application examples of the present invention are not limited to this. Any other crane may be used as far as the crane is provided with a seismic isolation system, a gantry traveling device thereof can travel on the rail, and the crane is secured to the rail or the ground by a gantry anchoring device at times other than when the crane travels. .

{0026}
Figure 1 is a partial side view illustrating an example of the container crane provided with a gantry anchoring device. Figure 1 illustrates a gantry traveling device 2 and a gantry anchoring device (a rail clamp 3, a rail brake 4, an anchoring device 5) of the container crane.

{0027}
The gantry traveling device 2 is provided in a lower portion of a crane body 1 of the container crane through a seismic isolation system 13. The gantry traveling device 2 travels along a rail 20 to move the crane body 1 along the rail 20. The gantry traveling device 2 includes trucks 6, an equalizing beam 7 and wheels 22. The truck 6 is provided with the wheels 22, and the plurality of trucks 6 are connected to one another through the equalizing beam 7. The upper face of the equalizing beam 7 is connected to the seismic isolation system 13.

{0028}
The rail clamp 3 is disposed on the rail 20 and is connected to the truck 6 of the gantry traveling device 2 through a connecting place 8. The rail clamp 3 can grip the rail 20, and as a result, the crane body 1 can be secured to the rail 20. Figure 3 illustrates one example of the rail clamp 3. The rail clamp 3 includes a clamp mechanism 14, and the clamp mechanism 14 grips or releases side faces of the rail 20 from the opposite sides. The rail clamp 3 performs a securing or releasing operation upon receipt of a control signal. For example, the clamp mechanism 14 of the rail clamp 3 is one example of a release unit or a first release unit, which releases the grip upon receipt of an earthquake detection signal.

{0029}
The connecting place 8 couples the tracks 6 of the gantry traveling device 2 and the rail clamp 3 . The rail* clamp 3 is provided with a shear pin, and when seismic force in the gantry traveling direction (the direction parallel to the rail-extending direction) input into the connecting place 8 is equal to or more than a predetermined value, the shear pin of the connecting place 8 is cut off. Note that the connecting place 8 is provided with a not-shown sensor (the detection unit) for detecting the cut-off of the shear pin.

{0030}
The rail brake 4 is connected to the lower portion of the crane body 1 and pushes against a top face of the rail 20. Since the rail brake 4 pushes against the rail 20, the crane body 1 can be secured to the rail 20. Figure 4 illustrates one example of the rail brake 4. The rail brake 4 includes a support frame 9 and a brake unit 10. The support frame 9 and the brake unit 10 are joined by pins 15, for example. An upper face of the support frame 9 is connected to the crane body 1, and a lower face of the support frame 9 is connected to the brake unit 10. The brake unit 10 pushes against or releases the rail 20. The rail brake 4 performs a securing or releasing operation upon receipt of a control signal. For example, the breaking section 10 of the rail brake 4 is one example of a release unit or a first release unit and performs the operation of releasing the pushing upon receipt of an earthquake detection signal.

{0031}

The anchoring device 5, as illustrated in Figure 1, is connected to a lower portion of the equalizing beam 7. The anchoring device 5 includes a support frame 11 and a stopper pin 12. An upper face of the support frame 11 is connected to the equalizing beam 7, and the stopper pin 12 is housed within the support frame 11. Figure 5 illustrates one example of the anchoring device 5. The stopper pin 12, as illustrated in Figure 5, is movable in a direction perpendicular, and is moved downward to be dropped into a ditch-like foundation metal fitting 21 provided in the ground, thereby enabling the crane body 1 to be secured to the ground. Upon receipt of a control signal, the stopper pin 12 moves in the direction perpendicular, for example, by use of a lever member 16. For example, the stopper pin 12 of the anchoring device 5 moves upward upon receipt of an earthquake detection signal.

{0032}
The seismic isolation system 13, as illustrated in Figure 1, is provided between the crane body 1 and the gantry traveling device 2, and reduces seismic force input into the crane body 1 in the direction perpendicular to the gantry traveling direction (the direction perpendicular to the extending direction of the rail 20). Figure 2 illustrates one example of the seismic isolation system. The seismic isolation system 13 includes swing bearings 17, 18, a spring member 19 and a damper member 23, etc. Pivots of the swing bearings 17, 18 are in a direction perpendicular to the ground level. The spring member 19 and the damper member 23 are provided such that longitudinal directions thereof are in the direction perpendicular to the extending direction of the rail 20. The seismic isolation system 13 is provided with a shear pin 24 (a suppression unit), and the shear pin 24 of the seismic isolation system 13 is cut off if seismic force in the direction perpendicular to the gantry traveling direction that is input into the seismic isolation system 13 is equal to or more than a predetermined value. Note that the seismic isolation system 13 is provided with a not-shown sensor (a detection unit) for detecting the cut-off of the shear pin 24 and a not-shown apparatus (a second release unit) for forcibly pulling off or cutting off the shear pin 24 . The seismic force of the predetermined value described herein at which the shear pin 24 is cut off is, for example, seismic force in Level II earthquake motions specified in 'Ministerial Ordinance for the Technical Standards for Port and Harbor Facilities (Ordinance of the Ministry of Land, Infrastructure, Transport and Tourism No. 15 of March 26, 2007)', or in 1 Public Notice Specifying Details of the Technical Standards for Port and Harbor Facilities (Public Notice of the Ministry of Land, Infrastructure, Transport and Tourism No. 3 95 of March 28, 2007) ' .

{0033}

Next, with reference to Figure 6, an operation when seismic force acts on the container crane of the present embodiment will be explained. Hereinafter, a case in which the gantry traveling device 2 is secured to the rail 20 or the ground while the container crane is in the crane-handling operation or the operation is halted will be explained.

{0034}
The container crane is on stand-by to detect an earthquake while the crane is secured so as not to move in the extending direction of the rail 20 (Step SI). In the earthquake detection stand-by state, if an earthquake occurs and seismic force in the direction perpendicular to the gantry traveling direction that is input into the seismic isolation system 13 is equal to or more than the predetermined value, the shear pin 24 of the seismic isolation system 13 is cut off. As a result, the seismic isolation system 13 starts actuation (Step S2) . In addition, the cut-off of the shear pin 24 of the seismic isolation system 13 is detected by the sensor, and then the gantry anchoring device is released (Step S3) .

{0035}
Here, the cut-off of the shear pin 24 in the seismic isolation system 13 is detected by the sensor installed in vicinity of the shear pin 24. The sensor for detecting the cut-off of the shear pin 24 is a proximity sensor, a lever sensor or the like that can detect a relative displacement of a member, for example.

{0036}
The gantry anchoring device includes the rail clamp 3 and the rail brake 4. When the cut-off of the shear pin 24 is detected, the rail clamp 3 releases the gripped rail 20 by-actuating a hydraulic mechanism. The rail brake 4 releases the push against the top face of the rail 20 when the cut-off of the shear pin 24 is detected. Note that the releasing of the rail brake 4 may be carried out by releasing the coupling through the pins 15 provided between the support frame 9 and the brake unit 10 of the rail brake 4. As described above, the container crane secured by the gantry anchoring device is released, so as to become movable along the rail 20.

{0037}
Accordingly, when an earthquake occurs, by the actuation of the seismic isolation system 13 the container crane can attain a seismic isolation effect with respect to the seismic force in the direction perpendicular to the extending direction of the rail 20, and the container crane can also attain a seismic isolation effect with respect to the seismic force in the direction parallel to the extending direction of the rail by sliding friction between the rail 20 and the wheels 22 of the gantry traveling device 20 or friction of the brake provided at the wheel drive unit.

{0038}
Conventionally, until a seismic load as strong as to cut off the shear pin of the connecting place 8 acts in the gantry-traveling direction of the crane, the gantry traveling device 2 is prevented from sliding in the gantry traveling direction by the rail clamp 3. In addition, in a prior art, when the shear pin of the connecting place 8 is cut off in response to the input of the seismic force and the coupling between the gantry traveling device 2 and the rail clamp 3 is released, even though the seismic isolation effect in the gantry traveling direction can be attained, the gantry traveling device 2 moves along the rail 20, and may collide against the rail clamp 3.

{0039}
However, according to the present embodiment, since the rail clamp 3 secured to the rail 20 is released, even if the gantry traveling device 2 moves along the rail 20 and collides against the rail clamp 3, the rail clamp 3 can also move along the rail 20 at the same time, thereby reducing damage to the gantry traveling device 2.

{0040}

{Second Embodiment}
In the first embodiment, the explanation has been provided on the case where the release of the gantry anchoring device is triggered by the actuation of the seismic isolation system 13 with respect to the seismic force in the direction perpendicular to the extending direction of the rail 20. In the second embodiment, the releasing of a gantry anchoring device is triggered by seismic force in the direction parallel to the extending direction of a rail 20. Figure 7 shows a flow chart illustrating an operation of a crane of the present embodiment.

{0041}
First, the container crane is on stand-by to detect an earthquake while the container crane is secured so as not to move in the extending direction of the rail 20 (Step Sll). In the earthquake detection stand-by state, if an earthquake occurs and seismic force in the gantry traveling direction that is input into a connecting place 8 between a gantry traveling device 2 and a rail clamp 3 is equal to or more than the predetermined value, a shear pin of the connecting place 8 is cut off (Step S12). As a result, the gantry traveling device 2 becomes movable along the rail 20, and the seismic isolation effect can be attained by sliding friction or the like between the rail 20 and wheels 22 of the gantry traveling device 2.

{0042}
Then, the cut-off of the shear pin of the connecting place 8 is detected by a sensor, by which a shear pin 24 of a seismic isolation system 13 is released (Step S13). As a result, even in a case where at the time of occurrence of an earthquake, the seismic force in the direction perpendicular to the gantry traveling direction that is input into the seismic isolation system 13 does not become equal to or more than the predetermined value and the shear pin 24 of the seismic isolation system 13 is not cut off, the release of the shear pin 24 of the seismic isolation system 13 is triggered by the cut-off of the shear pin of the connecting place 8, thereby enabling the seismic isolation system 13 to start actuation.

{0043}
Here, the cut-off of the shear pin of the connecting place 8 is detected by a sensor installed in vicinity of the shear pin, as similar to the case of the shear pin 24 of the seismic isolation system in the first embodiment. In addition, the release of the shear pin 24 of the seismic isolation system 13 is carried out by providing the seismic isolation system 13 with a mechanism for forcibly pulling off or cutting off the shear pin 24, and actuating this mechanism.

{0044}
When the cut-off of the shear pin of the connecting place 8 is detected by the sensor, a gantry anchoring device is released (Step S14). As similar to the first embodiment, the gantry anchoring device includes the rail clamp 3 and a rail brake 4.

{0045}
Therefore, when an earthquake occurs, with respect to the seismic force in the direction parallel to the extending direction of the rail 20, the coupling of the connecting place 8 is released and the gantry traveling device 2 becomes movable, enabling the container crane to attain the seismic isolation effect by sliding friction or the like between the rail 20 and the wheels 22 of the gantry traveling device 2. In addition, the shear pin 24 of the seismic isolation system 13 is forcibly released so as to actuate the seismic isolation system 13, by which the container crane can attain the seismic isolation effect with respect to the seismic force in the direction perpendicular to the extending direction of the rail 20, as well.

{0046}
When the coupling between the gantry traveling device 2 s and the rail clamp 3 is released by the cut-off of the shear pin of the connecting place 8 in response to the input of the seismic force, although the seismic isolation effect in the gantry traveling direction can be attained, the gantry traveling device 2 travels along the rail 20, and may collide against the rail clamp 3. However, according to the present embodiment, since the rail clamp 3 secured to the rail 2 0 is released, even if the gantry traveling device 2 moves along the rail 20 and collides against the rail clamp 3, the rail clamp 3 can also move along the rail 20 at the same time, thereby reducing damage to the gantry traveling device 2.

{0047}

{Third Embodiment}
In the above-described first embodiment and second embodiment, the explanations have been provided on the cases where the rail clamp 3 and the rail brake 4 of the gantry anchoring device are released, but the present invention is not limited to these examples. For example, an anchoring device 5 may be released when an earthquake occurs. Figure 8 shows a flow chart illustrating an operation of a crane according to the present embodiment.

{0048}
First, the container crane is on stand-by to detect an earthquake while the crane is secured so as not to move along a rail 20 (Step S21). In the earthquake detection stand-by state, if an earthquake occurs and seismic force in the direction perpendicular to the gantry traveling direction that is input into a seismic isolation system 13 is equal to or more than the predetermined value, a shear pin 24 of the seismic isolation system 13 is cut off. As a result, the seismic isolation system 13 starts actuation. Alternatively, in the earthquake detection stand-by state, if an earthquake occurs and seismic force in the gantry traveling direction that is input into a connecting place 8 between a gantry traveling device 2 and a rail clamp 3 is equal to or more than the predetermined value, a shear pin of the connecting place 8 is cut off (Step S22).

{0049}
When the cut-off of the shear pin 24 of the seismic isolation system 13 or the cut-off of the shear pin of the connecting place 8 is detected by a sensor, the anchoring device 5 is released (Step S23). As a result, the gantry traveling device 2 becomes movable along the rail 20, and the seismic isolation effect can be attained by sliding friction or the like between the rail 20 and wheels 22 of the gantry traveling device 2. Accordingly, in a case where the crane is secured to the ground by the anchoring device 5 in addition to the rail clamp 3 and a rail brake 4, the crane becomes movable in the extending direction of the rail 20 when an earthquake occurs.

{0050}
Note that the gantry anchoring device is not limited to the rail clamp 3, the rail brake 4 and the anchoring device 5 that are separately provided from the gantry traveling device 2. For example, the gantry anchoring device may be a mechanical brake or an electric motor brake with respect to the wheels 22 provided with the gantry traveling device 2, and these gantry anchoring devices may be released when the cutoff of the shear pin 24 of the seismic isolation system 13 or the cut-off of the shear pin of the connecting place 8 is detected by the sensor.

{0051}
As described above, according to the present embodiment, since the gantry anchoring device is released due to an occurrence of an earthquake, vibrations can be absorbed and alleviated by sliding friction or the like between the wheels 22 of the gantry traveling device 2 of the container crane and the rail 20, thereby producing the seismic isolation effect in the gantry traveling direction. In addition, the seismic isolation effect in the direction perpendicular to the travelling direction can also be attained by the seismic isolation system 13. Conventionally, since the seismic isolation effect in the direction perpendicular to the travelling direction can be attained but the seismic isolation effect in the gantry traveling direction cannot be attained sufficiently, if seismic force is input in the gantry traveling direction or in an oblique direction, torsion is caused to the crane body 1, and the crane body 1 becomes deformed toward the direction perpendicular to the gantry traveling direction. Consequently, a slide stroke is applied to the seismic isolation system 13 for attaining the seismic isolation effect in the direction perpendicular to the gantry traveling direction, which may cause such a problem that the seismic isolation system 13 itself cannot be effective or the wheels 22 float up in spite of making use of the capability at a maximum level. To the contrary, according to the present embodiment, it is possible to substantially counter an earthquake in any direction, and thereby the above-mentioned problem can be prevented.

{0052}
In addition, according to the present embodiment, in order to counter an earthquake in any direction, it is not necessary to provide a special apparatus similar to the seismic isolation system 13, but it is only necessary to provide an apparatus for detecting the release of the shear pin 24 of the seismic isolation system 13 or the release of the shear pin of the connecting place 8 and an apparatus for forcibly releasing the shear pin 24, as well as to modify control logics of the rail clamp 3, the rail brake 4 and/or the anchoring device 5, which results in low cost. In addition, even in a case of improving an existing crane, a large-scale improvement is unnecessary, and the improvement can be achieved in a short term with low cost.

{0053}
In the above-described embodiment, the case of using the shear pin 24 of the seismic isolation system 13 or the shear pin of the connecting place 8 for the sake of detecting an earthquake has been explained, but other embodiments can be considered. For example, a vibration detection using a seismometer or a plumb bob may be employed so as to release the gantry anchoring device such as the rail clamp 3 or the like. However, in some cases, such detection that uses a seismometer or a plumb bob may cause misdetection due to vibrations other than an earthquake, and thus the gantry anchoring device may be released unexpectedly because of such misdetection, which results in a problem. Furthermore, it is required to use an apparatus such as a seismometer and a plumb bob in addition to the seismic isolation system, which requires additional cost and makes the configuration uneconomical. Note that the shear pin 24 of the seismic isolation system 13 or the shear pin of-the connecting place 8 is never cut off by a wind or the like during a normal operation. Therefore, the detection of an earthquake by use of the shear pin 24 of the seismic isolation system 13 or the shear pin of the connecting place 8 can prevent the gantry anchoring device from being released due to misdetection.

{0054}
In the normal operation of the container crane, when the container crane comes into the traveling stop state from the traveling state, the gantry anchoring device automatically operates to secure the container crane to the rail or the ground. In order to realize the present embodiment, if an earthquake occurs during the traveling of the container crane and the traveling is stopped, it is preferable to prevent the gantry anchoring device from operating, or to release the gantry anchoring device by an earthquake detection even if the gantry anchoring device operates.

{Reference Signs List}

{0055}
1 Crane body
2 Gantry traveling device
3 Rail clamp (gantry anchoring device)
4 Rail brake (gantry anchoring device)
5 Anchoring device (gantry anchoring device)
6 Truck
7 Equalizing beam
8 Connecting place
9, 11 Support frames
12 Stopper pin
13 Seismic isolation system
14 Clamp mechanism
15 Pin
16 Lever member
17, 18 Swing bearings
19 Spring member
20 Rail
21 Foundation metal fitting
22 Wheel

23 Damper member
24 Shear pin (suppression unit)

{I/WE CLAIM}

{Claim 1}

A crane comprising

a crane body;

a gantry traveling device that travels along a rail to move the crane body;

a gantry anchoring device for securing the gantry traveling device to the rail so as to prevent the gantry traveling device from traveling along the rail;

a detection unit for detecting seismic force,- and

a release unit for releasing the gantry traveling device secured to the rail by the gantry anchoring device when the detection unit detects the seismic force.

{Claim 2}
The crane according to claim 1, further comprising a seismic isolation system provided between the crane body and the gantry traveling device so as to reduce seismic force input into the crane body in a direction perpendicular to an extending direction of the rail, wherein the seismic isolation system starts to operate when the detection unit detects the seismic force.

{Claim 3}
The crane according to claim 2, further comprising a suppression unit for suppressing an operation of the seismic isolation system under a normal condition, and releasing the suppressed operation of the seismic isolation system in response to the input of the seismic force in the direction perpendicular to the extending direction of the rail, wherein

the detection unit detects the seismic force by detecting that the operation of the seismic isolation system suppressed by the suppression unit is released.

{Claim 4}

A crane comprising

a crane body;

a gantry traveling device that travels along a rail to move the crane body;

a seismic isolation system provided between the crane body and the gantry traveling device;

a gantry anchoring device provided separately from the gantry traveling device and secured to the rail in order to secure the crane body so as to prevent the crane body from traveling along the rail;

a connecting place for coupling the gantry traveling device and the gantry anchoring device under a normal condition, and releasing the coupling between the gantry traveling device and the gantry anchoring device in response to an input of seismic force in a direction parallel to an extending direction of the rail;

a suppression unit for suppressing an operation of the seismic isolation system in the normal state;

a detection unit for detecting the seismic force by detecting that the coupling between the gantry traveling device and the gantry anchoring device through the connecting place is released;

a first release unit for releasing the gantry anchoring device secured to the rail when the detection unit detects the seismic force; and

a second release unit for releasing the operation of the seismic isolation system suppressed by the suppression unit when the detection unit detects the seismic force.