Quay crane and method for controlling the same

Abstract

To provide a quay crane capable of retreating a trolley even when the trolley cannot autonomously travel.SOLUTION: This quay crane comprises: a trolley 6 configured to be movable along a horizontal member extending in a sea-land direction x; a land side catenary 7a; a sea side catenary 7b; and a rope 9 hung so as to enable the land side catenary 7a and the sea side catenary 7b to follow the movement of the trolley 6. Trolley retreating control is performed, which moves the trolley 6 to the land side by winding and delivering the rope 9 by winches 11a and 11b.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a quay crane equipped with a catenary that moves following a trolley, and a control method thereof, and more particularly to a quay crane that allows the trolley to retreat even when the trolley cannot move under its own power, and a control method thereof. [Background technology]

[0002] Various quay cranes equipped with a catenary that moves following a trolley have been proposed (see, for example, Patent Document 1). Patent Document 1 discloses the configuration of a quay crane equipped with a trolley that moves along a horizontal member extending in the sea-land direction, and a catenary that moves along the horizontal member while following the trolley. The trolley was equipped with a drive mechanism such as a motor for self-propulsion. A rope was looped between the trolley and the catenary, and this rope enabled the catenary to move to an appropriate position following the trolley.

[0003] Not only the quay crane described in Patent Document 1, but also general quay cranes have a driver's cab attached to the trolley. The crane operator sits in the cab and operates the quay crane. If the trolley becomes unable to move on its own due to a malfunction of the motor that constitutes the drive mechanism, the crane operator in the cab is unable to get off the quay crane.

[0004] In particular, when the trolley was located on the sea side of the horizontal member, the boom of the quay crane could not be raised. In this case, ships could not dock or leave the quay. Therefore, the failure of one trolley could affect the loading and unloading schedule at the container terminal. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2012-201450 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention has been made in view of the above problems, and its object is to provide a quay crane and a control method thereof that enable the trolley to be retracted even when the trolley cannot move under its own power. [Means for solving the problem]

[0007] A quay crane for achieving the above-mentioned object comprises a horizontal member extending in the land-sea direction, a trolley configured to be movable in the land-sea direction along this horizontal member, a land-side catenary arranged on the land side of the trolley and configured to be movable along the horizontal member, a sea-side catenary arranged on the sea side of the trolley and configured to be movable along the horizontal member, and a rope that is stretched around the trolley, the land-side catenary, and the sea-side catenary to cause the land-side catenary and the sea-side catenary to follow the movement of the trolley, and is characterized in that the quay crane is equipped with a retraction mechanism that retracts the trolley to the land side, and the retraction mechanism has a winch that is installed on the horizontal member and allows the rope to be wound and unwound.

[0008] A control method for a quay crane for achieving the above-mentioned object includes a horizontal member extending in the land-sea direction, a trolley configured to be movable in the land-sea direction along this horizontal member, a land-side catenary arranged on the land side of the trolley and configured to be movable along the horizontal member, a sea-side catenary arranged on the sea side of the trolley and configured to be movable along the horizontal member, and a rope that is wound around the trolley, the land-side catenary, and the sea-side catenary to cause the land-side catenary and the sea-side catenary to follow the movement of the trolley, characterized in that a winch that enables the rope to be wound in and out is installed in advance on the horizontal member, and trolley retraction control is performed to move the trolley toward land by winding and paying out the rope with the winch. [Effects of the Invention]

[0009] According to the present invention, the trolley, which cannot move on its own, can be moved to the land side by utilizing the rope and winch that are wound around the trolley, the land-side catenary, and the sea-side catenary. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is an explanatory diagram illustrating an outline of a quay crane. [Figure 2] 2 is an explanatory diagram illustrating the state of the ropes wound around the trolley and catenary in FIG. 1. FIG. [Figure 3] 3 is an explanatory diagram illustrating the state of movement of the trolley and catenary in FIG. 2 under normal conditions. FIG. [Figure 4] FIG. 3 is an explanatory diagram illustrating a state when the land-side catenary in FIG. 2 is retracted to the land side. [Figure 5] 5 is an explanatory diagram illustrating a state in which the trolley in FIG. 4 is retracted to the land side. FIG. [Figure 6] FIG. 3 is an explanatory diagram illustrating a state in which the trolley and catenary in FIG. 2 are simultaneously retracted to the land side. DETAILED DESCRIPTION OF THE INVENTION

[0011] A quay crane and its control method will be described below based on the embodiment shown in the drawings. In the drawings, the direction of travel of the quay crane is indicated by arrow y, the lateral direction that crosses this direction at a right angle is indicated by arrow x, and the up-down direction is indicated by arrow z. The lateral direction x is sometimes referred to as the sea-land direction.

[0012] As shown in Figure 1, the quay crane 1 includes a leg structure 2 and a plurality of traveling devices 3 attached to the lower end of the leg structure 2. The quay crane 1 is made up of a container crane for loading and unloading containers and an unloader for loading and unloading bulk cargo such as ore.

[0013] The leg structure 2 has a land-side leg 4a arranged on the land side in the lateral direction x (land-sea direction) and a sea-side leg 4b arranged on the sea side. The land-side leg 4a and the sea-side leg 4b are sometimes collectively referred to as legs 4. The quay crane 1 is equipped with a horizontal member 5 extending in the lateral direction x (land-sea direction). The horizontal member 5 has a girder 5a arranged on the land side and supported by the leg structure 2, and a boom 5b connected to the sea-side end of the girder 5a and extending toward the sea side.

[0014] The quay crane 1 comprises a trolley 6 configured to be movable in a lateral direction x along a horizontal member 5, a land-side catenary 7a arranged on the land side of the trolley 6 and configured to be movable along the horizontal member 5, and a sea-side catenary 7b arranged on the sea side of the trolley 6 and configured to be movable along the horizontal member 5. The land-side catenary 7a and the land-side catenary 7b are sometimes collectively referred to as catenary 7. The trolley 6 performs cargo handling operations on a ship 8 while moving in the lateral direction x along the horizontal member 5.

[0015] The land-side catenary 7a is located approximately midway between the land-side end of the horizontal member 5 and the trolley 6, and the sea-side catenary 7b is located midway between the sea-side end of the horizontal member 5 and the trolley 6. The catenary 7 is configured to support the cargo ropes that are stretched from the land-side end or sea-side end of the horizontal member 5 to the trolley 6.

[0016] As shown in Figure 2, a rope 9 is wound around the trolley 6 and the catenary 7. This rope 9 moves the catenary 7 in conjunction with the movement of the trolley 6. The rope 9 wound around the trolley 6 and the catenary 7 is a separate rope from the cargo rope supported by the catenary 7.

[0017] The quay crane 1 is equipped with a land-side inner rope 9a, one end of which is fixed to the fixed part 6a of the trolley 6 and the other end of which is fixed to the horizontal member 5 via a sheave S1 installed in the land-side catenary 7a, and a sea-side inner rope 9b, one end of which is fixed to the fixed part 6a of the trolley 6 and the other end of which is fixed to the horizontal member 5 via a sheave S2 installed in the sea-side catenary 7b. The land-side inner rope 9a and the sea-side inner rope 9b are sometimes collectively referred to as the inner ropes. Because both ends of the inner ropes 9a and 9b are fixed to the trolley 6 and the horizontal member 5, respectively, the length of the ropes themselves does not change. The location to which one end of the inner ropes 9a and 9b is fixed is not limited to the horizontal member 5, but may be any member constituting the leg structure 2. There is no difference in the function of the present invention whether one end of the inner ropes 9a and 9b is fixed to the horizontal member 5 or the leg structure 2.

[0018] The quay crane 1 is equipped with an outer rope 9c, one end of which is fixed near the land-side end of the horizontal member 5 and which passes through sheave S3 installed in the land-side catenary 7a, sheave S4 arranged near the land-side end of the horizontal member 5, sheave S5 arranged near the sea-side end of the horizontal member 5, and sheave S6 installed in the sea-side catenary 7b, in that order, and the other end of which is fixed near the sea-side end of the horizontal member 5. A pair of outer ropes 9c are tensioned on the quay crane 1, aligned in the traveling direction y. In the traveling direction y, the outer ropes 9c are tensioned on both sides of the inner ropes 9a, 9b, respectively. The configuration in which a pair of outer ropes 9c is installed makes it easier to avoid a problem in which the catenary 7 tilts about an axis in the up-down direction z when moving the catenary 7 in the lateral direction x, making movement difficult.

[0019] In this embodiment, the rope 9 that links the catenary 7 to the movement of the trolley 6 has a land-side inner rope 9a, a sea-side inner rope 9b, and a pair of outer ropes 9c. The rope 9 may also be composed of inner ropes 9a, 9b and one outer rope 9c.

[0020] The quay crane 1 is equipped with a retraction mechanism 10 that retracts the trolley 6 to the land side. In the embodiment illustrated in FIG. 2, the retraction mechanism 10 has a land-side winch 11a and a sea-side winch 11b that are fixed to the horizontal member 5. The land-side winch 11a has a configuration that allows the land-side inner rope 9a to be wound in and paid out. The sea-side winch 11b has a configuration that allows at least the sea-side inner rope 9b to be paid out. The land-side winch 11a and the sea-side winch 11b are sometimes collectively referred to as winches 11.

[0021] The winch 11 may have any configuration as long as it can wind and unwind the inner ropes 9a, 9b, and may be configured as, for example, a drum-type winch for winding the rope. The configuration of the winch 11 is not limited to a drum type, and may have any configuration that can change the length of the rope 9. For example, the winch 11 may be configured as a mechanism that has a pair of sheaves and changes the distance between the sheaves to change the length of the rope.

[0022] The winch 11 may be configured to perform only one of winding and unwinding. The winch 11 is configured to operate using the main power supply or auxiliary power supply of the quay crane 1 as a power source. The winch 11 may also be configured to operate manually.

[0023] The retraction mechanism 10 may have a second winch 12 fixed near the land-side end of the horizontal member 5. The second winch 12 has a configuration that allows at least winding of the outer rope 9c. The second winch 12 can employ a mechanism similar to that of the winch 11.

[0024] The retraction mechanism 10 may have a control unit 13 that controls the winch 11 and the second winch 12. For ease of explanation, signal lines extending from the control unit 13 to the winch 11 and the second winch 12 are shown by dashed lines in Figure 2.

[0025] The operation of the rope 9 during normal loading and unloading operations by the quay crane 1 is described below. As shown in Figure 3, when the trolley 6 moves toward the land side, it first moves toward the land side using the power of a motor or other device installed on the trolley 6. The sea-side inner rope 9b is pulled toward the land side by the trolley 6, and the sea-side catenary 7b moves toward the land side at half the speed of the trolley 6.

[0026] As the sea-side catenary 7b moves, the distance between sheave S6 installed in the sea-side catenary 7a and sheave S5 installed near the sea-side end of the horizontal member 5 increases. Because the outer rope 9c is pulled toward the sea, the distance between sheave S3 installed in the land-side catenary 7a and sheave S4 installed near the land-side end of the horizontal member 5 decreases. The land-side catenary 7a moves toward the land side at half the speed of the trolley 6. Because the land-side catenary 7a moves toward the land side along with the trolley 6, the tension in the land-side inner rope 9a is maintained. For ease of explanation, the trolley 6 and catenary 7 before movement are shown with dashed lines in Figure 3, and the control unit 13 is not shown. The direction of movement of the trolley 6 and catenary 7 is indicated by an outline arrow, and the direction of movement of the rope 9 is indicated by an arrow.

[0027] When the trolley 6 moves seaward, the land-side catenary 7a and the sea-side catenary 7b move seaward at half the speed of the trolley 6, as described above.

[0028] The operation of the rope 9 in an emergency when the trolley 6 cannot move under its own power is described below. As illustrated in Figure 4, first, land-side catenary retraction control is performed to retract the land-side catenary 7a to the land side. For example, the control unit 13 starts the land-side catenary retraction control in response to a switch operation by the crane operator.

[0029] The control unit 13 controls the second winch 12 to reel in the outer rope 9c. Normally, one end of the outer rope 9c is fixed near the land-side end of the horizontal member 5. This fixation of the outer rope 9c is released when land-side catenary retraction control begins. The second winch 12 reels in the outer rope 9c, for example, 30 m.

[0030] The control unit 13 also controls the land-side winch 11a to pay out the land-side inner rope 9a in conjunction with the winding of the outer rope 9c by the second winch 12. In this specification, "to be linked" means adjusting the amount of payout of the land-side inner rope 9a according to the amount of winding of the outer rope 9c. It is desirable that each rope 9 be operated in a state that suppresses slack in the rope 9.

[0031] For example, when the second winch 12 reels in the outer rope 9c with a length of 3L, the land-side winch 11a reels out the land-side inner rope 9a with a length of 2L, which is two-thirds of that length. This causes the land-side catenary 7a to move a distance of length L toward the land side. For the sake of explanation, the land-side catenary 7a before movement is shown in dashed lines in Figure 4. Due to the land-side catenary retraction control, only the land-side catenary 7a moves toward the land side. The trolley 6 and sea-side catenary 7b remain stopped.

[0032] The land-side winch 11a that pays out the land-side inner rope 9a does not have to be configured to receive rotational force from a motor or the like. It may be configured so that the land-side inner rope 9a is passively paid out from the land-side winch 11a as the land-side catenary 7a moves. In this case, it is desirable that the land-side winch 11a be configured to provide a predetermined resistance to the land-side inner rope 9a being paid out. This is because slack in the land-side inner rope 9a can be suppressed.

[0033] After the retraction of the land-side catenary 7a is completed, the control unit 13 starts trolley retraction control to retract the trolley 6 to the land side as illustrated in FIG.

[0034] The control unit 13 controls the land-side winch 11a to wind up the land-side inner rope 9a. The control unit 13 also controls the land-side winch 11a to reel out the sea-side inner rope 9b by the sea-side winch 11b in conjunction with the reeling of the land-side inner rope 9a. The reeling amount of the sea-side inner rope 9b is adjusted according to the reeling amount of the land-side inner rope 9a.

[0035] For example, when the land-side winch 11a winds up the land-side inner rope 9a of length 2L, the sea-side winch 11b unwinds the sea-side inner rope 9b of the same length 2L. This causes the trolley 6 to move a distance of length L toward the land side. It is desirable that each winch 11a, 11b be controlled so that neither the land-side inner rope 9a nor the sea-side inner rope 9b is significantly slack.

[0036] The land-side winch 11a and the sea-side winch 11b are linked together, causing the trolley 6 to move toward the land side. For the sake of explanation, the trolley 6 before movement is shown in dashed lines in Figure 5. Only the trolley 6 moves toward the land side due to trolley retraction control. The land-side catenary 7a and the sea-side catenary 7b remain stopped.

[0037] The sea side winch 11b does not have to have a configuration in which a rotational force is applied by a motor etc. The sea side inner rope 9b may be passively paid out from the sea side winch 11b by the movement of the trolley 6.

[0038] By using the trolley retraction control, the trolley 6 can be retracted to the vicinity of the sea-side leg 4b or the land-side leg 4a. The crane operator in the driver's cab attached to the trolley 6 can descend from the quay crane 1 using the stairs or elevator installed on the leg 4.

[0039] Since the trolley 6 can be retracted from the boom 5b to the land-side girder 5a, the quay crane 1 can execute control to raise the boom 5b. This makes it possible to perform work such as docking and undocking of the ship 8. Furthermore, with the boom 5b raised, the quay crane 1 can be driven to a repair area to perform repairs, etc. When the boom 5b is in a collapsed state, it is difficult to drive the quay crane 1 because the bridge of the ship 8 interferes with the boom 5b.

[0040] The rope 9 is normally used to operate the quay crane 1, making it easy to detect malfunctions. The retraction mechanism 10 uses this rope 9 to perform trolley retraction control, making it possible to reliably retract the trolley 6 when necessary.

[0041] The land-side catenary retraction control is not a mandatory requirement. If there is space on the land side where the trolley 6 can be retracted, the trolley 6 can be retracted without retracting the land-side catenary 7a. In addition, the trolley 6, which is moving due to the trolley retraction control, may be configured to push the land-side catenary 7a toward the land side.

[0042] The configuration for executing land-side catenary retraction control can avoid the problem of the land-side catenary 7a hindering the retraction of the trolley 6. In addition, it is possible to smoothly move the trolley 6 during trolley retraction control.

[0043] The control unit 13 is not an essential requirement. The winch 11 and the second winch 12 may be configured to be manually controlled by an operator operating a switch, etc. Also, the winch 11 and the second winch 12 may be configured to have a rotational force applied thereto by human power.

[0044] The winch 11 and the second winch 12 are configured to be permanently installed on the quay crane 1. The winch 11 and the second winch 12 may also be configured to be installed at a position rearward of the fixed ends of each rope 9. For example, the winch 11 can be located above the fixed ends of the inner ropes 9a and 9b at the end where the inner ropes 9a and 9b are fixed to the horizontal member 5. Also, the second winch 12 can be located on the landward end of the outer rope 9c, closer to the land than the fixed end of the outer rope 9c. This configuration prevents the tension of the ropes 9 from acting on the winch 11 and other components under normal circumstances. This is advantageous for suppressing deterioration of the winch 11 and other components.

[0045] The winch 11 and the second winch 12 may be configured to be installed in the middle of each rope 9 rather than at the end of each rope 9. The winch 11 and the like may have a configuration that allows the length of each rope 9 to be changed.

[0046] The winch 11 and the second winch 12 may be configured to be installed in an emergency rather than being permanently installed. The winch 11 and the second winch 12 may be configured to be connected to the ropes 9 by workers or the like in an emergency.

[0047] The configuration of the rope 9 stretched on the trolley 6 and catenary 7 of the quay crane 1 is not limited to the above. The inner ropes 9a, 9b and outer rope 9c that make up the rope 9 may be stretched in a state different from that of the embodiment illustrated in Fig. 5. For example, as seen in Japanese Patent Application Laid-Open No. 2000-136086, if there is a rope for connecting the trolley and catenary, it is possible to use this rope to retract the trolley to the land side.

[0048] A configuration may be adopted in which the land-side catenary retraction control and the trolley retraction control are executed simultaneously, as illustrated in Figure 6. In this embodiment, the second winch 12 reels in the outer rope 9c, and the sea-side winch 11b pays out the sea-side inner rope 9b.

[0049] When the second winch 12 reels in the outer rope 9c, the distance in the lateral direction x between the sheave S4 installed near the land-side end of the horizontal member 5 and the sheave S3 installed in the land-side catenary 7a decreases. As a result, the land-side catenary 7a moves toward the land side. Since the length of the land-side inner rope 9a does not change, the trolley 6 moves toward the land side in response to the land-side catenary 7a's movement toward the land side.

[0050] In this embodiment, there is no need to control the length of the land-side inner rope 9a, and therefore the land-side winch 11a is not required. [Explanation of symbols]

[0051] 1 Quay crane 2 leg structure 3 Running gear 4 legs 4a Land leg 4b sea side leg 5 Horizontal members 5a Guarda 5b Boom 6 Trolley 6a Fixed part 7 Catenary 7a Landside catenary 7b Seaside catenary 8 Ships 9. Rope 9a Land side inner rope 9b Seaside inner rope 9c Outer Rope 10 Evacuation mechanism 11. Winch 11a Land side winch 11b Seaside winch 12 Second winch 13 Control Unit x transverse direction y Travel direction z Vertical direction S sieve S1, S3 Sheaves installed on the land side catenary S2, S6 Sheaves installed on the seaside catenary S4 Sheaves located near the landward end of the horizontal member S5 Sheaves located near the seaward end of the horizontal member

Claims

1. A quay crane comprising a horizontal member extending in the land-sea direction, a trolley configured to be movable in the land-sea direction along the horizontal member, a land-side catenary arranged on the land side of the trolley and configured to be movable along the horizontal member, a sea-side catenary arranged on the sea side of the trolley and configured to be movable along the horizontal member, and a rope that is reeled around the trolley, the land-side catenary, and the sea-side catenary to cause the land-side catenary and the sea-side catenary to follow the movement of the trolley, Equipped with a retraction mechanism that retracts the trolley to the land side, 10. A quay crane according to claim 9, wherein the retraction mechanism has a winch installed on the horizontal member for enabling winding and unwinding of the rope.

2. The rope has a land-side inner rope, one end of which is fixed to the trolley and the other end of which is fixed to the horizontal member via a sheave installed on the land-side catenary, and a sea-side inner rope, one end of which is fixed to the trolley and the other end of which is fixed to the horizontal member via a sheave installed on the sea-side catenary, 2. A quay crane according to claim 1, wherein the winches include a land-side winch that is installed on the horizontal member and enables winding and unwinding of the land-side inner rope, and a sea-side winch that is installed on the horizontal member and enables unwinding of the sea-side inner rope.

3. The rope has one end fixed to the vicinity of the land side end of the horizontal member, and has an outer rope whose other end is fixed to the vicinity of the sea side end of the horizontal member, passing through a sheave installed on the land side catenary, a sheave arranged near the land side end of the horizontal member, a sheave arranged near the sea side end of the horizontal member, and a sheave installed on the sea side catenary in this order, 3. A quay crane according to claim 2, wherein the winch further comprises a second winch arranged near the land-side end of the horizontal member to enable winding of the outer rope.

4. The retraction mechanism has a control unit, a catenary retraction control that moves the land-side catenary to the land side by interlocking the winding of the outer rope by the second winch and the payout of the land-side inner rope by the land-side winch; 4. The quay crane according to claim 3, wherein the control unit is configured to perform trolley retraction control to move the trolley to the land side by linking the winding of the land side inner rope by the land side winch and the unwinding of the sea side inner rope by the sea side winch.

5. A method for controlling a quay crane comprising: a horizontal member extending in the land-sea direction; a trolley configured to be movable in the land-sea direction along the horizontal member; a land-side catenary arranged on the land side of the trolley and configured to be movable along the horizontal member; a sea-side catenary arranged on the sea side of the trolley and configured to be movable along the horizontal member; and a rope that is reeled around the trolley, the land-side catenary, and the sea-side catenary to cause the land-side catenary and the sea-side catenary to follow the movement of the trolley, A winch that can wind and unwind the rope is installed in advance on the horizontal member, A method for controlling a quay crane, characterized in that trolley retraction control is performed to move the trolley toward land by winding and unwinding the rope with the winch.

6. The ropes are previously installed as follows: a land-side inner rope, one end of which is fixed to the trolley and the other end of which is fixed to the horizontal member via a sheave installed on the land-side catenary; and a sea-side inner rope, one end of which is fixed to the trolley and the other end of which is fixed to the horizontal member via a sheave installed on the sea-side catenary. a land-side winch that is installed on the horizontal member and that enables winding and unwinding of the land-side inner rope, and a sea-side winch that is installed on the horizontal member and that enables unwinding of the sea-side inner rope are installed in advance as the winches, 6. A quay crane control method according to claim 5, wherein the trolley retraction control is performed by winding up the land-side inner rope with the land-side winch and letting out the sea-side inner rope with the sea-side winch.

7. an outer rope having one end fixed to the vicinity of the land-side end of the horizontal member, passing through a sheave installed on the land-side catenary, a sheave arranged in the vicinity of the land-side end of the horizontal member, a sheave arranged in the vicinity of the sea-side end of the horizontal member, and a sheave installed on the sea-side catenary in this order, and having the other end fixed to the vicinity of the sea-side end of the horizontal member; A second winch is provided in advance as the winch, the second winch being disposed near the land-side end of the horizontal member and capable of winding up the outer rope, A quay crane control method according to claim 6, wherein catenary retraction control is performed to move the land-side catenary toward the land side by winding up the outer rope with the second winch and letting out the land-side inner rope with the land-side winch.

8. The method for controlling a quay crane according to claim 7, wherein the trolley retraction control is performed after the catenary retraction control is performed.

9. a land-side inner rope having one end fixed to the trolley and the other end fixed to the horizontal member via a sheave installed on the land-side catenary; and a sea-side inner rope having one end fixed to the trolley and the other end fixed to the horizontal member via a sheave installed on the sea-side catenary. an outer rope having one end fixed to the vicinity of the land-side end of the horizontal member, passing through a sheave installed on the land-side catenary, a sheave arranged in the vicinity of the land-side end of the horizontal member, a sheave arranged in the vicinity of the sea-side end of the horizontal member, and a sheave installed on the sea-side catenary in this order, and having the other end fixed to the vicinity of the sea-side end of the horizontal member; a sea-side winch that is installed on the horizontal member and enables the sea-side inner rope to be let out, and a second winch that is arranged near the land-side end of the horizontal member and enables the outer rope to be wound up, A quay crane control method according to claim 5, wherein catenary retraction control for moving the land-side catenary to the land side and the trolley retraction control are performed by winding up the outer rope with the second winch and letting out the sea-side inner rope with the sea-side winch.

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