Bucket control device, construction machine, and bucket control method

Abstract

This bucket control device is for a construction machine (100) comprising: a first winch drum (DR1) that pays out and winds up a first winch rope (R1); a second winch drum (DR2) that pays out and winds up a second winch rope (R2); and a bucket device (10) that is connected to the first winch rope (R1) and the second winch rope (R2) and is capable of opening / closing and raising / lowering in response to the rotation of the first winch drum (DR1) and the rotation of the second winch drum (DR2). The bucket control device comprises a controller (70) that determines the open / closed state of the bucket device (10) and notifies an operator of the determined open / closed state of the bucket device (10).

Description

Bucket control device, construction machine, and bucket control method

[0001] The present disclosure relates to a bucket control device that opens, closes, raises, and lowers a bucket device mounted on a construction machine such as a crane.

[0002] Patent Documents 1 and 2 describe a first winch drum that pays out and winds up a first winch rope, a second winch drum that pays out and winds up a second winch rope, and a bucket device that is connected to the first winch rope and the second winch rope and can be opened, closed, raised, and lowered according to the rotation of the first winch drum and the rotation of the second winch drum. A bucket control device mounted on a construction machine is described.

[0003] By the way, at a work site where it is difficult to visually check the state of the bucket device, it is difficult to grasp the current state of the bucket device, so there is room for improvement.

[0004] Japanese Patent Application Laid-Open No. 2023-23811 Japanese Patent Application Laid-Open No. 2023-23812

[0005] The present disclosure has been made to solve the above problems, and an object thereof is to provide a bucket control device that can grasp the state of a bucket device even at a work site where the bucket device is difficult to visually check.

[0006] A bucket control device according to a first aspect includes a first winch drum that pays out and winds up a first winch rope, a second winch drum that pays out and winds up a second winch rope, and the first winch rope and the second winch rope. A bucket control device for a construction machine, comprising a bucket device that is connected to and can be opened, closed, raised, and lowered according to the rotation of the first winch drum and the rotation of the second winch drum, and a controller that determines the open / closed state of the bucket device and notifies the operator of the determined open / closed state of the bucket device.

[0007] Figure 1 is a side view showing a crane equipped with a bucket control device according to the first, second, third, or fourth embodiment of this disclosure. Figure 2 is a block diagram illustrating the schematic functional configuration of the crane according to the first, second, third, or fourth embodiment. Figure 3 is a diagram showing the hydraulic circuit provided by the crane according to the first, second, third, or fourth embodiment. Figure 4 is a diagram illustrating the opening and closing operation of the bucket device provided by the crane according to the first, second, third, or fourth embodiment. Figure 5 is a block diagram illustrating the main part of the control function of the controller of the crane according to the first or second embodiment. Figure 6 is a diagram showing the state of the bucket device in the fully open state and the fully closed state in the crane according to the first or second embodiment. Figure 7 is a diagram showing an example of the change in the degree of opening and closing of the bucket device during operation of the crane according to the first or second embodiment. Figure 8 is an example of a screen showing the degree of opening and closing of the bucket device displayed on a monitor in the crane according to the first or second embodiment. Figure 9 is an example of an image displayed on the monitor when setting the fully open and fully closed states of the bucket device in the crane according to the first or second embodiment. Figure 10 is a diagram showing the state in which the bucket device is at its maximum lifting height and the state in which the bucket device is at its minimum lifting height in the crane according to the first or second embodiment. Figure 11 is an example of an image displayed on the monitor when moving the bucket device to its maximum and minimum lifting heights in the crane according to the first or second embodiment. Figure 12 is a flowchart of the control operation performed when determining the rope responsible for opening and closing the bucket device in the crane according to the first or second embodiment. Figure 13 is an example of an image displayed on the monitor when confirming whether the determination result of the rope responsible for opening and closing is correct in the crane according to the first or second embodiment.Figure 14 is a flowchart illustrating the controller's control operation performed in the crane according to the first or second embodiment when setting the maximum relative difference and minimum relative difference, and when determining the rope responsible for opening and closing the bucket device. Figure 15 is a block diagram illustrating the schematic functional configuration of the bucket control device of the crane according to the third or fourth embodiment. Figure 16 is a diagram showing the state of the bucket device in the fully open state and the fully closed state in the crane according to the third or fourth embodiment. Figure 17 is a diagram showing an example of the change in the degree of opening and closing of the bucket device during operation of the crane according to the third or fourth embodiment. Figure 18 is a diagram showing the state of the bucket device in the over-open state and the over-closed state in the crane according to the third or fourth embodiment. Figure 19 is a flowchart illustrating the controller's control operation to suppress the over-open and over-closed states of the bucket device in the crane according to the third or fourth embodiment. Figure 20 is an example of an image displayed on the monitor when setting the fully open state and the fully closed state of the bucket device in the crane according to the third or fourth embodiment. Figure 21 shows the state in which the bucket device is at its maximum lifting height and the state in which the bucket device is at its minimum lifting height in the crane according to the third or fourth embodiment. Figure 22 is an example of an image displayed on the monitor when moving the bucket device to the maximum and minimum lifting heights in the crane according to the third or fourth embodiment. Figure 23 is a flowchart of the control operation performed when determining the rope responsible for opening and closing the bucket device in the crane according to the third or fourth embodiment. Figure 24 is an example of an image displayed on the monitor when confirming whether the determination result for the rope responsible for opening and closing is correct in the crane according to the third or fourth embodiment.

[0008] Preferred embodiments of this disclosure will be described with reference to the drawings.

[0009] This disclosure includes a first technology and a second technology. The first technology mainly includes the first and second embodiments described below. The second technology mainly includes the third and fourth embodiments described below. Figures 1 to 4 show the technical content common to the first, second, third, and fourth embodiments. Figures 5 to 14 show the technical content relating to the first and second embodiments. Figures 15 to 24 show the technical content relating to the third and fourth embodiments.

[0010] [Overview of the Crane] First, an overview of the crane 100 common to the first, second, third, and fourth embodiments will be described with reference to Figures 1 to 4.

[0011] Figure 1 shows a crane 100, which is a construction machine according to the first, second, third, or fourth embodiment. This crane 100 comprises a lower body 101, an upper slewing body 102 that is rotatably supported on the lower body 101, a luffing member 104 that is luffably supported on the upper slewing body 102, a first point sheave 105 and a second point sheave 106 attached to the tip of the luffing member 104, a plurality of winches arranged on the lower body 101 or the upper slewing body 102, a bucket device 10, and a bucket control device.

[0012] The lower body 101 is equipped with a travel device, such as a crawler travel device, and is configured to be self-propelled. However, the lower body may be composed of a structure such as a support base that rotatably supports the upper slewing body 102 and is not self-propelled. The upper slewing body 102 comprises a slewing frame 103 rotatably attached to the lower body 101, a cabin supported at the front of the slewing frame 103, and a counterweight supported at the rear of the slewing frame 103. The plurality of winches include a first winch WC1, a second winch WC2, and a luffing winch WC3.

[0013] The luffing member 104 is composed of a boom supported on a slewing frame 103 so as to be able to be raised and lowered. However, the luffing member may also include a boom and a jib rotatably supported at the tip of the boom. A gantry 107 is erected on the slewing frame 103. A lower spreader 110 is positioned at the upper end of the gantry 107. One end of a guy line 108 is connected to the tip of the luffing 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 spaced apart from each other. A luffing rope 111 is wrapped around the lower spreader 110 and the upper spreader 109. The luffing winch WC3 is positioned on the slewing frame 103 and has a winch drum DR3 around which the luffing rope 111 is wound. The luffing winch WC3 reduces or increases the distance between the upper spreader 109 and the lower spreader 110 by winding in or unwinding the luffing rope 111. The luffing member 104 is raised or lowered in accordance with the reduction or increase in this distance.

[0014] Figure 2 is a block diagram showing the functional configuration of the bucket control device. Figure 3 is a diagram showing the hydraulic circuit provided by the crane 100.

[0015] The first winch WC1 and the second winch WC2 are driven to open, close, and raise the bucket device 10. Specifically, as shown in Figures 1 to 3, the first winch WC1 has a first winch drum DR1 around which the 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 reduction gear 47. Similarly, the second winch WC2 has a second winch drum DR2 around which the 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 reduction gear 47. The first winch rope R1 is an opening and closing rope for opening and closing the bucket device 10, and the second winch rope R2 is a support rope for supporting the bucket device 10. The first winch drum DR1 is an opening / closing drum that pays out and retracts the first winch rope R1 (opening / closing rope), and the second winch drum DR2 is a support drum that pays out and retracts the second winch rope R2 (support rope).

[0016] The first winch drum DR1 is supported by a support member (not shown) so as to be rotatable around a horizontal axis, enabling it to pay out and retract the first winch rope R1. The second winch drum DR2 is supported by a support member (not shown) so as to be rotatable around a horizontal axis, enabling it to pay out and retract the second winch rope R2.

[0017] The first point sheave 105 and the second point sheave 106 are arranged side by side and attached to the tip of the luffing 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 and R2 are connected to the bucket device 10.

[0018] The bucket device 10 is a working device known as a clamshell bucket. The bucket device 10 is connected to the first winch rope R1 and the second winch rope R2, and can be opened and closed and raised and lowered in accordance with the rotation of the first winch drum DR1 and the second winch drum DR2. The right diagram of Figure 4 shows the bucket device 10 in the open state, and the left diagram of Figure 4 shows the bucket device 10 in the closed state. The bucket device 10 comprises an upper member 11, a lower member 16 positioned 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.

[0019] The pair of link members 12, 12 are arranged horizontally, spaced apart from each other. The upper ends of the pair of link members 12, 12 are connected to the upper member 11 so as to be rotatable around a horizontal axis. One lower end of the pair of link members 12, 12 is connected to one of the pair of buckets 13, 13 so as to be rotatable around a horizontal axis, and the other lower end 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 around a horizontal axis.

[0020] The lower sheave 14 is supported by the lower member 16 so as to be rotatable around a horizontal axis. Each of the pair of buckets 13 has a supported portion that is supported by the lower member 16 so as to be rotatable around a horizontal axis. The upper sheave 15 is supported by the upper member 11 so as to be rotatable around a horizontal axis.

[0021] The pair of buckets 13, 13 have a storage space capable of accommodating materials to be transported, such as soil and sand. The pair of buckets 13, 13 can rotate around the supported part, allowing them to be displaced between a state where the lower ends of the buckets 13, 13 are adjacent to each other (the closed state) and a state where the lower ends of the buckets 13, 13 are separated horizontally (the open state). 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 materials to be transported contained in the storage space. By switching from the closed state to the open state, the pair of buckets 13, 13 can discharge the materials to be transported from the storage space to the outside of the buckets 13, 13.

[0022] The first winch rope R1 is wrapped around the lower sheave 14 and the upper sheave 15, and the end of the first winch rope R1 is fixed to either the upper member 11 or the lower member 16. The end of the second winch rope R2 is fixed to the upper member 11.

[0023] The first and second winch motors 34 and 35 are variable displacement hydraulic motors connected to the hydraulic pump 31. The first winch motor 34 operates by receiving hydraulic fluid discharged from the hydraulic pump 31 to rotate the first winch drum DR1 in either the forward or reverse direction, i.e., the unwinding direction or the winding direction. Similarly, the second winch motor 35 operates by receiving hydraulic fluid discharged from the hydraulic pump 31 to rotate the second winch drum DR2 in either the forward or reverse direction, i.e., the unwinding direction or the winding direction. This enables the opening and closing and raising and lowering of the bucket device 10 through the cooperation of the first winch WC1 and the second winch WC2. The hydraulic pump 31 is driven by a power source such as an engine (not shown).

[0024] The reduction gear 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 reduction gear 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. These reduction gears 47 each have, for example, a planetary gear mechanism.

[0025] The first clutch brake 40A can switch 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 unwound from the first winch drum DR1 by the weight of the bucket device 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.

[0026] Similarly, the second clutch brake 40B can switch 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 unfurled from the second winch drum DR2 by the weight of the bucket device 10. The second clutch brake 40B can adjust the degree of connection between the second winch motor 35 and the second winch drum DR2 between the connected state and the free state.

[0027] The aforementioned connection state is one in which the first and second winch ropes R1 and R2 can be unwound and wound up by the driving force of the first and second winch motors 34 and 35. That is, when the first and second winch motors 34 and 35 are driven in the aforementioned connection state, the driving force of the first and second winch motors 34 and 35 is transmitted to the first and second winch drums DR1 and DR2, respectively, via the reduction gears 47 and 47. When the first and second winch drums DR1 and DR2 rotate, the first and second winch ropes R1 and R2 are unwound or wound up.

[0028] The free state is a state in which the first and second winch ropes R1 and R2 can be unfurled from the first and second winch drums DR1 and DR2 by the tension of the first and second winch ropes R1 and R2, that is, a state in which the bucket device 10 can free fall. In other words, the free state is a state in which the first and second winch ropes R1 and R2 can be unfurled from the first and second winch drums DR1 and DR2 without rotating the first and second winch motors 34 and 35 in the unfurling direction of the first and second winch ropes R1 and R2.

[0029] Furthermore, the first clutch brake 40A can apply a first braking force to the first winch drum DR1, that is, it can brake the first winch drum DR1. Similarly, the second clutch brake 40B can apply a second braking force to the second winch drum DR2, that is, it can brake the second winch drum DR2.

[0030] When the first braking force against the rotation of the first winch drum DR1 exceeds a predetermined magnitude, the first winch drum DR1 is braked, making it impossible to pay out the first winch rope R1 from the first winch drum DR1. Similarly, when the second braking force against the rotation of the second winch drum DR2 exceeds a predetermined magnitude, the second winch drum DR2 is braked, making it impossible to pay 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 are sufficient to maintain the bucket device 10 in a stationary state without free-falling, and to stop the bucket device 10 if it is free-falling.

[0031] In the first, second, third, and fourth embodiments, the first clutch brake 40A and the second clutch brake 40B are each so-called wet brakes and include a piston 42 driven by hydraulic pressure supplied from a pilot hydraulic power 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 fluid.

[0032] The multiple brake discs 41 can be switched between a state in which the multiple brake discs 41 are in contact with each other and a state in which the multiple brake discs 41 are separated from each other by the operation of the piston 42. When the multiple brake discs 41 are separated from each other, the first clutch brake 40A and the second clutch brake 40B are in the free state, which allows the bucket device 10 to descend (free fall) by its own weight. The first clutch brake 40A and the second clutch brake 40B are in the connected state when the multiple brake discs 41 come into contact with each other.

[0033] More specifically, each of the first clutch brake 40A and the second clutch brake 40B is equipped with a spring 46, and each of the first clutch brake 40A and the second clutch brake 40B has a pair of oil chambers 43 and 44 formed therein, and the piston 42 has a flange 45 that separates the pair of oil chambers 43 and 44. When the hydraulic pressure applied to the pair of oil chambers 43 and 44 from the pilot hydraulic power source P is the same, the spring 46 biases the piston 42 so that the multiple brake discs 41 come into contact with each other. When the hydraulic pressure applied to one oil chamber 44 from the pilot hydraulic power source P becomes greater than or equal to a predetermined amount than the hydraulic pressure applied to the other oil chamber 43, the multiple brake discs 41 move apart from each other.

[0034] 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 comprises a first control valve 32, a second control valve 33, a first payout proportional valve 61A, a first winding proportional valve 61B, a second payout proportional valve 63A, a second winding proportional valve 63B, a first brake proportional valve 62, a second brake proportional valve 64, a plurality of operating devices, and a controller 70. In the first, second, third, and fourth embodiments, each of the proportional valves 61A, 61B, 62, 63A, 63B, and 64 is an electromagnetic proportional pressure reducing valve capable of linearly adjusting the output pressure.

[0035] 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 and 33 is composed of a hydraulic pilot switching valve having a pair of pilot ports.

[0036] The pair of pilot ports are a pay-out pilot port and a retraction pilot port. When no pilot pressure is applied to either pilot port, the first and second control valves 32 and 33 are held in a neutral position, disconnecting the winch motor corresponding to the control valve (hereinafter referred to as the "corresponding winch motor") among the first and second winch motors 34 and 35 from the hydraulic pump 31.

[0037] Each of the first and second control valves 32 and 33 opens to form an oil passage for rotating the corresponding winch motor in the unwinding direction when pilot pressure is applied to the unwinding pilot port, that is, an oil passage for supplying hydraulic fluid from the hydraulic pump 31 to the corresponding winch motor in the unwinding direction. Each of the first and second control valves 32 and 33 opens to form an oil passage for rotating the corresponding winch motor in the winding direction when pilot pressure is applied to the winding pilot port, that is, an oil passage for supplying hydraulic fluid 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 and 33 increases with increasing pilot pressure to allow hydraulic fluid to flow at a flow rate corresponding to the pilot pressure input to the control valve.

[0038] The first dispensing proportional valve 61A is interposed between a pilot hydraulic power source (not shown) and the dispensing pilot port of the first control valve 32. When a first dispensing command, which is an electrical signal, is input to the proportional valve 61A from the controller 70, the valve opens to allow a pilot pressure proportional to the first dispensing command to be input to the dispensing pilot port. The first retracting proportional valve 61B is interposed between the pilot hydraulic power source and the retracting pilot port of the first control valve 32. When a first retracting command, which is an electrical signal, is input to the proportional valve 61B from the controller 70, the valve opens to allow a pilot pressure proportional to the first retracting command to be input to the retracting pilot port.

[0039] Similarly, the second dispensing proportional valve 63A is interposed between a pilot hydraulic power source (not shown) and the dispensing pilot port of the second control valve 33. When a second dispensing command, which is an electrical signal, is input to the proportional valve 63A from the controller 70, the valve opens to allow a pilot pressure proportional to the second dispensing command to be input to the dispensing pilot port. The second retracting proportional valve 63B is interposed between the pilot hydraulic power source and the retracting pilot port of the second control valve 33. When a second retracting command, which is an electrical signal, is input to the proportional valve 63B from the controller 70, the valve opens to allow a pilot pressure proportional to the second retracting command to be input to the retracting pilot port.

[0040] As described above, the first control valve 32, the first dispensing proportional valve 61A, and the first retracting proportional valve 61B constitute a first speed controller that changes the flow rate and direction of the hydraulic fluid 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 controller changes the speed at which the first winch motor 34 rotates the first winch drum DR1. Similarly, the second control valve 33, the second dispensing proportional valve 63A, and the second retracting proportional valve 63B constitute a second speed controller that changes the flow rate and direction of the hydraulic fluid 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 controller changes the speed at which the second winch motor 35 rotates the second winch drum DR2.

[0041] Even when a first unwinding operation is applied to the first winch operating lever 51A of the first winch operating device 51 (described later), if the controller 70 inputs a command to the first unwinding proportional valve 61A to set the pilot pressure input to the unwinding pilot port of the first control valve 32 to a predetermined value or less (for example, zero), the spool of the first control valve 32 moves to the neutral position. As a result, the supply of hydraulic fluid to the first winch motor 34 is stopped, and the rotation of the first winch motor 34 stops, thereby stopping the rotation of the first winch drum DR1. Note that when stopping the rotation of the first winch drum DR1 in the unwinding direction, the controller 70 may input the command to the first unwinding proportional valve 61A and also input a command to the first winding proportional valve 61B to set the pilot pressure input to the winding pilot port of the first control valve 32 to a predetermined value or less (for example, zero).

[0042] Even when a first winding operation is applied to the first winch operating lever 51A of the first winch operating device 51, if the controller 70 inputs a command to the first winding proportional valve 61B to set the pilot pressure input to the winding pilot port of the first control valve 32 to a predetermined value or less (for example, zero), the spool of the first control valve 32 moves to the neutral position. As a result, the supply of hydraulic fluid to the first winch motor 34 is stopped, the rotation of the first winch motor 34 is stopped, and the rotation of the first winch drum DR1 is stopped. Note that when stopping the rotation of the first winch drum DR1 in the winding direction, the controller 70 may input the command to the first winding proportional valve 61B and also input a command to the first unwinding proportional valve 61A to set the pilot pressure input to the unwinding pilot port of the first control valve 32 to a predetermined value or less (for example, zero).

[0043] As described above, the first control valve 32 also functions as a first stopping device for stopping the rotation of the first winch drum DR1. Further, each of the first payout proportional valve 61A and the first take-up proportional valve 61B is an example of a first proportional valve capable of stopping the rotation of the first winch drum DR1.

[0044] Even when a second payout operation is applied to the second winch operation lever 53A of the second winch operation device 53 described later, when the controller 70 inputs a command to the second payout proportional valve 63A to make the pilot pressure input to the payout pilot port of the second control valve 33 below a predetermined value (for example, zero), the spool of the second control valve 33 moves to the neutral position. As a result, the supply of hydraulic oil to the second winch motor 35 is stopped, and the rotation of the second winch motor 35 is stopped, so that the rotation of the second winch drum DR2 is stopped. When stopping the rotation of the second winch drum DR2 in the payout direction, the controller 70 may input the command to the second payout proportional valve 63A and also input a command to the second take-up proportional valve 63B to make the pilot pressure input to the take-up pilot port of the second control valve 33 below a predetermined value (for example, zero).

[0045] Even when the second winch operating lever 53A of the second winch operating device 53 is assigned a first winding operation, if the controller 70 inputs a command to the second winding proportional valve 63B to set the pilot pressure input to the winding pilot port of the second control valve 33 to a predetermined value or less (for example, zero), the spool of the second control valve 33 moves to the neutral position. As a result, the supply of hydraulic fluid to the second winch motor 35 is stopped, the rotation of the second winch motor 35 is stopped, and the rotation of the second winch drum DR2 is stopped. Note that when stopping the rotation of the second winch drum DR2 in the winding direction, the controller 70 may input the command to the second winding proportional valve 63B and also input a command to the second unwinding proportional valve 63A to set the pilot pressure input to the unwinding pilot port of the second control valve 33 to a predetermined value or less (for example, zero).

[0046] As described above, the second control valve 33 also functions as a second stop device that stops the rotation of the second winch drum DR2. Furthermore, the second pay-out proportional valve 63A and the second rewind proportional valve 63B are examples of second proportional valves capable of stopping the rotation of the second winch drum DR2.

[0047] The first brake proportional valve 62 is interposed between the pilot hydraulic power source P and the first clutch brake 40A. When the controller 70 inputs a first brake command, which is an electrical signal, to the proportional valve 62, the valve opens to allow hydraulic pressure (first pilot pressure) proportional to the first brake command to be input to the oil chamber 43 of the first clutch brake 40A. As a result, the first brake proportional valve 62 can switch the state of the first clutch brake 40A between the free state and the connected state.

[0048] Similarly, the proportional valve 64 for the second brake is interposed between the pilot hydraulic pressure source P and the second clutch brake 40B, and as a second brake command, which is an electric signal, is input from the controller 70 to the proportional valve 64, the proportional valve 64 opens to allow hydraulic pressure (second pilot pressure) proportional to the second brake command to be input to the oil chamber 43 of the second clutch brake 40B. Thereby, the proportional valve 64 for the second brake can switch the state of the second clutch brake 40B between the free state and the connected state.

[0049] The plurality of operating devices includes 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.

[0050] In the following description, the first winch rope R1 may be referred to as the main winding rope, the second winch rope R2 may be referred to as the auxiliary winding rope, the first winch drum DR1 may be referred to as the main winding drum, and the second winch drum DR2 may be referred to as the auxiliary winding drum. Also, the first winch operating lever 51A may be referred to as the main winding lever, and the second winch operating lever 53A may be referred to as the auxiliary winding lever. Also, the first brake operating pedal 52A may be referred to as the main winding pedal, and the second brake operating pedal 54A may be referred to as the auxiliary winding pedal. In the crane 100, instead of the bucket device 10, a main winding hook (not shown) may be attached to the tip of the first winch rope R1 (main winding rope), and an auxiliary winding hook (not shown) may be attached to the tip of the second winch rope R2 (auxiliary winding rope). "Main winding" is mainly used for heavy load lifting for lifting heavy loads, and "auxiliary winding" is mainly used for auxiliary lifting of light loads.

[0051] The first winch operating lever 51A is an operating member to which a first rotational operation is performed by the operator to specify the drive speed (rotational speed) of the first winch drum DR1. Specifically, the first winch operating lever 51A is provided with either a first unwinding operation to rotate the first winch drum DR1 in the unwinding direction to unwind the first winch rope R1, or a first winding operation to rotate the first winch drum DR1 in the winding direction to wind up the first winch rope R1, as the first rotational operation.

[0052] The first winch operating device body 51B inputs a command signal to the controller 70 to command a rotational speed corresponding to the amount of operation (lever operation amount) of the first rotation operation (first payout operation or first winding operation) applied to the first winch operating lever 51A.

[0053] Similarly, the second winch operating lever 53A is an operating member to which a second rotational operation is performed by the operator to specify the drive speed (rotational speed) of the second winch drum DR2. Specifically, the second winch operating lever 53A is provided with either a second payout operation to rotate the second winch drum DR2 in the payout direction to pay out the second winch rope R2, or a second winding operation to rotate the second winch drum DR2 in the winding direction to wind up the second winch rope R2, as the second rotational operation.

[0054] The second winch operating device body 53B inputs a command signal to the controller 70 to command a rotational speed corresponding to the amount of operation (lever operation amount) of the second rotation operation (second payout operation or second winding operation) applied to the second winch operating lever 53A.

[0055] The first brake operation pedal 52A is an operating member to which the operator performs a pedal operation (an example of a first brake operation) to specify the first brake force applied to the first winch drum DR1. The first brake operation device body 52B inputs a command signal to the controller 70 to command a brake force of a magnitude corresponding to the amount of the first pedal operation (pedal operation amount) applied to the first brake operation pedal 52A.

[0056] The second brake operation pedal 54A is an operating member to which the operator performs a pedal operation (an example of a second brake operation) to specify the second brake force applied to the second winch drum DR2. The second brake operation device body 54B inputs a command signal to the controller 70 to command a brake force of a magnitude corresponding to the amount of the second pedal operation (pedal operation amount) applied to the second brake operation pedal 54A.

[0057] The bucket control device further includes, as shown in Figure 2, a first rotation sensor 81, a second rotation sensor 82, and a control mode setting unit. In the first, second, third, and fourth embodiments, the control mode setting unit includes a non-synchronized control mode switch 90 (one-sided on / off switch 90) and a bucket assist mode switch 91. The first rotation sensor 81 is an example of the first detector of this disclosure, and the second rotation sensor 82 is an example of the second detector of this disclosure.

[0058] The first rotation sensor 81 generates a first detection signal for a first rotation amount nm, which is the amount of rotation of the first winch drum DR1, and inputs it to the controller 70. The second rotation sensor 82 generates a second detection signal for a second rotation amount na, which is the amount of rotation of the second winch drum DR2, and inputs it to the controller 70. The first rotation amount nm and the second rotation amount na are rotation amounts from a set reference value, respectively. Note that the first rotation sensor 81 may be a sensor that generates a detection signal for the amount of rotation of the first point sheave 105 instead of the amount of rotation of the first winch drum DR1, and the second rotation sensor 82 may be a sensor that generates a detection signal for the amount of rotation of the second point sheave 106 instead of the amount of rotation of the second winch drum DR2.

[0059] In the first, second, third, and fourth embodiments, the controller 70 sets the control mode of the controller 70 to one of a predetermined number of control modes based on a command signal input from the control mode setting unit. In the first, second, third, and fourth embodiments, the number of control modes includes 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 number of control modes may further include other control modes.

[0060] The bucket assist mode is a control mode in which the controller 70 performs assist control to enable the operator to perform at least one of the following operations, opening / closing and raising / lowering, of the bucket device 10 with simple operation. The non-assist mode is a control mode in which the above-mentioned assist control is not performed. Assist control includes main auxiliary synchronization control and free synchronization control.

[0061] The above-described main auxiliary synchronization control is a control that synchronizes the operation of the first winch drum DR1 and the operation of the second winch drum DR2. In the main auxiliary synchronization control, the controller 70 controls the operation of the first winch drum DR1 and the operation of the second winch drum DR2 based on the operation given to the first winch operating device 51.

[0062] For example, in main-auxiliary synchronization control, when an unwinding operation is applied to the first winch operating device 51, the controller 70 performs the following opening-down control or closing-down control. In the above opening-down control, the controller 70 controls the operation of the first winch drum DR1 and the second winch drum DR2 so that the bucket device 10 descends while maintaining the open state of the bucket device 10. In the above closing-down control, the controller 70 controls the operation of the first winch drum DR1 and the second winch drum DR2 so that the bucket device 10 descends while maintaining the closed state of the bucket device 10. Furthermore, in main-auxiliary synchronization control, when a winding operation is applied to the first winch operating device 51, the controller 70 performs the following opening-up control or closing-up control. In the above opening-up control, the controller 70 controls the operation of the first winch drum DR1 and the second winch drum DR2 so that the bucket device 10 rises while maintaining the open state of the bucket device 10. In the above closing control, the controller 70 controls the operation of the first winch drum DR1 and the second winch drum DR2 so that the bucket device 10 rises while maintaining the closed state of the bucket device 10.

[0063] The above-described free synchronization control is a control that synchronizes the first braking force of the first winch drum DR1 and the second braking force of the second winch drum DR2. In free synchronization control, the controller 70 controls the first braking force of the first winch drum DR1 and the second braking force of the second winch drum DR2 based on the amount of operation of the first brake operating device 52.

[0064] For example, in free-synchronized control, if a braking operation is applied to the first brake operating device 52 that reduces the first braking force, the controller 70 performs the following opening-down control or closing-down control. In the opening-down control, the controller 70 adjusts the first and second braking forces so that the bucket device 10 descends by its own weight while maintaining the open state of the bucket device 10. In the closing-down control, the controller 70 adjusts the first and second braking forces so that the bucket device 10 descends by its own weight while maintaining the closed state of the bucket device 10.

[0065] In the first, second, third, and fourth embodiments, the control mode is set to bucket assist mode when the bucket assist mode switch 91 is ON, and the control mode is set to non-assist mode when the bucket assist mode switch 91 is OFF. In bucket assist mode, the control mode is set to non-synchronized control mode when the non-synchronized control mode switch 90 is ON, and the control mode is set to synchronized control mode when the non-synchronized control mode switch 90 is OFF.

[0066] In the first, second, third, and fourth embodiments, synchronization control such as main and auxiliary synchronization control and free synchronization control is performed in the synchronization control mode. The operations of the bucket device 10 in the synchronization control mode include the "closed up" operation, which raises the bucket device 10 in the closed state; the "opened up" operation, which raises the bucket device 10 in the open state; the "opened down" operation, which lowers the bucket device 10 in the open state; and the "closed down" operation, which lowers the bucket device 10 in the closed state. In the non-synchronized control mode, the above-mentioned main and auxiliary synchronization control and free synchronization control are not performed. That is, in the non-synchronized control mode, the raising and lowering and opening and closing of the bucket device 10 are performed by the operator's manual operation.

[0067] [First Embodiment] Next, the features of the first embodiment will be described in detail. Figure 5 is a block diagram illustrating the main part of the control function of the controller 70 according to the first embodiment. The controller 70 controls the driving of the first winch WC1 and the second winch WC2 to open, close and raise and lower the bucket device 10. The controller 70 has a computer including a central processing unit (a processing unit such as a CPU) not shown in the figure, and a storage unit 78 consisting of ROM and RAM, and executes various processes including opening, closing and raising and lowering the bucket device 10. The controller 70 has an opening / closing state determination unit 71, a screen display control unit 72, a brake force adjustment unit 75, a drum operation control unit 76, a condition setting unit 77, a storage unit 78, and an opening / closing rope determination unit 79, and these functions are executed by the processing unit executing a control program stored in the storage unit 78.

[0068] The controller 70 receives various command signals, including the first rotation amount nm of the first winch drum DR1 detected by the first rotation sensor 81, the second rotation amount na of the second winch drum DR2 detected by the second rotation sensor 82, an ON command signal output from the non-synchronized control mode switch 90 to switch the control mode to non-synchronized control mode, an ON command signal output from the bucket assist mode switch 91 to switch the control mode to bucket assist mode, and an ON command signal output from the monitor switch 92 to activate the monitor 120, which will be described later.

[0069] Furthermore, the controller 70 receives command signals corresponding to the operator's operations (operator operations in Figure 5). Specifically, the controller 70 receives command signals corresponding to the amount of lever operation by the operator output from the first winch operating device body 51B, command signals corresponding to the amount of lever operation by the operator output from the second winch operating device body 53B, command signals corresponding to the amount of brake operation by the operator output from the first brake operating device body 52B, and command signals corresponding to the amount of brake operation by the operator output from the second brake operating device body 54B (see Figure 2).

[0070] The controller 70 outputs command signals to various proportional valves (61A, 61B, 62, 63A, 63B, 64) and command signals related to the display on the monitor 120, which are calculated by the brake force adjustment unit 75 and the drum motion control unit 76.

[0071] [Method for calculating the degree of opening / closing α] The controller 70 has a function to determine the open / closed state of the bucket device 10 and to notify the operator of the determined open / closed state of the bucket device 10. The open / closed state of the bucket device 10 is determined based on the degree of opening / closing α of the bucket device 10. The open / closed state determination unit 71 calculates the degree of opening / closing α of the bucket device 10 and determines the open / closed state of the bucket device 10. The open / closed state determination unit 71 calculates the degree of opening / closing α from the following equation (1). In equation (1), ΔL is the difference between the first payout amount Lm of the first winch rope R1 and the second payout amount La of the second winch rope R2 (hereinafter, relative difference ΔL), and is calculated from the following equation (2). In the following explanation, the first payout amount Lm of the first winch rope R1 and the second payout amount La of the second winch rope R2 will be considered positive when the bucket device 10 is lowered (i.e., when the bucket device 10 is descending), and the signs of the first payout amount Lm and the second payout amount La will be considered negative when the bucket device 10 is raised (i.e., when the bucket device 10 is ascending).

[0072] α=(ΔL-ΔLmin) / (ΔLmax-ΔLmin)×100...(1) ΔL=Lm-La...(2)

[0073] In equation (1), ΔLmax is the relative difference (hereinafter referred to as the maximum relative difference ΔLmax) between the amount Lm of the first winch rope R1 and the amount La of the second winch rope R2 when the bucket device 10 is fully open (hereinafter referred to as the fully open state). Also, ΔLmin is the relative difference (hereinafter referred to as the minimum relative difference ΔLmin) between the amount Lm of the first winch rope R1 and the amount La of the second winch rope R2 when the bucket device 10 is fully closed (hereinafter referred to as the fully closed state). The maximum relative difference ΔLmax and the minimum relative difference ΔLmin are values ​​set in advance by the operator.

[0074] The opening / closing state determination unit 71 calculates the degree of opening / closing α of the bucket device 10 by applying the relative difference ΔL, which is calculated as needed, the maximum relative difference ΔLmax, which is set when the bucket device 10 is in a fully open state, and the minimum relative difference ΔLmin, which is set when the bucket device 10 is in a fully closed state, to equation (1). From equation (1), it is normalized so that when the relative difference ΔL is the maximum relative difference ΔLmax, the degree of opening / closing α is 100%, and when the relative difference ΔL is the minimum relative difference ΔLmin, the degree of opening / closing α is 0%.

[0075] Figure 6 shows the state of the bucket device 10 in the fully open and fully closed states. The right diagram of Figure 6 shows the fully open state, and the left diagram of Figure 6 shows the fully closed state. In the fully open state of the bucket device 10 shown in the right diagram of Figure 6, the first winch rope R1 is loose, and the bucket device 10 is supported by the second winch rope R2. At this time, the lower ends of the pair of buckets 13 of the bucket device 10 are furthest apart. As the first winch rope R1 is wound up from this state, the first winch rope R1 becomes taut, and as the first winch rope R1 is further wound up, the bucket device 10 is gradually closed. When the bucket device 10 is completely closed, it is in the state shown in the left diagram of Figure 6, where the first winch rope R1 is taut, while the second winch rope R2 is loose. At this time, the bucket device 10 is supported by the first winch rope R1, and the lower ends of the pair of buckets 13 of the bucket device 10 are adjacent to each other. The relative difference ΔL increases as the bucket device 10 transitions from a closed state to an open state, and the maximum relative difference ΔLmax in the fully open state becomes greater than the minimum relative difference ΔLmin in the fully closed state.

[0076] Here, it is preferable that the maximum relative difference ΔLmax is set based on the state in which the bucket device 10 is fully open as shown in the right diagram of Figure 6, and there is almost no slack in the first winch rope R1. It is also preferable that the minimum relative difference ΔLmin is set based on the state in which the bucket device 10 is fully closed as shown in the left diagram of Figure 6, and there is almost no slack in the second winch rope R2. The maximum relative difference ΔLmax and the minimum relative difference ΔLmin are set in advance by the operator and then stored, for example, in a memory unit 78 built into the controller 70. Alternatively, the maximum relative difference ΔLmax and the minimum relative difference ΔLmin may be stored in a memory unit provided separately from the controller 70. The method for setting the maximum relative difference ΔLmax and the minimum relative difference ΔLmin will be described later. Note that the maximum relative difference ΔLmax corresponds to the first reference value of this disclosure, and the minimum relative difference ΔLmin corresponds to the second reference value of this disclosure.

[0077] The first payout amount Lm of the first winch rope R1 is estimated from the following equation (3). In equation (3), Rm is the design effective radius of the first winch drum DR1. In equation (3), nm is the first rotation amount, which is the number of rotations of the first winch drum DR1 from a reference. In equation (3), once the effective radius Rm is set, the first payout amount Lm of the first winch rope R1 is calculated from the first rotation amount nm of the first winch drum DR1 detected by the first rotation sensor 81. Since the first payout amount Lm is calculated from the first rotation amount nm of the first winch drum DR1 detected by the first rotation sensor 81, the first rotation sensor 81 functions as a first detector for detecting the first payout amount in this disclosure.

[0078] Lm=Rm×nm...(3)

[0079] The second payout amount La of the second winch rope R2 is estimated from the following equation (4). In equation (4), Ra is the design effective radius of the second winch drum DR2. In equation (4), na is the second rotation amount, which is the number of rotations of the second winch drum DR2 from the reference. In equation (4), once the effective radius Ra is set, the second payout amount La of the second winch rope R2 is calculated from the second rotation amount na of the second winch drum DR2 detected by the second rotation sensor 82. Since the second payout amount La is calculated from the second rotation amount na of the second winch drum DR2 detected by the second rotation sensor 82, the second rotation sensor 82 functions as a second detector for detecting the second payout amount in this disclosure.

[0080] La=Ra×na...(4)

[0081] As a result, the first payout amount Lm of the first winch rope R1 calculated from equation (3) and the second payout amount La of the second winch rope R2 calculated from equation (4) are applied to equation (2) to calculate the relative difference ΔL. Furthermore, the degree of opening and closing α is obtained by applying the relative difference ΔL to equation (1).

[0082] Figure 7 shows an example of the change in the degree of opening / closing α of the bucket device 10 during operation, calculated by equation (1). In Figure 7, the horizontal axis represents time t [sec] and the vertical axis represents the degree of opening / closing α [%]. A degree of opening / closing α of 100% corresponds to the bucket device 10 being fully open and the relative difference ΔL being the preset maximum relative difference ΔLmax. A degree of opening / closing α of 0% corresponds to the bucket device 10 being fully closed and the relative difference ΔL being the preset minimum relative difference ΔLmin.

[0083] In Figure 7, as the bucket device 10 is opened, that is, as the first winch rope R1 is paid out, the first payout amount Lm increases and the degree of opening / closing α increases toward 100%. When the degree of opening / closing α reaches 100%, the bucket device 10 is fully open, and the relative difference ΔL becomes the maximum relative difference ΔLmax. If the bucket device 10 is operated further in the opening direction from this state, that is, as the first winch rope R1 is paid out, slack occurs in the first winch rope R1, and the relative difference ΔL exceeds the maximum relative difference ΔLmax, resulting in an over-open state.

[0084] Furthermore, as the bucket device 10 is closed, that is, as the first winch rope R1 is wound up, the first payout amount Lm decreases and the degree of opening / closing α decreases toward 0%. When the degree of opening / closing α reaches 0%, the bucket device 10 is in a fully closed state, and the relative difference ΔL becomes the minimum relative difference ΔLmin. If the bucket device 10 is operated further in the closing direction from this state, that is, as the first winch rope R1 is wound up, slack occurs in the second winch rope R2, and the relative difference ΔL becomes smaller than the minimum relative difference ΔLmin, resulting in an over-closed state.

[0085] In the over-open state described above, the first winch rope R1 becomes excessively loose, and in the over-closed state described above, the second winch rope R2 becomes excessively loose, which may cause the ropes to become tangled and twisted. Although the over-open and over-closed states can be prevented by visually inspecting the bucket device 10, in some work sites, obstacles may prevent visual inspection of the bucket device 10, making it impossible to ascertain its condition.

[0086] In contrast, in the first embodiment, in order to understand the open / closed state of the bucket device 10 even at a work site where the bucket device 10 cannot be seen, the controller 70 notifies the operator of the degree of open / closed state α of the bucket device 10. Specifically, the controller 70 notifies the operator of the open / closed state of the bucket device 10 by displaying the degree of open / closed state α of the bucket device 10 on the monitor 120. The monitor 120 may be, for example, a monitor located inside the cab or a monitor located outside the cab. For example, when the crane 100 is remotely operated, it is displayed on a monitor located in the remote operation room.

[0087] The screen display control unit 72 acquires the degree of opening / closing α of the bucket device 10 determined (calculated) by the opening / closing state determination unit 71, and displays the acquired degree of opening / closing α of the bucket device 10 on the monitor 120, thereby informing the operator of the degree of opening / closing α of the bucket device 10.

[0088] Figure 8 shows an example of a screen displayed on the monitor 120 based on the control of the screen display control unit 72. The monitor 120 displays the degree of opening / closing α, which is calculated as needed by the opening / closing state determination unit 71. The left side of Figure 8 shows an example of the bucket device 10 with an opening / closing degree α of 60%. The monitor 120 displays the degree of opening / closing α as a number (60%). The monitor 120 also displays the magnitude of the degree of opening / closing α as a diagram. For example, as shown in Figure 8, the degree of opening / closing α is displayed using a gauge (bar graph). In Figure 8, the longer the gauge is to the right, the larger the degree of opening / closing α is.

[0089] The right-hand diagram of Figure 8 shows an example where the opening degree α is 110%. The opening degree α is displayed numerically (110%) on the monitor 120. The magnitude of the opening degree α is also displayed as a gauge (bar graph) at the top of the monitor 120. As shown in the right-hand diagram of Figure 8, since the opening degree α is 110%, the gauge display exceeds 100%. In such an over-open state where the opening degree α exceeds 100%, the operator may be notified of the over-open state by changing the color of the gauge display or flashing the gauge, compared to when the opening degree α is between 0% and 100%. Similarly, in the case of an over-closed state where the opening degree α is less than 0%, the operator may be notified of the over-closed state by changing the color of the gauge or flashing the gauge. Furthermore, the screen display control unit 72 may notify the operator that the bucket device 10 is in an over-open or over-closed state by generating a warning sound or voice from the alarm device 126.

[0090] As described above, the display of the opening / closing degree α on the monitor 120 allows the operator to understand the status of the bucket device 10 from the monitor 120, even in work sites where the bucket device 10 cannot be visually inspected. Furthermore, the display of the opening / closing degree α as a diagram makes it easier for the operator to understand the status of the bucket device 10. In addition, if the opening / closing degree α exceeds 100% (over-opening) or the opening / closing degree α falls below 0% (over-closed), the display is changed or an audible alert is generated, allowing the operator to quickly recognize the occurrence of the over-opening or over-closed condition.

[0091] The brake force adjustment unit 75 adjusts the first brake force and the second brake force. When the control mode is set to synchronized control mode, a first brake operation is applied to the first brake operation pedal 52A to reduce the first brake force, and the open / closed state determination unit 71 determines that the bucket device 10 is in the open state, the brake force adjustment unit 75 performs the following open-down control. In the open-down control, the first brake force and the second brake force are controlled so that the bucket device 10 descends by its own weight while maintaining the open state of the bucket device 10. Furthermore, when the control mode is set to synchronized control mode, a first brake operation is applied to the first brake operation pedal 52A to reduce the first brake force, and the open / closed state determination unit 71 determines that the bucket device 10 is in the closed state, the brake force adjustment unit 75 performs the following closed-down control. In the closed-down control, the brake force adjustment unit 75 adjusts the first brake force and the second brake force so that the bucket device 10 descends while maintaining the closed state of the bucket device 10.

[0092] The drum operation control unit 76 controls the operation of the first winch drum DR1 and 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 second winch drum DR2 are controlled based on a first rotational operation given to the first winch operating device 51.

[0093] Specifically, when the control mode is set to synchronized control mode and a first unwinding operation is applied to the first winch operating lever 51A of the first winch operating device 51, the drum operation control unit 76 controls the operation of the first winch drum DR1 and the second winch drum DR2 so that the bucket device 10 descends while maintaining the open / closed state of the bucket device 10. Also, when the control mode is set to synchronized control mode and a first winding operation is applied to the first winch operating lever 51A of the first winch operating device 51, the drum operation control unit 76 controls the operation of the first winch drum DR1 and the second winch drum DR2 so that the bucket device 10 rises while maintaining the open / closed state of the bucket device 10.

[0094] [Initial Condition Setting] Next, the method for setting the maximum relative difference ΔLmax and the minimum relative difference ΔLmin will be explained. The condition setting unit 77 has the function of setting the maximum relative difference ΔLmax and the minimum relative difference ΔLmin, which are used when the opening / closing degree α is calculated by the opening / closing state determination unit 71.

[0095] When the condition setting unit 77 receives an ON command signal from the monitor switch 92, for example, to activate the monitor 120, it starts setting the maximum relative difference ΔLmax and the minimum relative difference ΔLmin. The condition setting unit 77 outputs a command to the screen display control unit 72 to start setting the maximum relative difference ΔLmax when the bucket device 10 is at a predetermined lifting height. Upon receiving the above command, the screen display control unit 72 displays an image on the monitor 120 as shown in the left diagram of Figure 9.

[0096] The left diagram in Figure 9 is an example of an image displayed on the monitor 120 when setting the maximum relative difference ΔLmax. At the bottom of the monitor 120, text instructions are displayed indicating that the bucket device 10 should be opened (to the fully open state) to the extent that the first winch rope R1 and the second winch rope R2 do not slacken. On the left side of the monitor 120, an image diagram shows a preferred example (right) and an unpredictable example (left) of the bucket device 10 being in the fully open state. The preferred example is when the bucket device 10 is fully open and the first winch rope R1 and the second winch rope R2 are not slack. The unpredictable example is when the bucket device 10 is fully open and the first winch rope R1 is slack. The left diagram in Figure 9 also shows the OK button 122, which is selected when the adjustment of the bucket device 10 is complete, and the BACK button 124, which returns to the previous setting.

[0097] The operator operates the first winch operating lever 51A of the first winch operating device 51 and the second winch operating lever 53A of the second winch operating device 53 in accordance with the display on the monitor 120 so that the bucket device 10 is fully open. When the operator confirms that the bucket device 10 is fully open with the first winch rope R1 and the second winch rope R2 not slackening, the operator selects the OK button 122. When the OK button 122 is selected, the condition setting unit 77 obtains the first payout amount Lm of the first winch rope R1 and the second payout amount La of the second winch rope R2 in this state and calculates the relative difference ΔL from equation (2). The condition setting unit 77 sets the calculated relative difference ΔL as the maximum relative difference ΔLmax. The condition setting unit 77 stores the set maximum relative difference ΔLmax in the storage unit 78.

[0098] Next, the condition setting unit 77 starts setting the minimum relative difference ΔLmin. The condition setting unit 77 outputs a command to the screen display control unit 72 to start setting the minimum relative difference ΔLmin when the bucket device 10 is at a predetermined lifting height. Upon receiving the above command, the screen display control unit 72 displays an image on the monitor 120 as shown in the right-hand figure of Figure 9.

[0099] The right-hand diagram in Figure 9 shows an example of an image displayed on the monitor 120 when setting the minimum relative difference ΔLmin. At the bottom of the monitor 120, text instructions are displayed indicating that the bucket device 10 should be closed (fully closed) to the extent that the first winch rope R1 and the second winch rope R2 do not loosen. On the left side of the monitor 120, an image diagram shows a preferred example (right) and an unpredictable example (left) of the bucket device 10 being fully closed. The preferred example is when the bucket device 10 is fully closed and the first winch rope R1 and the second winch rope R2 are not loose. The unpredictable example is when the bucket device 10 is fully closed and the second winch rope R2 is loose. The right-hand diagram in Figure 9 also shows the OK button 122, which is selected when the adjustment of the bucket device 10 is complete, and the BACK button 124, which returns to the previous setting.

[0100] The operator operates the first winch operating lever 51A and the second winch operating lever 53A according to the display on the monitor 120 so that the bucket device 10 is fully closed. When the operator confirms that the bucket device 10 is fully closed with the first winch rope R1 and the second winch rope R2 not slackening, the operator selects the OK button 122. When the OK button 122 is selected, the condition setting unit 77 obtains the first payout amount Lm of the first winch rope R1 and the second payout amount La of the second winch rope R2 in this state and calculates the relative difference ΔL from equation (2). The condition setting unit 77 sets the calculated relative difference ΔL as the minimum relative difference ΔLmin. The condition setting unit 77 also stores the set minimum relative difference ΔLmin in the storage unit 78.

[0101] Incidentally, the winding layers of the first winch rope R1 in the first winch drum DR1 change according to the first rotation amount nm of the first winch rope R1. In connection with this, the actual effective radius Rm of the first winch drum DR1 also changes according to the first rotation amount nm. As a result, there is an error Δrm in the effective radius Rm of the first winch drum DR1. The effective radius Rmer considering the error Δrm is shown in equation (5) below. For similar reasons, there is also an error Δra in the effective radius Ra of the second winch drum DR2. The effective radius Raer considering the error Δra is shown in equation (6) below.

[0102] Rmer=Rm+Δrm...(5) Raer=Ra+Δra...(6)

[0103] In order to reduce the effects of these errors Δrm and Δra, the maximum relative difference ΔLmax (hereinafter referred to as the maximum relative difference ΔLmaxre) and the minimum relative difference ΔLmin (hereinafter referred to as the minimum relative difference ΔLminre), taking into account the above errors Δrm and Δra, are determined as follows.

[0104] The maximum relative difference ΔLmaxre is set as the average of the maximum relative difference ΔLmax(High) set when the bucket device 10 is at its highest lifting height High and the maximum relative difference ΔLmax(Hlow) set when the bucket device 10 is at its lowest lifting height Low. Specifically, the maximum relative difference ΔLmaxre is calculated from the following equation (7). The minimum relative difference ΔLminre is set as the average of the minimum relative difference ΔLmin(High) set when the bucket device 10 is at its highest lifting height High and the minimum relative difference ΔLmin(Hlow) set when the bucket device 10 is at its lowest lifting height Low. Specifically, the minimum relative difference ΔLminre is calculated from the following equation (8).

[0105] ΔLmaxre=(ΔLmax(Hhigh)+ΔLmax(Hlow)) / 2...(7) ΔLminre=(ΔLmin(Hhigh)+ΔLmin(Hlow)) / 2...(8)

[0106] Figure 10 shows the bucket device 10 at its maximum lift height Hhigh and at its minimum lift height Hlow. The maximum lift height Hhigh is the highest position the bucket device 10 can reach. That is, the maximum lift height Hhigh is the value at which the rotation amounts nm and na of each winch drum DR1 and DR2 are minimized, and the distance between the bucket device 10 and the ground G is maximized. The minimum lift height Hlow is the lowest position the bucket device 10 can reach from the ground G. That is, the minimum lift height Hlow is the position at which the rotation amounts nm and na of each winch drum DR1 and DR2 are maximized within the range where the bucket device 10 is away from the ground G. In addition, when defining the maximum lifting height Hhigh and minimum lifting height Hlow of the bucket device 10, the angle θ of the luffing member 104 with respect to the horizontal line (boom angle θ) is predetermined as a reference angle (for example, 45 degrees).

[0107] As described above, by setting the maximum relative difference ΔLmaxre and the minimum relative difference ΔLminre to the average values ​​of the maximum head Hhigh and the minimum head Hlow, the influence of errors Δrm and Δra can be reduced.

[0108] When setting the maximum relative difference ΔLmax and the minimum relative difference ΔLmin, the condition setting unit 77 outputs a command to prompt the operator to move the bucket device 10 to, for example, the maximum lifting height Hhigh. Specifically, the condition setting unit 77 issues a command to the screen display control unit 72 to display on the monitor 120 an instruction for the operator to move the bucket device 10 to the maximum lifting height Hhigh.

[0109] The screen display control unit 72 receives the above command from the condition setting unit 77 and displays an image on the monitor 120 as shown in the left diagram of Figure 11. In the upper right corner of the monitor 120, the instruction to raise the bucket device 10, that is, to move the bucket device 10 to the maximum lifting height Hhigh, is displayed in text. Also, on the left side of the monitor 120, a simplified diagram illustrating the above instruction is displayed. Furthermore, in the lower right corner of the monitor 120, the OK button 122, which is selected when the adjustment of the position of the bucket device 10 is complete, and the BACK button 124, which returns to the previous setting, are displayed side by side.

[0110] The operator raises the bucket device 10 to the maximum lift height Hhigh according to the display on the monitor 120, and then selects the OK button 122. After the OK button 122 is selected, the condition setting unit 77 sets the maximum relative difference ΔLmax(Hhigh) and the minimum relative difference ΔLmin(Hhigh) at the maximum lift height Hhigh.

[0111] Next, the condition setting unit 77 outputs a command to prompt the operator to move the bucket device 10 to the lowest lift height Hlow. Specifically, the condition setting unit 77 issues a command to the screen display control unit 72 to display on the monitor 120 an instruction for the operator to move the bucket device 10 to the lowest lift height Hlow.

[0112] The screen display control unit 72 receives the above command from the condition setting unit 77 and displays an image on the monitor 120 as shown in the right-hand diagram of Figure 11. In the upper right corner of the monitor 120, a text instruction is displayed to lower the bucket device 10, that is, to move the bucket device 10 to the lowest lifting height, Hlow. Also, on the left side of the monitor 120, a simplified diagram illustrating the above instruction is displayed. Furthermore, in the lower right corner of the monitor 120, an OK button 122 to be selected when the adjustment of the position of the bucket device 10 is complete and a BACK button 124 to return to the previous setting are displayed side by side.

[0113] The operator lowers the bucket device 10 to the minimum lift height Hlow according to the display on the monitor 120, and then selects the OK button 122. After the OK button 122 is selected, the condition setting unit 77 sets the maximum relative difference ΔLmax(Hlow) and the minimum relative difference ΔLmin(Hlow) at the minimum lift height Hlow.

[0114] By performing the above operations, the maximum relative difference ΔLmax(Hhigh) and minimum relative difference ΔLmin(Hhigh) at the highest head height Hhigh, and the maximum relative difference ΔLmax(Hlow) and minimum relative difference ΔLmin(Hlow) at the lowest head height Hlow are obtained. Then, the condition setting unit 77 calculates the maximum relative difference ΔLmaxre and minimum relative difference ΔLminre from equations (7) and (8), taking into account the errors Δrm and Δra. When calculating the degree of opening / closing α, the use of the above maximum relative difference ΔLmaxre and minimum relative difference ΔLminre reduces the influence of the errors Δrm and Δra, improving the calculation accuracy of the degree of opening / closing α.

[0115] [Determination of the rope responsible for opening and closing] The opening / closing rope determination unit 79 also has the function of determining whether the rope responsible for opening and closing the bucket device 10 is the first winch rope R1 (main winding rope) or the second winch rope R2 (auxiliary winding rope). Depending on how the winch ropes R1 and R2 are connected to the bucket device 10, the first winch rope R1 (main winding rope) may become the rope responsible for opening and closing the bucket device 10, or the second winch rope R2 (auxiliary winding rope) may become the rope responsible for opening and closing the bucket device 10. For example, it is possible that the rope responsible for opening and closing the bucket device 10 may be different from the rope intended by the operator. Therefore, the opening / closing rope determination unit 79 determines the rope responsible for opening and closing the bucket device 10 in accordance with the settings of the maximum relative difference ΔLmax and minimum relative difference ΔLmin described above.

[0116] The opening / closing rope determination unit 79 calculates the first change amount ΔLm and the second change amount ΔLa without changing the lifting height of the bucket device 10. Specifically, the opening / closing rope determination unit 79 calculates, for example, the first change amount ΔLm of the first payout amount Lm of the first winch rope R1 and the second change amount ΔLa of the second payout amount La of the second winch rope R2 when the bucket device 10 is at its lowest lifting height Hlow. The first change amount ΔLm is calculated from the following equation (9). In equation (9), Lmopn is the first payout amount Lm when the bucket device 10 is in the fully open state, and Lmcls is the first payout amount Lm when the bucket device 10 is in the fully closed state. The second change amount ΔLa is calculated from the following equation (10). In equation (10), Laopn is the second payout amount La when the bucket device 10 is fully open, and Lacls is the second payout amount La when the bucket device 10 is fully closed. From equation (9), the first change amount ΔLm is the difference between the first payout amount Lmopn of the first winch rope R1 when the bucket device 10 is fully open and the first payout amount Lmcls of the first winch rope R1 when the bucket device 10 is fully closed. Also, from equation (10), the second change amount ΔLa is the difference between the second payout amount Laopn of the second winch rope R2 when the bucket device 10 is fully open and the second payout amount Lacls when the bucket device 10 is fully closed.

[0117] ΔLm=Lmopn-Lmcls...(9) ΔLa=Laopn-Lacls...(10)

[0118] The opening / closing rope determination unit 79 calculates the first change amount ΔLm and the second change amount ΔLa, and then determines whether the calculated first change amount ΔLm is greater than the second change amount ΔLa. If the first change amount ΔLm is greater than the second change amount ΔLa, the opening / closing rope determination unit 79 determines that the first winch rope R1 is responsible for opening and closing the bucket device 10, and the second winch rope R2 is responsible for supporting the bucket device 10. On the other hand, if the first change amount ΔLm is less than the second change amount ΔLa, the unit determines that the second winch rope R2 is responsible for opening and closing, and the first winch rope R1 is responsible for supporting the bucket device 10.

[0119] Figure 12 is a flowchart illustrating the control operations performed by the opening / closing rope determination unit 79 when determining the rope responsible for opening and closing the bucket device 10. The flowchart in Figure 12 is performed during the initial setup, for example, when the bucket device 10 is at its lowest lifting height, Hlow.

[0120] First, the opening / closing rope determination unit 79 calculates the change in the first payout amount Lm of the first winch rope R1 ΔLm from the first payout amount Lmopn of the first winch rope R1 when the bucket device 10 is fully open and the first payout amount Lmcls of the first winch rope R1 when the bucket device 10 is fully closed (step S10). Next, the opening / closing rope determination unit 79 calculates the change in the second payout amount La of the second winch rope R2 ΔLa from the second payout amount Laopn of the second winch rope R2 when the bucket device 10 is fully open and the second payout amount Lacls of the second winch rope R2 when the bucket device 10 is fully closed (step S20). Next, the opening / closing rope determination unit 79 determines whether the change in ΔLm calculated in step S10 is greater than the change in ΔLa calculated in step S20 (step S30). If the amount of change ΔLm is greater than the amount of change ΔLa (Yes in step S30), the opening / closing rope determination unit 79 determines that the first winch rope R1 is the rope responsible for opening and closing the bucket device 10 (step S40). On the other hand, if the amount of change ΔLm is less than the amount of change ΔLa (No in step S30), the opening / closing rope determination unit 79 determines that the second winch rope R2 is the rope responsible for opening and closing the bucket device 10 (step S50).

[0121] Based on the flowchart in Figure 12, for example, if the first winch rope R1 is determined to be the rope responsible for opening and closing the bucket device 10, the opening / closing rope determination unit 79 issues a command to the screen display control unit 72 to display an image as shown in Figure 13 on the monitor 120 in order to confirm whether this determination is what the operator intended. The screen display control unit 72 displays an image as shown in Figure 13 on the monitor 120 in accordance with the above command. If the rope responsible for opening and closing the bucket device 10 is determined to be the first winch rope R1, the connection destination of the rope responsible for opening and closing will be displayed as "Main winding (first winch rope R1)" as shown in Figure 13. If the rope responsible for opening and closing the bucket device 10 is determined to be the second winch rope R2, the connection destination of the rope responsible for opening and closing will be displayed as "Auxiliary winding (second winch rope R2)".

[0122] If the display on the monitor 120 matches the operator's intention, the operator selects the OK button 122. On the other hand, if the display on the monitor 120 differs from the operator's intention, the operator selects the BACK button 124 and reconfirms the rope connection destination. This operation prevents the operator from using the wrong rope to open and close the bucket device 10.

[0123] Figure 14 is a flowchart illustrating the control operations of the controller 70, which are performed when the maximum relative difference ΔLmax and the minimum relative difference ΔLmin are set, and when the rope responsible for opening and closing the bucket device 10 is determined. In Figure 14, the areas enclosed by dashed lines correspond to the control operations performed when the bucket device 10 is at its highest lifting height Hhigh, and the areas enclosed by dashed lines correspond to the control operations performed when the bucket device 10 is at its lowest lifting height Hlow.

[0124] To perform the initial setup, first, the controller 70 displays the left diagram of Figure 11 on the monitor 120 in order to move the bucket device 10 to the highest lifting height (step S100). The operator moves the bucket device 10 to the highest lifting height according to the display on the monitor 120. Next, the controller 70 determines whether the OK button 122 or the BACK button 124 displayed in the left diagram of Figure 11 has been selected. If the BACK button 124 is selected (NO in step S110), the controller 70 completes the initial setup and then performs the initial setup again from the beginning. If the OK button 122 is selected in step S110 (YES in S110), the controller 70 displays the left diagram of Figure 9 on the monitor 120 (step S120). The operator fully opens the bucket device 10 according to the display on the monitor 120. Next, the controller 70 determines which of the OK button 122 and BACK button 124 displayed on the monitor 120 has been selected (step S130). If the BACK button 124 is selected (NO in step S130), the controller 70 returns to step S100. If the OK button 122 is selected (YES in S130), the controller 70 stores the maximum relative difference ΔLmax (Hhigh) calculated when the bucket device 10 is in the fully open state in the storage unit 78 (step S140). Next, the controller 70 displays the right diagram of Figure 9 on the monitor 120 (step S150). The operator closes the bucket device 10 in the fully closed state according to the display on the monitor 120. Next, the controller 70 determines which of the OK button 122 and BACK button 124 displayed on the monitor 120 has been selected (step S160). If the BACK button 124 is selected (NO in step S160), the controller 70 returns to S120. If the OK button 122 is selected (YES in step S160), the controller 70 stores the minimum relative difference ΔLmin(Hhigh) calculated when the bucket device 10 is in a fully closed state in the storage unit 78 (step S170).

[0125] Next, in order to move the bucket device 10 to the lowest lift height (Hlow), the controller 70 displays the right diagram of Figure 11 on the monitor 120 (step S180). The operator moves the bucket device 10 to the lowest lift height (Hlow) according to the display on the monitor 120. Next, the controller 70 determines which of the OK button 122 and BACK button 124 displayed on the monitor 120 has been selected (step S190). If the BACK button 124 is selected (NO in S190), the controller 70 returns to step S150. If the OK button 122 is selected (YES in step S190), the controller 70 displays the left diagram of Figure 9 on the monitor 120 (step S200). The operator fully opens the bucket device 10 according to the display on the monitor 120. Next, the controller 70 determines which of the OK button 122 and BACK button 124 displayed on the monitor 120 has been selected (step S210). If the BACK button 124 is selected (NO in step S210), the controller 70 returns to step S180. If the OK button 122 is selected (YES in step S210), the controller 70 stores the maximum relative difference ΔLmax(Hlow) calculated when the bucket device 10 is fully open in the storage unit 78. Furthermore, the controller 70 stores the first payout amount Lmopn of the first winch rope R1 and the second payout amount Laopn of the second winch rope R2 in the storage unit 78 when the bucket is fully open. Next, the controller 70 displays the right diagram of Figure 9 on the monitor 120 (step S230). The operator closes the bucket device 10 completely according to the display on the monitor 120. Next, the controller 70 determines which of the OK button 122 and BACK button 124 displayed on the monitor 120 was selected (step S240). If the BACK button 124 is selected (NO in step S240), the controller 70 returns to step S200. If the OK button 122 is selected (YES in step S240), the controller 70 stores the minimum relative difference ΔLmin(Hlow), which is calculated when the bucket device 10 is in a fully closed state, in the storage unit 78 (step S250).Furthermore, the controller 70 stores the first payout amount Lmcls of the first winch rope R1 and the second payout amount Lacls of the second winch rope R2 in the storage unit 78 when the bucket is fully closed (step S250). Next, the controller 70 calculates the final maximum relative difference ΔLmaxre and minimum relative difference ΔLminre using equations (7) and (8) (step S260). Then, the controller 70 determines which rope is responsible for opening and closing the bucket device 10 according to the flowchart in Figure 12 described above, and then completes the initial setup.

[0126] [Second Embodiment] In the first embodiment described above, the degree of opening and closing α of the bucket device 10 was calculated using the relative difference ΔL (= Lm - La) between the first payout amount Lm and the second payout amount La. Alternatively, the opening / closing state determination unit 71 may calculate the degree of opening and closing α using the difference in lifting values ​​ΔLF (= ΔLFm - ΔLFa), which is the difference between the lifting value of the first winch rope R1 (first lifting value LFm) and the lifting value of the second winch rope R2 (second lifting value LFa).

[0127] The lifting height value LF referred to here is different from the lifting height of the bucket device 10 (height from the ground G), and corresponds to the change in lifting height based on a specific state. For example, a specific state may be set to a state where the first winch drum DR1 is at 0 rotations, the second winch drum DR2 is at 0 rotations, and the luffing member angle θ (boom angle θ) of the luffing member 104 with respect to the horizontal line is 45 degrees. The state of "first winch drum DR1 at 0 rotations" is the state in which the first winch rope R1 is fully extended from the first winch drum DR1. The state of "second winch drum DR2 at 0 rotations" is the state in which the second winch rope R2 is fully extended from the second winch drum DR2. When the lifting height value of the first winch rope R1 in this specific state is taken as the reference (zero), the first lifting height value LFm is the change in lifting height from that reference. Similarly, when the lifting height of the second winch rope R2 in the aforementioned specific state is taken as the baseline (zero), the second lifting height LFa is the amount of change in the lifting height from that baseline.

[0128] The controller 70 can calculate the first lifting height value LFm of the first winch rope R1 based on the amount of rotation nm of the first winch drum DR1 detected by the first rotation sensor 81 and the luffing member angle θ detected by the luffing member angle detector 83 (see Figure 10). Similarly, the controller 70 can calculate the second lifting height value LFa of the second winch rope R2 based on the amount of rotation na of the second winch drum DR2 detected by the second rotation sensor 82 and the luffing member angle θ. Specifically, it is as follows.

[0129] The first lifting height value LFm of the first winch rope R1 changes not only according to the amount of the first winch rope R1 unfurled from the first winch drum DR1, but also according to the luffing member angle θ of the luffing member 104. Similarly, the second lifting height value LFa of the second winch rope R2 changes not only according to the amount of the second winch rope R2 unfurled from the second winch drum DR2, but also according to the luffing member angle θ of the luffing member 104.

[0130] The controller 70 may pre-store specification data including the length of the luffing member 104, data relating to the relative position of the first winch drum DR1 with respect to a specific part of the luffing member 104 (for example, the base end of the luffing member 104), and data relating to the relative position of the second winch drum DR2 with respect to the specific part of the luffing member 104. In this case, the controller 70 can calculate a first distance and a second distance that change according to the luffing member angle θ from the geometric positional relationship of the luffing member 104, the first winch drum DR1, and the second winch drum DR2. The first distance is the distance from the first winch drum DR1 to a predetermined first part of the luffing member 104 (for example, the upper end of the luffing member 104). The second distance is the distance from the second winch drum DR2 to a predetermined second part of the luffing member 104 (for example, the upper end of the luffing member 104). Furthermore, the controller 70 may pre-store a relational expression representing the relationship between the luffing member angle θ and the first distance, and a relational expression representing the relationship between the luffing member angle θ and the second distance. In this case, the controller 70 may calculate the first distance and the second distance using the luffing member angle θ detected by the luffing member angle detector 83 and the two relational expressions described above.

[0131] The controller 70 uses information such as specification data including the length of the luffing member 104, data regarding the relative position of the first winch drum DR1 with respect to the specific part of the luffing member 104, and data regarding the relative position of the second winch drum DR2 with respect to the specific part of the luffing member 104, as well as detection results input to the controller 70 from the rotation sensors 81 and 82, and the luffing member angle θ of the luffing member 104 input to the controller 70 from the luffing member angle detector 83, to calculate the first lifting height value LFm of the first winch rope R1 and the second lifting height value LFa of the second winch rope R2, respectively.

[0132] Specifically, for example, the controller 70 may calculate the first lifting height value LFm of the first winch rope R1 based on the change in the first distance ΔL1 for the specific state, the change in the height position of the upper end of the luffing member 104 ΔH1 for the specific state, and the change in the amount of the first winch rope R1 extended ΔR1 for the specific state. The controller 70 may also calculate the first lifting height value LFm of the first winch rope R1 using, for example, the following equation (11).

[0133] LFm=-(ΔL1+ΔH1+ΔR1)...(11)

[0134] Similarly, the controller 70 may calculate the second lifting height LFa of the second winch rope R2 based on the change in the second distance ΔL2 for the specific state, the change in the height position of the upper end of the luffing member 104 ΔH2 for the specific state, and the change in the amount of the second winch rope R2 extended ΔR2 for the specific state. The controller 70 may calculate the second lifting height LFa of the second winch rope R2 using, for example, the following equation (12).

[0135] LFa=-(ΔL2+ΔH2+ΔR2)...(12)

[0136] In the second embodiment, the opening / closing state determination unit 73 calculates the degree of opening / closing α using the following equation (13). In equation (13), the maximum lifting height difference ΔLFmax and the minimum lifting height difference ΔLFmin are preset values. The maximum lifting height difference ΔLFmax is the lifting height difference between the first lifting height value LFm of the first winch rope R1 and the second lifting height value LFa of the second winch rope R2 when the bucket device 10 is in the fully open state, and is preset in the same way as the maximum relative difference ΔLmax described above. The minimum lifting height difference ΔLFmin is the lifting height difference between the first lifting height value LFm of the first winch rope R1 and the second lifting height value LFa of the second winch rope R2 when the bucket device 10 is in the fully closed state, and is preset in the same way as the minimum relative difference ΔLmin described above. The opening / closing state determination unit 73 calculates the degree of opening / closing α of the bucket device 10 by applying the lifting height difference ΔLF, the maximum lifting height difference ΔLFmax, and the minimum lifting height difference ΔLFmin, which are calculated as needed, to equation (13). The maximum lifting height difference ΔLFmax corresponds to the first lifting height reference value of this disclosure, and the minimum lifting height difference ΔLFmin corresponds to the second lifting height reference value of this disclosure.

[0137] α=(ΔLF-ΔLFmin) / (ΔLFmax-ΔLFmin)×100 (13)

[0138] Furthermore, in order to improve the calculation accuracy of the degree of opening α, the maximum head value difference ΔLFmax may be the average of the maximum head value difference ΔLFmax(Hhigh) set when the head of the bucket device 10 is at the highest head height Hhigh and the minimum head value difference ΔLFmin(Hlow) set when the head of the bucket device 10 is at the lowest head height Hlow. Similarly, the minimum head value difference ΔLFmin may be the average of the minimum head value difference ΔLFmin(Hhigh) set when the head of the bucket device 10 is at the highest head height Hhigh and the minimum head value difference ΔLFmin(Hlow) set when the head of the bucket device 10 is at the lowest head height Hlow. This further improves the calculation accuracy of the degree of opening α.

[0139] Furthermore, the opening / closing state determination unit 73 may determine whether the bucket device 10 is in an over-open state or an over-closed state based on the lifting height difference ΔLF, the maximum lifting height difference ΔLFmax, and the minimum lifting height difference ΔLFmin. Specifically, the opening / closing state determination unit 73 determines that the bucket device 10 is in an over-open state if the lifting height difference ΔLF is greater than the maximum lifting height difference ΔLFmax, and determines that the bucket device 10 is in an over-closed state if the lifting height difference ΔLF is less than the minimum lifting height difference ΔLFmin.

[0140] Alternatively, the opening / closing rope determination unit 79 may determine which of the first winch rope R1 and the second winch rope R2 is responsible for opening and closing the bucket device 10, using the first lifting height value LFm of the first winch rope R1 and the second lifting height value LFa of the second winch rope R2.

[0141] Specifically, the opening / closing rope determination unit 79 calculates a first lift change amount ΔLFm, which is the difference (=LFmopn - LFmcls) between the first lift value LFmopn of the first winch rope R1 when the bucket device 10 is in a fully open state and the first lift value LFmcls of the first winch rope R1 when the bucket device 10 is in a fully closed state. Furthermore, the opening / closing rope determination unit 79 calculates a second lift change amount ΔLFa, which is the difference (=LFaopn - LFacls) between the second lift value LFaopn of the second winch rope R2 when the bucket device 10 is in a fully open state and the second lift value LFacls of the second winch rope R2 when the bucket device 10 is in a fully closed state. The opening / closing rope determination unit 79 determines that the first winch rope R1 is responsible for opening and closing the bucket device 10 if the calculated first lifting height change amount ΔLFm is greater than the second lifting height change amount ΔLFa. The opening / closing rope determination unit 79 also determines that the second winch rope R2 is responsible for opening and closing the bucket device 10 if the calculated first lifting height change amount ΔLFm is less than the second lifting height change amount ΔLFa. In this way, the opening / closing degree α and the determination of which rope is responsible for opening and closing the bucket device 10 can also be performed using the first lifting height value LFm of the first winch rope R1 and the second lifting height value LFa of the second winch rope R2, achieving the same operation and effect as the first embodiment. Specifically, the opening / closing degree α calculated based on the lifting height value LF is displayed on the monitor 120, thereby informing the operator of the opening / closing degree α of the bucket device 10 via the monitor 120. As a result, the status of the bucket device 10 can be grasped even when visual inspection of the bucket device 10 is difficult.

[0142] [Modification] In the first and second embodiments described above, the degree of opening / closing α was displayed as a gauge (bar graph), but this disclosure is not limited to a gauge. For example, the degree of opening / closing α may be displayed as a pie chart or a meter. In other words, any display that allows the operator to grasp the degree of opening / closing α visually is acceptable. Furthermore, it is not necessarily required to display the degree of opening / closing α using a diagram such as a gauge; the degree of opening / closing α may be displayed only as a numerical value on the monitor 120.

[0143] In the first and second embodiments described above, the bucket device 10 is first moved to the highest lifting height Hhigh, and the maximum relative difference ΔLmax(Hhigh) and minimum relative difference ΔLmin(Hhigh) are calculated. Then, the bucket device 10 is moved to the lowest lifting height Hlow, and the maximum relative difference ΔLmax(Hlow) and minimum relative difference ΔLmin(Hlow) are calculated. However, this order may be reversed. That is, in the flowchart of Figure 14, the controller 70 may first execute the control operations from step S180 to step S250, and then execute the control operations from step S100 to step S170.

[0144] In the first and second embodiments described above, the rope responsible for opening and closing the bucket device 10 was determined from the change in the first payout amount Lm of the first winch rope R1 and the change in the second payout amount La of the second winch rope R2 when the bucket device 10 is at its lowest lifting height Hlow, but the disclosure is not limited thereto. For example, the rope responsible for opening and closing the bucket device 10 may be determined from the change in the first payout amount Lm of the first winch rope R1 and the change in the second payout amount La of the second winch rope R2 when the bucket device 10 is at its highest lifting height Hhigh. Alternatively, the rope responsible for opening and closing the bucket device 10 may be determined at a predetermined position different from both the highest lifting height Hhigh and the lowest lifting height Hlow.

[0145] In the first and second embodiments described above, the final maximum relative difference ΔLmax and minimum relative difference ΔLmin were determined from the average values ​​of the maximum relative difference ΔLmax and minimum relative difference ΔLmin when the bucket device 10 is at its highest lifting height Hhigh and when the bucket device 10 is at its lowest lifting height Hlow, respectively. However, this disclosure is not limited thereto. For example, the maximum relative difference ΔLmax (Hhigh) and minimum relative difference ΔLmin (Hhigh) may be set based on the bucket device 10 being at a predetermined lifting height. Similarly, the maximum lifting value difference ΔLFmax and minimum lifting value difference ΔLFmin may also be set based on the bucket device 10 being at a predetermined lifting height.

[0146] In the first and second embodiments described above, the degree of opening / closing α was displayed on the monitor 120 to inform the operator of the open / closed state of the bucket device 10. However, other means may be used as long as they can inform the operator of the open / closed state. For example, the degree of opening / closing α may be announced audibly from a speaker or other sound-generating device. Alternatively, both the monitor 120 and the sound-generating device may be used to inform the operator of the open / closed state of the bucket device 10.

[0147] In the first and second embodiments described above, the initial setup was initiated when the monitor switch 92 for activating the monitor 120 was selected, but this disclosure is not limited thereto. For example, an initial setup switch for initiating the initial setup may be set, and the initial setup may be initiated when the initial setup switch is selected.

[0148] In the first and second embodiments described above, the bucket device 10 was mounted on a crane 100 as a construction machine, but this disclosure is not limited to cranes. This disclosure applies to any construction machine that includes a bucket device that is openable and closable and raised and lowered in accordance with the rotation of the first and second winch drums, and a first winch drum for paying out and winding up a first winch rope, and a second winch drum for paying out and winding up a second winch rope.

[0149] In the first and second embodiments described above, the storage unit 78 was built into the controller 70, but the storage unit 78 may be arranged separately from the controller 70.

[0150] In the first and second embodiments described above, the control mode of the bucket device 10 was configured to be switchable between assist mode, non-assist mode, synchronized control mode, and non-synchronized control mode. However, this disclosure is not limited to embodiments that include the above control modes. That is, this disclosure is also applicable to conventional cranes that do not have the above control modes.

[0151] In the first and second embodiments described above, the bucket control device is provided on the crane 100. However, the bucket control device in this disclosure does not necessarily have to be provided on a construction machine such as the crane 100, and may be located at a location away from the construction machine. In this case, the bucket control device is configured to be able to send and receive information between the bucket control device and the construction machine via a network such as the internet or a mobile phone network.

[0152] In the first and second embodiments described above, the luffing member 104 shown in Figure 1 is a boom having a lattice structure (lattice boom), but the luffing member may include a boom having a lattice structure and a jib having a lattice structure, or it may be an extendable boom (telescopic boom). The construction machine may be placed on the ground, on a structure, or on a ship. In any of these cases, the lower body of the construction machine may have a crawler running device as shown in Figure 1, a running device including tires, or it may be composed of a structure such as a support platform that cannot move on its own.

[0153] As described above, the first technology, including the first and second embodiments of this disclosure, provides a bucket control device and construction machinery that can grasp the status of a bucket device even in a work site where it is difficult to visually inspect the bucket device. The first technology of this disclosure includes the following first to seventh embodiments.

[0154] A bucket control device according to a first aspect of the first technology is a bucket control device for a construction machine comprising: a first winch drum for paying out and winding up a first winch rope; a second winch drum for paying out and winding up a second winch rope; and a bucket device connected to the first and second winch ropes, which is openable and closable and raised and lowered in accordance with the rotation of the first and second winch drums, the bucket control device comprising a controller for determining the open / closed state of the bucket device and notifying the operator of the determined open / closed state of the bucket device.

[0155] According to the first embodiment, the open / closed state of the bucket device determined by the controller is communicated to the operator, so that the operator can understand the status of the bucket device even in work sites where it is difficult to visually inspect the bucket device.

[0156] A bucket control device according to a second embodiment of the first technology preferably further comprises the following features in addition to the bucket control device according to the first embodiment. That is, in the bucket control device according to the second embodiment, the construction machine comprises a first detector that detects a first payout amount, which is the amount of the first winch rope paid out, or a first lifting value of the first winch rope, and a second detector that detects a second payout amount, which is the amount of the second winch rope paid out, or a second lifting value of the second winch rope, and the controller determines the difference between the first payout amount of the first winch rope and the second payout amount of the second winch rope, when the bucket device is in a fully open state. The degree of opening and closing of the bucket device is calculated based on the first reference value, which is the difference, and the second reference value, which is the difference when the bucket device is in a fully closed state. Alternatively, the controller calculates the degree of opening and closing of the bucket device based on the difference in lift values ​​between the first lift value of the first winch rope and the second lift value of the second winch rope, the first lift reference value, which is the difference in lift values ​​when the bucket device is in the fully open state, and the second lift reference value, which is the difference in lift values ​​when the bucket device is in the fully closed state.

[0157] According to the second embodiment, a first reference value for when the bucket device is fully open and a second reference value for when the bucket device is fully closed are set in advance, and the degree of opening and closing of the bucket device can be calculated in real time by detecting the first payout amount of the first winch rope and the second payout amount of the second winch rope as needed. Alternatively, a first lifting height reference value for when the bucket device is fully open and a second lifting height reference value for when the bucket device is fully closed are set in advance, and the degree of opening and closing of the bucket device can be calculated in real time by detecting the first lifting height value of the first winch rope and the second lifting height value of the second winch rope as needed.

[0158] A bucket control device according to a third aspect of the first technology preferably further comprises the following features in addition to the bucket control device according to the second aspect. That is, in the bucket control device according to the third aspect, the controller presets the first reference value and the second reference value, or the first lifting reference value and the second lifting reference value, and the controller calculates the first reference value from the difference between the first payout amount of the first winch rope and the second payout amount of the second winch rope when the bucket device is in the open state, calculates the second reference value from the difference between the first payout amount of the first winch rope and the second payout amount of the second winch rope when the bucket device is in the closed state, calculates the first lifting reference value from the difference in lifting values ​​between the first lifting value of the first winch rope and the second lifting value of the second winch rope when the bucket device is in the open state, and calculates the second lifting reference value from the difference in lifting values ​​between the first lifting value of the first winch rope and the second lifting value of the second winch rope when the bucket device is in the closed state.

[0159] According to the third embodiment, for example, by pre-setting the first reference value and the second reference value before performing the work, the first reference value and the second reference value are set to appropriate values ​​according to the work site, and the accuracy of the calculation of the degree of opening and closing is improved. Similarly, for example, by pre-setting the first lifting height reference value and the second lifting height reference value before performing the work, the first lifting height reference value and the second lifting height reference value are set to appropriate values ​​according to the work site, and the accuracy of the calculation of the degree of opening and closing is improved.

[0160] A bucket control device according to a fourth aspect of the first technology preferably further comprises the following features in addition to the bucket control device according to the third aspect. That is, in the bucket control device according to the fourth aspect, the first reference value is set to the average of a first reference value set when the lifting height of the bucket device is at a predetermined maximum lifting height and a first reference value set when the lifting height of the bucket device is at a predetermined minimum lifting height; the second reference value is set to the average of a second reference value set when the lifting height of the bucket device is at the maximum lifting height and a second reference value set when the lifting height of the bucket device is at the minimum lifting height; the first lifting height reference value is set to the average of a first lifting height reference value set when the lifting height of the bucket device is at the maximum lifting height and a first lifting height reference value set when the lifting height of the bucket device is at the minimum lifting height; and the second lifting height reference value is set to the average of a second lifting height reference value set when the lifting height of the bucket device is at the maximum lifting height and a second lifting height reference value set when the lifting height of the bucket device is at the minimum lifting height.

[0161] According to the fourth aspect, the first reference value, second reference value, first lifting height reference value, and second lifting height reference value are all set to the average value of the value set when the bucket device is at its maximum lifting height and the value set when the bucket device is at its minimum lifting height. This reduces the influence of changes in the effective radius of the first and second winch drums due to changes in the winding layers of the first and second winch drums. As a result, the calculation accuracy of the opening and closing degree of the bucket device is further improved.

[0162] A bucket control device according to a fifth embodiment of the first technology preferably further comprises the following features in a bucket control device according to any of the first to fourth embodiments. That is, in a bucket control device according to a fifth embodiment, the controller calculates a first change amount which is the difference between the first payout amount of the first winch rope when the bucket device is in an open state and the first payout amount of the first winch rope when the bucket device is in a closed state, and a second change amount which is the difference between the second payout amount of the second winch rope when the bucket device is in an open state and the second payout amount of the second winch rope when the bucket device is in a closed state. If the first change amount is greater than the second change amount, the controller determines that the first winch rope is responsible for opening and closing the bucket device, and if the first change amount is less than the second change amount, the controller determines that the second winch rope is responsible for opening and closing the bucket device.

[0163] According to the fifth embodiment, the rope responsible for opening and closing the bucket device can be determined from the first payout amount of the first winch rope and the second payout amount of the second winch rope when the bucket device is in a fully open state, and the first payout amount of the first winch rope and the second payout amount of the second winch rope when the bucket device is in a fully closed state.

[0164] A bucket control device according to the sixth aspect of the first technology preferably further comprises the following features in a bucket control device according to any of the first to fourth aspects. That is, in the bucket control device according to the sixth aspect, the controller calculates a first lift change amount, which is the difference between the first lift value of the first winch rope when the bucket device is in the fully open state and the first lift value of the first winch rope when the bucket device is in the fully closed state, and a second lift change amount, which is the difference between the second lift value of the second winch rope when the bucket device is in the fully open state and the second lift value of the second winch rope when the bucket device is in the fully closed state. If the first lift change amount is greater than the second lift change amount, the controller determines that the first winch rope is responsible for opening and closing the bucket device, and if the first lift change amount is less than the second lift change amount, the controller determines that the second winch rope is responsible for opening and closing the bucket device.

[0165] According to the sixth aspect, the rope responsible for opening and closing the bucket device can be determined from the first lifting value of the first winch rope and the second lifting value of the second winch rope when the bucket device is in a fully open state, and from the first lifting value of the first winch rope and the second lifting value of the second winch rope when the bucket device is in a fully closed state.

[0166] A construction machine equipped with a bucket control device according to the seventh aspect of the first technology comprises the first winch drum, the second winch drum, the bucket device, and a bucket control device according to any of the first to sixth aspects.

[0167] According to the seventh embodiment, a construction machine equipped with a bucket control device is provided, in which the open / closed state of the bucket device determined by the controller is notified to the operator, and the operator can grasp the status of the bucket device even in a work site where it is difficult to visually inspect the bucket device.

[0168] [Second Technology] Next, the second technology of this disclosure will be described. The second technology can be implemented in combination with the first technology described above. The second technology can also be implemented on its own without being combined with the first technology.

[0169] First, let me explain the problems that the second technology will solve.

[0170] [Second Technical Problem to be Solved] In the aforementioned Patent Documents 1 and 2, it is conceivable that an operation may be performed to further open the bucket device even though the bucket device is already open, or an operation may be performed to further close the bucket device even though the bucket device is already closed. In this case, excessive slack may occur in one of the winch ropes, which could lead to problems such as the rope becoming tangled or unruly.

[0171] The second technology of this disclosure was developed to solve the above-mentioned problems, and its purpose is to provide a bucket control device, a construction machine equipped with the bucket control device, and a bucket control method that can suppress malfunctions such as rope entanglement even when the bucket device is operated excessively in the opening direction or excessively in the closing direction.

[0172] A bucket control device according to the first aspect of the second technology is a control device for a construction machine comprising: a first winch drum for paying out and winding up a first winch rope; a second winch drum for paying out and winding up a second winch rope; a bucket device connected to the first and second winch ropes, which can be opened and closed and raised and lowered in accordance with the rotation of the first and second winch drums; a first winch operating device that provides an operation for rotating the first winch drum; and a second winch operating device that provides an operation for rotating the second winch drum. The bucket control device includes a controller that performs at least one of over-opening suppression control and over-closing suppression control. The over-opening suppression control is a control in which, when the bucket device is in an over-open state, being operated in the direction of further opening the bucket device from a predetermined open state, the controller stops paying out the rope from the opening / closing drum, which is one of the first and second winch drums responsible for opening and closing the bucket device. The over-closing suppression control is a control in which, when the bucket device is in an over-closed state, being operated in the direction of further closing the bucket device from a predetermined closed state, the controller stops winding up the rope from the opening / closing drum.

[0173] According to the first aspect of the second technology, when the bucket device is in an over-open state, the extension of the drum responsible for opening and closing the bucket device is stopped, and when the bucket device is in an over-closed state, the winding of the drum responsible for opening and closing the bucket device is stopped, thereby reducing slack in the winch rope and suppressing problems such as rope entanglement.

[0174] Preferred embodiments of the second technology of this disclosure will be described with reference to the drawings.

[0175] The second technology includes the following third and fourth embodiments. The third embodiment of the second technology can be implemented in combination with the first embodiment of the first technology described above, and can be implemented in combination with the second embodiment of the first technology described above. Similarly, the fourth embodiment of the second technology can be implemented in combination with the first embodiment of the first technology described above, and can be implemented in combination with the second embodiment of the first technology described above. However, the third embodiment of the second technology can also be implemented as the third embodiment alone, without being combined with either the first or second embodiment of the first technology. Similarly, the fourth embodiment of the second technology can also be implemented as the fourth embodiment alone, without being combined with either the first or second embodiment of the first technology.

[0176] [Third Embodiment] First, the third embodiment will be described in detail. The general outline of the crane 100 according to the third embodiment is as described with reference to Figures 1 to 4.

[0177] Figure 15 is a block diagram illustrating the main components of the control function of the controller 170 according to the third embodiment. The controller 170 controls the driving of the first winch WC1 and the second winch WC2 to open, close and raise and lower the bucket device 10. The controller 170 has a computer including a central processing unit (a processing unit such as a CPU) not shown in the figure, and a storage unit 78 consisting of ROM and RAM, and executes various processes including opening, closing and raising and lowering the bucket device 10. The controller 170 has a brake force adjustment unit 171, a drum operation control unit 172, an opening / closing state determination unit 173, an over-opening / closing suppression unit 174, a screen display control unit 175, a notification unit 176, a condition setting unit 177, a storage unit 178, and an opening / closing rope determination unit 179. These functions are realized when the processing unit executes a control program stored in the storage unit 178.

[0178] The controller 170 receives various command signals, including the first rotation amount nm of the first winch drum DR1 detected by the first rotation sensor 81, the second rotation amount na of the second winch drum DR2 detected by the second rotation sensor 82, an ON command signal that switches the control mode output from the non-synchronized control mode switch 90 to non-synchronized control mode, an ON command signal that switches the control mode output from the bucket assist mode switch 91 to bucket assist mode, and an ON command signal that activates the monitor 120 output from the monitor switch 92.

[0179] Furthermore, the controller 170 receives command signals corresponding to the operator's operations (operator operations in Figure 15). Specifically, the controller 170 receives command signals corresponding to the amount of lever operation by the operator output from the first winch operating device body 51B, command signals corresponding to the amount of lever operation by the operator output from the second winch operating device body 53B, command signals corresponding to the amount of brake operation by the operator output from the first brake operating device body 52B, and command signals corresponding to the amount of brake operation by the operator output from the second brake operating device body 54B (see Figure 2).

[0180] The controller 170 outputs command signals to various proportional valves (61A, 61B, 62, 63A, 63B, 64) calculated by the brake force adjustment unit 171 and the drum motion control unit 172, command signals related to the screen display of the monitor 120, and command signals to generate an alarm sound in the alarm device 126.

[0181] The brake force adjustment unit 171 adjusts the first brake force applied to the first winch drum DR1 and the second brake force applied to the second winch drum DR2. For example, when the control mode is set to synchronized control mode, a first brake operation that reduces the first brake force is applied to the first brake operation pedal 52A, and it is determined that the bucket device 10 is in an open state, the brake force adjustment unit 171 performs the following opening down control. In the opening down control, the first brake force and the second brake force are controlled so that the bucket device 10 descends by its own weight while maintaining the open state of the bucket device 10. Furthermore, when the control mode is set to synchronized control mode, a first brake operation that reduces the first brake force is applied to the first brake operation pedal 52A, and it is determined that the bucket device 10 is in a closed state, the brake force adjustment unit 171 performs the following closing down control. In the closing down control, the brake force adjustment unit 171 adjusts the first brake force and the second brake force so that the bucket device 10 descends while maintaining the closed state of the bucket device 10.

[0182] The drum operation control unit 172 controls the operation of the first winch drum DR1 and the second winch drum DR2. In the main auxiliary synchronization control in synchronization control mode, the operation of the first winch drum DR1 and the second winch drum DR2 are controlled based on the rotational operation given to the first winch operating device 51.

[0183] Specifically, the drum operation control unit 172 controls the operation of the first winch drum DR1 and the second winch drum DR2 so that, for example, when the control mode is set to synchronized control mode and a first unwinding operation is applied to the first winch operating lever 51A of the first winch operating device 51, the bucket device 10 descends while maintaining its open / closed state. Also, when the control mode is set to synchronized control mode and a first winding operation is applied to the first winch operating lever 51A of the first winch operating device 51, the drum operation control unit 172 controls the operation of the first winch drum DR1 and the second winch drum DR2 so that the bucket device 10 rises while maintaining its open / closed state.

[0184] [Over-opening / closing suppression control] The controller 170 performs over-opening / closing suppression control. The over-opening / closing suppression control includes over-opening suppression control and over-closing suppression control. The over-opening suppression control is a control in which the controller 170 stops paying out the rope from the opening / closing drum, which is the drum responsible for opening and closing the bucket device 10, among the first winch drum DR1 and the second winch drum DR1, when the bucket device 10 is in an over-open state, being operated in the direction to open the bucket device further from a predetermined open state. The over-closing suppression control is a control in which the controller 170 stops winding up the rope from the opening / closing drum when the bucket device 10 is in an over-closed state, being operated in the direction to close the bucket device further from a predetermined closed state. Specifically, it is as follows.

[0185] The opening / closing state determination unit 173 calculates the degree of opening / closing α of the bucket device 10 and determines the opening / closing state (degree of opening / closing) of the bucket device 10 from the calculated degree of opening / closing α. The opening / closing state determination unit 173 calculates the degree of opening / closing α from the following equation (1). In equation (1), ΔL is the difference between the first payout amount Lm of the first winch rope R1 and the second payout amount La of the second winch rope R2 (hereinafter, relative difference ΔL), and is calculated from the following equation (2). In the following explanation, the first payout amount Lm of the first winch rope R1 and the second payout amount La of the second winch rope R2 are considered positive when the bucket device 10 is being lowered (i.e., when the bucket device 10 is descending), and the signs of the first payout amount Lm and the second payout amount La are considered negative when the bucket device 10 is being raised (i.e., when the bucket device 10 is rising).

[0186] α=(ΔL-ΔLmin) / (ΔLmax-ΔLmin)×100...(1) ΔL=Lm-La...(2)

[0187] In equation (1), ΔLmax is the relative difference (hereinafter referred to as the maximum relative difference ΔLmax) between the amount Lm of the first winch rope R1 and the amount La of the second winch rope R2 when the bucket device 10 is fully open (hereinafter referred to as the fully open state). ΔLmin is the relative difference (hereinafter referred to as the minimum relative difference ΔLmin) between the amount Lm of the first winch rope R1 and the amount La of the second winch rope R2 when the bucket device 10 is fully closed (hereinafter referred to as the fully closed state). The maximum relative difference ΔLmax and the minimum relative difference ΔLmin are set in advance by the operator. The method for setting the maximum relative difference ΔLmax and the minimum relative difference ΔLmin will be described later. The fully open state is an example of a predetermined open state in this disclosure, and the fully closed state is an example of a predetermined closed state in this disclosure.

[0188] The opening / closing state determination unit 173 calculates the degree of opening / closing α of the bucket device 10 by applying the relative difference ΔL, which is calculated as it occurs, the maximum relative difference ΔLmax when the bucket device 10 is in a fully open state, and the minimum relative difference ΔLmin when the bucket device 10 is in a fully closed state, to equation (1). From equation (1), it is normalized so that when the relative difference ΔL is the maximum relative difference ΔLmax, the degree of opening / closing α is 100%, and when the relative difference ΔL is the minimum relative difference ΔLmin, the degree of opening / closing α is 0%.

[0189] Figure 16 shows the state of the bucket device 10 in the fully open and fully closed states. The right side of Figure 16 shows the fully open state, and the left side of Figure 16 shows the fully closed state. In the fully open state of the bucket device 10 shown in the right side of Figure 16, the first winch rope R1 is loose, and the bucket device 10 is supported by the second winch rope R2. At this time, the lower ends of the pair of buckets 13 of the bucket device 10 are furthest apart. As the first winch rope R1 is wound up from this state, the first winch rope R1 becomes taut, and as the first winch rope R1 is further wound up, the bucket device 10 is gradually closed. When the bucket device 10 is completely closed, it is in the state shown in the left side of Figure 16, where the first winch rope R1 is taut, while the second winch rope R2 is loose. At this time, the bucket device 10 is supported by the first winch rope R1, and the lower ends of the pair of buckets 13 of the bucket device 10 are adjacent to each other. The relative difference ΔL increases as the bucket device 10 transitions from a closed state to an open state, and the maximum relative difference ΔLmax in the fully open state becomes greater than the minimum relative difference ΔLmin in the fully closed state.

[0190] Here, the maximum relative difference ΔLmax is preferably set based on the state in which the bucket device 10 is fully open as shown in the right diagram of Figure 16 and there is almost no slack in the first winch rope R1. The minimum relative difference ΔLmin is preferably set based on the state in which the bucket device 10 is fully closed as shown in the left diagram of Figure 16 and there is almost no slack in the second winch rope R2. The maximum relative difference ΔLmax and the minimum relative difference ΔLmin are set in advance by the operator and then stored, for example, in a memory unit 178 built into the controller 170. Alternatively, the maximum relative difference ΔLmax and the minimum relative difference ΔLmin may be stored in a memory unit provided separately from the controller 170. Note that the maximum relative difference ΔLmax corresponds to the first reference value of this disclosure, and the minimum relative difference ΔLmin corresponds to the second reference value of this disclosure.

[0191] The first payout amount Lm of the first winch rope R1 is estimated from the following equation (3). In equation (3), Rm is the design effective radius of the first winch drum DR1. In equation (3), nm is the first rotation amount, which is the number of rotations of the first winch drum DR1 from a reference. In equation (3), once the effective radius Rm is set, the first payout amount Lm of the first winch rope R1 is calculated from the first rotation amount nm of the first winch drum DR1 detected by the first rotation sensor 81. Since the first payout amount Lm is calculated from the first rotation amount nm of the first winch drum DR1 detected by the first rotation sensor 81, the first rotation sensor 81 functions as a first detector for detecting the first payout amount in this disclosure.

[0192] Lm=Rm×nm...(3)

[0193] The second payout amount La of the second winch rope R2 is estimated from the following equation (4). In equation (4), Ra is the design effective radius of the second winch drum DR2. In equation (4), na is the second rotation amount, which is the number of rotations of the second winch drum DR2 from the reference. In equation (4), once the effective radius Ra is set, the second payout amount La of the second winch rope R2 is calculated from the second rotation amount na of the second winch drum DR2 detected by the second rotation sensor 82. Since the second payout amount La is calculated from the second rotation amount na of the second winch drum DR2 detected by the second rotation sensor 82, the second rotation sensor 82 functions as a second detector for detecting the second payout amount in this disclosure.

[0194] La=Ra×na...(4)

[0195] As a result, the first payout amount Lm of the first winch rope R1 calculated from equation (3) and the second payout amount La of the second winch rope R2 calculated from equation (4) are applied to equation (2) to calculate the relative difference ΔL. Furthermore, the degree of opening and closing α is calculated by applying the relative difference ΔL to equation (1).

[0196] Figure 17 shows an example of the change in the degree of opening / closing α of the bucket device 10 during operation, calculated by equation (1). In Figure 17, the horizontal axis represents time t [sec] and the vertical axis represents the degree of opening / closing α [%]. A degree of opening / closing α of 100% corresponds to the bucket device 10 being fully open and the relative difference ΔL being the preset maximum relative difference ΔLmax. A degree of opening / closing α of 0% corresponds to the bucket device 10 being fully closed and the relative difference ΔL being the preset minimum relative difference ΔLmin.

[0197] In Figure 17, as the bucket device 10 is opened, that is, as the first winch rope R1 is paid out, the first payout amount Lm increases, and the degree of opening / closing α increases toward 100%. When the degree of opening / closing α reaches 100%, the bucket device 10 is fully open, and the relative difference ΔL becomes the maximum relative difference ΔLmax. If the bucket device 10 is operated further in the opening direction from this state, that is, as the first winch rope R1 is paid out, the first winch rope R1 becomes excessively loose, as shown in the right-hand figure of Figure 18, resulting in an over-open state where the relative difference ΔL exceeds the maximum relative difference ΔLmax. The over-open state corresponds to the portion shown by the dashed line in Figure 17 where the degree of opening / closing α is greater than 100%.

[0198] Furthermore, as the bucket device 10 is closed, that is, as the first winch rope R1 is wound up, the first payout amount Lm decreases, and the degree of opening / closing α decreases toward 0%. When the degree of opening / closing α reaches 0%, the bucket device 10 is in a fully closed state, and the relative difference ΔL becomes the minimum relative difference ΔLmin. If the bucket device 10 is operated further in the closing direction from this state, that is, as the first winch rope R1 is wound up, the second winch rope R2 becomes excessively loose, as shown in the left diagram of Figure 18, resulting in an over-closed state where the relative difference ΔL becomes smaller than the minimum relative difference ΔLmin. The over-closed state corresponds to the portion shown by the dashed line in Figure 17 where the degree of opening / closing α is less than 0%.

[0199] In the over-open state described above, the first winch rope R1 becomes excessively loose, and in the over-closed state described above, the second winch rope R2 becomes excessively loose, which may cause the ropes to become tangled and unruly, which is undesirable. Although the over-open and over-closed states described above can be prevented by visually inspecting the bucket device 10, in some work sites, it may not be possible to visually inspect the bucket device 10 due to obstacles or other factors. In this case, the bucket device 10 may unintentionally become over-open or over-closed.

[0200] In contrast, the controller 170 is equipped with an over-opening / closing suppression unit 174. The over-opening / closing suppression unit 174 stops the payout of the ropes from the opening / closing drums, which are responsible for opening and closing the bucket device 10, among the first winch drum DR1 and the second winch drum DR2, when the bucket device 10 is in an over-open state, and stops the winding of the ropes from the opening / closing drums, which are responsible for opening and closing the bucket device 10, among the first winch drum DR1 and the second winch drum DR2.

[0201] In the third embodiment, the first winch drum DR1 is set as an opening / closing drum responsible for opening and closing the bucket device 10. As a result, the over-opening / closing suppression unit 174 stops paying out the first winch rope R1 from the first winch drum DR1 when the bucket device 10 is in an over-open state. Also, the over-opening / closing suppression unit 174 stops winding up the first winch rope R1 from the first winch drum DR1 when the bucket device 10 is in an over-closed state.

[0202] Furthermore, the open / closed state determination unit 173 has the function of determining whether the bucket device 10 is in an over-open state or an over-closed state. The open / closed state determination unit 173 makes the determination based on the relative difference ΔL, which is calculated as it occurs, the maximum relative difference ΔLmax, and the minimum relative difference ΔLmin. Specifically, if the relative difference ΔL is greater than the maximum relative difference ΔLmax, the open / closed state determination unit 173 determines that the bucket device 10 is in an over-open state, meaning it is being operated in the direction of opening the bucket device 10 further from an open state (fully open state). Also, if the relative difference ΔL is less than the minimum relative difference ΔLmin, the open / closed state determination unit 173 determines that the bucket device 10 is in an over-closed state, meaning it is being operated in the direction of closing the bucket device 10 further from a closed state (fully closed state).

[0203] When the over-opening / closing suppression unit 174 determines that the bucket device 10 is in an over-open state, it performs over-opening suppression control to stop the rotation of the first winch drum DR1 in the unwinding direction. Specifically, the over-opening / closing suppression unit 174 controls the pilot pressure of the first unwinding proportional valve 61A and the secondary pressure (pilot pressure) of the first winding proportional valve 61B, and provides an output to the first winch drum DR1 that stops its rotation. For example, the over-opening / closing suppression unit 174 may control the pilot pressure of the first unwinding proportional valve 61A and the pilot pressure of the first winding proportional valve 61B to zero, and switch the first control valve 32 to the neutral position, thereby stopping the rotation of the first winch drum DR1 in the unwinding direction.

[0204] Furthermore, if the over-opening / closing suppression unit 174 determines that the bucket device 10 is in an over-closed state, it performs over-closing suppression control to stop the rotation of the first winch drum DR1 in the winding direction. Specifically, the over-opening / closing suppression unit 174 controls the pilot pressure of the first pay-out proportional valve 61A and the secondary pressure (pilot pressure) of the first winding proportional valve 61B to provide an output to the first winch drum DR1 that stops its rotation. For example, the over-opening / closing suppression unit 174 may control the pilot pressure of the first pay-out proportional valve 61A and the pilot pressure of the first winding proportional valve 61B to zero and switch the first control valve 32 to the neutral position to stop the rotation of the first winch drum DR1 in the winding direction.

[0205] As described above, if the bucket device 10 is determined to be in an over-open state, the over-opening / closing suppression unit 174 performs over-opening suppression control, stopping the rotation of the first winch drum DR1 and stopping the payout of the first winch rope R1. As a result, as shown by the solid line in Figure 17, the degree of opening / closing α is prevented from becoming greater than 100%, and the first winch rope R1 is prevented from becoming excessively loose. Similarly, if the bucket device 10 is determined to be in an over-closed state, the over-opening / closing suppression unit 174 performs over-closed suppression control, stopping the rotation of the first winch drum DR1 and stopping the winding of the first winch rope R1. As a result, as shown by the solid line in Figure 17, the degree of opening / closing α is prevented from becoming less than 0%, and the second winch rope R2 is prevented from becoming excessively loose.

[0206] When the opening / closing state determination unit 173 determines that the bucket device 10 is in an over-open or over-closed state, the notification unit 176 activates the alarm device 126, which generates a buzzer sound or voice message. This notifies the operator that the bucket device 10 is in an over-open or over-closed state and prompts the operator to stop operating the bucket device 10 in the opening or closing direction. Furthermore, when the bucket device 10 is determined to be in an over-open or over-closed state, the notification unit 176 may display this on the monitor 120 and prompt the operator to stop operating the bucket device 10 in the opening or closing direction.

[0207] Figure 19 is a flowchart illustrating the control operation of the controller 170, which prevents the bucket device 10 from moving further in the opening direction when it is determined to be in an over-open state, and prevents the bucket device 10 from moving further in the closing direction when it is determined to be in an over-closed state. This flowchart is executed repeatedly while the crane 100 is in operation.

[0208] First, the controller 170 stores the maximum relative difference ΔLmax and minimum relative difference ΔLmin set by the operator in the storage unit 178 (step S310). Next, the controller 170 calculates the current relative difference ΔL from equation (2) (step S320). Then, the controller 170 determines whether the relative difference ΔL calculated in step S320 is greater than the maximum relative difference ΔLmax (step S330).

[0209] If the relative difference ΔL is greater than the maximum relative difference ΔLmax (YES in step S330), the controller 170 provides an output to the first payout proportional valve 61A and the first retraction proportional valve 61B to prevent the first winch drum DR1 from rotating in the payout direction (step S340). This prevents the first winch drum DR1 from rotating in the payout direction. In this case, output in the retraction direction of the first winch drum DR1 may be permitted.

[0210] On the other hand, in step S330, if the relative difference ΔL is less than or equal to the maximum relative difference ΔLmax (NO in step S330), the controller 170 determines whether the relative difference ΔL is less than the minimum relative difference ΔLmin (step S350).

[0211] If the relative difference ΔL is less than the minimum relative difference ΔLmin (YES in step S350), the controller 170 provides an output to the first pay-out proportional valve 61A and the first rewind proportional valve 61B to prevent the first winch drum DR1 from rotating in the rewinding direction (step S360). This prevents the first winch drum DR1 from rotating in the rewinding direction. In this case, output in the pay-out direction of the first winch drum DR1 may be permitted. If, in step S350, the relative difference ΔL is greater than or equal to the minimum relative difference ΔLmin (NO in step S350), the controller 170 terminates control.

[0212] [Setting Conditions] Next, the method for setting the maximum relative difference ΔLmax and the minimum relative difference ΔLmin will be described. The controller 170 is equipped with a condition setting unit 177 for setting the maximum relative difference ΔLmax and the minimum relative difference ΔLmin.

[0213] When the condition setting unit 177 receives an ON command signal from the monitor switch 92, for example, to activate the monitor 120, it starts setting the maximum relative difference ΔLmax and the minimum relative difference ΔLmin. The condition setting unit 177 outputs a command to the screen display control unit 175 to start setting the maximum relative difference ΔLmax when the bucket device 10 is at a predetermined lifting height. Upon receiving the above command, the screen display control unit 175 displays an image on the monitor 120 as shown in the left diagram of Figure 20.

[0214] The left diagram in Figure 20 is an example of an image displayed on the monitor 120 when setting the maximum relative difference ΔLmax. At the bottom of the monitor 120, text is displayed instructing the user to open the bucket device 10 to the extent that the first winch rope R1 and the second winch rope R2 do not slacken (to the fully open state). On the left side of the monitor 120, an image diagram is displayed showing a preferred example (right side) and an unpredictable example (left side) of the bucket device 10 being fully open. The preferred example is when the bucket device 10 is fully open and the first winch rope R1 and the second winch rope R2 are not slack. The unpredictable example is when the bucket device 10 is fully open and the first winch rope R1 is slack. The left diagram in Figure 20 also shows the OK button 122, which is selected when the adjustment of the bucket device 10 is complete, and the BACK button 124, which returns to the previous setting.

[0215] The operator operates the first winch operating lever 51A of the first winch operating device 51 and the second winch operating lever 53A of the second winch operating device 53 in accordance with the display on the monitor 120, so that the bucket device 10 is fully open. When the operator confirms that the bucket device 10 is fully open with the first winch rope R1 and the second winch rope R2 not slackening, the operator selects the OK button 122. When the OK button 122 is selected, the condition setting unit 177 obtains the first payout amount Lm of the first winch rope R1 and the second payout amount La of the second winch rope R2 in this state and calculates the relative difference ΔL from equation (2). Next, the condition setting unit 177 sets the calculated relative difference ΔL as the maximum relative difference ΔLmax and stores the set maximum relative difference ΔLmax in the storage unit 178.

[0216] Next, the condition setting unit 177 starts setting the minimum relative difference ΔLmin. The condition setting unit 177 outputs a command to the screen display control unit 175 to start setting the minimum relative difference ΔLmin when the bucket device 10 is at a predetermined lifting height. Upon receiving the above command, the screen display control unit 175 displays an image on the monitor 120 as shown in the right-hand figure of Figure 20.

[0217] The right-hand diagram in Figure 20 shows an example of an image displayed on the monitor 120 when setting the minimum relative difference ΔLmin. At the bottom of the monitor 120, text instructions are displayed indicating that the bucket device 10 should be closed (fully closed) to the extent that the first winch rope R1 and the second winch rope R2 do not loosen. On the left side of the monitor 120, an image diagram shows a preferred example (right) and an unpredictable example (left) of the bucket device 10 being fully closed. The preferred example is when the bucket device 10 is fully closed and the first winch rope R1 and the second winch rope R2 are not loose. The unpredictable example is when the bucket device 10 is fully closed and the second winch rope R2 is loose. Also, the right-hand diagram in Figure 20 shows the OK button 122, which is selected when the adjustment of the bucket device 10 is complete, and the BACK button 124, which returns to the previous setting, side by side.

[0218] The operator operates the first winch operating lever 51A and the second winch operating lever 53A according to the display on the monitor 120 so that the bucket device 10 is fully closed. When the operator confirms that the bucket device 10 is fully closed with the first winch rope R1 and the second winch rope R2 not slackening, the operator selects the OK button 122. When the OK button 122 is selected, the condition setting unit 177 obtains the first payout amount Lm of the first winch rope R1 and the second payout amount La of the second winch rope R2 in this state and calculates the relative difference ΔL from equation (2). Next, the condition setting unit 177 sets the calculated relative difference ΔL as the minimum relative difference ΔLmin and stores the set minimum relative difference ΔLmin in the storage unit 178.

[0219] Incidentally, the winding layers of the first winch rope R1 in the first winch drum DR1 change according to the first rotation amount nm of the first winch rope R1. In connection with this, the actual effective radius Rm of the first winch drum DR1 changes according to the first rotation amount nm. As a result, there is an error Δrm in the effective radius Rm of the first winch drum DR1. The effective radius Rmer considering the above error Δrm is shown by equation (5) below. For similar reasons, there is also an error Δra in the effective radius Ra of the second winch drum DR2. The effective radius Raer considering the above error Δra is shown by equation (6) below.

[0220] Rmer=Rm+Δrm...(5) Raer=Ra+Δra...(6)

[0221] To reduce the effects of these errors Δrm and Δra, the maximum relative difference ΔLmax and minimum relative difference ΔLmin, taking into account the above errors Δrm and Δra, are determined as follows.

[0222] The maximum relative difference ΔLmax is set as the average of the maximum relative difference ΔLmax(Hhigh) set when the bucket device 10 is at its highest lifting height Hhigh and the maximum relative difference ΔLmax(Hlow) set when the bucket device 10 is at its lowest lifting height Hlow. Specifically, the maximum relative difference ΔLmax is calculated from the following equation (7). The minimum relative difference ΔLmin is set as the average of the minimum relative difference ΔLmin(Hhigh) set when the bucket device 10 is at its highest lifting height Hhigh and the minimum relative difference ΔLmin(Hlow) set when the bucket device 10 is at its lowest lifting height Hlow. Specifically, the minimum relative difference ΔLmin is calculated from the following equation (8).

[0223] ΔLmax=(ΔLmax(Hhigh)+ΔLmax(Hlow)) / 2...(7) ΔLmin=(ΔLmin(Hhigh)+ΔLmin(Hlow)) / 2...(8)

[0224] Figure 21 shows the bucket device 10 at its maximum lift height Hhigh and at its minimum lift height Hlow. The maximum lift height Hhigh is the highest position the bucket device 10 can take. That is, the maximum lift height Hhigh is the value at which the rotation amounts nm and na of each winch drum DR1 and DR2 are minimized, and the distance between the bucket device 10 and the ground G is maximized. The minimum lift height Hlow is the lowest position the bucket device 10 can take from the ground G. That is, the minimum lift height Hlow is the position at which the rotation amounts nm and na of each winch drum DR1 and DR2 are maximized within the range where the bucket device 10 is away from the ground G. In addition, when defining the maximum lifting height Hhigh and minimum lifting height Hlow of the bucket device 10, the angle θ of the luffing member 104 with respect to the horizontal line (boom angle θ) may be predetermined as a reference angle (for example, 45 degrees).

[0225] As described above, by setting the maximum relative difference ΔLmax and the minimum relative difference ΔLmin to the average of the values ​​set for the maximum head Hhigh and the minimum head Hlow, the influence of errors Δrm and Δra can be reduced.

[0226] When setting the maximum relative difference ΔLmax and the minimum relative difference ΔLmin, the condition setting unit 177 outputs a command to prompt the operator to move the bucket device 10 to, for example, the maximum lifting height Hhigh. Specifically, the condition setting unit 177 issues a command to the screen display control unit 175 to display an instruction on the monitor 120 to move the bucket device 10 to the maximum lifting height Hhigh.

[0227] The screen display control unit 175 receives the above command from the condition setting unit 177 and displays an image on the monitor 120 as shown in the left diagram of Figure 22. In the upper right corner of the monitor 120, the instruction to raise the bucket device 10, that is, to move the bucket device 10 to the maximum lifting height Hhigh, is displayed in text. Also, on the left side of the monitor 120, a simplified diagram illustrating the above instruction is displayed. Furthermore, the monitor 120 displays an OK button 122 to be selected when the adjustment of the position of the bucket device 10 is complete, and a BACK button 124 to return to the previous setting.

[0228] The operator raises the bucket device 10 to the maximum lift height Hhigh according to the display on the monitor 120, and then selects the OK button 122. After the OK button 122 is selected, the condition setting unit 177 sets the maximum relative difference ΔLmax(Hhigh) and the minimum relative difference ΔLmin(Hhigh) at the maximum lift height Hhigh.

[0229] Next, the condition setting unit 177 outputs a command to prompt the operator to move the bucket device 10 to the lowest lift height Hlow. Specifically, the condition setting unit 177 issues a command to the screen display control unit 175 to display on the monitor 120 an instruction for the operator to move the bucket device 10 to the lowest lift height Hlow.

[0230] The screen display control unit 175 receives the above command from the condition setting unit 177 and displays an image on the monitor 120 as shown in the right-hand diagram of Figure 22. In the upper right corner of the monitor 120, a text instruction is displayed to lower the bucket device 10, that is, to move the bucket device 10 to the lowest lifting height, Hlow. Also, on the left side of the monitor 120, a simplified diagram illustrating the above instruction is displayed. Furthermore, the monitor 120 displays an OK button 122 to be selected when the adjustment of the position of the bucket device 10 is complete, and a BACK button 124 to return to the previous setting.

[0231] The operator lowers the bucket device 10 to the minimum lift height Hlow according to the display on the monitor 120, and then selects the OK button 122. After the OK button 122 is selected, the condition setting unit 177 sets the maximum relative difference ΔLmax(Hlow) and the minimum relative difference ΔLmin(Hlow) at the minimum lift height Hlow.

[0232] By performing the above operations, the maximum relative difference ΔLmax(Hhigh) and minimum relative difference ΔLmin(Hhigh) at the highest head height Hhigh, and the maximum relative difference ΔLmax(Hlow) and minimum relative difference ΔLmin(Hlow) at the lowest head height Hlow are obtained. Then, the condition setting unit 177 calculates the maximum relative difference ΔLmax and minimum relative difference ΔLmin from equations (7) and (8), taking into account the errors Δrm and Δra. When calculating the degree of opening / closing α, the use of the above maximum relative difference ΔLmax and minimum relative difference ΔLmin reduces the influence of the errors Δrm and Δra.

[0233] [Determination of the rope responsible for opening and closing] The controller 170 also includes an opening / closing rope determination unit 179 that determines whether the winch rope responsible for opening and closing the bucket device 10 is the first winch rope R1 or the second winch rope R2. The opening / closing rope determination unit 179 has the function of determining whether the rope responsible for opening and closing the bucket device 10 is the first winch rope R1 (main winding rope) or the second winch rope R2 (auxiliary winding rope). Depending on how the winch ropes R1 and R2 are connected to the bucket device 10, the first winch rope R1 (main winding rope) may become the rope responsible for opening and closing the bucket device 10, or the second winch rope R2 (auxiliary winding rope) may become the rope responsible for opening and closing the bucket device 10. For example, it is possible that the rope responsible for opening and closing the bucket device 10 may be different from the rope intended by the operator. Therefore, the opening / closing rope determination unit 179 determines the rope responsible for opening and closing the bucket device 10 in accordance with the settings of the maximum relative difference ΔLmax and minimum relative difference ΔLmin described above.

[0234] The opening / closing rope determination unit 179 calculates the first change amount ΔLm and the second change amount ΔLa without changing the lifting height of the bucket device 10. Specifically, the opening / closing rope determination unit 179 calculates, for example, the first change amount ΔLm of the first payout amount Lm of the first winch rope R1 and the second change amount ΔLa of the second payout amount La of the second winch rope R2 when the bucket device 10 is at its lowest lifting height Hlow. The first change amount ΔLm is calculated from the following equation (9). In equation (9), Lmopn is the first payout amount Lm when the bucket device 10 is in the fully open state, and Lmcls is the first payout amount Lm when the bucket device 10 is in the fully closed state. The second change amount ΔLa is calculated from the following equation (10). In equation (10), Laopn is the second payout amount La when the bucket device 10 is fully open, and Lacls is the second payout amount La when the bucket device 10 is fully closed. From equation (9), the first change amount ΔLm is the difference between the first payout amount Lmopn of the first winch rope R1 when the bucket device 10 is fully open and the first payout amount Lmcls of the first winch rope R1 when the bucket device 10 is fully closed. Also, from equation (10), the second change amount ΔLa is the difference between the second payout amount Laopn of the second winch rope R2 when the bucket device 10 is fully open and the second payout amount Lacls when the bucket device 10 is fully closed.

[0235] ΔLm=Lmopn-Lmcls...(9) ΔLa=Laopn-Lacls...(10)

[0236] The opening / closing rope determination unit 179 calculates the first change amount ΔLm and the second change amount ΔLa, and then determines whether the calculated first change amount ΔLm is greater than the second change amount ΔLa. If the first change amount ΔLm is greater than the second change amount ΔLa, the opening / closing rope determination unit 179 determines that the first winch rope R1 is responsible for opening and closing the bucket device 10, and the second winch rope R2 is responsible for supporting the bucket device 10. On the other hand, if the first change amount ΔLm is less than the second change amount ΔLa, the unit determines that the second winch rope R2 is responsible for opening and closing, and the first winch rope R1 is responsible for supporting the bucket device 10.

[0237] Figure 23 is a flowchart illustrating the control operations performed by the opening / closing rope determination unit 179 when determining the rope responsible for opening and closing the bucket device 10. The flowchart in Figure 23 is performed when setting initial conditions, for example, when the bucket device 10 is at its lowest lifting height, Hlow.

[0238] First, the opening / closing rope determination unit 179 calculates the change in the first payout amount Lm of the first winch rope R1 ΔLm from the first payout amount Lmopn of the first winch rope R1 when the bucket device 10 is fully open and the first payout amount Lmcls of the first winch rope R1 when the bucket device 10 is fully closed (step S410). Next, the opening / closing rope determination unit 179 calculates the change in the second payout amount La of the second winch rope R2 ΔLa from the second payout amount Laopn of the second winch rope R2 when the bucket device 10 is fully open and the second payout amount Lacls of the second winch rope R2 when the bucket device 10 is fully closed (step S420). Next, the opening / closing rope determination unit 179 determines whether the change in ΔLm calculated in step S410 is greater than the change in ΔLa calculated in step S420 (step S430). If the change amount ΔLm is greater than the change amount ΔLa (Yes in step S430), the opening / closing rope determination unit 179 determines that the first winch rope R1 is the rope responsible for opening and closing the bucket device 10 (step S440). On the other hand, if the change amount ΔLm is less than the change amount ΔLa (No in step S430), the opening / closing rope determination unit 179 determines that the second winch rope R2 is the rope responsible for opening and closing the bucket device 10 (step S450).

[0239] Based on the flowchart in Figure 23, for example, if the first winch rope R1 is determined to be the rope responsible for opening and closing the bucket device 10, the opening / closing rope determination unit 179 issues a command to the screen display control unit 175 to display an image as shown in Figure 24 on the monitor 120 in order to confirm whether this determination is what the operator intended. The screen display control unit 175 displays an image as shown in Figure 24 on the monitor 120 in accordance with the above command. If the rope responsible for opening and closing the bucket device 10 is determined to be the first winch rope R1, the connection destination of the rope responsible for opening and closing will be displayed as "main winding (first winch rope R1)" as shown in Figure 24. On the other hand, if the rope responsible for opening and closing the bucket device 10 is determined to be the second winch rope R2, the connection destination of the rope responsible for opening and closing will be displayed as "auxiliary winding (second winch rope R2)".

[0240] If the display on the monitor 120 matches the operator's intention, the operator selects the OK button 122. On the other hand, if the display on the monitor 120 differs from the operator's intention, the operator selects the BACK button 124 and reconfirms the rope connection destination. This operation prevents the operator from using the wrong rope to open and close the bucket device 10.

[0241] [Fourth Embodiment] Next, a fourth embodiment of the second technology will be described.

[0242] In the third embodiment described above, the degree of opening / closing α of the bucket device 10 was calculated using the relative difference ΔL (= Lm - La) between the first payout amount Lm and the second payout amount La. In the fourth embodiment, instead, the opening / closing state determination unit 173 may calculate the degree of opening / closing α using the difference in lifting values ​​ΔLF (= ΔLFm - ΔLFa), which is the difference between the lifting value of the first winch rope R1 (first lifting value LFm) and the lifting value of the second winch rope R2 (second lifting value LFa).

[0243] The lifting height value LF referred to here is different from the lifting height of the bucket device 10 (height from the ground G), and corresponds to the change in lifting height based on a specific state. For example, a specific state may be set to a state where the first winch drum DR1 is at 0 rotations, the second winch drum DR2 is at 0 rotations, and the luffing member angle θ (boom angle θ) of the luffing member 104 with respect to the horizontal line is 45 degrees. The state of "first winch drum DR1 at 0 rotations" is the state in which the first winch rope R1 is fully extended from the first winch drum DR1. The state of "second winch drum DR2 at 0 rotations" is the state in which the second winch rope R2 is fully extended from the second winch drum DR2. When the lifting height value of the first winch rope R1 in this specific state is taken as the reference (zero), the first lifting height value LFm is the change in lifting height from that reference. Similarly, when the lifting height of the second winch rope R2 in the aforementioned specific state is taken as the baseline (zero), the second lifting height LFa is the amount of change in the lifting height from that baseline.

[0244] The controller 170 can calculate the first lifting height LFm of the first winch rope R1 based on the amount of rotation nm of the first winch drum DR1 detected by the first rotation sensor 81 and the luffing member angle θ detected by the luffing member angle detector 83 (see Figure 21). Similarly, the controller 170 can calculate the second lifting height LFa of the second winch rope R2 based on the amount of rotation na of the second winch drum DR2 detected by the second rotation sensor 82 and the luffing member angle θ. Specifically, it is as follows.

[0245] The first lifting height value LFm of the first winch rope R1 changes not only according to the amount of the first winch rope R1 unfurled from the first winch drum DR1, but also according to the luffing member angle θ of the luffing member 104. Similarly, the second lifting height value LFa of the second winch rope R2 changes not only according to the amount of the second winch rope R2 unfurled from the second winch drum DR2, but also according to the luffing member angle θ of the luffing member 104.

[0246] The controller 170 may pre-store specification data including the length of the luffing member 104, data relating to the relative position of the first winch drum DR1 with respect to a specific part of the luffing member 104 (for example, the base end of the luffing member 104), and data relating to the relative position of the second winch drum DR2 with respect to the specific part of the luffing member 104. In this case, the controller 170 can calculate a first distance and a second distance that change according to the luffing member angle θ from the geometric positional relationship of the luffing member 104, the first winch drum DR1, and the second winch drum DR2. The first distance is the distance from the first winch drum DR1 to a predetermined first part of the luffing member 104 (for example, the upper end of the luffing member 104). The second distance is the distance from the second winch drum DR2 to a predetermined second part of the luffing member 104 (for example, the upper end of the luffing member 104). Furthermore, the controller 170 may pre-store a relational expression representing the relationship between the luffing member angle θ and the first distance, and a relational expression representing the relationship between the luffing member angle θ and the second distance. In this case, the controller 170 may calculate the first distance and the second distance using the luffing member angle θ detected by the luffing member angle detector 83 and the two relational expressions described above.

[0247] The controller 170 uses information such as specification data including the length of the luffing member 104, data regarding the relative position of the first winch drum DR1 with respect to the specific part of the luffing member 104, and data regarding the relative position of the second winch drum DR2 with respect to the specific part of the luffing member 104, as well as detection results input to the controller 170 from the rotation sensors 81 and 82, and the luffing member angle θ of the luffing member 104 input to the controller 170 from the luffing member angle detector 83, to calculate the first lifting height value LFm of the first winch rope R1 and the second lifting height value LFa of the second winch rope R2, respectively.

[0248] Specifically, for example, the controller 170 may calculate the first lifting height value LFm of the first winch rope R1 based on the change in the first distance ΔL1 for the specific state, the change in the height position of the upper end of the luffing member 104 ΔH1 for the specific state, and the change in the amount of the first winch rope R1 extended ΔR1 for the specific state. The controller 170 may also calculate the first lifting height value LFm of the first winch rope R1 using, for example, the following equation (11).

[0249] LFm=-(ΔL1+ΔH1+ΔR1)...(11)

[0250] Similarly, the controller 170 may calculate the second lifting height LFa of the second winch rope R2 based on the change in the second distance ΔL2 for the specific state, the change in the height position of the upper end of the luffing member 104 ΔH2 for the specific state, and the change in the amount of the second winch rope R2 extended ΔR2 for the specific state. The controller 170 may calculate the second lifting height LFa of the second winch rope R2 using, for example, the following equation (12).

[0251] LFa=-(ΔL2+ΔH2+ΔR2)...(12)

[0252] In the fourth embodiment, the opening / closing state determination unit 173 calculates the degree of opening / closing α using the following equation (13). In equation (13), the maximum lifting height difference ΔLFmax and the minimum lifting height difference ΔLFmin are preset values. The maximum lifting height difference ΔLFmax is the lifting height difference between the first lifting height value LFm of the first winch rope R1 and the second lifting height value LFa of the second winch rope R2 when the bucket device 10 is in the fully open state, and is preset in the same way as the maximum relative difference ΔLmax described above. The minimum lifting height difference ΔLFmin is the lifting height difference between the first lifting height value LFm of the first winch rope R1 and the second lifting height value LFa of the second winch rope R2 when the bucket device 10 is in the fully closed state, and is preset in the same way as the minimum relative difference ΔLmin described above. The opening / closing state determination unit 173 calculates the degree of opening / closing α of the bucket device 10 by applying the lifting height difference ΔLF, the maximum lifting height difference ΔLFmax, and the minimum lifting height difference ΔLFmin, which are calculated as needed, to equation (13). The maximum lifting height difference ΔLFmax corresponds to the first lifting height reference value of this disclosure, and the minimum lifting height difference ΔLFmin corresponds to the second lifting height reference value of this disclosure.

[0253] α=(ΔLF-ΔLFmin) / (ΔLFmax-ΔLFmin)×100...(13)

[0254] Furthermore, in order to improve the calculation accuracy of the degree of opening α, the maximum head value difference ΔLFmax may be the average of the maximum head value difference ΔLFmax(Hhigh) set when the head of the bucket device 10 is at the highest head height Hhigh and the minimum head value difference ΔLFmin(Hlow) set when the head of the bucket device 10 is at the lowest head height Hlow. Similarly, the minimum head value difference ΔLFmin may be the average of the minimum head value difference ΔLFmin(Hhigh) set when the head of the bucket device 10 is at the highest head height Hhigh and the minimum head value difference ΔLFmin(Hlow) set when the head of the bucket device 10 is at the lowest head height Hlow. This further improves the calculation accuracy of the degree of opening α.

[0255] Furthermore, the opening / closing state determination unit 173 determines whether the bucket device 10 is in an over-open state or an over-closed state based on the lifting height difference ΔLF, the maximum lifting height difference ΔLFmax, and the minimum lifting height difference ΔLFmin. Specifically, the opening / closing state determination unit 173 determines that the bucket device 10 is in an over-open state if the lifting height difference ΔLF is greater than the maximum lifting height difference ΔLFmax, and determines that the bucket device 10 is in an over-closed state if the lifting height difference ΔLF is less than the minimum lifting height difference ΔLFmin.

[0256] Furthermore, the opening / closing rope determination unit 179 can determine which of the first winch rope R1 and the second winch rope R2 is responsible for opening and closing the bucket device 10, based on the first lifting height value LFm of the first winch rope R1 and the second lifting height value LFa of the second winch rope R2.

[0257] Specifically, the opening / closing rope determination unit 179 calculates a first lift change amount ΔLFm, which is the difference (=LFmopn - LFmcls) between the first lift value LFmopn of the first winch rope R1 when the bucket device 10 is in a fully open state and the first lift value LFmcls of the first winch rope R1 when the bucket device 10 is in a fully closed state. Furthermore, the opening / closing rope determination unit 179 calculates a second lift change amount ΔLFa, which is the difference (=LFaopn - LFacls) between the second lift value LFaopn of the second winch rope R2 when the bucket device 10 is in a fully open state and the second lift value LFacls of the second winch rope R2 when the bucket device 10 is in a fully closed state. The opening / closing rope determination unit 179 determines that the first winch rope R1 is responsible for opening and closing the bucket device 10 if the calculated first lifting height change amount ΔLFm is greater than the second lifting height change amount ΔLFa. Furthermore, the opening / closing rope determination unit 179 determines that the second winch rope R2 is responsible for opening and closing the bucket device 10 if the calculated first lifting height change amount ΔLFm is less than the second lifting height change amount ΔLFa. In this way, the bucket device 10 can be over-opened and over-closed, and the rope responsible for opening and closing the bucket device 10 can be determined based on the first lifting height value LFm of the first winch rope R1 and the second lifting height value LFa of the second winch rope R2, thus achieving the same operation and effects as in the third embodiment.

[0258] [Modifications] In the third and fourth embodiments described above, the final maximum relative difference ΔLmax and minimum relative difference ΔLmin were determined from the average values ​​of the maximum relative difference ΔLmax and minimum relative difference ΔLmin when the bucket device 10 is at its highest lifting height Hhigh and when the bucket device 10 is at its lowest lifting height Hlow, but the present disclosure is not limited thereto. For example, the maximum relative difference ΔLmax (Hhigh) and minimum relative difference ΔLmin (Hhigh) may be set based on the bucket device 10 being at a predetermined lifting height. Similarly, the maximum lifting value difference ΔLFmax and minimum lifting value difference ΔLFmin may also be set based on the bucket device 10 being at a predetermined lifting height.

[0259] In the third and fourth embodiments described above, the rotation of the first winch drum DR1 was stopped based on the pilot pressure output from the first dispensing proportional valve 61A and the pilot pressure output from the first winding proportional valve 61B. However, this disclosure is not limited to the above configuration. For example, the rotation of the first winch drum DR1 may be stopped based on the pilot pressure output from one proportional valve. Similarly, the rotation of the second winch drum DR2 may be stopped based on the pilot pressure output from one proportional valve. In other words, the structure of the first stopping device for stopping the rotation of the first winch drum DR1 and the second stopping device for stopping the rotation of the second winch drum DR2 may be modified as appropriate.

[0260] In the third and fourth embodiments described above, the bucket device 10 was mounted on a crane 100 as a construction machine, but this disclosure is not limited to cranes and can be any construction machine on which a bucket device is mounted.

[0261] In the third and fourth embodiments described above, the storage unit 178 was built into the controller 170, but the storage unit 178 may be arranged separately from the controller 170.

[0262] In the third and fourth embodiments described above, the control mode of the bucket device 10 was configured to be switchable between assist mode, non-assist mode, synchronized control mode, and non-synchronized control mode. However, this disclosure is not limited to embodiments that include the above control modes. That is, this disclosure is also applicable to conventional cranes that do not have the above control modes.

[0263] In the third and fourth embodiments described above, the bucket control device is provided on the crane 100. However, the bucket control device in this disclosure does not necessarily have to be provided on a construction machine such as the crane 100, and may be located at a location away from the construction machine. In this case, the bucket control device is configured to be able to send and receive information between the bucket control device and the construction machine via a network such as the internet or a mobile phone network.

[0264] In the third and fourth embodiments described above, the luffing member 104 shown in Figure 1 is a boom having a lattice structure (lattice boom), but the luffing member may include a boom having a lattice structure and a jib having a lattice structure, or it may be an extendable boom (telescopic boom). The construction machine may be placed on the ground, on a structure, or on a ship. In any of these cases, the lower body of the construction machine may have a crawler running device as shown in Figure 1, a running device including tires, or it may be composed of a structure such as a support platform that cannot move on its own.

[0265] In the third and fourth embodiments described above, both over-opening suppression control and over-closing suppression control were performed, but the present disclosure is not limited thereto. That is, the controller 170 may perform over-opening suppression control but not over-closing suppression control, or vice versa.

[0266] As described above, according to the second technology, including the third and fourth embodiments of this disclosure, it is possible to provide a bucket control device and a construction machine equipped with the bucket control device that can suppress the bucket device from becoming over-opened or over-closed even if the bucket device is over-opened or over-closed. The second technology of this disclosure includes the following first to eleventh embodiments.

[0267] A bucket control device according to the first aspect of the second technology is a control device for a construction machine comprising: a first winch drum for paying out and winding up a first winch rope; a second winch drum for paying out and winding up a second winch rope; a bucket device connected to the first and second winch ropes, which can be opened and closed and raised and lowered in accordance with the rotation of the first and second winch drums; a first winch operating device that provides an operation for rotating the first winch drum; and a second winch operating device that provides an operation for rotating the second winch drum. The bucket control device includes a controller that performs at least one of over-opening suppression control and over-closing suppression control. The over-opening suppression control is a control in which, when the bucket device is in an over-open state, being operated in the direction of further opening the bucket device from a predetermined open state, the controller stops paying out the rope from the opening / closing drum, which is one of the first and second winch drums responsible for opening and closing the bucket device. The over-closing suppression control is a control in which, when the bucket device is in an over-closed state, being operated in the direction of further closing the bucket device from a predetermined closed state, the controller stops winding up the rope from the opening / closing drum.

[0268] According to the first embodiment, when the bucket device is in an over-open state, the extension of the drum responsible for opening and closing the bucket device is stopped, and when the bucket device is in an over-closed state, the winding of the drum responsible for opening and closing the bucket device is stopped, thereby reducing slack in the winch rope and suppressing problems such as rope entanglement.

[0269] A bucket control device according to a second embodiment of the second technology preferably further comprises the following features in addition to the bucket control device according to the first embodiment. That is, in the second embodiment, the construction machine comprises a first detector for detecting a first payout amount, which is the amount of the first winch rope paid out, or a first lifting value, which is the lifting value of the first winch rope; a second detector for detecting a second payout amount, which is the amount of the second winch rope paid out, or a second lifting value, which is the lifting value of the second winch rope; and a storage unit. The storage unit pre-stores a first reference value which is the difference between the amount of the first winch rope unwound and the amount of the second winch rope unwound when the bucket device is in the predetermined open state, and a second reference value which is the difference between the amount of the first winch rope unwound and the amount of the second winch rope unwound when the bucket device is in the predetermined closed state. Alternatively, the storage unit pre-stores a first lifting reference value which is the difference between the lifting height of the first winch rope and the lifting height of the second winch rope when the bucket device is in the predetermined open state, and a second lifting reference value which is the difference between the lifting height of the first winch rope and the lifting height of the second winch rope when the bucket device is in the predetermined closed state. The controller determines whether the bucket device is in either the over-open state or the over-closed state based on the relative difference which is the difference between the first payout amount and the second payout amount, the first reference value, and the second reference value. Alternatively, the controller determines whether the bucket device is in either the over-open state or the over-closed state based on the difference in lift values ​​which is the difference between the first lift value and the second lift value, the first lift reference value, and the second lift reference value.

[0270] According to the second embodiment, the first detector continuously detects the first payout amount or the first lifting height value, and the second detector continuously detects the second payout amount or the second lifting height value, thereby enabling real-time determination of whether the bucket device is in an over-open or over-closed state.

[0271] A bucket control device according to a third aspect of the second technology preferably further comprises the following features in addition to the bucket control device according to the second aspect. That is, in a bucket device according to the third aspect, the controller determines that the bucket device is in the over-open state when the relative difference is greater than the first reference value, and determines that the bucket device is in the over-closed state when the relative difference is less than the second reference value. Alternatively, the controller determines that the bucket device is in the over-open state when the difference in lifting value is greater than the first lifting reference value, and determines that the bucket device is in the over-closed state when the difference in lifting value is less than the second lifting reference value.

[0272] According to the third embodiment, it is possible to easily determine whether the bucket device is in an over-open or over-closed state from the relative difference, which is the difference between the first and second payout amounts. Alternatively, it is possible to easily determine whether the bucket device is in an over-open or over-closed state from the difference in lifting values, which is the difference between the first lifting value and the second lifting value.

[0273] A bucket control device according to a fourth aspect of the second technology is preferably a bucket control device according to a second or third aspect that further includes the following features. That is, in the fourth aspect, the construction machine further includes a first proportional valve capable of stopping the rotation of the first winch drum and a second proportional valve capable of stopping the rotation of the second winch drum, and the controller, when it is determined that the bucket device is in the over-open state, inputs a command to the proportional valve of the first proportional valve and the second proportional valve corresponding to the opening / closing drum to stop the rotation of the opening / closing drum in the unwinding direction, and the controller, when it is determined that the bucket device is in the over-closed state, inputs a command to the proportional valve of the first proportional valve and the second proportional valve corresponding to the opening / closing drum to stop the rotation of the opening / closing drum in the winding direction.

[0274] According to the fourth embodiment, if the bucket device is determined to be in an over-open state, a command is input to the proportional valve corresponding to the opening / closing drum responsible for opening and closing the bucket device to stop the rotation of the opening / closing drum in the unwinding direction, thereby stopping the rotation of the opening / closing drum and reducing the slack in the rope responsible for opening and closing the bucket device. Also, if the bucket device is determined to be in an over-closed state, a command is input to the proportional valve corresponding to the opening / closing drum responsible for opening and closing the bucket device to stop the rotation of the opening / closing drum in the winding direction, thereby stopping the rotation of the opening / closing drum and reducing the slack in the rope that supports the bucket device.

[0275] A bucket control device according to a fifth aspect of the second technology is preferably a bucket control device according to any of the second to fourth aspects, further comprising the following features. In other words, in the bucket control device according to the fifth embodiment, the first reference value is set to the average of a first reference value set when the lifting height of the bucket device is at a predetermined maximum lifting height and a first reference value set when the lifting height of the bucket device is at a predetermined minimum lifting height; the second reference value is set to the average of a second reference value set when the lifting height of the bucket device is at the maximum lifting height and a second reference value set when the lifting height of the bucket device is at the minimum lifting height; the first lifting height reference value is set to the average of a first lifting height reference value set when the lifting height of the bucket device is at the maximum lifting height and a first lifting height reference value set when the lifting height of the bucket device is at the minimum lifting height; and the second lifting height reference value is set to the average of a second lifting height reference value set when the lifting height of the bucket device is at the maximum lifting height and a second lifting height reference value set when the lifting height of the bucket device is at the minimum lifting height.

[0276] According to the fifth aspect, the first reference value, second reference value, first lifting height reference value, and second lifting height reference value are all set to the average value of the value set when the bucket device is at its maximum lifting height and the value set when the bucket device is at its minimum lifting height. This reduces the influence of changes in the effective radius of the first and second winch drums due to changes in the winding layers of the first and second winch drums. As a result, the accuracy of determining the over-open and over-closed states of the bucket device is improved.

[0277] A bucket control device according to the sixth aspect of the second technology preferably further comprises the following features in a bucket control device according to any of the second to fifth aspects. That is, in the bucket control device according to the sixth aspect, the controller calculates a first change amount which is the difference between the first payout amount of the first winch rope when the bucket device is in the predetermined open state and the first payout amount of the first winch rope when the bucket device is in the predetermined closed state, and a second change amount which is the difference between the second payout amount of the second winch rope when the bucket device is in the predetermined open state and the second payout amount of the second winch rope when the bucket device is in the predetermined closed state, and if the first change amount is greater than the second change amount, the controller determines that the first winch rope is the rope responsible for opening and closing the bucket device, and if the first change amount is less than the second change amount, the controller determines that the second winch rope is the rope responsible for opening and closing the bucket device. The controller determines that the first winch rope is responsible for opening and closing the bucket device, or calculates a first lift change amount which is the difference between the first lift value of the first winch rope when the bucket device is in the predetermined open state and the first lift value of the first winch rope when the bucket device is in the predetermined closed state, and a second lift change amount which is the difference between the second lift value of the second winch rope when the bucket device is in the predetermined open state and the second lift value of the second winch rope when the bucket device is in the predetermined closed state. If the first lift change amount is greater than the second lift change amount, the controller determines that the first winch rope is responsible for opening and closing the bucket device, and if the first lift change amount is less than the second lift change amount, the controller determines that the second winch rope is responsible for opening and closing the bucket device.

[0278] According to the sixth aspect, by determining the rope responsible for opening and closing the bucket device, it is possible to prevent the operator from mistakenly using the wrong rope.

[0279] A bucket control device according to the seventh aspect of the second technology is preferably a bucket control device according to any of the second to sixth aspects, further comprising the following features: In the seventh aspect, the construction machine further comprises an alarm device, and the controller activates the alarm device when it is determined that the bucket device is in the over-open state or the over-closed state.

[0280] According to the seventh aspect, if the bucket device is determined to be in an over-open or over-closed state, the alarm device will activate and generate an alarm sound, allowing the operator to quickly recognize that the bucket device is in an over-open or over-closed state.

[0281] A bucket control device according to the eighth aspect of the second technology comprises a first winch drum for paying out and winding up a first winch rope, a second winch drum for paying out and winding up a second winch rope, a bucket device connected to the first and second winch ropes and capable of opening and closing and moving up and down in accordance with the rotation of the first and second winch drums, a first winch operating device that is given an operation to rotate the first winch drum, a second winch operating device that is given an operation to rotate the second winch drum, and a controller that performs over-opening suppression control, wherein the over-opening suppression control is a control in which, when the bucket device is in an over-open state, being operated in the direction of further opening the bucket device from a predetermined open state, the controller stops paying out the rope of the opening / closing drum, which is the drum responsible for opening and closing the bucket device, among the first and second winch drums.

[0282] According to the eighth aspect, when the bucket device is in an over-open state, the extension of the drum responsible for opening and closing the bucket device is stopped, which reduces slack in the winch rope and suppresses problems such as rope entanglement.

[0283] A bucket control device according to the ninth aspect of the second technology comprises a first winch drum for paying out and winding up a first winch rope, a second winch drum for paying out and winding up a second winch rope, a bucket device connected to the first and second winch ropes and capable of opening and closing and moving up and down in accordance with the rotation of the first and second winch drums, a first winch operating device that is given an operation to rotate the first winch drum, a second winch operating device that is given an operation to rotate the second winch drum, and a controller that performs over-closing suppression control, wherein the over-closing suppression control is a control in which the controller stops winding up the rope of the opening and closing drum when the bucket device is in an over-closed state, being operated in the direction of closing the bucket device further from a predetermined closed state.

[0284] According to the ninth aspect, when the bucket device is in an over-closed state, the winding of the drum responsible for opening and closing the bucket device is stopped, which reduces slack in the winch rope and suppresses problems such as rope entanglement.

[0285] A construction machine equipped with a bucket control device according to the tenth embodiment of the second technology comprises the first winch drum, the second winch drum, the bucket device, the first winch operating device, the second winch operating device, and a bucket control device according to any of the first to seventh embodiments.

[0286] According to the tenth embodiment, when the bucket device is in an over-open state, the extension of the drum responsible for opening and closing the bucket device is stopped, and when the bucket device is in an over-closed state, the winding of the drum responsible for opening and closing the bucket device is stopped, thereby reducing rope slack and suppressing problems such as rope entanglement, making it possible to provide a construction machine equipped with a bucket control device.

[0287] An eleventh aspect of the second technology is a bucket control method for a construction machine, comprising: a first winch drum for paying out and reeling in a first winch rope; a second winch drum for paying out and reeling in a second winch rope; a bucket device connected to the first and second winch ropes and capable of opening and closing and moving up and down in accordance with the rotation of the first and second winch drums; a first winch operating device that is given an operation to rotate the first winch drum; and a second winch operating device that is given an operation to rotate the second winch drum, wherein the controller stops paying out the rope from the opening / closing drum, which is one of the first and second winch drums responsible for opening and closing the bucket device, when the bucket device is in an over-open state, being operated in the direction of further opening the bucket device from a predetermined open state; and the controller stops reeling in the rope from the opening / closing drum, when the bucket device is in an over-closed state, being operated in the direction of further closing the bucket device from a predetermined closed state.

[0288] According to the eleventh embodiment, when the bucket device is in an over-open state, the extension of the drum responsible for opening and closing the bucket device is stopped, and when the bucket device is in an over-closed state, the winding of the drum responsible for opening and closing the bucket device is stopped, thereby providing a bucket control method that reduces slack in the winch rope and suppresses problems such as rope entanglement.

Claims

1. A bucket control device for a construction machine comprising: a first winch drum for paying out and reeling in a first winch rope; a second winch drum for paying out and reeling in a second winch rope; and a bucket device connected to the first and second winch ropes, which is openable and closable and raised and lowered in accordance with the rotation of the first and second winch drums, wherein the bucket control device comprises a controller for determining the open / closed state of the bucket device and notifying the operator of the determined open / closed state of the bucket device.

2. The bucket control device according to claim 1, wherein the construction machine comprises a first detector for detecting a first payout amount, which is the amount of the first winch rope paid out, or a first lifting value of the first winch rope; and a second detector for detecting a second payout amount, which is the amount of the second winch rope paid out, or a second lifting value of the second winch rope, wherein the controller calculates the degree of opening or closing of the bucket device based on the difference between the first payout amount of the first winch rope and the second payout amount of the second winch rope, a first reference value which is the difference when the bucket device is in a fully open state, and a second reference value which is the difference when the bucket device is in a fully closed state, or The controller is a bucket control device that calculates the degree of opening and closing of the bucket device based on the difference in lifting values ​​between the first lifting value of the first winch rope and the second lifting value of the second winch rope, a first lifting reference value which is the difference in lifting values ​​when the bucket device is in the fully open state, and a second lifting reference value which is the difference in lifting values ​​when the bucket device is in the fully closed state.

3. A bucket control device according to claim 2, wherein the controller presets a first reference value and a second reference value, or a first lifting reference value and a second lifting reference value; the controller calculates the first reference value from the difference between the first payout amount of the first winch rope and the second payout amount of the second winch rope when the bucket device is in the fully open state; calculates the second reference value from the difference between the first payout amount of the first winch rope and the second payout amount of the second winch rope when the bucket device is in the fully closed state; calculates the first lifting reference value from the difference in lifting values ​​between the first lifting value of the first winch rope and the second lifting value of the second winch rope when the bucket device is in the fully open state; and calculates the second lifting reference value from the difference in lifting values ​​between the first lifting value of the first winch rope and the second lifting value of the second winch rope when the bucket device is in the fully closed state.

4. A bucket control device according to claim 3, wherein the first reference value is set to the average of a first reference value set when the lifting height of the bucket device is at a predetermined maximum lifting height and a first reference value set when the lifting height of the bucket device is at a predetermined minimum lifting height; the second reference value is set to the average of a second reference value set when the lifting height of the bucket device is at the maximum lifting height and a second reference value set when the lifting height of the bucket device is at the minimum lifting height; the first lifting height reference value is set to the average of a first lifting height reference value set when the lifting height of the bucket device is at the maximum lifting height and a first lifting height reference value set when the lifting height of the bucket device is at the minimum lifting height; and the second lifting height reference value is set to the average of a second lifting height reference value set when the lifting height of the bucket device is at the maximum lifting height and a second lifting height reference value set when the lifting height of the bucket device is at the minimum lifting height.

5. A bucket control device according to any one of claims 2 to 4, wherein the controller calculates a first change amount which is the difference between a first payout amount of the first winch rope when the bucket device is in the fully open state and a first payout amount of the first winch rope when the bucket device is in the fully closed state, and a second change amount which is the difference between a second payout amount of the second winch rope when the bucket device is in the fully open state and a second payout amount of the second winch rope when the bucket device is in the fully closed state, and determines that the first winch rope is responsible for opening and closing the bucket device if the first change amount is greater than the second change amount, and determines that the second winch rope is responsible for opening and closing the bucket device if the first change amount is less than the second change amount.

6. A bucket control device according to any one of claims 2 to 4, wherein the controller calculates a first lift change amount which is the difference between a first lift value of the first winch rope when the bucket device is in the fully open state and a first lift value of the first winch rope when the bucket device is in the fully closed state, and a second lift change amount which is the difference between a second lift value of the second winch rope when the bucket device is in the fully open state and a second lift value of the second winch rope when the bucket device is in the fully closed state, and determines that the first winch rope is the rope responsible for opening and closing the bucket device if the first lift change amount is greater than the second lift change amount, and determines that the second winch rope is the rope responsible for opening and closing the bucket device if the first lift change amount is less than the second lift change amount.

7. A bucket control device according to any one of claims 1 to 6, wherein the construction machine further comprises a first winch operating device that is given an operation to rotate the first winch drum, and a second winch operating device that is given an operation to rotate the second winch drum, wherein the controller is configured to perform at least one of over-opening suppression control and over-closing suppression control, the over-opening suppression control is a control by which the controller stops paying out the rope of the opening / closing drum, which is the drum responsible for opening and closing the bucket device, among the first winch drum and the second winch drum, when the bucket device is in an over-open state where it is being operated in the direction of further opening the bucket device from a predetermined open state, and the over-closing suppression control is a control by which the controller stops winding up the rope of the opening / closing drum when the bucket device is in an over-closed state where it is being operated in the direction of further closing the bucket device from a predetermined closed state.

8. The bucket control device according to claim 7, wherein the construction machine comprises: a first detector for detecting a first payout amount which is the amount of the first winch rope paid out, or a first lifting value which is the lifting value of the first winch rope; a second detector for detecting a second payout amount which is the amount of the second winch rope paid out, or a second lifting value which is the lifting value of the second winch rope; and a storage unit. The storage unit pre-stores a first reference value which is the difference between the amount of the first winch rope unwound and the amount of the second winch rope unwound when the bucket device is in the predetermined open state, and a second reference value which is the difference between the amount of the first winch rope unwound and the amount of the second winch rope unwound when the bucket device is in the predetermined closed state, or the storage unit pre-stores a first lifting reference value which is the difference between the lifting height of the first winch rope and the lifting height of the second winch rope when the bucket device is in the predetermined open state, and a second lifting reference value which is the difference between the lifting height of the first winch rope and the lifting height of the second winch rope when the bucket device is in the predetermined closed state. A bucket control device wherein the controller determines whether the bucket device is in either the over-open state or the over-closed state based on the relative difference which is the difference between the first discharge amount and the second discharge amount, the first reference value and the second reference value, or the controller determines whether the bucket device is in either the over-open state or the over-closed state based on the lift value difference which is the difference between the first lift value and the second lift value, the first lift reference value and the second lift reference value.

9. A bucket control device according to claim 8, wherein the controller determines that the bucket device is in the over-open state when the relative difference is greater than the first reference value, and determines that the bucket device is in the over-closed state when the relative difference is less than the second reference value, or the controller determines that the bucket device is in the over-open state when the difference in lifting height is greater than the first lifting height reference value, and determines that the bucket device is in the over-closed state when the difference in lifting height is less than the second lifting height reference value.

10. A bucket control device according to claim 8 or 9, wherein the construction machine further comprises a first proportional valve capable of stopping the rotation of the first winch drum, and a second proportional valve capable of stopping the rotation of the second winch drum, wherein the controller, when it is determined that the bucket device is in the over-open state, inputs a command to the proportional valve among the first and second proportional valves corresponding to the opening / closing drum to stop the rotation of the opening / closing drum in the unwinding direction, and the controller, when it is determined that the bucket device is in the over-closed state, inputs a command to the proportional valve among the first and second proportional valves corresponding to the opening / closing drum to stop the rotation of the opening / closing drum in the winding direction.

11. A bucket control device according to any one of claims 8 to 10, wherein the first reference value is set to the average of a first reference value set when the lifting height of the bucket device is at a predetermined maximum lifting height and a first reference value set when the lifting height of the bucket device is at a predetermined minimum lifting height; the second reference value is set to the average of a second reference value set when the lifting height of the bucket device is at the maximum lifting height and a second reference value set when the lifting height of the bucket device is at the minimum lifting height; the first lifting height reference value is set to the average of a first lifting height reference value set when the lifting height of the bucket device is at the maximum lifting height and a first lifting height reference value set when the lifting height of the bucket device is at the minimum lifting height; and the second lifting height reference value is set to the average of a second lifting height reference value set when the lifting height of the bucket device is at the maximum lifting height and a second lifting height reference value set when the lifting height of the bucket device is at the minimum lifting height.

12. In a bucket control device according to any one of claims 8 to 11, the controller calculates a first change amount which is the difference between the first payout amount of the first winch rope when the bucket device is in the predetermined open state and the first payout amount of the first winch rope when the bucket device is in the predetermined closed state, and a second change amount which is the difference between the second payout amount of the second winch rope when the bucket device is in the predetermined open state and the second payout amount of the second winch rope when the bucket device is in the predetermined closed state, and determines that the first winch rope is the rope responsible for opening and closing the bucket device if the first change amount is greater than the second change amount, and determines that the second winch rope is the rope responsible for opening and closing the bucket device if the first change amount is less than the second change amount, or the controller A bucket control device that calculates a first lift change amount, which is the difference between the first lift value of the first winch rope when the bucket device is in the predetermined open state and the first lift value of the first winch rope when the bucket device is in the predetermined closed state, and a second lift change amount, which is the difference between the second lift value of the second winch rope when the bucket device is in the predetermined open state and the second lift value of the second winch rope when the bucket device is in the predetermined closed state, and determines that the first winch rope is the rope responsible for opening and closing the bucket device if the first lift change amount is greater than the second lift change amount, and determines that the second winch rope is the rope responsible for opening and closing the bucket device if the first lift change amount is less than the second lift change amount.

13. A bucket control device according to any one of claims 8 to 12, wherein the construction machine further comprises an alarm device, and the controller activates the alarm device when the bucket device is determined to be in the over-open state or the over-closed state.

14. A bucket control device according to claim 1, wherein the construction machine further comprises a first winch operating device that is given an operation to rotate the first winch drum, and a second winch operating device that is given an operation to rotate the second winch drum, wherein the controller is configured to perform over-opening suppression control, and the over-opening suppression control is a control by which the controller stops paying out the rope of the opening / closing drum, which is the drum responsible for opening and closing the bucket device, among the first winch drum and the second winch drum, when the bucket device is in an over-open state where it is being operated in the direction of opening the bucket device further from a predetermined open state.

15. A bucket control device according to claim 1, wherein the construction machine further comprises a first winch operating device that is given an operation to rotate the first winch drum, and a second winch operating device that is given an operation to rotate the second winch drum, wherein the controller is configured to perform over-closing suppression control, and the over-closing suppression control is a control by which the controller stops winding up the rope of the opening / closing drum, which is the drum responsible for opening and closing the bucket device, from the first winch drum and the second winch drum, when the bucket device is in an over-closing state where it is being operated in the direction of closing the bucket device from a predetermined closed state.

16. A construction machine comprising: the first winch drum; the second winch drum; the bucket device; and the bucket control device according to any one of claims 1 to 15.

17. A bucket control method for a construction machine comprising: a first winch drum for paying out and reeling in a first winch rope; a second winch drum for paying out and reeling in a second winch rope; and a bucket device connected to the first and second winch ropes, which is openable and closable and raised and lowered in accordance with the rotation of the first and second winch drums, the bucket control method comprising: a controller determining the open / closed state of the bucket device and notifying the operator of the determined open / closed state of the bucket device.

18. A bucket control method according to claim 17, wherein the construction machine further comprises a first winch operating device that is given an operation to rotate the first winch drum, and a second winch operating device that is given an operation to rotate the second winch drum, the bucket control method comprising at least one of the following: when the bucket device is in an over-open state, being operated in the direction of further opening the bucket device from a predetermined open state, the controller stops paying out the rope from the opening / closing drum, which is one of the first and second winch drums responsible for opening and closing the bucket device; and when the bucket device is in an over-closed state, being operated in the direction of further closing the bucket device from a predetermined closed state, the controller stops winding up the rope from the opening / closing drum.

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