Hoisting device and hoisting load attitude adjustment method

Abstract

To quickly set a suspended load in a horizontal state.SOLUTION: A suspension apparatus 100 comprises: four or more suspension ropes 10 extending from a crane suspension tool 1 toward a suspended load 2; a chain block 20 that is provided for each suspension rope 10 and that adjusts a distance between a first load point P1 at which a load of the suspended load 2 is applied on the suspension rope 10 and a second load point P2 at which the load of the suspended load 2 is applied on the suspension tool 1 via the suspension rope 10; an inclination angle measurement device 30 that measures the inclination angle of the suspended load 2 with respect to a horizontal surface; and a control device 40 that adjusts the attitude of the suspended load 2 by controlling the chain block 20 on the basis of the inclination angle measured by the inclination angle measurement device 30. The control device 40 selects one reference suspension rope serving as a reference from among the suspension ropes 10 on the basis of the heights of a plurality of first load points P1 in a vertical direction, and simultaneously activates all chain blocks 20 other than a chain block 20 provided to the reference suspension rope to adjust the attitude of the suspended load 2.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a lifting device and a method for adjusting the posture of a suspended load.

Background Art

[0002] Patent Document 1 discloses a lifting device including a plurality of suspension ropes for lifting a suspended load, and a suspension rope length changing device capable of changing the length of each suspension rope, and controlling the suspension rope length changing device so that the suspended load becomes horizontal in a state where the suspended load is lifted. In the lifting device described in Patent Document 1, the inclination in the X-axis direction and the Y-axis direction intersecting on a horizontal plane is detected respectively, and after controlling the suspension rope length changing device so that the inclination in the X-axis direction becomes horizontal, the suspension rope length changing device is controlled so that the inclination in the Y-axis direction becomes horizontal.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the lifting device described in Patent Document 1, the adjustment control for making the suspended load horizontal is performed separately for the adjustment in the X-axis direction and the adjustment in the Y-axis direction. When the adjustment control for making the suspended load horizontal is performed in two steps in this way, if load swing occurs in the adjustment control performed first, the subsequent adjustment control cannot be performed until the load swing sufficiently converges. For this reason, it takes time to make the suspended load horizontal, and as a result, the time required for the lifting operation may become long.

[0005] An object of the present invention is to quickly make a suspended load horizontal.

Means for Solving the Problems

[0006] The present invention relates to a suspension device, comprising: four or more suspension cables extending from a lifting tackle of a crane towards a suspended load; a distance adjustment device provided for each of the suspension cables to adjust a distance between a first load point at which the load of the suspended load acts on the suspension cable and a second load point at which the load of the suspended load acts on the lifting tackle via the suspension cable; an inclination angle measurement device for measuring an inclination angle of the suspended load with respect to a horizontal plane; and a control device for adjusting the posture of the suspended load by controlling the distance adjustment device based on the inclination angle measured by the inclination angle measurement device. The control device selects one reference suspension cable as a reference from among the suspension cables based on the height of a plurality of the first load points in the vertical direction, In the state where the suspended load is suspended, and adjusts the posture of the suspended load by simultaneously operating all the other distance adjustment devices except the distance adjustment device provided for the reference suspension cable.

Advantages of the Invention

[0007] According to the present invention, the suspended load can be quickly brought into a horizontal state.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Best Mode for Carrying Out the Invention

[0009] Hereinafter, with reference to the drawings, a suspension device and a suspended load attitude adjustment method according to an embodiment of the present invention will be described.

[0010] First, with reference to FIGS. 1 and 2, a suspension device 100 according to an embodiment of the present invention will be described. FIG. 1 is a simplified perspective view of the suspension device 100, and FIG. 2 is a system configuration diagram of the suspension device 100.

[0011] As shown in FIGS. 1 and 2, the suspension device 100 includes four suspension cables 10 extending from a suspension tool 1 such as a suspension hook of a crane (not shown) toward a suspended load 2, and is provided for each suspension cable 10, and between a first load point P1 where the load of the suspended load 2 acts on the suspension cable 10 and a second load point P2 where the load of the suspended load 2 acts on the suspension tool 1 via the suspension cable 10. A chain block (distance adjustment device) 20 for adjusting the distance, an inclination angle measurement device 30 for measuring the inclination angle of the suspended load 2 with respect to the horizontal plane, and a control device 40 for adjusting the attitude of the suspended load 2 by controlling the chain block 20 based on the inclination angle measured by the inclination angle measurement device 30.

[0012] In the embodiment shown in FIG. 1, the load of the suspended load 2 acts on each suspension cable 10 via a suspension balance 4. The suspension balance 4 is a rectangular frame structure composed of a pair of main members 5 arranged in parallel with each other and three connecting members 6 connecting the pair of main members 5 at both ends and the center in the longitudinal direction of the main members 5. For the main members 5 and the connecting members 6, shape steel with an H-shaped or I-shaped cross section can be used. Note that, without using the suspension balance 4, the suspended load 2 may be directly lifted by each suspension cable 10, and the load of the suspended load 2 may act directly on each suspension cable 10 without passing through the suspension balance 4.

[0013] On the upper surface of the main material 5 of the hanging scale 4, four hanging pieces 7 to which four suspension ropes 10 are respectively connected are provided as connecting parts for lifting. Further, on the lower surface of the main material 5 of the hanging scale 4, eight hanging pieces 8 are provided as connecting parts for lowering. These hanging pieces 7, 8 are, for example, semi-circular plates provided with through holes, and are fixed to the main material 5 by welding or the like.

[0014] The hanging piece 8 provided on the lower surface of the main material 5 is connected to the hanging piece 2a provided on the suspended load 2 via a suspension rope 9 such as a wire rope. The length of the suspension rope 9 and the position of the hanging piece 2a are set so that the posture of the suspended load 2 is the same as the posture of the hanging scale 4. In the present embodiment, the lengths of all eight suspension ropes 9 are the same, and the arrangement interval of the hanging pieces 2a is the same as the arrangement interval of the hanging pieces 8 of the hanging scale 4.

[0015] Hereinafter, for convenience of explanation, an axis parallel to the short side direction of the hanging scale 4, that is, the longitudinal direction of the connecting member 6 is defined as the X-axis, an axis parallel to the longitudinal direction of the hanging scale 4, that is, the longitudinal direction of the main material 5 is defined as the Y-axis, and an axis parallel to the vertical axis is defined as the Z-axis. The X-axis, Y-axis, and Z-axis are axes orthogonal to each other, and the XY plane orthogonal to the Z-axis is a horizontal plane.

[0016] Further, when the plane formed by the main material 5 and the connecting member 6 of the hanging scale 4 having the above shape is parallel to the XY plane (horizontal plane), that is, when the plane including all the first load points P1 is parallel to the XY plane (horizontal plane), the posture of the hanging scale 4 and the posture of the suspended load 2 suspended from the hanging scale 4 are referred to as "horizontal postures".

[0017] Each of the four hanging pieces 7 provided at four positions of the hanging scale 4 is arranged so that the distances from the center of gravity of the hanging scale 4 are the same. As shown in FIG. 1, the interval between the hanging pieces 7 in the X-axis direction, that is, the interval between the first load points P1 in the X-axis direction is set to a predetermined first length Lx, and the interval between the hanging pieces 7 in the Y-axis direction, that is, the interval between the first load points P1 in the Y-axis direction is set to a predetermined second length Ly.

[0018] The suspension device 100 according to this embodiment has, as four suspension cables 10, a first suspension cable 10a, a second suspension cable 10b, a third suspension cable 10c, and a fourth suspension cable 10d. These suspension cables 10 are load chains that are paid out (lowered) or wound in (lifted) by a chain block 20 described later, and as shown in FIG. 2, a suspension tool 11 such as a suspension hook is provided at the lower end thereof. That is, the suspension cable 10 is connected to each suspension piece 7 provided on the suspension balance 4 via the suspension tool 11. Note that a shackle or a wire rope may be separately used to connect the suspension cable 10 and the suspension piece 7.

[0019] In FIG. 1, among the first load points P1, the first load point where the load of the suspension load 2 acts on the first suspension cable 10a by connecting the first suspension cable 10a to the suspension balance 4 is denoted by reference sign P1a, and the second suspension cable 10b is connected to the suspension balance 4. Thus, the first load point where the load of the suspension load 2 acts on the second suspension cable 10b is denoted by reference sign P1b, and the third suspension cable 10c is connected to the suspension balance 4. Thus, the first load point where the load of the suspension load 2 acts on the third suspension cable 10c is denoted by reference sign P1c, and the fourth suspension cable 10d is connected to the suspension balance 4. Thus, the first load point where the load of the suspension load 2 acts on the fourth suspension cable 10d is denoted by reference sign P1d, respectively.

[0020] Corresponding to the four suspension cables 10, the chain block 20 is provided with four: a first chain block 20a for paying out or winding in the first suspension cable 10a, a second chain block 20b for paying out or winding in the second suspension cable 10b, a third chain block 20c for paying out or winding in the third suspension cable 10c, and a fourth chain block 20d for paying out or winding in the fourth suspension cable 10d. As shown in FIG. 1, these chain blocks 20 are housed in a housing 28 and unitized.

[0021] As shown in FIG. 2, each chain block 20 includes a main body 21 that houses various mechanisms such as a load sheave (not shown) with which the suspension cable 10 (load chain) meshes and a brake (not shown) provided to hold the load sheave in a stopped state, an electric motor 22 that rotationally drives the load sheave, a bucket 23 that stores the suspension cable 10, and a hanger 24 that connects the main body 21 to a support member 25.

[0022] The chain block 20 configured as described above functions as a distance adjustment device that rotationally drives the load sheave by the electric motor 22 and adjusts the distance between a first load point P1 at which the load of the suspended load 2 acts on the suspension cable 10 and a second load point P2 at which the load of the suspended load 2 acts on the hanger 1 via the suspension cable 10 by adjusting the length of the suspension cable 10 that is paid out. Note that the rotation direction and rotation speed of the electric motor 22 are detected by an encoder (not shown) and transmitted to a control device 40.

[0023] Further, each chain block 20 is suspended from a common support member 25 via a hanger 24 so as to be swingable in all directions. The support member 25 from which each chain block 20 is suspended in this manner is connected to a crane hanger 1 via a hanger 26. As a result, the load of the suspended load 2 acting on each suspension cable 10 acts on the crane hanger 1 via the suspension cable 10, the main body 21, the hanger 24, the support member 25, and the hanger 26.

[0024] Each hanger 24 connected to the support member 25 is provided with a load cell 32 that can detect the load of the suspended load 2 acting on each suspension cable 10, that is, the load acting on each chain block 20. Further, the hanger 26 connected to the hanger 1 is provided with a load cell 34 that can detect the total load of the load acting on the hanger 1, that is, the load acting on each chain block 20 and the load corresponding to the weight of the hoisting device 100. The detection values of the load cells 32 and 34 are transmitted to the control device 40.

[0025] In addition, the suspension device 100 is provided with red lights 36a to 36d that are lit according to the loads detected by the respective load cells 32 and 34. The red lights 36a to 36d are arranged corresponding to the respective chain blocks 20. Specifically, as shown in FIG. 1, they are attached to the four lower corners of the housing 28 in which the chain block 20 is accommodated.

[0026] The lighting of the red lights 36a to 36d is controlled by the control device 40. For example, the red light 36a provided corresponding to the first chain block 20a blinks when the load detected by the load cell 32 provided in the first chain block 20a approaches the allowable load of the first chain block 20a, and lights up when the allowable load is exceeded. Also, when the load detected by the load cell 34 capable of detecting the load acting on the crane's lifting tool 1 approaches the allowable load of the suspension device 100, all the red lights 36a to 36d blink, and when the load detected by the load cell 34 exceeds the allowable load of the suspension device 100, all the red lights 36a to 36d light up.

[0027] By lighting or blinking the red lights 36a to 36d downward in this way, it is possible to quickly warn an operator or a slinger worker working below the suspension device 100 that the load acting on the chain block 20 or the load acting on the suspension device 100 is in an overload state.

[0028] Note that the load of the suspended load 2 acting on each suspension cable 10 may be estimated based on the current value supplied to the electric motor 22 of the chain block 20 instead of being detected by the load cell 32, that is, the electric power required to wind up each suspension cable 10 on which the load of the suspended load 2 acts. When the load of the suspended load 2 acting on each suspension cable 10 is estimated in this way, it is not necessary to provide a load cell 32 on each lifting tool 24 connected to the support member 25, so that each chain block 20 can be arranged in the vicinity of the support member 25. As a result, the hoisting device 100 can be made compact in the height direction. However, when a certain degree of accuracy is required for determining whether or not the allowable load has been exceeded, or when it is necessary to determine whether or not each suspension cable 10 is slack as described later, it is preferable to detect the load of the suspended load 2 acting on each suspension cable 10 by the load cell 32.

[0029] The inclination angle measuring device 30 is a sensor capable of measuring inclination angles around the X-axis and Y-axis that are orthogonal to each other, and includes an inclination angle sensor that measures the first inclination angle θ1 around the X-axis with respect to the horizontal plane and an inclination angle sensor that measures the second inclination angle θ2 around the Y-axis with respect to the horizontal plane, which are integrated. The inclination angle measuring device 30 is attached to the horizontal plane of the suspension scale 4, and the measured inclination angle is transmitted to the control device 40 by wireless communication. Note that the inclination angle measuring device 30 may be composed of a first inclination angle sensor that measures the first inclination angle θ1 and a second inclination angle sensor that is arranged separately from the first inclination angle sensor and measures the second inclination angle θ2. Further, the inclination angle measuring device 30 may be attached to the horizontal plane of the suspended load 2 instead of the suspension scale 4.

[0030] The control device 40 is composed of a microcomputer including a CPU (Central Processing Unit) as an operation circuit, a storage unit such as a ROM (Read Only Memory) and a RAM (Random Access Memory), an input / output interface (I / O interface), and other peripheral circuits. The control device 40 may also be composed of a plurality of microcomputers.

[0031] In the storage unit of the control device 40, there are various programs for realizing the functions of this embodiment, such as an attitude control program for adjusting the postures of the suspended load 2 and the suspension scale 4 by controlling the operations of the respective chain blocks 20 based on the inclination angles measured by the inclination angle measuring device 30. Specifically, a program for setting target values of the rotation speed and rotation direction of the electric motor 22 based on the inclination angle, and a program for controlling the power supplied to the electric motor 22 of each chain block 20 so that the rotation speed and rotation direction of the electric motor 22 detected by the encoder follow the target values are stored.

[0032] Note that as the operation circuit, instead of or together with the CPU, an MPU (Micro Processing Unit), a DSP (Digital Signal Processor), an ASIC (application specific integrated circuit), an FPGA (Field Programmable Gate Array), etc. can be used.

[0033] The control device 40 is housed in the housing 28 together with the chain block 20. Also, in the housing 28, a battery and an inverter are housed as a power supply device for supplying power to the chain block 20. In this way, by aggregating and arranging the devices constituting the hoisting device 100, the hoisting device 100 can be made compact.

[0034] Further, the control device 40 has a wireless communication unit 41 that receives the data transmitted from the inclination angle measuring device 30 and transmits and receives data to and from an operation device 31 held by the operator.

[0035] The operating device 31 is a portable tablet terminal having a display monitor and an input device. An instruction signal for instructing the operation of the suspension device 100 is transmitted from the operating device 31 to the control device 40, and state information indicating the state of the suspension device 100, for example, the inclination state of the suspended load 2 detected by the inclination angle measuring device 30, the loads detected by the respective load cells 32, 34, the operating state of each chain block 20, the remaining battery level, etc. is transmitted from the control device 40 to the operating device 31.

[0036] The information transmitted from the control device 40 to the operating device 31 is displayed on the display monitor of the operating device 31, and the operator can confirm whether there is slack in each suspension rope 10, for example, by comparing the detected values of the respective load cells 32 displayed. Note that the inclination angle measuring device 30 and the operating device 31 may transmit and receive data to and from the control device 40 by wired communication instead of wireless communication. Further, as a device for transmitting and receiving data with the control device 40, instead of or in addition to the operating device 31, a remote control without an attached display monitor or a monitor device without an attached input device may be provided.

[0037] Here, generally, in a series of hoisting operations of lifting the suspended load 2 by a crane and lowering it to a predetermined location, from the viewpoint of safety, it is required to always keep the suspended load 2 in a horizontal posture.

[0038] To make the suspended load 2 horizontal, for example, after adjusting the inclination in one direction of the suspended load 2, it is conceivable to make the suspended load 2 horizontal by adjusting the inclination in another direction orthogonal thereto.

[0039] However, when the adjustment for making the suspended load 2 horizontal is performed in two steps in this way, if load sway occurs in the adjustment performed first, the subsequent adjustment cannot be performed until the load sway sufficiently converges. For this reason, it takes time to make the suspended load 2 horizontal, and as a result, the time required for the hoisting operation may become long.

[0040] Therefore, in the present embodiment, one reference sling is selected from the slings 10, and all the other chain blocks 20 except the chain block 20 provided on the reference sling are simultaneously operated to adjust the posture of the suspended load 2, so that the posture of the suspended load 2 is made horizontal in a short time without causing load swing.

[0041] Next, with reference to FIGS. 3 to 5, a method for adjusting the posture of the suspended load 2 by the suspension device 100 having the above configuration will be described. FIG. 3 is a diagram conceptually showing a state in which a height difference occurs at each first load point P1 due to the inclination of the suspended load 2, FIG. 4 is a flowchart for explaining the procedure for adjusting the posture of the suspended load 2, and FIG. 5 is a flowchart showing a part of the processing content of the flowchart of FIG. 4.

[0042] Hereinafter, as shown in FIG. 3, when the suspended load 2 is inclined at a first inclination angle θ1 about the X axis with respect to the horizontal plane and inclined at a second inclination angle θ2 about the Y axis with respect to the horizontal plane, a procedure for making the posture of the suspended load 2 horizontal will be described. As described above, the lengths between the first load point P1a and the first load point P1c and between the first load point P1b and the first load point P1d are the first length Lx, and the lengths between the first load point P1a and the first load point P1b and between the first load point P1c and the first load point P1d are the second length Ly.

[0043] First, in step S11 (inclination angle acquisition step), the control device 40 acquires the current first inclination angle θ1 and the second inclination angle θ2 detected by the inclination angle measuring device 30 as parameters indicating the current inclination state of the suspended load 2.

[0044] Subsequently, in step S12 (operation necessity determination step), the control device 40 determines whether the acquired current inclination angle is greater than a non-operation inclination angle θs preset as an angle for making the chain block 20 in a non-operation state.

[0045] When the magnitudes of the first inclination angle θ1 and the second inclination angle θ2, which are the current inclination angles, are of a certain magnitude and the posture of the suspended load 2 is inclined to such an extent that it cannot be said to be in a horizontal posture, it is necessary to operate the chain block 20 to bring the posture of the suspended load 2 closer to the horizontal posture.

[0046] On the other hand, when the magnitudes of the first inclination angle θ1 and the second inclination angle θ2, which are the current inclination angles, are near zero degrees, that is, when the posture of the suspended load 2 is substantially in a horizontal posture, if the chain block 20 is operated, the posture of the suspended load 2 may rather be inclined.

[0047] Therefore, in step S12 (operation necessity determination step), it is determined based on the magnitudes of the current first inclination angle θ1 and the second inclination angle θ2 whether the posture of the suspended load 2 is in a situation where the chain block 20 should be operated, that is, whether the posture of the suspended load 2 is in a posture that is acceptable as a horizontal posture.

[0048] In step S12, when the magnitudes of the current first inclination angle θ1 and the second inclination angle θ2 are larger than the non-operation inclination angle θs, it is considered that the situation is such that the chain block 20 should be operated, and the process proceeds to step S13. Note that the non-operation inclination angle θs serving as the determination criterion is set separately for the first inclination angle θ1 and the second inclination angle θ2, and when both or either one of the first inclination angle θ1 and the second inclination angle θ2 is larger than the non-operation inclination angle θs, the process proceeds to step S13.

[0049] In the subsequent step S13 (height determination step), the control device 40 determines the height ranking in the vertical direction of each first load point P1 based on the acquired first inclination angle θ1 and second inclination angle θ2.

[0050] Specifically, among a plurality of first load points P1, when one point selected in advance is set as the origin, the inclination angle that is the elevation angle when viewed from this origin is set as a positive value, and the inclination angle that is the depression angle is set as a negative value, the height of each first load point P1 in the vertical direction is determined according to whether the values of the obtained first inclination angle θ1 and second inclination angle θ2 are positive or negative, respectively.

[0051] For example, when the first load point P1a of the first suspension cable 10a shown in FIG. 3 is set as the origin, if the values of the first inclination angle θ1 and the second inclination angle θ2 are both positive, the first load point P1a of the first suspension cable 10a is the lowest, and the first load point P1d of the fourth suspension cable 10d is the highest.

[0052] On the other hand, if the values of the first inclination angle θ1 and the second inclination angle θ2 are both negative, the first load point P1a of the first suspension cable 10a is the highest, and the first load point P1d of the fourth suspension cable 10d is the lowest.

[0053] Also, if the value of the first inclination angle θ1 is positive and the value of the second inclination angle θ2 is negative, the first load point P1c of the third suspension cable 10c is the lowest, and the first load point P1b of the second suspension cable 10b is the highest. Further, if the value of the first inclination angle θ1 is negative and the value of the second inclination angle θ2 is positive, the first load point P1b of the second suspension cable 10b is the lowest, and the first load point P1c of the third suspension cable 10c is the highest.

[0054] Therefore, according to this height determination method, in the example shown in FIG. 3, since the values of the first inclination angle θ1 and the second inclination angle θ2 are both positive, the first load point P1a of the first suspension cable 10a is the lowest, the first load point P1d of the fourth suspension cable 10d is the highest, and the first load points P1b of the second suspension cable 10b and P1c of the third suspension cable 10c are determined to be located between them. Note that the method for determining the height of the plurality of first load points P1 is not limited to the above method, and any method may be used as long as the height of the plurality of first load points P1 can be determined. For example, a beacon transmitter may be provided around each first load point P1, and the height of each first load point P1 may be determined based on the signals transmitted from these transmitters.

[0055] When the ranking of the heights of the first load points P1 is determined, the process proceeds to step S14 (reference selection step), and based on predetermined conditions, a reference suspension cable is selected. Hereinafter, the case where the selection condition is that among the suspension cables 10, the suspension cable 10 with the lowest height in the vertical direction of the first load point P1 will be described. The selection conditions are preset in consideration of quickly bringing the suspended load 2 into a horizontal posture without causing load swing or slack in the suspension cables 10.

[0056] As described above, in the example shown in FIG. 3, it is determined that the height of the first load point P1a of the first suspension cable 10a is the lowest. Therefore, the first suspension cable 10a is selected as the reference suspension cable.

[0057] After this step, the operation of the first chain block 20a that pays out or takes in the first suspension cable 10a selected as the reference suspension cable is prohibited. In other words, the adjustment of the posture of the suspended load 2 is performed by operating all other chain blocks 20b, 20c, 20d except the first chain block 20a.

[0058] Subsequently, the process proceeds to step S15 (operating speed setting step), and the operating speeds of the other chain blocks 20b, 20c, 20d except the first chain block 20a are set, that is, the speeds at which the other suspension cables 10b, 10c, 10d except the first suspension cable 10a are paid out are set. The method for setting the operating speed performed in step S15 will be described with reference to the flowchart shown in FIG. 5 and FIG. 3.

[0059] In order to set the operating speeds of the respective chain blocks 20b, 20c, and 20d, first, in step S21 (height difference calculation step), the height differences between the height in the vertical direction of the first load point P1a of the first suspension cable 10a selected as the reference suspension cable and the heights in the vertical direction of the other first load points P1b, P1c, and P1d are calculated respectively. Note that, as shown in FIG. 3, the height difference means the height in the vertical direction from the reference horizontal plane PL1 to each of the first load points P1b, P1c, and P1d when the horizontal plane including the first load point P1a of the first suspension cable 10a is taken as the reference horizontal plane PL1.

[0060] As shown in FIG. 3, due to the load 2 being tilted by the first tilt angle θ1 around the X-axis, the first load point P1b of the second suspension cable 10b is higher in height in the vertical direction than the first load point P1a. The first height D1, which is the height difference between the first load point P1b of the second suspension cable 10b at this time and the first load point P1a of the first suspension cable 10a, is obtained by the following formula (1). D1 = Ly·sinθ1 ···(1)

[0061] Also, due to the load 2 being tilted by the second tilt angle θ2 around the Y-axis, the first load point P1c of the third suspension cable 10c is higher in height in the vertical direction than the first load point P1a. The second height D2, which is the height difference between the first load point P1c of the third suspension cable 10c at this time and the first load point P1a of the first suspension cable 10a, is obtained by the following formula (2). D2 = Lx·sinθ2 ···(2)

[0062] And, due to the load 2 being tilted by the first tilt angle θ1 around the X-axis and tilted by the second tilt angle θ2 around the Y-axis, the first load point P1d of the fourth suspension cable 10d is the highest in height in the vertical direction. The third height D3, which is the height difference between the first load point P1d of the fourth suspension cable 10d at this time and the first load point P1a of the first suspension cable 10a, is obtained by the following formula (3). D3 = D1 + D2 ···(3)

[0063] When the respective heights D1, D2, and D3 are calculated, the process proceeds to step S22 (deceleration start determination step), and it is determined whether the current inclination angle is greater than a deceleration start inclination angle θd that is preset as the angle at which deceleration starts.

[0064] When the magnitudes of the first inclination angle θ1 and the second inclination angle θ2, which are the current inclination angles, are relatively large, that is, when the inclination of the suspended load 2 is relatively large, it is preferable to make the operating speeds of the chain blocks 20b, 20c, and 20d as fast as possible to quickly bring the posture of the suspended load 2 closer to the horizontal posture.

[0065] On the other hand, when the magnitudes of the first inclination angle θ1 and the second inclination angle θ2, which are the current inclination angles, are relatively small, that is, when the posture of the suspended load 2 is in a state close to the horizontal posture, if the operating speeds of the chain blocks 20b, 20c, and 20d are too fast, when the posture of the suspended load 2 becomes horizontal, the operation of the chain blocks 20b, 20c, and 20d will suddenly stop, resulting in load sway, or the stop of the operation of the chain blocks 20b, 20c, and 20d may not be in time, and there is a risk that the posture of the suspended load 2 will exceed the horizontal posture and tilt again.

[0066] Therefore, in step S22 (deceleration start determination step), based on the magnitudes of the current first inclination angle θ1 and the second inclination angle θ2, it is determined whether the state of the suspended load 2 is a situation where the operating speeds of the chain blocks 20b, 20c, and 20d should be increased, or a situation where the operating speeds of the chain blocks 20b, 20c, and 20d should be decreased. Note that the deceleration start inclination angle θd is a value greater than the above-described non-operating inclination angle θs.

[0067] In step S22, when the magnitudes of the current first tilt angle θ1 and second tilt angle θ2 are greater than the deceleration start tilt angle θd, it is necessary to quickly bring the posture of the suspended load 2 closer to the horizontal posture. Therefore, the process proceeds to step S23, and the operating speed V4 of the fourth chain block 20d that pays out the fourth suspension cable 10d, which is the suspension cable 10 with the highest first load point P1, is set to the maximum speed Vmax.

[0068] The maximum speed Vmax is the maximum payout speed at which the suspension cable 10 can be paid out by the chain block 20. Note that the deceleration start tilt angle θd serving as the determination criterion is set separately for the first tilt angle θ1 and the second tilt angle θ2, and when both the first tilt angle θ1 and the second tilt angle θ2 are greater than the deceleration start tilt angle θd, the process proceeds to step S23.

[0069] In the subsequent step S24, the operating speeds V2 and V3 of the second chain block 20b and the third chain block 20c, which are chain blocks 20 other than the fourth chain block 20d with the operating speed V4 set, are set according to the height difference calculated in step S21.

[0070] In this step, when the first load points P1b of the second suspension cable 10b, the first load points P1c of the third suspension cable 10c, and the first load points P1d of the fourth suspension cable 10d are hypothetically moved toward the reference horizontal plane PL1 at the set operating speeds V2, V3, and V4 respectively, the operating speeds V2 and V3 of the second chain block 20b and the third chain block 20c are set so that the first load points P1b, P1c, and P1d reach the reference horizontal plane PL1 simultaneously.

[0071] In other words, when the first load point P1d of the fourth suspension cable 10d is moved toward the reference horizontal plane PL1 at the operating speed V4 (Vmax), the operating speeds V2 and V3 of the second chain block 20b and the third chain block 20c are set so that the first load point P1b of the second suspension cable 10b and the first load point P1c of the third suspension cable 10c reach the reference horizontal plane PL1 at the same timing as the first load point P1d reaches the reference horizontal plane PL1.

[0072] Specifically, the operating speed V2 of the second chain block 20b is obtained by multiplying the ratio of the first height D1 to the third height D3, which corresponds to the ratio of the length of the second sling 10b paid out to the length of the fourth sling 10d paid out, as shown in the following formula (4), by the maximum speed Vmax, which is the operating speed V4 of the fourth chain block 20d. V2 = (D1 / D3) * Vmax ···(4)

[0073] Similarly, the operating speed V3 of the third chain block 20c is obtained by multiplying the ratio of the second height D2 to the third height D3, which corresponds to the ratio of the length of the third sling 10c paid out to the length of the fourth sling 10d paid out, as shown in the following formula (5), by the maximum speed Vmax, which is the operating speed V4 of the fourth chain block 20d. V3 = (D2 / D3) * Vmax ···(5)

[0074] By paying out the second sling 10b and the third sling 10c at the thus set operating speeds V2 and V3, the first load points P1b of the second sling 10b and P1c of the third sling 10c move toward the reference horizontal plane PL1 at a relatively high speed as if they reach the reference horizontal plane PL1 at the same timing as the first load point P1d of the fourth sling 10d paid out at the operating speed V4 (maximum speed Vmax).

[0075] On the other hand, in step S22, when the magnitudes of the current first inclination angle θ1 and second inclination angle θ2 are equal to or less than the deceleration start inclination angle θd, assuming that the posture of the suspended load 2 is in a state close to the horizontal posture, the process proceeds to step S25, and the operating speed V4 of the fourth chain block 20d that pays out the fourth sling 10d, which is the sling 10 with the highest first load point P1, is set to the deceleration speed Vd.

[0076] During deceleration, the speed Vd is a speed preset experimentally, for example, a speed about one-tenth of the maximum speed Vmax. Note that the deceleration start inclination angle θd serving as a determination criterion is set separately for the first inclination angle θ1 and the second inclination angle θ2. When both or either one of the first inclination angle θ1 and the second inclination angle θ2 becomes less than or equal to the deceleration start inclination angle θd, the process proceeds to step S25.

[0077] In the subsequent step S26, in the same manner as in step S24, the operating speeds V2 and V3 of the second chain block 20b and the third chain block 20c, which are chain blocks 20 other than the fourth chain block 20d for which the operating speed V4 is set, are set according to the level difference calculated in step S21, respectively.

[0078] Specifically, the operating speed V2 of the second chain block 20b is obtained by multiplying the deceleration speed Vd, which is the operating speed V4 of the fourth chain block 20d, by the ratio of the first height D1 to the third height D3, which corresponds to the ratio of the length of the second sling 10b paid out to the length of the fourth sling 10d paid out, as shown in the following formula (6). V2 = (D1 / D3) * Vd ···(6)

[0079] Similarly, the operating speed V3 of the third chain block 20c is obtained by multiplying the deceleration speed Vd, which is the operating speed V4 of the fourth chain block 20d, by the ratio of the second height D2 to the third height D3, which corresponds to the ratio of the length of the third sling 10c paid out to the length of the fourth sling 10d paid out, as shown in the following formula (7). V3 = (D2 / D3) * Vd ···(7)

[0080] By paying out the second suspension cable 10b and the third suspension cable 10c at the operating speeds V2 and V3 set in this way, the first load points P1b of the second suspension cable 10b and P1c of the third suspension cable 10c move toward the reference horizontal plane PL1 at a relatively slow speed as if they reach the reference horizontal plane PL1 at the same timing as the first load point P1d of the fourth suspension cable 10d paid out at the operating speed V4 (deceleration speed Vd).

[0081] In step S15, when the setting of the operating speeds V2, V3, and V4 is completed, the process proceeds to step S16 (posture adjustment process), and each of the chain blocks 20b, 20c, and 20d except the first chain block 20a is simultaneously controlled by the control device 40 so as to pay out the respective suspension cables 10b, 10c, and 10d at the set operating speeds V2, V3, and V4.

[0082] In this way, by simultaneously paying out the other suspension cables 10b, 10c, and 10d except the first suspension cable 10a at the set operating speeds V2, V3, and V4, the other first load points P1b, P1c, and P1d except the first load point P1a of the first suspension cable 10a approach the reference horizontal plane PL1 including the first load point P1a simultaneously. As a result, the posture of the suspension scale 4 and the posture of the suspended load 2 suspended from the suspension scale 4 are adjusted to approach the horizontal posture.

[0083] If the magnitudes of the operating speeds V2, V3, and V4 set in step S15 change abruptly, for example, when the operating speed V4 is changed from the maximum speed Vmax to the deceleration speed Vd, if the payout target speed of the chain block 20 is simply switched, there is a risk of load swing due to the reaction caused by the abrupt deceleration. Therefore, when the operating speeds V2, V3, and V4 are changed in step S15, the actual speed at which the suspension cable 10 is paid out in the chain block 20 is gradually changed over a preset speed transition time, for example, about 0.5 seconds.

[0084] After operating each of the chain blocks 20b, 20c, and 20d except the first chain block 20a at the set operating speeds V2, V3, and V4 in this way, the process returns to step S11, and the current inclination angle is acquired again.

[0085] On the other hand, in step S12, when the magnitudes of the current first inclination angle θ1 and second inclination angle θ2 are equal to or less than the non-operating inclination angle θs, it is determined that the situation is not suitable for operating the chain block 20, and the process proceeds to step S17. Note that the non-operating inclination angle θs serving as the determination criterion is set separately for the first inclination angle θ1 and the second inclination angle θ2, and when both the first inclination angle θ1 and the second inclination angle θ2 are equal to or less than the non-operating inclination angle θs, the process proceeds to step S17.

[0086] In step S17 (operation stop step), since it is determined that the posture of the suspended load 2 is almost horizontal, the operation of all the chain blocks 20 is stopped.

[0087] Before reaching step S17, even if any of the chain blocks 20 are not operating or have operated through steps 13 to 16 as described above, the operating speed V4 of the fourth chain block 20d is decelerated from the maximum speed Vmax to the deceleration speed Vd, and the operating speeds V2 and V3 of the second chain block 20b and the third chain block 20c are also decelerated to speeds according to the deceleration speed Vd.

[0088] Therefore, in step S17 (operation stop step), when any of the chain blocks 20 are not operating, that state is maintained, and when the chain blocks 20b, 20c, and 20d are operating as described above, over a preset deceleration stop time, for example, about 0.1 seconds, the operating speed V4 of the fourth chain block 20d is gradually decelerated until it becomes zero from the deceleration speed Vd, and the operating speeds V2 and V3 of the second chain block 20b and the third chain block 20c are gradually decelerated until they become zero from the speeds according to the deceleration speed Vd, respectively.

[0089] Through these series of steps, the adjustment of the posture of the suspended load 2 by the suspension device 100 is completed, and the posture of the suspended load 2 becomes a horizontal posture. The arithmetic processing from step S11 to step S16 is performed every fixed processing period, for example, every 20 msec, and the operating speed of the chain block 20 will be changed according to the detected value of the inclination angle measuring device 30 indicating the current inclination state of the suspended load 2.

[0090] According to the suspension device 100 with the above configuration, the adjustment of the posture of the suspended load 2 is carried out by simultaneously operating all the chain blocks 20 except the chain block 20 provided on the reference suspension cable, that is, by fixing one of the plurality of first load points P1 and simultaneously moving all the other first load points P1. This enables rapid adjustment.

[0091] Therefore, compared with the case of adjusting the posture of the suspended load 2 by two-stage adjustment, where the inclination in one direction of the suspended load 2 is adjusted first and then the inclination in the other direction orthogonal to this is adjusted, the posture of the suspended load 2 can be made horizontal in a short time without causing load swing or slackening of the suspension cables 10.

[0092] Also, by setting the reference suspension cable on which the chain block 20 does not operate as the suspension cable 10 with the lowest first load point P1, all the plurality of chain blocks 20 that operate simultaneously will operate so as to pay out the suspension cable 10. That is, it is possible to avoid a mixture of a chain block 20 that operates so as to take in the suspension cable 10 and a chain block 20 that operates so as to pay out the suspension cable 10.

[0093] Therefore, since the moving directions of the first load points P1 other than the fixed first load point P1 in the vertical direction are all downward, it is possible to surely suppress the occurrence of load swing in the process of adjusting the posture of the suspended load 2 compared with the case where the moving directions of the first load point P1 in the vertical direction are different between upward and downward.

[0094] Also, by setting the reference suspension cable that does not operate the chain block 20 as the suspension cable 10 where the first load point P1 is the lowest, among the plurality of chain blocks 20 that operate simultaneously, each suspension cable 10 will operate such that it is pulled out by the weight of the suspended load 2. Therefore, compared with the case of operating the chain block 20 so as to wind in the suspension cable 10 against the weight of the suspended load 2, the power consumed by the electric motor 22 of the chain block 20 can be reduced.

[0095] In addition, since the load of the suspended load 2 always acts on each suspension cable 10, it is almost possible to avoid slack in each suspension cable 10. However, in the suspension device 100 with the above configuration, the tension acting on each suspension cable 10 is detected by the load cell 32, and the tension acting on each suspension cable 10 changes by operating the chain block 20. Therefore, even if slack occurs in any one of the suspension cables 10, the slack of the suspension cable 10 can be easily eliminated by operating the chain block 20 according to the detection value of the load cell 32.

[0096] According to the above embodiment, the following effects can be obtained.

[0097] In the suspension device 100 with the above configuration, the adjustment of the posture of the suspended load 2 is quickly performed by simultaneously operating all the chain blocks 20 except the chain block 20 provided on the reference suspension cable, that is, by fixing one of the first load points P1 among the plurality of first load points P1 and simultaneously moving all the other first load points P1.

[0098] Therefore, compared with the case of adjusting the posture of the suspended load 2 by two-stage adjustment in which the inclination in one direction of the suspended load 2 is adjusted and then the inclination in the other direction orthogonal to this is adjusted, the posture of the suspended load 2 can be made horizontal in a short time without causing load swing or slack in the suspension cable 10. As a result, the time required for the heavy lifting operation can be shortened.

[0099] In addition, the following modified examples are also within the scope of the present invention, and it is also possible to combine the configurations shown in the modified examples with the configurations described in the above-described embodiments, or to combine the configurations described in the following different modified examples with each other.

[0100] In the above embodiment, the selection condition for selecting the reference suspension cable is the condition that among the suspension cables 10, the suspension cable 10 with the lowest height in the vertical direction of the first load point P1. Instead of this, the selection condition may be the condition that among the suspension cables 10, the suspension cable 10 with the highest height in the vertical direction of the first load point P1. When the selection condition for selecting the reference suspension cable is such a condition, in the example shown in FIG. 3, the fourth suspension cable 10d with the highest height of the first load point P1d is selected as the reference suspension cable. And in this case, the adjustment of the posture of the suspended load 2 is performed by operating all the other chain blocks 20a, 20b, 20c except the fourth chain block 20d.

[0101] When the reference suspension cable that does not operate the chain block 20 in this way is the suspension cable 10 with the highest first load point P1, the plurality of chain blocks 20 that operate simultaneously will all operate so as to feed in the suspension cable 10. That is, it is possible to avoid the mixture of the chain block 20 that operates so as to feed in the suspension cable 10 and the chain block 20 that operates so as to pay out the suspension cable 10.

[0102] For this reason, since the moving directions in the vertical direction of the first load point P1 other than the fixed first load point P1 are all upward, compared with the case where the moving direction of the first load point P1 in the vertical direction is different between upward and downward, it is possible to surely suppress the occurrence of load swing in the process of adjusting the posture of the suspended load 2.

[0103] In the above-described embodiment, the selection condition for selecting the reference suspension cable is the condition that among the suspension cables 10, the suspension cable 10 with the lowest height in the vertical direction of the first load point P1 is selected. Instead of this, the selection condition may be the condition that among the suspension cables 10, the suspension cable 10 is between the suspension cable 10 with the highest height and the suspension cable 10 with the lowest height in the vertical direction of the first load point P1. For example, as in the modification shown in FIG. 6, the second suspension cable 10b in which the height of the first load point P1b is between the highest first load point P1d and the lowest first load point P1a may be selected as the reference suspension cable.

[0104] In this case, the adjustment of the posture of the suspended load 2 is performed by fixing only the first load point P1b and simultaneously moving all the other first load points P1a, P1c, P1d toward the reference horizontal plane PL1 including the first load point P1b.

[0105] When the reference horizontal plane PL1 is set as the horizontal plane including the first load point P1 between the highest first load point P1d and the lowest first load point P1a in this way, compared with the case where the reference horizontal plane PL1 is set as the horizontal plane including the highest first load point P1d or the case where the reference horizontal plane PL1 is set as the horizontal plane including the lowest first load point P1a as in the above-described embodiment, the distance for moving each first load point P1 in the vertical direction toward the reference horizontal plane PL1 in order to make the posture of the suspended load 2 a horizontal posture, that is, the length of the suspension cable 10 paid out or wound in each chain block 20 becomes shorter.

[0106] Specifically, as shown in FIG. 6, the moving distance of the first load point P1a is the same distance as the first height D1, the moving distance of the first load point P1c is the distance obtained by subtracting the first height D1 from the second height D2 (the fourth height D4), and the moving distance of the first load point P1d is the same distance as the second height D2. All of the moving distances are shorter than the third height D3, which is the longest moving distance in the above-described embodiment.

[0107] Therefore, in this modification, the posture of the suspended load 2 can be made a horizontal posture in a shorter time than in the above-described embodiment.

[0108] In addition, in order to make the posture of the suspended load 2 horizontal in a short time, as in the reference example shown in FIG. 7, without fixing any of the first load points P1, the reference horizontal plane PL1 is set to the intermediate position between the highest first load point P1d and the lowest first load point P1a, and all the first load points P1 are moved toward the reference horizontal plane PL1, that is, it is conceivable to operate all the chain blocks 20 simultaneously.

[0109] However, in this reference example, while some of the first load points P1a, P1b move upward in the vertical direction, the other first load points P1c, P1d move downward in the vertical direction. When there is no first load point P1 that is fixed and serves as a reference and the moving directions of the first load points P1 are different from each other, load sway is likely to occur in the process of adjusting the posture of the suspended load 2, and as a result, the time required to make the posture of the suspended load 2 horizontal may become long.

[0110] Therefore, in order to make the posture of the suspended load 2 horizontal in a short time, as in the above embodiment and the above modification example, it is advantageous to fix one of the first load points P1 among the plurality of first load points P1 and simultaneously move all the other first load points P1 toward the reference horizontal plane PL1 that includes the fixed first load point P1.

[0111] Further, in the above embodiment, the operating speed of each chain block 20 is switched stepwise to the speed corresponding to the maximum speed Vmax and the speed corresponding to the speed Vd during deceleration according to the inclination angle. Instead of this, the operating speed of each chain block 20 may be continuously changed according to the magnitude of the third height D3 with the largest height difference. For example, while the magnitude of the third height D3 is equal to or greater than a predetermined threshold, the operating speed of the chain block 20 that pays out the suspension cable 10 with the highest first load point P1 is set to the maximum speed Vmax, and when the magnitude of the third height D3 is less than the predetermined threshold, the operating speed of the chain block 20 may be gradually decreased as the magnitude of the third height D3 decreases.

[0112] In the above-described embodiment, a chain block 20 is used as a distance adjustment device for adjusting the distance between a first load point P1 where the load of the suspended load 2 acts on the suspension cable 10 and a second load point P2 where the load of the suspended load 2 acts on the lifting tool 1 via the suspension cable 10. The distance adjustment device is not limited to the chain block 20, and any device may be used as long as it can adjust the distance between the first load point P1 and the second load point P2. For example, a hydraulic cylinder, an electric cylinder, a winch, or the like may be used as the distance adjustment device. Further, as the suspension cable 10, a wire rope, a chain sling, a belt sling, a round sling, or the like may be used.

[0113] In the above-described embodiment, the case where there are four suspension cables 10 has been described. However, the number of suspension cables 10 may be four or more, for example, six. In this case as well, a chain block (distance adjustment device) 20 is provided for all the suspension cables 10.

[0114] In the above-described embodiment, a battery for supplying power to the chain block 20 and a control device 40 for controlling the operation of the chain block 20 are housed in the housing 28 together with the chain block 20. Alternatively, the battery and the control device 40 may be arranged at a location separate from the lifting device 100.

[0115] In the above-described embodiment, for example, the comparison between the current inclination angle and the threshold value performed in step S22 is carried out after a predetermined step has been executed after the current inclination angle is acquired in step S11. Alternatively, the order of the steps shown in FIGS. 4 and 5 can be appropriately interchanged. For example, the comparison performed in step S22 may be carried out immediately after step S11.

[0116] The embodiments of the present invention have been described above. However, the above embodiments merely show a part of the application examples of the present invention, and are not intended to limit the technical scope of the present invention to the specific configurations of the above embodiments.

Description of Reference Numerals

[0117] 100 ··· Hoisting device 1 ··· Hoisting tool 2 ··· Hoisted load 4 ··· Hoisting balance 10(10a, 10b, 10c, 10d) ··· Hoisting ropes 20(20a, 20b, 20c, 20d) ··· Chain block (distance adjustment device) 30 ··· Inclination measuring device 40 ··· Control device P1(P1a, P1b, P1c, P1d) ··· First load point P2 ··· Second load point θ1 ··· First inclination angle (inclination angle) θ2 ··· Second inclination angle (inclination angle)

Claims

1. Four or more suspension ropes extending from the lifting tackle of the crane towards the suspended load, A distance adjustment device provided for each of the suspension ropes to adjust the distance between a first load point at which the load of the suspended load acts on the suspension rope and a second load point at which the load of the suspended load acts on the lifting tackle via the suspension rope, An inclination angle measuring device for measuring the inclination angle of the suspended load with respect to the horizontal plane, A control device for adjusting the posture of the suspended load by controlling the distance adjustment device based on the inclination angle measured by the inclination angle measuring device, comprising: The control device is configured to: Select one reference suspension rope from among the suspension ropes based on the height of a plurality of the first load points in the vertical direction, In the state where the suspended load is suspended, operate all the other distance adjustment devices except the distance adjustment device provided on the reference suspension rope simultaneously to adjust the posture of the suspended load. A lifting device.

2. The control device selects the suspension rope with the highest or lowest height of the first load point in the vertical direction as the reference suspension rope. The lifting device according to claim 1.

3. The control device is configured to: Calculate the height differences between the first load point of the reference suspension rope and the first load points of the suspension ropes other than the reference suspension rope, respectively, Set the operating speeds of the distance adjustment devices that operate to adjust the posture of the suspended load respectively based on the calculated height differences. The lifting device according to claim 1 or 2.

4. The load of the suspended load acts on the suspension rope via a load balance. The lifting device according to any one of claims 1 to 3.

5. Four or more suspension ropes extending from the lifting tackle of the crane toward the suspended load, a distance adjustment device provided for each of the suspension ropes to adjust the distance between a first load point at which the load of the suspended load acts on the suspension rope and a second load point at which the load of the suspended load acts on the lifting tackle via the suspension rope, and an inclination angle measuring device for measuring the inclination angle of the suspended load with respect to the horizontal plane. A suspended load attitude adjustment method for adjusting the attitude of the suspended load by controlling the distance adjustment device based on the inclination angle measured by the inclination angle measuring device, A reference selection step of selecting one reference suspension rope from among the suspension ropes based on the height of the plurality of first load points in the vertical direction, An attitude adjustment step of simultaneously operating all of the other distance adjustment devices except the distance adjustment device provided on the reference suspension rope in a state where the suspended load is suspended, A suspended load attitude adjustment method.

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