crane equipment

Abstract

To provide a crane device that can prevent erroneous lifting due to malfunctions. [Solution] The crane device 1 includes a hook 3 that is rotatably supported horizontally on a hook block 2 that moves up and down, and a suspension rope such as a wire rope 10 formed by twisting together a plurality of strands 11 to connect the load 100 to the hook 3. The crane device 1 also includes a rotation sensor 22 that detects the rotation state of the hook 3, and a determination circuit that determines an abnormality in the wire rope 10 suspending the load 100 from the rotation state of the hook 3 detected by the rotation sensor 22 when raising the load 100 from the ground.

Description

Technical Field

[0001] The present invention relates to a crane device.

Background Art

[0002] Conventionally, there has been known a crane device that transports a suspended load by connecting between a suspended load such as a mold and a hook using a plurality of wire ropes or suspension ropes such as nylon slings and suspending them in a balanced state (see, for example, Patent Document 1). In such a case, after lowering the suspended load to the target location, the wire ropes hooked to the hook are removed. Then, with the hook in the unloaded state where all the wire ropes have been removed, the hook is raised again to the initial position to end the operation. <00 ,00017> Also, there is known a device that detects whether the upper end of a wire rope is hooked to a hook using a distance measuring sensor provided on the hook (see, for example, Patent Document 2).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in Patent Document 1, after lowering the suspended load, the connection by all the wire ropes is released. For example, if an operator forgets to remove one or several wire ropes from the suspended load, the unloaded state is not achieved. When performing the operation of raising the hook to the initial position in this state, there is a problem that the suspended load is lifted in an unbalanced state.

[0006] Furthermore, in the method described in Patent Document 2, the distance measuring sensor installed on the hook cannot detect whether the lower end of the wire rope has been removed from the suspended load. When transporting multiple molds in succession, for example, it may be necessary to move on to transporting the next suspended load while the wire rope is still attached to the hook.

[0007] In such cases, there is a risk that the suspended load may tilt due to being lifted by one or more wire ropes that were forgotten to be detached from the load, and further improvements are needed. This invention has been made in view of the above circumstances, and aims to provide a crane device that can prevent erroneous lifting in abnormal conditions. [Means for solving the problem]

[0008] To solve the aforementioned problems, the crane device of the present invention is characterized by comprising: a hook supported so as to be rotatable in the horizontal direction on a hook block that moves up and down; a suspension cable connecting a load to the hook; a rotation sensor for detecting the rotation state of the hook; and a determination circuit for determining an abnormality in the suspension cable suspending the load from the rotation state of the hook detected by the rotation sensor when raising the load from a ground-level position. [Effects of the Invention]

[0009] According to the present invention, a crane device is provided that can prevent erroneous lifting in abnormal conditions. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic perspective view showing how a crane device according to the first embodiment successfully lifts a load using four wire ropes. [Figure 2] This is a front view showing the wire rope used in the crane device of the first embodiment. [Figure 3] This is a front view showing the configuration of a crane device according to the first embodiment, illustrating the relationship between the hook and the rotation sensor provided on the hook block. [Figure 4]It is a block diagram for explaining the connection relationship of the control unit in the crane device according to the first embodiment. [Figure 5] It is a timing chart showing the behavior of the hook and the suspended load in the case of four-point suspension in time series. The upper part shows the state of the hoisting operation, the middle part shows the rotation state of the hook, and the lower part shows the timing chart of the load detection state. [Figure 6] It is a timing chart showing the behavior of the hook and the suspended load in the case of single-point suspension in time series. [Figure 7] It is a timing chart showing the behavior of the hook and the suspended load in the case of two-point suspension in time series. [Figure 8] It is a schematic top view showing the hook and the wire rope in the case of two-point suspension, explaining the rotation of the hook before lifting (left) and when being lifted (right). [Figure 9] It is a table diagram explaining the rotation of the hook and the state of the suspended load for each number. [Figure 10] It is a timing chart showing the behavior of the hook and the suspended load in the case of no load in time series. [Figure 11] It is a diagram explaining the correlation from the wire rope specification selected according to the suspended load weight to the setting of the load sensor. [Figure 12] It is a flowchart for explaining the abnormality determination of the first embodiment. [Figure 13] It is a flowchart for explaining the abnormality determination using the load sensor in the second embodiment. [Figure 14] It is a flowchart for explaining the abnormality determination of the third embodiment. [Figure 15] It is a schematic top view showing the hook and the wire rope in the case of three-point suspension in the fourth embodiment, explaining the rotation of the hook when being lifted. [Figure 16] It is a schematic top view showing the hook and the wire rope in the case of two-point suspension, explaining the lifting of the short side of the suspended load. [Figure 17] It is a schematic top view showing the hook and the wire rope in the case of two-point suspension for lifting the suspended load diagonally. [Figure 18]It is a schematic top view showing a hook and a wire rope in the case of single-point suspension of a suspended load. [Figure 19] It is a schematic top view showing a hook and a wire rope in the case of double-point suspension of a suspended load with the long side used for lifting. [Figure 20] It is a graph showing the pulses of a pulse coder that change over time. [Figure 21] It is a graph in which the angular velocity calculated from the number of pulses generated per specified unit time is plotted on the vertical axis and each acceleration is displayed by the slope. [Figure 22] It is a flowchart for explaining the abnormality determination of the fourth embodiment.

Mode for Carrying Out the Invention

[0011] Hereinafter, in the embodiments of the present invention, the description will be made with reference to the drawings as appropriate. The same reference numerals are given to the same components and the overlapping description will be omitted.

[0012] As shown in FIG. 1, in the first embodiment, a crane device 1 such as an overhead crane is provided on the ceiling of a factory or the like. The crane device 1 is mainly used for a transportation operation of lifting a suspended load 100 having a predetermined weight such as a metal mold and moving it horizontally in the factory in the horizontal direction H.

[0013] For this reason, the crane device 1 has a hoist and a hook block 2 that move horizontally along a ceiling rail (not shown). A main wire 5 extending from the hoist is hung on the hook block 2, and a sheave 4 that moves up and down in the vertical direction V while rotating and a hook 3 in the shape of a hook are provided by winding up or feeding out.

[0014] The hook 3 of the first embodiment is configured to connect four wire ropes 10 as suspension ropes to the suspended load 100 and lift it. As shown in Figure 2, the wire rope 10 used as a suspension rope is formed by twisting together multiple strands 11. The wire rope 10 has a main body 12 as the wire body and an upper ring portion 13 formed in an annular shape at the upper end of the main body 12 by a fastener 15. The wire rope 10 also has a lower ring portion 14 formed in an annular shape at the lower end opposite the upper ring portion 13 by a fastener 16.

[0015] The strands 11 are twisted together so that the winding direction of the strands 11 is aligned with either the left or right rotation direction. Therefore, when tension is applied in the vertical direction to the main trunk 12 between the upper ring section 13 and the lower ring section 14, it rotates in the opposite direction to the twist, causing it to untwist. During the untwisting, the main trunk 12 mainly elongates, increasing the overall length of the wire rope 10, while the upper ring section 13 and the lower ring section 14 rotate relative to each other.

[0016] The upper ring portion 13 of each wire rope 10 is attached to the hook 3, and the lower ring portion 14 is attached to the locking claw portions 101 provided at the four corners of the suspended load 100, thereby connecting the hook 3 and the suspended load 100. As a result, when the main wire 5 is wound up by the hoist of the crane device 1, the sheave 4 rotates and vertically raises the hook block 2 along the vertical direction V. The suspended load 100, connected to the hook 3 by the wire rope 10, is lifted from its position on the floor or other molds, etc., and floats as shown in Figure 1, and is moved horizontally H to the desired location.

[0017] As shown in Figure 3, a shaft hole 9 is formed through the hook block 2 in the vertical direction. The shaft portion 8 of the hook 3 is inserted into the shaft hole 9 from below upward. A hook nut 6 is provided on the upper part of the shaft portion 8. The hook nut 6 is secured to the opening periphery of the shaft hole portion 9 of the hook block 2 via a friction-reducing member such as a ball bearing 7 to prevent it from falling out in the vertical direction. As a result, the hook 3 is supported so as to be rotatable horizontally relative to the vertically moving hook block 2.

[0018] The crane device 1 of the first embodiment is equipped with a rotation detection unit 20 on the upper side of the shaft portion 8 of the hook 3 for detecting the rotation state of the hook 3. The rotation detection unit 20 includes a pulley 21 attached to the upper end of the shaft portion 8 of the hook 3, and a rotation sensor 22 consisting of an encoder (also called a pulse encoder) that optically or magnetically detects the rotation of the shaft 23 and converts it into an electrical rotation signal.

[0019] The rotation sensor 22 is fixed to the side of the hook block 2 using a fixing bracket 26. This ensures that the encoder shaft 23 is positioned parallel to the direction of the shaft portion 8 of the hook 3. A driven pulley 24 is fixed to the upper end of the shaft 23 of the rotation sensor 22.

[0020] Between the driven pulley 24 and the pulley 21 fixed to the shaft portion 8 of the hook 3, an annular rotating belt 25 is provided, which, by connection, rotates the driven pulley 24 in synchronization with the pulley 21. Therefore, when the hook 3 rotates, the driven pulley 24 rotates synchronously via the pulley 21 and the rotating belt 25, causing the shaft 23 of the rotation sensor 22 to rotate. Thus, the rotation state of the hook 3 is detected optically or magnetically as the rotation state of the shaft 23 and converted into an electrical rotation signal by the encoder. As a result, the rotation sensor 22 can detect the rotation state of the hook 3.

[0021] As shown in Figure 4, the crane device 1 of the first embodiment is equipped with a control device 30 that controls the hoisting operation of the wire rope 10 by the hoisting machine. A rotation sensor 22 is connected to the control device 30. The rotation signal indicating the rotation state of the hook 3 detected by the rotation sensor 22 is output from the rotation sensor 22 and input to the control device 30.

[0022] Furthermore, a load sensor 32 is connected to the control device 30 to detect the load applied to the main wire 5. The load sensor 32 detects the weight of the hook 3, the total weight of the suspended wire rope 10 and the suspended load 100, and converts it into an electrical load signal. The load signal output from the load sensor 32 is then input to the control device 30. Note that an existing load cell or the like may be used as the load sensor 32.

[0023] Furthermore, the control device 30 is connected to an operating unit 34 equipped with a hoist that the operator uses to perform lifting and lowering operations, and a drive output unit 35 that controls the drive of the hoisting machine to be turned on or off in response to the lifting and lowering operations performed by the operating unit 34. As shown in Figure 4, the control device 30 is equipped with a determination circuit 31. The determination circuit 31 is configured to determine if there is an abnormality in the wire rope 10 suspending the load 100 from the rotation state of the hook 3 detected by the rotation sensor 22 when the suspended load 100 is raised from the ground.

[0024] More specifically, in the control device 30 of the first embodiment, when the operator performs a lifting operation to raise the hook 3 using the hoist of the operating unit 34, the drive output unit 35 controls the drive of the hoisting machine to ON in accordance with the drive output signal output to the hoisting machine and starts winding up the main wire 5. The determination circuit 31 uses the rotation signal input from the rotation sensor 22 and the load signal input from the load sensor 32 to determine whether the crane operation is being performed in a normal state or an abnormal state.

[0025] Furthermore, in the first embodiment, the control device 30 allows the hoisting machine to continue its winding operation when it is in a normal state. In the event of an abnormal state, the drive output unit 35 is configured to turn off the drive of the hoisting machine and stop the winding by the main wire 5. One or more wire ropes 10 are attached to hook 3, and a load 100 is suspended from it.

[0026] In the first embodiment, as shown in Figure 1, four wire ropes 10 are attached to the locking claws 101 at the four corners in order to lift a nearly flat rectangular molding die as the suspended load 100. Since the four wire ropes 10 are of equal length, the suspended load 100 is pulled upward evenly by each wire rope 10. Therefore, even after the suspended load 100 is lifted into the air by the ground break, it can maintain balance and a horizontal position as it is mounted.

[0027] Figure 5 shows the rotation state of hook 3 and the load applied from the suspended load 100 over time in the case of a four-point suspension. The horizontal axis in Figure 5 is the time axis T(s). Furthermore, the upper part of Figure 5 shows the drive output signal output from the drive output unit 35 to the hoisting machine as a result of the lifting and lowering operation of the operating unit 34 shown in Figure 4. Here, it is shown that when the drive output signal for raising the hook 3 is in the ON state, the amplitude of the drive signal is large, and when it is in the OFF state, the amplitude of the drive signal is smallest.

[0028] In the hoisting operation shown in Figure 5, the hoisting button on the hoist of the control unit 34 is pressed down three times, outputting three drive signals A1, A2, and A3. In this way, the hoisting machine of the crane device 1 can perform hoisting by inching operations divided into three stages. During the inching operation, an off state occurs intermittently between on states. In the off state, the main wire 5 is locked by the brake of the reverse rotation prevention mechanism provided on the lifting machine, preventing it from being fed out.

[0029] The middle section of Figure 5 shows the rotation signal output from the rotation sensor 22, and the horizontal rotation state of the hook 3 can be detected from the rotation signal. When detecting the rotation angle of the hook 3 as the rotation state, with the rated performance of the rotation sensor 22 used in the first embodiment, one pulse causes the hook 3 to rotate 7.2 degrees, and two pulses When this occurs, hook 3 rotates by 14.4 degrees. In this way, the rotation sensor 22 can detect the rotation angle of hook 3 according to the number of detected pulses.

[0030] For example, in the middle section of Figure 5, pulses p1 and p2 are both detected as a single pulse. Therefore, it can be seen that hook 3 has rotated by 7.2 degrees in each case. Furthermore, the control device 30 can calculate the rotational speed as the rotational state of the hook 3 from the rotational signal output from the rotation sensor 22.

[0031] In other words, the rotation speed of hook 3 can be obtained from the pulses that occur per unit of time. If the interval between pulses is long, the rotation speed of hook 3 is slow. Conversely, if the interval is short, the rotation speed of hook 3 is faster than when the interval is long. The control device 30 calculates and quantifies the rotation speeds of pulses p1, p2, etc. The quantified data is used for determination by the determination circuit 31.

[0032] Furthermore, two pulses were detected in pulse p3. Therefore, it can be considered that the rotation angle of hook 3 is 14.4 degrees. The rotation sensor 22 of the first embodiment cannot distinguish between forward and reverse rotation. For example, in the hoisting operation shown in Figure 5, two pulses occur in a short period of time at pulse p3. However, since no pulses are detected after pulse p3, it can be inferred that the machine rotated 7.2 degrees in the forward direction and then returned 7.2 degrees in the reverse direction, resulting in a total of 0 degrees.

[0033] In other words, it is highly likely that the hook 3 swayed back once, or that it swayed slightly before stopping. For this reason, an angle threshold, as described later, is set in advance to exclude rotations of small angles, such as back-swaying. Thus, the control device 30 of the crane device 1 can obtain data on the rotation angle and rotation speed of the hook 3 as the rotation state from the pulsed rotation signal detected by the rotation sensor 22. For this reason, the determination circuit 31 can use the rotation signal data input to the control device 30 as the rotation angle and rotation speed of the hook 3.

[0034] As a result, the judgment circuit 31 can determine if there is an abnormality in the number of wire ropes 10 suspending the suspended load 100 when raising the suspended load 100 from the ground. The lower part of Figure 5 shows the state of the load signal detected by the load sensor 32.

[0035] In the reference region H1 shown in Figure 5 before and after lifting, the third drive signal A3 is output at time t1, and along with the inching operation, the detection of the load signal begins, and the load signal increases as time progresses until time t2. That is, it is estimated that tension is applied to the wire rope 10 starting with the third inching operation and gradually increasing over time.

[0036] At time t2, a load of 0.5t is applied to hook 3. At this point, tension is applied to wire rope 10, but the suspended load 100 has not yet been lifted off the ground. The determination circuit 31 of the control device 30 utilizes the load signal detected by the load sensor 32 to determine the timing when tension begins to be applied to the wire rope 10 when the suspended load 100 is raised from the ground, and the timing when the suspended load 100 is lifted off the ground.

[0037] For example, as in the lifting operation shown in Figure 5, the determination circuit 31 of the control device 30 does not determine that there is an abnormality in the wire rope 10 if the rotation angle detected by the rotation sensor 22 is less than a preset angle threshold. In other words, in the case of a flat suspended load 100 as in the first embodiment, by using four wire ropes 10, the suspended load 100 is stabilized in a horizontal position. Since the suspended load 100 does not tilt even when it is suspended in the air, it is lifted in a normal state. For example, when using the four wire ropes 10 shown on the left side of Figure 8, the suspended load 100 is stable in a horizontal position, and the hook 3 hardly rotates because it is pulled from all four sides.

[0038] Furthermore, even if a rebound like pulse p3 occurs due to a shift in the initial position of hook 3, the control device 30 can exclude rotations of small angles by calculation by setting an angle threshold. The determination circuit 31 determines that the system is in a normal state when the rotation sensor 22 detects that the rotation angle of the hook 3 in the main reference region H1 is less than the angle threshold. Note that the main reference region H1 is enclosed in the diagram for the purpose of making the explanation easier to understand, and similarly, the reference regions H2 to H4 described later do not actually exist, and the detection time of the angle signal and load signal is not limited to this region. In the crane device 1 of the first embodiment, the detection of the angle signal and load signal starts at the start of the hoisting operation, which is one of the crane operations.

[0039] When the determination circuit 31 determines that the system is in a normal state, the control device 30 can continue outputting the drive signal from the drive output unit 35 to improve the efficiency of the transport operation. The determination circuit 31 of the first embodiment can determine from the rotation angle detected by the rotation sensor 22 whether the crane device 1 is in a normal state where it is lifting with all four legs suitable for transport operations, or whether it is in an abnormal state where transport operations cannot be continued.

[0040] For example, if one to three wire ropes 10 are attached to their respective locking claws 101, there is a risk that the suspended load 100 will tilt immediately after the ground is opened. In this state, transportation work cannot be carried out. Also, there is a risk that the suspended load 100 may be damaged or come into contact with the surroundings due to the load shifting, so it is necessary to immediately stop the hoisting of the main wire 5 by the hoisting machine. Furthermore, it is preferable to stop the hoisting operation of the hoisting machine at an early stage before the suspended load 100 tilts.

[0041] The judgment circuit 31 determines that if the rotation speed of the hook 3 detected by the rotation sensor 22 exceeds a preset speed threshold, it is an abnormal situation in which the load 100 is being lifted by one to three wire ropes 10. When the judgment circuit 31 determines that an abnormal situation exists, the control device 30 stops the output of the drive signal from the drive output unit 35. This temporarily stops the lifting operation, allowing the operator to inspect the wire ropes 10 for any abnormalities and then restore the operation.

[0042] For example, a load 100 that should normally be suspended using four wire ropes 10 may be suspended using only one wire rope 10 due to forgetting to detach it or other reasons. Figure 6 shows the rotation signal indicating the rotation state of the hook 3 and the load signal indicating the load applied from the load 100, in chronological order along with the timing of the inching operation by the hoisting machine.

[0043] In Figure 6, as shown in the reference region H2, when tension begins to be applied to the wire rope 10 by the inching operation, the rotation angle of the hook 3 increases and the rotation speed increases according to the rotation sensor 22 from the moment the inching operation is turned off, prior to the time t3 when the load sensor 32 begins detecting the load signal.

[0044] Furthermore, even after time t4, when the suspended load 100 was released from the ground and lifted into the air, the rotation sensor 22 continues to detect pulse p10 indicating the rotation of the hook 3. Therefore, it can be inferred that the strands 11 constituting the main trunk 12 are twisting back as the load 100 is being lifted by a single wire rope 10 as shown in Figure 2.

[0045] The force of the single wire rope 10 trying to untwist is transmitted to the hook 3 as a rotational force, causing the hook 3 to rotate horizontally relative to the hook block 2. Therefore, the determination circuit 31 can easily determine that there is an abnormality by detecting, using the rotation sensor 22, that the hook 3 is rotating at or above a predetermined angle threshold or speed threshold. In Figure 6, the rotation state detected by the rotation sensor 22 has a large rotation angle and a high rotation speed, so the determination circuit 31 determines that the load 100 is being lifted by a single wire rope 10.

[0046] In this way, if an abnormal number of wire ropes 10 are used to lift the load 100, the control device 30 can change the drive output signal of the drive output unit 35 to automatically turn off the drive of the hoisting machine. This prevents the hoisting operation from being stopped before the load 100 leaves the ground, thus preventing the load 100 from losing balance and tilting.

[0047] Furthermore, the determination circuit 31 of the first embodiment can determine that the wire rope 10 is in an abnormal state even if the rotation angle detected by the rotation sensor 22 is less than a preset angle threshold, as long as the rotation speed of the hook 3 detected by the rotation sensor 22 is equal to or greater than a preset speed threshold.

[0048] Figure 7 shows the rotation state of the hook 3 and the load applied from the suspended load 100 over time, in the case where the suspended load 100 is lifted using two or three wire ropes 10 due to forgetting to detach them, etc., whereas under normal conditions it is lifted using four wire ropes 10.

[0049] In Figure 7, when tension begins to be applied to the wire rope 10 by the inching operation in the reference region H3, the rotation of the hook 3 is detected by the rotation sensor 22 after time t5, just before time t6 when the load sensor 32 begins detecting a load signal. In this case, the rotation angle of the hook 3 detected by the rotation sensor 22 is less than a preset angle threshold. However, since it rotates to a predetermined angle within a short time between time t5 and time t6, the rotation speed is greater than or equal to a preset speed threshold.

[0050] The determination circuit 31 can determine that there is an abnormality if the rotation speed of the hook 3 detected by the rotation sensor 22 exceeds a preset speed threshold. For example, in Figure 7, there are few pulses p6 and the rotation angle is small. Even in this case, if multiple pulses p6 are detected between time t5 and time t6, and the rotation speed exceeds a preset speed threshold, the rotation angle may not meet the preset angle threshold despite being lifted by two or three wire ropes 10.

[0051] Therefore, the determination circuit 31 may calculate from the number of pulses p6 detected by the rotation sensor 22 between time t5 and time t6, just before the suspended load 100 is released from the ground and lifted into the air, and if the determined rotation speed is high, it may determine that the wire rope 10 is attempting to lift the load with an abnormal number of wire ropes 10, such as two or three (hereinafter also referred to as two, etc.), and automatically turn off the drive of the hoisting machine.

[0052] Here, we will explain using Figure 8 why the case where the wire rope 10 is normal with four strands and the case where it is abnormal with two strands can be distinguished using a preset angle threshold or velocity threshold.

[0053] In the top view shown on the left side of Figure 8, when the load 100 is suspended by four wire ropes 10A to 10D, the hook 3 is pulled almost equally by each wire rope 10A to 10D. Furthermore, when using only one wire rope 10, the forces that would cause twisting and attempt to rotate the load 100 and the hook 3 are counteracted and balanced. As a result, the hook 3 hardly rotates, and the rotation speed does not increase significantly.

[0054] In contrast, if wire ropes 10C and 10D are not hooked onto hook 3, as shown by the dashed lines, and hook 3 is only hooked onto wire ropes 10A and 10B, as shown by the solid lines, then hook 3 will be pulled toward one side of the suspended load 100 (towards the top of the paper). The upper rings 13A and 13B of wire ropes 10A and 10B are attached to hook 3 at different positions side by side. Also, since the lengths of wire ropes 10A and 10B are approximately the same, they rotate 90 degrees counterclockwise and stop, as shown in the top view on the right side of Figure 8.

[0055] Therefore, when there are two wire ropes 10, for example, the determination circuit 31 can easily distinguish between the case with four wire ropes and the case with four wire ropes by determining whether the ropes are before or after a predetermined angle threshold. In the crane device 1 of the first embodiment, the angle threshold is set to a range of approximately 30 degrees to approximately 70 degrees, preferably approximately 50 degrees.

[0056] Figure 9 is a table summarizing the rotational speed of the hook 3 generated by the suspension of the load 100 when the number of wire ropes 10 is one to four, and when there is no load (0). First, let's explain how to set the angle threshold. When lifting load 100 with a single hook, hook 3 rotates several to several dozen times, so setting the angle threshold to approximately 50 degrees will almost certainly exceed the threshold.

[0057] Furthermore, as explained in Figure 8, when there are two wire ropes 10 used for suspension, the rotation is approximately 90 degrees. Similarly, when there are three wire ropes, the rotation is approximately 60 degrees or more, close to 90 degrees. When four wires are used for suspension, there is almost no rotation. Therefore, in the first embodiment, the angle threshold is set to 50 degrees. As a result, when lifting the load 100 with two or three wire ropes 10, the angle threshold of 50 degrees is often exceeded, but when lifting with four ropes, the angle threshold of 50 degrees is not exceeded.

[0058] Furthermore, in the case of an empty load, the angle threshold is usually not exceeded by 50 degrees, but as shown in Figure 10, in the reference region H4, the rotation sensor 22 may detect a pulse p10 indicating that the hook 3 has rotated by more than 50 degrees. Even if such an angle of rotation of the hook 3 exceeding the angle threshold is detected, if the load sensor 32 does not detect a load applied to the hook 3 after the time t10 when the suspension begins, it may be determined that there is no load. For this reason, the crane device 1 of the first embodiment can easily determine that there is no load using the determination circuit 31, regardless of the size of the rotation angle or rotation speed.

[0059] Next, we will explain the setting of the speed threshold, which is done in advance in the crane device 1. In Figure 9, when there is one wire rope 10, the hook 3 rotates at a rotational speed of approximately 100 degrees / second or more. When there are two wire ropes, the hook 3 rotates at a rotational speed of approximately 50-60 degrees / second or more.

[0060] Therefore, in the first embodiment, the speed threshold is set to approximately 40 degrees / second or higher in advance. This makes it possible to determine that the case in which the load 100 is suspended by four wire ropes 10 with hooks 3 rotating at a rotation speed of approximately 15 degrees / second is a normal state, unlike the case in which it is suspended by one to three ropes.

[0061] As shown in Figure 11, in the threshold setting process of the first embodiment, the weight of the suspended load 100 is set in step S1. The weight of the suspended load 100 is the weight of a normal transported object. Furthermore, in step S2, a wire specification capable of withstanding the weight of the suspended load 100 is selected. The specifications of the wire rope 10 include the load capacity set to prevent plastic deformation and the number of strands 11. In step S3, the load threshold of the load detected by the load sensor 32 is set. In the crane device 1 of the first embodiment, the load threshold is set to 2 percent of the wire rating.

[0062] The basis for setting the load threshold at 2 percent is that it is determined based on the lifting speed of the crane device 1, taking into account the time lag from the stop control by the control device 30 until the lifting operation comes to a complete halt. Thus, it can be seen that there is a correlation between the specifications of the wire rope 10 selected to match the lifting load and the settings of the load sensor. For this reason, the crane device 1 can pre-set the load threshold for the load signal detected by the load sensor 32 based on the weight of the lifted load 100 and the specifications of the wire rope 10 set in steps S1 to S2.

[0063] In Figure 9, the "Load Detection" column is set to "yes" if the load signal value detected by the load sensor 32 exceeds a preset load threshold, and to "no" if it does not exceed the load threshold. As a result, in the crane device 1 of the first embodiment, except when empty, the load applied to the load sensor 32 in all suspended states using the number of wire ropes 10 exceeds a preset load threshold.

[0064] Thus, it is preferable to set the load threshold to be greater than the tension at which the wire rope 10 unravels. This makes it possible to detect the rotation of the hook 3 due to the unravelling of the wire rope 10 even before load detection occurs during the lifting operation.

[0065] As shown in Figure 12, in the abnormality detection process performed by the control device 30 of the crane device 1 of the first embodiment, first, in step S10, the crane operation is started. In step S11, the operator uses the hoist on the control unit 34 to perform the crane hoisting operation. When the push-button switch for winding up the main wire 5 (see Figure 1) on the hoist is turned ON (Yes in step S11), the hoisting machine raises the hook 3 in response to the drive signal output from the drive output unit 35 and proceeds to step S12.

[0066] Furthermore, if no crane hoisting operation is performed (No in step S11), the process proceeds to step S15, and the determination circuit 31 of the control device 30 determines that it is normal. Since the crane operation by the crane device 1 is determined to be normal in step S15, it becomes possible to move the hoisting machine horizontally in direction H along the ceiling rail, and the suspended load 100 can be moved to the desired position.

[0067] In step S12, the determination circuit 31 determines whether the rotation angle of the hook 3 detected by the rotation sensor 22 is greater than or equal to a preset angle threshold. If the rotation angle of the hook 3 is less than the preset angle threshold (No in step S12), the process proceeds to step S15, where the determination circuit 31 of the control device 30 determines that it is normal.

[0068] Therefore, in the case of a four-point suspension as shown in Figure 5, step S15 indicates that the number of wire ropes 10 is normal and that the operation is being performed correctly. Thus, there is no need to interrupt the transport operation. On the other hand, if the rotation angle of hook 3 is greater than or equal to a preset angle threshold (Yes in step S12), the process proceeds to the next step S13.

[0069] In step S13, the determination circuit 31 determines whether the rotation speed of the hook 3 is equal to or greater than the speed threshold. If the rotation speed of hook 3 is greater than or equal to the speed threshold (Yes in step S13), proceed to step S14. For example, in the first embodiment, the speed threshold is set to approximately 40 degrees / second in advance.

[0070] Therefore, as shown in Figure 9, if there is only one wire rope 10, or if there are two or three abnormal wire ropes 10, the rotation speed of the hook 3 will be approximately 50 degrees / second or more, which will be detected as exceeding the speed threshold, and the process will proceed to step S14. Furthermore, if the rotation speed of hook 3 is less than the speed threshold, i.e., not greater than or equal to the speed threshold (No in step S13), the process proceeds to step S15 and is determined to be normal.

[0071] In step S14, the determination circuit 31 determines that the hook 3 is rotating using only one wire rope 10. In addition to this determination, if there are two or three abnormal wire ropes 10 other than four, the determination circuit 31 of the crane device 1 of the first embodiment determines that there is an abnormality. For this reason, the crane device 1 of the first embodiment can stop the crane hoisting operation before the load 100 is lifted.

[0072] Figure 13 illustrates the abnormality detection process performed by the control device 30 of the crane device 1 in the second embodiment. In the second embodiment, the load signal detected by the existing load sensor 32 in the crane device 1 of the first embodiment is used for the determination by the determination circuit 31.

[0073] First, in Figure 13, once the crane operation begins in step S20, the operator performs the crane hoisting operation using the hoist of the control unit 34 in step S21. If the winding switch is turned ON (Yes in step S21), the process proceeds to step S22. If it is not turned ON (No in step S21), the process proceeds to step S26 and is judged to be normal.

[0074] In step S22, the load signal detected by the load sensor 32 is used by the determination circuit 31 to determine whether the load on the hook 3 is equal to or greater than a preset load threshold. In the determination circuit 31, if the load is greater than or equal to the load threshold (Yes in step S22), the process proceeds to step S23. If the load is less than the load threshold, it is not greater than or equal to the load threshold (No in step S22), so the process proceeds to step S26 and is determined to be normal.

[0075] As a result, in the case of an empty load as shown in Figure 10, it is determined in step S26 that normal work is being performed, and there is no need to interrupt the work. In step S23, the determination circuit 31 determines whether the rotation angle of the hook 3 detected by the rotation sensor 22 is greater than or equal to a preset angle threshold. If the rotation angle of the hook 3 is greater than or equal to the preset angle threshold (Yes in step S23), the process proceeds to the next step S24. If the rotation angle is less than the angle threshold (No in step S23), the process proceeds to step S26.

[0076] In step S26, it is determined that the work is being performed normally with four wire ropes, which is the normal number of wire ropes 10, and therefore there is no need to interrupt the work. On the other hand, when the process proceeds to step S24, the determination circuit 31 determines that there are one to three abnormal wire ropes 10. In step S24, the determination circuit 31 determines whether the rotation speed of the hook 3 is above the speed threshold.

[0077] If the rotation speed of hook 3 is greater than or equal to the speed threshold (Yes in step S24), proceed to step S25. If the rotation speed of hook 3 is less than or equal to the speed threshold (No in step S24), proceed to step S26 and it is determined to be normal. In step S25, similar to the first embodiment, the determination circuit 31 of the control device 30 determines that the rotation state in which the hook 3 is rotating with one wire rope 10 is abnormal, and that there is a possibility of an abnormal number of wire ropes 10, such as two or three, in addition to the empty load. As a result, in the crane device 1 of the second embodiment, the crane hoisting operation can be stopped even if the load sensor 32 has not detected a load exceeding the load threshold, before the suspended load 100 loses balance and tilts.

[0078] Other configurations and effects are the same as in the first embodiment, so their explanation will be omitted. Figure 14 illustrates the abnormality detection process performed by the control device 30 of the crane device 1 in the third embodiment. In the third embodiment, we will explain the case where, in step S12 of the first embodiment (see Figure 12) and step S23 of the second embodiment (see Figure 13), the rotation angle detected by the rotation sensor 22 is less than the angle threshold, and the process proceeds to steps S30 to S32 shown in Figure 14. Other configurations and effects are the same as in the first and second embodiments, so their explanation will be omitted.

[0079] In the crane device 1 of the third embodiment, the process proceeds to step S30 shown in Figure 14. Then, the determination circuit 31 determines again whether the rotation speed of hook 3 is above the speed threshold. If the rotation speed of hook 3 is greater than or equal to the speed threshold (Yes in step S30), proceed to step S31. If the rotation speed of hook 3 is less than the speed threshold, i.e., not greater than or equal to the speed threshold (No in step S30), proceed to step S32 and it is determined to be normal.

[0080] In the crane device 1 of the third embodiment, in step S30, the determination circuit 31 determines in step S31 that there is an abnormality if the rotational angle detected by the rotation sensor 22 is less than a preset angle threshold, but the rotational speed of the hook 3 detected by the rotation sensor 22 is greater than or equal to a preset speed threshold.

[0081] For example, in a normal state as shown in Figure 7, a load 100 is lifted using four wire ropes 10, but in some cases, due to forgetting to detach them, it may be lifted using only two or three wire ropes 10. In such cases, the initial position of hook 3 may be less than approximately 50 degrees, and a misalignment may have occurred, which should be determined to be abnormal.

[0082] For example, when two wire ropes 10 are attached diagonally to a suspended load 100, the rotation angle may be as small as about 20 degrees, and may not exceed the angle threshold set at 50 degrees. Therefore, in addition to the effects and advantages of the first and second embodiments, the crane device 1 of the third embodiment can obtain the following further effects and advantages.

[0083] In other words, in Figure 7, even if the rotation angle of the hook 3 detected by the rotation sensor 22 is less than a preset angle threshold, it is detected that it rotates to a predetermined angle within a short time between time t5 and time t6, and that the rotation speed is equal to or greater than a preset speed threshold. Furthermore, it can be determined that the wire ropes 10 are not suspended in a normal state with all four ropes, but rather with two or three ropes, and that an attempt is being made to lift in an abnormal state. As a result, the crane device 1 of the third embodiment can further improve the accuracy of the determination. Other configurations and effects are the same as those of the first and second embodiments, and therefore will not be described.

[0084] Figure 22 illustrates the abnormality detection process performed by the control device 30 in the crane device 1 of the fourth embodiment. In this fourth embodiment, the differences from the crane device 1 of the first to third embodiments will be explained in detail, and other configurations and effects will be omitted as they are the same as those of the first to third embodiments.

[0085] In the crane device 1 of the fourth embodiment, instead of the wire rope 10 used as the suspension cable in the crane device 1 of the first to third embodiments, a strip-shaped nylon sling 40 is used as the suspension cable. Furthermore, because the size and weight specifications of the suspended load 100 are different, the angle threshold is set to approximately 5 degrees, which is different from the crane device 1 of the first to third embodiments.

[0086] The determination circuit 31 (see Figure 4) determines that the number of nylon slings 40 suspending the load 100 is abnormal if the rotation angle of the hook 3 detected by the rotation sensor 22 is greater than or equal to a preset angle threshold. In other words, if the suspended load 100 is connected to the hook 3 with fewer nylon slings 40 than the specified number, the balance will be disrupted and the hook 3 will rotate.

[0087] For example, if, despite the default number of nylon slings 40 being four, one is accidentally detached and the load is suspended with only three slings as shown in Figure 15, the balance will be disrupted and the hook 3 will rotate relative to the hook block 2 (see Figure 2). It will then stop at a position where the balance of the three slings is maintained, rotated by approximately 10 degrees.

[0088] In the crane device 1 of the fourth embodiment, the angle threshold is set to approximately 5 degrees. Therefore, when the rotation sensor 22 detects that the hook 3 has rotated to approximately 5 degrees or more, which is the preset angle threshold, the determination circuit 31 can easily determine that there is an abnormality in the number of suspension ropes suspending the load 100, which is not the predetermined four.

[0089] Furthermore, for example, in the case of a two-point lifting method where the load 100 is lifted by attaching it to its short side as shown in Figure 16, the balance is disrupted and the hook 3 rotates relative to the hook block 2. It then stops at a position where the balance is maintained, rotated approximately 90 degrees. In the crane device 1 of the fourth embodiment, the angle threshold is set to approximately 5 degrees. Therefore, when the rotation sensor 22 detects that the hook 3 has rotated to approximately 5 degrees or more, which is the preset angle threshold, the determination circuit 31 can easily determine that the number of suspension ropes supporting the load is abnormal.

[0090] Furthermore, for example, in the case of a two-point lift, where the load 100 is lifted by attaching the hooks diagonally to each other as shown in Figure 17, the balance is disrupted and the hooks 3 rotate relative to the hook block 2. Then, it stops at a position rotated approximately 30 degrees where the balance is maintained. In the crane device 1 of the fourth embodiment, the angle threshold is set to approximately 5 degrees. Therefore, when the rotation sensor 22 detects that the hook 3 has rotated to approximately 5 degrees or more, which is the preset angle threshold, the determination circuit 31 can easily determine that the number of suspension ropes supporting the load 100 is abnormal.

[0091] Furthermore, for example, in the case of a single-point suspension where the load 100 is attached to one point and lifted, as shown in Figure 18, the balance is disrupted and the hook 3 rotates relative to the hook block 2. It then stops at a position rotated approximately 30 degrees where balance is maintained. In the crane device 1 of the fourth embodiment, the angle threshold is set to approximately 5 degrees. Therefore, when the rotation sensor 22 detects that the hook 3 has rotated to approximately 5 degrees or more, which is the preset angle threshold, the determination circuit 31 can easily determine that the number of suspension ropes supporting the load 100 is abnormal.

[0092] For example, in the case of a two-point lifting method, where the load 100 is lifted by attaching it to its long side as shown in Figure 19, the balance is disrupted and the hook 3 moves parallel to the long side. The hook 3 then stops at a position where balance is maintained. In this case, hook 3 may not rotate beyond a preset angle threshold of approximately 5 degrees. In this state, the judgment circuit 31 cannot determine whether the number of suspension ropes is abnormal (two) or whether it is the default four.

[0093] However, the determination circuit 31 of the crane device 1 in the fourth embodiment further includes a function that determines that the number of suspension ropes 40 suspending the load 100 is not the predetermined four, even if the rotation angle detected by the rotation sensor is less than a preset angle threshold, in this case less than 5 degrees, if the rotational angular acceleration of the hook 3 is greater than or equal to a preset angular acceleration threshold.

[0094] In this case, when hook 3 moves in parallel along the longer side, hook 3 rotates in small increments clockwise and counterclockwise. The judgment circuit 31 is configured to use a preset angular acceleration threshold to determine whether the rotation angle of hook 3 is normal or abnormal, even if the rotation angle of hook 3, which rotates to maintain balance, is less than 5 degrees. For this reason, if the angular acceleration caused by the small rotations and swings of the moving hook 3 exceeds the angular acceleration threshold, the judgment circuit 31 can easily determine that the number of suspension ropes supporting the load 100 is abnormal.

[0095] The pulse resolution of the rotation sensor 22 in the fourth embodiment is 512 P / rev (512 pulses per revolution), which is approximately 0.7 degrees / pulse. If the number of pulses generated per unit time T(s) shown on the horizontal axis of Figure 20 is α pulses, β pulses, and γ pulses, then the angular velocities for adjacent specified unit time periods are 0.7 degrees × α(ω) / T(hour), 0.7 degrees × β(ω) / T(hour), and 0.7 degrees × γ(ω) / T(hour).

[0096] Here, as shown in Figure 21, we plot time (t) on the horizontal axis and angular velocity on the vertical axis. If (ω-Ψ) is the difference in the number of pulses generated during an arbitrarily set time (T1 to T2), then the angular acceleration is (ω-Ψ / T 2 ) are 0.7 × (α-0) / T respectively. 2 , 0.7×(β-α) / T 2 , 0.7 × γ / T 2 This is represented by the slope of the graph (the difference in rotation angle between adjacent time periods). In the fourth embodiment, the angular acceleration is (ω-Ψ / T 2 A predetermined threshold is set in advance.

[0097] Thus, the difference in the number of pulses generated per specified unit time ω between adjacent pulses indicates the angular acceleration. Therefore, the determination by the determination circuit 31 can be performed quickly and easily by setting a predetermined threshold as an allowable upper limit in advance, and determining whether the detected difference in the number of pulses generated ω exceeds this threshold.

[0098] Figure 22 illustrates the abnormality detection process performed by the control device 30 of the fourth embodiment. First, in step S40, the crane operation is started. In step S41, the operator uses the hoist on the control unit 34 to perform the crane hoisting operation. When the push-button switch on the hoist that winds up the main wire 5 (see Figure 1) is turned ON (Yes in step S41), the hoisting machine raises the hook 3 in response to the drive signal output from the drive output unit 35 (see Figure 4) and proceeds to step S42.

[0099] Furthermore, if no crane hoisting operation is performed (No in step S41), the process proceeds to step S45, and the determination circuit 31 of the control device 30 determines that the operation is normal. In step S42, the determination circuit 31 determines whether the rotation angle of the hook 3 detected by the rotation sensor 22 is greater than or equal to a preset angle threshold. If the rotation angle of the hook 3 is less than the preset angle threshold (No in step S42), the process proceeds to step S43.

[0100] Furthermore, if the rotation angle of hook 3 is greater than or equal to a preset angle threshold (Yes in step S42), the process proceeds to step S44 and is determined to be abnormal. For example, if you try to suspend the object with a single nylon sling 40, as shown in Figure 15 with three slings, Figures 16 and 17 with two slings, or Figure 18, the hook 3 will rotate by more than 5 degrees relative to the hook block 2 (see Figure 2). As a result, the process proceeds to step S44, where the determination circuit 31 determines that there is an abnormality and can stop the hoisting operation, similar to the first embodiment.

[0101] In step S43, the determination circuit 31 calculates the rotational angular acceleration of the hook 3 from the number of pulses ω detected by the rotation sensor 22 and determines whether it is normal or abnormal. That is, if the calculated hook angular acceleration is greater than a preset threshold for angular acceleration (Yes in step S43), the process proceeds to step S44 and is determined to be abnormal.

[0102] For example, as shown in Figure 19, if the hook 3 moves parallel to the longer side, the hook 3 will not rotate by more than 5 degrees. The determination circuit 31 determines that the number of suspended nylon slings 40 is abnormal when it detects from the small rotations occurring in the hook 3 that the angular acceleration has exceeded a preset angular acceleration threshold. The determination circuit 31 can then stop the hoisting operation based on the abnormality detection.

[0103] Furthermore, if the calculated Hooke angular acceleration is less than a preset threshold for angular acceleration (No in step S43), the process proceeds to step S45 and is determined to be normal. Thus, in the fourth embodiment, in addition to the effects and advantages of the first to third embodiments, as shown in Figure 19, if the hook 3 moves parallel to the long side, such as in the case of a double suspension where the wire rope 10 is attached to the long side of the suspended load 100, it is possible to determine that this is an abnormality by comparing the detected angular acceleration of the hook 3 with a preset threshold. Therefore, it becomes possible to stop the crane hoisting operation and prevent the suspended load 100 from being lifted in an inclined state.

[0104] As described above, the crane device 1 of the present invention includes a hook 3 that is rotatably supported horizontally on a lifting hook block 2, a wire rope 10 or nylon sling 40 formed by twisting together a plurality of strands 11 to connect the suspended load 100 to the hook 3, a rotation sensor 22 for detecting the rotation state of the hook 3, and a determination circuit 31 that determines an abnormality in the wire rope 10 or nylon sling 40 suspending the suspended load 100 from the rotation state of the hook 3 detected by the rotation sensor 22 when raising the suspended load 100 from the ground.

[0105] This makes it possible to provide a crane device 1 that can prevent erroneous lifting due to abnormalities in the wire rope 10 or nylon sling 40. In other words, when the suspended load 100 is raised from a grounded position, tension is applied to the wire rope 10, which is the suspension cable, causing the wire rope 10 to spring back.

[0106] For example, if the load 100 is properly suspended by a predetermined number of wire ropes 10, the forces trying to unwind will act in opposite directions to cancel each other out, resulting in equilibrium and stopping the rotation of the hook 3. Furthermore, if there is a problem with the wire rope 10, the balance of the unwinding force will be disrupted, causing the hook 3 to rotate.

[0107] Furthermore, even when nylon slings 40 or similar are used as suspension ropes, rotation can occur due to imbalances. Therefore, by detecting the rotation state of the hook 3 with the rotation sensor 22, the determination circuit 31 can determine whether or not there is an abnormality in the number of nylon slings 40 based on the rotation state of the hook 3.

[0108] When the judgment circuit 31 determines that there is an abnormality, the crane device 1 can stop the lifting of the hook block 2, thereby preventing erroneous lifting due to forgetting to remove the lifting rope such as the nylon sling 40. The determination circuit 31 determines that the number of wire ropes 10 suspending the load 100 is abnormal if the rotation speed of the hook 3 detected by the rotation sensor 22 exceeds a preset speed threshold.

[0109] Furthermore, the determination circuit 31 does not determine that there is an abnormality in the suspension cable if the rotation angle detected by the rotation sensor 22 is less than a preset angle threshold. In other words, the determination circuit 31 determines that it is normal if the rotation angle detected by the rotation sensor 22 is less than a preset angle threshold.

[0110] This allows for the exclusion of cases where stable lifting is possible with a predetermined number of lifting points, such as two to four, from the detection of abnormalities. Therefore, the transport operation can be continued, improving work efficiency. Furthermore, the device is equipped with a load sensor 32 that detects the load applied to the hook 3. The determination circuit 31 does not determine that there is an abnormality in the suspension cable if the load detected by the load sensor 32 is less than a preset load threshold.

[0111] This allows the case of an empty load to be excluded from the abnormality detection. In other words, no problem occurs when the load is empty. Therefore, the hook can be safely raised and moved continuously to the initial position or the preparation position for the next transport operation. Consequently, work efficiency can be improved.

[0112] Furthermore, for example, after lowering the suspended load 100 to the desired location, the wire rope 10 attached to the hook 3 may be forgotten. In this case, when the hook 3 is raised to return it to its initial position, the load sensor 32 detects a load exceeding a preset load threshold. As a result, the judgment circuit 31 can determine that the number of wire ropes 10 is abnormal when the load sensor 32 detects a load exceeding a preset load threshold. Therefore, the lifting of the load can be reliably prevented by stopping the rise of the hook 3 using a simple mechanism that utilizes an existing load sensor 32 in the crane device 1.

[0113] Furthermore, the determination circuit 31 can determine that there is an abnormality even if the rotation angle detected by the rotation sensor 22 is less than a preset angle threshold, as long as the rotation speed of the hook 3 detected by the rotation sensor 22 is equal to or greater than a preset speed threshold. For example, in the case shown in Figure 7, even if the rotation angle of the hook 3 detected by the rotation sensor 22 is less than a preset angle threshold, if the rotation speed between time t5 and time t6 exceeds a preset speed threshold, it can be determined that there is an abnormality.

[0114] This provides a crane device 1 that can more accurately distinguish between a normal state with four wire ropes and an abnormal state where it is suspended by two or three wire ropes 10, by employing a simple configuration that relies solely on the detection of rotational state by a rotation sensor 22. Thus, the crane device 1 of the present invention can improve the accuracy of abnormality detection and prevent erroneous lifting due to abnormalities in the wire rope 10.

[0115] Furthermore, the judgment circuit determines that the number of suspension ropes supporting the load is abnormal if the rotation angle detected by the rotation sensor is greater than or equal to a preset angle threshold. As a result, if the suspended load 100 is connected to the hook 3 with fewer nylon slings 40 than the specified number, the hook 3 will rotate in an attempt to maintain balance. For example, if the specified number is four, but the load is suspended with one to three slings, the balance will be disrupted, causing the hook 3 to rotate relative to the hook block 2 and stop at a position where balance is maintained.

[0116] Therefore, the determination circuit 31 can easily determine that the number of suspension ropes supporting the load is abnormal by detecting with the rotation sensor 22 that the hook 3 has rotated to an angle threshold greater than or equal to a preset value. Furthermore, the judgment circuit determines that the number of suspension cables supporting the load is abnormal, even if the rotation angle detected by the rotation sensor is less than a preset angle threshold, if the rotational angular acceleration is greater than or equal to a preset angular acceleration threshold.

[0117] As a result, even if the rotation angle of hook 3, which rotates to maintain balance, is less than a preset angular threshold, if the rotational angular acceleration of hook 3 exceeds a preset angular acceleration threshold, it can be determined that the number of suspension ropes supporting the load is abnormal.

[0118] The present invention is not limited to the embodiments described above, and various modifications are possible. The embodiments described above are illustrative examples provided to facilitate understanding of the present invention, and are not necessarily limited to those comprising all the configurations described. Furthermore, it is possible to replace parts of the configuration of one embodiment with those of another embodiment, and it is also possible to add configurations from other embodiments to the configuration of one embodiment. In addition, it is possible to delete parts of the configuration of each embodiment, or to add or replace other configurations. Possible modifications to the above embodiments are as follows, for example.

[0119] Thus, the crane device 1 of the present invention can improve the accuracy of abnormality detection and prevent erroneous lifting due to abnormalities in the wire rope 10. In other words, in the first embodiment, as shown in Figure 1, four wire ropes 10 are attached to the locking claws 101 at the four corners in order to lift a rectangular parallelepiped molding die that is nearly flat as the suspended load 100. However, the present invention is not particularly limited to this. For example, the suspended load may be of other shapes such as a cube or a pyramidal shape, and the number of wire ropes 10 can also be two or more in a normal state, depending on the suspended load. The shape, material and weight of the suspended load, as well as the length and specifications of the wire ropes 10, are not particularly limited.

[0120] Furthermore, in the crane device 1 of the first embodiment, the angle threshold is set between approximately 30 degrees and approximately 70 degrees, preferably approximately 50 degrees. In the fourth embodiment, the angle threshold is set to approximately 5 degrees. However, the present invention is not particularly limited thereto. For example, if the suspended load has a different shape, such as a cube or a pyramidal shape, or depending on the characteristics and number of wire ropes 10, other thresholds may be set, and the angle threshold is not particularly limited.

[0121] Furthermore, in the first embodiment, the speed threshold is set in advance to approximately 40 degrees / second or more. However, the present invention is not particularly limited thereto. For example, if the suspended load is of a different shape, such as a cube or a pyramidal shape, or depending on the characteristics and number of wire ropes 10, other thresholds may be set, and the speed threshold is not particularly limited.

[0122] Furthermore, in the first embodiment, a wire rope 10 was used as the suspension rope and the invention has been described accordingly. However, the present invention is not limited to this. For example, a nylon sling or the like may be used as the suspension rope. When using a nylon sling, rotation can occur due to an imbalance in the wire rope 10, even without the untwisting of a single wire rope 10. In this way, if the load 100 is connected to the hook 3, the material of the suspension rope is not particularly limited. [Explanation of Symbols]

[0123] 1. Crane equipment 2 Hook Blocks 3 hooks 10. Wire rope (suspension rope) 40 Nylon Slings (Suspension Rope) 11 strands 22 Rotation Sensor 31 Judgment circuit 100 Suspended load

Claims

1. A hook is supported on a lifting hook block so as to be rotatable in the horizontal direction, A suspension rope for connecting a suspended load to the aforementioned hook, A rotation sensor for detecting the rotation state of the hook, When raising the aforementioned suspended load from a grounded position, a determination circuit determines an abnormality in the suspension cable suspending the load based on the rotation state of the hook detected by the rotation sensor, A crane device characterized by being equipped with the following features.

2. The crane device according to claim 1, characterized in that the determination circuit determines that the number of suspension ropes suspending the load is abnormal when the rotation speed of the hook detected by the rotation sensor exceeds a preset speed threshold.

3. The crane device according to claim 1 or 2, characterized in that the determination circuit does not determine an abnormality in the suspension cable if the rotation angle detected by the rotation sensor is less than a preset angle threshold.

4. The hook is equipped with a load sensor that detects the load applied to it, The crane device according to claim 1 or 2, characterized in that the determination circuit does not determine an abnormality in the suspension cable if the load detected by the load sensor is less than a preset load threshold.

5. The crane device according to claim 1 or 2, characterized in that the determination circuit determines that an abnormality exists if the rotation speed of the hook detected by the rotation sensor is equal to or greater than a preset speed threshold, even if the rotation angle detected by the rotation sensor is less than a preset angle threshold.

6. The crane device according to claim 1, characterized in that the determination circuit determines that the number of suspension ropes suspending the load is abnormal when the rotation angle detected by the rotation sensor is greater than or equal to a preset angle threshold.

7. The crane device according to claim 6, characterized in that the determination circuit determines that the number of suspension ropes suspending the load is abnormal if the rotation angle detected by the rotation sensor is less than a preset angle threshold, but the rotational angular acceleration of the hook detected by the rotation sensor is equal to or greater than a preset angular acceleration threshold.

Images