Spreader relocation device, crane, and spreader relocation method

Abstract

To provide a spreader relocation device, a crane, and a spreader relocation method that enable efficient relocation of an upper spreader when changing the specifications of a crane.SOLUTION: A spreader relocation device (70) comprises guide rails (71R, 71L) that guide an upper spreader (40) between first mounting portions (61R, 61L) and second mounting portions (62R, 62L) for detachably mounting mounting portions (41R, 41L) of the upper spreader (40). The upper spreader (40) has guided portions (42R, 42L). The guide rails (71R, 71L) are shaped such that, when a boom (14) is in a lowered state, the guided portions (42R, 42L) move along the guide rails (71R, 71L) and thereby climb over the first mounting portions (61R, 61L).SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present disclosure relates to a technique for changing the attachment position of an upper spreader in a crane.

Background Art

[0002] Patent Document 1 discloses a tower crane configured to move an upper spreader for boom hoisting and lowering between a position on the boom base end side along the boom upper surface and a position on the tip end side to be connected or separated from a strut guy line when assembling and disassembling the tower crane. In this tower crane, a support leg guide member for guiding the movement of the support leg is provided on the boom upper surface.

[0003] Patent Document 2 discloses a connection mechanism provided with a guide rail capable of guiding an upper spreader to a connection position with a lower spreader by winding a hoisting rope by a hoisting winch.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, there are cranes that can, for example, change from a crane specification to a tower specification and from a tower specification to a crane specification. In the crane specification, a boom is supported on the upper slewing body so as to be able to be hoisted and lowered, and a jib is not attached to the tip of the boom. In the tower specification, a boom is supported on the upper slewing body so as to be able to be hoisted and lowered, and a jib is attached to the tip of the boom. In the above crane that can change the specification, the following problems occur.

[0006] The work of changing the specifications of the crane includes the work of connecting the guy line for connecting the guy line to the upper spreader. This guy line connection work is performed with the upper spreader temporarily attached to an attachment part such as a bracket protruding from the boom. In the crane specifications and tower specifications, since the angle of the boom (the elevation angle with respect to the ground) during the operation of lifting the suspended load is different, the length of the guy line connecting the upper spreader and the tip of the boom is different. Specifically, since the angle of the boom in the tower specification is larger than the angle of the boom in the crane specification, the guy line in the tower specification is shorter than the guy line in the crane specification. Therefore, the crane whose specifications can be changed as described above includes an attachment part (attachment part for crane specifications) protruding from the boom at a position suitable for the length of the guy line in the crane specifications, and an attachment part (attachment part for tower specifications) protruding from the boom at a position suitable for the length of the guy line in the tower specifications. The attachment part for tower specifications is located at a position separated from the attachment part for crane specifications in the longitudinal direction of the boom.

[0007] In the specification change of the crane as described above, it is necessary to perform a relocation work of moving the upper spreader from one of the attachment parts for crane specifications and the attachment parts for tower specifications to the other and attaching the upper spreader to the attachment part at the moving destination. It is desired to improve the workability of this relocation work.

Means for Solving the Problem

[0008] An object of the present disclosure is to provide a spreader relocation device, a crane, and a spreader relocation method that can efficiently perform the relocation work of the upper spreader in the specification change of the crane.

[0009] The spreader transfer device according to the first aspect of the present disclosure is a device for a crane, and the crane includes a boom, a lower spreader and an upper spreader for raising and lowering the boom, a first protrusion, and a second protrusion. The first protrusion has a first attachment portion for detachably attaching the attached portion of the upper spreader and protrudes from the boom. The second protrusion has a second attachment portion for detachably attaching the attached portion of the upper spreader and protrudes from the boom at a position away from the first protrusion in the longitudinal direction of the boom. The spreader transfer device includes a guide rail for guiding the upper spreader between the first attachment portion and the second attachment portion. The upper spreader has a guided portion, and the guide rail has a shape such that the guided portion can move along the guide rail and cross over the first attachment portion when the boom is in a collapsed state.

[0010] In this first aspect, the guided portion of the upper spreader can cross over the first attachment portion by moving along the guide rail. Therefore, in the spreader transfer operation, the upper spreader can be transferred while avoiding contact between the guided portion and the first attachment portion of the first protrusion simply by moving the guided portion of the upper spreader along the guide rail. Thereby, the workability of the spreader transfer operation is improved.

[0011] The crane according to the second aspect includes the boom, the lower spreader, the upper spreader, the first protrusion, the second protrusion, and the spreader transfer device according to the first aspect. In the crane according to this second aspect, the workability of the spreader transfer operation is improved.

[0012] The crane according to the third aspect preferably further has the following configuration in the crane according to the second aspect. That is, in the crane according to the third aspect, the spreader transfer device includes a rail support portion that supports the guide rail, and the rail support portion is preferably detachably supported by at least one of the boom, the first protrusion, and the second protrusion. In this third aspect, after the completion of the spreader transfer operation, the spreader transfer device can be removed from the protrusion (the mounted portion). Therefore, the spreader transfer device does not interfere with other operations performed before the spreader transfer operation and after the spreader transfer operation.

[0013] The crane according to the fourth aspect preferably further has the following configuration in the crane according to the second or third aspect. That is, in the crane according to the fourth aspect, the spreader transfer device includes a rail support portion that supports the guide rail, and the rail support portion is preferably supported by at least one of the first protrusion and the second protrusion. In this fourth aspect, the spreader transfer device can be attached to the first protrusion and the second protrusion without modifying the boom.

[0014] The crane according to the fifth aspect preferably further has the following configuration in the crane according to any one of the second to fourth aspects. That is, in the crane according to the fifth aspect, the spreader transfer device preferably includes an upper guide rail that is disposed at an interval above the guide rail and extends along the guide rail. In this fifth aspect, in the spreader transfer operation performed with the boom in a collapsed state, even when an upward external force acts on the upper spreader when the guided portion of the upper spreader moves along the guide rail, since the upper guide rail restricts the upward movement of the upper spreader, the spreader transfer operation can be performed while maintaining the state where the guided portion of the upper spreader is close to or in contact with the guide rail. Examples of the external force include, for example, the force acting on the upper spreader from the boom hoisting rope and the force acting on the upper spreader from the boom guy line.

[0015] The crane according to the sixth aspect preferably further has the following configuration in the crane according to the fifth aspect. That is, in the crane according to the sixth aspect, at least one of both ends of the upper guide rail preferably has a shape extending obliquely upward. In this sixth aspect, the operation of inserting the guided portion of the upper spreader between the guide rail and the upper guide rail can be efficiently performed.

[0016] The crane according to the seventh aspect preferably further includes the following configuration in the crane according to any one of the second to sixth aspects. That is, in the crane according to the seventh aspect, the boom includes a first boom member and a second boom member connected to the first boom member. The first protrusion is supported by the first boom member, and the second protrusion is supported by the second boom member. The spreader transfer device is configured to be displaceable between a guide position and a retracted position while being supported by at least one of the boom, the first protrusion, and the second protrusion. The guide position is a position for guiding the upper spreader between the first attachment portion and the second attachment portion, and the retracted position is preferably a position farther from the connection portion between the first boom member and the second boom member than the guide position. In this seventh aspect, when the spreader transfer operation is performed, the spreader transfer device is arranged at the guide position, and after the completion of the spreader transfer operation, the spreader transfer device can be arranged at the retracted position. Thereby, for example, in the connection operation of connecting the first boom member and the second boom member, the spreader transfer device does not get in the way. Also, when the crane is disassembled into a plurality of sections and each section is transported using a transporter such as a trailer, the spreader transfer device is supported by at least one of the boom, the first protrusion, and the second protrusion. That is, in this seventh aspect, it is not necessary to remove the spreader transfer device from at least one of the boom, the first protrusion, and the second protrusion in either the spreader transfer operation or the transportation. This can save the trouble of managing (managing parts) the spreader transfer device during transportation.

[0017] In addition, when the spreader transfer device is disposed at the guide position and the upper end of the spreader transfer device is disposed above the upper ends of the first protrusion and the second protrusion, it is preferable that the upper end of the spreader transfer device be disposed below the upper ends of the first protrusion and the second protrusion by disposing the spreader transfer device at the retracted position. In this case, it becomes easier to avoid the height of the section including the spreader transfer device exceeding the height limit during transportation.

[0018] The crane according to the eighth aspect preferably further has the following configuration in the crane according to any one of the second to seventh aspects. That is, in the crane according to the eighth aspect, the width direction of the boom is the left-right direction, the guide rail is a right guide rail, the guided portion is a right guided portion, the upper spreader has a left guided portion, and the spreader transfer device is a left guide rail disposed at a distance to the left of the right guide rail and guiding the upper spreader between the first attachment portion and the second attachment portion. The left guide rail preferably has a shape that allows the left guided portion to cross over the first attachment portion as the left guided portion moves along the left guide rail when the boom is in the collapsed state. In this eighth aspect, since the spreader transfer device includes a right guide rail and a left guide rail, the right guided portion and the left guided portion of the upper spreader can move from one of the first attachment portion and the second attachment portion to the other in a more stable posture along the right guide rail and the left guide rail.

[0019] The crane according to the ninth aspect preferably further includes the following configuration in the crane according to the eighth aspect. That is, in the crane according to the ninth aspect, the spreader transfer device preferably includes a right rail support portion that supports the right guide rail, a left rail support portion that supports the left guide rail, a right inclined wall that extends obliquely upward to the right above the right rail support portion, and a left inclined wall that extends obliquely upward to the left above the left rail support portion. In this ninth aspect, since the right inclined wall extends obliquely upward to the right and the left inclined wall extends obliquely upward to the left, when the right guided portion of the upper spreader moves along the right guide rail and the left guided portion moves along the left guide rail during the spreader transfer operation, an upward external force acts on the upper spreader. Even when the upper spreader moves upward away from the right guide rail and the left guide rail, it is easy to return the guided portion of the upper spreader to the right guide rail and the left guide rail. Specifically, when reducing the action of the external force to lower the upper spreader, the right inclined wall and the left inclined wall can guide the guided portion of the upper spreader to the right guide rail and the left guide rail even if the upper spreader is somewhat biased to either the left or the right.

[0020] The crane according to the tenth aspect preferably further includes the following configuration in the crane according to any one of the second to ninth aspects. That is, the crane according to the tenth aspect includes a guide member for guiding the upper spreader that descends by increasing the distance between the lower spreader and the upper spreader in a state where the boom is laid down to the first mounting portion. The guided portion is configured to move along the guide rail when the upper spreader is transferred using the spreader transfer device, and is preferably configured to move along the guide member when the upper spreader is guided using the guide member. In this tenth aspect, the guided portion can be used for both the transfer operation of the upper spreader using the spreader transfer device and the guiding operation of the upper spreader using the guide portion.

[0021] The crane according to the 11th aspect preferably further includes the following configuration in the crane according to any one of the 2nd to 10th aspects. That is, the crane according to the 11th aspect preferably includes a traction device for moving the upper spreader along the guide rail from the first attachment portion toward the second attachment portion. In this 11th aspect, since the traction device assists the spreader relocation work, the workability of the spreader relocation work is further improved.

[0022] The crane according to the 12th aspect preferably further includes the following configuration in the crane according to the 11th aspect. That is, in the crane according to the 12th aspect, the traction device is preferably a chain block with a torque control function. In this 12th aspect, when the traction device is a chain block, excessive tension does not act on the upper spreader, so that it is possible to prevent excessive load from being applied to the components related to the relocation work, such as the upper spreader and the spreader relocation device.

[0023] The spreader relocation method according to the 13th aspect is a spreader relocation method using the crane according to any one of the 2nd to 12th aspects, and includes moving the upper spreader along the guide rail from one of the first attachment portion and the second attachment portion to the other. In this 13th aspect, the guided portion of the upper spreader can cross the first attachment portion by moving the guided portion of the upper spreader along the guide rail. Therefore, in the spreader relocation work, the upper spreader can be relocated while avoiding contact between the guided portion and the first attachment portion of the first protrusion by simply moving the guided portion of the upper spreader along the guide rail. Thereby, the workability of the spreader relocation work is improved.

Advantages of the Invention

[0024] According to the present disclosure, there are provided a spreader relocation device, a crane, and a spreader relocation method capable of efficiently performing the relocation work of the upper spreader in the specification change of the crane.

Brief Description of the Drawings

[0025]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Modes for Carrying Out the Invention

[0026] Embodiments of the present disclosure will be described with reference to the drawings. In the drawings, the directions of "left", "right", "front", and "rear" are shown. The front-rear direction is the horizontal direction along the direction in which the boom extends when the boom is in a collapsed state, and the left-right direction is the horizontal direction orthogonal to the front-rear direction.

[0027] FIG. 1 is a side view showing an example of a tower-type crane 10. The tower-type crane 10 includes a lower traveling body 11, an upper slewing body 12, a boom 14, and a jib 15.

[0028] The lower traveling body 11 can travel on a traveling surface such as the ground. The lower traveling body 11 includes, for example, a crawler-type traveling device. The lower traveling body 11 may include a traveling device other than the crawler type, for example, a traveling device using wheels or the like. Further, the crane according to the present disclosure may be a stationary crane that does not include a traveling device.

[0029] The upper slewing body 12 is supported by the lower traveling body 11 so as to be rotatable about a slewing center axis extending in the vertical direction. The upper slewing body 12 includes a slewing frame supported by the lower traveling body 11 and a driver's cab 13 supported by the slewing frame. The driver's cab 13 is disposed at the front portion of the slewing frame and can be boarded by an operator of the crane 10.

[0030] The boom 14 is rotatably supported in the raising and lowering direction by a support member (not shown) disposed at the front end portion of the upper slewing body 12. The boom 14 may include a plurality of boom members. In this case, the boom 14 is configured by connecting a plurality of boom members to each other along the longitudinal direction.

[0031] The plurality of boom members may include a lower boom member 14A and an upper boom member 14C. The plurality of boom members may further include at least one intermediate boom member 14B disposed between the lower boom member 14A and the upper boom member 14C. The lower end of the lower boom member 14A is rotatably supported by the upper swing body 12. The upper boom member 14C constitutes the upper part of the boom 14. The lower boom member 14A is an example of a first boom member, and the intermediate boom member 14B is an example of a second boom member.

[0032] The boom 14 may be a boom having a lattice structure as shown in FIGS. 2 and 3, for example. In this case, the boom 14 may include a plurality of main pipes 141, a plurality of inclined pipes 142, and a plurality of connectors 143. The plurality of main pipes 141 are arranged at positions corresponding to the four vertices of a quadrilateral (for example, a square) when viewed in the longitudinal direction of the boom 14. Each of the plurality of inclined pipes 142 connects two adjacent main pipes 141. For example, the main pipe 141 of the lower boom member 14A and the main pipe 141 of the intermediate boom member 14B are detachably connected by a connector 143.

[0033] The jib 15 is supported at the tip of the boom 14 (that is, the tip of the upper boom member 14C) so as to be able to rise and fall. The jib 15 may include a plurality of jib members. In this case, the jib 15 is configured by connecting a plurality of jib members to each other along the longitudinal direction. The jib 15 may be a jib having a lattice structure.

[0034] The crane 10 includes a boom hoist winch 16, a boom hoist rope 21, a lower spreader 17, an upper spreader 40, a boom guy line 19, and a gantry 20.

[0035] The boom hoist rope 21 is a wire rope for raising and lowering the boom 14. The boom hoist winch 16 winds up and pays out the boom hoist rope 21.

[0036] The gantry 20 is supported by the upper slewing body 12 behind the boom 14 and is arranged in a posture of standing upright upward. The gantry 20 functions as a support column in the hoisting operation of the boom 14. The gantry 20 supports the boom 14 via the boom guy line 19, the lower spreader 17, and the upper spreader 40.

[0037] The lower spreader 17 may be connected to the tip (upper end) of the gantry 20. Each of the lower spreader 17 and the upper spreader 40 has a plurality of sheaves. The plurality of sheaves may be arranged, for example, in the width direction (left - right direction). The boom hoisting rope 21 is hung on a guide sheave arranged at the tip of the gantry 20 and then wound around the plurality of sheaves of the lower spreader 17 and the plurality of sheaves of the upper spreader 40. The end of the boom hoisting rope 21 is fixed to a predetermined part (for example, the gantry 20, the lower spreader 17, or the upper spreader 40).

[0038] One end of the boom guy line 19 is connected to the upper spreader 40, and the other end of the boom guy line 19 is connected to the tip of the boom 14. When the boom hoisting winch 16 winds or pays out the boom hoisting rope 21, the distance between the lower spreader 17 and the upper spreader 40 changes, whereby the boom 14 hoists with respect to the upper slewing body 12.

[0039] The crane 10 includes a strut 22, a strut guy line 23, a jib guy line 24, a jib hoisting winch 25, a jib hoisting rope 27, a lower spreader 29 for jib hoisting, and an upper spreader 30 for jib hoisting.

[0040] The strut 22 includes a front strut 22A and a rear strut 22B. The strut 22 is rotatably supported at the tip of the boom 14 (for example, the tower cap). One end of the jib guy line 24 is connected to the tip of the front strut 22A, and the other end of the jib guy line 24 is connected to the tip of the jib 15.

[0041] The jib hoisting rope 27 is a wire rope for hoisting the jib 15. The jib hoisting winch 25 winds and unwinds the jib hoisting rope 27. The jib hoisting rope 27 is looped between the lower spreader 29 for jib hoisting and the upper spreader 30 for jib hoisting. One end of the strut guy line 23 is connected to the tip of the upper spreader 30 for jib hoisting, and the other end of the strut guy line 23 is connected to the tip of the rear strut 22B.

[0042] The crane 10 includes a main hoist winch 26, a main hoist rope 31, and a main hook 32. The main hoist rope 31 is a wire rope connected to the main hook 32. The main hoist winch 26 winds and unwinds the main hoist rope 31.

[0043] The main hoist rope 31 extends from the main hoist winch 26 along the boom 14 to the tip of the boom 14, extends along the jib 15 to the tip of the jib 15 via a sheave disposed at the tip of the boom 14, extends downward from the tip of the jib 15, is wound around the sheave of the main hook 32, and is fixed to the tip of the jib 15 or the main hook 32. When the main hoist winch 26 winds or unwinds the main hoist rope 31, the main hook 32 moves up and down.

[0044] The boom hoisting winch 16, the jib hoisting winch 25, and the main hoist winch 26 are supported by the upper slewing body 12, but at least one of these winches may be supported by the boom 14, for example. Each of these winches may be driven by a winch motor (not shown), for example. The winch motor may be a hydraulic motor that operates by being supplied with hydraulic oil from a hydraulic pump (not shown), or an electric motor that operates with electric power.

[0045] The crane 10 may be provided with a backstop 33. The backstop 33 can support the boom 14 from behind when the boom 14 stands upright with respect to the upper slewing body 12. The backstop 33 may be arranged, for example, between the tip of the gantry 20 and the tip of the lower boom member 14A of the boom 14.

[0046] Next, the crane specifications will be described. Although illustration is omitted, the crane 10 of the crane specification is different from the tower-type crane 10 in that it does not include the jib 15 in the tower-type crane 10 and does not include parts that are unnecessary in the crane specification among the parts related to the jib 15. Other configurations of the crane 10 of the crane specification are substantially the same as those of the tower-type crane 10.

[0047] The crane 10 of the crane specification may include a lower traveling body 11, an upper slewing body 12, a boom 14, a boom hoist winch 16, a boom hoist rope 21, a lower spreader 17, an upper spreader 40, a boom guy line 19, a gantry 20, a main hoist winch 26, a main hoist rope 31, and a main hook 32. Since these parts in the crane 10 of the crane specification are the same as the parts of the tower-type crane 10 described above, the description will be omitted.

[0048] In the crane 10 of the crane specification, the main hoist rope 31 extends from the main hoist winch 26 along the boom 14 to the tip of the boom 14, extends downward from the tip of the boom 14, is wound around the sheave of the main hook 32, and is fixed to the tip of the boom 14 or the main hook 32. When the main hoist winch 26 winds in or pays out the main hoist rope 31, the main hook 32 moves up and down.

[0049] The crane 10 according to this embodiment can change from a crane specification to a tower specification and from a tower specification to a crane specification. In the change from the tower specification to the crane specification, the jib 15 is removed from the crane 10 shown in FIG. 1, and among the parts related to the jib 15, the parts unnecessary in the crane specification (for example, parts such as the strut 22 and the jib guy line 24) are removed.

[0050] In the crane specification and the tower specification, since the angle of the boom 14 (the undulation angle with respect to the ground) during the operation of lifting the suspended load is different, the length of the boom guy line 19 that connects the upper spreader 40 and the tip of the boom is different. The angle of the boom in the tower specification is larger than the angle of the boom in the crane specification. Specifically, in the tower specification, the undulation angle of the boom 14 with respect to the ground is set to about 90 degrees, for example, and in the crane specification, the undulation angle of the boom 14 with respect to the ground is set to about 80 degrees, for example. Therefore, the boom guy line 19 in the tower specification is shorter than the boom guy line 19 in the crane specification.

[0051] The work of changing the specification of the crane 10 includes the guy line connection work for connecting the boom guy line 19 to the upper spreader 40. This guy line connection work is performed in a state where the upper spreader 40 is temporarily attached to an attachment part such as a bracket protruding from the boom 14.

[0052] FIG. 2 is a side view showing the crane 10 in the work of changing the specification. As shown in FIGS. 2 to 5, the crane 10 according to the embodiment includes a boom 14, a lower spreader 17 and an upper spreader 40 for undulating the boom 14, a first protruding portion to which the upper spreader 40 is attached in the crane specification, a second protruding portion to which the upper spreader 40 is attached in the tower specification, and a spreader transfer device 70 according to the embodiment.

[0053] In this embodiment, the first protruding portion includes a first right protruding portion 51R and a first left protruding portion 51L, and the second protruding portion includes a second right protruding portion 52R and a second left protruding portion 52L. The first right protruding portion 51R and the first left protruding portion 51L are arranged at positions spaced apart in the left-right direction and facing each other in the left-right direction. The second right protruding portion 52R and the second left protruding portion 52L are arranged at positions spaced apart in the left-right direction and facing each other in the left-right direction.

[0054] The first right protruding portion 51R has a shape that protrudes upward from the right side portion of the boom 14 in a state where the boom 14 is laid down. The first left protruding portion 51L has a shape that protrudes upward from the left side portion of the boom 14 in a state where the boom 14 is laid down.

[0055] The second right protruding portion 52R has a shape that protrudes upward from the right side portion of the boom 14 in a state where the boom 14 is laid down. The second right protruding portion 52R is arranged at a position separated from the first right protruding portion 51R in the longitudinal direction of the boom 14.

[0056] Specifically, the second right protruding portion 52R for the tower specification is arranged at a position between the first right protruding portion 51R for the crane specification and the tip of the boom 14. The first right protruding portion 51R is a plate-like member (for example, a bracket) that protrudes upward from the main pipe 141 located at the upper right in the laid-down boom 14. Similarly, the second right protruding portion 52R is a plate-like member (for example, a bracket) that protrudes upward from the main pipe 141 located at the upper right in the laid-down boom 14.

[0057] The second left protruding portion 52L has a shape that protrudes upward from the left side portion of the boom 14 in a state where the boom 14 is laid down. The second left protruding portion 52L is arranged at a position separated from the first left protruding portion 51L in the longitudinal direction of the boom 14.

[0058] Specifically, the second left protrusion 52L for the tower specification is disposed at a position between the first left protrusion 51L for the crane specification and the tip of the boom 14. The first left protrusion 51L is a plate-like member (e.g., a bracket) that protrudes upward from the main pipe 141 located in the upper left in the boom 14 in the collapsed state. Similarly, the second left protrusion 52L is a plate-like member (e.g., a bracket) that protrudes upward from the main pipe 141 located in the upper left in the boom 14 in the collapsed state.

[0059] The first right protrusion 51R has a first right attachment portion 61R for detachably attaching a later-described right attachment portion 41R in the upper spreader 40, and the first left protrusion 51L has a first left attachment portion 61L for detachably attaching a later-described left attachment portion 41L in the upper spreader 40. Each of the first right attachment portion 61R and the first left attachment portion 61L is formed at a position suitable for the length of the boom guy line 19 in the crane specification. In the present embodiment, as shown in FIGS. 3 to 5, each of the first right attachment portion 61R and the first left attachment portion 61L includes an insertion hole for inserting an insertion member (not shown) such as a pin. The first right attachment portion 61R and the first left attachment portion 61L are examples of the first attachment portion.

[0060] The second right protrusion 52R has a second right attachment portion 62R for detachably attaching the right attachment portion 41R in the upper spreader 40, and the second left protrusion 52L has a second left attachment portion 62L for detachably attaching the left attachment portion 41L in the upper spreader 40. Each of the second right attachment portion 62R and the second left attachment portion 62L is formed at a position suitable for the length of the guy line in the tower specification. In the present embodiment, as shown in FIGS. 3 to 5, each of the second right attachment portion 62R and the second left attachment portion 62L includes an insertion hole for inserting an insertion member (not shown) such as a pin. The second right attachment portion 62R and the second left attachment portion 62L are examples of the second attachment portion.

[0061] As shown in FIGS. 6, 7, and 13, the upper spreader 40 has at least one mounting portion, at least one guiding portion, at least one rope mounting portion, a plurality of sheaves 44, and a spreader body 45. The spreader body 45 has an upper plate, a lower plate, a right plate, and a left plate, and these plates define an internal space for accommodating the plurality of sheaves 44. The front and rear portions of the spreader body 45 may each be open. The plurality of sheaves 44 are rotatably supported by the spreader body 45.

[0062] In the present embodiment, the at least one mounting portion includes a right mounting portion 41R and a left mounting portion 41L. The at least one guiding portion includes a right guiding portion 42R and a left guiding portion 42L. The at least one rope mounting portion includes a right rope mounting portion 43R and a left rope mounting portion 43L.

[0063] In the upper spreader 40, the right mounting portion 41R is a portion to be attached to the first right mounting portion 61R or the second right mounting portion 62R, and the left mounting portion 41L is a portion to be attached to the first left mounting portion 61L or the second left mounting portion 62L. The right mounting portion 41R may be formed on the right plate of the spreader body 45 or may be a member supported by the spreader body 45 (e.g., the right plate). The left mounting portion 41L may be formed on the left plate of the spreader body 45 or may be a member supported by the spreader body 45 (e.g., the left plate). The right mounting portion 41R may be a portion including the front end portion of the right plate of the spreader body 45, and the left mounting portion 41L may be a portion including the front end portion of the left plate of the spreader body 45.

[0064] In this embodiment, as shown in FIGS. 6, 7, and 13, each of the right attachment portion 41R and the left attachment portion 41L includes an insertion hole for inserting the insertion member. In this case, as shown in the upper diagram (A) of FIG. 6, the insertion member is inserted into these insertion holes in a state where the insertion holes of the right attachment portion 41R of the upper spreader 40 and the insertion holes of the first right attachment portion 61R are aligned, and the insertion member is inserted into these insertion holes in a state where the insertion holes of the left attachment portion 41L of the upper spreader 40 and the insertion holes of the first left attachment portion 61L are aligned. Thus, the right attachment portion 41R and the left attachment portion 41L are attached to the first right attachment portion 61R and the first left attachment portion 61L. Similarly, as shown in the lower diagram (C) of FIG. 6, the insertion member is inserted into these insertion holes in a state where the insertion holes of the right attachment portion 41R of the upper spreader 40 and the insertion holes of the second right attachment portion 62R are aligned, and the insertion member is inserted into these insertion holes in a state where the insertion holes of the left attachment portion 41L of the upper spreader 40 and the insertion holes of the second left attachment portion 62L are aligned. Thus, the right attachment portion 41R and the left attachment portion 41L are attached to the second right attachment portion 62R and the second left attachment portion 62L.

[0065] In the upper spreader 40, the right guide portion 42R is a portion guided by a later-described right guide rail 71R in the spreader transfer device 70, and the left guide portion 42L is a portion guided by a later-described left guide rail 71L in the spreader transfer device 70. The right guide portion 42R may be supported by the right plate of the spreader body 45, and the left guide portion 42L may be supported by the left plate of the spreader body 45. Specifically, for example, the right guide portion 42R may be supported by the right plate of the spreader body 45 behind the right attachment portion 41R, and the left guide portion 42L may be supported by the left plate of the spreader body 45 behind the left attachment portion 41L. The right guide portion 42R may be a roller disposed to the right of the right plate of the spreader body 45 and rotatable with respect to the spreader body 45 about an axis in the left-right direction, and the left guide portion 42L may be a roller disposed to the left of the left plate of the spreader body 45 and rotatable with respect to the spreader body 45 about an axis in the left-right direction.

[0066] FIG. 13 is a plan view showing a state when the upper spreader 40 is guided by the right guide rail 71R and the left guide rail 71L, that is, a view of the upper spreader 40, the right guide rail 71R, and the left guide rail 71L as seen from above. As shown in FIG. 13, when the upper spreader 40 is guided by the right guide rail 71R and the left guide rail 71L, the spreader body 45 of the upper spreader 40 is disposed between the right guide rail 71R and the left guide rail 71L, the right guided portion 42R is disposed directly above the right guide rail 71R, and the left guided portion 42L is disposed directly above the left guide rail 71L. The width (dimension in the left-right direction) of the spreader body 45 of the upper spreader 40 is smaller than the distance L1 between the right guide rail 71R and the left guide rail 71L. The distance between the right end of the right guided portion 42R and the left end of the left guided portion 42L is larger than the distance L1 and smaller than the distance L2 between the left side surface of the right side wall 73R and the right side surface of the left side wall 73L, which will be described later.

[0067] In the modification of the crane 10, a spreader transfer operation, which is a transfer operation of moving the upper spreader 40 from the first attachment portions (the first right attachment portion 61R and the first left attachment portion 61L) for the crane specification to the second attachment portions (the second right attachment portion 62R and the second left attachment portion 62L) for the tower specification and attaching the upper spreader 40 to the second attachment portions, and at least one of the spreader transfer operations, which is a transfer operation of moving the upper spreader 40 from the second attachment portions for the tower specification to the first attachment portions for the crane specification and attaching the upper spreader 40 to the first attachment portions, is performed.

[0068] Hereinafter, the spreader transfer device 70, the crane 10, and the spreader transfer method according to the embodiments of the present disclosure will be specifically described. The embodiments of the present disclosure include the following first to thirteenth aspects.

[0069] [First Aspect] As shown in FIGS. 3 to 5, the spreader transfer device 70 according to the first aspect includes a right guide rail 71R and a left guide rail 71L that guide the upper spreader 40 between the first mounting portion and the second mounting portion. The right guide rail 71R and the left guide rail 71L have a shape such that when the boom 14 is in a collapsed state, the right guided portion 42R and the left guided portion 42L of the upper spreader 40 move along the right guide rail 71R and the left guide rail 71L, respectively, so that the right guided portion 42R can cross the first right mounting portion 61R and the left guided portion 42L can cross the first left mounting portion 61L.

[0070] In this first aspect, in the spreader transfer operation as shown in FIGS. 6 and 7, by simply moving the right guided portion 42R and the left guided portion 42L of the upper spreader 40 along the right guide rail 71R and the left guide rail 71L, contact between the right guided portion 42R and the first right mounting portion 61R of the first right protrusion 51R is avoided, and contact between the left guided portion 42L and the first left mounting portion 61L of the first left protrusion 51L is avoided while the upper spreader 40 can be transferred. Thereby, the workability of the spreader transfer operation is improved.

[0071] In a crane not equipped with a spreader transfer device, it is necessary to transfer the upper spreader 40 from one of the first mounting portion and the second mounting portion to the other while lifting the upper spreader 40 by an auxiliary crane or the like (not shown). On the other hand, in the present embodiment, the upper spreader 40 can be transferred from one of the first mounting portion and the second mounting portion to the other without using an auxiliary crane. Further, in the present embodiment, even when using an auxiliary crane, the workability when transferring the upper spreader 40 from one of the first mounting portion and the second mounting portion to the other can be improved as compared with the conventional case.

[0072] In this embodiment, when the boom 14 is in the stowed state, the right guide rail 71R and the left guide rail 71L are such that the right guided part 42R and the left guided part 42L move along the right guide rail 71R and the left guide rail 71L respectively, so that the right guided part 42R can cross the first right mounting part 61R and the left guided part 42L can cross the first left mounting part 61L. Moreover, the lower surface of the upper spreader 40 (the lower surface of the lower plate of the spreader body 45) may have a shape that can cross the first right mounting part 61R and the first left mounting part 61L, or the entire upper spreader 40 may have a shape that can cross the first right mounting part 61R and the first left mounting part 61L.

[0073] The spreader transfer device 70 includes a pair of left and right transfer members 70R and 70L. The right transfer member 70R on the right side has a right guide rail 71R, and the left transfer member 70L on the left side has a left guide rail 71L.

[0074] In addition, in this embodiment, the right transfer member 70R further includes a right side wall 73R that stands upward from the right edge of the right guide rail 71R, and the left transfer member 70L further includes a left side wall 73L that stands upward from the left edge of the left guide rail 71L. The right side wall 73R restricts the right guided part 42R of the upper spreader from moving further to the right than the right guide rail 71R, and the left side wall 73L restricts the left guided part 42L of the upper spreader from moving further to the left than the left guide rail 71L. Thereby, the right guided part 42R and the left guided part 42L of the upper spreader 40 can move in a more stable posture along the right guide rail 71R and the left guide rail 71L.

[0075] The right guide rail 71R, for example, as shown in FIG. 4, in a state where the boom 14 is laid down, is behind the first right attachment portion 61R of the first right protrusion 51R and at a position at the same height as the first right attachment portion 61R or at a position below the first right attachment portion 61R, a rear end portion E1, an intermediate portion M at a position above the first right attachment portion 61R (i.e., the intermediate portion M at a position above the rear end portion E1), and a front end portion E2 at a position in front of the first right attachment portion 61R and below the intermediate portion M. The shape of the left guide rail 71L may also be the same as that of the right guide rail 71R. That is, the left guide rail 71L may have a rear end portion E1, an intermediate portion M, and a front end portion E2.

[0076] The upper view (A) of FIG. 6 shows a state when the right guided portion 42R of the upper spreader 40 is located at the rear end portion E1 of the right guide rail 71R. The central view (B) of FIG. 6 shows a state when the right guided portion 42R of the upper spreader 40 is located at the intermediate portion M of the right guide rail 71R. The lower view (C) of FIG. 6 shows a state when the right guided portion 42R of the upper spreader 40 is located at the front end portion E2 of the right guide rail 71R. The right guided portion 42R of the upper spreader 40 moves obliquely upward along the right guide rail 71R as indicated by an arrow in the upper view (A) of FIG. 6 from a position corresponding to the rear end portion E1 in the upper view (A) of FIG. 6 to reach the intermediate portion M shown in the central view (B) of FIG. 6. Then, the right guided portion 42R of the upper spreader 40 moves obliquely downward along the right guide rail 71R as indicated by an arrow in the central view (B) of FIG. 6 from a position corresponding to the intermediate portion M in the central view (B) of FIG. 6 to get over the first right attachment portion 61R and reach the front end portion E2 shown in the lower view (C) of FIG. 6. The movement path of the left guided portion 42L of the upper spreader 40 is the same as the above.

[0077] Further, the reverse movement paths of the right guided portion 42R and the left guided portion 42L of the upper spreader 40 are as follows, for example. That is, the right guided portion 42R of the upper spreader 40 moves from the position corresponding to the front end portion E2 to the position corresponding to the middle portion M along the right guide rail 71R, and further moves along the right guide rail 71R toward the rear end portion E1 to cross over the first right attachment portion 61R and reach the rear end portion E1. The movement path of the left guided portion 42L of the upper spreader 40 is the same as the above.

[0078] [Second Aspect] The crane 10 according to the second aspect includes a boom 14, a lower spreader 17, an upper spreader 40, a first right protruding portion 51R, a first left protruding portion 51L, a second right protruding portion 52R, a second left protruding portion 52L, and a spreader transfer device 70 according to the first aspect.

[0079] In the crane 10 according to this second aspect, the workability of the spreader transfer work is improved.

[0080] [Third Aspect] The crane 10 according to the third aspect preferably further includes the following configuration in the crane 10 according to the second aspect. That is, in the crane 10 according to the third aspect, the spreader transfer device 70 includes a right rail support portion 72R that supports the right guide rail 71R and a left rail support portion 72L that supports the left guide rail 71L. The right rail support portion 72R is preferably detachably supported by at least one (mounting portion) of the boom 14, the first right protruding portion 51R, and the second right protruding portion 52R, and the left rail support portion 72L is preferably detachably supported by at least one (mounting portion) of the boom 14, the first left protruding portion 51L, and the second left protruding portion 52L.

[0081] In this third aspect, after the spreader transfer work is completed, the spreader transfer device 70 can be removed from the mounting portion. Therefore, the spreader transfer device 70 does not interfere with other work performed before and after the spreader transfer work.

[0082] The relocation member 70R on the right has a right rail support portion 72R, and the relocation member 70L on the left has a left rail support portion 72L.

[0083] [Fourth Aspect] The crane 10 according to the fourth aspect may further have the following configuration in the crane 10 according to the second aspect. That is, in the crane 10 according to the fourth aspect, the spreader relocation device 70 includes a right rail support portion 72R that supports the right guide rail 71R and a left rail support portion 72L that supports the left guide rail 71L. The right rail support portion 72R may be detachably supported by at least one of the first right protruding portion 51R and the second right protruding portion 52R, and the left rail support portion 72L may be detachably supported by at least one of the first left protruding portion 51L and the second left protruding portion 52L.

[0084] In this fourth aspect, without modifying the boom 14, the relocation member 70R on the right side of the spreader relocation device 70 can be attached to at least one of the first right protruding portion 51R and the second right protruding portion 52R, and the relocation member 70L on the left side of the spreader relocation device 70 can be attached to at least one of the first left protruding portion 51L and the second left protruding portion 52L.

[0085] [Fifth Aspect] The crane 10 according to the fifth aspect preferably further includes the following configuration in the crane 10 according to any one of the second to fourth aspects. That is, in the crane 10 according to the fifth aspect, as shown in FIG. 11, the spreader transfer device 70 preferably includes an upper right guide rail 74R that is disposed at an interval above the right guide rail 71R and extends along the right guide rail 71R, and an upper left guide rail 74L that is disposed at an interval above the left guide rail 71L and extends along the left guide rail 71L. In this case, the right transfer member 70R has the upper right guide rail 74R, and the left transfer member 70L has the upper left guide rail 74L. As shown in FIG. 11, the upper right guide rail 74R may be supported by, for example, the right side wall 73R, and the upper left guide rail 74L may be supported by the left side wall 73L.

[0086] In this fifth aspect, in the spreader transfer operation performed with the boom 14 in the collapsed state as shown in FIG. 2, when the right guided portion 42R of the upper spreader 40 moves along the right guide rail 71R and the left guided portion 42L of the upper spreader 40 moves along the left guide rail 71L, even when an upward external force acts on the upper spreader 40, the upper right guide rail 74R and the upper left guide rail 74L limit the upward movement of the right guided portion 42R and the left guided portion 42L of the upper spreader 40. Therefore, the spreader transfer operation can be performed while maintaining the state in which the right guided portion 42R and the left guided portion 42L are close to or in contact with the right guide rail 71R and the left guide rail 71L, respectively. Examples of the external force include, for example, the force acting on the upper spreader 40 from the boom hoisting rope 21 and the force acting on the upper spreader 40 from the boom guy line 19.

[0087] [Sixth Aspect] The crane 10 according to the sixth aspect preferably further has the following configuration in the crane 10 according to the fifth aspect. That is, in the crane 10 according to the sixth aspect, at least one of both ends of the upper right guide rail 74R preferably has a shape extending obliquely upward, and at least one of both ends of the upper left guide rail 74L preferably has a shape extending obliquely upward.

[0088] In this sixth aspect, the operation of inserting the right guided portion 42R of the upper spreader 40 between the right guide rail 71R and the upper right guide rail 74R can be efficiently performed, and the operation of inserting the left guided portion 42L of the upper spreader 40 between the left guide rail 71L and the upper left guide rail 74L can be efficiently performed.

[0089] In the specific example shown in FIG. 11, the rear end portion of the upper right guide rail 74R is at a position higher than the front end portion of the upper right guide rail 74R, and the rear end portion of the upper left guide rail 74L is at a position higher than the front end portion of the upper left guide rail 74L. The distance between the rear end portion of the right guide rail 71R and the rear end portion of the upper right guide rail 74R is larger than the distance between the front end portion of the right guide rail 71R and the front end portion of the upper right guide rail 74R, and the distance between the rear end portion of the left guide rail 71L and the rear end portion of the upper left guide rail 74L is larger than the distance between the front end portion of the left guide rail 71L and the front end portion of the upper left guide rail 74L. Thereby, the operation of inserting the right guided portion 42R of the upper spreader 40 between the rear end portion of the right guide rail 71R and the rear end portion of the upper right guide rail 74R can be efficiently performed, and the operation of inserting the left guided portion 42L of the upper spreader 40 between the rear end portion of the left guide rail 71L and the rear end portion of the upper left guide rail 74L can be efficiently performed.

[0090] [Seventh Aspect] The crane 10 according to the seventh aspect preferably further includes the following configuration in the crane 10 according to any one of the second to sixth aspects. That is, in the crane 10 according to the seventh aspect, as shown in FIG. 12, the first right protruding portion 51R and the first left protruding portion 51L are supported by the lower boom member 14A, and the second right protruding portion 52R and the second left protruding portion 52L may be supported by an intermediate boom member 14B connected to the lower boom member 14A. And the transfer member 70R on the right side of the spreader transfer device 70 is configured to be displaceable between a guide position P11 shown in the upper diagram of FIG. 12 and a retracted position P12 shown in the lower diagram of FIG. 12 while being supported by the second right protruding portion 52R, and the transfer member 70L on the left side of the spreader transfer device 70 is configured to be displaceable between the guide position P11 shown in the upper diagram of FIG. 12 and the retracted position P12 shown in the lower diagram of FIG. 12 while being supported by the second left protruding portion 52L. The guide position P11 shown in the upper diagram of FIG. 12 is a position for performing the spreader transfer operation, and the retracted position P12 shown in the lower diagram of FIG. 12 is preferably a position that is farther away from the connecting portion (specifically, the connector 143) between the lower boom member 14A and the intermediate boom member 14B connected thereto than the guide position P11. The switching between the guide position P11 and the retracted position P12 may be performed, for example, by changing the position of a pin hole into which a fixing member such as a pin or a bolt that fixes each of the right and left transfer members 70R and 70L of the spreader transfer device 70 to the corresponding protruding portion is inserted.

[0091] In this seventh aspect, when the spreader transfer operation is performed, each of the right and left transfer members 70R and 70L of the spreader transfer device 70 is arranged at the guide position P11, and after the completion of the spreader transfer operation, each of the right and left transfer members 70R and 70L of the spreader transfer device 70 can be arranged at the retracted position P12. Thereby, for example, in the connection operation of connecting the lower boom member 14A and the intermediate boom member 14B, the spreader transfer device 70 does not get in the way.

[0092] In addition, when the crane 10 is disassembled into a plurality of sections and each section is transported using a transporter such as a trailer, the transfer member 70R on the right side of the spreader transfer device 70 is supported by the second right protrusion 52R, and the transfer member 70L on the left side of the spreader transfer device 70 is supported by the second left protrusion 52L. That is, in this seventh aspect, it is not necessary to remove the transfer members 70R and 70L on the right and left sides of the spreader transfer device 70 from the second right protrusion 52R and the second left protrusion 52L during either the spreader transfer operation or transportation. This can save the trouble of managing (parts management) the spreader transfer device during transportation.

[0093] Also, in a state where the transfer members 70R and 70L on the right and left sides of the spreader transfer device 70 are each disposed at the guide position P11, when the upper ends of the transfer members 70R and 70L on the right and left sides are disposed above the upper ends of the protrusions 51R, 51L, 52R, and 52L, it is preferable that, by disposing the spreader transfer device 70 at the retracted position P12, the upper ends of the transfer members 70R and 70L are disposed below the upper ends of the protrusions 51R, 51L, 52R, and 52L. In this case, it becomes easier to avoid the height of the section including the spreader transfer device 70 exceeding the range of the height limit during transportation.

[0094] [Eighth Aspect] The crane 10 according to the eighth aspect preferably further has the following configuration in the crane 10 according to any one of the second to seventh aspects. That is, in the crane 10 according to the eighth aspect, the spreader transfer device 70 includes a right guide rail 71R and a left guide rail 71L.

[0095] In this eighth aspect, since the spreader transfer device 70 includes the right guide rail 71R and the left guide rail 71L, the right guided portion 42R and the left guided portion 42L of the upper spreader 40 can move in a more stable posture from one of the first attachment portion and the second attachment portion to the other along the right guide rail 71R and the left guide rail 71L compared to the case where the spreader transfer device 70 includes only one guide rail.

[0096] [Aspect 9] The crane 10 according to the ninth aspect preferably further has the following configuration in the crane 10 according to the eighth aspect. That is, in the crane 10 according to the ninth aspect, as shown in FIG. 10, the transfer member 70R on the right side of the spreader transfer device 70 includes a right rail support portion 72R that supports the right guide rail 71R, a left rail support portion 72L that supports the left guide rail 71L, a right inclined wall 75R that extends obliquely upward to the right above the right rail support portion 72R, and a left inclined wall 75L that extends obliquely upward to the left above the left rail support portion 72L.

[0097] In this ninth aspect, since the right inclined wall 75R extends obliquely upward to the right and the left inclined wall 75L extends obliquely upward to the left, in the spreader transfer operation, when the right guided portion 42R and the left guided portion 42L of the upper spreader 40 move along the right guide rail 71R and the left guide rail 71L respectively, an upward external force acts on the upper spreader 40. Even when the upper spreader 40 moves upward away from the right guide rail 71R and the left guide rail 71L, it is easy to return the right guided portion 42R and the left guided portion 42L of the upper spreader 40 to the right guide rail 71R and the left guide rail 71L. Specifically, when reducing the action of the external force and lowering the upper spreader 40, the right inclined wall 75R and the left inclined wall 75L can guide the right guided portion 42R and the left guided portion 42L of the upper spreader 40 to the right guide rail 71R and the left guide rail 71L even if the upper spreader 40 is somewhat offset to either the left or the right.

[0098] The right inclined wall 75R may extend obliquely upward to the right from the upper end of the right side wall 73R, or may extend obliquely upward to the right from the upper end of the right rail support portion 72R (for example, a position corresponding to the right side edge of the right guide rail 71R). Similarly, the left inclined wall 75L may extend obliquely upward to the left from the upper end of the left side wall 73L, or may extend obliquely upward to the left from the upper end of the left rail support portion 72L (for example, a position corresponding to the left side edge of the left guide rail 71L).

[0099] [Aspect 10] The crane 10 according to the 10th aspect preferably further includes the following configuration in the crane 10 according to any one of the 2nd to 9th aspects. That is, the crane 10 according to the 10th aspect may include a right guide member 80R and a left guide member 80L for guiding the upper spreader 40 that descends by increasing the distance between the lower spreader 17 and the upper spreader 40 when the boom 14 is in a collapsed state (see FIGS. 3 and 4). In this case, the right guided portion 42R and the left guided portion 42L are configured to move along the right guide rail 71R and the left guide rail 71L when the upper spreader 40 is relocated using the spreader relocation device 70, and are preferably configured to move along the right guide member 80R and the left guide member 80L when the upper spreader 40 is guided using the right guide member 80R and the left guide member 80L.

[0100] In this 10th aspect, the right guided portion 42R and the left guided portion 42L can be used for both the relocation operation of the upper spreader 40 using the spreader relocation device 70 and the guiding operation of the upper spreader 40 using the right guide member 80R and the left guide member 80L. When guiding the upper spreader 40 using the right guide member 80R and the left guide member 80L, each of the right guide member 80R and the left guide member 80L may be switched from the collapsed posture shown in FIGS. 3 and 4 to an upright posture (not shown).

[0101] [Aspect 11] The crane 10 according to the 11th aspect preferably further includes the following configuration in the crane 10 according to any one of the 2nd to 10th aspects. That is, the crane 10 according to the 11th aspect preferably includes a traction device for moving the upper spreader 40 along the guide rail from the first attachment portion to the second attachment portion.

[0102] In this eleventh aspect, since the traction device assists the spreader relocation operation, the workability of the spreader relocation operation is further improved. The traction device may be, for example, the boom hoist winch 16, the jib hoist winch 25, the main hoist winch 26, a supplementary winch (not shown), or another traction device (for example, the twelfth aspect described later).

[0103] As shown in FIG. 7, for example, it is preferable that the traction device attaches two ropes R to the right rope attachment portion 43R and the left rope attachment portion 43L, arranges these ropes R in a V shape, and is pulled by one rope R. Thereby, the posture of the upper spreader 40 during movement is stabilized. Further, as shown in FIG. 8, the traction device may be configured to pull the two ropes R attached to the right rope attachment portion 43R and the left rope attachment portion 43L. As shown in FIG. 9, the traction device may be configured to pull one rope R attached to the upper spreader 40.

[0104] [Twelfth Aspect] The crane 10 according to the twelfth aspect preferably further includes the following configuration in the crane 10 according to the eleventh aspect. That is, in the crane 10 according to the twelfth aspect, the traction device is preferably a chain block (not shown) with a torque control function.

[0105] In this twelfth aspect, when the traction device is a chain block, excessive tension does not act on the upper spreader 40, so it is possible to prevent excessive load on components related to the relocation operation such as the upper spreader 40 and the spreader relocation device 70.

[0106] [Thirteenth Aspect] The spreader relocation method according to the thirteenth aspect is a spreader relocation method using any one of the cranes according to the second to twelfth aspects, and includes moving the upper spreader 40 from one of the first attachment portion and the second attachment portion to the other along the right guide rail 71R and the left guide rail 71L.

[0107] In this 13th aspect, in the spreader relocation work, by simply moving the right guided portion 42R and the left guided portion 42L of the upper spreader 40 along the right guide rail 71R and the left guide rail 71L, it is possible to avoid the right guided portion 42R from contacting the first right attachment portion 61R of the first right protruding portion 51R, and to relocate the upper spreader 40 while avoiding the left guided portion 42L from contacting the first left attachment portion 61L of the first left protruding portion 51L. Thereby, the workability of the spreader relocation work is improved.

[0108] [Modification Example] Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above embodiments and includes, for example, the following modification examples.

[0109] (A) Regarding the spreader relocation device In the above embodiment, the spreader relocation device includes two guide rails, but the spreader relocation device in the present disclosure may include only one guide rail.

[0110] (B) Regarding the first attachment portion and the second attachment portion In the above embodiment, the first attachment portion is located behind the second attachment portion, but in the crane according to the present disclosure, the first attachment portion may be located in front of the second attachment portion.

Explanation of Reference Numerals

[0111] 10: Crane 14: Boom 14A: Lower boom member 14B: Intermediate boom member 14C: Upper boom member 15: Jib 16: Boom hoist winch 17: Lower spreader 19: Boom guy line 25: Jib hoist winch 26: Main winch 40: Upper spreader 41L: Left attachment part 41R: Right attachment part 42L: Left guided part 42R: Right guided part 43L: Left rope attachment part 43R: Right rope attachment part 51L: First left protruding part 51R: First right protruding part 52L: Second left protruding part 52R: Second right protruding part 61L: First left attachment part 61R: First right attachment part 62L: Second left attachment part 62R: Second right attachment part 70: Spreader transfer device 70L: Left transfer member 70R: Right transfer member 71L: Left guide rail 71R: Right guide rail 72L: Left rail support part 72R: Right rail support part 74L: Upper left guide rail 74R: Upper right guide rail 75L: Left inclined wall 75R: Right inclined wall 80L: Left guide member 80R: Right guide member 141: Main pipe 142: Inclined pipe 143: Connector P11: Guide position P12: Retracted position

Claims

1. A boom, a lower spreader and an upper spreader for raising and lowering the boom, a first attachment portion for removably attaching an attachment portion of the upper spreader, and a first protrusion protruding from the boom, A second attachment portion for removably attaching the attachment portion of the upper spreader, and a second protrusion protruding from the boom at a position separated from the first protrusion in the longitudinal direction of the boom. A spreader transfer device for a crane, comprising: A guide rail for guiding the upper spreader between the first attachment portion and the second attachment portion is provided; The upper spreader has a guided portion; The guide rail has a shape in which the guided portion can cross the first attachment portion by moving along the guide rail when the boom is in a collapsed state. A spreader transfer device.

2. The boom, The lower spreader, The upper spreader, The first protrusion, The second protrusion, A crane comprising the spreader transfer device according to claim 1.

3. The spreader transfer device includes a rail support portion that supports the guide rail, The rail support portion is removably supported by at least one of the boom, the first protrusion, and the second protrusion. The crane according to claim 2.

4. The spreader transfer device includes a rail support portion that supports the guide rail, The rail support portion is supported by at least one of the first protrusion and the second protrusion. The crane according to claim 2.

5. The crane according to claim 2, wherein the spreader transfer device includes an upper guide rail that is disposed at an interval above the guide rail and extends along the guide rail.

6. At least one of both ends of the upper guide rail has a shape that extends obliquely upward. The crane according to claim 5.

7. The boom includes a first boom member and a second boom member connected to the first boom member, The first protrusion is supported by the first boom member, and the second protrusion is supported by the second boom member. The spreader transfer device is configured to be displaceable between a guide position and a retracted position while being supported by at least one of the boom, the first protruding portion, and the second protruding portion. The guide position is a position for guiding the upper spreader between the first attachment portion and the second attachment portion, and the retracted position is a position farther from the connection portion between the first boom member and the second boom member than the guide position. The crane according to claim 2.

8. The width direction of the boom is the left-right direction, the guide rail is a right guide rail, and the guided portion is a right guided portion. The upper spreader has a left guided portion. The spreader transfer device includes a left guide rail disposed at a distance to the left of the right guide rail for guiding the upper spreader between the first attachment portion and the second attachment portion. The left guide rail has a shape that allows the left guided portion to straddle the first attachment portion when the left guided portion moves along the left guide rail in a state where the boom is laid down. The crane according to claim 2.

9. The spreader transfer device a right rail support portion that supports the right guide rail; a left rail support portion that supports the left guide rail; a right inclined wall that extends obliquely upward to the right above the right rail support portion; a left inclined wall that extends obliquely upward to the left above the left rail support portion. The crane according to claim 8.

10. A guide member for guiding the upper spreader that descends by increasing the distance between the lower spreader and the upper spreader in a state where the boom is laid down to the first attachment portion. The guided portion is configured to move along the guide rail when the upper spreader is transferred using the spreader transfer device, and is configured to move along the guide member when the upper spreader is guided using the guide member. The crane according to claim 2.

11. The crane according to claim 2, further comprising a traction device for moving the upper spreader along the guide rail from the first attachment portion toward the second attachment portion.

12. The traction device is a chain block with a torque control function. The crane according to claim 11.

13. A spreader relocation method using the crane according to any one of Claims 2 to 12, comprising: relocating the spreader along the guide rail by moving the upper spreader from one of the first attachment portion and the second attachment portion to the other.

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