Bucket control device for construction machinery

Abstract

To provide a control device for a construction machine that enables a closing and raising action to be performed by a simple operation and also inhibits a bucket device from opening during the closing and raising action.SOLUTION: When a control mode is set to a synchronization control mode, a specific winding operation is performed, and a bucket device 10 is in a closed state, a drum action control unit 73 of a controller 70 sets a feed-out amount relative difference target value ΔLr based on a set value related to a preset support side loosening amount to avoid the opening of a pair of buckets 13, 13, calculates a feed-out amount relative difference ΔL which is a difference between an opening / closing side feed-out amount and a support side feed-out amount, calculates a deviation H between the feed-out amount relative difference target value ΔLr and the feed-out amount relative difference ΔL, and controls actions of a support drum DR2 and an opening / closing drum DR1 by outputting a command signal such that the deviation H approaches zero, thereby raising the bucket device 10 while maintaining the closed state of the bucket device 10.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present disclosure relates to a bucket control device for opening, closing, raising and lowering a bucket device in a construction machine such as a crane. [Background technology]

[0002] Among conventional construction machines, there is known one that is equipped with a first winch drum that pays out and reels in a first winch rope and a second winch drum that pays out and reels in a second winch rope, and that performs the operations of raising and lowering a load to which the ends of the first and second winch ropes are connected (for example, Patent Document 1).

[0003] Also, among construction machines, there is known one equipped with a bucket device that can be opened, closed, and raised and lowered, such as a clamshell bucket. The ends of first and second winch ropes are connected to this bucket device, and it opens, closes, and rises and falls in response to the winch ropes being let out and reeled in by the first and second winch drums. Therefore, such construction machines are equipped with a first winch operation lever that is operated to operate the first winch drum, and a second winch operation lever that is operated to operate the second winch drum. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-24834 Summary of the Invention [Problem to be solved by the invention]

[0005] For example, to cause a construction machinery operator to perform a "closing-up" operation, which involves raising the bucket assembly while maintaining the bucket assembly closed, the operator must simultaneously operate the first winch operating lever and the second winch operating lever. Performing these two operations simultaneously is time-consuming for unskilled operators who are not skilled in operating construction machinery, and is tiring even for skilled operators. Specifically, to cause the bucket assembly to perform the above-described closing-up operation, it is necessary to adjust the balance between the amount of operation of the first winch operating lever and the amount of operation of the second winch lever so that the bucket assembly does not open during the operation, which makes it difficult to improve workability. The control device in Patent Document 1 does not take into consideration the above-described problems related to the closing-up operation. [Means for solving the problem]

[0006] The present disclosure has an object to solve the above-mentioned problems. That is, the present disclosure has an object to provide a bucket control device for a construction machine that enables an operator to perform a closing operation of the bucket device with a simple operation and that can prevent the bucket device from opening during the closing operation.

[0007] What is provided is a bucket control device mounted on a construction machine that includes a bucket device including a main body and a pair of buckets attached to the main body in an openable and closable manner, a support drum that is a winch drum that is connected to the main body and that reels out and takes up a support rope that supports the main body, and an opening and closing drum that is a winch drum that reels out and takes up an opening and closing rope for opening and closing the pair of buckets, the bucket control device comprising: a support-side winch operation device that is given a support-side winding operation that is an operation for rotating the support drum to reel in the support rope, and a support-side payout operation that is an operation for rotating the support drum to reel out the support rope; an opening and closing-side winch operation device that is given an opening and closing-side winding operation that is an operation for rotating the opening and closing drum to reel in the opening and closing rope, a support-side detector for detecting a support-side payout amount that is the payout amount of the support rope, and an opening and closing-side detector for detecting an opening and closing-side payout amount that is the payout amount of the opening and closing rope. a control mode setting unit capable of setting a control mode to a synchronized control mode in which the winding of the support rope and the winding of the opening and closing rope can be performed based on a specific winding operation which is either the support-side winding operation or the opening and closing-side winding operation; and a controller, wherein the controller includes an open / closed state determination unit that determines whether the pair of buckets are in a closed state, and a controller that determines whether the control mode is set to the synchronized control mode, the specific winding operation is performed, and the bucket device is in the closed state. when it is determined that the above condition is met, a target value for the relative difference in payout amount, which is a target value for the difference between the opening / closing side payout amount and the support side payout amount, is set based on a set value for the support side slack amount, which is a set value set to prevent the pair of buckets from opening, and which is the slack amount of the support rope, and a payout relative difference, which is the difference between the opening / closing side payout amount and the support side payout amount, is calculated, a deviation between the target value for the relative difference in payout amount and the payout relative difference is calculated, and a command signal is output such that the deviation approaches zero, thereby controlling the operation of the support drum and the opening / closing drum,and a drum operation control unit that raises the bucket device while maintaining the closed state of the bucket device.

[0008] With this bucket control device, the operator can perform the closing operation by performing a specific reeling operation that is either the support-side reeling operation or the opening / closing-side reeling operation without performing both operations. Moreover, feedback control is performed so that the deviation between the target value for the relative difference in the payout amount, which is set based on the set value for the support-side slack, and the actual relative difference in the payout amount approaches zero, so the operator can cause the bucket device to perform the closing operation with a simple operation and can prevent the bucket device from opening during the closing operation. This makes it possible to prevent load spillage from the bucket device during the closing operation with a simple operation.

[0009] In the synchronized control mode, the payout of the support rope and the open / close rope can be performed based on a specific payout operation, which is either the support-side payout operation or the open / close-side payout operation. When the control mode is set to the synchronized control mode, the specific payout operation is performed, and the open / close state determination unit determines that the bucket assembly is in the closed state, the drum operation control unit preferably sets the target payout amount relative difference value based on the set value, calculates the payout amount relative difference, calculates the deviation between the target payout amount relative difference value and the payout amount relative difference, and outputs a command signal to control the operation of the support drum and the open / close drum so that the deviation approaches zero, thereby lowering the bucket assembly while maintaining the closed state of the bucket assembly. With this configuration, the bucket assembly can be closed and lowered with a simple operation by an operator, and opening of the bucket assembly during the closing and lowering operation can be prevented. This makes it possible to prevent load spillage from the bucket assembly during the closing and lowering operation with a simple operation.

[0010] Preferably, the open / close state determination unit is capable of determining whether the pair of buckets are in an open state, and when the control mode is set to the synchronized control mode, the specific winding operation is being performed, and the open / close state determination unit determines that the bucket assembly is in the open state, the drum operation control unit sets a second target value for relative difference in payout amounts that is a target value for maintaining the pair of buckets at a predetermined opening degree, calculates the relative difference in payout amounts, calculates a second deviation that is the deviation between the second target value for relative difference in payout amounts and the relative difference in payout amounts, and outputs a command signal such that the second deviation approaches zero, thereby controlling the operation of the support drum and the opening / closing drum, thereby raising the bucket assembly while maintaining the open state of the bucket assembly. With this configuration, a simple operation by the operator allows the bucket assembly to perform an open-up operation while maintaining the opening degree of the bucket assembly at a predetermined opening degree. As a result, the open state of the bucket assembly is maintained upon completion of the open-up operation, allowing the operator to immediately perform the next operation, improving workability.

[0011] In the synchronized control mode, it is preferable that the support rope and the opening / closing rope can be let out based on a specific let-out operation, which is either the support side let-out operation or the opening / closing side let-out operation, the open / closed state determination unit can determine whether the pair of buckets are in an open state, and when the control mode is set to the synchronized control mode, the specific let-out operation is performed, and the open / closed state determination unit determines that the bucket device is in the open state, the drum operation control unit sets a second target value of relative difference in payout amount, which is a target value for maintaining the pair of buckets at a predetermined opening degree, calculates the relative difference in pay-out amount, calculates a second deviation, which is the deviation between the second target value of relative difference in pay-out amount and the relative difference in pay-out amount, and outputs a command signal such that the second deviation approaches zero, thereby controlling the operations of the support drum and the open / close drum, thereby lowering the bucket device while maintaining the open state of the bucket device. With this configuration, the operator can perform the opening and lowering operation of the bucket device while maintaining the opening degree of the bucket device at a predetermined opening degree through a simple operation.As a result, the bucket device remains open when the opening and lowering operation is completed, allowing the operator to immediately perform the next operation, improving workability.

[0012] Preferably, the control mode setting unit is configured to be able to set the control mode to one of a plurality of modes including the synchronized control mode and the non-synchronized control mode, and the non-synchronized control mode is a control mode that allows the bucket apparatus to perform an operation that includes changing the open / closed state of the pair of buckets based on a predetermined specific operation. With this configuration, switching between the synchronized control mode and the non-synchronized control mode can be performed by the control mode setting unit, making it possible to continuously perform a series of tasks that include bucket apparatus operation performed in the synchronized control mode and bucket apparatus operation performed in the non-synchronized control mode, thereby improving the operability of the tasks.

[0013] It is preferable that the open / close state determination unit determines whether the pair of buckets are in a closed state based on a difference between the support side extension amount and the open / close side extension amount. [Effects of the Invention]

[0014] As described above, according to the present disclosure, a bucket control device is provided for a construction machine that enables the operator to perform a closing operation on the bucket device with a simple operation, and that can prevent the bucket device from opening during the closing operation. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a side view showing a crane equipped with a bucket control device according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a block diagram showing an outline of the functional configuration of the bucket control device. [Figure 3] FIG. 2 is a diagram showing a hydraulic circuit provided in the crane. [Figure 4] 4A and 4B are diagrams for explaining the opening and closing operation of a bucket device provided in the crane. [Figure 5] 10A and 10B are diagrams for explaining loads acting on support ropes and opening / closing ropes connected to the bucket device. [Figure 6] 4 is a flowchart showing a calculation control operation performed by a controller provided in the crane. [Figure 7] 4 is a flowchart showing a calculation control operation performed by the controller. [Figure 8] FIG. 2 is a block diagram showing the arithmetic and control operations performed by the controller. [Figure 9] 4 is a flowchart showing a calculation control operation performed by the controller. DETAILED DESCRIPTION OF THE INVENTION

[0016] Preferred embodiments of the present disclosure will now be described with reference to the drawings.

[0017] 1 shows a crane 100, which is a construction machine according to the embodiment. The crane 100 includes a lower body 101, an upper rotating body 102 rotatably supported on the lower body 101, a hoisting member 104 supported on the upper rotating body 102 so as to be able to rise and fall, a first point sheave 105 and a second point sheave 106 attached to the tip of the hoisting member 104, a plurality of winches arranged on the lower body 101 or the upper rotating body 102, a bucket unit 10, and a bucket control device.

[0018] The lower body 101 is equipped with a traveling device such as a crawler traveling device and is configured to be self-propelled. However, the lower body may be configured as a structure such as a support platform that rotatably supports the upper rotating body 102 and is not self-propelled. The upper rotating body 102 includes a rotating frame 103 rotatably attached to the lower body 101, a cabin supported on the front part of the rotating frame 103, and a counterweight supported on the rear part of the rotating frame 103. The multiple winches include a first winch WC1, a second winch WC2, and a luffing winch WC3.

[0019] The hoisting member 104 is composed of a boom supported on the revolving frame 103 so that it can be raised or lowered. However, the hoisting member may also include a boom and a jib rotatably supported at the tip of the boom. A gantry 107 is erected on the revolving frame 103. A lower spreader 110 is disposed at the upper end of the gantry 107. One end of a guy line 108 is connected to the tip of the hoisting member 104, and the other end of the guy line 108 is connected to an upper spreader 109. The lower spreader 110 and the upper spreader 109 are disposed spaced apart from each other. A hoisting rope 111 is reeled around the lower spreader 110 and the upper spreader 109. The hoisting winch WC3 is disposed on the revolving frame 103 and has a winch drum DR3 around which the hoisting rope 111 is wound. The hoisting winch WC3 winds or unwinds the hoisting rope 111 to reduce or increase the distance between the upper spreader 109 and the lower spreader 110. As the distance between them decreases or increases, the hoisting member 104 is raised or lowered.

[0020] Fig. 2 is a block diagram showing the functional configuration of the bucket control device. Fig. 3 is a diagram showing a hydraulic circuit provided in the crane 100.

[0021] The first winch WC1 and the second winch WC2 are driven to open, close, and raise and lower the bucket apparatus 10. Specifically, as shown in FIGS. 1 to 3, the first winch WC1 has a first winch drum DR1 around which a first winch rope R1 is wound, a first winch motor 34 connected to the first winch drum DR1, a first clutch brake 40A, and a reducer 47. Similarly, the second winch WC2 has a second winch drum DR2 around which a second winch rope R2 is wound, a second winch motor 35 connected to the second winch drum DR2, a second clutch brake 40B, and a reducer 47. The first clutch brake 40A and the second clutch brake 40B constitute a clutch brake mechanism 40. The first winch rope R1 is an opening / closing rope for opening and closing the bucket apparatus 10, and the second winch rope R2 is a support rope for supporting the bucket apparatus 10. The first winch drum DR1 is an opening / closing drum that pays out and takes up the opening / closing rope, and the second winch drum DR2 is a support drum that pays out and takes up the support rope.

[0022] The first winch drum DR1 is supported by a support member (not shown) so as to be rotatable about a horizontal axis to enable the first winch rope R1 to be let out and reeled in. The second winch drum DR2 is supported by a support member (not shown) so as to be rotatable about a horizontal axis to enable the second winch rope R2 to be let out and reeled in.

[0023] The first point sheave 105 and the second point sheave 106 are arranged side by side on the left and right, and are attached to the tip of the hoisting member 104. The first winch rope R1 is wound around the first point sheave 105 and hangs down from the first point sheave 105. The second winch rope R2 is wound around the second point sheave 106 and hangs down from the second point sheave 106. The lower ends (tips) of the first and second winch ropes R1, R2 are connected to the bucket device 10.

[0024] The bucket apparatus 10 is a work apparatus known as a clamshell bucket. The right diagram in Fig. 4 shows the bucket apparatus 10 in an open state, and the left diagram in Fig. 4 shows the bucket apparatus 10 in a closed state. The bucket apparatus 10 includes an upper member 11, a lower member 16 arranged below the upper member 11, a pair of link members 12, 12, a pair of buckets 13, 13, a lower sheave 14, and an upper sheave 15.

[0025] The pair of link members 12, 12 are arranged at a distance from each other in the horizontal direction. The upper ends of the pair of link members 12, 12 are each connected to the upper member 11 so as to be rotatable about a horizontal axis. The lower end of one of the pair of link members 12, 12 is connected to one of the pair of buckets 13, 13 so as to be rotatable about a horizontal axis, and the lower end of the other of the pair of link members 12, 12 is connected to the other of the pair of buckets 13, 13 so as to be rotatable about the horizontal axis.

[0026] The lower sheave 14 is supported by the lower member 16 so as to be rotatable about a horizontal axis. Each of the pair of buckets 13 has a supported portion supported by the lower member 16 so as to be rotatable about a horizontal axis. The upper sheave 15 is supported by the upper member 11 so as to be rotatable about a horizontal axis.

[0027] The pair of buckets 13, 13 have a storage space capable of containing transported objects such as soil and sand. The pair of buckets 13, 13 can be displaced between a state in which the lower ends of the buckets 13, 13 are adjacent to each other (the closed state) and a state in which the lower ends of the buckets 13, 13 are horizontally separated (the open state) by rotating about the supported portion. The pair of link members 12, 12 support the buckets 13, 13 and rotate relative to the upper member 11 in accordance with the displacement of the buckets 13, 13. By maintaining the closed state, the pair of buckets 13, 13 can hold the transported objects stored in the storage space. The pair of buckets 13, 13 can discharge the transported objects from the storage space to outside the buckets 13, 13 by switching from the closed state to the open state.

[0028] The first winch rope R1 is wound around the lower sheave 14 and the upper sheave 15, and the tip of the first winch rope R1 is fixed to either the upper member 11 or the lower member 16. The tip of the second winch rope R2 is fixed to the upper member 11. The upper member 11 is an example of a main body.

[0029] The first and second winch motors 34, 35 are hydraulic motors connected to the hydraulic pump 31. The first winch motor 34 receives hydraulic oil discharged from the hydraulic pump 31 and operates to rotate the first winch drum DR1 in either the forward or reverse direction, i.e., the payout direction or the retraction direction. Similarly, the second winch motor 35 receives hydraulic oil discharged from the hydraulic pump 31 and operates to rotate the second winch drum DR2 in either the forward or reverse direction, i.e., the payout direction or the retraction direction. This allows the first winch WC1 and the second winch WC2 to cooperate to open, close, and raise / lower the bucket unit 10. The hydraulic pump 31 is driven by a drive source such as an engine (not shown).

[0030] The reducer 47 of the first winch WC1 reduces the rotational speed of the first winch motor 34 and transmits the driving force (rotational force) from the first winch motor 34 to the first winch drum DR1. The reducer 47 of the second winch WC2 reduces the rotational speed of the second winch motor 35 and transmits the driving force (rotational force) from the second winch motor 35 to the second winch drum DR2. Each of these reducers 47 has, for example, a planetary gear mechanism.

[0031] The first clutch brake 40A can be switched between a connected state in which the driving force of the first winch motor 34 can be transmitted to the first winch drum DR1, and a free state in which the first winch rope R1 can be reeled out from the first winch drum DR1 by the weight of the bucket unit 10. The first clutch brake 40A can adjust the degree of connection between the first winch motor 34 and the first winch drum DR1 between the connected state and the free state.

[0032] Similarly, the second clutch brake 40B can be switched between a connected state in which the driving force of the second winch motor 35 can be transmitted to the second winch drum DR2, and a free state in which the second winch rope R2 can be reeled out from the second winch drum DR2 by the weight of the bucket unit 10. The second clutch brake 40B can adjust the degree of coupling between the second winch motor 35 and the second winch drum DR2 between the connected state and the free state.

[0033] The connected state is a state in which the first and second winch ropes R1, R2 can be reeled out and wound up by the driving force of the first and second winch motors 34, 35. That is, when the first and second winch motors 34, 35 are driven in the connected state, the driving force of the first and second winch motors 34, 35 is transmitted to the first and second winch drums DR1, DR2, respectively, via the reducers 47, 47. When the first and second winch drums DR1, DR2 rotate, the first and second winch ropes R1, R2 are reeled out or wound up.

[0034] The free state is a state in which the first and second winch ropes R1, R2 can be reeled out from the first and second winch drums DR1, DR2 by the tension of the first and second winch ropes R1, R2, i.e., a state in which the bucket device 10 can freely fall. In other words, the free state is a state in which the first and second winch ropes R1, R2 can be reeled out from the first and second winch drums DR1, DR2 without rotating the first and second winch motors 34, 35 in the reeling directions of the first and second winch ropes R1, R2.

[0035] The first clutch brake 40A is capable of applying a first braking force to the first winch drum DR1, i.e., braking the first winch drum DR1. Similarly, the second clutch brake 40B is capable of applying a second braking force to the second winch drum DR2, i.e., braking the second winch drum DR2.

[0036] When the first braking force acting on the rotation of the first winch drum DR1 exceeds a predetermined magnitude, the first winch drum DR1 is braked, making it impossible to reel out the first winch rope R1 from the first winch drum DR1. Similarly, when the second braking force acting on the rotation of the second winch drum DR2 exceeds a predetermined magnitude, the second winch drum DR2 is braked, making it impossible to reel out the second winch rope R2 from the second winch drum DR2. Therefore, the first braking force of the first clutch brake 40A and the second braking force of the second clutch brake 40B can keep the bucket unit 10 stationary without allowing it to fall freely, and can also stop the bucket unit 10 that is falling freely.

[0037] In this embodiment, each of the first clutch brake 40A and the second clutch brake 40B is a so-called wet brake, and includes a piston 42 driven by hydraulic pressure applied from a pilot hydraulic source P, and a plurality of brake discs 41 (a plurality of clutch plates). Each of the plurality of brake discs 41 is, for example, a friction plate immersed in hydraulic oil.

[0038] The multiple brake discs 41 can be switched between a state in which the multiple brake discs 41 are in contact with one another and a state in which the multiple brake discs 41 are separated from one another by operation of the piston 42. Each of the first clutch brake 40A and the second clutch brake 40B is in the free state when the multiple brake discs 41 are separated from one another, which allows the bucket apparatus 10 to descend (free fall) under its own weight. Furthermore, each of the first clutch brake 40A and the second clutch brake 40B is in the connected state when the multiple brake discs 41 are in contact with one another.

[0039] More specifically, each of the first clutch brake 40A and the second clutch brake 40B includes a spring 46, each of which defines a pair of oil chambers 43, 44, and the piston 42 includes a flange 45 that separates the pair of oil chambers 43, 44. When the same hydraulic pressure is applied to the pair of oil chambers 43, 44 from the pilot hydraulic source P, the spring 46 biases the piston 42 so that the multiple brake discs 41 are in contact with each other. When the hydraulic pressure applied to one oil chamber 44 from the pilot hydraulic source P becomes greater than the hydraulic pressure applied to the other oil chamber 43 by a predetermined amount or more, the multiple brake discs 41 are separated from each other.

[0040] The bucket control device is a device for opening / closing and raising / lowering the bucket device 10 by controlling the drive of the first winch drum DR1 and the second winch drum DR2. This bucket control device includes a first control valve 32, a second control valve 33, a first delivery proportional valve 61A, a first winding proportional valve 61B, a second delivery proportional valve 63A, a second winding proportional valve 63B, a first braking proportional valve 62, a second braking proportional valve 64, multiple operating devices, and a controller 70. In this embodiment, each of the proportional valves 61A, 61B, 62, 63A, 63B, and 64 is an electromagnetic proportional pressure reducing valve.

[0041] The first control valve 32 is interposed between the hydraulic pump 31 and the first winch motor 34, and the second control valve 33 is interposed between the hydraulic pump 31 and the second winch motor 35. Each of the first and second control valves 32, 33 is formed by a hydraulic pilot switching valve having a pair of pilot ports.

[0042] The pair of pilot ports are a payout pilot port and a winding pilot port. When pilot pressure is not applied to both pilot ports, each of the first and second control valves 32, 33 is held in a neutral position and isolates the winch motor (hereinafter referred to as the "corresponding winch motor") corresponding to that control valve from the hydraulic pump 31. When pilot pressure is applied to the payout pilot port, each of the first and second control valves 32, 33 opens to form an oil passage for rotating the corresponding winch motor in the payout direction, i.e., an oil passage for supplying hydraulic oil from the hydraulic pump 31 to the corresponding winch motor in the payout direction. When pilot pressure is applied to the winding pilot port, each of the first and second control valves 32, 33 opens to form an oil passage for rotating the corresponding winch motor in the winding direction, i.e., an oil passage for supplying hydraulic oil from the hydraulic pump 31 to the corresponding winch motor in the winding direction. The opening degree of each of the first and second control valves 32, 33 increases with an increase in the pilot pressure so as to allow hydraulic oil to flow at a flow rate corresponding to the pilot pressure input to the control valve.

[0043] The first payout proportional valve 61A is interposed between a pilot hydraulic source (not shown) and a payout pilot port of the first control valve 32, and opens to allow a pilot pressure proportional to the first payout command to be input to the payout pilot port as a first payout command, which is an electrical signal, is input to the proportional valve 61A from the controller 70. The first winding proportional valve 61B is interposed between the pilot hydraulic source and the winding pilot port of the first control valve 32, and opens to allow a pilot pressure proportional to the first winding command to be input to the winding pilot port as a first winding command, which is an electrical signal, is input to the proportional valve 61B from the controller 70.

[0044] Similarly, the second payout proportional valve 63A is interposed between a pilot hydraulic source (not shown) and the payout pilot port of the second control valve 33, and opens to allow a pilot pressure proportional to the second payout command to be input to the payout pilot port as a second payout command, which is an electrical signal, is input to the proportional valve 63A from the controller 70. The second retraction proportional valve 63B is interposed between the pilot hydraulic source and the retraction pilot port of the second control valve 33, and opens to allow a pilot pressure proportional to the second retraction command to be input to the retraction pilot port as a second retraction command, which is an electrical signal, is input to the proportional valve 63B from the controller 70.

[0045] As described above, the first control valve 32, the first payout proportional valve 61A, and the first take-up proportional valve 61B constitute a first speed regulator that changes the flow rate and direction of hydraulic oil flowing into the first winch motor 34 in response to commands input to the proportional valves 61A and 61B. In other words, the first speed regulator changes the speed at which the first winch motor 34 rotates the first winch drum DR1. Similarly, the second control valve 33, the second payout proportional valve 63A, and the second take-up proportional valve 63B constitute a second speed regulator that changes the flow rate and direction of hydraulic oil flowing into the second winch motor 35 in response to commands input to the proportional valves 63A and 63B. In other words, the second speed regulator changes the speed at which the second winch motor 35 rotates the second winch drum DR2.

[0046] First brake proportional valve 62 is interposed between pilot hydraulic source P and first clutch brake 40A, and opens to allow hydraulic pressure (first pilot pressure) proportional to the first brake command, which is an electrical signal, to be input to oil chamber 43 of first clutch brake 40A as the first brake command is input to proportional valve 62 from controller 70. In this way, first brake proportional valve 62 can switch the state of first clutch brake 40A between the free state and the connected state.

[0047] Similarly, second brake proportional valve 64 is interposed between pilot hydraulic source P and second clutch brake 40B, and opens to allow hydraulic pressure (second pilot pressure) proportional to the second brake command to be input to oil chamber 43 of second clutch brake 40B as a second brake command, which is an electrical signal, is input to proportional valve 64 from controller 70. In this way, second brake proportional valve 64 can switch the state of second clutch brake 40B between the free state and the connected state.

[0048] The multiple operating devices include a first winch operating device 51, a second winch operating device 53, a first brake operating device 52, and a second brake operating device 54. The first winch operating device 51 has a first winch operating lever 51A and a first winch operating device main body 51B. The second winch operating device 53 has a second winch operating lever 53A and a second winch operating device main body 53B. The first brake operating device 52 has a first brake operating pedal 52A and a first brake operating device main body 52B. The second brake operating device 54 has a second brake operating pedal 54A and a second brake operating device main body 54B. The first winch operating device 51 is an example of an opening / closing side winch operating device, and the second winch operating device 53 is an example of a support side winch operating device. The first brake operation device 52 is an example of an opening / closing side brake operation device, and the second brake operation device 54 is an example of a supporting side brake operation device.

[0049] In the following description, the first winch drum DR1 may be referred to as an opening / closing drum or a main hoist drum, and the second winch drum DR2 may be referred to as a support drum or an auxiliary hoist drum. The first winch operation lever 51A may be referred to as a main hoist lever, and the second winch operation lever 53A may be referred to as an auxiliary hoist lever. The first brake operation pedal 52A may be referred to as a main hoist pedal, and the second brake operation pedal 54A may be referred to as an auxiliary hoist pedal. The first winch rope R1 may be referred to as an opening / closing rope or a main hoist rope, and the second winch rope R2 may be referred to as a support rope or an auxiliary hoist rope. In the crane 100, instead of the bucket unit 10, a main hoisting hook (not shown) may be attached to the end of the first winch rope R1 (main hoisting rope), and an auxiliary hoisting hook (not shown) may be attached to the end of the second winch rope R2 (auxiliary hoisting rope). The "main hoist" is mainly used for heavy loads to hoist heavy loads, while the "auxiliary hoist" is mainly used for auxiliary purposes to hoist light loads.

[0050] The first winch operation lever 51A is an operating member to which a first rotation operation is applied by the operator to specify the drive speed (rotation speed) of the first winch drum DR1. Specifically, the first winch operation lever 51A is provided with either a first reeling operation (an example of an opening / closing-side reeling operation) for rotating the first winch drum DR1 (opening / closing drum) in a reeling direction so as to reel out the first winch rope R1 (opening / closing rope), or a first winding operation (an example of an opening / closing-side winding operation) for rotating the first winch drum DR1 in a winding direction so as to wind up the first winch rope R1. The first reeling operation (opening / closing-side reeling operation) is an example of a specific reeling operation. The first winding operation (opening / closing-side winding operation) is an example of a specific winding operation.

[0051] The first winch operating device main body 51B inputs a command signal to the controller 70 to command a rotational speed corresponding to the amount of operation of the first rotation operation (opening / closing side payout operation or opening / closing side retraction operation) applied to the first winch operating lever 51A.

[0052] Similarly, the second winch operation lever 53A is an operation member to which the operator applies a second rotation operation for specifying the drive speed (rotation speed) of the second winch drum DR2. Specifically, the second winch operation lever 53A is applied, as the second rotation operation, with either a second reeling operation (support-side reeling operation) for rotating the second winch drum DR2 (support drum) in the reeling direction so as to reel out the second winch rope R2 (support rope), or a second winding operation (support-side winding operation) for rotating the second winch drum DR2 in the winding direction so as to wind up the second winch rope R2.

[0053] The second winch operating device main body 53B inputs a command signal to the controller 70 to command a rotation speed corresponding to the amount of operation of the second rotation operation (support side payout operation or support side winding operation) applied to the second winch operating lever 53A.

[0054] The first brake operation pedal 52A is an operating member to which the operator applies a first pedal operation (an example of an opening / closing side brake operation) to specify a first brake force (an example of an opening / closing side brake force) for the first winch drum DR1 (opening / closing drum). The first brake operation device main body 52B inputs a command signal to the controller 70 to command a brake force of a magnitude corresponding to the amount of first pedal operation applied to the first brake operation pedal 52A.

[0055] The second brake operation pedal 54A is an operating member to which the operator applies a second pedal operation (an example of a support-side brake operation) to specify a second brake force (an example of a support-side brake force) for the second winch drum DR2 (support drum). The second brake operation device main body 54B inputs, to the controller 70, a command signal for commanding a brake force of a magnitude corresponding to the amount of second pedal operation applied to the second brake operation pedal 54A.

[0056] 2, the bucket control device further includes a first rotation sensor 81, a second rotation sensor 82, and a control mode setting unit. In this embodiment, the control mode setting unit includes an asynchronous control mode switch 90 and a bucket assist mode switch 91. The first rotation sensor 81 is an example of an opening / closing side detector, and the second rotation sensor 82 is an example of a support side detector.

[0057] The first rotation sensor 81 generates a first detection signal regarding a first rotation amount ωm, which is the rotation amount of the first winch drum DR1, and inputs the first detection signal to the controller 70. The second rotation sensor 82 generates a second detection signal regarding a second rotation amount ωa, which is the rotation amount of the second winch drum DR2, and inputs the second detection signal to the controller 70. Note that the first rotation sensor 81 may be a sensor that generates a detection signal regarding the rotation amount of the first point sheave 105 instead of the rotation amount of the first winch drum DR1, and the second rotation sensor 82 may be a sensor that generates a detection signal regarding the rotation amount of the second point sheave 106 instead of the rotation amount of the second winch drum DR2.

[0058] In this embodiment, the controller 70 sets the control mode by the controller 70 to one of a plurality of predetermined control modes based on a command signal input from the control mode setting unit. In this embodiment, the plurality of control modes include a bucket assist mode and a non-assist mode, and the bucket assist mode includes a synchronized control mode and a non-synchronized control mode. The plurality of control modes may further include other control modes.

[0059] The bucket assist mode is a control mode in which the controller 70 executes assist control to assist the operator so that the operator can perform at least one of opening / closing and lifting / lowering operations of the bucket device 10 with a simple operation. The non-assist mode is a control mode in which the above-mentioned assist control is not executed. The assist control includes main / auxiliary synchronization control, free synchronization control, bucket static closing control, excavation control, and bucket static opening control. These controls will be described later.

[0060] In this embodiment, when the bucket assist mode switch 91 is in the on state, the control mode is set to the bucket assist mode, and when the bucket assist mode switch 91 is in the off state, the control mode is set to the non-assisted mode. When the non-synchronous control mode switch 90 is in the on state in the bucket assist mode, the control mode is set to the non-synchronous control mode, and when the non-synchronous control mode switch 90 is in the off state in the bucket assist mode, the control mode is set to the synchronous control mode. Specifically, this is as follows.

[0061] The bucket assist mode switch 91 can set the control mode controlled by the controller 70 to bucket assist mode. When an operator turns on the bucket assist mode switch 91, the bucket assist mode switch 91 inputs an on command signal corresponding to the on operation to the controller 70, and the controller 70 sets the control mode to the bucket assist mode. When the on operation is not performed on the bucket assist mode switch 91, the controller 70 does not set the control mode to the bucket assist mode, but sets the control mode to another predetermined control mode (for example, a non-assist mode). The bucket assist mode switch 91 may be, for example, an input device provided on a monitor such as a touch panel located inside the cabin, or may be an input device having a push button located inside the cabin (for example, a push button provided on an operating member such as an operating lever).

[0062] The asynchronous control mode switch 90 can set the control mode by the controller 70 to the asynchronous control mode. When the control mode is set to the bucket assist mode and an on operation for the asynchronous control mode is applied to the asynchronous control mode switch 90 by the operator, the asynchronous control mode switch 90 inputs an on command signal corresponding to the on operation to the controller 70, and the controller 70 sets the control mode to the asynchronous control mode. When the control mode is set to the bucket assist mode and the on operation is not applied to the asynchronous control mode switch 90, the controller 70 sets the control mode to the synchronous control mode. The asynchronous control mode switch 90 may be, for example, an input device having a push button located in the cabin, or may be an input device provided on a monitor such as a touch panel located in the cabin. The push button may be located on an operating member such as an operating lever.

[0063] In this embodiment, in the synchronized control mode, synchronized controls such as main and auxiliary synchronized control and free synchronized control, which will be described later, are performed. In addition, in the non-synchronized control mode, non-synchronized controls such as bucket stationary closing control, excavation control, and bucket stationary opening control, which will be described later, are performed. The non-synchronized control mode is a control mode that enables the bucket device 10 to perform operations that include changing the open / closed state of the pair of buckets 13, 13 based on specific operations that are set in advance.

[0064] Furthermore, the control mode setting unit may include a plurality of switches (not shown) that are operated by an operator to more specifically specify the operation of the bucket apparatus 10 in specific controls such as the main and auxiliary synchronization control, the free synchronization control, the bucket stationary closing control, the excavation control, and the bucket stationary opening control, and each of the plurality of switches may be configured to input a command signal corresponding to the operation to the controller 70. The operations of the bucket apparatus 10 in the synchronization control mode include a "close-up" operation that is an operation to raise the bucket apparatus 10 in a closed state, an "open-up" operation that is an operation to raise the bucket apparatus 10 in an open state, an "open-down" operation that is an operation to lower the bucket apparatus 10 in an open state, and a "close-down" operation that is an operation to lower the bucket apparatus 10 in a closed state.

[0065] In the free tuning control in the tuning control mode, the first and second braking forces of the first and second clutch brakes 40A, 40B are adjusted based on the amount of first pedal operation (pedal operation amount) applied to the first brake operating pedal 52A.

[0066] The controller 70 controls the drive of the first winch WC1 and the second winch WC2 to open, close, and raise and lower the bucket unit 10, and as shown in Fig. 2, has an open / close state determination unit 71, a braking force adjustment unit 72, and a drum operation control unit 73. The braking force adjustment unit 72, the first brake proportional valve 62, and the second brake proportional valve 64 constitute a braking force adjustment mechanism.

[0067] The open / closed state determination unit 71 determines the open / closed state of the bucket apparatus 10. That is, the open / closed state determination unit 71 determines whether the bucket apparatus 10 is in an open state or a closed state. The open / closed state determination unit 71 in this embodiment determines the open / closed state of the bucket apparatus 10 based on the first rotation amount ωm and the second rotation amount ωa. Specifically, this is as follows.

[0068] First, the open / close state determination unit 71 estimates a first payout amount Lm, which is the payout amount of the first winch rope R1 paid out from the first winch drum DR1, based on the first rotation amount ωm, and estimates a second payout amount La, which is the payout amount of the second winch rope R2 paid out from the second winch drum DR2, based on the second rotation amount ωa. The first payout amount Lm is calculated, for example, using the following equation (1), and the second payout amount La is calculated, for example, using the following equation (2). Rm in equation (1) is the effective radius of the first winch drum DR1, and Ra in equation (2) is the effective radius of the second winch drum DR2.

[0069] Lm=Rm×ωm...Equation (1) La = Ra × ωa Equation (2) In the following description, the signs of the first and second payout amounts Lm, La when the bucket apparatus 10 is wound down (i.e., when the bucket apparatus 10 is lowered) are assumed to be positive, and the signs of the first and second payout amounts Lm, La when the bucket apparatus 10 is wound up (i.e., when the bucket apparatus 10 is raised) are assumed to be negative.

[0070] Next, the open / close state determination unit 71 calculates the relative difference (ΔL = Lm - La) between the first and second payout amounts Lm, La. For example, the state in which the bucket apparatus 10 is closed is set as the initial state, as shown in the left diagram of Fig. 4, and ΔL in this initial state is set to zero. When the bucket apparatus 10 is being wound up and down with the bucket apparatus 10 closed, the first and second payout amounts Lm, La each increase and decrease, but as long as the bucket apparatus 10 remains closed, the relationship "ΔL ≦ 0" is maintained.

[0071] On the other hand, when the bucket apparatus 10 is in an open state, the first extension amount Lm increases relatively to the second extension amount La. The open / closed state determination unit 71 can determine the opening degree (opening / closing degree) of the bucket apparatus 10, for example, as follows.

[0072] Let L1 be the distance between the upper sheave 15 and the lower sheave 14 when the bucket device 10 is in a closed state (closed state) as shown in the left diagram of Fig. 4, let L2 be the distance between the upper sheave 15 and the lower sheave 14 when the bucket device 10 is in an open state (open state) as shown in the right diagram of Fig. 4, and let N be the number of turns (number of ropes) of the first winch rope R1 reeled around the upper sheave 15 and the lower sheave 14. In this case, the relative difference ΔL is expressed by the following equation (3).

[0073] ΔL=(L2-L1)×N (3) When the bucket device 10 is in a completely open state, that is, when the bucket device 10 is in a most open state, the distance between the upper sheave 15 and the lower sheave 14 is defined as L2max, and the relative difference between the first and second payout amounts Lm, La at this time is defined as ΔLmax. In this case, ΔLmax is expressed as in the following equation (4), and the opening degree of the bucket device 10 is expressed by the following equation (5).

[0074] ΔLmax=(L2max-L1)×N (4) Opening degree of the bucket device 10=ΔL / ΔLmax (5) Therefore, the open / closed state determining unit 71 can determine the open / closed state of the bucket apparatus 10 based on the opening degree of the bucket apparatus 10 calculated as described above.

[0075] The braking force adjustment unit 72 adjusts the first braking force and the second braking force. When the control mode is set to the synchronous control mode, a first brake operation to reduce the first braking force is applied to the first brake operating pedal 52A, and the open / closed state determination unit 71 determines that the bucket apparatus 10 is in the open state, the braking force adjustment unit 72 performs the following opening / lowering control. In this opening / lowering control, the braking force adjustment unit 72 adjusts the first braking force and the second braking force so that the bucket apparatus 10 descends by its own weight while maintaining the open state of the bucket apparatus 10. Such opening / lowering control performed in response to the operation applied to the brake operating pedal is an example of free synchronous control. Furthermore, when the control mode is set to the synchronous control mode, a first brake operation to reduce the first braking force is applied to the first brake operating pedal 52A, and the open / closed state determination unit 71 determines that the bucket apparatus 10 is in the closed state, the braking force adjustment unit 72 performs the following closing / lowering control. In this closing-down control, the braking force adjustment unit 72 adjusts the first braking force and the second braking force so that the bucket apparatus 10 descends while maintaining the closed state of the bucket apparatus 10. Such closing-down control, which is executed in response to the operation of the brake operating pedal, is an example of free tuning control. The first braking operation that reduces the first braking force is, for example, an operation that reduces the pedal operation amount (depression amount) applied to the first brake operating pedal 52A.

[0076] The drum operation control unit 73 controls the operation of the first winch drum DR1 and the operation of the second winch drum DR2. In the main / auxiliary synchronization control in the synchronization control mode, the operation of the first winch drum DR1 and the operation of the second winch drum DR2 are controlled based on the first rotation operation applied to the first winch operation device 51.

[0077] Specifically, when the control mode is set to the synchronized control mode and a first extension operation is applied to the first winch operation lever 51A of the first winch operation device 51, the drum operation control unit 73 performs the following opening / lowering control or closing / lowering control. In the opening / lowering control, the drum operation control unit 73 controls the operation of the first winch drum DR1 and the operation of the second winch drum DR2 so that the bucket apparatus 10 descends while maintaining the open state of the bucket apparatus 10. In the closing / lowering control, the drum operation control unit 73 controls the operation of the first winch drum DR1 and the operation of the second winch drum DR2 so that the bucket apparatus 10 descends while maintaining the closed state of the bucket apparatus 10. Each of the opening / lowering control and closing / lowering control executed in response to the operation applied to the winch operation lever as described above is an example of main / auxiliary synchronized control.

[0078] Furthermore, when the control mode is set to the synchronized control mode and a first winding operation is applied to the first winch operation lever 51A of the first winch operation device 51, the drum operation control unit 73 performs the following opening-up control or closing-up control. In the opening-up control, the drum operation control unit 73 controls the operation of the first winch drum DR1 and the operation of the second winch drum DR2 so that the bucket unit 10 rises while maintaining the open state of the bucket unit 10. In the closing-up control, the drum operation control unit 73 controls the operation of the first winch drum DR1 and the operation of the second winch drum DR2 so that the bucket unit 10 rises while maintaining the closed state of the bucket unit 10. The opening-up control and closing-up control executed in response to the operation applied to the winch operation lever as described above are each an example of main and auxiliary synchronized control.

[0079] Fig. 5 is a diagram for explaining the loads applied to the first winch rope R1 and the second winch rope R2 connected to the bucket apparatus 10. The left diagram of Fig. 5 shows the first and second winch drums DR1, DR2, the first and second winch ropes R1, R2 wound around these winch drums DR1, DR2, and the bucket apparatus 10 to which the ends of these winch ropes R1, R2 are connected. The right diagram of Fig. 5 is a schematic diagram for explaining the balance of forces in the left diagram of Fig. 5.

[0080] The tension of the first winch rope R1 is T1 (T open / close), and the tension of the second winch rope R2 is T2 (T support). The right diagram of Fig. 5 illustrates an example in which the number of turns (number of rope turns) of the first winch rope R1 wound around the upper sheave 15 and the lower sheave 14 is four (four-way winding). As can be seen from the right diagram of Fig. 5, the tension T1 is balanced with the sum of the acting forces on the pair of left and right link members 12, 12 (left and right combined) and three times T1 (T1 x 3) (Equation (6)).

[0081] T2 = T1 × 3 + force acting on the link (total of left and right) (6) Here, assuming that the weight of the bucket device 10 is supported approximately evenly by the link members 12, 12 and the lower sheave 14, the following equation (7) is established.

[0082] Force acting on the link (total of left and right) = T1 × 4 (7) Substituting equation (7) into equation (6), we obtain the relationship shown in the following equation (8).

[0083] T2=T1×3+T1×4=T1×7 (8) Therefore, when the relationship of the following formula (9) is satisfied, the bucket device 10 opens, and when the relationship of the following formula (10) is satisfied, the bucket device 10 closes.

[0084] T2>T1×7 (9) T2 <T1×7 ···(10) Note that the right-hand sides of formulas (9) and (10), "T1 x 7," are calculation examples for the case of four ropes being hung as described above, and if the number of ropes being hung changes, the right-hand sides can be changed accordingly. Also, if the shape of the bucket device 10 changes, the right-hand sides can be changed accordingly.

[0085] Further, the tension T1 of the first winch rope R1 and the tension T2 of the second winch rope R2, and the first braking force and the second braking force have the following relationship.

[0086] Tension T1 = First brake force (opening / closing side brake force) Tension T2 = Second brake force (support side brake force) From the above, when the bucket device 10 is opened and lowered, the first braking force and the second braking force are set as shown in the following formulas (11) and (12). The first set value and the second set value are preset values, and the second set value is set to, for example, a value seven times the first set value.

[0087] First brake force (open / close brake force) < First set value (11) Second brake force (support side brake force) > Second set value (12) Furthermore, during the closing and lowering operation of the bucket device 10, the first braking force and the second braking force are set as shown in the following formulas (13) and (14).

[0088] First brake force (open / close brake force) > First set value (13) Second brake force (support side brake force) < second set value (14) As described above, the controller 70 can switch the bucket assist mode on and off based on the command signal input from the control mode setting unit, and when the bucket assist mode is on, can switch between the synchronized control mode and the non-synchronized control mode based on the command signal input from the control mode setting unit.

[0089] In this embodiment, the synchronized control mode is used when the bucket apparatus 10 is caused to perform a closing-up operation, a closing-down operation, an opening-up operation, and a closing-up operation. In the main and auxiliary synchronized control of the synchronized control mode, an operation of lowering or raising the bucket apparatus 10 is performed while maintaining the bucket apparatus 10 in an open or closed state by operating a single lever by the operator. In the free synchronized control of the synchronized control mode, an operation of lowering the bucket apparatus 10 is performed while maintaining the bucket apparatus 10 in an open or closed state by operating a single pedal by the operator.

[0090] On the other hand, in this embodiment, the non-synchronized control mode is used when the bucket apparatus 10 is made to perform an excavation operation, when the bucket apparatus 10 is made to perform an air-closing operation which is an operation of closing the bucket apparatus 10 in the air, when the bucket apparatus 10 is made to perform an air-opening operation which is an operation of opening the bucket apparatus 10 in the air, etc.

[0091] In excavation control for excavation operation in this asynchronous control mode, the second winch drum DR2 (auxiliary hoist drum) is set free, and the first winch rope R1 (opening / closing rope) is wound up by the first winch drum DR1 (main hoist drum), thereby loosening the tension on the second winch rope R2 (support rope) and causing the bucket apparatus 10 to perform an operation to close the bucket apparatus 10. As a result, in the process of closing the bucket apparatus 10 during excavation operation, the bucket apparatus 10 sinks as the excavation target, such as earth and sand, is excavated, and more of the excavation target can be stored in the bucket apparatus 10.

[0092] In the static bucket closing control for the air-closing operation in the asynchronous control mode, the second winch operation lever 53A is in the neutral position, and with the second brake operation pedal 54A stepped on (a state in which the second winch drum DR2 is braked so as to prevent rotation of the second winch drum DR2), a winding operation is applied to the first winch operation lever 51A. This makes it possible to wind up the first winch rope (opening / closing rope) without reeling out or winding up the second winch rope (support rope), and to operate the bucket unit 10 in the closing direction while maintaining the height of the bucket unit 10 in the air.

[0093] In the static bucket opening control for the air-opening operation in the asynchronous control mode, the second winch operation lever 53A is in the neutral position, the second brake operation pedal 54A is depressed (the brake is applied to the second winch drum DR2 to prevent rotation of the second winch drum DR2), and the first brake operation pedal 52A is operated to reduce (weake) the first braking force. This allows the first winch rope R1 (opening / closing rope) to be paid out without paying out or retracting the second winch rope (support rope), thereby loosening the tension on the opening / closing rope. This allows the bucket unit 10 to be operated in the opening direction while maintaining its height in the air. This air-opening operation is used, for example, in earth removal work, in which an object to be transported, such as earth and sand, held in the closed bucket unit 10 is unloaded onto a destination (e.g., the bed of a truck).

[0094] The operation of lowering the bucket assembly 10 can be performed using the driving forces of the first and second winch motors 34, 35, but it can also be performed by setting the first and second clutch brakes 40A, 40B to a free state and allowing the bucket assembly 10 to free fall. When the bucket assembly 10 is free falling, the first and second braking forces are adjusted by applying pedal operation to the first and second brake operation pedals 52A, 54A, and thereby the descent speed of the bucket assembly 10 is adjusted.

[0095] Next, the calculation and control operations performed by the controller 70 will be described with reference to FIGS.

[0096] FIG. 6 is a flowchart showing the arithmetic and control operation performed by the controller 70. As shown in FIG. 6, the controller 70 switches the synchronization control mode on and off based on a command signal input from the control mode setting unit. In step S100, the controller 70 determines whether or not a command signal for switching the synchronization control mode on and off has been input (step S100). Specifically, in step S100, the controller 70 may determine, for example, whether or not a synchronization control mode command signal, which is a command signal for setting the control mode to the synchronization control mode, has been input. Alternatively, in step S100, the controller 70 may determine, for example, whether or not a non-synchronization control mode command signal, which is a command signal for setting the control mode to the non-synchronization control mode, has been input.

[0097] When a synchronization control mode command signal is input from the control mode setting unit (YES in step S100), the controller 70 sets the control mode to the synchronization control mode. In the synchronization control mode, the controller 70 executes synchronization control such as the main / auxiliary synchronization control and the free synchronization control (step S101). On the other hand, when a non-synchronization control mode command signal is input from the control mode setting unit (NO in step S100), the controller 70 cancels the synchronization control mode and sets the control mode to the non-synchronization control mode. In the non-synchronization control mode, the controller 70 executes non-synchronization control such as the bucket static closing control, the excavation control, and the bucket static opening control (step S102).

[0098] In this embodiment, switching between the synchronous control mode and the non-synchronous control mode is performed based on an input operation input to the non-synchronous control mode switch 90. Specifically, when the operator inputs an input operation to the non-synchronous control mode switch 90 to turn off the non-synchronous control mode, the non-synchronous control mode switch 90 inputs a synchronous control mode command signal to the controller 70, and the controller 70 sets the control mode to the synchronous control mode based on the input synchronous control mode command signal and performs synchronous control (steps S100 and S101). When the operator inputs an input operation to the non-synchronous control mode switch 90 to turn on the non-synchronous control mode, the non-synchronous control mode switch 90 inputs a non-synchronous control mode command signal to the controller 70, and the controller 70 sets the control mode to the non-synchronous control mode based on the input non-synchronous control mode command signal and performs synchronous control (steps S100 and S102).

[0099] In the control device according to the present embodiment, when the bucket unit 10 is to perform an excavation operation, a mid-air closing operation, or a mid-air opening operation after an operation in the synchronized control mode (e.g., a closing-down operation, a closing-up operation, etc.), the operator can cancel (cancel) the synchronized control mode and set the control mode to the mid-air control mode simply by applying an OFF operation to turn off the synchronized control mode (an ON operation to turn on the non-synchronized control mode in this embodiment) to the non-synchronized control mode switch 90 as described above. Furthermore, when the bucket unit 10 is to perform, for example, a closing-up operation after an operation in the non-synchronized control mode (e.g., an excavation operation), the operator can cancel the non-synchronized control mode and set the control mode to the synchronized control mode simply by applying an ON operation to turn on the synchronized control mode (an OFF operation to turn off the non-synchronized control mode in this embodiment) to the non-synchronized control mode switch 90 as described above. This makes it possible to continuously and smoothly perform a series of operations including, for example, an excavation operation and a closing-up operation, improving the ease of the series of operations.

[0100] In the following, the synchronized control mode will be explained first, and then the non-synchronized control mode will be explained.

[0101] [Synchronous control mode] 7 is a flowchart showing the arithmetic control operation in the synchronization control mode performed by the controller 70. In the synchronization control mode, a command signal related to the operation amount of the first winch operation lever 51A (main winding lever) is input from the first winch operation device 51 (opening / closing side winch operation device) to the controller 70, a detection signal related to the payout amount of the first winch rope R1 (main hoisting rope) is input from the first rotation sensor 81 (opening / closing side detector) to the controller 70, and a detection signal related to the payout amount of the second winch rope R2 (auxiliary hoisting rope) is input from the second rotation sensor 82 (support side detector) to the controller 70 (step S1).

[0102] Next, the controller 70 calculates the relative difference in feed amount ΔL, which is the difference between the first feed amount Lm (opening / closing side feed amount Lm) and the second feed amount La (support side feed amount La), and calculates the opening degree (opening / closing degree) of the bucket device 10 (step S2).

[0103] Next, the controller 70 determines whether or not the main winding lever is being operated, i.e., whether or not an operation is being applied to the main winding lever (step S3). The controller 70 can determine whether or not an operation is being applied to the main winding lever based on a command signal relating to the amount of operation of the main winding lever that is input to the controller 70 in step S1, for example.

[0104] If no operation is applied to the main winding lever (NO in step S3), the controller 70 sets the command value for the proportional valve to a command value (e.g., command value = 0) that will not drive the first and second winch motors 34, 35, and inputs the command value to the first payout proportional valve 61A, the first winding proportional valve 61B, the second payout proportional valve 63A, and the second winding proportional valve 63B (step S4).

[0105] On the other hand, if the main winding lever is being operated (YES in step S3), the controller 70 determines whether this process (the process of step S5) is the first step (first cycle) from the point in time when it was determined that the main winding lever was being operated (step S5). In other words, the controller 70 determines whether the process of step S5 is being performed for the first time since it was determined in step S3 that the main winding lever was being operated.

[0106] If the controller 70 determines that the processing is the first step (YES in step S5), the open / closed state determination unit 71 determines whether the bucket apparatus 10 is in an open state or a closed state (step S7). Specifically, the open / closed state determination unit 71 may determine whether the bucket apparatus 10 is in an open state or a closed state based on the opening degree of the bucket apparatus 10 calculated in step S2. Furthermore, if an open / closed state input switch that allows the operator to input the open / closed state of the bucket apparatus 10 is provided inside the cabin, the open / closed state determination unit 71 may determine whether the bucket apparatus 10 is in an open state or a closed state based on information input by the operator via the open / closed state input switch.

[0107] When the opening / closing state determination unit 71 determines that the bucket apparatus 10 is in the closed state (YES in step S7), the drum operation control unit 73 sets the target payout amount relative difference value, which is the target value of the difference between the opening / closing side payout amount Lm and the support side payout amount La, to, for example, a closing operation set value (closing up / down set value), which is a set value previously set for the closing up operation and the closing down operation (step S8). The closing operation set value is a set value set to prevent the pair of buckets 13, 13 from opening, and is a set value related to the support side slack, which is the amount of slack in the second winch rope R2 (support rope). The closing operation set value is a value previously set so that the support rope is slightly slack when the first winch rope R1 (opening / closing rope) is taut and the bucket apparatus 10 is closed.

[0108] When the bucket apparatus 10 is being closed up or closed down in the synchronized control mode, if the bucket apparatus 10 were to open during the operation, the contents (objects to be transported) held in the bucket apparatus 10 would spill out of the bucket apparatus 10, so it is necessary to reliably maintain the closed state of the bucket apparatus 10 during the operation. If tension is applied to the support rope during the closing up or closing down operation, there is a risk that the bucket apparatus 10 will open during the operation. On the other hand, by maintaining the support rope in a slack state during the operation, it is possible to perform the closing up or closing down operation while reliably maintaining the closed state of the bucket apparatus 10.

[0109] The greater the support-side slack in the support ropes, the easier it is to maintain the closed state of the bucket apparatus 10. However, if the slack becomes too great, the bucket apparatus 10 will be supported only by the opening and closing ropes, making the bucket apparatus 10 more likely to tilt. Therefore, it is preferable that the closing operation set value be changeable. In this case, the operator inputs a change to the closing operation set value, for example, to an input device located in the cabin. This enables the operator to adjust the support-side slack in the support ropes during the closing-up or closing-down operation, depending on, for example, the type of object being transported by the bucket apparatus 10. Specifically, if the various contents (objects being transported) grasped by the bucket apparatus 10 can tolerate some spillage during transport, the closing operation set value is set to reduce the support-side slack. This allows the bucket apparatus 10 to perform the closing-down and closing-up operations while suppressing tilting of the bucket apparatus 10 and maintaining the closed state of the bucket apparatus 10 to some extent. Furthermore, if the contents (objects to be transported) grasped by the bucket apparatus 10 cannot be allowed to spill during transport, the closing operation setting value is set so that the amount of slack on the support side is large. This allows the bucket apparatus 10 to perform the closing down operation and the closing up operation while reliably maintaining the closed state of the bucket apparatus 10.

[0110] On the other hand, if the opening / closing state determination unit 71 determines that the bucket device 10 is not in a closed state (is in an open state) (NO in step S7), the drum operation control unit 73 sets the target value of the relative difference in the payout amount to, for example, an opening operation set value (set value for opening up / down) that is a set value previously set for the opening-up operation and the opening-down operation (step S9). This target value of the relative difference in the payout amount is a target value of the relative difference in the payout amount, which is the difference between the opening / closing-side payout amount Lm and the support-side payout amount La, and is a target value for maintaining the pair of buckets 13, 13 at a predetermined opening degree. The target value of the relative difference in the payout amount for the opening-up operation and the opening-down operation is an example of a second target value of the relative difference in the payout amount.

[0111] The opening operation set value may be, for example, any one of the following (A), (B), and (C).

[0112] (A) The opening operation set value may be, for example, the relative difference in the extension amount (initial detection value) in the first step (first cycle).

[0113] (B) The opening operation set value may be a predetermined opening degree corresponding value, which is a value set in advance so that the bucket device 10 is opened by a predetermined opening degree.

[0114] (C) The opening operation set value may be a fully open value that is a value that is set in advance so that the bucket device 10 is in a fully open state and the opening / closing rope is in a slack state.

[0115] When the opening operation set value is the initial detection value (case (A) above), the operation is performed while maintaining the opening degree of the bucket apparatus 10 at the time when the opening-up operation or the opening-down operation was started. When the opening operation set value is the value corresponding to the predetermined opening degree (case (B) above), when the opening-up operation or the opening-down operation is started, the controller 70 automatically changes the opening degree of the bucket apparatus 10 to the predetermined opening degree, and the operation is performed while maintaining the predetermined opening degree. Also, when the opening operation set value is the value corresponding to full opening (case (C) above), when the opening-up operation or the opening-down operation is started, the controller 70 automatically changes the relative values ​​of the main and auxiliary payout amounts so that the bucket apparatus 10 is fully open and the opening / closing rope is slack, and the operation is performed while maintaining that state.

[0116] The opening operation setting value may be configured so that the operator can change it as needed in consideration of various conditions such as the type of work and ease of use.

[0117] If the controller 70 determines that the processing of step S5 is the second step or later (second cycle or later) (NO in step S5), it maintains the target value of the relative difference between the main and auxiliary feed amounts set in the first step, step S8 (step S6).

[0118] In step S10, the drum operation control unit 73 determines a command value (corrected command value) for the proportional valve by feeding back the deviation between the target value of the relative difference in payout amount and the (current value) relative difference in payout amount and correcting the amount of operation of the main winding lever 51A, and outputs the corrected command value to the proportional valve. Specifically, in the case of a closing-up operation or an opening-up operation, that is, when the operation applied to the main winding lever is the first winding operation, the drum operation control unit 73 outputs the corrected command value calculated for the first winding proportional valve 61B to the first winding proportional valve 61B, and outputs the corrected command value calculated for the proportional valve 63B to the second winding proportional valve 63B. In addition, in the case of a closing operation or an opening operation, that is, when the operation applied to the main winding lever is the first extension operation, the drum operation control unit 73 outputs a correction command value calculated for the first extension proportional valve 61A to the first proportional valve 61A, and outputs a correction command value calculated for the second extension proportional valve 63A to the second proportional valve 63A.

[0119] Fig. 8 is a block diagram related to feedback control in the synchronized control mode. The controller 70 performs feedback control, for example, as shown in Fig. 8, in order to make the bucket assembly 10 perform a closing-up or opening-up operation for raising the bucket assembly 10 while maintaining the closed or open state of the bucket assembly 10, or a closing-down or opening-down operation for lowering the bucket assembly 10 while maintaining the closed or open state of the bucket assembly 10, by bringing the actual relative value of the main / auxiliary extension amounts closer to the target value of the relative difference in extension amounts set as described above.

[0120] Specifically, the controller 70 calculates the deviation (deviation of relative payout amounts) by subtracting the actual relative difference (current value) from the target value of relative difference of payout amounts. Next, the controller 70 performs a correction by feeding back the deviation of relative difference of payout amounts to the operation amount of the main winding lever, thereby calculating proportional valve command current values ​​for the main winding and auxiliary winding, i.e., command current values ​​to be output to the proportional valves 61A, 61B, 63A, and 63B.

[0121] For example, if the detected value (calculated value) of the opening / closing side payout amount (main winding payout amount) is Lm and the detected value (calculated value) of the support side payout amount (auxiliary winding payout amount) is La, the payout amount relative difference ΔL is calculated by subtracting the support side payout amount La from the opening / closing side payout amount Lm (ΔL = Lm - La).

[0122] Furthermore, if the target value of the relative difference in the extension amounts set as described above is ΔLr, the deviation H of the relative difference in the extension amounts is calculated by subtracting the relative difference ΔL from the target value ΔLr (H=ΔLr−ΔL).

[0123] If the detected value of the operation amount of the main winding lever is Am, for example, when PID control is performed, the command value (corrected command value) to the proportional valve 61A or 61B for the main winding lever and the command value (corrected command value) to the proportional valve 63A or 63B for the auxiliary winding lever are each calculated using, for example, the following equations: Here, K1 is the proportional gain, K2 is the integral gain, and K3 is the differential gain.

[0124] Command value to the proportional valve for the main winding lever = Am - K1 x H - K2 x (integral value of H) - K3 x (differential value of H) Command value to the proportional valve for the auxiliary winding lever = Am + K1 × H + K2 × (integral value of H) + K3 × (differential value of H) The drum operation control unit 73 outputs the command value calculated as described above, i.e., a command signal that brings the deviation H closer to zero, to the corresponding proportional valve to control the operation of the support drum DR2 and the opening / closing drum DR1, thereby making it possible to raise or lower the bucket device 10 while maintaining the closed state of the bucket device 10.

[0125] [Asynchronous control mode] Next, the non-synchronous control mode will be described. As described above, when a command signal for specifying that the synchronous control mode is turned off, i.e., a command signal for turning on the non-synchronous control mode, is input from the non-synchronous control mode switch 90 (NO in step S100 in FIG. 6), the controller 70 cancels the synchronous control mode and sets the control mode to the non-synchronous control mode (step S102 in FIG. 6).

[0126] FIG. 9 is a flowchart showing the calculation and control operation performed by the controller 70 in the non-synchronization control mode.

[0127] In excavation control, the second winch drum DR2 (auxiliary hoist drum) is set free, and the main hoist drum winds up the opening and closing rope, thereby loosening the tension on the support rope and causing the bucket apparatus 10 to perform an operation to close the bucket apparatus 10. As a result, in the process of closing the bucket apparatus 10 during the excavation operation, the bucket apparatus 10 sinks as the excavation target is excavated, and more of the excavation target can be stored within the bucket apparatus 10.

[0128] Specifically, when a winding operation is applied to the first winch operation lever 51A (YES in step S31) and the first brake operation pedal 52A is operated to reduce (weaken) the first braking force (NO in step S32), the controller 70 performs excavation control to operate the bucket assembly 10 in the closing direction and reduce the second braking force (the tension of the second winch rope R2) in accordance with a reduction in the amount of operation of the first brake operation pedal 52A (step S34). With this excavation control, when excavating soil with the bucket assembly 10, the bucket assembly 10 can be operated so that the bucket assembly 10 sinks while excavating. This control makes it possible to grip more soil than bucket stationary closing control, which closes the bucket assembly 10 without changing its height. In the excavation control, the winding operation applied to the first winch operation lever 51A and the operation of the first brake operation pedal 52A to reduce the first braking force are examples of specific operations.

[0129] To close the bucket in mid-air (static bucket closing control), the second winch operation lever 53A (auxiliary winding lever) is set to the neutral position, and a winding operation is applied to the first winch operation differential lever 51A (main winding lever), thereby fixing the support side while winding up the opening / closing side, thereby performing the bucket closing operation in mid-air.

[0130] Specifically, when a winding operation is applied to the first winch operation lever 51A (YES in step S31) and the first brake operation pedal 52A is depressed (YES in step S32), the controller 70 performs bucket stationary closing control to operate the bucket device 10 in the closing direction while maintaining the height of the bucket device 10. In the bucket stationary closing control, the winding operation applied to the first winch operation lever 51A and the depression of the first brake operation pedal 52A are examples of specific operations.

[0131] Furthermore, the bucket discharge operation is performed by setting the auxiliary hoist lever to the neutral position and freeing the main hoist drum to release the tension on the opening and closing rope (opening and closing side wire), which allows the bucket unit 10 to be opened in the air.

[0132] Specifically, when a winding operation is not applied to the first winch operation lever 51A (NO in step S31) and the first brake operation pedal 52A is operated to reduce (weaken) the first braking force (YES in step S35), the controller 70 performs bucket static opening control such that the bucket apparatus 10 opens while maintaining the height of the bucket apparatus 10. In this bucket static opening control, the bucket apparatus 10 is supported by the second winch rope R2 (auxiliary hoisting rope), while the first winch drum DR1 is set free and the tension of the first winch rope R1 is reduced, thereby performing an operation to open the bucket apparatus 10 in the air. In the bucket static opening control, the operation of applying the first brake operation pedal 52A to reduce the first braking force is an example of a specific operation.

[0133] As described above, the bucket control device according to this embodiment allows the operator of the crane 100 to perform various operations, such as closing the bucket assembly 10, with simple operations, and also prevents the bucket assembly 10 from opening during the closing operation. This bucket control device automatically synchronizes the operation of the opening / closing drum and the support drum with a single operating lever, reducing operator fatigue and enabling even unskilled operators to work at a relatively high speed. In addition, because the amount of slack on the support side is automatically corrected, there is no need to adjust the amount of slack on the support side, improving workability.

[0134] Furthermore, when the bucket apparatus 10 is being closed or lowered, it can be wound up without applying tension to the support rope, and synchronized winding up or synchronized winding down can be achieved reliably without causing any load to spill when the bucket apparatus 10 is being closed or lowered. Also, when the bucket apparatus 10 is being opened or lowered, synchronized winding up or synchronized winding down can be achieved while the bucket apparatus 10 is maintained in an open position (for example, the initial position), and the opening degree (open / closed degree) of the bucket apparatus 10 is maintained even after synchronized winding up or synchronized winding down, so the next operation can be started immediately, improving workability.

[0135] Specifically, when the bucket assembly 10 is raised while closing, tension on the support ropes poses a risk of the bucket assembly 10 opening during the closing operation. Therefore, to ensure reliable closing, the support ropes are left loose, maintaining tension on the opening / closing ropes while the opening / closing drum and the support drum are synchronized. However, excessive loosening of the support ropes would cause the bucket assembly 10 to tilt. Therefore, if spillage of the contents of the bucket assembly 10 is unacceptable, the support ropes are sufficiently loosened to allow the opening / closing drum and the support drum to operate in synchronization, thereby lifting or lowering the bucket assembly 10. On the other hand, if some spillage of the contents from the bucket assembly 10 is acceptable, the amount of slack in the support ropes is reduced, and the opening / closing drum and the support drum are synchronized to lift or lower the bucket assembly 10. Conventional technology does not perform synchronization control that takes into account the amount of slack on the support side, which makes operation of the operating lever complicated, resulting in problems such as fatigue due to operation and reduced operating speed for unskilled operators.

[0136] Furthermore, the typical operational flow of the bucket apparatus 10 is to perform an excavation operation with the bucket apparatus 10, followed by a closing operation of the bucket apparatus 10. During excavation, the opening / closing drum reels in the opening / closing rope, while the support drum is set in a free state. By setting the support drum in a free state, the bucket apparatus 10 sinks into the excavation target, such as the ground, due to its own weight as it excavates the target, allowing it to grasp a larger amount of the excavation target. In this type of excavation operation, if the opening / closing drum continues to reel in the support rope even after the bucket apparatus 10 is completely closed, the support rope will become even looser. If the reeling operation by the support drum is started when the support rope has become somewhat loose, both the opening / closing rope and the support rope will be reeled in, and the bucket apparatus 10 will be reeled in while the support rope remains loose. In such a case, for example, if the timing of the start of the reeling operation by the support drum is delayed, the support rope will become excessively loose, resulting in the bucket apparatus being supported only by the opening / closing rope, which could cause the bucket apparatus to tilt. Furthermore, if the support rope becomes excessively slack, it is necessary to temporarily stop the winding operation of the opening / closing drum and wind up only the support drum to remove the slack, which increases unnecessary operations and reduces the cycle time. On the other hand, if the timing of starting the winding operation of the support drum is too early, there is a risk that the support rope will not have enough slack, causing tension on the support rope and causing the bucket device 10 to open during the closing operation. In this case, it is necessary to wind up only the opening / closing drum to create slack in the support rope, which similarly increases unnecessary operations and reduces the cycle time. The bucket control device according to this embodiment automatically corrects the amount of slack on the support side during the closing-down operation and the closing-up operation, eliminating the need to adjust the amount of slack on the support side and thereby solving the above-mentioned problems.

[0137] Furthermore, conventional control devices (such as the control device in Patent Document 1) do not include a means for determining whether the bucket device is open or closed, and do not take into consideration the need to slacken the support ropes to prevent tension from being applied when the bucket device is closed.

[0138] Furthermore, when performing operations such as excavation operations or closing the bucket device 10 in the air, it is necessary to cancel the synchronized control mode. In the bucket control device of this embodiment, this cancellation function is realized by mode switching, making it possible to continuously perform a series of operations including excavation operations in the non-synchronized control mode and closing operations in the synchronized control mode, thereby improving workability.

[0139] The present disclosure is not limited to the above-described embodiments. The present disclosure includes, for example, the following embodiments.

[0140] (A) Crane specifications The crane according to the embodiment shown in Fig. 1 does not have a jib or struts, but the specifications of the crane are not limited to those shown in Fig. 1. The crane according to the present disclosure may be a luffing crane equipped with a jib, front struts, and rear struts, or may be a fixed jib crane equipped with a jib and one strut. The crane according to the present disclosure may also be a crane equipped with a mast instead of a gantry (for example, a large crane).

[0141] (B) Winch rope and winch drum In the above embodiment, the first winch rope R1 is the opening / closing rope, the second winch rope R2 is the support rope, the first winch drum DR1 is the opening / closing drum, and the second winch drum DR2 is the support drum, but these may be configured in reverse. That is, the first winch rope R1 may be the support rope, the second winch rope R2 may be the opening / closing rope, the first winch drum DR1 may be the support drum, and the second winch drum may be the opening / closing drum.

[0142] (C) The open / closed state determination unit may be configured to determine the open / closed state of the bucket device 10 based on the relative position of the lower ends of the pair of buckets 13, 13. In this case, the bucket control device is equipped with a detection sensor that detects the relative position of the lower ends of the pair of buckets 13, 13. The detection sensor may be, for example, a sensor that detects whether the lower ends of the pair of buckets 13, 13 are in contact with each other, or a sensor that detects the distance between the lower ends of the pair of buckets 13, 13.

[0143] (D) Operating device The operating device according to the present disclosure may be appropriately selected depending on the types of the first and second winches and their drive devices. For example, the operating device bodies 51B, 53B, 52B, and 54B of the first winch operating device 51, the second winch operating device 53, the first brake operating device 52, and the second brake operating device 54 shown in Figures 2 and 3 may each be replaced with a remote control valve that outputs a pilot pressure according to the operation. In this case, proportional valves 61A and 61B are respectively interposed between the remote control valve of the first winch operating device 51 and a pair of pilot ports of the first control valve, and proportional valves 63A and 63B are respectively interposed between the remote control valve of the second winch operating device 53 and a pair of pilot ports of the second control valve 33. In addition, a proportional valve 62 is interposed between the remote control valve of the first brake operating device 52 and the first clutch brake 40A, and a proportional valve 64 is interposed between the remote control valve of the second brake operating device 54 and the second clutch brake 40B.

[0144] (E) About winches The first and second winches according to the present disclosure may be, for example, electric winches. In this case, the hydraulic circuit shown in Fig. 3 can be replaced with an electric circuit (for example, a circuit including an inverter) that drives the electric winch. [Explanation of symbols]

[0145] 10: Bucket device 11: Upper member of bucket device (an example of the main body) 13: Bucket 40: Clutch brake mechanism 51: First winch operating device (an example of an opening / closing winch operating device) 52: First brake operating device (an example of an opening / closing side brake operating device) 53: Second winch operating device (an example of a support winch operating device) 54: Second brake operating device (an example of a support side brake operating device) 70: Controller 71: Open / close state determination unit 72: Brake force adjustment unit 73: Drum operation control section 81: First rotation sensor (an example of an opening / closing side detector) 82: Second rotation sensor (an example of a support side detector) 90: Non-synchronized control mode switch (an example of a control mode setting section) 91: Bucket assist mode switch (an example of a control mode setting unit) 100: Crane (an example of construction machinery) DR1: First winch drum (an example of an opening / closing drum) DR2: Second winch drum (an example of a support drum) H: Deviation (relative difference in feed amount) Lm: First extension amount (opening / closing side extension amount) La: Second extension amount (support side extension amount) R1: First winch rope (an example of an opening and closing rope) R2: Second winch rope (an example of a support rope) ΔL: Relative difference in feed amount ΔLr: Target relative difference in feed amount

Claims

1. A bucket control device mounted on a construction machine, the bucket control device including a bucket device including a main body and a pair of buckets attached to the main body in an openable and closable manner, a support drum which is a winch drum connected to the main body and which reels out and takes up a support rope that supports the main body, and an opening / closing drum which is a winch drum which reels out and takes up an opening / closing rope for opening and closing the pair of buckets, a support-side winch operating device that is provided with a support-side winding operation, which is an operation for rotating the support drum so as to wind up the support rope, and a support-side unwinding operation, which is an operation for rotating the support drum so as to unwind the support rope; an opening / closing side winch operating device that is provided with an opening / closing side winding operation, which is an operation for rotating the opening / closing drum so as to wind up the opening / closing rope, and an opening / closing side payout operation, which is an operation for rotating the opening / closing drum so as to pay out the opening / closing rope; a support side detector for detecting a support side payout amount, which is the payout amount of the support rope; an opening / closing side detector for detecting an opening / closing side payout amount, which is the payout amount of the opening / closing rope; a control mode setting unit that can set a control mode to a synchronized control mode in which the winding of the support rope and the winding of the opening and closing rope can be performed based on a specific winding operation that is either the support side winding operation or the opening and closing side winding operation; a controller; The controller an open / closed state determination unit that determines whether the pair of buckets are in a closed state; a drum operation control unit that, when the control mode is set to the synchronized control mode, the specific winding operation is being performed, and the open / closed state determination unit determines that the bucket device is in the closed state, sets a payout relative difference target value that is a target value for the difference between the opening / closing side payout amount and the support side payout amount, based on a support side slack amount setting value that is a slack amount of the support rope, the set value being set to prevent the pair of buckets from opening, calculates a payout relative difference that is the difference between the opening / closing side payout amount and the support side payout amount, calculates a deviation between the payout relative difference target value and the payout relative difference, and outputs a command signal such that the deviation approaches zero, thereby controlling operation of the support drum and the open / close drum.

2. The bucket control device according to claim 1, In the synchronized control mode, the payout of the support rope and the payout of the opening and closing rope can be performed based on a specific payout operation, which is either the support side payout operation or the opening and closing side payout operation, When the control mode is set to the synchronized control mode, the specific extension operation is performed, and the opening / closing state determination unit determines that the bucket device is in the closed state, the drum operation control unit sets the target value of relative difference in extension amount based on the set value, calculates the relative difference in extension amount, calculates the deviation between the target value of relative difference in extension amount and the relative difference in extension amount, and outputs a command signal to control the operations of the support drum and the opening / closing drum so that the deviation approaches zero, thereby lowering the bucket device while maintaining the closed state of the bucket device.

3. The bucket control device according to claim 1 or 2, the open / closed state determination unit is capable of determining whether the pair of buckets are in an open state, When the control mode is set to the synchronized control mode, the specific winding operation is being performed, and the open / closed state determination unit determines that the bucket device is in the open state, the drum operation control unit sets a second target value of relative difference in payout amount that is a target value for maintaining the pair of buckets at a predetermined opening degree, calculates the relative difference in payout amount, calculates a second deviation that is the deviation between the second target value of relative difference in payout amount and the relative difference in payout amount, and outputs a command signal such that the second deviation approaches zero, thereby controlling the operations of the support drum and the open / close drum, thereby raising the bucket device while maintaining the open state of the bucket device.

4. The bucket control device according to claim 1, In the synchronized control mode, the payout of the support rope and the payout of the opening and closing rope can be performed based on a specific payout operation, which is either the support side payout operation or the opening and closing side payout operation, the open / closed state determination unit is capable of determining whether the pair of buckets are in an open state, When the control mode is set to the synchronized control mode, the specific extension operation is performed, and the open / close state determination unit determines that the bucket device is in the open state, the drum operation control unit sets a second target value of relative difference in extension amount that is a target value for maintaining the pair of buckets at a predetermined opening degree, calculates the relative difference in extension amount, calculates a second deviation that is the deviation between the second target value of relative difference in extension amount and the relative difference in extension amount, and outputs a command signal such that the second deviation approaches zero, thereby controlling the operations of the support drum and the open / close drum, thereby lowering the bucket device while maintaining the open state of the bucket device.

5. The bucket control device according to any one of claims 1 to 4, the control mode setting unit is configured to be able to set the control mode to one of a plurality of modes including the synchronized control mode and a non-synchronized control mode; The bucket control device, wherein the asynchronous control mode is a control mode that allows the bucket device to perform an operation including changing an open / closed state of the pair of buckets based on a specific operation that is set in advance.

6. The bucket control device according to any one of claims 1 to 5, The open / close state determination unit determines whether the pair of buckets are in a closed state based on a difference between the support side extension amount and the open / close side extension amount.

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