JP2021147167A - Crane and control method for the same - Google Patents

Abstract

To provide a crane and a control method for the same that are able to miniaturize the driving mechanism of a trolley while suppressing an increase in an amount of energy required for loading.SOLUTION: When a container C is loaded by a suspender 6 suspended from a trolley 5 by traversing the trolley 5 along a main girder 3 supported by a leg structure 2 and extending in an ocean land direction x, the main girder 3 is tilted and fixed by a tilting mechanism 7 to a state of tiling downward from an ocean side to a land side, then, an import operation for taking the container C out of a vessel 11 is performed. After the main girder 3 is tilted and fixed to a state of tilting downward from the land side to the ocean side, an export operation for loading the container C into the vessel 11 is performed.SELECTED DRAWING: Figure 1

Description

The present invention relates to a crane provided with a trolley traversing along a main girder and a control method thereof, and is capable of realizing a miniaturization of a trolley drive mechanism while suppressing an increase in the amount of energy required for cargo handling. It relates to a control method.

Various cranes having a trolley traversing along the main girder have been proposed (see, for example, Patent Document 1). The crane described in Patent Document 1 includes a tilting mechanism for tilting the main girder. The tilting mechanism was equipped with a configuration in which the main girder was constantly tilted so that the trolley was always tilted downward. Since the trolley moves only on the downward slope, the drive mechanism of the trolley can be miniaturized.

Every time the direction of the trolley changed, the relatively heavy main girder was tilted. In other words, the number of containers to be handled and the number of times the main girder was tilted by the tilting mechanism were in agreement. A huge amount of energy was required to tilt the main girder by the tilting mechanism. The crane described in Patent Document 1 has a problem that the amount of energy required for the cargo handling work as a whole increases.

In addition, since it was necessary to tilt the main girder according to the traversing speed of the trolley, the tilting mechanism had to be composed of a large device with a relatively large output. For example, if the trolley traversed from the sea side to the land side in 5 seconds, the tilting mechanism had to change the relatively heavy main girder from downhill to horizontal or uphill in 5 seconds. There was a problem that the tilting mechanism became large. In addition, there is a problem that the manufacturing cost when manufacturing the crane increases.

Japanese Patent Application Laid-Open No. 63-012587

The present invention has been made in view of the above problems, and an object of the present invention is to provide a crane and a control method thereof capable of realizing miniaturization of a trolley drive mechanism while suppressing an increase in the amount of energy required for cargo handling. Is.

Cranes for achieving the above objectives are suspended from the leg structure, the main girder supported by the leg structure and extended in the land and sea direction, the trolley traversing along the main girder, and this trolley. A crane including a hanging tool that is suspended so that a load can be gripped, and a tilting mechanism that tilts the main girder so that the sea-side end moves in the vertical direction with respect to the land-side end of the main girder. In the above, the main girder is provided with a control mechanism for controlling the tilting mechanism, and when the control mechanism performs import work for taking out cargo from a ship, the main girder is tilted downward from the sea side to the land side. When carrying out export work in which cargo is loaded onto a ship by fixing it, the main girder is characterized in that the main girder is fixed so as to have a downward slope from the land side to the sea side.

The control method of the crane for achieving the above object is to make the trolley traverse along the main girder supported by the leg structure and extend in the land-sea direction, and to suspend the trolley. In the control method of a crane that handles cargo, the main girder is tilted and fixed so that it tilts downward from the sea side to the land side, and then the cargo is taken out from the ship and imported from the land side to the sea. It is characterized in that the main girder is tilted and fixed so as to be inclined downward toward the side, and then the export work of loading the cargo onto the ship is performed.

According to the present invention, the main girder is fixed during the import work or the export work. It is advantageous to suppress an increase in the amount of energy required for cargo handling. In addition, the trolley can accelerate with a relatively small force because the direction of travel is downward when the cargo is being held. It is advantageous for downsizing the drive mechanism of the trolley.

It is explanatory drawing which illustrates the state of the import work of a crane. It is explanatory drawing which illustrates the state of the export work of the crane of FIG. It is explanatory drawing which illustrates the modification of the crane of FIG. It is explanatory drawing which expands and exemplifies the tilting mechanism of FIG. It is explanatory drawing which schematically exemplifies the state of the import work and the export work of the crane of FIG. It is explanatory drawing which illustrates the modification of the crane of FIG. It is explanatory drawing which illustrates the AA arrow view of FIG. It is explanatory drawing which schematically exemplifies the state of the import work and the export work of the crane of FIG.

Hereinafter, the crane and the control method will be described based on the embodiment shown in the figure. In the figure, the traveling direction of the crane is indicated by an arrow y, the transverse direction crossing the traveling direction at a right angle is indicated by an arrow x, and the vertical direction is indicated by an arrow z.

As illustrated in FIG. 1, the crane 1 includes a leg structure 2, a main girder 3 supported by the leg structure 2 and extended in the land-sea direction, and a traveling device installed below the leg structure 2. It is equipped with 4. The crane 1 is composed of, for example, a quay crane.

The leg structure 2 includes a plurality of leg members 2a extending in the vertical direction z, a plurality of horizontal members 2b connecting the leg members 2a, and an A frame extending upward from the sea-side leg member 2a. It is composed of 2c and the like. The horizontal member 2b may be extended in the transverse direction x or may be extended in the traveling direction y.

In this embodiment, the main girder 3 has a girder 3a supported by the leg structure 2 and a boom 3b extending from the sea side end portion of the girder 3a toward the sea side. The land-sea direction in which the main girder 3 is extended is a direction parallel to the transverse direction x that crosses the traveling direction y of the crane 1 at a right angle.

The crane 1 includes a trolley 5 traversing along the main girder 3 in the transverse direction x, and a suspending tool 6 suspended from the trolley 5. The trolley 5 traverses by, for example, a drive mechanism composed of a motor. The configuration of the drive mechanism is not limited to the motor, and any mechanism may be used as long as it can add power for the trolley 5 to traverse the trolley 5. The drive mechanism may be composed of, for example, a drum installed on the crane 1 and a wire drawn out from the drum and connected to the trolley 5. This drive mechanism can traverse the trolley 5 by winding or unwinding the wire.

In this embodiment, the hanger 6 is composed of a spreader that can grip the container C, which is a load. The hanger 6 is suspended from the trolley 5 by a wire.

The crane 1 includes a tilting mechanism 7 arranged between the leg structure 2 and the traveling device 4. In this embodiment, the tilting mechanism 7 is composed of jacks that can be expanded and contracted in the vertical direction z. The jacks are arranged on the upper parts of the traveling devices 4 arranged at the four corners of the crane 1 in a plan view. For example, if the jack on the sea side is extended longer than the jack on the land side, the main girder 3 can be tilted so that the land side end is downward with respect to the sea side end of the main girder 3. That is, the main girder 3 tilts with the traveling direction y as the central axis. If the jack on the land side of the jack on the sea side is extended longer, the main girder 3 can be tilted so that the end on the sea side is downward with respect to the end on the land side of the main girder 3.

In this embodiment, the tilting mechanism 7 is arranged on the upper part of the traveling device 4. Therefore, the leg members 2a, the horizontal members 2b, the A frame 2c, and the like constituting the leg structure 2 are also tilted by the tilting mechanism 7 together with the main girder 3. In FIG. 1, the inclination of the main girder 3 with respect to the horizontal direction x, which is the horizontal direction, is indicated by θ. The tilting mechanism 7 may be arranged in the vicinity of the seismic isolation device arranged on the upper part of the traveling device 4, for example. Further, the tilting mechanism 7 may be arranged in the middle of the leg member 2a.

The configuration of the tilting mechanism 7 is not limited to the above. The tilting mechanism 7 may have a configuration in which the sea-side end of the main girder 3 is moved in the vertical direction z with respect to the land-side end.

The crane 1 includes a control mechanism 8 that controls the tilting mechanism 7. The control mechanism 8 is installed in, for example, the cab 9 of the crane 1. In FIG. 1, the control mechanism 8 is shown by a broken line for explanation. The place where the control mechanism 8 is installed is not limited to the above, and may be installed in another place such as the machine room 10 of the crane 1. The control mechanism 8 can be installed on the crane 1 itself or in the vicinity of the crane 1.

As illustrated in FIG. 1, when importing cargo such as container C, the main girder 3 of the crane 1 is first tilted by the tilting mechanism 7 so as to be tilted downward toward the land side, and then fixed. .. The land side end of the main girder 3 is lower than the sea side end in the vertical direction z. The import work is the work of taking out the container C, which is a baggage, from the ship 11 and unloading it to the container terminal on the land side.

The trolley 5 grips the container C of the ship 11 with the hanger 6 and then traverses toward the land side. In FIG. 1, for the sake of explanation, the traversing direction of the trolley 5 holding the luggage is indicated by a white arrow. The trolley 5 holding the luggage traverses the downward slope. After lowering the container C on the land side, the empty trolley 5 traverses toward the sea side. The trolley 5 that does not hold the luggage traverses the uphill slope.

By repeating the above, the crane 1 moves the container C of the ship 11 to the land side. The import work is completed when the unloading of container C is completed.

When exporting luggage as illustrated in FIG. 2, the main girder 3 of the crane 1 is first tilted by the tilting mechanism 7 so as to be tilted downward toward the sea side, and then fixed. The sea side end of the main girder 3 is lower than the land side end in the vertical direction z. The export work means the work of loading the container C, which is a load, from the container terminal on the land side to the ship 11.

The tilting of the main girder 3 by the tilting mechanism 7 is executed by operating the control mechanism 8 based on, for example, a button operation by the driver of the crane 1. When the import work and the export work are switched, the tilt of the main girder 3 is controlled by the control mechanism 8.

The trolley 5 grips the container C on the land side with the hanger 6 and then traverses toward the sea side. In FIG. 2, for the sake of explanation, the traversing direction of the trolley 5 holding the luggage is indicated by a white arrow. The trolley 5 holding the luggage traverses the downward slope. After the container C is unloaded on the ship 11, the empty trolley 5 traverses toward the land side. The trolley 5 that does not hold the luggage traverses the uphill slope.

By repeating the above, the crane 1 loads the container C on the ship 11. The export work is completed when the loading of the container C is completed.

The trolley 5 holding the container C, which is a load, traverses a downward slope in both the import work and the export work. The trolley 5 can obtain a force in the traveling direction by utilizing the weight of the container C. This force allows the trolley 5 to increase its acceleration. It is possible to miniaturize the drive mechanism of the trolley 5 without reducing the acceleration of the trolley 5.

The empty trolley 5 traverses an uphill slope. Since the trolley 5 does not grip the container C, it is possible to suppress a force that is opposite to the traveling direction as compared with the case where the container C is gripped. The trolley 5 can suppress a decrease in acceleration in the traveling direction. Even with a relatively small drive mechanism, the trolley 5 can climb an uphill slope.

It is advantageous to miniaturize the drive mechanism while maintaining the acceleration of the trolley 5 at a predetermined value. The capacity of the motor for running the trolley 5 and the motor of the drum used when towing the trolley 5 with a wire can be reduced. Further, it is advantageous to increase the acceleration of the trolley 5 while maintaining the size of the drive mechanism. The cargo handling speed of the crane 1 can be improved.

The main girder 3 is fixed in a state where it is inclined downward to the land side when importing work is performed, and in a state where it is inclined downward to the sea side when carrying out export work. The tilting mechanism 7 tilts the main girder 3 only when the import operation and the export operation are switched. During the import work or export work, the inclination of the main girder 3 is fixed.

For example, the import work and the export work of the crane 1 are usually switched once for one ship 11. In this case, the tilting mechanism 7 tilts the main girder 3 once for one ship 11. It is advantageous to suppress an increase in the amount of energy required for cargo handling.

The number of tilts of the main girder 3 is extremely small. When the tilting mechanism 7 tilts the main girder 3, the number of tilts is small even if it takes some time, so that the effect on the overall cargo handling efficiency is small. Therefore, the equipment constituting the tilting mechanism 7 can be miniaturized.

The tilting mechanism 7 may be prohibited from tilting the main girder 3 while the trolley 5 is traversing. It is possible to prevent the acceleration of the trolley 5 during traversing from changing with the change in the inclination of the main girder 3. It is possible to prevent the acceleration of the trolley 5 from fluctuating due to the influence of the inclination of the main girder 3 and the container C gripped by the hanger 6 from swinging.

Crane 1 is not limited to quay cranes. The crane 1 may be composed of a low profile crane. The low profile crane includes a sliding boom supported by the leg structure 2 and slidable in the transverse direction x.

The low profile crane has jacks arranged on the leg structure 2 at intervals in the transverse direction x. The sliding boom may have a configuration that is supported and fixed by this jack. In this case, for example, by extending the jack on the sea side from the land side, a downward slope from the sea side to the land side can be formed. That is, the jack conventionally provided in the low profile crane can be used as the tilting mechanism 7. The control mechanism 8 can control the inclination θ of the sliding boom, which is the main girder 3, by controlling the expansion and contraction of the jack between the sea side and the land side.

The crane 1 may be composed of an unloader that handles loose cargo such as coal as cargo. At this time, the hanger 6 is composed of a grab bucket for handling loose loads.

As illustrated in FIG. 3, the tilting mechanism 7 may tilt only the boom 3b. The boom 3b tilts around the connecting portion between the sea side end of the girder 3a and the land side end of the boom 3b. In this embodiment, the tilt mechanism 7 is installed on the forestay 12 that connects the A frame 2c and the boom 3b and supports the load of the boom 3b. FIG. 3 shows the state of the crane 1 at the time of import work. The boom 3b is fixed in a state of being inclined downward to the land side. The girder 3a maintains a horizontal state parallel to the transverse direction x.

As illustrated in FIG. 4, the tilting mechanism 7 is composed of an adjusting mechanism that changes the apparent length of the forestay 12. The adjusting mechanism is composed of, for example, a link connecting the forestay 12 and the boom 3b. The upper part of FIG. 4 shows a state in which the boom 3b is horizontal.

When tilting the boom 3b, first, the seaside end of the boom 3b is raised by a predetermined amount by an undulating rope that controls the undulation of the boom 3b. After that, as shown in the lower part of FIG. 4, the link constituting the adjustment mechanism is rotated about the traveling direction y as the central axis. The link is then constrained to rotate by a fixture (not shown). The adjustment mechanism shortens the apparent length of the forestay 12. Since the link is constrained to rotate, the load of the boom 3b is supported by the forestay 12.

The configuration of the adjustment mechanism installed on the boom 3b is not limited to the above. It suffices to have a structure that changes the apparent length of the forestay 12. The adjusting mechanism may be composed of a crank or a ball screw. Further, regardless of the lower end of the forestay 12, the adjustment mechanism may be installed at the upper end or an intermediate portion.

The configuration of the tilting mechanism 7 installed on the crane 1 is not limited to the above. The tilting mechanism 7 may be configured with another structure as long as it has a configuration for moving the sea-side end of the boom 3b in the vertical direction z with respect to the land-side end.

When the import work is carried out as illustrated in the upper part of FIG. 5, the trolley 5 grips the container C on the sea side and traverses toward the land side. The boom 3b is fixed so as to be inclined downward to the land side.

Generally, the traversal of the trolley 5 reaches the maximum speed after accelerating for a predetermined time. Start decelerating after reaching the maximum speed. In this embodiment, the trolley 5 accelerates by utilizing the downward inclination of the boom 3b, so that the trolley 5 can be efficiently accelerated toward the maximum speed. Since the trolley 5 decelerates at the horizontal girder 3a portion, it can be decelerated more efficiently than when decelerating on a downward slope.

The empty trolley 5 accelerates at the horizontal girder 3a. It can accelerate more efficiently than when accelerating on an uphill slope. The boom 3b, which has an uphill slope, is reached with the speed increased. Since the trolley 5 decelerates at the portion of the boom 3b that is inclined uphill, it can be decelerated efficiently.

From the above, in the import work in this embodiment, acceleration / deceleration of the trolley 5 can be performed more efficiently than in the embodiment illustrated in FIG. It is desirable to adopt the crane 1 that tilts only the boom 3b in the container terminal where the import work is more than the export work and the container terminal where the export work of empty containers is more. Since the unloader installed in a steel mill or the like is only for import work, it is advantageous to adopt a configuration in which only the boom 3b is tilted.

When exporting, the seaside end of the boom 3b is first lowered by a predetermined amount with an undulating rope. After that, the apparent length of the forestay 12 is increased by the adjusting mechanism. As illustrated below in FIG. 5, the boom 3b is fixed in a state of being inclined downward to the sea side.

The trolley 5 grips the container C on the land side and traverses toward the sea side. Since the trolley 5 traverses the boom 3b that is inclined downward, the acceleration of the trolley 5 increases due to the weight of the container C. The empty trolley 5 accelerates at the uphill boom 3b and decelerates at the horizontal girder 3a.

When exporting work, the boom 3b may be fixed in a horizontal state. Depending on the weight of the exported container C, the trolley 5 may be accelerated or decelerated more efficiently if the boom 3b is fixed in a horizontal state rather than in a downwardly inclined state.

The tilting mechanism 7 is composed of an adjusting mechanism that changes the apparent length of the forestay 12. Compared to the jack illustrated in FIG. 1, the load to be supported is significantly smaller, which is advantageous for suppressing the manufacturing cost of the tilting mechanism 7.

Only the boom 3b is tilted by the tilting mechanism 7. Compared to the leg structure 2 illustrated in FIG. 1, the weight of the member to be tilted is significantly smaller, which is advantageous for suppressing the amount of energy required by the tilting mechanism 7.

As illustrated in FIG. 6, the tilting mechanism 7 may tilt only the girder 3a. In this embodiment, the tilting mechanism 7 is installed on the back stay 13 that connects the A frame 2c and the girder 3a and supports the load of the girder 3a. FIG. 6 shows the state of the crane 1 at the time of import work. The girder 3a is fixed on the land side in a downward slope. The boom 3b maintains a horizontal state parallel to the transverse direction x.

The tilting mechanism 7 installed on the girder 3a is composed of an adjusting mechanism that changes the apparent length of the backstay 13. This adjusting mechanism can be configured by, for example, a link connecting the back stay 13 and the girder 3a, as in the embodiment illustrated in FIG.

The adjusting mechanism may be configured to include, for example, a motor that rotates the link about the traveling direction y as a central axis. The apparent length of the back stay 13 can be changed by rotating the link. After changing the apparent length of the back stay 13 by rotation, the link is in a state of being restrained from its rotation. The load of the girder 3a is supported by the back stay 13.

As illustrated in FIG. 7, the tilting mechanism 7 may be configured by a jack installed between a horizontal member 2b connecting a pair of land-side leg members 2a and a girder 3a and expanding and contracting in the vertical direction z. .. The expansion and contraction of the jack causes the girder 3a to tilt.

The configuration of the tilting mechanism 7 installed on the crane 1 is not limited to the above. The tilting mechanism 7 may be configured by another structure as long as it has a configuration in which the land side end portion of the girder 3a is moved in the vertical direction z with respect to the sea side end portion.

When importing, the tilting mechanism 7 lowers the land side end of the girder 3a by a predetermined amount. As illustrated above in FIG. 8, the girder 3a is fixed in a state of being inclined downward to the land side.

The trolley 5 grips the container C on the sea side and traverses toward the land side. Since the trolley 5 traverses the girder 3a which is inclined downward, the acceleration of the trolley 5 increases due to the weight of the container C. The empty trolley 5 accelerates at the uphill girder 3a portion and decelerates at the horizontal boom 3b portion.

When importing work, the girder 3a may be fixed in a horizontal state. Depending on the weight of the exported container C, the trolley 5 may be accelerated or decelerated more efficiently if the girder 3a is fixed in a horizontal state rather than in a downwardly inclined state.

When exporting, the tilting mechanism 7 raises the land side end of the girder 3a by a predetermined amount. As illustrated below in FIG. 8, the girder 3a is fixed in a state of being inclined downward to the sea side. The trolley 5 holding the container C on the land side accelerates by utilizing the downward inclination of the girder 3a. The trolley 5 can be efficiently accelerated by utilizing the weight of the container C. Since the trolley 5 decelerates at the horizontal boom 3b, it can be decelerated more efficiently than when decelerating on a downward slope.

The empty trolley 5 accelerates at the horizontal boom 3b. It can accelerate more efficiently than when accelerating on an uphill slope. It reaches the girder 3a, which has an uphill slope with the speed increased. Since the trolley 5 decelerates at the portion of the girder 3a that is inclined uphill, it can be decelerated efficiently.

From the above, in the export work in this embodiment, the acceleration / deceleration of the trolley 5 can be performed more efficiently than in the embodiment illustrated in FIG. In a container terminal that has more export work than import work and a container terminal that has more empty container import work, it is desirable to adopt the crane 1 that tilts only the girder 3a. Since the crane for shipping products installed in steelworks and the like is only for export work, it is advantageous to adopt a configuration in which only the girder 3a is tilted.

When the main girder 3 is composed of the girder 3a and the boom 3b, the tilting mechanism 7 may tilt both the girder 3a and the boom 3b so that they have the same inclination θ. The same effect as that of the embodiment illustrated in FIG. 1 can be obtained.

The maximum angle θmax of the inclination of the main girder 3 with respect to the horizontal direction may be preset. The control mechanism 8 can be configured to control the inclination θ of the main girder 3 within a range not exceeding the maximum angle θmax. The method of setting the maximum angle θmax will be described below. The export operation illustrated in FIG. 2 will be described as an example.

The force (force toward the sea) Fs required when the trolley 5 gripping the container C traverses to the sea side at the maximum acceleration Acc can be expressed by the following equation (2).

Here, Mt is the weight of the trolley 5 [ton], Mcon is the weight of the container C which is luggage [ton], Acc is the preset maximum acceleration of the trolley 5 [m / sec ² ], and g is the gravitational acceleration [m]. / Sec ² ] and θ indicate the inclination [deg] of the main girder 3 with respect to the horizontal direction x. The maximum acceleration Acc of the trolley 5 is preset at the time of manufacturing the crane 1 according to the cargo handling capacity required for the crane 1.

The force (force to land) Fl required when the empty trolley 5 traverses to the land side at the maximum acceleration Acc can be expressed by the following equation (3).

When the main girder 3 is horizontal, that is, when θ = 0 °, the force Fps required when the trolley 5 holding the container C traverses to the sea side at the maximum acceleration Acc is given by the following equation (4). Can be represented.

From the above equations (2) and (4), it can be seen that the force required for the trolley 5 holding the container C to traverse is smaller when the main girder 3 is tilted. The ratio of the force that can be reduced by the inclination θ of the main girder 3 can be expressed by the following equation (5).

On the other hand, when the empty trolley 5 traverses the land side, it traverses an uphill slope. If the land-bound force Fl required at that time is equal to or greater than the sea-bound force Fs, the trolley 5 cannot traverse to the land side with the drive mechanism miniaturized according to the sea-bound force Fs. That is, there is a limit to the magnitude of the slope θ. The following equation (6) was set as the condition of the slope θ.

主桁３の傾きθの最大値をθｍａｘとすると式（７）から以下の式（１）を求めることができる。

Assuming that the maximum value of the slope θ of the main girder 3 is θmax, the following equation (1) can be obtained from the equation (7).

For example, if the weight of the trolley 5 is Mt = 50 [ton], the weight of the container C is Mcon = 60 [ton], and the maximum acceleration of the trolley 5 is Acc = 1 [m / sec ² ], the maximum angle θmax = 2.19 [°]. It becomes. The control mechanism 8 controls the tilt mechanism 7 within a range in which the tilt θ of the main girder 3 is equal to or less than the maximum angle θmax. This maximum angle θmax is affected by the maximum acceleration Acc required for the trolley 5, the weight Mt of the trolley 5, and the magnitude of the weight Mcon of the cargo. The maximum angle θmax can also be set in advance when the capacity of the crane 1 and the weight of the target cargo are determined.

Under the same conditions as above, if the slope θ = 1 [°], the ratio of the force that can be reduced based on the equation (5) is 0.17, and if the slope θ = 2 [°], the ratio of the force that can be reduced is 0. It becomes 34. That is, the crane 1 can reduce the motor capacity of the trolley 5 by 17% or 34% while maintaining the maximum acceleration Acc of the trolley 5 at, for example, 1 [m / sec ^2].

1 Crane 2 Leg structure 2a Leg member 2b Horizontal member 2c A frame 3 Main girder 3a Girder 3b Boom 4 Traveling device 5 Trolley 6 Suspension 7 Tilt mechanism 8 Control mechanism 9 Driver's cab 10 Machine room 11 Ship 12 Forest stay 13 Back stay x Traverse direction (land and sea direction)
y Traveling direction z Vertical direction C Container Mt Weight of trolley Mcon Weight of luggage Acc Maximum acceleration of trolley g Gravity acceleration Fs Force to sea Fl Force to land Fl

Claims (8)

A leg structure, a main girder supported by this leg structure and extended in the land-sea direction, a trolley traversing along the main girder, and a trolley suspended from this trolley so that luggage can be gripped. In a crane provided with a hanger and a tilting mechanism that tilts the main girder so that the sea-side end moves in the vertical direction with respect to the land-side end of the main girder.
A control mechanism for controlling the tilting mechanism is provided.
When the control mechanism fixes the main girder in a state where the main girder is inclined downward from the sea side to the land side when carrying out the import work of taking out the cargo from the ship, and when carrying out the export work of loading the cargo on the ship. Is a crane characterized by having a configuration in which the main girder is fixed in a state where the main girder is inclined downward from the land side to the sea side. The crane according to claim 1, wherein the control mechanism includes a configuration in which the main girder is tilted by the tilting mechanism only when the export work and the import work are switched. The crane according to claim 1 or 2, wherein the control mechanism is provided with a configuration in which tilting of the main girder by the tilting mechanism is prohibited during traversing of the trolley. The main girder has a girder supported by the leg structure and a boom extending from the sea side end of the girder toward the sea side.
The crane according to any one of claims 1 to 3, wherein the tilting mechanism tilts only one of the girder and the boom. The maximum angle of inclination of the main girder with respect to the horizontal direction is preset in the control mechanism.
The crane according to any one of claims 1 to 4, wherein the maximum angle is determined by the following formula (1).

(In the formula (1), θmax is the maximum angle of inclination of the main girder with respect to the horizontal direction, Mcon is the weight of the luggage, Acc is the preset maximum acceleration of the trolley, Mt is the weight of the trolley, and g is. Gravitational acceleration). In a method for controlling a crane in which a trolley is traversed along a main girder supported by a leg structure and extended in the land-sea direction, and cargo is handled by a hanging tool suspended from the trolley.
After tilting and fixing the main girder so that it slopes downward from the sea side to the land side, import work is carried out to take out the luggage from the ship.
A control method characterized in that the main girder is tilted and fixed so as to be inclined downward from the land side to the sea side, and then the export work of loading cargo onto a ship is performed. The control method according to claim 6, wherein the main girder is tilted only when the import operation and the export operation are switched. The control method according to claim 6 or 7, wherein the maximum angle of inclination of the main girder with respect to the horizontal direction is preset by the following equation (1).

(In the formula (1), θmax is the maximum angle of inclination of the main girder with respect to the horizontal direction, Mcon is the weight of the luggage, Acc is the preset maximum acceleration of the trolley, Mt is the weight of the trolley, and g is. Gravitational acceleration).

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