Crane and crane control method

Abstract

To provide a crane capable of landing a suspended load at an accurate position, and a method for controlling the crane.SOLUTION: When a lifter 12 clamps a slab SL, a control unit 10 moves a trolley 11 horizontally so as to reduce the amount of horizontal deviation between the slab SL and the trolley 11. This allows the lifter 12 to lift the slab SL without tilting the slab SL. The lifter 12 lands the slab SL in this state, so that the slab SL can be landed in the correct position and orientation.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a crane and a method for controlling a crane. [Background technology]

[0002] Conventionally, there is known a crane that lifts a load by clamping the sides of the load with a hoisting part (see, for example, Patent Document 1). This crane has a pair of claws, and holds the load by clamping both sides of the load with the pair of claws. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 6-127887 Summary of the Invention [Problem to be solved by the invention]

[0004] Here, the load hoisted by the crane may bend or bend when a hot load is hoisted (see slab SL in Figure 2). If there is a misalignment between the crane and the load when it is clamped by the crane, the load may tilt when lifted, and the bent load may rotate when it lands on the floor (see Figure 9(b)).

[0005] The present invention has been made to solve such problems, and has an object to provide a crane that can land a suspended load in an accurate position, and a method for controlling the crane. [Means for solving the problem]

[0006] The crane of the present invention is a crane that hoists a load by clamping the side of the load, and comprises a crane main body that can move horizontally, a lifter that is capable of rising and lowering relative to the crane main body and has at least a pair of claw portions that clamp the side of the load from both sides, a mast that is tiltably connected to the lifter and can rise and fall along with the lifter, a mast guide that guides the raising and lowering of the mast, and a control unit that controls the movement of the crane, and when the lifter clamps the load, the control unit moves the crane main body horizontally so as to reduce the amount of horizontal deviation between the load and the crane main body.

[0007] In the crane, a lifter having at least a pair of claws that clamp the side of a load from both sides is provided so as to be able to rise and fall relative to the crane body. The crane also includes a mast that is tiltably connected to the lifter and can rise and fall with the lifter, and a mast guide that guides the rise and fall of the mast. Therefore, if the lifter completes the clamping operation of the load in a state where it is misaligned with the crane body and lifts the load, the load may tilt. In response to this, when the lifter clamps the load, the control unit moves the crane body horizontally so as to reduce the amount of horizontal deviation between the load and the crane body. This allows the lifter to lift the load without tilting it. The lifter lands the load in this state, so that the load can be landed in an accurate position. As described above, the rotation of the load when it lands can be suppressed.

[0008] The lifter may include a lifter body and a pin that tiltably connects the lifter body and the mast, thereby enabling the lifter and the mast to be tiltably connected with a simple configuration.

[0009] The crane may further include a tilt detection unit that detects the tilt of the lifter with respect to the normal state. This allows the crane to directly detect the tilt of the lifter with respect to the normal state, which may cause the load to tilt.

[0010] The control unit may detect the direction of positional deviation of the load relative to the crane body based on detecting the inclination of the lifter caused when one of a pair of claws engages the load first when the lifter grabs the load, and may correct the positional deviation between the crane body and the load by horizontally moving the crane body in the direction of the positional deviation. In this way, by correcting the positional deviation between the crane body and the load, it is possible to eliminate the inclination of the load when the lifter lifts it.

[0011] The crane may further include a gap detector that detects the gap between the mast of the main body and the mast guide at two or more positions in the vertical direction in order to detect the inclination of the mast. In this case, the inclination of the mast that causes the load to tilt can be detected via the gap between the mast and the mast guide.

[0012] The control unit may detect the direction of misalignment of the load relative to the crane body based on detecting the tilt of the mast caused by one of the pair of claws engaging the load first when the lifter grabs the load, and correct the misalignment between the crane body and the load by horizontally moving the crane body in the direction of the misalignment. In this way, by correcting the misalignment between the crane body and the load, it is possible to eliminate the tilt of the load when the lifter lifts it.

[0013] The allowable mechanical misalignment caused by the gap between the mast of the main body and the mast guide may be equal to or greater than the stopping distance for the crane main body to stop after the correction of the misalignment between the crane main body and the suspended load is completed. In this case, it is possible to prevent an excessive load from being applied to the mast due to inertia after the correction of the misalignment between the main body and the suspended load is completed.

[0014] The crane control method of the present invention is a method for controlling a crane that lifts a load by clamping the sides of the load, the crane comprising a crane main body that can move horizontally, a lifter that is capable of raising and lowering relative to the crane main body, a mast that is tiltably connected to the lifter and can be raised and lowered along with the lifter, and a mast guide that guides the raising and lowering of the mast, and when the load is clamped by the lifter, the crane main body is moved horizontally so as to reduce the amount of horizontal deviation between the load and the crane main body.

[0015] According to the control method for the crane, it is possible to obtain the same functions and effects as those of the crane described above. Effect of the Invention

[0016] According to the present invention, there are provided a crane and a method for controlling a crane that can land a suspended load at an accurate position. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is a diagram showing a crane 1 according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a view of the lifter seen from the traveling direction. [Diagram 3] FIG. 3(a) is a view of the lifter seen from the lateral direction, and FIG. 3(b) is a view of the lifter seen from above. [Figure 4] FIG. [Diagram 5] FIG. [Figure 6] FIG. [Figure 7] FIG. 11 is a diagram showing the operation of a crane according to a comparative example. [Figure 8] FIG. 11 is a diagram showing the operation of a crane according to a comparative example. [Figure 9] FIG. 11 is a diagram showing the operation of a crane according to a comparative example. [Figure 10] FIG. 2 is a diagram showing a mast and a mast guide. [Figure 11]10 is a flowchart showing the processing contents by a control unit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a crane 1 according to an embodiment of the present invention. Here, an overhead crane is shown as an example of the crane 1. As shown in FIG. 1, the crane 1 is a device that holds a slab SL (suspended load) with a hoist (lifter) 12 and moves the lifter 12 together with the slab SL. Note that the crane 1 is not limited to an overhead crane, and may be a hoist crane, a gantry crane, a bridge crane, a jib crane, or the like. In addition, the suspended load is not limited to a slab, and may be any article whose sides can be clamped by the claws, and a wooden board or the like may be used.

[0019] As shown in Fig. 1, the crane 1 comprises a crane body 6 and a lifter 12. The crane body 6 comprises a girder 3, a trolley 11, a traveling device 7, a traverse device 8, and a control unit 10. The trolley 11 is movable horizontally and can move in the traverse direction D2 and the traveling direction D1. The lifter 12 is suspended from the trolley 11 by a wire 39, and is supported so as to be able to rise and fall relative to the trolley 11 by winding up and down the wire 39. The lifter 12 is a device having at least a pair of claws 31 that clamp the slab SL from both sides.

[0020] The rail 2 is a member that guides the movement of the trolley 11 in the traveling direction D1 via the girder 3. The rail 2 is a pair of guide members that are spaced apart from each other in the lateral direction D2 and extend parallel to the traveling direction D1. The rail 2 is fixed near the ceiling of the building in which the crane 1 is installed. The girder 3 is a pair of members that guide the movement of the lifter 12 in the lateral direction D2 via the trolley 11. The girder 3 is a pair of guide members that are spaced apart from each other in the traveling direction D1 and extend parallel to the lateral direction D2 so as to be spanned across the pair of rails 2. The trolley 11 suspends the lifter 12 while being supported by the girder 3. The trolley 11 can travel in the lateral direction D2 along the girder 3 by a lateral travel device 8 described later.

[0021] The traveling devices 7 are devices for causing the girder 3 to travel in the traveling direction D1 along the rail 2. The traveling devices 7 are provided at both ends of the girder 3 in the lateral direction D2. Each traveling device 7 has wheels 21. The lateral travel device 8 is a device for causing the trolley 11 to travel lateral along the girder 3. The lateral travel device 8 has wheels 22 provided on the trolley 11.

[0022] The lifter 12 is suspended from the trolley 11 by a wire 39. The lifter 12 is moved up and down by winding up or down the wire 39 by a drum (not shown) provided on the trolley 11.

[0023] The crane 1 is equipped with a sway suppression mechanism 70 for suppressing the sway of the lifter 12. The sway suppression mechanism 70 has a mast guide 45 extending vertically downward from the lower surface of the trolley 11, and a mast 13 that can be raised and lowered along the mast guide 45. The mast guide 45 guides the raising and lowering of the mast 13. The mast 13 is connected to the lifter 12 so as to be tiltable, and can be raised and lowered together with the lifter 12. The mast 13 moves relatively in the vertical direction with respect to the mast guide 45 as the lifter 12 rises and falls. The lifter 12 is connected to the lower end of the mast 13 so as to be tiltable by a pin or the like.

[0024] The control unit 10 is a device that comprehensively controls the entire crane 1. The control unit 10 controls the crane 1 to lift, move, and land the slab SL. The control unit 10 is composed of, for example, a programmable logic controller. The control unit 10 may also be composed of a general computer.

[0025] Next, the lifter 12 will be described with reference to Figures 2 and 3, and the detailed configuration of the vibration suppression mechanism 70 will be described with reference to Figure 10(a). Figure 2 is a view of the lifter 12 as seen from the running direction D1. Figure 3(a) is a view of the lifter 12 as seen from the lateral direction D2. Figure 3(b) is a view of the lifter 12 as seen from above. The lifter 12 suspends a slab SL that is arranged so that its longitudinal direction is in the lateral direction D2. The slab SL has side surfaces SLa and SLb on both sides of the running direction D1, which is the short side direction.

[0026] As shown in FIG. 2 and FIG. 3, the lifter 12 includes a lifter body 30, a claw 31, and a pin 37. The lifter body 30 includes an extension 33, a pair of support parts 34, 35, and a pillar 36. The extension 33 is a member extending in the lateral direction D2. The pair of support parts 34, 35 are provided at both ends of the extension 33 in the lateral direction D2. The pair of support parts 34, 35 extend from the extension 33 to both sides in the running direction D1. The pillar 36 is a member extending upward from the center position of the extension 33 in the lateral direction D2. The pin 37 connects the lifter body 30 and the mast 13 to be tiltable. Specifically, the upper end of the pillar 36 and the lower end of the mast 13 are connected to be rotatable via the pin 37. The pin 37 rotatably connects the lifter body 30 of the lifter 12 to the mast 13, with an axis extending in the lateral direction D2 as the rotation axis (see, for example, FIG. 5(a)). In this manner, the lifter 12 is provided rotatably with respect to the mast 13 and the trolley 11. The pin 37 may be fixed to the mast 13.

[0027] A pair of claws 31A, 31B are provided on the support parts 34, 35, respectively. The claws 31A, 31B are provided on the lower surfaces of the support parts 34, 35. The claw 31A is provided on one side of the extension part 33 in the running direction D1. The claw 31B is provided on the other side of the extension part 33 in the running direction D1. The lower ends of the claws 31A, 31B are provided with a holding part 31a that protrudes toward the center in the running direction D1 (see FIG. 3(a)). The claws 31A, 31B can be electrically driven to move horizontally along the support parts 34, 35 to the outside and inside in the running direction D1. This allows the claws 31A, 31B to hold the slab SL while sandwiching the slab SL. The holding part 31a of the claw 31A comes into contact with the side surface SLa of the slab SL. The holding portion 31a of the claw portion 31B comes into contact with the side surface SLb of the slab SL.

[0028] 2, a lifter lifting sheave 38 is provided above the support parts 34, 35. The lifter lifting sheave 38 is a member around which a wire 39 is wound, and which moves the lifter 12 up and down by winding up and down a drum (not shown) provided on the trolley 11.

[0029] 3(a), when the lifter 12 is gripping the slab SL normally, the lifter 12 and the slab SL are disposed directly below the mast 13. At this time, the central axis CL1 of the mast 13, the central axis CL2 of the lifter 12, and the central axis CL3 of the slab SL are aligned with each other.

[0030] The crane 1 is equipped with an inclination detection unit 40 that detects the inclination of the lifter 12 in order to detect the movement of the lifter 12. The inclination detection unit 40 is provided on the lifter body 30 so that it is horizontal in the normal state. The inclination detection unit 40 can detect the inclination of the lifter 12 with respect to the normal state by detecting the inclination of the lifter body 30 with respect to the horizontal.

[0031] As shown in FIG. 10(a), in the sway suppression mechanism 70, the mast 13 is surrounded by the mast guide 45. Annular bushes 46 are provided on the inner periphery of the mast guide 45 near the upper end and the lower end. The bushes 46 are members that restrict the inclination of the mast 13. In this way, when the mast 13 sways, the mast guide 45 can suppress the increase in the sway of the mast 13 by the bushes 46. The crane 1 may grasp the inclination state of the mast 13 instead of the inclination detection unit 40 that detects the inclination of the lifter 12, or together with the inclination detection unit 40. In order to detect the inclination of the mast 13, the crane 1 may include a gap detection unit 48 that detects the gap between the mast 13 and the mast guide 45 at two or more points in the vertical direction. The gap detection unit 48 can detect the size of the gap by measuring the distance between the gap detection unit 48 and the outer circumferential surface of the mast 13 at that height position. When the lifter 12 tilts relative to the trolley 11, the mast 13 also tilts accordingly within the range of the mast guide 14. The tilt state of the mast 13 can be grasped based on the size of the gap between the upper and lower ends of the mast guide 45. In Fig. 10(b), the state when the mast 13 is tilted to the left and right to the maximum is set according to the positional relationship with the pair of upper and lower bushes 46 (the state shown by the phantom lines). The state shown by the phantom lines in Fig. 10(b) is the maximum tilt of the mast 13, and swing is suppressed.

[0032] As shown in FIG. 10(b), the allowable width W of mechanical positional deviation caused by the gap between the mast 13 of the trolley 11 and the mast guide 45 may be equal to or greater than the stopping distance for the trolley 11 to stop after the correction of the positional deviation between the trolley 11 and the slab SL (details will be described later) is completed. The amount of movement of the lower end between the state in which it is tilted to the left to the maximum extent and the state in which it is tilted to the right to the maximum extent is the allowable width W of positional deviation. On the other hand, when the trolley 11 moves sideways or travels due to the positional deviation and the correction is completed, a stop signal is given to the trolley 11. However, even if a stop signal is given, the trolley 11 moves slightly due to inertia. In contrast, the allowable width W of positional deviation is equal to or greater than the stopping distance for the trolley 11 to stop. Therefore, the movement of the mast 13 due to the inertia of the trolley 11 is permitted within the range of the allowable width W of positional deviation.

[0033] Next, the operation of the crane 1 according to this embodiment will be described. When the lifter 12 clamps the slab SL, the crane 1 performs a correction operation to eliminate the tilt that occurs when the slab SL is lifted. This control, which corrects the positional deviation between the trolley 11 and the slab SL by moving the trolley 11 laterally or traveling in the positional deviation direction, is automatically performed by the control unit 10 (see FIG. 1).

[0034] The operation of the crane 1 will be described with reference to Figs. 4 to 6 and Fig. 11. Fig. 11 is a flow chart showing the control contents by the control unit 10. Fig. 11 shows the processing contents when the lifter 12 reaches a position immediately before gripping the slab SL. As shown in Fig. 4, the control unit 10 controls the crane 1 so that the lifter 12 grips the slab SL on the placement unit 50 (Fig. 11: step S100). In the state shown in Fig. 4, the central axis CL3 of the slab SL is misaligned with the central axis CL1 of the mast 13. When the lifter 12 closes the claws 31A and 31B in this state, only one of the claws 31A contacts the side surface SLa of the slab SL. When the claws 31A and 31B are closed in this state, the lifter 12 rotates around the pin 37 and tilts with respect to the mast 13 as shown in Fig. 5(a).

[0035] At this time, the inclination detection unit 40 detects that the lifter 12 has inclined relative to the trolley 11 (see FIG. 1) and the mast 13. The control unit 10 detects the misalignment direction of the slab SL relative to the trolley 11 based on the detection of the inclination of the lifter 12 caused by one of the pair of claws 31A, 31B (claw 31A) engaging with the slab SL first (FIG. 11: step S110). Here, the control unit 10 detects that the claw 31A side of the traveling direction D1 is the misalignment direction. In addition, the gap detection unit 48 detects the inclination of the mast 13. The control unit 10 detects the misalignment direction of the slab SL relative to the trolley 11 based on the detection of the inclination of the mast 13 caused by one of the pair of claws 31A, 31B (claw 31A) engaging with the slab SL first (FIG. 11: step S120). Note that FIG. 11 shows an example in which both steps 110 and 120 are executed, but the present invention is not limited thereto. Either step 110 or step 120 may be executed to detect the direction of positional deviation of the slab SL relative to the trolley 11.

[0036] As shown in FIG. 5(b), when the control unit 10 detects the positional deviation direction of the slab SL relative to the trolley 11 due to at least one of the inclination of the lifter 12 and the inclination of the mast 13 during the operation of clamping the slab SL, the control unit 10 corrects the positional deviation between the trolley 11 and the slab SL by horizontally moving the trolley 11 in the traveling direction D1, which is the positional deviation direction (FIG. 11: step S130). In this way, the control unit 10 moves the trolley 11 horizontally so as to reduce the amount of deviation between the slab SL and the trolley 11 in the horizontal direction. When the control unit 10 detects that the inclination of the lifter 12 has been eliminated, the control unit 10 resumes the operation of closing the claws 31A and 31B (FIG. 11: step S140). The control unit 10 determines whether the lifter 12 has completed the gripping operation of the slab SL (FIG. 11: step S150). If not completed, the process is repeated from step S100. When the control unit 10 detects at least one of the inclination of the lifter 12 and the inclination of the mast 13 again during the operation of clamping the slab SL, it performs the correction operation again. In this way, the control unit 10 continues this correction control during the closing operation of the claw portions 31A, 31B. The control unit 10 moves to the next process when the lifter 12 has finished gripping the slab SL with both claw portions 31A, 31B (FIG. 11: YES in step S150). As a result, the inclination of the lifter 12 is eliminated, and the central axis CL2 of the lifter 12 coincides with the central axis CL1 of the mast 13. Furthermore, the positional deviation of the mast 13 relative to the slab SL is corrected, so that the deviation between the central axis CL1 of the mast 13 and the central axis CL2 of the slab SL is reduced.

[0037] The control unit 10 transfers the slab SL held by the lifter 12 from the placement unit 50 to a new placement unit 51 (FIG. 11: step S160). When the positional deviation of the slab SL relative to the trolley 11 is reduced, the lifter 12 is wound up together with the slab SL, as shown in FIG. 6(a). As a result, the slab SL moves upward away from the placement unit 50 while maintaining the horizontal position. In this state, the slab SL is suspended without tilting, with the central axis CL3 kept vertical. As shown in FIG. 6(b), when the lifter 12 arrives at the position of the new placement unit 51, which is the destination position, the lifter 12 is lowered to place the slab SL on the placement unit 51. At this time, the slab SL is placed on the new placement unit 51 without tilting, with the central axis CL3 kept vertical.

[0038] Next, the functions and effects of the crane 1 and the control method for the crane 1 according to this embodiment will be described.

[0039] First, the operation of the crane 100 according to the comparative example will be described with reference to Figures 7 to 9. As shown in Figure 7(a), when the position of the central axis CL3 of the slab SL is deviated from the central axis CL1 of the mast 13, only one of the claws 31A comes into contact with the slab SL first. When the claws 31A and 31B are further closed in this state, the lifter 12 clamps the slab SL in a state in which it is tilted with respect to the mast 13 (i.e., the trolley 11) as shown in Figure 7(b).

[0040] When the lifter 12 suspends the slab SL in this state, as shown in FIG. 8(a), the inclination of the lifter 12 returns to normal, and the center of gravity of the lifter 12 and the slab SL is located directly below the mast 13. At this time, the slab SL is suspended from the lifter 12 in a state inclined with respect to the trolley 11. Therefore, the central axis CL3 of the slab SL is in a state inclined with respect to the vertical direction. In this case, as shown in FIG. 8(b), when the lifter 12 lands the slab SL on the new placement part 51, only one end side of the slab SL in the running direction D1 comes into contact with the placement part 51 first. At this time, a torque is generated that tries to return the slab SL to the horizontal position, and the mast 13 supports this torque. Therefore, a force F1 is input to the mast 13.

[0041] Here, the slab SL may be warped and not be a uniform plane. For example, the slab SL may be warped so as to be convex downward (see FIG. 2). In this case, a part of the slab SL in the longitudinal direction first comes into contact with the placement part 51. Therefore, as shown in FIG. 9(a), the installation point TP of the slab SL is set at one end side in the traveling direction D1, and at a part of the longitudinal direction (lateral direction D2). Also, if the installation point TP and the mast 13 are misaligned in the lateral direction D2, the force F1 input to the mast 13 and the force F2 acting on the installation point TP push against each other, generating a torque that rotates the slab SL and the lifter 12 in a horizontal plane. Therefore, as shown in FIG. 9(b), the slab SL and the lifter 12 rotate, and the direction and position of the slab SL on the placement part 51 are misaligned.

[0042] In the crane 1 according to this embodiment, the lifter 12, which has at least a pair of claws 31A, 31B that clamp the side surface of the slab SL from both sides, is provided so as to be able to ascend and descend with respect to the trolley 11. The crane 1 also includes a mast 13 that is tiltably connected to the lifter 12 and can ascend and descend with the lifter 12, and a mast guide 45 that guides the ascending and descending of the mast 13. Therefore, when the lifter 12 clamps the slab SL, if the lifter 12 clamps the slab SL while being misaligned with the trolley 11 and lifts the slab SL, the slab SL may be tilted (see FIG. 8(a)). In response to this, the control unit 10 moves the trolley 11 horizontally so as to reduce the amount of misalignment between the slab SL and the trolley 11 in the horizontal direction when the lifter 12 clamps the slab SL. This allows the lifter 12 to lift the slab SL without tilting it. Since the lifter 12 lands the slab SL in this state, the slab SL can be landed in the correct position and orientation. As a result, the slab SL can be landed in the correct position.

[0043] The lifter 12 may include a lifter body 30 and a pin 37 that tiltably connects the lifter body 30 to the mast 13. This makes it possible to tiltably connect the lifter 12 to the mast 13 with a simple configuration.

[0044] The crane 1 may include a tilt detection unit 40 that detects the tilt of the lifter 12 in order to detect the movement of the lifter 12. This allows the crane 1 to directly detect the tilt of the lifter 12, which may cause the slab SL to tilt.

[0045] The control unit 10 may detect the direction of positional deviation of the slab SL relative to the trolley 11 based on the detection of the inclination of the lifter 12 caused when one of the pair of claws 31A, 31B engages with the slab SL first when the lifter 12 grips the slab SL, and correct the positional deviation between the trolley 11 and the slab SL by horizontally moving the trolley 11 in the positional deviation direction. In this way, by correcting the positional deviation between the trolley 11 and the slab SL, the inclination of the slab SL can be eliminated when the lifter 12 lifts the slab SL.

[0046] The crane 1 may include a gap detection unit 48 that detects the gap between the mast 13 and the mast guide 45 at two or more locations in the vertical direction in order to detect the inclination of the mast 13. In this case, the inclination of the mast 13 that causes the slab SL to incline can be detected via the gap between the mast 13 and the mast guide 45.

[0047] The control unit 10 may detect the direction of positional deviation of the slab SL relative to the trolley 11 based on the inclination of the mast 13 caused when one of the pair of claws 31A, 31B engages with the slab SL first when the lifter 12 grips the slab SL, and correct the positional deviation between the trolley 11 and the slab SL by horizontally moving the trolley 11 in the direction of positional deviation. In this way, by correcting the positional deviation between the crane main body and the suspended load, it is possible to eliminate the inclination of the suspended load when the lifter lifts the suspended load.

[0048] As shown in FIG. 10(b), the allowable width W of mechanical positional deviation due to the gap between the mast 13 and the mast guide 45 may be equal to or greater than the stopping distance for the trolley 11 to stop after the correction of the positional deviation between the trolley 11 (see FIG. 1) and the slab SL is completed. When the trolley 11 moves laterally or travels due to the positional deviation and the correction is completed, a stop signal is given to the trolley 11. However, even if a stop signal is given, the mast 13 moves slightly together with the trolley 11 due to inertia. In contrast, the movement of the mast 13 due to inertia is allowed within the range of the allowable width W of positional deviation. As a result, even if the trolley 11 and the mast 13 move due to inertia after the correction of the positional deviation between the trolley 11 and the slab SL is completed, it is possible to avoid the occurrence of excessive load on the mast 13 and the mast guide 45.

[0049] The control method of the crane 1 in this embodiment is a control method of the crane 1 that lifts a slab SL by clamping the side of the slab SL, and the crane 1 is equipped with a trolley 11 that can move horizontally, a lifter 12 that is arranged to be able to rise and lower relative to the trolley 11, a mast 13 that is tiltably connected to the lifter 12 and can be raised and lowered along with the lifter 12, and a mast guide 45 that guides the raising and lowering of the mast 13, and when the slab SL is clamped by the lifter 12, the trolley 11 is moved horizontally so as to reduce the amount of horizontal deviation between the slab SL and the trolley 11.

[0050] According to the control method for the crane 1, it is possible to obtain the same functions and effects as those of the crane 1 described above.

[0051] The present invention is not limited to the above-described embodiments.

[0052] In the above embodiment, the inclination of the lifter 12 with respect to the normal state is detected by the inclination detection unit 40. Alternatively or in addition to this, other detection methods may be adopted. [Explanation of symbols]

[0053] 1...crane, 6...crane main body, 11...main body (crane main body), 12...lifter, 13...mast, 30...lifter main body, 31, 31A, 31B...claw portion, 37...pin, 40...tilt detection portion, 45...mast guide, 48...gap detection portion, SL...slab (suspended load).

Claims

1. A crane that lifts a load by clamping the sides of the load, A crane body that is movable in a horizontal direction; A lifter that is provided so as to be able to rise and fall relative to the crane body and has at least a pair of claws that clamp the side surfaces of the suspended load from both sides; a mast connected to the lifter so as to be tiltable and capable of ascending and descending together with the lifter; A mast guide that guides the elevation and lowering of the mast; A control unit for controlling the movement of the crane, A crane in which the control unit moves the crane body horizontally so as to reduce the amount of horizontal deviation between the load and the crane body when the lifter clamps the load.

2. The crane according to claim 1 , wherein the lifter comprises a lifter body and a pin that tiltably connects the lifter body and the mast.

3. The crane according to claim 2 , further comprising an inclination detection unit that detects an inclination of the lifter relative to a normal state.

4. The control unit detects a positional deviation direction of the load relative to the crane body based on detecting an inclination of the lifter caused by one of the pair of claw portions first engaging with the load when the lifter grasps the load, The crane according to claim 3 , wherein the positional deviation between the crane body and the suspended load is corrected by horizontally moving the crane body in the positional deviation direction.

5. 3. The crane according to claim 1, further comprising a gap detection unit that detects a gap between the mast and the mast guide at two or more locations in the vertical direction in order to detect an inclination of the mast.

6. The control unit detects a positional deviation direction of the load relative to the crane body based on detecting an inclination of the mast caused by one of the pair of claw portions first engaging with the load when the lifter grasps the load, The crane according to claim 5 , wherein the positional deviation between the crane body and the suspended load is corrected by horizontally moving the crane body in the positional deviation direction.

7. 7. The crane according to claim 6, wherein a mechanical positional misalignment allowable width due to a gap between the mast and the mast guide is equal to or greater than a stopping distance for the crane body to stop after correction of the positional misalignment between the crane body and the suspended load is completed.

8. A method for controlling a crane that lifts a load by clamping the sides of the load, comprising the steps of: The crane includes: A crane body that is movable in a horizontal direction, and a lifter that is provided so as to be able to rise and fall relative to the crane body; a mast connected to the lifter so as to be tiltable and capable of ascending and descending together with the lifter; a mast guide for guiding the elevation and lowering of the mast; A method for controlling a crane, comprising: moving the crane body in a horizontal direction so as to reduce the amount of horizontal deviation between the load and the crane body when the lifter clamps the load.

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