Slinging method, operating device and hook device

Abstract

To provide a slinging method capable of realizing slinging work using an underwater robot, an operation device capable of realizing engagement / engagement release of the underwater robot with respect to an engagement object with a simple configuration, and a hook device suitable for the slinging work using the underwater robot.SOLUTION: A hook device 6 is held with the use of an underwater robot 4 by rotating a hand of the underwater robot to make the hand take an engaged posture (step S3). Thereafter, by moving the underwater robot holding the hook device to engage the slinging hook 31 with an underwater structure, a slinging rope 2 is hooked on the underwater structure (step S5). After the engagement of the slinging hook to the underwater structure, the hand is rotated to take a detachment posture so that the holding of the hook device with the underwater robot is released (step S6).SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a slinging method, an operating device, and a hook device. [Background technology]

[0002] Lifting and moving of underwater structures (concrete blocks, etc.) placed underwater is carried out by connecting a sling hook to the underwater structure and lifting this sling hook with a crane mounted on a work vessel, etc. Therefore, when lifting or moving an underwater structure, it is necessary to perform the work of connecting (hanging) the sling hook, to which a sling rope extending from the crane is connected, to the underwater structure, i.e., slinging work.

[0003] Conventionally, rigging work has been carried out manually by divers. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2017-007845 A (paragraphs 0002-0004, Figure 7) Summary of the Invention [Problem to be solved by the invention]

[0005] However, slinging work by divers is dangerous work as there is a risk of their fingers or other parts of their body getting caught in the sling hook or underwater structure. As a result, there are concerns that manual slinging work by divers does not adequately guarantee the safety of the divers. Therefore, studies are being conducted to perform underwater slinging work without the involvement of divers.

[0006] The inventors of the present application are considering performing slinging operations using an underwater robot. It is desirable that slinging operations using an underwater robot be performed smoothly. When engaging an underwater robot with an engagement target, it is desirable that the engagement / disengagement of the underwater robot with the engagement target be achieved with a simple configuration. It is therefore desirable to provide a hook device suitable for such slinging operations.

[0007] Therefore, one object of the present invention is to provide a slinging method that can realize slinging work using an underwater robot.

[0008] Another object of the present invention is to provide an operating device that can realize engagement / disengagement of an underwater robot with an engagement object with a simple configuration.

[0009] Another object of the present invention is to provide a hook device suitable for slinging operations using an underwater robot. [Means for solving the problem]

[0010] A first aspect of the present invention provides a slinging method for attaching a sling rope to an underwater structure placed underwater, the method comprising: a hook device holding step in which a hook device having a sling hook and an engagement rod, the sling rope being connected, is held by the underwater robot by rotating a hand of the underwater robot, the hand having a plurality of hook-shaped claws spaced apart along a rotation axis, about the rotation axis to place the hand in an engagement position where the engagement rod and the hook-shaped claws can engage with each other; a sling hook engaging step in which the underwater robot holding the hook device engages with the underwater structure by moving the underwater robot holding the hook device and engaging the sling hook with the underwater structure; and a hold release step in which, after the sling hook has engaged with the underwater structure, the hand is rotated about the rotation axis to place the hand in a release position where the engagement rod can be released from the hook-shaped claws, thereby releasing the hold of the hook device by the underwater robot.

[0011] In one embodiment of the present invention, the slinging method further includes an evacuation process in which the underwater robot is evacuated from the hook device after the hook device has released its hold, and a lifting process in which the underwater structure is raised by lifting the sling hook via the sling rope after the underwater robot has been evacuated.

[0012] In one embodiment of the present invention, the slinging method further includes, prior to the hook device holding step, a hook device underwater dropping step of dropping the hook device, with the sling rope connected to the sling hook, into water.

[0013] A second aspect of the present invention provides an operating device mounted on an underwater robot, the operating device including a hand rotatable around a predetermined rotation axis, the hand having a plurality of hooked claws spaced apart along the rotation axis, and a rotation unit that rotates the hand around the rotation axis, wherein the rotation unit rotates the hand around the rotation axis, causing the hand to change position between an engagement position in which the engagement rod and the hooked claws can engage with each other, and a disengagement position in which the engagement rod can disengage from the hooked claws.

[0014] In one embodiment of the present invention, the engagement position of the hand is a position in which the inner surface of each hooked claw faces upward, and the release position of the hand is a position in which the inner surface of each hooked claw faces downward.

[0015] In one embodiment of the present invention, at least two hooked claws included in the hand have inner surfaces formed with fitting grooves into which the engagement rods fit.

[0016] In one embodiment of the present invention, a fitting groove into which the engaging rod fits is formed on the inner surface of every hook-shaped claw included in the hand.

[0017] A third aspect of the present invention provides a hook device for attaching a sling rope to an underwater structure located underwater, the hook device including a float, a sling hook coupled to one side of the float and to which the sling rope is connected, and an engagement rod coupled to the other side of the float opposite to the one side.

[0018] In one embodiment of the present invention, the float is hollow box-shaped, the engaging rod is connected to one side of the float, and the sling hook is connected to the opposite side of the float opposite the one side.

[0019] In one embodiment of the present invention, the hollow box-shaped float has a longitudinal direction, and the engaging rod extends along the longitudinal direction of the float.

[0020] In one embodiment of the present invention, the hollow box-shaped float has a longitudinal direction, and the sling hook is disposed at the center of the float in the width direction.

[0021] In one embodiment of the present invention, the engaging rod includes a rod portion and a pair of connecting portions that connect both ends of the rod portion to the floating body.

[0022] In one embodiment of the present invention, the sling hook includes a hook-shaped hook body and a tip tool that is detachable from a tip end of the hook body. With the tip tool attached to the tip end of the hook body, the tip tool extends so that the shortest distance between the tip end and the one surface increases toward the tip end of the tip tool.

[0023] In one embodiment of the present invention, the tip tool is made of an elastic body that is elastically deformable.

[0024] In one embodiment of the present invention, the float has a longitudinal direction, and the tip of the sling hook protrudes toward one end of the longitudinal direction of the float.

[0025] In one embodiment of the present invention, the sling hook and the floating body are separably connected to each other.

[0026] In one embodiment of the present invention, a float rope member different from the sling rope is connected to the engaging hook.

[0027] A fourth aspect of the present invention provides an underwater robot including a hand rotatable around a predetermined rotation axis, the hand having a plurality of hooked claws spaced apart along the rotation axis, and a rotation unit that rotates the hand around the rotation axis, wherein the rotation unit rotates the hand around the rotation axis, causing the hand to change position between an engaged position in which the hand can support an engaging rod from below, and a disengaged position in which the hand cannot support the engaging rod. [Effects of the Invention]

[0028] According to a first aspect of the present invention, the underwater robot holds the hook device by rotating the hand of the underwater robot to engage the engagement rod and hooked claw of the hook device, thereby smoothly achieving holding of the hook device. Furthermore, the underwater robot holding the hook device moves to engage the sling hook of the hook device with the underwater structure, thereby connecting (hanging) the sling rope to the underwater structure. After the sling hook engages with the underwater structure, the hand is rotated to disengage the engagement rod and hooked claw, thereby releasing the hold of the hook device by the underwater robot. As described above, slinging operations using an underwater robot can be smoothly achieved by a series of operations: holding the hook device, engaging the sling hook, and releasing the hold of the hook device.

[0029] According to a second aspect of the present invention, the underwater robot can switch between engaging and disengaging with an engaging object by rotating the hand of the underwater robot to change the position of the hand between an engaging position and a disengaging position. Therefore, the underwater robot can be engaged / disengaged with an engaging object with a simple configuration.

[0030] According to a third aspect of the present invention, the hook device includes an engagement rod in addition to the float and the sling hook. By engaging the engagement rod with the underwater robot, the hook device can be smoothly held by the underwater robot. This provides a hook device suitable for slinging operations using an underwater robot. [Brief explanation of the drawings]

[0031] [Figure 1] FIG. 1 is a side view showing a configuration of a slinging system used in a slinging method according to an embodiment of the present invention. [Figure 2] FIG. 2 is a perspective view showing the configuration of the underwater robot shown in FIG. [Figure 3A] 3 is an enlarged perspective view showing the operating device shown in FIG. 2. FIG. [Figure 3B] FIG. 3B is an enlarged perspective view showing the configuration in which a rotation unit and a restriction rod are removed from FIG. 3A. [Figure 4] FIG. 2 is a block diagram showing an electrical configuration of the sling system. [Figure 5A] 2 is an enlarged perspective view showing the configuration of the hook device shown in FIG. 1. FIG. [Figure 5B] FIG. 2 is an enlarged perspective view showing the configuration of the hook device. [Figure 6] FIG. 4 is a diagram showing a flow of the slinging method. [Figure 7] FIG. 7 is a perspective view showing a state before step S3 in FIG. 6. [Figure 8] FIG. 7 is a side view for explaining the step S3 in FIG. 6. [Figure 9] FIG. 9 is a side view for explaining the step subsequent to that in FIG. 8. [Figure 10] FIG. 10 is a side view for explaining the step subsequent to that in FIG. 9. [Figure 11] FIG. 7 is a side view for explaining the step S4 in FIG. 6. [Figure 12] FIG. 7 is a cross-sectional view for explaining the step S5 of FIG. 6. [Figure 13]FIG. 7 is a cross-sectional view showing the state after step S7 in FIG. [Figure 14] 10A and 10B are diagrams illustrating a modified example of a tip attachment of the hook device. DETAILED DESCRIPTION OF THE INVENTION

[0032] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0033] FIG. 1 is a side view showing the configuration of a slinging system 1 used in a slinging method according to one embodiment of the present invention.

[0034] The slinging method is a method of connecting (hanging) a sling hook 31, to which a sling rope 2 extending from a crane mounted on a work vessel or the like is connected, to an underwater structure 3 located underwater (in the sea). Then, by lifting the sling hook 31 connected to the underwater structure 3 with a crane, the underwater structure 3 is raised or moved.

[0035] The underwater structure 3 is, for example, a concrete block. Examples of concrete blocks include wave-dissipating blocks. The underwater structure 3 is, for example, a rectangular parallelepiped. The underwater structure 3 is, for example, a square in plan view. The height of the underwater structure 3 shown in the example of Figure 1 is one example. The height of the underwater structure 3 may be equal to or greater than one side of the planar shape of the underwater structure 3.

[0036] A groove 3b having, for example, a rectangular shape in plan view is formed on the top surface 3a of the underwater structure 3. A hook portion 61 having a 180° inverted U-shape is arranged inside the groove 3b. The cross section of the hook portion 61 is circular. Both ends of the hook portion 61 are fixed to the flat bottom surface of the groove 3b. An upper end 61a of the hook portion 61, located in the center of the hook portion 61, is either flush with the top surface 3a of the underwater structure 3 or is located lower than the top surface 3a. Because the 180° inverted U-shaped hook portion 61 is retracted from the top surface 3a of the underwater structure 3, multiple underwater structures 3 can be stacked one on top of the other.

[0037] A slinging system 1 used in the slinging method includes a sling rope 2, an underwater robot 4, a display operation unit 5 (see FIG. 4), and a hook device 6. The hook device 6 is provided with a sling hook 31.

[0038] FIG. 2 is a perspective view showing the configuration of the underwater robot 4. FIG. 3A is an enlarged perspective view showing the operating device 12. FIG. 3B is an enlarged perspective view showing the configuration of FIG. 3A with the rotary unit 21 and the regulating rod 24 removed. FIG. 4 is a block diagram showing the electrical configuration of the sling system 1. The underwater robot 4 will be described with reference to FIGS. 2 to 4.

[0039] The underwater robot 4 is a robot that can be operated by remote control, such as an ROV (Remotely Operated Vehicle). Such an underwater robot is sometimes called an underwater drone.

[0040] As shown in FIGS. 2 to 4, the underwater robot 4 includes a robot body 11 and an operating device 12 mounted on the robot body 11.

[0041] As shown in Figures 2 and 4, the robot body 11 includes a main body frame 13, a camera 14 for photographing underwater, multiple lights 15 for illuminating the front of the underwater robot 4 and the subject to be photographed, multiple propellers 16 for generating propulsion to move the underwater robot 4, a control device 17 for controlling the operation of the underwater robot 4, a battery 18 that functions as a power source for driving the underwater robot 4, and a communication unit 19 for communicating with the display operation unit 5.

[0042] 2, the multiple propellers 16 include one or more up-and-down movement propellers 16A for generating propulsive force to move the underwater robot 4 up and down underwater, and forward / backward / left-right movement propellers 16B for generating propulsive force to move the underwater robot 4 in the forward / backward and left-right directions underwater. Therefore, the underwater robot 4 can rise and descend underwater, and can move in the forward / backward directions (forward direction FD and backward direction BD) and left-right directions (lateral movement).

[0043] As shown in Fig. 4, the control device 17 is configured using a computer (for example, a microcomputer equipped with a calculation unit such as a CPU, a storage device, a timer, etc.). The communication unit 19 communicates with the communication unit 30 of the display operation unit 5 via a wired cable (for example, an optical fiber cable). The camera 14, the plurality of lights 15, the plurality of propellers 16, the control device 17, the battery 18, and the communication unit 19 are mounted on the main body frame 13.

[0044] As shown in Figure 2, the operating device 12 mounted on the underwater robot 4 is a device for holding the hook device 6. The operating device 12 is equipped with a hand 23 that can engage with an engagement rod 33 (described later) of the hook device 6, and by changing the posture of the hand 23, the operating device 12 can hold the hook device 6 or release the hold of the hook device 6.

[0045] As shown in FIGS. 3A and 3B, the operating device 12 includes a device frame 20, a rotation unit 21, a rotation shaft 22, a hand 23 that rotates in association with the rotation of the rotation shaft 22, and a regulating rod 24.

[0046] The equipment frame 20 is detachably attached to the lower part of the robot body 11 of the underwater robot 4. The equipment frame 20 has a pair of front and rear frame rods 20A, 20B connected to the lower part of the robot body 11.

[0047] The rotary unit 21 is, for example, an electric motor. The electric motor is capable of rotating forward and reverse. The electric motor is oriented such that its output shaft is aligned with the forward and backward directions FD and BD of the underwater robot 4. A drive gear 21A is fitted onto the output shaft of the electric motor so as to rotate integrally therewith.

[0048] The rotating shaft 22 connects the pair of frame rods 20A, 20B in the front and rear. The rotating shaft 22 is rotatably supported relative to the pair of frame rods 20A, 20B. The rotating shaft 22 extends along the front-to-rear directions FD, BD of the underwater robot 4. The central axis of the rotating shaft 22 is the rotation axis C. A driven gear 22A is fitted onto the rotating shaft 22 so as to rotate integrally therewith. The driven gear 22A is in mesh with the drive gear 21A.

[0049] 3A and 3B, the hand 23 is a comb-like hand. The hand 23 has a plurality of (for example, four) hooked claws 25 spaced apart along the rotation shaft 22. The base end 25a of each hooked claw 25 is connected to the rotation shaft 22 so as to be integrally rotatable. In this embodiment, the plurality of hooked claws 25 have the same specifications (the same shape and size). The plurality of hooked claws 25 are aligned when viewed from the axial direction of the rotation shaft 22. In other words, the phases of the hooked claws 25 relative to the rotation direction of the rotation shaft 22 are aligned. In this embodiment, the axial distance W1 between adjacent hooked claws 25 is equal to one another. The distance W1 between adjacent hooked claws 25 is sufficiently larger than the axial size of the hooked claws 25. The interval W1 between adjacent hook-shaped claws 25 is greater than the length of a connecting portion 52 of the engagement rod 33 in the longitudinal direction X, which will be described later.

[0050] 3A and 3B, the restriction rod 24 is adjacent to the rotation shaft 22 in the lateral direction and extends parallel to the rotation shaft 22. The restriction rod 24 has a generally rectangular cross section. A side surface of the restriction rod 24 is an opposing surface 24a (see FIGS. 8 to 11) that faces the outer periphery of the rotation shaft 22. The restriction rod 24 abuts against the rod portion 51 of the engaging rod 33 that attempts to disengage from the hand 23 in the engagement posture P1 (see FIGS. 3A, 3B, and 11), thereby suppressing or preventing the rod portion 51 from coming off the hand 23 in the engagement posture P1.

[0051] 3A and 3B, a fitting groove 26 into which an engaging rod 33 (described later) fits is formed on the inner surface 25c of each of the hooked claws 25. The fitting groove 26 is disposed near the base end 25a of each of the hooked claws 25. The fitting groove 26 is substantially semicircular. The maximum depth of the fitting groove 26 is smaller than the size of the rod portion 51 of the engaging rod 33 in the width direction Y and is greater than half the size of the rod portion 51 in the width direction Y.

[0052] When the output shaft of the rotation unit 21 rotates in a predetermined direction, the rotation shaft 22 rotates in the predetermined direction via the drive gear 21A and the driven gear 22A. When the output shaft of the rotation unit 21 rotates in the opposite direction, the rotation shaft 22 rotates in the opposite direction via the drive gear 21A and the driven gear 22A.

[0053] The rotating unit 21 rotates the hand 23 around the rotation axis C, whereby the hand 23 changes its position between an engagement position P1 (see FIGS. 3A, 3B, and 11) in which the engagement rod 33 and the hooked claws 25 can engage with each other, and a disengagement position P2 (see FIG. 8) in which the engagement rod 33 can disengage from the hooked claws 25. In this embodiment, the engagement position P1 of the hand 23 is a position in which the inner surface 25c of each hooked claw 25 faces upward, and the disengagement position P2 of the hand 23 is a position in which the inner surface 25c of each hooked claw 25 faces downward.

[0054] The underwater robot 4 is remotely controlled by an operator on board a work boat or the like operating the display operation unit 5. Specifically, by operating the display operation unit 5, the underwater robot 4 can be moved forward, the direction of travel of the underwater robot 4 can be changed, and the posture of the underwater robot 4 can be changed. The posture of the hand 23 of the underwater robot 4 can also be changed by operating the display operation unit 5. The operator remotely controls the underwater robot 4 by operating the operation unit 29 while looking at the display unit 28 of the display operation unit 5.

[0055] As shown in Fig. 4, the display operation unit 5 includes a control device 27, a display section 28 including a monitor, etc., an operation section 29 including input keys, etc., and a communication section 30. The control device 27 is composed of a microcomputer equipped with a calculation section such as a CPU, a storage device, a timer, etc. The communication section 30 communicates with the communication section 19 of the underwater robot 4 via a wired cable (for example, an optical fiber cable).

[0056] The underwater robot 4 also includes a sonar sensor for measuring the distance to the bottom 101 and the underwater topography, a depth sensor for measuring the water depth, a GPS receiver for measuring the position, an electronic compass for measuring the direction, and the like.

[0057] 5A and 5B are enlarged perspective views showing the configuration of the hook device 6. Figures 5A and 5B show the hook device 6 viewed from different angles. The hook device 6 will be described with reference to Figures 5A and 5B.

[0058] The hook device 6 is a device for lashing the sling rope 2 to the underwater structure 3 located underwater. The hook device 6 comprises a floating body 32, a sling hook 31, and an engagement rod 33, which are connected to one another. The sling hook 31 is connected to one side of the floating body 32 (the lower side in FIGS. 5A and 5B). The engagement rod 33 is connected to the other side of the floating body 32 (the upper side in FIGS. 5A and 5B).

[0059] The floating body 32 includes a hollow box 34. The hollow box 34 is a rectangular housing having a longitudinal direction. The longitudinal direction of the hollow box 34 is defined as a longitudinal direction X. One side of the longitudinal direction X is defined as one direction X1, and the opposite side to the one direction X1 is defined as the other direction X2.

[0060] The outer wall of the hollow box 34 is formed using, for example, a metal material. The hollow box 34 has one side 34a (the surface diagonally downward to the left in FIGS. 5A and 5B ) and another side 34b (the surface diagonally upward to the right in FIGS. 5A and 5B ) opposite to the one side 34a. The slinging hook 31 is connected to the one side 34a. The engaging rod 33 is connected to the other side 34b. Although not shown, the one side 34a is formed with a fitting groove having an inner wall shaped to fit along the outer wall of the upper part of the rope connecting portion 42 of the slinging hook 31 and the outer wall of the upper part of the base end 41a. When the upper part of the rope connecting portion 42 and the upper part of the base end 41a are fitted into the fitting groove, the slinging hook 31 and the float 32 are connected together.

[0061] 5A and 5B show a hollow box 34 having two divided boxes 35 connected in the longitudinal direction X. In FIGS. 5A and 5B, the two divided boxes 35 have the same specifications. The two divided boxes 35 are connected to each other using, for example, a metal connecting rod 36 (see FIG. 1).

[0062] 5A and 5B, the engagement rod 33 and the connecting rod 36 are configured by a rectangular ring 37 having a longitudinal axis. That is, the engagement rod 33 and the connecting rod 36 are formed integrally. Specifically, the engagement rod 33 is configured by three sides of the square ring 37 except for one longitudinal side. One longitudinal side is embedded in the two separate boxes 35. The connecting rod 36 is configured by the portion of the longitudinal side that is exposed between the two separate boxes 35.

[0063] As shown in Figures 5A and 5B, the sling hook 31 comprises a hook-shaped (U-shaped) hook main body 41, a rope connecting portion 42 including an eye ring or the like connected to one end of the sling rope 2, and a tip attachment (tip tool) 43.

[0064] The hook main body 41 has a base end 41a connected to the rope connecting part 42, and a tip end 41b. An opening is formed between the base end 41a and the tip end 41b. The hook main body 41 and the rope connecting part 42 are integrally formed using a metal material such as steel.

[0065] The tip attachment 43 is an attachment that is attached to the tip portion 41b of the hook main body 41, and is formed using an elastic material that is elastically deformable, such as rubber. The tip attachment 43 is an extension attachment that extends the tip portion 41b of the hook main body 41. The tip attachment 43 is detachable from the hook main body 41, and the tip attachment 43 and the hook main body 41 are firmly joined together by fasteners such as bolts.

[0066] The tip attachment 43 extends in a generally rod-like shape. The tip attachment 43 has a base end 43a and a tip end 43b. With the base end 43a of the tip attachment 43 attached to the tip end 41b of the hook main body 41, the tip attachment 43 extends in a direction inclined with respect to the longitudinal direction X of the float 32. Specifically, the tip attachment 43 extends such that the shortest distance between the tip attachment 43 and one surface 34a of the float 32 increases toward the tip end 43b of the tip attachment 43. The entrance of the sling hook 31 is defined by the space between the tip end 43b of the tip attachment 43 and the rope connecting portion 42 (the base end of the sling hook 31). Because the tip attachment 43 extends such that the shortest distance between the tip attachment 43 and one surface 34a increases toward the tip end 43b, the entrance of the sling hook 31 is secured wide.

[0067] 5A and 5B, the sling hook 31 further includes a retaining metal fitting 45 for closing an opening formed between the base end 41a and the tip end 41b. The retaining metal fitting 45 is attached to the base end 41a of the hook body 41. The retaining metal fitting 45 has a base end 45a and a tip end 45b. The base end 45a of the retaining metal fitting 45 is attached to the base end 41a of the hook body 41.

[0068] The position of the anti-detachment fitting 45 can be changed between a closed position (see FIGS. 5A and 5B) in which the tip 45b of the anti-detachment fitting 45 approaches or abuts against the tip 41b of the hook body 41, thereby closing the opening, and an open position in which the tip 45b of the anti-detachment fitting 45 moves away from the tip 41b of the hook body 41, thereby opening the opening. The sling hook 31 further includes a biasing unit (not shown) equipped with a spring or the like, which biases the anti-detachment fitting 45 in the direction of the closed position. Therefore, the anti-detachment fitting 45 is normally in the closed position.

[0069] As described above, the sling hook 31 is connected to one surface 34a of the floating body 32. The base end 41a of the hook body 41 of the sling hook 31 is connected to the one surface 34a. They are connected at one or more locations (two locations in the example of Figures 5A and 5B) by joining with joining tape 38. Both ends of the joining tape 38 are fixed to the one surface 34a. The sling hook 31 is fastened to the floating body 32 by the binding force of the joining tape 38. The fixing force of the joining tape 38 to the one surface 34a is not very strong. In other words, the sling hook 31 is detachably connected to the floating body 32.

[0070] When the sling hook 31 and the float 32 are connected, the tip 31a of the sling hook 31 protrudes in one direction X1 relative to one end 32a of the float 32 in the longitudinal direction X. In other words, the tip 31a of the sling hook 31 is retracted in the other direction X2 relative to one end 32a of the float 32.

[0071] 5A and 5B, the engaging rod 33 includes a rod-shaped rod portion 51 and a pair of connecting portions 52 that connect both ends 51a, 51b of the rod portion 51 to the float 32. The rod portion 51 and the pair of connecting portions 52 are integrally formed using a metal material such as steel. The rod portion 51 extends along the longitudinal direction X.

[0072] The pair of connecting parts 52 are respectively coupled to the other surface 34b of the float 32 at a position near one end 32a, which is an end of the float 32 in one direction X1, and at a position near the other end 32b, which is an end of the float 32 in the other direction X2. The pair of connecting parts 52 are fixed to the other surface 34b of the float 32 by welding or the like.

[0073] In the hook device 6, the size of the float 32 is adjusted so that the buoyancy generated in the float 32 in the water (under the sea) is slightly smaller than the gravity generated in the hook device 6 (the sling hook 31, the float 32, and the engagement rod 33). Therefore, the hook device 6 sinks in the water (under the sea).

[0074] As shown in Figures 5A and 5B, the sling rope 2 is a rope suspended in water from the winch of a crane mounted on a work vessel or the like. The sling rope 2 is preferably a metal sling wire rope from the standpoint of strength, but may also be a fiber wire rope made of fiber (synthetic fiber or natural fiber). The sling wire rope may be of a locking type or a braided type. One end of the sling rope 2 is connected to a sling hook 31 as described below. The other end of the sling rope 2 is connected to the winch of a crane mounted on the work vessel or the like.

[0075] FIG. 6 is a diagram showing the flow of a slinging method using the slinging system 1. FIG. 7 is a perspective view showing the state before step S3 in FIG. 6. FIGS. 8 to 10 are side views for explaining step S3 in FIG. 6. FIG. 11 is a side view for explaining step S4 in FIG. 6. FIG. 12 is a cross-sectional view for explaining step S5 in FIG. 6. FIG. 13 is a cross-sectional view showing the state after step S7 in FIG. 6.

[0076] The flow of the slinging method will be described with reference to Figures 6 to 13. Figures 1 to 5B will also be referenced as appropriate.

[0077] A slinging method using the slinging system 1 is performed using a work boat or the like in a water area (ocean area) where the underwater structure 3 is to be raised or moved. In this slinging method, a hook device 6 is dropped into the water from a work boat or the like (S2 in FIG. 6), and the hook device 6 that has landed on the water bottom 101 is captured and held by the underwater robot 4 (S3 in FIG. 6: hook device holding step). The underwater robot 4 is then moved to approach the underwater structure 3 to be slinged (S4 in FIG. 6), and the underwater robot 4 is then moved to engage the sling hook 31 of the hook device 6 with the underwater structure 3 to be slinged (S5 in FIG. 6: sling hook engaging step). After the underwater robot 4 releases its hold on the hook device 6 (S6 in FIG. 6: hold releasing step), the underwater robot 4 is retracted from the underwater structure 3 to be slinged (S7 in FIG. 6: retracting step). Thereafter, the sling rope 2 is wound up by a crane mounted on a work boat or the like to lift the sling hook 31, thereby floating the underwater structure 3 (S8 in FIG. 6: lifting step). This will be explained in detail below.

[0078] In the above-described slinging method, one end of the sling rope 2 is connected to the hook device 6 before the hook device 6 is dropped into water (S1 in FIG. 6). Specifically, one end 4a of the sling rope 2 (see FIGS. 5A and 5B) is connected to the sling hook 31 of the hook device 6 on board a work boat or the like.

[0079] Thereafter, the hook device 6, with one end 4a of the sling rope 2 connected, is dropped into the water from a vessel such as a work boat (S2 in FIG. 6). As described above, the buoyancy generated on the floating body 32 in the water (under the sea) is slightly smaller than the gravity acting on the hook device 6, so the hook device 6 sinks in the water (under the sea). The hook device 6 dropped into the water descends under its own weight and eventually hits the bottom 101 of the water. Due to the buoyancy generated on the floating body 32, the hook device 6 descends while maintaining a gentle speed.

[0080] The hook device 6 that has landed on the water bottom 101 assumes an overturned posture as shown in Figure 8. In the hook device 6, the sling hook 31 is positioned at the center of the width direction Y of the hollow box-shaped float 32, so as long as the water bottom 101 is generally flat even if there are some irregularities or a slight incline, the hook device 6 will assume the same overturned posture no matter which way in the width direction Y it falls after landing on the water bottom 101.

[0081] After the hook device 6 is dropped into the water, the underwater robot 4 is dropped into the water from a vessel such as a work boat. Prior to dropping the underwater robot 4, one end of a robot recovery rope is connected to the underwater robot 4. The underwater robot 4 may be dropped into the water before the hook device 6 is dropped into the water.

[0082] The underwater robot 4, once dropped into the water, is moved toward the hook device 6, which has landed on the bottom, by an operator operating the display operation unit 5. The underwater robot 4 moves underwater while maintaining a horizontal posture (see FIGS. 1 and 7). The underwater robot 4 then approaches the hook device 6 (see FIG. 7), and the movement (approach) of the underwater robot 4 is then stopped at an approach position (see FIG. 8) located to the side of the hook device 6, which is in an overturned posture, on the side of the engagement rod 33 and above the hook device 6. The orientation of the underwater robot 4 is then controlled by the operator, and as shown in FIG. 8, the underwater robot 4 is oriented so that the fore-and-aft directions FD, RD of the underwater robot 4 (i.e., the direction in which the rotation axis C extends) and the longitudinal direction X of the engagement rod 33 of the hook device 6, which is in an overturned posture, are parallel to each other.

[0083] When thrown into water, the posture of the hand 23 of the underwater robot 4 is in the release posture P2. Therefore, when the underwater robot 4 is positioned in the approach position (see Figure 8), the posture of the hand 23 of the underwater robot 4 is in the release posture P2. Then, by changing the posture of the hand 23 from the release posture P2 to the engagement posture P1, the engagement rod 33 of the hook device 6 engages with the multiple hook-shaped claws 25. As a result, the hook device 6 that has landed on the bottom is captured by the underwater robot 4 and held by the underwater robot 4 (S3 in Figure 6: hook device holding process).

[0084] Specifically, after the underwater robot 4 is positioned and oriented as shown in Figure 8, the operator rotates the hand 23 of the underwater robot 4. From a state in which the hand 23 is in the release position P2, the multiple hooked claws 25 of the hand 23 are rotated so that the tips 25b point downward, causing each hooked claw 25 to enter the gap between the rod portion 51 of the engagement rod 33 and the other surface 34b of the float 32 of the hook device 6. Then, as shown in Figure 9, each hooked claw 25 abuts against the rod portion 51, and the tips 25b of the hooked claws 25 of the rod portion 51 rest on the inner surfaces 25c of the hooked claws 25. From this state, by further rotating each hooked claw 25, the rod portion 51 moves relative to the inner surfaces 25c of the hooked claws 25 toward the base ends 25a, and fits into the fitting grooves 26 formed in the inner surfaces 25c of the hooked claws 25.

[0085] Then, as each of the hook-shaped claws 25 is further rotated from this state, the engaging rod 33 side of the hook device 6 is raised as shown in FIG. 10. Because the hook-shaped claws 25 are fitted into the engagement grooves 26, even if the tips 25b of the hook-shaped claws 25 are raised, the hook-shaped claws 25 do not move along the inner surface 25c. When each of the hook-shaped claws 25 is further rotated and the hand 23 reaches the engagement position P1 (the tips 25b of the hook-shaped claws 25 are at the height shown in FIG. 11), the rotation of each of the hook-shaped claws 25 is stopped. As a result, the engagement between the engagement rod 33 of the hook device 6 and the multiple hook-shaped claws 25 is maintained. This allows the hook device 6, which has landed on the bottom, to be captured by the underwater robot 4 and held by the underwater robot 4. Then, by keeping the hand 23 in the engagement position P1, the engagement between the hook-shaped claws 25 and the engagement rod 33 is maintained.

[0086] In this way, the underwater robot 4 holds (captures) the hook device 6 by engaging the engagement rod 33 with the hook-shaped claw 25. The hook device 6 can be held (captured) as long as the engagement rod 33 can be engaged with the hook-shaped claw 25. Therefore, the hook device 6 can be held (captured) well regardless of the posture of the hook device 6 placed underwater (descended on the water bottom 101).

[0087] 1, three of the four hooked claws 25 engage with the engagement rod 33. The length of the engagement rod 33 in the longitudinal direction X is set to be longer than the distance between both ends of three consecutive hooked claws 25 in the axial direction of the rotation shaft 22, but shorter than the distance between both ends of four consecutive hooked claws 25 in the axial direction. Therefore, the engagement rod 33 of the hook device 6 can engage with three hooked claws 25 simultaneously, but cannot engage with all four hooked claws 25 simultaneously.

[0088] Furthermore, the load capacity of each of the hook-shaped claws 25 of the hand 23 is determined so that the hand 23 can hold the hook device 6 even when only one hook-shaped claw 25 is engaged with the engagement rod 33. Therefore, the hook device 6 can be held by the hand 23 not only when three hook-shaped claws 25 are engaged with the engagement rod 33 at the same time, but also when two hook-shaped claws 25 are engaged with the engagement rod 33 at the same time or when only one hook-shaped claw 25 is engaged with the engagement rod 33.

[0089] After the underwater robot 4 has held (captured) the hook device 6, the operator operates the display operation unit 5 to move the underwater robot 4 toward the underwater structure 3 (S4 in Figure 6). When the underwater robot 4 leaves the water bottom 101, the hook device 6 is suspended from the underwater robot 4, as shown in Figure 11. As shown in Figure 1, even while holding the hook device 6, the underwater robot 4 moves underwater while maintaining a horizontal attitude.

[0090] When the hand 23 is in the engagement position P1, the opposing surface 24a of the regulating rod 24 faces laterally (to the left as viewed from the underwater robot 4) the rod portion 51 of the engaging rod 33. In this state, the opposing surface 24a of the regulating rod 24 and the rod portion 51 are close to each other.

[0091] After the underwater robot 4 approaches the underwater structure 3, the operator operates the display operation unit 5 to move the underwater robot 4 or change the posture of the underwater robot 4, as shown in Figure 12, so that the sling hook 31 of the hook device 6 held by the underwater robot 4 engages with the hook portion 61 of the underwater structure 3 to be sling-loaded (S5 in Figure 6: sling hook engagement process).

[0092] Specifically, as shown in FIG. 12, the tip attachment 43 of the sling hook 31 is inserted below the hook portion 61. The tip attachment 43 guides the hook portion 61 to a position facing the anti-detachment fitting 45. As shown in FIG. 12, the underwater robot 4 is moved backward in the RD direction while being maintained in a slightly tilted position (backward tilt position). As a result, the anti-detachment fitting 45 of the sling hook 31 is pressed against the hook portion 61, and the reaction force causes the tip portion 45b of the anti-detachment fitting 45 to be pushed open against the biasing force. An opening is then formed between the base end 41a and the tip end 41b of the sling hook 31. The hook portion 61 enters the sling hook 31 through this opening. After the hook portion 61 enters, the anti-detachment fitting 45 is biased to a closed position, closing the opening. As a result, the sling hook 31 of the hook device 6 engages with the hook portion 61 of the underwater structure 3 to be slinged, as shown in FIG. 13. As a result, the sling rope 2 is connected (hanged) to the underwater structure 3.

[0093] The tip attachment 43 extends so that the shortest distance between it and the one surface 34a increases toward the tip portion 43b, ensuring a wide entrance for the slinging hook 31. When the tip attachment 43 is inserted downward (i.e., when it enters the entrance of the slinging hook 31), the hook portion 61 is guided to a position facing the anti-detachment fitting 45. Therefore, the hook portion 61 and the anti-detachment fitting 45 can be easily positioned.

[0094] Furthermore, when the hook portion 61 is pushed in (see Figure 12), the tilted attitude (backward tilted attitude) of the underwater robot 4 needs to be controlled with high precision, but when positioning the hook portion 61 and the anti-detachment fitting 45, there is no need to control the tilted attitude of the underwater robot 4 with high precision. Therefore, the positioning of the hook portion 61 and the anti-detachment fitting 45 can be achieved with approximate attitude control.

[0095] Furthermore, because tip attachment 43 is made of an elastic material, even if tip attachment 43 collides with hook portion 61 or top surface 3a, the impact can be absorbed. Therefore, tip attachment 43 can be prevented from being bounced off due to a collision with hook portion 61 or top surface 3a, and tip attachment 43 can smoothly guide hook portion 61.

[0096] As described above, the operator can visually check the condition of the sling hook 31 while moving the underwater robot 4 to move or change the position of the sling hook 31, thereby engaging the sling hook 31 with the hook portion 61 of the underwater structure 3. This allows the sling hook 31 to smoothly engage with the underwater structure 3.

[0097] After the sling hook 31 engages with the underwater structure 3, the operator operates the display operation unit 5, causing the underwater robot 4 to rotate the hand 23 to disengage the engagement rod 33 from the hook-shaped claw 25 (S6 in Figure 6: retention release process).

[0098] Specifically, the hand 23 of the underwater robot 4 is rotated to change the position of the hand 23 from the engagement position P1 to the disengagement position P2 in the reverse order of the operations described using Figures 8 to 11. This disengages the engagement rod 33 from the hook-shaped claw 25, and the underwater robot 4 releases its hold on the hook device 6. Rotating the hand 23 releases the engagement between the engagement rod 33 and the hook-shaped claw 25, allowing the underwater robot 4 to smoothly release its hold on the hook device 6.

[0099] Thereafter, the operator operates the display operation unit 5 to cause the underwater robot 4 to retreat from the underwater structure 3 to which it is being sling-mounted (S7 in FIG. 6: retreat process), and to rise to near the water surface. The surfaced underwater robot 4 is lifted up and recovered by winding up the recovery rope. After the underwater robot 4 has retreated, tension is applied to the sling rope 2 by winding up the sling rope 2 using a crane mounted on a work boat or the like. This causes the hook device 6 engaged with the underwater structure 3 to assume the up-down position shown in FIG.

[0100] When the hook portion 61 of the underwater structure 3 is engaged and the hook device 6 is in an up-down position (the state shown in FIG. 13), one end 32a of the floating body 32 is positioned above the top surface 3a of the underwater structure 3 at a small distance. Also, in this state, the other surface 34b of the floating body 32 is positioned laterally inwardly at a small distance from the side wall of the groove 3b. Therefore, it is possible to prevent the floating body 32 from colliding with the underwater structure 3.

[0101] In addition, since the tip 31a of the sling hook 31 is retracted in the other direction X2 relative to the one end 32a of the floating body 32, when the floating body 32 assumes an up-and-down position, the one end 32a of the floating body 32 is retracted upward relative to the tip 31a of the sling hook 31. In this state, even if the hook device 6 vibrates up and down and collides with the underwater structure 3, the one end 32a of the floating body 32 is retracted, so that the floating body 32 can be more effectively prevented from colliding with the underwater structure 3. Therefore, damage to the floating body 32 and the underwater structure 3 can be more effectively suppressed or prevented.

[0102] Then, from this state, by further winding up the sling rope 2, the sling hook 31 is lifted and the underwater structure 3 is raised (S8 in FIG. 6: lifting process). Because the sling hook 31 is lifted after the underwater robot 4 has retreated, it is possible to avoid the underwater robot 4 interfering with the underwater structure 3 or the sling rope 2, which is in a tensioned state, during this lifting operation. This allows the sling hook 31 to be lifted smoothly.

[0103] As described above, according to this embodiment, slinging work is achieved by a series of operations: holding (capturing) the hook device 6, engaging the sling hook 31, and releasing the hook device 6. Specifically, the hook device 6 is held (captured) by the underwater robot 4 by rotating the hand 23 of the underwater robot 4 to engage the engagement rod 33 with the hook-shaped claw 25, so the hook device 6 can be held (captured) smoothly. In addition, the underwater robot 4 holding the hook device 6 is moved to engage the sling hook 31 of the hook device 6 with the underwater structure 3, so the sling hook 31 and the underwater structure 3 can be smoothly engaged, thereby smoothly connecting (slinging) the sling rope 2 to the underwater structure 3. In addition, the hook device 6 is released from its hold by the underwater robot 4 by rotating the hand 23 to disengage the engagement rod 33 from the hook-shaped claw 25, so the hook device 6 can be smoothly released from its hold by the underwater robot 4. Since each task can be performed smoothly, a series of slinging tasks using the underwater robot 4 can be smoothly realized.

[0104] Furthermore, the hand 23 is made up of multiple hook-shaped claws 25 aligned along the rotation axis C, and the underwater robot 4 is able to hold (capture) the hook device 6 by engaging this comb-shaped hand 23 with the engagement rod 33. The hand 23 can hold (capture) the underwater robot 4 as long as at least one of the multiple hook-shaped claws 25 is engaged with the engagement rod 33. Therefore, when the underwater robot 4 holds (captures) the hook device 6, the underwater robot 4 can hold (capture) the hook device 6 even if the underwater robot 4 is not positioned with high precision relative to the hook device 6. Therefore, when the underwater robot 4 holds (captures) the hook device 6, a high level of skill is not required to operate the display / operation unit 5. This allows even an operator with low skill to successfully hold (capture) the hook device 6 with the underwater robot 4.

[0105] Furthermore, by rotating the hand 23 of the underwater robot 4 to change the position of the hand 23 between the engagement position P1 and the disengagement position P2, it is possible to switch between engagement and disengagement with the engagement rod 33. Therefore, engagement / disengagement of the underwater robot 4 with the engagement rod 33 can be achieved with a simple configuration.

[0106] Furthermore, when the engagement rod 33 and the hook-shaped claw 25 are engaged with each other, the rod portion 51 of the engagement rod 33 is fitted into the fitting groove 26 formed on the inner surface 25c of the hook-shaped claw 25. This makes it possible to suppress or prevent the engagement rod 33 from shifting or moving relative to the hook-shaped claw 25 in this state. This makes it possible to suppress or prevent the engagement between the engagement rod 33 and the hook-shaped claw 25 from being disengaged when the engagement rod 33 and the hook-shaped claw 25 are engaged with each other.

[0107] Furthermore, the hook device 6 is equipped with an engagement rod 33 in addition to the float 32 and the sling hook 31. By engaging the engagement rod 33 with the underwater robot 4, the underwater robot 4 can smoothly hold (capture) the hook device 6.

[0108] In the hook device 6, the sling hook 31 is connected to one surface 34a of the float 32, and the rod portion 51 is connected to the other surface 34b of the float 32. Since the connection between the engaging rod 33 and the sling hook 31 is achieved via the float 32, the engaging rod 33 and the sling hook 31 can be integrated together regardless of the shape or dimensions of the engaging rod 33 and the sling hook 31.

[0109] Furthermore, since the sling hook 31 is positioned at the center of the width direction Y of the hollow box-shaped float 32, the hook devices 6 submerged in water will assume the same overturned posture no matter which way they fall in the width direction Y after hitting the bottom. In this overturned posture, the rod portion 51 of the engagement rod 33 will be aligned with the bottom 101 of the water. This allows the underwater robot 4 to smoothly hold (capture) the hook device 6 by rotating the hand 23 of the underwater robot 4.

[0110] Furthermore, the slinging hook 31 and the floating body 32 are connected to each other so that they can be separated from each other. It is conceivable that after the slinging hook 31 and the underwater structure 3 are connected, a large impact or the like is applied to the hook device 6, causing the floating body 32 to hit the underwater structure 3. If a large impact or the like is applied to the hook device 6 due to contact with the floating body 32, there is a risk that the floating body 32 will damage the underwater structure 3. Because the slinging hook 31 and the floating body 32 are connected to each other so that they can be separated from each other, the floating body 32 will separate from the slinging hook 31 when a large impact or the like is applied to the hook device 6. This makes it possible to suppress or prevent damage to the floating body 32 and the underwater structure 3.

[0111] Although one embodiment of the present invention has been described above, the present invention can be embodied in other forms. For example, a float rope other than the sling rope 2 may be connected to the float 32. In this case, even if the float 32 separates from the sling hook 31, the float 32 can be lifted up via the sling rope 2, thereby allowing the float 32 to be recovered. Note that the means for connecting the float 32 to the sling hook 31 is not limited to tape, and other means may be used. Also, while the number of segmented boxes 35 included in the hollow box 34 of the float 32 is described as two, the number may be three or more. Also, the hollow box 34 may include only one segmented box 35, i.e., the hollow box 34 may not include multiple segmented boxes 35.

[0112] Furthermore, in the sling hook 31, the tip attachment 43 may be attached to the tip portion 41b of the hook main body 41 by other methods than a fixing device. As shown in FIG. 14, the base end 43a of the tip attachment 43 may be tubular (cylindrical). The tubular base end 43a is fitted and fixed to the tip portion 41b of the hook main body 41. When attaching the tip attachment 43 to the tip portion 41b of the hook main body 41, the base end 43a of the tip attachment 43, which is made of an elastic material (e.g., rubber), is fitted to the tip portion 41b in an expanded state. At this time, when the expanded state of the base end 43a is released, the elastically contracting base end 43a is attached to the tip portion 41b of the hook main body 41. Then, the binding force of the elastic contraction allows the tip attachment 43 to be attached to the tip portion 41b without using a fixing device such as a bolt.

[0113] Furthermore, tip attachment 43 may be formed using a metal material such as steel instead of an elastic material. In this case, tip attachment 43 may be fixed to tip portion 41b of hook main body 41 using a fastener such as a bolt as described above. In this case, tip attachment 43 may also be fixed to tip portion 41b of hook main body 41 by other methods such as welding.

[0114] Furthermore, without employing a detachable attachment structure, the tip portion 41b of the hook main body 41 may be extended to have a configuration similar to that of the tip attachment 43.

[0115] Furthermore, the rotation unit 21 of the operating device 12 of the underwater robot 4 may be configured with a rotation unit other than an electric motor, for example, a cylinder. Furthermore, it is not necessary for the fitting groove 26 to be formed on the inner surface 25c of all of the hooked claws 25 included in the hand 23, as long as the fitting groove 26 is formed on at least two of the hooked claws 25. Furthermore, the extension direction of the rotation shaft 22 of the operating device 12 of the underwater robot 4 (the extension direction of the rotation axis C) does not need to be along the fore-and-aft directions FD, RD of the underwater robot 4, and may be along the left-and-right direction of the underwater robot 4, for example.

[0116] 3A, 3B, and 11, the engagement posture P1 of the hand 23 may be the posture shown in Fig. 10 if good engagement with the engagement rod 33 can be maintained. Similarly, the release posture P2 of the hand 23 may be the posture shown in Fig. 8, but may be the posture shown in Fig. 9 if the engagement rod 33 can be smoothly released from the hand 23.

[0117] Furthermore, the underwater robot 4 and the display operation unit 5 may be able to communicate wirelessly rather than by wire. Wireless communication between the underwater robot 4 and the display operation unit 5 can be achieved by a known configuration.

[0118] Furthermore, the underwater structure 3 to be slinged may have other shapes. The groove 3b may not be formed on the top surface 3a of the underwater structure 3, and the inverted U-shaped hook portion 61 may be arranged exposed on the top surface 3a of the underwater structure 3. In this case, both ends of the hook portion 61 may be fixed to the top surface 3a of the underwater structure 3. Furthermore, the underwater structure 3 may have other shapes than a rectangular parallelepiped.

[0119] The present invention is not limited to the contents of the above-described embodiment, and various modifications are possible within the scope of the claims. [Explanation of symbols]

[0120] 2: sling rope, 3: underwater structure, 4: underwater robot, 4a: one end, 5: display operation unit, 6: hook device, 11: robot body, 12: operation device, 21: rotation unit, 23: hand, 25: hook-shaped claw, 25b: tip, 25c: inner surface, 26: fitting groove, 31: sling hook, 31a: tip, 32: floating body, 32a: one end, 33: engaging rod, 34a: one surface, 43: tip attachment (tip tool), X: longitudinal direction

Claims

1. A slinging method for slinging a sling rope to an underwater structure disposed underwater, comprising: a hook device holding step in which a hook device having a sling hook and an engagement rod and connected to the sling rope and placed underwater is held by the underwater robot by rotating a hand of the underwater robot, the hand having a plurality of hook-shaped claws spaced apart along a rotation axis, about the rotation axis to place the hand in an engagement position in which the engagement rod and the hook-shaped claws can engage with each other; a sling hook engaging step of moving the underwater robot holding the hook device to engage the sling hook with the underwater structure, thereby slinging the sling rope to the underwater structure; and a release step of releasing the hold of the hook device by the underwater robot after the sling hook engages with the underwater structure by rotating the hand about the rotation axis to place the hand in a release position in which the engagement rod can be released from the hook-shaped claw.

2. a retraction step of retracting the underwater robot from the hook device after releasing the hold of the hook device; 2. The slinging method according to claim 1, further comprising a lifting step of lifting the underwater structure by lifting the sling hook via the sling rope after the underwater robot has retreated.

3. An operating device mounted on an underwater robot, a hand that is rotatable about a predetermined rotation axis and has a plurality of hook-shaped claws spaced apart along the rotation axis; a rotation unit that rotates the hand around the rotation axis, An operating device in which the rotating unit rotates the hand around the rotation axis, causing the hand to change position between an engagement position in which the engagement rod and the hooked claw can engage with each other, and a disengagement position in which the engagement rod can disengage from the hooked claw.

4. The operating device according to claim 3 , wherein an inner surface of at least two of the hook-shaped claws included in the hand is formed with a fitting groove into which the engagement rod fits.

5. A hook device for attaching a sling rope to an underwater structure located underwater, Floating body and a sling hook coupled to one side of the floating body, the sling hook being connected to the sling rope; a hook device coupled to the other side of the floating body opposite the one side, and including an engagement rod for engaging with an underwater robot.

6. The floating body is a hollow box-like body, The sling hook is coupled to one surface of the float, The hook device according to claim 5 , wherein the engagement rod is coupled to an opposite surface of the floating body opposite to the one surface.

7. The sling hook includes a hook-shaped hook body and a tip tool that is detachable from a tip end of the hook body, 7. The hook device according to claim 6, wherein, in a state in which the tip tool is attached to the tip portion of the hook body, the tip tool extends so that the shortest distance between the tip tool and the one surface increases toward the tip of the tip tool.

8. 8. The hook device according to claim 7, wherein the tip tool is made of an elastic body that is elastically deformable.

9. The floating body has a longitudinal axis, A hook device according to any one of claims 5 to 8, wherein the tip of the sling hook protrudes toward one end of the float in the longitudinal direction.

10. A hook device according to any one of claims 5 to 9, wherein the sling hook and the float are detachably connected to each other.

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