Crane device and attachment descent method

Abstract

To restrain a winding-up rope from being contacted on ground surface when a tip end part of an attachment lowers in such a condition that a hook is lowered from the tip end part of the attachment.SOLUTION: A hook 23 may be installed on a hook holder 60 capable of moving ground surface. A winding-up winch control part 53 controls actuation of a winding-up winch 27. The winding-up winch control part 53 performs winding-up control when an attachment, which causes the winding-up winch 27 to wind a winding-up rope 25, is lowered on the basis of attachment tip end position information acquired by an attachment tip end position acquisition unit (41) when a tip end part of the attachment A lowers in such a condition that the hook 23 is installed on the hook holder 60.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a crane apparatus equipped with an attachment, and a method for lowering the attachment. [Background technology]

[0002] For example, Patent Document 1 describes a hook holder (a hook stand in the document) that moves the hook without interfering with the ground as the tip of the attachment (a jib in the document) moves (see the abstract and drawings of the document). The hook holder described in the document is intended to assist in assembling the crane (see claim 1, etc. of the document). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-142704 Summary of the Invention [Problem to be solved by the invention]

[0004] When a crane is in a working position (see Figure 3 of the document), the attachment is lowered to the ground, and the attachment is disassembled, the tip of the attachment comes into contact with the ground (as shown in Figure 2 of the document). When the attachment is lowered, the hook is placed on the hook holder and the tip of the attachment is lowered without the tip of the attachment being in contact with the ground. This may cause the hoisting rope connected between the tip of the attachment and the hook to sag and come into contact with the ground.

[0005] Therefore, an object of the present invention is to provide a crane apparatus and an attachment lowering method that can prevent the hoisting rope from coming into contact with the ground when the tip of the attachment is lowered with the hook lowered from the tip of the attachment. [Means for solving the problem]

[0006] The crane apparatus includes a crane body, an attachment, an attachment tip position information acquisition unit, a hoisting rope, a hoisting winch, a hook, and a hoisting winch control unit. The attachment is attached to the crane body so that it can be raised and lowered. The attachment tip position information acquisition unit acquires attachment tip position information relating to the position of the tip of the attachment. The hoisting rope is attached to the tip of the attachment. The hoisting winch winds and unwinds the hoisting rope. The hook may be mounted on a hook holder that is movable on the ground and can be suspended from the tip of the attachment via the hoisting rope. The hoisting winch control unit controls the operation of the hoisting winch. When the tip of the attachment descends with the hook placed on the hook holder, the hoisting winch control unit performs hoisting control during attachment descent, causing the hoisting winch to wind up the hoisting rope, based on the attachment tip position information acquired by the attachment tip position information acquisition unit.

[0007] The attachment lowering method is used for a crane. The crane includes a crane body, an attachment, a hoisting rope, a hoisting winch, and a hook. The attachment is attached to the crane body so that it can be raised and lowered. The hoisting rope is attached to the tip of the attachment. The hoisting winch winds and unwinds the hoisting rope. The hook may be mounted on a hook holder that is movable on the ground and can be suspended from the tip of the attachment via the hoisting rope. The attachment lowering method includes an attachment tip lowering step, an attachment tip position information acquisition step, and an attachment lowering hoisting step. In the attachment tip lowering step, the tip of the attachment is lowered with the hook mounted on the hook holder. In the attachment tip position information acquisition step, attachment tip position information regarding the position of the tip of the attachment is acquired when the attachment tip lowering step is performed. In the attachment lowering hoisting step, when the attachment tip lowering step is performed, the hoisting winch winds up the hoisting rope based on the attachment tip position information acquired in the attachment tip position information acquisition step. [Effects of the Invention]

[0008] Each of the above-described crane apparatus and attachment lowering method can prevent the hoisting rope from coming into contact with the ground when the tip of the attachment is lowered with the hook lowered from the tip of the attachment. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a diagram showing a crane apparatus 1, in which a crane 10 in a working posture and the like are viewed from the lateral direction Y. FIG. [Figure 2] 2 is a block diagram showing a controller 50 and the like of the crane apparatus 1 shown in FIG. 1. FIG. [Figure 3]1. FIG. 2 is a view from the lateral direction Y showing a state in which the jib tip 17a is lowered from the state shown in FIG. [Figure 4] 4 is a view from the lateral direction Y showing a state in which the jib tip 17a is lowered from the state shown in FIG. 3. FIG. [Figure 5] 5 is a view of the jib tip 17a and the hook holder 60 shown in FIG. 4 as viewed from the front side X1. [Figure 6] 5 is a view of the jib tip portion 17a and the hook holder 60 shown in FIG. 4 as viewed from the upper side Z1. [Figure 7] 5 is a view of the jib tip 17a shown in FIG. 4 in a state where it has landed on the ground, as viewed from the lateral direction Y. FIG. [Figure 8] 8 is a view of the attachment A shown in FIG. 7 in a state where the entire attachment A has been lowered, as viewed from the lateral direction Y. FIG. [Figure 9] 4 is a flowchart showing the procedure for lowering an attachment A using the crane apparatus 1 shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] The crane apparatus 1 shown in FIG. 1 will be described with reference to FIGS.

[0011] The crane apparatus 1 is an apparatus including a crane 10. The crane apparatus 1 is configured to easily perform an operation (attachment A lowering operation) of lowering an attachment A (e.g., a boom 13 and a jib 17). The crane apparatus 1 includes the crane 10, an attachment operating unit 33 shown in FIG. 2, an information acquisition unit 40, a controller 50, and a hook holder 60 shown in FIG. 1.

[0012] The crane 10 is a machine that performs work, such as lifting a load. The crane 10 is, for example, a construction machine that performs construction work. The crane 10 includes a crane body 11, a boom 13 (attachment A), a boom hoisting device 15, a jib 17 (attachment A), a jib hoisting device 19, a hook hoisting device 20, and a drive control unit 31 (see FIG. 2).

[0013] The crane body 11 is the main body of the crane 10. The crane body 11 includes a lower body 11a and an upper rotating body 11b. The lower body 11a supports the upper rotating body 11b. The lower body 11a may be a structure fixed to the ground G, or may be mobile. The crane 10 may be a fixed crane or a mobile crane. When the lower body 11a is mobile (a lower traveling body), the lower body 11a may be equipped with crawlers or wheels. For example, the crane 10 may be a crawler crane or a wheeled crane. The upper rotating body 11b is rotatably mounted on the lower body 11a. A boom 13 and the like are attached to the upper rotating body 11b. The upper rotating body 11b includes a cab 11b1. The cab 11b1 is a section where an operator can operate the crane 10.

[0014] (direction) The direction in which the rotation axis of the upper rotating body 11b for rotating relative to the lower body 11a extends is defined as the up-down direction Z. In the up-down direction Z, the side (facing) from the lower body 11a toward the upper rotating body 11b is defined as the upper side Z1, and the opposite side is defined as the lower side Z2. The direction in which the rotation axis of the boom 13 for raising and lowering relative to the upper rotating body 11b (crane body 11) extends is defined as the lateral direction Y. The direction perpendicular to both the up-down direction Z and the lateral direction Y is defined as the front-to-rear direction X. In the front-to-rear direction X, the side from the upper rotating body 11b toward the boom 13 when the boom 13 is in a lowered position (see Figure 8, described below) is defined as the front side X1, and the opposite side is defined as the rear side X2.

[0015] The attachment A is attached to the upper rotating body 11b so that it can be raised and lowered (rotated in the vertical direction Z). The attachment A may include a boom 13 and a jib 17. Alternatively, the attachment A may include the boom 13 but not the jib 17. The following mainly describes the case where the attachment A includes the boom 13 and the jib 17.

[0016] The boom 13 is attached to the upper rotating body 11b so as to be able to be raised and lowered (rotated in the vertical direction Z). As shown in FIG. 8, the boom 13 can be in a lowered position (lying down position) so that the central axis of the boom 13 extending in the longitudinal direction of the boom 13 extends horizontally or approximately horizontally. The boom 13 shown in FIG. 1 may have a lattice structure (may be a lattice boom), a box-shaped structure, or be extendable (may be a telescopic boom). The same applies to the jib 17 and the strut 19a, which may have a lattice structure or a box-shaped structure. The angle formed between the central axis of the boom 13 extending in the longitudinal direction of the boom 13 and the horizontal direction is defined as the boom hoisting angle θ13.

[0017] The boom hoisting device 15 (attachment hoisting device) is a device that raises and lowers the boom 13 relative to the upper rotating body 11b. The boom hoisting device 15 includes a mast 15a, a lower spreader 15b, an upper spreader 15c, a boom guy line 15d, a boom hoist rope 15e, and a boom hoist winch 15w. The mast 15a is attached to the upper rotating body 11b so that it can be raised and lowered. The lower spreader 15b has multiple sheaves and is provided at the rear X2 end of the upper rotating body 11b. The upper spreader 15c has multiple sheaves and is provided at the tip of the mast 15a. The boom guy line 15d is connected to the tip of the mast 15a and the tip of the boom 13. The boom hoist rope 15e is hung between the sheaves of the lower spreader 15b and the sheaves of the upper spreader 15c. The boom hoisting winch 15w is a winch. The boom hoisting winch 15w may be mounted on the upper rotating body 11b or the mast 15a. The boom hoisting winch 15w winds and unwinds the boom hoist rope 15e. This changes the distance between the lower spreader 15b and the upper spreader 15c. This causes the mast 15a to rise and fall relative to the upper rotating body 11b. Because the tip of the mast 15a and the tip of the boom 13 are connected by the boom guy line 15d, when the mast 15a rises and falls relative to the upper rotating body 11b, the boom 13 rises and falls relative to the upper rotating body 11b.

[0018] The configuration of the boom hoisting device 15 can be modified in various ways. For example, a gantry (not shown) may be provided instead of the mast 15a. In this case, the gantry includes a compression member and a tension member. The compression member is attached to the upper rotating body 11b and is located in the same position as the mast 15a. The tension member is connected to the tip of the compression member and the rear end of the upper rotating body 11b. The tip of the compression member is connected to the tip of the boom 13 by a boom guy line 15d and a boom hoist rope 15e. In this case, the boom hoisting winch 15w reels in and pays out the boom hoist rope 15e, thereby raising and lowering the boom 13 relative to the upper rotating body 11b. The crane 10 may also include multiple masts 15a, or it may include a gantry and a mast 15a.

[0019] The jib 17 is attached to the boom 13 so that it can be raised and lowered. The reason for providing the jib 17 is as follows: It is preferable that the crane 10 be able to carry a load (suspended load) high and far. Here, if the crane 10 is equipped with the boom 13 but not the jib 17, if there is an obstacle (such as a tall building) near (in front of) the crane 10, the obstacle will get in the way and make it difficult to carry the load far. Therefore, the jib 17 is attached to the tip of the boom 13 so that it can be raised and lowered. If the length of the boom 13 is equal to or shorter than the height of the obstacle, the jib 17 can move (swivel, raise and lower) without interfering with the obstacle, and the load can be carried far away by passing over the obstacle. The length of the jib 17 (the length of the jib 17 in the longitudinal direction of the jib 17) may be shorter than, the same as, or longer than the length of the boom 13 (the length of the boom 13 in the longitudinal direction of the boom 13). The angle formed between the central axis of the boom 13 extending in the longitudinal direction of the boom 13 and the central axis of the jib 17 extending in the longitudinal direction of the jib 17 is defined as the jib offset angle θ17. The tip of the jib 17 (the end opposite to the end (base end) attached to the boom 13) is defined as the jib tip 17a (the tip of the attachment A). The position of the jib tip 17a is also referred to as the jib tip position P17a (attachment tip position). Note that when the attachment A is equipped with the boom 13 but not the jib 17, the tip of the attachment A is the tip of the boom 13, and the attachment tip position is the position of the tip of the boom 13. The jib 17 is equipped with a jib main body 17b, which is the main body of the jib 17, and a jib tip roller 17c.

[0020] The jib tip roller 17c enables the jib tip portion 17a to move relative to the ground G when the jib tip portion 17a is in contact with the ground (see FIGS. 7 and 8). The jib tip roller 17c is provided on the jib tip portion 17a. The jib tip roller 17c is rotatable relative to the jib main body portion 17b.

[0021] This jib tip roller 17c may be detachably attached to the tip of the jib main body 17b. The jib tip roller 17c is attached to the jib main body 17b when the jib tip 17a is in a state where it is grounded (specifically, when assembling and disassembling the crane 10). It is preferable that the jib tip roller 17c be detached from the jib main body 17b when the crane 10 is in operation. The reason for this is as follows. Because the jib tip roller 17c is heavy, if the jib tip roller 17c remains attached to the jib main body 17b when the crane 10 is in operation, the lifting capacity of the crane 10 will decrease. Therefore, in order to ensure the lifting capacity when the crane 10 is in operation, it is preferable that the jib tip roller 17c be detached from the jib main body 17b when the crane 10 is in operation. The timing for attaching and detaching the jib tip roller 17c to and from the jib main body 17b is as follows. When assembling the crane 10, the jib tip roller 17c is removed (separated) from the jib main body 17b at the timing when (for example, just before) the jib tip portion 17a leaves the ground G. When disassembling the crane 10, the jib tip roller 17c is attached (mounted) to the jib main body 17b at the timing when the jib main body 17b approaches the ground G.

[0022] The jib hoisting device 19 (attachment hoisting device) is a device that raises and lowers the jib 17 relative to the boom 13. The jib hoisting device 19 includes struts 19a (rear struts 19a1 and front struts 19a2), a jib guy line 19b, a strut guy line 19c, a jib hoist rope 19d, and a jib hoist winch 19w. The rear strut 19a1 includes a sheave and is rotatably attached to the tip of the boom 13. The front strut 19a2 includes a sheave and is rotatably attached to the tip of the boom 13 or the base end of the jib 17. When the crane 10 is in a posture ready for work (crane posture), the front strut 19a2 is positioned above Z1 and forward X1 of the rear strut 19a1. The jib guy line 19b is connected to the tip of the front strut 19a2 and the jib tip 17a. The strut guy line 19c is connected to the boom 13 and the tip of the rear strut 19a1. The jib hoist rope 19d is hung between the sheave of the rear strut 19a1 and the sheave of the front strut 19a2. The jib hoist winch 19w is a winch mounted on the upper rotating body 11b or the boom 13. The jib hoist winch 19w winds and pays out the jib hoist rope 19d. This changes the distance between the tip of the rear strut 19a1 and the tip of the front strut 19a2. This causes the front strut 19a2 to rise and fall relative to the boom 13. Because the tip of the front strut 19a2 and the tip of the jib 17 are connected by the jib guy line 19b, when the front strut 19a2 rises and falls relative to the boom 13, the jib 17 also rises and falls relative to the boom 13.

[0023] The configuration of the jib hoisting device 19 can be modified in various ways. For example, a strut 19a may be provided in which the tip of a rear strut 19a1 and the tip of a front strut 19a2 are connected and fixed to each other. Only one strut 19a may be provided. In this case, for example, the tip of one strut 19a is connected to the tip of the jib 17 by a jib guy line 19b. When one strut 19a is hoisted relative to the boom 13, the jib 17 is hoisted relative to the boom 13. Note that both the boom 13 and the jib 17 may be hoisted or at least one of the boom 13 and the jib 17 may not be hoisted during operation of the crane 10.

[0024] The hook hoisting device 20 is a device that hoists and lowers (raises and lowers) the hook 23. The hook hoisting device 20 includes a point sheave 21, a hoisting rope 25, the hook 23, and a hoisting winch 27.

[0025] The point sheave 21 is provided at the jib tip 17a. The point sheave 21 is a sheave (pulley) that changes the direction of the hoisting rope 25. The point sheave 21 may be provided at only one location, or at multiple locations. For example, the point sheave 21 may be provided coaxially with the jib tip roller 17c, or may be provided closer to the base end of the jib 17 than the jib tip roller 17c.

[0026] The hook 23 can be suspended from the jib tip 17a via a hoisting rope 25. The hook 23 may be mounted on a hook holder 60 (described later). Only one hook 23 may be provided, or multiple hooks 23 may be provided. The hook 23 comprises a hook main body 23a and a hook-shaped portion 23b. The hook main body 23a is the portion to which the hoisting rope 25 is attached. The hoisting rope 25 is fixed to the hook main body 23a. Alternatively, a sheave is provided in the hook main body 23a, and the hoisting rope 25 is hung on this sheave. The hook-shaped portion 23b is hook-shaped. A load can be hung on the hook-shaped portion 23b via a rope or the like (not shown).

[0027] The hoisting rope 25 is attached to the jib tip 17a, and more specifically, is hung around the point sheave 21. The hoisting rope 25 is attached to the hook 23. The hoisting rope 25 between the hook 23 and the point sheave 21 may be a single-rope or multiple-rope (multiple-rope) hoisting. In the "single-rope" case, one hoisting rope 25 suspended from the point sheave 21 is attached and fixed to the hook 23. In the "multiple-rope" case, the hoisting rope 25 is hung around the sheave provided on the hook 23 and the point sheave 21, for example, by being reeled around the sheave provided on the hook 23 and the point sheave 21. Note that Figures 3, 4, 7, and 8 show an example in which the hoisting rope 25 is multiple-rope hung around the hook 23. Also, Figures 5 and 6 show an example in which the hoisting rope 25 is single-rope hung around the hook 23, and only the approximate position of the center axis of the hoisting rope 25 is illustrated.

[0028] The hoisting winch 27 winds in and pays out the hoisting rope 25 shown in Fig. 1. The hoisting winch 27 is a winch mounted on the upper rotating body 11b or the boom 13. When the hoisting winch 27 winds in and pays out the hoisting rope 25, the hook 23 (more specifically, the hook 23 in the air) is wound up and lowered.

[0029] The drive control unit 31 (see FIG. 2) controls the operation of the crane 10. For example, the drive control unit 31 is a hydraulic circuit that controls the boom hoisting winch 15w, the jib hoisting winch 19w, and the hoisting winch 27 (each of which is a hydraulic winch).

[0030] The attachment operation unit 33 (see FIG. 2) is used to operate the attachment A (boom 13 and jib 17). The attachment operation unit 33 may be operated by the operator of the crane 10. The attachment operation unit 33 may also be used to automatically operate the crane 10. The attachment operation unit 33 may be provided on the crane 10, for example, in the operator's cab 11b1. The attachment operation unit 33 may also be provided outside the crane 10, for example, in a device (remote control unit) that remotely controls the crane 10. The attachment operation unit 33 may include, for example, a lever (operation lever). In cases where the attachment operation unit 33 automatically operates the crane 10, the attachment operation unit 33 may be a part of the function of the controller 50 (for example, the attachment control unit 51).

[0031] The attachment operating unit 33 (see FIG. 2) can output a command to the upper rotating body 11b to raise or lower the boom 13 (a command to operate the boom hoist winch 15w). The attachment operating unit 33 can output a command to the boom 13 to raise or lower the jib 17 (a command to operate the jib hoist winch 19w). The attachment operating unit 33 can output a command to move the jib tip 17a (lowering or advancing, as described below). The attachment operating unit 33 may also be able to output a command to rotate the upper rotating body 11b to the lower body 11a.

[0032] The information acquisition unit 40 (see FIG. 2) acquires information related to the operation of the crane apparatus 1. This "acquisition" may be calculation or detection. The information acquisition unit 40 includes a jib tip position information acquisition unit 41 (attachment tip position information acquisition unit) (see FIG. 2) and a jib tip ground contact state acquisition unit 43 (attachment ground contact state acquisition unit) (see FIG. 2).

[0033] The jib tip position information acquisition unit 41 (attachment tip position information acquisition unit) (see FIG. 2) acquires jib tip position information (attachment tip position information), which is information relating to the position of the jib tip 17a (jib tip position P17a). This acquisition is referred to as a jib tip position information acquisition step (attachment tip position information acquisition step). The jib tip position information may include coordinate information of the jib tip position P17a (see Example A1 below), or may include information correlated with the jib tip position P17a (see Example A2 below).

[0034] [Example A1] A case will be described in which the jib tip position information acquired by the jib tip position information acquisition unit 41 (see FIG. 2) includes coordinate information of the jib tip position P17a. The reference position (origin position) of the coordinate of the jib tip position P17a may be set to a specific portion of the crane 10 (e.g., a specific portion of the lower body 11a) or may be set to the work site where the crane apparatus 1 performs work. The coordinate of the jib tip position P17a may include a coordinate axis in the up-down direction Z. The jib tip position information may also include information on the height (lifting height) of the jib tip 17a from the ground G. In this case, the jib tip position information acquisition unit 41 may acquire information from a lifting height meter provided on the crane 10. The coordinate of the jib tip position P17a may include a coordinate axis in the fore-aft direction X and a coordinate axis in the lateral direction Y (the rotation direction of the upper rotating body 11b). The coordinate of the jib tip position P17a may be acquired (e.g., calculated or detected) by various methods.

[0035] [Example A1a (Calculation)] The jib tip position information acquisition unit 41 may calculate the coordinates of the jib tip position P17a based on information about the attachment A. Specifically, the coordinates of the jib tip position P17a may be calculated based on the specifications of the attachment A and the posture of the attachment A. The "specifications of the attachment A" specifically include, for example, information about the length of the boom 13 and the length of the jib 17. The specifications of the attachment A may be information manually entered into the jib tip position information acquisition unit 41 by the operator, or may be information detected by a sensor or the like. The "posture of the attachment A" specifically includes, for example, information about the boom hoisting angle θ13 and the jib offset angle θ17. The information about the boom hoisting angle θ13 and the jib offset angle θ17 is detected by, for example, an angle sensor (not shown).

[0036] [Example A1b (Detection)] The coordinates of the jib tip position P17a may be detected directly. [Example A1b-1] The coordinates of the jib tip position P17a may be detected by, for example, image recognition of a camera image. For example, the coordinates of the jib tip position P17a may be detected by image recognition of a camera image including the jib tip 17a. Furthermore, for example, the coordinates of the jib tip position P17a may be detected by image recognition of a camera image including a mark (such as an AR (Augmented Reality) marker) attached to the jib tip 17a. [Example A1b-2] The coordinates of the jib tip position P17a may be detected by a positioning system using light, radio waves, or the like. For example, the positioning system may be a satellite positioning system, such as a GNSS (global navigation satellite system). For example, the positioning system may be a system using a (terrestrial) transmitter and receiver without using satellites. For example, the positioning system may be one using a total station.

[0037] [Example A2] The jib tip position information acquired by the jib tip position information acquisition unit 41 (see FIG. 2) may include information correlated with the jib tip position P17a. The jib tip position information acquisition unit 41 may acquire information correlated with the jib tip position P17a without acquiring (e.g., calculating or detecting) the coordinates of the jib tip position P17a. The "information correlated with the jib tip position P17a" may be information on the operation of the attachment A by the attachment operation unit 33 (see FIG. 2). The "information correlated with the jib tip position P17a" may include information on the content of the operation by the attachment operation unit 33, or may include information on the amount of operation by the attachment operation unit 33. For example, the "information correlated with the jib tip position P17a" may include information on the hoisting operation of the boom 13 and the hoisting operation of the jib 17, or may include information on the rotation operation of the upper rotating body 11b.

[0038] The jib tip ground contact state acquisition unit 43 (attachment tip ground contact state acquisition unit) (see FIG. 2) acquires the ground contact state of the jib tip 17a. More specifically, the jib tip ground contact state acquisition unit 43 acquires information (jib tip ground contact state determination information) for determining whether the jib tip 17a is in a ground contact state (see FIG. 7). The jib tip ground contact state determination information may include information on the height of the jib tip 17a from the ground G. In this case, the jib tip ground contact state acquisition unit 43 may be the jib tip position information acquisition unit 41. The jib tip ground contact state determination information may include information on the detection result of a contact sensor (e.g., a limit switch). This contact sensor is, for example, provided on the jib tip 17a and switches an output signal (e.g., on / off) depending on whether or not the jib tip 17a is in contact with the ground G. The jib tip ground contact state determination information may include a detection value of the load acting on the jib tip roller 17c. The jib tip ground contact state determination information may include a detected value of the load acting on the jib hoisting device 19 (specifically, the jib guy line 19b, the strut guy line 19c, or the jib hoisting rope 19d).

[0039] The information acquisition unit 40 (see FIG. 2 ) may acquire information related to the operation of the crane apparatus 1 that is different from the above-described information (jib tip position information and jib tip ground contact state determination information). The information acquisition unit 40 may also acquire loads acting on the guy lines and ropes. The information acquisition unit 40 may also acquire loads related to the boom hoisting device 15, such as the load (tension) acting on at least one of the boom guy line 15d and the boom hoist rope 15e. The information acquisition unit 40 may also acquire loads related to the jib hoisting device 19, such as the load acting on at least one of the strut guy line 19c, the jib hoist rope 19d, and the jib guy line 19b. The information acquisition unit 40 may also acquire information related to the load acting on the hoisting rope 25. The information acquisition unit 40 may also acquire at least one of the length of the hoisting rope 25 wound around the hoisting winch 27 and the length of the hoisting rope 25 unwound from the hoisting winch 27. In this case, for example, the position of the hoisting rope 25 being let out from the hoisting winch 27 (for example, from which layer and row of the hoisting winch 27 the hoisting rope 25 is being let out) may be detected by image recognition of the camera image of the hoisting winch 27.

[0040] The information acquisition unit 40 (see FIG. 2) may acquire (use) information held by an overload prevention device (moment limiter) that is normally provided on the crane 10. The information acquisition unit 40 may be included in the overload prevention device. Typically, the overload prevention device holds information on the above-mentioned "specifications of attachment A," boom hoisting angle θ13, jib offset angle θ17, the above-mentioned "load related to the boom hoisting device 15," and the above-mentioned "load related to the jib hoisting device 19." The information acquisition unit 40 may acquire (use) at least a portion of this information. The information acquisition unit 40 may acquire jib tip position information from at least a portion of this information.

[0041] The controller 50 (see FIG. 2) is a computer that inputs and outputs information and performs calculations, etc. For example, commands output by the attachment operating unit 33 and information acquired by the information acquiring unit 40 are input to the controller 50. The controller 50 controls the operation of the crane 10. The controller 50 controls the operation of the crane 10 by outputting signals to the drive control unit 31 (see FIG. 2). The controller 50 may be mounted on the crane 10, may be provided outside the crane 10, or may be provided both inside and outside the crane 10. The controller 50 includes an attachment control unit 51 (see FIG. 2) and a hoisting winch control unit 53 (see FIG. 2).

[0042] The attachment control unit 51 (see Figure 2) controls the operation of the attachment A. The attachment control unit 51 includes a boom hoisting control unit 51a (see Figure 2) and a jib hoisting control unit 51b (see Figure 2). The boom hoisting control unit 51a controls the raising and lowering of the boom 13, specifically controlling the operation of the boom hoisting winch 15w. The jib hoisting control unit 51b controls the raising and lowering of the jib 17, specifically controlling the operation of the jib hoisting winch 19w.

[0043] The hoisting winch control section 53 (see FIG. 2) controls the operation of the hoisting winch 27. The hoisting winch control section 53 controls the winding and unwinding of the hoisting rope 25 by the hoisting winch 27. When the hook 23 is suspended from the jib tip 17a, the hoisting winch control section 53 controls the winding and lowering of the hook 23.

[0044] As shown in FIG. 3, the hook holder 60 has the hook 23 placed thereon and supports (holds) the hook 23. The hook holder 60 is movable on the ground G and can transport the hook 23. The hook holder 60 may be a vehicle (cart) that can travel on the ground G using wheels, crawlers, or the like, or may be a vehicle that can travel while sliding on the ground G (gliding on the ground G). Only one hook holder 60 may be provided, or multiple hook holders 60 may be provided. The hook holder 60 includes a hook holder main body 61, a hook lowering portion 63, a hook movement restricting portion 65 (see FIG. 4), and a movement portion 67.

[0045] Hook holder main body 61 is the portion on which hook 23 is placed. For example, hook holder main body 61 may be in the shape of a container without a lid, a plate, a frame, a mesh, etc. The bottom of hook holder main body 61 may be inclined relative to the horizontal direction as in the example shown in Figure 3, or it may not be inclined relative to the horizontal direction.

[0046] The hook lowering portion 63 lowers the hook 23 when the hook 23 is lowered toward the hook holder 60. The reason for providing the hook lowering portion 63 is as follows. When the hook 23 suspended by the hoisting rope 25 is long in the vertical direction Z (longitudinal), if the hook 23 is placed on the hook holder 60 with its longitudinal direction aligned with the vertical direction Z, the hook 23 is likely to fall over and is unstable. Therefore, when the hook 23 is brought into contact with the hook lowering portion 63 during descent, the longitudinal direction of the hook 23 is lowered in a direction intersecting the vertical direction Z (for example, a direction inclined with respect to the vertical direction Z). In this state, the hook 23 is placed on the hook holder 60 (see FIG. 4 ). Therefore, the hook 23 can be placed on the hook holder 60 in a stable state. The hook lowering portion 63 is intended to lower the hook 23 so that the hook 23 can be placed on the hook holder 60 in a stable manner.

[0047] The hook lowering portion 63 is provided on the hook holder main body 61. For example, the hook lowering portion 63 is arranged so that when the hook 23 is lowered, the hook-shaped portion 23b of the hook 23 does not come into contact with the bottom of the hook holder main body 61, but the hook lowering portion 63 can come into contact with the hook main body 23a. For example, the hook lowering portion 63 is a protrusion protruding from a part of the hook holder main body 61 (e.g., the bottom or side). For example, the hook lowering portion 63 may be a part of the container-shaped hook holder main body 61 (e.g., the side). Note that if the hook 23 is vertically long, the hook 23 does not need to be placed on the hook holder 60 in a laid-down state. Also, if the hook 23 is horizontally long, the hook 23 may be placed on the hook holder 60 in a laid-down state.

[0048] As shown in FIG. 4, the hook movement limiting portion 65 limits movement of the hook 23 relative to the hook holder main body 61. The hook movement limiting portion 65 may limit movement of the hook 23 relative to the hook holder main body 61 in the front-rear direction X, in the lateral direction Y, or upward Z1. The hook movement limiting portion 65 prevents the hook 23 from separating from the hook holder 60 (e.g., the hook 23 from falling) when the hoisting rope 25 is wound (described later) with the hook 23 placed on the hook holder 60. For example, the hook movement limiting portion 65 restrains the hook 23 to the hook holder main body 61. The hook movement limiting portion 65 is attached to the hook holder main body 61 and the hook 23. As shown in FIG. 6, the hook movement limiting portion 65 may be attached to the hook main body 23a (e.g., may be wrapped around the waist) or may be attached to the hook-shaped portion 23b. For example, the hook movement limiting portion 65 may include a string-like member, and more specifically, may include, for example, a rope, a belt, or the like. This string-like member may be made of resin or fiber. The hook movement limiting portion 65 may include a device (e.g., one having a ratchet mechanism) that applies tension to the string-like member and maintains the tension. The hook movement limiting portion 65 may include something other than a string-like member (e.g., a fastening member) that can fix the hook 23 to the hook holder main body 61. The hook movement limiting portion 65 may include only one member (see FIG. 4) or multiple members (see FIG. 6).

[0049] The moving unit 67 enables the hook holder 60 to move on the ground G. The moving unit 67 may include members (wheels, crawlers, etc.) that enable the hook holder 60 to travel on the ground G. The moving unit 67 may include members (plates, etc.) that enable the hook holder 60 to move (slide) so as to glide on the ground G. The moving unit 67 is preferably configured to be switchable between a state in which it is freely movable relative to the ground G (non-brake state) and a state in which its movement relative to the ground G is restricted (brake state (e.g., travel-lock state)). As will be described later, the hook holder 60 is movable by the tension of the hoisting rope 25, and therefore the moving unit 67 does not need to be equipped with a power source (motor, etc.) for self-propulsion.

[0050] (Activation) The crane apparatus 1 shown in FIG. 1 is configured to operate as follows.

[0051] (Attachment A lowering operation) In the crane apparatus 1, an attachment A lowering operation is performed. The attachment A lowering operation is an operation in which the attachment A is lowered from the working posture (see FIG. 1) to the ground G (ground) (see FIGS. 1, 3 to 8). The attachment A lowering operation may be performed when the crane 10 is disassembled, or may be performed at a time other than when the crane 10 is disassembled. In the attachment A lowering operation in this embodiment, the attachment A is changed from the working posture (see FIG. 1) to the hoisting posture shown in FIG. 8. The hoisting posture is a posture in which the jib 17 is positioned on the front side X1 of the boom 13 in the lowered state. An example of the reason why the attachment A is placed in the hoisting posture is as follows. If the length of the jib 17 shown in FIG. 1 is equal to or less than the length of the boom 13, the jib 17 can be stored in the boom 13. Specifically, for example, it is possible to position the jib 17 directly below the boom 13 in the lowered state (to place the jib 17 in the hoisting posture). On the other hand, if the jib 17 is longer than the boom 13, the jib 17 cannot be stored on the boom 13. Therefore, the attachment A is placed in the outboard position (see FIG. 8). Also, even if the length of the jib 17 is equal to or shorter than the length of the boom 13, the attachment A may be placed in the outboard position.

[0052] The procedure for the attachment A lowering operation (see FIG. 9) is outlined as follows. Below, steps S11 to S75 will be described with reference to FIG. 9. When the crane 10 is in the working posture, the boom 13 and the jib 17 are lowered (lowered), and as shown in FIG. 3, the attachment A is changed to a generally L-shape when viewed from the lateral direction Y (step S11). The hook 23 is lowered, and the hook 23 is placed on the hook holder 60 (steps S31 and S33). As shown in FIG. 4, the boom 13 is lowered, and the jib tip 17a is lowered (moved to the lower side Z2), and as shown in FIG. 7, the jib tip 17a touches the ground (steps S51 to S56). As the boom 13 is further lowered, the jib tip 17a is moved forward (moved to the front side X1) while touching the ground (on the ground) (step S71), as shown in FIG. 8. Then, when the tip of the boom 13 or the base end of the jib 17 touches the ground, the entire attachment A touches the ground (is lowered to the ground) (step S75). The hook 23 is detached from the jib tip 17a at various times. Specific examples of the procedure for lowering the attachment A are as follows. Note that the procedure for lowering the attachment A may be modified in various ways.

[0053] (Boom 13 lowered before hook 23 lowered) When the crane 10 is in the working posture as shown in FIG. 1, the boom 13 is lowered as shown in FIG. 3, reducing the boom hoist angle θ13. At this time, for example, the boom hoist angle θ13 may be set to the minimum boom hoist angle θ13 (minimum working angle) among the boom hoist angles θ13 that can be set when the crane 10 is in the working posture, or to approximately the minimum working angle. [Example of Manual Operation] For example, the operator of the crane 10 manually operates the attachment operating unit 33 shown in FIG. 2. Based on the operation of the attachment operating unit 33, the drive control unit 31 activates the boom hoist winch 15w shown in FIG. 1. The boom hoist winch 15w may then pay out the boom hoist rope 15e, thereby lowering the boom 13. [Example of Automatic Operation] Alternatively, the attachment operating unit 33 (e.g., the attachment control unit 51) shown in FIG. 2 may automatically control the drive control unit 31. The drive control unit 31 may then operate the boom hoisting winch 15w shown in Figure 1 to lower the boom 13. In this way, unless otherwise specified, the operations related to the crane apparatus 1 may be performed manually or automatically, and the same applies to the operations described below.

[0054] (Lowering the jib 17 before lowering the hook 23 (step S11)) When the crane 10 is in the working posture, the jib 17 is lowered and the jib offset angle θ17 is increased as shown in FIG. 3 (step S11). The reason for lowering the jib 17 is, for example, as follows: The longer the jib 17, the greater the mass of the jib 17. If the boom 13 is lowered until the jib tip 17a touches the ground while the jib offset angle θ17 remains the same angle (i.e., a small angle) as in the working posture (see FIG. 1), the center of gravity of the attachment A will move significantly toward the front X1. If the center of gravity of the entire crane 10 is located further forward X1 than the tipping fulcrum of the crane 10 (specifically, for example, the front X1 end of the lower body 11a), the crane 10 will tip over, or the boom 13 will automatically stop due to the function of the overload prevention device. Therefore, it is important to move the center of gravity of the attachment A as close as possible to the crane body 11 (rear side X2) so that the center of gravity of the entire crane 10 is as far rearward as possible from the tipping fulcrum (to ensure a margin of stability for the crane 10). Specifically, for example, the jib offset angle θ17 is increased by lowering the jib 17. For example, the attachment A is made substantially L-shaped when viewed from the lateral direction Y.

[0055] (Placing the hook holder 60 directly below the hook 23 (steps S21 and S23)) The hook holder 60 is positioned directly below the hook 23 (steps S21, S23). For example, the hook holder 60 is manually moved to a position directly below the hook 23 (step S21) by an operator. The hook holder 60 is positioned at a position directly below the hook 23 (step S23) and stops relative to the ground G. For example, it is preferable that the hook holder 60 is in a state (braked state, stopped state) in which movement relative to the ground G is restricted when it is positioned directly below the hook 23.

[0056] (Lowering of the hook 23 (step S31)) With the attachment A in a generally L-shaped state when viewed from the lateral direction Y, the hook 23 is lowered (step S31), and the hook 23 is placed on the hook holder 60 (step S33). More specifically, the hoisting winch 27 pays out the hoisting rope 25. As a result, the hook 23 is lowered, and the hook 23 is placed on the hook holder 60 (more specifically, the hook holder main body 61). While the hook 23 is being lowered, the hook holder 60 remains stationary relative to the ground G (step S31).

[0057] The hook 23 is placed on the hook holder 60 for the following reason, for example: The hook 23 is a heavy load that is located at a position forward X1 away from the crane body 11. Therefore, in order to position the center of gravity of the entire crane 10 as far rearward X2 as possible from the tipping fulcrum (to ensure the stability of the crane 10), the hook 23 is lowered and placed on the hook holder 60 (supported from the underside Z2). Furthermore, if the jib tip 17a moves (described below) while the hook 23 is in a state where it is in direct contact with the ground G, the hook 23 may be dragged by the ground G, which could result in damage to the hook 23. Therefore, in order to prevent damage to the hook 23, the hook 23 is placed on the hook holder 60. Furthermore, when the hook 23 is in a state where it is in direct contact with the ground G, the hoisting rope 25 may come into contact with the ground. If the jib tip 17a moves while the hoisting rope 25 is in contact with the ground, the hoisting rope 25 may be dragged on the ground G, possibly resulting in damage to the hoisting rope 25 (details will be described later). Therefore, in order to prevent damage to the hoisting rope 25, the hook 23 is placed on a hook holder 60.

[0058] (Operation when the hook 23 is placed on the hook holder 60 (steps S33, S35)) The hook 23 is lowered and placed on the hook holder 60 (step S33). At this time, the hoisting winch 27 stops unwinding the hoisting rope 25 (step S35). This prevents the hoisting rope 25 from being unwound excessively, and prevents the hoisting rope 25 from touching the ground.

[0059] When the hook holder 60 includes the hook lowering portion 63, the hook 23 is tilted and lowered by being lowered while in contact with the hook lowering portion 63. At this time, the longitudinal direction of the hook 23 changes from the vertical direction Z to a direction intersecting the vertical direction Z (to the front side X1 in FIG. 3). Then, the hook 23 is placed on the hook holder main body 61 in the lowered state.

[0060] 6, when hook 23 is placed on hook holder 60 (more specifically, hook holder main body 61), movement of hook 23 relative to hook holder main body 61 is restricted (e.g., restrained) by hook movement restricting part 65. For example, hook movement restricting part 65 is manually attached to hook 23 and hook holder main body 61 by an operator.

[0061] For example, when the hook 23 shown in Fig. 3 is placed on the hook holder 60, the jib tip position information acquisition unit 41 (see Fig. 2) acquires and stores jib tip position information. For example, the jib tip position information acquisition unit 41 may acquire and store the height (lifting height) from the ground G to the jib tip 17a.

[0062] Before the jib tip 17a is lowered in step S51 below, the hook holder 60 may be placed in the contact avoidance position (step S41) (details will be described later).

[0063] (Lowering of the jib tip 17a (step S51)) As shown in FIG. 4, with the hook 23 placed on the hook holder 60, the jib tip 17a is lowered (jib tip lowering step, attachment tip lowering step). Specifically, for example, the boom 13 is lowered and the boom hoist angle θ13 is reduced. At this time, for example, the jib offset angle θ17 is kept constant (or may be changed). Note that if the boom 13 and jib 17 are both short, the crane 10 will have a margin of stability even if the jib offset angle θ17 is not kept constant. In this case, the jib 17 may be hoisted (the jib offset angle θ17 may be changed) while the boom hoist angle θ13 is being reduced.

[0064] When the jib tip 17a is descending, the jib tip position information acquisition unit 41 (see FIG. 2) acquires jib tip position information (jib tip position information acquisition step). Specifically, for example, the jib tip position information acquisition unit 41 may acquire the position (height, coordinates) of the jib tip 17a in the up-down direction Z. The jib tip position information acquisition unit 41 may acquire the position (coordinates) of the jib tip 17a in the fore-and-aft direction X. The jib tip position information acquisition unit 41 may acquire information on the operation of the attachment operation unit 33 (see FIG. 2).

[0065] When the jib tip 17a is being lowered, the information acquisition unit 40 (see FIG. 2) may acquire the length of the hoisting rope 25 being reeled out from the hoisting winch 27. Based on this length, the controller 50 (see FIG. 2) may determine the condition of the hoisting rope 25 (for example, the degree of slack in the hoisting rope 25).

[0066] (Winding of the hoisting rope 25 when the jib tip 17a is lowered (step S53)) As described above, with the hook 23 placed on the hook holder 60, the jib tip 17a is lowered (the jib tip lowering step is performed). At this time, the hoisting winch control section 53 (see FIG. 2) performs jib lowering winding control to cause the hoisting winch 27 to wind up the hoisting rope 25 (performs attachment lowering winding control) (jib lowering winding step, attachment lowering winding step) (step S53). This winding up of the hoisting rope 25 is performed automatically by the hoisting winch control section 53 (see FIG. 2), not by manual operation by the operator.

[0067] The reason why the hoisting winch 27 is made to reel in the hoisting rope 25 when the jib tip 17a is lowered is as follows.

[0068] [Grounding Problems] When the jib tip 17a descends, the distance between the hook 23 and the jib tip 17a becomes shorter. Therefore, unless the hoisting winch 27 retracts the hoisting rope 25, the hoisting rope 25 may sag (hang down) between the jib tip 17a (more specifically, the point sheave 21) and the hook 23, potentially causing the hoisting rope 25 to contact the ground. For example, the hoisting rope 25 may contact the ground in a coiled state. If the hoisting rope 25 contacts the ground, the following problems may occur: The hoisting rope 25 is coated with grease for lubrication (for example, to lubricate the strand). The "strand" is made up of multiple strands (wires) twisted together. If the greased hoisting rope 25 contacts the ground, foreign matter (for example, sand, mud, etc.) will stick to the hoisting rope 25. Furthermore, if the hoisting rope 25 is dragged while it is in contact with the ground, the grease will come off the hoisting rope 25, reducing the lubrication of the hoisting rope 25. A hoisting rope 25 with at least one of foreign matter stuck to it and grease coming off may pass through a sheave or be wound up by the hoisting winch 27. This may damage the wires of the hoisting rope 25, and may even cause the wires to break. Furthermore, if the hoisting rope 25 is dragged while it is in contact with the ground G, the hoisting rope 25 may be damaged due to friction between the ground G and the hoisting rope 25, or the hoisting rope 25 getting caught on foreign matter on the ground G.

[0069] [Problem of Uneven Winding] Furthermore, if the hoisting winch 27 does not wind up the hoisting rope 25 when the jib tip 17a is lowered, the tension of the hoisting rope 25 may become too small, which may cause undue winding on the hoisting winch 27. For example, in order to prevent the above-mentioned [grounding problem] and [problem of uneven winding], the hoisting winch 27 is made to wind up the hoisting rope 25 when the jib tip 17a is lowered. Specifically, the hoisting winch control unit 53 performs hoisting control when the jib is lowered.

[0070] The timing for the hoisting winch control unit 53 (see FIG. 2) to perform the jib lowering hoisting control is when the jib tip 17a is lowered with the hook 23 mounted on the hook holder 60, i.e., when the jib tip lowering step is being performed. For example, the hoisting winch control unit 53 determines whether it is time to perform the jib lowering hoisting control based on information acquired by the information acquisition unit 40 (see FIG. 2). This "information acquired by the information acquisition unit 40" may be, for example, information detected by a sensor or the like. Specifically, for example, the "information acquired by the information acquisition unit 40" may include information on the operation of the attachment operation unit 33 (e.g., the operation of lowering the boom 13) and information on whether the hook 23 is mounted on the hook holder 60. Furthermore, for example, the "information acquired by the information acquisition unit 40" may include information indicating the operation mode of the crane 10, such as information set in the controller 50. Specifically, for example, the "information acquired by the information acquisition unit 40" may include information indicating whether or not a mode for lowering the jib tip 17a has been selected.

[0071] In the jib lowering winding control, the hoisting winch control unit 53 (see FIG. 2) causes the hoisting winch 27 to reel in the hoisting rope 25 based on the jib tip position information acquired by the jib tip position information acquisition unit 41 (see FIG. 2). For example, the hoisting winch control unit 53 (see FIG. 2) may perform the jib lowering winding control based on the position of the jib tip 17a in the up-down direction Z (e.g., the amount of descent of the jib tip 17a). For example, the hoisting winch control unit 53 may perform the jib lowering winding control based on the position of the jib tip 17a in the fore-and-aft direction X. For example, the hoisting winch control unit 53 may perform the jib lowering winding control based on the position of the jib tip 17a in the fore-and-aft direction X and the up-and-aft direction Z (a position taking into account movements in both the fore-and-aft direction X and the up-and-aft direction Z). The hoisting winch control unit 53 may perform hoisting control during jib lowering based on information correlated with the jib tip position P17a acquired by the jib tip position information acquisition unit 41 (see Figure 2) (for example, operation of the attachment operation unit 33).

[0072] The hoisting winch control unit 53 (see FIG. 2) may perform hoisting control during jib lowering so that the tension of the hoisting rope 25 is maintained within a predetermined range (within the hoisting rope predetermined tension range). More specifically, as described above, in the hoisting control during jib lowering, the hoisting winch control unit 53 causes the hoisting winch 27 to reel in the hoisting rope 25 based on the jib tip position information. As a result, the tension of the hoisting rope 25 may be maintained within the hoisting rope predetermined tension range. Note that the hoisting winch control unit 53 may perform hoisting control during jib lowering based on the tension of the hoisting rope 25 and the jib tip position information acquired by the information acquisition unit 40.

[0073] The reason why the hoisting winch 27 winds the hoisting rope 25 so that the tension of the hoisting rope 25 is maintained within a predetermined range (within the predetermined hoisting rope tension range) is as follows: If the amount of hoisting rope 25 wound is too small relative to the descent of the jib tip 17a, problems such as the hoisting rope 25 touching the ground and irregular winding on the hoisting winch 27 may occur. On the other hand, if the amount of hoisting rope 25 wound is too large relative to the descent of the jib tip 17a, the following problem may occur: If the hook 23 is fixed to the hook holder 60, the hook 23 and hook holder 60 will be lifted up by the hoisting rope 25 and raised above the ground G. If the hook 23 is not fixed to the hook holder 60, the hook 23 will be lifted up by the hoisting rope 25 and raised above the hook holder 60. When the hook 23 and other components are lifted, the center of gravity of the entire crane 10 moves to the front X1, reducing the stability margin of the crane 10. Therefore, the hoisting winch control unit 53 (see FIG. 2) controls the hoisting winch 27 to reel in the hoisting rope 25 so that the tension of the hoisting rope 25 is maintained within a predetermined range (within the predetermined hoisting rope tension range) during jib lowering hoisting control. Specifically, the hoisting winch control unit 53 performs jib lowering hoisting control so that the tension of the hoisting rope 25 is maintained so that the hoisting rope 25 does not sag and touch the ground and the hook 23 and other components are not lifted by the hoisting rope 25. The hoisting winch control unit 53 may also perform jib lowering hoisting control as follows: The hoisting winch control unit 53 calculates the position of the descending jib tip 17a based on a hook lifting height calculation, assuming that the hook 23 is in contact with the ground G. The hoisting winch control unit 53 may control the amount of hoisting rope 25 wound by the hoisting winch 27 so as to keep the length of the hoisting rope 25 constant between the hook 23, which is assumed to be in contact with the ground G, and the jib tip 17a.

[0074] (Movement of the hook holder 60 when the jib tip 17a is lowered (Step S55)) When the jib tip 17a descends, the hoisting winch control section 53 (see FIG. 2) moves the hook holder 60 to follow the movement of the jib tip 17a toward the front side X1 (step S55). More specifically, when the jib tip 17a is lowered (when the jib tip lowering step is performed), if the jib offset angle θ17 is constant, the jib tip 17a rotates about the base end of the boom 13 (the attachment portion of the boom 13 to the upper rotating body 11b). At this time, the jib tip 17a moves toward the front side X1 while moving toward the lower side Z2. If the distance in the fore-and-aft direction X from the jib tip 17a (more specifically, the point sheave 21) to the hook 23 becomes long, the hoisting rope 25 will sag, which could result in the hoisting rope 25 touching the ground. Therefore, in the hoisting control for jib lowering, the hoisting winch control unit 53 (see FIG. 2) causes the hoisting winch 27 to reel in the hoisting rope 25 so that the hook holder 60 moves (follows) as the jib tip 17a moves toward the front side X1. In the hoisting control for jib lowering, the hoisting winch control unit 53 (see FIG. 2) causes the hoisting winch 27 to reel in the hoisting rope 25 so that the tension of the hoisting rope 25 is maintained so that the hook holder 60 moves toward the front side X1. As a result, the hook 23 and hook holder 60 are pulled toward the front side X1 by the hoisting rope 25 and move toward the front side X1. At this time, the hook 23 and hook holder 60 move to a position X2 behind the jib tip 17a (a position delayed from the jib tip 17a). At this time, the hook holder 60 moves due to the tension of the hoisting rope 25, so the hook holder 60 does not need to be equipped with power.

[0075] In the hoisting control during jib lowering, the hoisting winch control unit 53 preferably controls the hoisting winch 27 so that the distance from the jib tip 17a to the hook 23 matches (is equal to or approximately equal to) the distance from the jib tip 17a to the hook holder main body 61. At this time, the hoisting winch control unit 53 preferably controls the hoisting winch 27 so that the hook 23 and the hook holder main body 61 move together (together, integrally, or approximately integrally). The hoisting winch control unit 53 preferably controls the hoisting winch 27 so as to suppress movement of the hook 23 in the front-to-rear direction X relative to the hook holder main body 61. When the hook 23 and the hook holder main body 61 move together, movement of the hook 23 upward Z1 relative to the hook holder main body 61 is suppressed. Therefore, the hook movement limiting unit 65 does not need to (may) restrict (for example, by fastening) movement of the hook 23 in the up-down direction Z relative to the hook holder main body 61.

[0076] (Interlocking of the operation for lowering the jib tip 17a and the hoisting control during jib lowering) As described above, the operation of lowering the jib tip 17a may be manual or automatic. Here, a case where the operation of lowering the jib tip 17a is manual will be described. The hoisting winch control unit 53 (see FIG. 2) controls the hoisting of the jib during lowering in accordance with the operation (manual operation) of the attachment operating unit 33 (see FIG. 2), which performs the operation to lower the jib tip 17a (e.g., the operation to lower the boom 13). For example, if the operation to lower the jib tip 17a is the operation of a single lever (single-lever operation), the operation to lower the boom 13 and the operation to reel in the hoisting rope 25 can be performed (linked) by the single-lever operation. Note that, as described above, if the boom 13 and the jib 17 are each short, the jib 17 may be raised and lowered while the boom 13 is being lowered. In this case, the operation to raise and lower the jib 17 needs to be performed by a lever operation separate from the operation to lower the boom 13, rather than by a single-lever operation. Even in this case, the hoisting winch control section 53 acquires the position of the jib tip 17a from the boom hoisting angle θ13 and the jib offset angle θ17, and performs hoisting control when the jib is lowered based on the acquired position. Therefore, the hoisting rope 25 can be automatically wound in accordance with the operation of the boom 13 for lowering the jib tip 17a and the operation of the jib 17 (there is no need for an operation performed solely for winding the hoisting rope 25).

[0077] (Stopping winding of the hoisting rope 25 when the jib tip 17a descends (step S56)) The hoisting winch control section 53 stops winding of the hoisting rope 25 by the hoisting winch 27 when the height of the jib tip 17a from the ground G reaches a predetermined height (winding stop height) (step S56). Stopping the winding of the hoisting rope 25 by the hoisting winch 27 prevents the hook 23 from being lifted by the hoisting rope 25. As a result, the center of gravity of the entire crane 10 is prevented from moving forward X1. Also, the hook 23 is prevented from contacting the jib tip 17a. The winding stop height may be the height of the ground G (the height of the jib tip 17a when it touches the ground). The winding stop height may be a height Z1 above the ground G (the height of the jib tip 17a before it touches the ground). For example, when the jib tip position information acquisition unit 41 (see FIG. 2) acquires the height of the jib tip 17a, the winding stop height may be the lowest height (or a height close to that height) of the heights of the jib tip 17a that can be acquired by the jib tip position information acquisition unit 41. In this case, the hoisting winch control unit 53 is prevented from performing hoisting control during jib lowering when the jib tip 17a is positioned at a height that cannot be acquired by the jib tip position information acquisition unit 41 (based on jib tip position information that may be inaccurate).

[0078] (Grounding of the jib tip 17a (step S57)) When the jib tip 17a descends, as shown in FIG. 7, the jib tip 17a (for example, the jib tip roller 17c) comes into contact with the ground (step S57).

[0079] (Contact avoidance position) As shown in Fig. 4, it is preferable that contact between the jib tip portion 17a and the hook holder 60 can be suppressed when the jib tip portion 17a descends and reaches the vicinity of the ground G or when the jib tip portion 17a touches the ground. For example, it is preferable that the hook 23 and the hook holder 60 are shifted relative to the jib tip portion 17a, as shown in Fig. 5, before the jib tip portion 17a descends to the vicinity of the ground G. More specifically, the hook 23 and the hook holder 60 may be placed in a "contact avoidance position" (step S41).

[0080] For example, the contact avoidance position is a position that is predicted to be around the jib tip 17a when the jib tip 17a touches the ground. More specifically, the contact avoidance position is the following position. Assume that the jib tip 17a is lowered and touches the ground from a state in which the jib tip 17a is positioned above the hook 23 and the hook holder 60 (see, for example, FIG. 4). The contact avoidance position is a position around the jib tip 17a (a position that does not overlap with the jib tip 17a) when it is assumed that the jib tip 17a touches the ground in this manner. The contact avoidance position is a position of the hook 23 and the hook holder 60 at which it is predicted that the hook 23 and the hook holder 60 will not come into contact with the jib tip 17a when the jib tip 17a touches the ground. For example, the contact avoidance position is a position that is predicted to be a predetermined distance away from the jib tip 17a when the jib tip 17a touches the ground. Specifically, for example, the contact avoidance position may include a position (area) that is predicted to be located outside the jib tip 17a in the lateral direction Y (outside the jib width direction Yo (outside the attachment width direction)) when the jib tip 17a touches the ground. More specifically, the contact avoidance position may include a position outside the jib width direction Yo of a portion of the jib tip 17a that is predicted to be positioned at the same height as the hook holder 60 (for example, the jib tip roller 17c, etc.) when the jib tip 17a touches the ground. As shown in FIGS. 6 and 7 , the contact avoidance position may include a position that is predicted to be located outside the jib tip 17a in the fore-and-aft direction X when the jib tip 17a touches the ground.

[0081] For example, the contact avoidance position is preferably set to a position that is predicted to be near the jib tip 17a when the jib tip 17a touches the ground. More specifically, if the distance between the jib tip 17a and the hook holder 60 is too large when the jib tip 17a touches the ground, the following problem may occur. In this case, the weight of the hoisting ropes 25 may cause the hook holder 60 to move in a direction approaching the jib tip 17a, causing the hoisting ropes 25 to sag and touch the ground. Therefore, the contact avoidance position is preferably set to a position that is predicted to be near the jib tip 17a when the jib tip 17a touches the ground ("near enough" to prevent the problem of the hoisting ropes 25 touching the ground).

[0082] (Timing of placement in contact avoidance position) The timing at which the hook 23 and hook holder 60 shown in Fig. 5 are placed in the contact avoidance position (the timing at which step S41 is performed) is before the jib tip 17a is lowered to the vicinity of the ground surface G. The timing at which the hook 23 and hook holder 60 are placed in the contact avoidance position may be before the jib tip lowering step is performed (before step S51) or when the jib tip lowering step is performed (after step S51).

[0083] Furthermore, the hook 23 and the hook holder 60 may be positioned in the contact avoidance position after the jib tip 17a has touched the ground. Specifically, as shown in FIG. 7, when the jib tip 17a descends and touches the ground, there are cases where the hook holder 60 and the jib tip 17a do not interfere with each other (when a distance that does not cause interference is maintained). After the jib tip 17a touches the ground, when the hook holder 60 is moved to follow the jib tip 17a, there is a possibility that the jib tip 17a and the hook holder 60 will interfere with each other. In such cases, the hook 23 and the hook holder 60 may be positioned in the contact avoidance position after the jib tip 17a touches the ground and before the jib tip 17a and the hook holder 60 interfere with each other (see FIG. 6).

[0084] (How to position the device to avoid contact) The hook 23 and hook holder 60 shown in FIG. 3 are disposed from a state in which they are disposed directly below the jib tip 17a to a contact avoidance position, for example, as follows. The hook 23 and hook holder 60 may be disposed at the contact avoidance position by moving the jib 17. Specifically, for example, the hook 23 and hook holder 60 may be shifted in the lateral direction Y with respect to the jib tip 17a by rotating the upper rotating body 11b relative to the lower main body 11a, and disposed at the contact avoidance position. Furthermore, for example, the hook 23 and hook holder 60 may be shifted in the fore-and-aft direction X with respect to the jib tip 17a by changing the jib offset angle θ17, and disposed at the contact avoidance position. Furthermore, the hook 23 and hook holder 60 may be disposed at the contact avoidance position by moving the hook holder 60 relative to the ground G. In this case, the hook holder 60 may be moved in the lateral direction Y with respect to the ground G, or may be moved in the fore-and-aft direction X (e.g., rearward X2) with respect to the ground G.

[0085] As described above, when the jib tip 17a descends (when hoisting control is performed during jib lowering), the hook holder 60 may move following the jib tip 17a (step S55). At this time, it is preferable that the hook holder 60 move following the jib tip 17a so that the hook 23 and the hook holder 60 remain positioned in the contact avoidance position. For example, when the jib tip 17a descends, the hook holder 60 moves to a position outside the jib tip 17a in the lateral direction Y (outside the jib width direction Yo). Also, for example, when the jib tip 17a descends, the hook holder 60 moves to a position outside the fore-aft direction X of the position of the jib tip 17a when it is assumed that the jib tip 17a has touched the ground.

[0086] Specific examples of methods for moving the hook holder 60 to a position Yo on the outside in the jib width direction of the jib tip 17a are as follows. [Example B1] For example, the moving unit 67 may be steered so that the hook holder 60 shown in FIG. 5 does not approach the jib tip 17a. For example, the moving unit 67 may be steered so that the hook holder 60 moves away from the jib tip 17a to the outside in the jib width direction Yo. For example, the moving unit 67 may be steered so that the distance in the lateral direction Y from the hook holder 60 to the jib tip 17a is maintained. [Example B2] If the moving unit 67 has wheels on both sides in the lateral direction Y, the diameter of the wheel on the side closer to the jib tip 17a (inner side) may be larger than the diameter of the wheel on the side farther from the jib tip 17a (outer side). [Example B3] The center of gravity of the entire hook holder 60 and the hook 23 may be located farther from the jib tip 17a than the center of the hook holder 60 in the lateral direction Y (the center of gravity may be offset). [Example B3-1] To this end, the portion of the hook holder main body 61 on which the hook 23 is placed (e.g., the bottom) may be inclined so that it becomes lower the farther from the jib tip 17a. In this case, the hook 23 is more likely to be placed on the side of the hook holder 60 farther from the jib tip 17a. [Example B3-2] Furthermore, the position on the hook holder main body 61 where the hook 23 can be placed may be limited to a position on the hook holder 60 farther from the jib tip 17a. In the above [Example B3-1] and [Example B3-2], the weight of the hook 23 can cause the center of gravity of the entire hook holder 60 and the hook 23 to be located farther from the jib tip 17a than the center of the hook holder 60 in the lateral direction Y. [Example B3-3] The center of gravity of the hook holder 60 may be positioned farther from the jib tip 17a of the hook holder 60 than the center of the hook holder 60 in the lateral direction Y (the center of gravity may be eccentric).

[0087] Note that when the hook 23 is placed on the hook holder 60 (step S23), the positions of the hook 23 and the hook holder 60 may be in the contact avoidance position (step S41 may not be performed). For example, as shown in Fig. 4, in the jib tip lowering step, the jib tip 17a may move to the front side X1 while descending. In this case, even if the hook 23 and the hook holder 60 remain in the position in step S23, when the jib tip 17a descends to the vicinity of the ground G, it may be possible to ensure a distance in the fore-and-aft direction X between the hook holder 60 and the jib tip 17a.

[0088] (Operation of the jib tip 17a when and after it touches down) As shown in Fig. 7, when the jib tip 17a touches the ground, the lowering of the boom 13 may be stopped, or the lowering of the boom 13 may be continued. For example, the lowering of the boom 13 may be stopped when the jib tip 17a touches the ground, and an operation (described later) of removing the hook 23 from the hoisting rope 25 may be performed. For example, the lowering of the boom 13 may be stopped when the jib tip 17a touches the ground, and an operator may check the states of the jib tip 17a, the hook 23, the hook holder 60, and the like. At this time, the relative position of the hook holder 60 with respect to the jib tip 17a may be set to a followable position (described later) (step S61).

[0089] (Forward movement of the jib tip 17a on the ground G (steps S71, S73)) After the jib tip 17a touches the ground (after the jib tip 17a touches the ground due to the jib tip lowering step), the jib tip 17a is advanced as shown in FIG. 8 (step S71). More specifically, with the jib tip 17a in a state of touching the ground, the boom 13 is lowered (jib touchdown boom lowering step). Then, the jib 17 is pushed forward X1 by the boom 13. Then, while in a state of touching the ground, the jib tip 17a slides and moves forward X1 (advances). Specifically, for example, the jib tip roller 17c rotates (rolls) relative to the jib main body 17b while in contact with the ground G. Hereinafter, the advancement of the jib tip 17a on the ground G will also be simply referred to as "advancement." When the jib tip 17a advances, the jib offset angle θ17 shown in FIG. 7 decreases. Then, when viewed from the lateral direction Y, the attachment A changes from a substantially L-shape (see FIG. 7) to a substantially linear shape (see FIG. 8).

[0090] If the hook 23 is not detached from the hoisting ropes 25 when the jib tip 17a moves forward, the hook 23 and hook holder 60 move following the movement of the jib tip 17a (jib grounding hook holder movement step) (step S73). More specifically, the hook 23 and hook holder 60 are pulled toward the front side X1 by the hoisting ropes 25 and move toward the front side X1. At this time, the hook 23 and hook holder 60 move to a position X2 behind the jib tip 17a moving toward the front side X1 (a position delayed from the jib tip 17a). At this time, the hook holder 60 moves due to the tension of the hoisting ropes 25 (including the case where the tension of the jib hoist ropes 19d is transmitted to the hoisting ropes 25 via the jib tip 17a), so the hook holder 60 does not need to be equipped with power.

[0091] (Winding the jib hoisting rope 19d when the jib tip 17a moves forward) When the jib tip 17a moves forward, the jib hoist winch 19w reels in the jib hoist rope 19d. If the jib hoist rope 19d is not reeled in when the jib tip 17a moves forward, the following problem can occur. In this case, the jib hoist rope 19d may slacken, causing the jib hoist rope 19d to become irregularly wound around the jib hoist winch 19w. There is also a risk that the front strut 19a2 may interfere with the jib 17. On the other hand, if the jib hoist rope 19d is reeled in too much, the jib tip 17a will lift off the ground G, the center of gravity of the entire crane 10 will shift forward X1, and the stability margin of the crane 10 will decrease.

[0092] The following describes a case where the boom hoist rope 15e is automatically wound. For example, the jib hoist control unit 51b (see FIG. 2) controls the jib hoist winch 19w so that the jib hoist rope 19d (or strut guy line 19c) is subjected to tension (tension within the specified jib hoist rope tension range) that will prevent these problems. Specifically, the jib hoist control unit 51b (see FIG. 2) controls the jib hoist winch 19w to wind the jib hoist rope 19d in accordance with the tension on the jib hoist rope 19d (or strut guy line 19c) acquired by the information acquisition unit 40 (see FIG. 2). At this time, the tension on the jib hoist rope 19d is as follows: When the jib tip end 17a moves forward, the jib tip end 17a touches the ground and the hook 23 is placed on the hook holder 60, or the hook 23 is released from the jib tip end 17a. In this state, the load due to the weight of the jib 17 and the weight of the hook 23 is not applied to the jib hoist rope 19d. In this state, the load applied to the jib hoist rope 19d is the weight of the strut 19a and the weight of the jib guy line 19b. Note that the weight of the strut 19a may be subtracted (cancelled) from the detected value of the tension of the jib hoist rope 19d. Only the weight of the jib guy line 19b may be used as the detected value of the tension of the jib hoist rope 19d.

[0093] In this way, as the jib tip 17a moves forward, the jib hoist winch 19w reels in the jib hoist rope 19d. As the jib hoist rope 19d is reeled in, the front strut 19a2 rotates around its base end (the end on the boom 13 side) in a direction toward the rear strut 19a1. The rotation of the front strut 19a2 toward the rear strut 19a1 is then restricted by a strut backstop (not shown), rendering the front strut 19a2 unable to rotate. When the front strut 19a2 is no longer able to rotate, the jib hoist control unit 51b (see FIG. 2) causes the jib hoist winch 19w to stop reeling in the jib hoist rope 19d. If a strut backstop is not provided, the jib hoist control unit 51b will cause the jib hoist winch 19w to stop winding the jib hoist rope 19d when the front strut 19a2 reaches a predetermined position. This "position of the front strut 19a2" may be detected by a sensor (such as a limit switch) that detects the rotation angle of the front strut 19a2 relative to the boom 13. This sensor may be provided, for example, in front of or behind the front strut 19a2 (in front of or behind the direction in which the front strut 19a2 is raised or lowered). For example, if this sensor is a limit switch, the jib hoist control unit 51b will cause the jib hoist winch 19w to stop winding the jib hoist rope 19d when the front strut 19a2 acts on (contacts) the limit switch.

[0094] After the jib hoist control section 51b (see Figure 2) causes the jib hoist winch 19w to stop winding the jib hoist rope 19d, the boom hoist winch 15w further pays out the boom hoist rope 15e, further lowering the boom 13. This further reduces the jib offset angle θ17, causing the jib guy line 19b to sag (loosen), as shown in Figure 8.

[0095] (The forward movement of the jib tip 17a is linked to the boom hoisting winch 15w) The operation of lowering the boom 13 when the jib tip 17a is moving forward (operation of the attachment operating unit 33) and the operation of having the jib hoist winch 19w wind up the jib hoist rope 19d may each be performed manually or automatically. Here, a case where the operation of lowering the boom 13 to move the jib tip 17a forward is performed manually will be described. The jib hoist control unit 51b (see FIG. 2) may cause the jib hoist winch 19w to wind up the jib hoist rope 19d in response to the operation of moving the jib tip 17a forward (specifically, the operation of lowering the boom 13). For example, if the operation to move the jib tip 17a forward is performed by operating a single lever (single-lever operation), the operation of lowering the boom 13 and the operation of winding up the jib hoist rope 19d can be performed (linked) by operating the single lever.

[0096] (Grounding of the boom 13, etc. (Step S75)) When the boom 13 is lowered and the jib tip 17a moves forward, the tip of the boom 13 or the base end of the jib 17 touches the ground. At this time, the tip of the boom 13 or the base end of the jib 17 may touch the ground via a base S (for example, a base stock). Alternatively, a support part (not shown) that is provided integrally with the main body of the boom 13 may touch the ground. When the tip of the boom 13 or the base end of the jib 17 touches the ground, the entire attachment A touches the ground (the state in which descent is completed). At this time, the entire attachment A is extended in a substantially straight line.

[0097] (Tracking position) If the hook 23 is not detached from the hoisting rope 25 when the jib tip 17a moves forward, the hook 23 and the hook holder 60 move following the movement of the jib tip 17a (step S73). At this time, it is preferable to be able to prevent contact between the jib tip 17a and the hook holder 60. For example, it is preferable that the hook holder 60 is disposed in a "following position" when the jib tip 17a moves forward (see step S61).

[0098] The followable position is a position around the jib tip 17a when the jib tip 17a is in contact with the ground (a position that does not overlap with the jib tip 17a). The followable position is a position of the hook holder 60 relative to the jib tip 17a that is suitable for the hook holder 60 to move to follow the jib tip 17a. The followable position is a position of the hook 23 and the hook holder 60 where the hook 23 and the hook holder 60 do not come into contact with the jib tip 17a. For example, the followable position may be a position a predetermined distance away from the jib tip 17a. Specifically, the followable position may include a position outside the jib tip 17a in the lateral direction Y (outside the jib width direction Y). More specifically, the followable position may include a position outside the jib width direction Y of a portion of the jib tip 17a that is positioned at the same height as the hook holder 60 (for example, the jib tip roller 17c). As shown in FIGS. 6 and 7, the followable position may include a position further outward in the front-rear direction X than the jib tip end 17a.

[0099] For example, the tracking position is preferably a position near the jib tip 17a shown in Fig. 7. More specifically, if the distance between the jib tip 17a and the hook holder 60 is too large, the following problem may occur. In this case, the weight of the hoisting rope 25 may cause, for example, the hook holder 60 to move in a direction approaching the jib tip 17a, causing the hoisting rope 25 to sag and touch the ground. Therefore, the tracking position is preferably set to a position near the jib tip 17a so as to prevent the hoisting rope 25 from touching the ground.

[0100] (How to place it in a tracking position) The position of the hook holder 60 relative to the jib tip 17a is set to the followable position, for example, as follows. When the jib tip 17a touches the ground (at step S57), the lowering of the boom 13 may be stopped, and the position of the hook holder 60 relative to the jib tip 17a may be adjusted to the followable position. Alternatively, the hook holder 60 may be placed at the followable position before the jib tip 17a touches the ground (see FIG. 4) (before step S57). In this case, the hook holder 60 may be placed at the followable position when the position of the hook holder 60 relative to the jib tip 17a is set to the contact avoidance position (at step S41). In this case, by placing the position of the hook holder 60 relative to the jib tip 17a at the contact avoidance position before the jib tip 17a touches the ground, the position of the hook holder 60 relative to the jib tip 17a is set to the followable position after the jib tip 17a touches the ground. Therefore, after the jib tip 17a touches the ground, there is no need to adjust (readjust) the positions of the hook 23 and the hook holder 60. In this case, the hook 23 and the hook holder 60 can be made to quickly follow the movement of the jib tip 17a after the jib tip 17a touches the ground.

[0101] (Hook 23 removal work) In the crane apparatus 1, an operation (hook 23 detaching operation, hook detaching step) is performed to detach the hook 23 from the hoisting rope 25 (from the jib tip 17a). When the hook 23 detaching operation is performed, it is preferable that the hook holder 60 is in a state (braking state) that restricts movement relative to the ground G. The position of the hook holder 60 when the hook 23 detaching operation is performed can be selected in various ways. When the hook 23 detaching operation is performed, the position of the jib tip 17a and whether or not the jib tip 17a is in contact with the ground can be selected in various ways.

[0102] [Example C1] The hook 23 removal work is preferably performed with the jib tip 17a on the ground, as shown in Figures 7 and 8. More specifically, if the hook 23 removal work is performed with the jib tip 17a not on the ground (floating above the ground G) as shown in Figure 4, the worker must perform the time-consuming hook 23 removal work while paying attention to the stability of the crane 10. On the other hand, if the hook 23 removal work is performed with the jib tip 17a on the ground as shown in Figures 7 and 8, the worker can perform the hook 23 removal work while the crane 10 is stable. This prevents the worker from having to pay attention to the stability of the crane 10 while performing the work.

[0103] [Example C1-1] As shown in Figure 7, the hook 23 removal operation may be performed when the jib tip 17a is on the ground and has not moved forward (when the jib tip 17a is at jib tip position P17a-1 immediately after touching the ground).

[0104] [Example C1-2] As shown in Figure 8, the hook 23 detachment work may be performed when the jib tip 17a is positioned forward X1 from the jib tip position P17a-1 of the jib tip 17a immediately after touching the ground (when the jib tip is positioned at P17a-2 after forward movement). [Example C1-2a] The hook 23 detachment work may be performed when the jib tip 17a is on the ground and the entire attachment A has not yet completed lowering (when the jib tip 17a is at jib tip position P17a-2a during forward movement). [Example C1-2b] The hook 23 detachment work may be performed when the jib tip 17a is on the ground, the entire attachment A has completed lowering, and the jib tip 17a has moved to the most forward X1 (when it is at jib tip position P17a-2b after forward movement is completed).

[0105] [Example C2] The hook 23 may be removed when the jib tip 17a is not in contact with the ground. For example, the hook 23 may be removed when the jib tip 17a shown in Figure 4 is lowered and approaches the ground G but is not in contact with the ground.

[0106] (Hook holder 60 after removing hook 23) When the hook 23 removal operation is performed, the hook 23 shown in FIG. 7 is placed on the hook holder 60 with the hoisting rope 25 detached (with the edge connected to the jib tip 17a severed). For example, in this state, at least one of the hook holder 60 and the hook 23 may be moved, for example, moved away from the jib 17 (from the attachment A). For example, at least one of the hook holder 60 and the hook 23 may be moved manually by an operator or moved by a transport vehicle (e.g., a forklift) not shown. The hook holder 60 may be towed or pushed. When the hook holder 60 and the hook 23 are moved, the hook holder 60 and the hook 23 may be moved together or separately.

[0107] When the attachment A is lowered, it is not necessary to remove the hook 23. For example, the attachment A may be lowered with the hook 23 still attached to the jib tip 17a, and the attachment A may be raised with the hook 23 still attached to the jib tip 17a, and the crane 10 may be placed in the working position (see FIG. 1).

[0108] (Consider) In the above embodiment, as shown in FIG. 7 , the hook 23 was placed on the hook holder 60 (step S33), which prevented the hook 23 from being dragged on the ground G when the jib tip 17a moved. Meanwhile, to prevent the hook 23 from being dragged, consider a case in which the hoisting rope 25 is let out in response to the movement of the jib tip 17a while the hook 23 is in a grounded state. In this case, if the hoisting rope 25 is a single-stranded rope between the hook 23 and the point sheave 21, the hook 23 can be prevented from being dragged, but there is a problem in that the hoisting rope 25 may be grounded (the details of the problem of grounding are described above). Furthermore, if the hoisting rope 25 is a multiple-stranded rope between the hook 23 and the point sheave 21, there is a problem in that the hoisting rope 25 may be grounded, and furthermore, the hook 23 cannot be prevented from being dragged. In this case, even if the hoisting rope 25 is reeled out, only a portion of the hoisting rope 25 (more specifically, the portion of the hoisting rope 25 between the point sheave 21 and the hook 23 that is closest to the hoisting winch 27, the so-called "first portion") will loosen. In this case, when the jib tip 17a moves, the hook 23 will be pulled by the other portion of the hoisting rope 25 (the portion other than the "first portion").

[0109] In the above embodiment, the hoisting rope 25 is wound up by the hoisting winch 27 when the jib tip 17a is lowered as shown in FIG. 4 (step S53). On the other hand, if the hoisting rope 25 is not wound up when the jib tip 17a is lowered, the hoisting rope 25 may come into contact with the ground (for example, it may come into contact with the ground in a coiled or helical manner). Furthermore, if the jib tip 17a advances while the hoisting rope 25 is in contact with the ground, the hoisting rope 25 is dragged. This may result in damage to the hoisting rope 25 (as described above in detail). Furthermore, if the jib tip 17a advances and the hoisting rope 25 changes from a slack state to a straight state (stretches), the hook 23 may be dragged, resulting in damage to the hook 23.

[0110] Furthermore, in the above embodiment, the hook holder 60 moved following the jib tip 17a (steps S55, S73), so it was possible to perform the work of detaching the hook 23 near the jib tip 17a. On the other hand, if the position where the work of detaching the hook 23 from the hoisting rope 25 is performed is far from the jib tip 17a, the following problem may arise. In this case, after the hook 23 is detached from the hoisting rope 25, when the hoisting winch 27 winds up the hoisting rope 25, there is a problem that the hoisting rope 25 is dragged on the ground G.

[0111] Furthermore, in the above embodiment, the hook 23 was movable while placed on the hook holder 60 (step S33). On the other hand, if the hook 23 is not placed on the hook holder 60 and is moved by a transport vehicle (e.g., a forklift) not shown, a transport vehicle is required. Therefore, if there is no transport vehicle at the work site of the crane 10, the attachment A cannot be lowered, or problems may occur such as the hook 23 and hoisting rope 25 touching the ground or being dragged. Furthermore, even if there is a transport vehicle at the work site of the crane 10, the same problem may occur if there is no transport vehicle driver. Furthermore, if the crane 10 is manually operated, a transport vehicle driver is required in addition to the operator of the crane 10.

[0112] It should be noted that the crane apparatus 1 may solve only some of the above problems.

[0113] (Effects of the first invention) The effects of the crane apparatus 1 shown in FIG. 4 are as follows. The crane apparatus 1 includes a crane body 11, an attachment A, a jib tip position information acquisition unit 41 (attachment tip position information acquisition unit) (see FIG. 2), a hoisting rope 25, a hoisting winch 27, a hook 23, and a hoisting winch control unit 53 (see FIG. 2). The attachment A is attached to the crane body 11 so that it can be raised and lowered. The jib tip position information acquisition unit 41 (see FIG. 2) acquires jib tip position information (attachment tip position information) related to the position of the tip of the jib 17 (the position of the tip of the attachment A; in the example shown in FIG. 4, jib tip position P17a of the jib tip 17a). The hoisting rope 25 is attached to the jib tip 17a (tip of the attachment A). The hoisting winch 27 winds and unwinds the hoisting rope 25. The hook 23 may be mounted on a hook holder 60 that is movable on the ground G. The hook 23 can be suspended from the jib tip 17a via a hoisting rope 25. The hoisting winch control unit 53 controls the operation of the hoisting winch 27.

[0114] [Configuration 1] The hoisting winch control unit 53 (see Figure 2) performs hoisting control during jib lowering (hoisting control during attachment lowering). The hoisting control during jib lowering is a control that causes the hoisting winch 27 to reel in the hoisting rope 25 based on the jib tip position information acquired by the jib tip position information acquisition unit 41 when the jib tip 17a is lowered with the hook 23 placed on the hook holder 60.

[0115] In the above [Configuration 1], when the jib tip portion 17a descends with the hook 23 placed on the hook holder 60, the hoisting winch 27 reels in the hoisting rope 25 based on the jib tip position information acquired by the jib tip position information acquisition unit 41. This prevents the hoisting rope 25 from sagging and coming into contact with the ground G. This prevents the hoisting rope 25 from coming into contact with the ground G when the jib tip portion 17a descends with the hook 23 lowered from the jib tip portion 17a.

[0116] If the hoisting rope 25 is wound too far onto the hoisting winch 27, the hook 23 may be lifted, which may cause the boom 13 and jib 17 (the crane 10) to become unstable. On the other hand, in the above [Configuration 1], the hoisting winch control unit 53 causes the hoisting winch 27 to wind the hoisting rope 25 based on the jib tip position information acquired by the jib tip position information acquisition unit 41. Therefore, if the hoisting winch 27 is caused to wind the hoisting rope 25 so that the hoisting rope 25 does not lift the hook 23, the following effect can be obtained. In this case, with the hook 23 lowered from the jib tip 17a, the boom 13 and jib 17 (the crane 10) can be stabilized when the jib tip 17a is lowered.

[0117] (Effects of the second invention) [Configuration 2] In the hoisting control when the jib is lowered (see [Configuration 1] above), the hoisting winch control unit 53 (see Figure 2) causes the hoisting winch 27 to wind up the hoisting rope 25 so that the hook holder 60 moves following the jib tip 17a due to the tension of the hoisting rope 25.

[0118] With the above [Configuration 2], the hook holder 60 can be moved following the jib tip 17a by the tension of the hoisting rope 25. Therefore, the hook holder 60 does not need to be equipped with a power source (such as a motor) for self-propelling following the jib tip 17a. Therefore, compared to when the hook holder 60 needs to be equipped with a power source, the hook holder 60 can be configured simply, made smaller and lighter, and manufactured inexpensively.

[0119] Furthermore, in the above [Configuration 2], in order to move the hook holder 60 following the jib tip 17a using the tension of the hoisting rope 25, it is sufficient that the hook 23 placed on the hook holder 60 and the jib tip 17a are connected by the hoisting rope 25. Therefore, there is a high degree of freedom in the arrangement of the jib tip 17a and the hook holder 60. For example, compared to when the bogie supporting the jib tip 17a is connected to the hook holder 60 (see, for example, Patent Document 1), the degree of freedom in the arrangement of the jib tip 17a and the hook holder 60 can be increased.

[0120] (Effect of the third invention) [Configuration 3] The crane apparatus 1 includes an attachment operating unit 33 (see FIG. 2) that performs an operation to lower the jib tip 17a. A hoisting winch control unit 53 (see FIG. 2) performs hoisting control when the jib is lowered (see [Configuration 1] above) in response to the operation of the attachment operating unit 33.

[0121] The above [Configuration 3] allows the operation for lowering the jib tip 17a (e.g., lowering the boom 13) to be linked with the control of the hoisting winch 27. Therefore, even if the coordinates of the position of the jib tip 17a are not acquired (calculated or detected), the hoisting winch 27 can be controlled in accordance with the operation of the attachment operating unit 33. Furthermore, when the operation for lowering the jib tip 17a is a manual operation, the operator of the crane 10 can also operate the hoisting winch 27 by performing the operation for lowering the jib tip 17a. Therefore, the operator can easily perform operations related to the lowering of the jib 17.

[0122] (Effect of the fourth invention) [Configuration 4] Hook holder 60 includes hook holder main body 61 and hook movement limiting portion 65. Hook 23 is placed on hook holder main body 61. Hook movement limiting portion 65 limits the movement of hook 23 relative to hook holder main body 61.

[0123] The above [Configuration 4] provides the following effect. In the above [Configuration 1], when the jib tip 17a descends, the hoisting winch 27 reels in the hoisting rope 25. At this time, the hook 23 is pulled by the hoisting rope 25, which may cause it to slip or fall off the hook holder main body 61. Therefore, in the above [Configuration 4], the hook 23 is fixed to the hook main body 23a by the hook movement restricting part 65. This makes it possible to prevent the hook 23 from slipping or falling off the hook holder main body 61.

[0124] (Effect of the fifth invention) The effects of the attachment A lowering method are as follows. The attachment A lowering method is used in a crane 10. The crane 10 includes a crane body 11, an attachment A, a hoisting rope 25, a hoisting winch 27, and a hook 23. The attachment A is attached to the crane body 11 so that it can be raised and lowered. The hoisting rope 25 is attached to the jib tip 17a. The hoisting winch 27 winds and unwinds the hoisting rope 25. The hook 23 may be mounted on a hook holder 60 that is movable on the ground G. The hook 23 can be suspended from the jib tip 17a via the hoisting rope 25. The attachment A lowering method includes a jib tip lowering step (attachment tip lowering step), a jib tip position information acquisition step (attachment tip position information acquisition step), and a jib lowering winding step (attachment lowering winding step).

[0125] [Configuration 5] In the jib tip lowering step, the jib tip 17a is lowered with the hook 23 placed on the hook holder 60. In the jib tip position information acquisition step, jib tip position information (attachment tip position information) regarding the position of the jib tip 17a is acquired when the jib tip lowering step is performed. In the jib lowering winding step, when the jib tip lowering step is performed, the hoisting winch 27 winds up the hoisting rope 25 based on the jib tip position information acquired in the jib tip position information acquisition step.

[0126] The above [Configuration 5] provides the same effect as the above "(Effect of the first invention)."

[0127] (Effect of the sixth aspect of the invention) [Configuration 6] In the hoisting step when the jib is lowered, the hoisting winch 27 winds up the hoisting rope 25 so that the hook holder 60 moves following the jib tip 17a due to the tension of the hoisting rope 25.

[0128] The above [Configuration 6] provides the same effect as the above "(Effect of the second invention)."

[0129] (Effect of the seventh invention) [Configuration 7] When the jib tip lowering step and the jib lowering hoisting step are performed, the hook holder 60 moves to a position Yo outside the jib width direction (outside the attachment width direction, outside the lateral direction Y) of the jib tip 17a, as shown in Figure 5.

[0130] Jib | Boom 4, when the jib 17 (attachment A) is lowered and the jib tip 17a approaches the ground G, interference between the jib tip 17a and the hook holder 60 can be suppressed. Therefore, damage to at least one of the jib tip 17a, the hook holder 60, and the hook 23 placed on the hook holder 60 can be suppressed.

[0131] (Effect of the eighth invention) The attachment A includes a boom 13 and a jib 17. The boom 13 is attached to the crane body 11 so as to be able to rise and fall. The jib 17 is attached to the boom 13 so as to be able to rise and fall. The hook 23 can be suspended from the tip of the jib 17 via a hoisting rope 25.

[0132] [Configuration 8] As shown in Figure 8, the attachment A lowering method includes a jib grounding boom lowering step and a jib grounding hook holder moving step. In the jib grounding boom lowering step, the jib tip 17a is lowered in the jib tip lowering step, so that the jib tip 17a touches the ground, and then the boom 13 is lowered. In the jib grounding hook holder moving step, the hook holder 60 moves following the jib tip 17a when the jib grounding boom lowering step is performed.

[0133] After the jib tip 17a touches the ground (see FIG. 7) by the jib grounding boom lowering step of [Configuration 8] above, the jib tip 17a moves forward while it is still on the ground. At this time, the hook holder 60 can be moved following the jib tip 17a by the jib grounding hook holder moving step. Therefore, the hook 23 placed on the hook holder 60 can be moved following the jib tip 17a. This increases the degree of freedom in selecting the position where work related to the hook 23 (for example, work to remove the hook 23 from the hoisting rope 25) is performed.

[0134] (Effect of the ninth invention) [Configuration 9] The attachment A lowering method includes a hook detaching step in which the hook 23 is detached from the hoisting rope 25 with the jib tip 17a in the ground.

[0135] In the above [Configuration 9], the hook 23 is detached from the hoisting rope 25 in a stable state where the jib tip 17a is on the ground (the crane 10 including the attachment A is in a stable state). Therefore, for example, it is possible to prevent a worker who is performing the work of detaching the hook 23 from the hoisting rope 25 from having to worry about the stability of the crane 10 while performing the work.

[0136] (Variation) The above-described embodiments may be modified in various ways. For example, the number of components (including modified examples) of the above-described embodiments may be changed, or some of the components may not be provided. For example, modified examples of the above-described embodiments may be combined in various ways. For example, components may be fixed or connected to each other directly or indirectly. For example, the connections of the components shown in FIG. 2 may be changed. For example, the arrangement of the components may be changed in various ways. For example, the inclusion relationships of the components may be changed in various ways. A component described as a lower-level component included in a higher-level component may not be included in this higher-level component, but may be included in another component. For example, what is described as multiple different members or parts may be combined into a single member or part. For example, what is described as a single member or part may be provided as multiple different members or parts. For example, various parameters (e.g., position, tension range, etc.) may be preset in the controller 50 or the like, or may be directly set by manual operation by an operator. For example, the various parameters may be fixed, may be changed manually, or may be automatically changed by the controller 50 or the like in response to certain conditions. For example, each component may have only a part of each characteristic (function, arrangement, shape, operation, etc.). [Explanation of symbols]

[0137] 1 Crane equipment 11 Crane body 13. Boom 17 Jib 17a Jib tip (tip of the jib, tip of the attachment) 23 Hook 25 Winding rope 27 Hoisting winch 33 Attachment operation section 41 Jib tip position information acquisition unit (attachment tip position information acquisition unit) 53 Hoisting winch control section 60 Hook holder 61 Hook holder body 65 Hook movement limiter A Attachment P17a Jib tip position (attachment tip position) Yo Outer side of jib width direction (outer side of attachment width direction)

Claims

1. The crane body, an attachment attached to the crane body in a manner that allows it to be raised and lowered; an attachment tip position information acquisition unit that acquires attachment tip position information relating to the position of the tip of the attachment; a hoisting rope attached to the tip of the attachment; a hoisting winch that winds and unwinds the hoisting rope; a hook that may be placed on a hook holder that is movable on the ground and that can be suspended from the tip of the attachment via the hoisting rope; a hoisting winch control unit that controls the operation of the hoisting winch; Equipped with the hoisting winch control unit performs hoisting control during attachment descent, which causes the hoisting winch to wind up the hoisting rope, based on the attachment tip position information acquired by the attachment tip position information acquisition unit, when the tip of the attachment is lowered with the hook placed on the hook holder. Crane equipment.

2. The crane apparatus according to claim 1, the hoisting winch control section, in the hoisting control during attachment descent, causes the hoisting winch to wind up the hoisting rope so that the hook holder moves following the tip end of the attachment due to tension of the hoisting rope. Crane equipment.

3. The crane apparatus according to claim 1 or 2, an attachment operating unit that performs an operation to lower the tip end of the attachment; The hoisting winch control unit performs hoisting control when the attachment is lowered in response to operation of the attachment operation unit. Crane equipment.

4. The crane apparatus according to claim 1 or 2, The hook holder is a hook holder main body on which the hook is placed; a hook movement limiting portion that limits movement of the hook relative to the hook holder main body portion; Equipped with Crane equipment.

5. The crane body, an attachment attached to the crane body in a manner that allows it to be raised and lowered; a hoisting rope attached to the tip of the attachment; a hoisting winch that winds and unwinds the hoisting rope; a hook that may be placed on a hook holder that is movable on the ground and that can be suspended from the tip of the attachment via the hoisting rope; A method for lowering an attachment of a crane comprising: an attachment tip lowering step in which the tip of the attachment is lowered with the hook placed on the hook holder; an attachment tip position information acquisition step of acquiring attachment tip position information relating to the position of the tip of the attachment when the attachment tip lowering step is performed; an attachment lowering hoisting step in which, when the attachment tip lowering step is performed, the hoisting winch winds up the hoisting rope based on the attachment tip position information acquired in the attachment tip position information acquisition step; Equipped with Attachment lowering method.

6. 6. The attachment lowering method according to claim 5, In the hoisting step during attachment descent, the hoisting winch winds up the hoisting rope so that the hook holder moves following the tip of the attachment due to tension of the hoisting rope. Attachment lowering method.

7. 7. The attachment lowering method according to claim 5 or 6, When the attachment tip lowering step and the attachment lowering hoisting step are performed, the hook holder moves to a position that is more outward in the attachment width direction than the tip of the attachment. Attachment lowering method.

8. 7. The attachment lowering method according to claim 5 or 6, The attachment is a boom attached to the crane body so as to be able to be raised and lowered; a jib attached to the boom so as to be able to be raised and lowered; Equipped with The hook can be suspended from the tip of the jib via the hoisting rope, a jib grounding boom lowering step in which the boom is lowered after the tip of the jib is lowered by the attachment tip lowering step and the tip of the jib is grounded; a jib grounding hook holder moving step in which the hook holder moves following the tip of the jib when the jib grounding boom lowering step is performed; Equipped with Attachment lowering method.

9. 7. The attachment lowering method according to claim 5 or 6, a hook detaching step in which the hook is detached from the hoisting rope with the tip of the attachment in contact with the ground; Attachment lowering method.

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