Bucket control device, construction machine, and method for maintaining the open / closed state of a bucket.

Abstract

This invention provides a technology that can prevent the bucket from changing from a closed state to an open state or from an open state to a closed state against the operator's will during the luffing motion of the luffing member. [Solution] The bucket control device 200 is a control device for a construction machine 100 comprising a machine body, a luffing member 104, a first winch drum DR1, a second winch drum DR2, and a bucket device 10. The bucket control device 200 includes a controller 70 that performs luffing synchronization control to maintain the open and closed state of the buckets 13, 13 by adjusting one or both of the payout amounts of the first winch rope R1 and the second winch rope R2 in accordance with the angle change of the luffing member 104 during the luffing operation of the luffing member 104.

Description

Technical Field

[0001] The present disclosure relates to a technology for a construction machine equipped with a bucket device.

Background Art

[0002] Conventionally, construction machines equipped with bucket devices are known (for example, Patent Documents 1-2).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] Even when the winch drum for opening and closing the bucket device is stopped, during the hoisting operation of the hoisting member including the boom, against the operator's intention, the bucket may change from the closed state to the open state, or the bucket may change from the open state to the closed state.

Means for Solving the Problems

[0005] An object of the present disclosure is to provide a technology capable of suppressing the bucket from changing from the closed state to the open state or from the open state to the closed state against the operator's intention during the hoisting operation of the hoisting member.

[0006] A bucket control device according to a first embodiment is a control device for a construction machine, comprising: a machine body; a luffing member that can be raised and lowered relative to the machine body; a first winch drum that pays out and retracts a first winch rope hanging from the luffing member; a second winch drum positioned differently from the first winch drum and that pays out and retracts a second winch rope hanging from the luffing member; and a bucket device to which the first winch rope and the second winch rope are connected, and which has a bucket that can be opened and closed in accordance with the operation of the first winch drum and the operation of the second winch drum. The bucket control device includes a controller that performs luffing synchronization control to maintain the open and closed state of the bucket by adjusting one or both of the payout amounts of the first winch rope and the second winch rope in accordance with the angle change of the luffing member during the luffing operation of the luffing member.

[0007] If the luffing synchronization control is not performed, even if the first and second winch drums for opening and closing the bucket are stopped, the bucket may change from a closed state to an open state or from an open state to a closed state during the luffing operation of the luffing member due to a difference in the relative position of the first winch drum with respect to the luffing member and the relative position of the second winch drum with respect to the luffing member. In other words, if the luffing synchronization control is not performed, the open or closed state of the bucket may change against the operator's will during the luffing operation of the luffing member.

[0008] On the other hand, in the bucket control device according to the first embodiment, the controller performs luffing synchronization control to maintain the open and closed state of the bucket by adjusting one or both of the payout amounts of the first winch rope and the second winch rope in accordance with the angle change of the luffing member during the luffing operation of the luffing member. This suppresses the bucket from changing from a closed state to an open state or from an open state to a closed state against the operator's will during the luffing operation of the luffing member.

[0009] A bucket control device according to a second embodiment preferably comprises the following additional configurations in addition to those of the bucket control device according to the first embodiment. That is, in the bucket control device according to the second embodiment, the controller preferably calculates, in the luffing synchronization control, the amount of change in a first distance from the first winch drum to a predetermined first part of the luffing member, which changes in accordance with the angle change, and the amount of change in a second distance from the second winch drum to a predetermined second part of the luffing member, which changes in accordance with the angle change, and adjusts one or both of the payout amount of the first winch rope and the payout amount of the second winch rope based on the first and second distance change amounts.

[0010] If the luffing synchronization control is not performed, the relative position of the first winch drum with respect to the luffing member and the relative position of the second winch drum with respect to the luffing member will be different, which may cause a difference between the first distance change and the second distance change during the luffing operation of the luffing member, and as a result, the opening and closing state of the bucket may change.

[0011] On the other hand, in the bucket control device according to the second embodiment, the controller adjusts either or both of the amount of the first winch rope unwinded and the amount of the second winch rope unwinded based on the first distance change and the second distance change, thereby maintaining the open or closed state of the bucket.

[0012] In the second embodiment, if the first winch rope extends from the first winch drum to the upper end of the luffing member and hangs down from the upper end to the bucket device, the predetermined first portion may be the upper end of the luffing member. Similarly, if the second winch rope extends from the second winch drum to the upper end of the luffing member and hangs down from the upper end to the bucket device, the predetermined second portion may be the upper end of the luffing member.

[0013] A bucket control device according to a third embodiment preferably comprises the following additional configurations in addition to those of a bucket control device according to a first or second embodiment. That is, in the third embodiment, the construction machine further comprises a luffing device which is an operating device that receives luffing operations for luffing the luffing member, and the controller preferably performs luffing synchronization control when the luffing device receives the luffing operation. In this third embodiment, the controller can perform the luffing synchronization control at an appropriate timing based on the luffing operation.

[0014] The construction machine according to the fourth embodiment comprises the machine body, the luffing member, the first winch drum, the second winch drum, the bucket device, and a bucket control device according to any one of the first to third embodiments. In this fourth embodiment, the controller can prevent the bucket from changing from a closed state to an open state or from an open state to a closed state against the operator's will during the luffing operation of the luffing member.

[0015] The fifth embodiment of the bucket opening / closing state maintenance method is a method using a bucket control device according to any one of the first to third embodiments. The bucket opening / closing state maintenance method includes the controller adjusting one or both of the payout amounts of the first winch rope and the second winch rope in accordance with the angle change of the luffing member during the luffing operation of the luffing member to maintain the opening / closing state of the bucket. This fifth embodiment of the bucket opening / closing state maintenance method can prevent the bucket from changing from a closed state to an open state or from an open state to a closed state against the operator's will during the luffing operation of the luffing member. [Effects of the Invention]

[0016] As described above, this disclosure provides a technology that can prevent the bucket from changing from a closed state to an open state or from an open state to a closed state against the operator's will during the luffing motion of the luffing member. [Brief explanation of the drawing]

[0017] [Figure 1] This is a side view showing a crane equipped with a bucket control device according to the first embodiment of this disclosure. [Figure 2] This block diagram shows the first winch, second winch, and bucket device of the crane, and the main components related thereto. [Figure 3] This diagram shows the parts of the hydraulic circuit of the crane that are related to the first winch and the second winch. [Figure 4] This is a diagram illustrating the opening and closing operation of the bucket device provided by the crane. [Figure 5] This diagram illustrates how the bucket changes from a closed state to an open state due to the luffing motion of the luffing member. [Figure 6] This diagram illustrates how the bucket changes from an open state to a closed state due to the luffing motion of the luffing member. [Figure 7] This figure illustrates the relationship between a first distance from the first winch drum to a predetermined first part of the luffing member and the luffing angle of the luffing member, and the relationship between a second distance from the second winch drum to a predetermined second part of the luffing member and the luffing angle of the luffing member. [Figure 8] This flowchart shows an example of the calculation process performed by the controller of the aforementioned bucket control device. [Figure 9] This block diagram shows the controller and related main components of a bucket control device according to a second embodiment of the present disclosure. [Figure 10] This flowchart shows an example of the calculation process performed by the controller according to the second embodiment. [Figure 11] This flowchart shows an example of the calculation process performed by the controller according to the second embodiment. [Figure 12] This figure shows an example of a map illustrating the relationship between the target pilot pressure and the commanded current value. [Modes for carrying out the invention]

[0018] Embodiments of this disclosure will be described with reference to the drawings.

[0019] [First Embodiment] Figure 1 shows a crane 100, which is a construction machine according to this 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 plurality of winches arranged on the upper slewing body 102, and a bucket device 10.

[0020] The lower body 101 is a self-propelled lower traveling body equipped with a traveling device such as a crawler traveling device. However, the lower body in this disclosure may be a structure such as a support base that rotatably supports the upper rotating body 102 and is not self-propelled.

[0021] The upper slewing body 102 comprises a slewing frame 103 rotatably mounted on the lower body 101, a cabin 114 supported at the front of the slewing frame 103, and a counterweight 115 supported at the rear of the slewing frame 103. The lower body 101 and the upper slewing body 102 are examples of the machine body in this disclosure. However, if the lower body is the structure such as the support base, the machine body in this disclosure may consist of the structure and the upper slewing body.

[0022] The luffing member 104 includes a boom that is luffably supported on the slewing frame 103. However, the luffing member in this disclosure may also include a boom and a jib (not shown) that is rotatably supported on the upper end of the boom. The luffing member 104 includes a luffing member body 104A and a plurality of sheaves. The luffing member body 104A is the portion of the upper slewing body 102 that is positioned to protrude from the slewing frame 103 and constitutes the majority of the luffing member 104. In the specific example shown in Figure 1, the luffing member body 104A is composed of a boom having a lattice structure. The plurality of sheaves include a first point sheave 105, a second point sheave 106, a first idler sheave 112, and a second idler sheave 113, which are attached to the upper end of the luffing member body 104A as shown in Figure 1.

[0023] 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 upper end 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 R3 is wrapped around the lower spreader 110 and the upper spreader 109.

[0024] The aforementioned plurality of winches include a first winch WC1, a second winch WC2, and a luffing winch WC3. The first winch WC1 has a first winch drum DR1 for paying out and winding in the first winch rope R1 (wire rope). The second winch WC2 has a second winch drum DR2 for paying out and winding in the second winch rope R2 (wire rope). The luffing winch WC3 has a luffing winch drum DR3 for paying out and winding in the luffing rope R3 (wire rope).

[0025] The first winch WC1 and the second winch WC2 open and close the bucket device 10 and raise and lower it.

[0026] The luffing rope R3 extends from the luffing winch drum DR3 to the lower spreader 110 and is wrapped around the lower spreader 110 and the upper spreader 109. 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 R3. As this distance decreases or increases, the luffing member 104 rumbles. In other words, the luffing winch WC3 can make the luffing member 104 rumble relative to the upper slewing body 102 by winding in or unwinding the luffing rope R3.

[0027] Figure 2 is a block diagram showing the first winch WC1, the second winch WC2, and the bucket device 10 of the crane 100, as well as the main components related thereto. Figure 3 is a diagram showing the portion of the hydraulic circuit of the crane 100 related to the first winch WC1 and the second winch WC2.

[0028] 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 40, 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 40, and a reduction gear 47.

[0029] The first winch rope R1 is an opening / 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 for paying out and reeling in the first winch rope R1 as an opening / closing rope, and the second winch drum DR2 is a support drum for paying out and reeling in the second winch rope R2 as a support rope.

[0030] The first winch drum DR1 is supported by a support member (not shown) on the upper slewing body 102 so as to be rotatable around a horizontal axis, enabling the first winch rope R1 to be paid out and retracted. The second winch drum DR2 is supported by a support member (not shown) on the upper slewing body 102 so as to be rotatable around a horizontal axis, enabling the second winch rope R2 to be paid out and retracted.

[0031] The first winch drum DR1 and the second winch drum DR2 are positioned at different locations from each other. In this embodiment, the first winch drum DR1 and the second winch drum DR2 are located behind the luffing member 104, and the second winch drum DR2 is located behind the first winch drum DR1. However, the first winch drum DR1 may be located behind the second winch drum DR2.

[0032] The longitudinal direction is based on the orientation of the upper rotating body 102. Specifically, the horizontal direction from the counterweight 115 toward the cabin 114 is forward, and the opposite direction is backward. The lateral direction is the horizontal direction perpendicular to the longitudinal direction.

[0033] The first point sheave 105 and the second point sheave 106 are arranged side by side and attached to the upper end of the undulating member 104. The first idler sheave 112 and the second idler sheave 113 are arranged side by side and attached to the upper end of the undulating member 104. The first idler sheave 112 is located behind the first point sheave 105, and the second idler sheave 113 is located behind the second point sheave 106.

[0034] The first winch rope R1 extends from the first winch drum DR1 to the upper end of the luffing member 104, hangs down from the upper end, and is connected to the bucket device 10. Specifically, the first winch rope R1 is supported by the first idler sheave 112 and the first point sheave 105, and hangs down from the first point sheave 105. The second winch rope R2 extends from the second winch drum DR2 to the upper end of the luffing member 104, hangs down from the upper end, and is connected to the bucket device 10. Specifically, the second winch rope R2 is supported by the second idler sheave 113 and the second point sheave 106, and hangs down from the second point sheave 106. The lower ends (tips) of the first winch rope R1 and the second winch rope R2 are each connected to the bucket device 10.

[0035] The bucket device 10 is a working device known as a clamshell bucket. The bucket device 10 has buckets 13, 13 to which the first winch rope R1 and the second winch rope R2 are connected, and which can be opened and closed and raised and lowered in accordance with the operation of the first winch drum DR1 and the second winch drum DR2.

[0036] Specifically, as shown in Figure 4, 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. The right side of Figure 4 shows the open state in which the buckets 13, 13 of the bucket device 10 are open, and the left side of Figure 4 shows the closed state in which the buckets 13, 13 of the bucket device 10 are closed.

[0037] 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.

[0038] 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, 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.

[0039] 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.

[0040] The first winch rope R1 (the opening / closing rope) 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 (the support rope) is fixed to the upper member 11.

[0041] The first winch motor 34 and the second winch motor 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).

[0042] 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.

[0043] The first clutch brake 40 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 unfurled from the first winch drum DR1 by the weight of the bucket device 10. The first clutch brake 40 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.

[0044] Similarly, the second clutch brake 40 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 40 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.

[0045] The aforementioned connection state allows for the unwinding and winding of the first winch rope R1 and the second winch rope R2 by the driving force of the first winch motor 34 and the second winch motor 35. That is, when the first winch motor 34 and the second winch motor 35 are driven in the aforementioned connection state, the driving force of the first winch motor 34 and the second winch motor 35 is transmitted to the first winch drum DR1 and the second winch drum DR2, respectively, via the reduction gears 47, 47. When the first winch drum DR1 and the second winch drum DR2 rotate, the first winch rope R1 and the second winch rope R2 are unwinded or wound in.

[0046] The free state is a state in which the first winch rope R1 and the second winch rope R2 can be unfurled from the first winch drum DR1 and the second winch drum DR2 by the tension of the first winch rope R1 and the second winch rope 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 winch rope R1 and the second winch rope R2 can be unfurled from the first winch drum DR1 and the second winch drum DR2 without rotating the first winch motor 34 and the second winch motor 35 in the unfurling direction of the first winch rope R1 and the second winch rope R2.

[0047] Furthermore, the first clutch brake 40 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 40 can apply a second braking force to the second winch drum DR2, that is, it can brake the second winch drum DR2.

[0048] 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 40 and the second braking force of the second clutch brake 40 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.

[0049] In this embodiment, the first clutch brake 40 and the second clutch brake 40 are so-called wet brakes and each comprises 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 lubricating oil.

[0050] 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, each of the first clutch brake 40 and the second clutch brake 40 enters the free state, thereby allowing the bucket device 10 to descend (free fall) by its own weight. Conversely, when the multiple brake discs 41 enter the contact state, each of the first clutch brake 40 and the second clutch brake 40 enters the connected state.

[0051] More specifically, each of the first clutch brake 40 and the second clutch brake 40 is equipped with a spring 46, and each of the first clutch brake 40 and the second clutch brake 40 has a pair of oil chambers 43, 44 formed therein, and the piston 42 has a flange 45 that separates the pair of oil chambers 43, 44. When the hydraulic pressure applied to the pair of oil chambers 43, 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 the hydraulic pressure applied to the other oil chamber 43 by a predetermined amount or more, the multiple brake discs 41 come apart from each other.

[0052] The crane 100 includes a first control valve 32, a second control valve 33, a first payout proportional valve 61A, a first retraction proportional valve 61B, a second payout proportional valve 63A, a second retraction proportional valve 63B, a first brake proportional valve 62, a second brake proportional valve 64, and a plurality of operating devices. In this embodiment, each of the proportional valves 61A, 61B, 62, 63A, 63B, and 64 is an electromagnetic proportional pressure reducing valve.

[0053] 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 control valve 32 and the second control valve 33 is composed of a hydraulic pilot switching valve having a pair of pilot ports.

[0054] The pair of pilot ports are an unwinding pilot port and a winding pilot port. When no pilot pressure is applied to either pilot port, the first control valve 32 and the second control valve 33 are held in a neutral position, shutting off the winch motor corresponding to the control valve (hereinafter referred to as the "corresponding winch motor") from the hydraulic pump 31. When pilot pressure is applied to the unwinding pilot port, the first control valve 32 and the second control valve 33 open to form an oil passage for rotating the corresponding winch motor in the unwinding direction, that is, an oil passage for supplying hydraulic fluid from the hydraulic pump 31 to the corresponding winch motor in the unwinding direction. When pilot pressure is applied to the winding pilot port, the first control valve 32 and the second control valve 33 open to form an oil passage for rotating the corresponding winch motor in the winding direction, 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 degrees of the first control valve 32 and the second control valve 33 increase with increasing pilot pressure to allow the hydraulic fluid to flow at a flow rate corresponding to the pilot pressure input to the control valve.

[0055] 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 a controller 70 (described later), 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.

[0056] Similarly, the second dispensing proportional valve 63A is interposed between a pilot hydraulic source (not shown) and the dispensing pilot port of the second control valve 33, and opens to allow a pilot pressure proportional to the second dispensing command to be input to the dispensing pilot port when a second dispensing command, which is an electrical signal, is input to the proportional valve 63A from the controller 70. The second retracting proportional valve 63B is interposed between the pilot hydraulic source and the retracting pilot port of the second control valve 33, and opens to allow a pilot pressure proportional to the second retracting command to be input to the retracting pilot port when a second retracting command, which is an electrical signal, is input to the proportional valve 63B from the controller 70.

[0057] The first proportional brake valve 62 is interposed between the pilot hydraulic power source P and the first clutch brake 40. When a first brake command, which is an electrical signal, is input to the proportional valve 62 from the controller 70, 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 40. As a result, the first proportional brake valve 62 can switch the state of the first clutch brake 40 between the free state and the connected state.

[0058] Similarly, the second proportional brake valve 64 is interposed between the pilot hydraulic power source P and the second clutch brake 40. When a second brake command, which is an electrical signal, is input to the proportional valve 64 from the controller 70, the valve 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 40. This allows the second proportional brake valve 64 to switch the state of the second clutch brake 40 between the free state and the connected state.

[0059] As shown in Figures 1 to 3, the multiple operating devices include a first winch operating device 51, a second winch operating device 53, a first brake operating device 52, a second brake operating device 54, and a luffing operating device 55 (see Figure 1).

[0060] As shown in Figure 2, the first winch operating device 51 includes a first winch operating lever 51A and a first lever input detector 51B. The second winch operating device 53 includes a second winch operating lever 53A and a second lever input detector 53B. The first brake operating device 52 includes a first brake operating pedal 52A and a first pedal input detector 52B. The second brake operating device 54 includes a second brake operating pedal 54A and a second pedal input detector 54B. As shown in Figure 1, the luffing operating device 55 includes a luffing operating lever 55A and a luffing lever input detector 55B.

[0061] The first winch operating lever 51A is an operating member to which an operator performs a first lever operation to specify the rotation direction and rotation speed of the first winch drum DR1. Specifically, the first winch operating lever 51A is provided with either a first payout operation to rotate the first winch drum DR1 in the payout direction to pay out 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 lever operation.

[0062] The first lever input detector 51B detects the amount of the first lever operation (extend operation or retract operation) applied to the first winch operating lever 51A, and inputs the detection result to the controller 70.

[0063] Similarly, the second winch operating lever 53A is an operating member to which a second lever operation is performed by an operator to specify the rotation direction and rotation 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 lever operation.

[0064] The second lever input detector 53B detects the amount of operation of the second lever (extend or retract) applied to the second winch operating lever 53A, and inputs the detection result to the controller 70.

[0065] The first brake operation pedal 52A is an operating member to which a first pedal operation is performed by an operator to specify a first braking force on the first winch drum DR1. The first pedal input detector 52B detects the amount of the first pedal operation applied to the first brake operation pedal 52A and inputs the detection result to the controller 70.

[0066] The second brake operation pedal 54A is an operating member to which a second pedal operation is performed by the operator to specify a second braking force on the second winch drum DR2. The second pedal input detector 54B detects the amount of the second pedal operation applied to the second brake operation pedal 54A and inputs the detection result to the controller 70.

[0067] The luffing lever 55A is an operating member that allows an operator to perform luffing operations to specify the rotation direction and rotation speed of the luffing winch drum DR3. Specifically, the luffing lever 55A is provided with either a lowering operation to rotate the luffing winch drum DR3 in the unwinding direction to unwind the luffing rope R3, or an uprighting operation to rotate the luffing winch drum DR3 in the winding direction to wind up the luffing rope R3.

[0068] The luffing lever input detector 55B detects the amount of luffing operation (lowering operation or raising operation) applied to the luffing operation lever 55A and inputs the detection result to the controller 70.

[0069] When the luffing lever 55A is lowered, hydraulic fluid discharged from the hydraulic pump 31 is supplied to the luffing motor, which is a hydraulic motor not shown in the figure. As a result, the luffing member 104 performs a lowering operation in which the luffing angle θ, described later, gradually decreases. When the luffing lever 55A is raised, hydraulic fluid discharged from the hydraulic pump 31 is supplied to the luffing motor. As a result, the luffing member 104 performs a raised operation in which the luffing angle θ gradually increases. The luffing operation includes the lowering operation and the raised operation.

[0070] The crane 100 includes a luffing member angle detector 22, a first drum rotation detector 81, and a second drum rotation detector 82.

[0071] The luffing member angle detector 22 detects the luffing angle θ of the luffing member 104 and inputs the detection result to the controller 70. In this embodiment, the luffing member angle detector 22 detects the boom angle, which is the angle of the boom of the luffing member 104, as the luffing angle θ. The luffing angle θ is the angle of the luffing member 104 with respect to a predetermined reference. The reference may be, for example, a horizontal line or a horizontal plane, another straight line or another plane, the upper slewing body 102, or the lower body 101.

[0072] The first drum rotation detector 81 detects a first rotation amount ωm, which is the amount of rotation of the first winch drum DR1, and inputs the detection result to the controller 70. The second drum rotation detector 82 detects a second rotation amount ωa, which is the amount of rotation of the second winch drum DR2, and inputs the detection result to the controller 70.

[0073] Next, the bucket control device 200 according to this embodiment will be described.

[0074] The bucket control device 200 is a control device for the crane 100. In this embodiment, the bucket control device 200 is provided on the crane 100.

[0075] The bucket control device 200 includes a controller 70. The controller 70 performs luffing synchronization control to maintain the open and closed states of the buckets 13, 13 by adjusting one or both of the payout amounts of the first winch rope R1 and the second winch rope R2 in accordance with the angle change of the luffing member 104 during the luffing operation of the luffing member 104.Therefore, it is suppressed that the buckets 13, 13 will change from a closed state to an open state or from an open state to a closed state against the operator's will during the luffing operation of the luffing member 104.

[0076] The controller 70 comprises a computer having an arithmetic processing unit and memory. The undulation synchronization control by the controller 70 is achieved by the arithmetic processing unit executing a control program stored in the memory.

[0077] The controller 70 can calculate the amount of the first winch rope R1 to be unwound based on a first rotation amount ωm input from the first drum rotation detector 81. The controller 70 can also calculate the amount of the second winch rope R2 to be unwound based on a second rotation amount ωa input from the second drum rotation detector 82.

[0078] Figure 5 illustrates how, when the luffing synchronization control is not performed, the buckets 13, 13 change from a closed state to an open state during the luffing operation of the luffing member 104. Figure 6 illustrates how, when the luffing synchronization control is not performed, the buckets 13, 13 change from an open state to a closed state due to the luffing operation of the luffing member 104.

[0079] If the luffing synchronization control described above is not performed, even if the first winch drum DR1 and the second winch drum DR2 for opening and closing the buckets 13, 13 are stopped, a difference will occur between the change in the length of the first winch rope R1 from the first winch drum DR1 to the bucket device 10 during luffing operation and the change in the length of the second winch rope R2 from the second winch drum DR2 to the bucket device 10 during luffing operation, due to the difference in the relative position of the first winch drum DR1 with respect to the luffing member 104 and the relative position of the second winch drum DR2 with respect to the luffing member 104. For this reason, as shown in Figure 5, the bucket may change from a closed state (left diagram in Figure 5) to an open state (right diagram in Figure 5) during luffing operation, or the bucket may change from an open state (left diagram in Figure 6) to a closed state (right diagram in Figure 6).

[0080] If the luffing synchronization control described above is not performed, as shown in the right diagram of Figure 5, the portion of the second winch rope R2 hanging down from the upper end of the luffing member 104 remains taut during the luffing motion, while the portion of the first winch rope R1 hanging down from the upper end of the luffing member 104 becomes loose during the luffing motion. As a result, the buckets 13, 13 change from a closed state to an open state.

[0081] If the luffing synchronization control described above is not performed, as shown in the right diagram of Figure 6, the portion of the first winch rope R1 hanging down from the upper end of the luffing member 104 remains taut during the luffing operation, while the portion of the second winch rope R2 hanging down from the upper end of the luffing member 104 becomes loose during the luffing operation. As a result, the buckets 13, 13 of the bucket device 10 will change from an open state to a closed state.

[0082] In the bucket control device 200 according to this embodiment, the controller 70 performs the luffing synchronization control, so that the buckets 13, 13 do not change from a closed state to an open state or from an open state to a closed state against the operator's will during the luffing operation of the luffing member 104.

[0083] Figure 7 shows the first distance L, which is the distance from the first winch drum DR1 to a predetermined first part P1 of the luffing member 104. top-m The relationship between (θ) and the luffing angle θ of the luffing member 104, and the second distance L, which is the distance from the second winch drum DR2 to a predetermined second part P2 of the luffing member 104. top-a This diagram illustrates the relationship between (θ) and the elevation angle θ of the elevation member 104.

[0084] In this embodiment, the first part P1 is the upper end of the luffing member 104, and the second part P2 is the upper end of the luffing member 104. The first part P1 may be the part of the luffing member 104 that supports the first winch rope R1. Specifically, the first part P1 may be a first idler sheave 112 or a first point sheave 105 for supporting the first winch rope R1. The second part P2 may be the part of the luffing member 104 that supports the second winch rope R2. Specifically, the second part P2 may be a second idler sheave 113 or a second point sheave 106 for supporting the second winch rope R2.

[0085] In the undulation synchronization control, the controller 70 calculates a first distance change amount ΔL top-m and a second distance change amount ΔL top-a and adjusts one or both of the payout amounts of the first winch rope R1 and the second winch rope R2 based on the first distance change amount ΔL top-m and the second distance change amount ΔL top-a . The first distance change amount ΔL top-m is the change amount of the first distance L top-m (θ) that changes according to the angle change of the undulation member 104. The second distance change amount ΔL top-a is the change amount of the second distance L top-a (θ) that changes according to the angle change of the undulation member 104.

[0086] The controller 70 may pre-store the specifications data including the length of the undulation member 104, the data regarding the relative position of the first winch drum DR1 with respect to a specific part of the undulation member 104 (for example, the base end part of the undulation member 104), and the data regarding the relative position of the second winch drum DR2 with respect to the specific part of the undulation member 104. In this case, the controller 70 can calculate the first distance L top-m (θ) and the second distance L top-a (θ) that change according to the undulation angle θ from the geometric positional relationship among the undulation member 104, the first winch drum DR1, and the second winch drum DR2. Further, the controller 70 may pre-store the relational expressions representing the relationship between the undulation angle θ and the first distance L top-m (θ), and the relational expressions representing the relationship between the undulation angle θ and the second distance L top-a (θ). In this case, the controller 70 may calculate the first distance L top-m (θ) and the second distance L top-a (θ) using the undulation angle θ detected by the undulation member angle detector 22 and the above two relational expressions.

[0087] If the aforementioned luffing synchronization control is not performed, the relative position of the first winch drum DR1 with respect to the luffing member 104 and the relative position of the second winch drum DR2 with respect to the luffing member 104 will be different, resulting in a first distance change amount ΔL during the luffing operation of the luffing member 104. top-m and the second distance change ΔL top-a A difference arises between these two factors, which can result in changes to the open / closed state of the bucket. Specifically, this occurs as follows:

[0088] For the sake of explanation, the length of the portion of the first winch rope R1 from the upper end of the luffing member 104 to the bucket device 10 will be referred to as the first hanging portion length, and the length of the portion of the second winch rope R2 from the upper end of the luffing member 104 to the bucket device 10 will be referred to as the second hanging portion length.

[0089] The elevation angle θ decreases, and the second distance change ΔL top-a The first distance change ΔL top-m When the angle of elevation θ becomes greater than θ1, the decrease in the length of the second hanging portion of the second winch rope R2 becomes greater than the decrease in the length of the first hanging portion of the first winch rope R1. In this case, even if the buckets 13, 13 were closed when the elevation angle θ was θ1, as shown in the left diagram of Figure 5, when the elevation angle θ becomes θ2, the decrease in the length of the second hanging portion becomes greater than the decrease in the length of the first hanging portion. As a result, as shown in the right diagram of Figure 5, the second winch rope R2 becomes taut while the first winch rope R1 becomes slack, and the buckets 13, 13 may change to an open state.

[0090] On the other hand, in the bucket control device 200 according to this embodiment, the controller 70 controls the first distance change amount ΔL top-m and the second distance change ΔL top-aBased on this, the amount of the first winch rope R1 and the amount of the second winch rope R2 are adjusted, either or both, so that the open and closed states of the buckets 13, 13 can be maintained. This prevents the buckets 13, 13 from changing from a closed state to an open state or from an open state to a closed state against the operator's will during the luffing operation of the luffing member 104. In addition, slack in the first winch rope R1 or the second winch rope R2 during the luffing operation of the luffing member 104 is prevented.

[0091] In the elevation synchronization control, the controller 70 determines that the payout amount deviation, which is the difference between the amount of payout of the first winch rope R1 and the amount of payout of the second winch rope R2, is the first distance change amount ΔL. top-m and the second distance change ΔL top-a The amount of the first winch rope R1 and the amount of the second winch rope R2, or both, may be adjusted to match the distance change deviation er, which is the deviation from the distance change deviation. As the distance change deviation er increases, the degree of change in the open / closed state of the buckets 13, 13 also increases, but by adjusting the amount of the first winch rope R1 and the amount of the second winch rope R2, or both, to match the amount of the extension deviation to the distance change deviation er, the maintenance of the open / closed state of the buckets 13, 13 becomes more reliable.

[0092] As shown in Figure 7, the first distance L when the elevation angle θ of the elevation member 104 changes from θ1 to θ2 top-m The first distance change ΔL is the amount of change in ΔL. top-m This is expressed by the following equation (1): The second distance L when the elevation angle θ of the elevation member 104 changes from θ1 to θ2. top-a The second distance change ΔL is the amount of change in . top-a This is expressed by equation (2) below.

[0093]

number

[0094]

number

[0095] First distance change ΔL top-m and the second distance change ΔL top-a Each of these changes in accordance with the angle change of the undulating member 104.

[0096] The controller 70 controls the correction amount necessary for synchronized luffing control to maintain the open / closed state of the bucket 13 during the luffing operation of the luffing member 104, which is the first distance change amount ΔL. top-m and the second distance change ΔL top-a The calculation may be performed based on the first distance change amount ΔL. The controller 70 calculates the first distance change amount ΔL. top-m and the second distance change ΔL top-a By performing sequential calculations, it is possible to perform elevation synchronization control that takes the correction amount into consideration. Specifically, it is as follows:

[0097] [When θ1 > θ2] In the specific example shown in Figure 7, as described above, the first winch drum DR1 and the second winch drum DR2 are located behind the luffing member 104, and the second winch drum DR2 is located behind the first winch drum DR1. Therefore, as shown in Figure 7, when angle θ1 is greater than angle θ2 (θ1 > θ2), when the luffing member 104 performs the aforementioned tilting operation and the luffing angle θ decreases from θ1 to θ2, the first distance L top-m and second distance L top-a Each of them increases, and the second distance change ΔL top-a (i.e., the second distance L) top-a The increase in ΔL is the first distance change. top-m (i.e., the first distance L) top-m The increase in ΔL becomes greater than the first distance change. In this case, the controller 70 controls the first distance change ΔL. top-m and the second distance change ΔL top-a The distance change deviation er, which is the deviation from the given value, can be calculated, for example, using the following equation (3). The distance change deviation er is an example of the correction amount.

[0098] er=ΔL top-m -ΔL top-a (3)

[0099] When the luffing angle θ decreases from θ1 to θ2, the controller 70 adjusts either or both of the payout amounts of the first winch rope R1 and the second winch rope R2 so that the change in the payout amount of the second winch rope R2 is greater than the change in the payout amount of the first winch rope R1 by the absolute value |er| of the distance change deviation er. This ensures that the buckets 13, 13 remain closed during the luffing operation of the luffing member 104, even when the luffing angle θ decreases from θ1 to θ2. Specifically, when the luffing angle θ decreases from θ1 to θ2, the controller 70 may perform the following first open / closed state maintenance control, second open / closed state maintenance control, or third open / closed state maintenance control.

[0100] In the first open / closed state maintenance control, when the elevation angle θ decreases from θ1 to θ2, the controller 70 reduces the amount of the first winch rope R1 paid out, while keeping the amount of the second winch rope R2 paid out unchanged. That is, when the elevation angle θ decreases from θ1 to θ2, the controller 70 controls the operation of the first winch drum DR1 so that the first winch rope R1 is wound up by an absolute value |er|, and does not operate the second winch drum DR2.

[0101] In the second open / closed state maintenance control, when the elevation angle θ decreases from θ1 to θ2, the controller 70 increases the payout amount of the second winch rope R2 while keeping the payout amount of the first winch rope R1 unchanged. That is, when the elevation angle θ decreases from θ1 to θ2, the controller 70 controls the operation of the second winch drum DR2 so that the second winch rope R2 is paid out by an absolute value |er|, and does not operate the first winch drum DR1.

[0102] In the third open / closed state maintenance control, the controller 70 adjusts both the payout amount of the first winch rope R1 and the payout amount of the second winch rope R2 so that when the elevation angle θ decreases from θ1 to θ2, the change in the payout amount of the second winch rope R2 is greater than the change in the payout amount of the first winch rope R1 by an absolute value of |er|.

[0103] Furthermore, when the first winch rope R1 is unwound from the first winch drum DR1, the change in the amount of the first winch rope R1 unwound is a positive value, and when the first winch rope R1 is wound onto the first winch drum DR1, the change in the amount of the first winch rope R1 unwound is a negative value. Similarly, when the second winch rope R2 is unwound from the second winch drum DR2, the change in the amount of the second winch rope R2 unwound is a positive value, and when the second winch rope R2 is wound onto the second winch drum DR2, the change in the amount of the second winch rope R2 unwound is a negative value.

[0104] [When θ1 < θ2] Although not shown in the diagram, when angle θ1 is smaller than angle θ2 (θ1 < θ2), as the luffing member 104 performs the uprighting movement, the luffing angle θ increases from θ1 to θ2, and the first distance L top-m and second distance L top-a Each of them decreases, and the second distance change ΔL top-a (i.e., the second distance L) top-a The decrease in ΔL is the first distance change. top-m (i.e., the first distance L) top-m The amount of decrease is greater than the first distance change ΔL. In this case, the controller 70 controls the first distance change ΔL. top-m and the second distance change ΔL top-a The distance change deviation er, which is the deviation from the given point, can be calculated using the following equation (3), similar to the above.

[0105] er=ΔL top-m -ΔL top-a (3)

[0106] When the luffing angle θ increases from θ1 to θ2, the controller 70 adjusts either or both of the payout amounts of the first winch rope R1 and the second winch rope R2 so that the change in the payout amount of the second winch rope R2 is less than the change in the payout amount of the first winch rope R1 by the absolute value |er| of the distance change deviation er. This ensures that the buckets 13, 13 remain open during the luffing operation of the luffing member 104, even when the luffing angle θ increases from θ1 to θ2. Specifically, when the luffing angle θ increases from θ1 to θ2, the controller 70 may perform the following fourth, fifth, or sixth open / closed state maintenance control.

[0107] In the fourth open / closed state maintenance control, when the elevation angle θ increases from θ1 to θ2, the controller 70 increases the payout amount of the first winch rope R1, while keeping the payout amount of the second winch rope R2 unchanged. That is, when the elevation angle θ increases from θ1 to θ2, the controller 70 controls the operation of the first winch drum DR1 so that the first winch rope R1 is paid out by an absolute value |er|, and does not operate the second winch drum DR2.

[0108] In the fifth open / closed state maintenance control, when the elevation angle θ increases from θ1 to θ2, the controller 70 reduces the amount of the second winch rope R2 paid out, while keeping the amount of the first winch rope R1 unchanged. That is, when the elevation angle θ increases from θ1 to θ2, the controller 70 controls the operation of the second winch drum DR2 so that the second winch rope R2 is wound up by an absolute value |er|, and does not operate the first winch drum DR1.

[0109] In the sixth open / closed state maintenance control, the controller 70 adjusts both the payout amount of the first winch rope R1 and the payout amount of the second winch rope R2 so that when the elevation angle θ increases from θ1 to θ2, the change in the payout amount of the second winch rope R2 is less than the change in the payout amount of the first winch rope R1 by an absolute value of |er|.

[0110] The controller 70 may perform the luffing synchronization control when the luffing operation lever 55A of the luffing operation device 55 receives the luffing operation. In this case, the controller 70 can perform the luffing synchronization control at an appropriate timing based on the luffing operation.

[0111] Specifically, the controller 70 may perform the luffing synchronization control when a detection result indicating that the luffing operation lever 55A has received the luffing operation is input to the controller 70 from the luffing lever input detector 55B.

[0112] More specifically, if the controller 70 receives a detection result from the luffing lever input detector 55B indicating that the luffing lever 55A has been lowered, it may perform the first open / closed state maintenance control, the second open / closed state maintenance control, or the third open / closed state maintenance control in the luffing synchronization control. Alternatively, if the controller 70 receives a detection result from the luffing lever input detector 55B indicating that the luffing lever 55A has been raised, it may perform the fourth open / closed state maintenance control, the fifth open / closed state maintenance control, or the sixth open / closed state maintenance control in the luffing synchronization control.

[0113] Figure 8 is a flowchart showing an example of the calculation process for the elevation synchronization control performed by the controller 70.

[0114] In step S11, the controller 70 determines whether or not predetermined power synchronization mode conditions are met. The power synchronization mode conditions are conditions for determining whether or not to set the control mode of the crane 100 to power synchronization mode. When the control mode of the crane 100 is set to power synchronization mode, the controller 70 performs the luffing synchronization control.

[0115] If the power synchronization mode condition is met (YES in step S11), the controller 70 sets the control mode of the crane 100 to the power synchronization mode (step S12) and performs luffing synchronization control, including the processing in steps S13 to S15. On the other hand, if the power synchronization mode condition is not met (NO in step S11), the controller 70 does not perform the luffing synchronization control.

[0116] The aforementioned power synchronization mode conditions may, for example, be the condition that the luffing operation lever 55A is being operated (Condition 1). Alternatively, the power synchronization mode conditions may, for example, be the condition that the luffing operation lever 55A is being operated while the assist mode switch 91, described later, is ON (Condition 2). Alternatively, the power synchronization mode conditions may, for example, be the condition that the luffing operation lever 55A is being operated while the opening / closing mode switch 90, described later, is OFF (Condition 3). Alternatively, the power synchronization mode conditions may, for example, be the condition that the luffing operation lever 55A is being operated while the opening / closing mode switch 90 is OFF and the assist mode switch 91 is ON (Condition 4). However, the power synchronization mode conditions may include other conditions in addition to Condition 1, Condition 2, Condition 3, or Condition 4. The condition that the luffing operation lever 55A is being operated, which is included in Condition 1, Condition 2, Condition 3, and Condition 4 respectively, is a condition for determining whether the luffing member 104 is performing a luffing operation.

[0117] In step S13, the controller 70 controls the first distance change ΔL top-m and the second distance change ΔL top-a Perform the calculation.

[0118] In step S14, the controller 70 controls the first distance change ΔL top-m and the second distance change ΔL top-a Based on this, a correction amount (e.g., distance change deviation er) is calculated to maintain the open / closed state of buckets 13, 13.

[0119] In step S15, the controller 70 maintains the open / closed state of the buckets 13, 13 by adjusting one or both of the payout amounts of the first winch rope R1 and the second winch rope R2 based on the calculated correction amount. The controller 70 repeats the process from step S11 onwards.

[0120] [Second Embodiment] Figure 9 is a block diagram showing the controller 70 and related main components of the bucket control device 200 according to the second embodiment of this disclosure. The basic configuration of the bucket control device 200 and the crane 100 according to the second embodiment is the same as the configuration of the bucket control device 200 and the crane 100 according to the first embodiment, which were described with reference to Figures 1 to 8. The bucket control device 200 according to the second embodiment differs from the first embodiment in that it selects one mode from a predetermined number of modes based on predetermined conditions and sets the control mode of the crane 100 to the selected mode. Therefore, in the following, we will mainly describe the configurations of the bucket control device 200 and the crane 100 according to the second embodiment that differ from the first embodiment, and will omit the description of the configurations that are the same as the first embodiment.

[0121] As shown in Figure 9, the crane 100 according to the second embodiment includes an operator setting device 21, a first drum rotation detector 81, a second drum rotation detector 82, a luffing member angle detector 22, at least one mode switch, lever input detectors 51B, 53B, 55B, pedal input detectors 52B, 54B, load value detector 94, and a setting memory device 95 (previous setting memory device).

[0122] The first drum rotation detector 81, the second drum rotation detector 82, the undulation member angle detector 22, the lever input detectors 51B, 53B, 55B, and the pedal input detectors 52B, 54B are the same as those described above for the first embodiment.

[0123] The operator setting device 21 is an input device for the operator to input various settings necessary for the operation of the crane 100 according to the second embodiment. The operator setting device 21 receives input from the operator for making the various settings. The operator setting device 21 may be located, for example, inside the cabin 114. The operator setting device 21 may include, for example, a monitor touch panel. The various settings may include, for example, specification data for the main components constituting the construction machine, such as the luffing member 104, winch drums DR1 and DR2, and bucket device 10. The various settings may include, for example, the winding state of the winch ropes of the winch drums DR1 and DR2 at the start of work (for example, a value indicating how much of the winch rope is wound on the winch drum).

[0124] The at least one mode switch may include, for example, an on / off mode switch 90 and an assist mode switch 91.

[0125] The load value detector 94 detects a load value that correlates with the bucket weight, which is the weight of the bucket device 10. The load value detector 94 may be, for example, a load cell. The load value detector 94 may be attached to the lower spreader 110, for example, as shown in Figure 1, to detect the load value acting on the luffing rope R3. However, the mounting position of the load value detector 94 is not limited to the lower spreader 110. For example, the load value detector 94 may be attached to the upper spreader 109 to detect the load value acting on the luffing rope R3. Alternatively, the load value detector 94 may detect the load value acting on the guy line 108.

[0126] The setting memory 95 stores the weight of the bucket device 10 calculated by the bucket weight calculation unit 73, which will be described later. Specifically, the setting memory 95 may store the bucket weight as the previous setting value when the power to the controller 70 is turned off. Then, in the next operation, the controller 70 may use the previous setting value stored in the setting memory 95 as the bucket weight.

[0127] In the second embodiment, the controller 70 sets the control mode of the crane 100 to one of a plurality of modes based on a preset determination condition. In this embodiment, the plurality of control modes may include an assist mode and a non-assist mode. The assist mode includes a bucket opening / closing mode, a power synchronization mode, and a free synchronization mode.

[0128] The assist mode is a control mode in which the controller 70 performs assist control to enable the operator to make the bucket device 10 perform predetermined operations with simple operations. The non-assist mode is a control mode in which the above-mentioned assist control is not performed (no-control mode).

[0129] In this embodiment, the controller 70 sets the control mode to assist mode when the assist mode switch 91 is ON, and sets the control mode to non-assist mode when the assist mode switch 91 is OFF. In assist mode, the controller 70 sets the control mode to bucket opening / closing mode when the opening / closing mode switch 90 is ON, and sets the control mode to synchronized control mode when the opening / closing mode switch 90 is OFF. The synchronized mode includes power synchronized mode and free synchronized mode. Specifically, these are as follows.

[0130] The assist mode switch 91 is a switch for setting the control mode of the crane 100 to assist mode. When the assist mode switch 91 is turned on by the operator, it inputs an on command signal corresponding to the on operation to the controller 70, and the controller 70 sets the control mode to assist mode. If the assist mode switch 91 is not turned on, the controller 70 does not set the control mode to assist mode, but sets the control mode to another predetermined control mode (for example, non-assist mode).

[0131] The opening / closing mode switch 90 is a switch for setting the control mode of the controller 70 to the bucket opening / closing mode. When the control mode is set to assist mode and an ON operation for the bucket opening / closing mode is given to the opening / closing mode switch 90 by the operator, the opening / closing mode switch 90 inputs an ON command signal corresponding to the ON operation to the controller 70, and the controller 70 sets the control mode to the bucket opening / closing mode. When the control mode is set to assist mode and the ON operation is not given to the opening / closing mode switch 90, the controller 70 sets the control mode to synchronized control mode.

[0132] As described above, in this embodiment, the tuning mode includes a power tuning mode and a free tuning mode. The controller 70 sets the control mode to either the power tuning mode or the free tuning mode by performing calculation processing as shown in the flowchart in Figure 10, for example.

[0133] The bucket opening / closing mode is a control mode that allows the bucket device 10 to perform operations, including changing the open / closed state of a pair of buckets 13, 13, based on a specific pre-set operation. When the control mode is set to bucket opening / closing mode, the controller 70 performs non-synchronized control such as bucket stationary closing control, bucket stationary opening control, and excavation control, which will be described later.

[0134] When the control mode is set to power synchronization mode, the controller 70 performs the same elevation synchronization control as in the first embodiment or the main auxiliary synchronization control described later. When the control mode is set to free synchronization mode, the controller 70 performs the free synchronization control described later.

[0135] The controller 70 comprises a computer including a processing unit and memory. In the second embodiment shown in Figure 9, the controller 70 includes a lifting value calculation unit 71, an operation state determination unit 72, a bucket weight calculation unit 73, a wire tension determination unit 74, an assist mode determination unit 75, a target pilot pressure calculation unit 76, and a valve command current value calculation unit 77. Each of these functions is realized by the processing unit executing a control program stored in the memory.

[0136] The lifting height calculation unit 71 calculates the lifting height of the first winch rope R1 and the lifting height of the second winch rope R2, respectively, based on the setting data input from the operator setting device 21 to the controller 70, the detection results input from the drum rotation detectors 81 and 82 to the controller 70, and the luffing angle θ of the luffing member 104 input from the luffing member angle detector 22 to the controller 70.

[0137] The setting data input from the operator setting device 21 to the controller 70 may include, for example, specification data including the length of the luffing member 104, and may further include data relating to the relative position of the first winch drum DR1 with respect to the specific part 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.

[0138] The lifting height values ​​of the winch ropes (the lifting height values ​​of the first winch rope R1 and the second winch rope R2, respectively) are values ​​that take into account the effect of changes in the elevation angle θ. When the position of a predetermined part of the winch rope in the reference state is taken as the reference (zero position), the amount of change in the position of the predetermined part of the winch rope relative to this reference is called the lifting height value of the winch rope. The predetermined part of the winch rope may be, for example, the tip of the winch rope, or it may be any other part of the winch rope. The reference state is, for example, when the winch rope is extended a predetermined length from the winch drum, and the elevation angle θ of the elevation member 104 is a predetermined angle θs.

[0139] More specifically, the reference state may be, for example, the state in which the winch rope is fully extended from the winch drum and the luffing angle θ of the luffing member 104 is 45 degrees. In this case, the lifting value of the first winch rope R1 is as follows. That is, the position of the tip of the first winch rope R1 in the state in which the first winch rope R1 is fully extended from the first winch drum DR1 and the luffing angle θ of the luffing member 104 is 45 degrees is used as the reference, and the lifting value of the first winch rope R1 is the amount of change in the position of the tip of the first winch rope R1 relative to this reference. Similarly, the lifting value of the second winch rope R2 is as follows. In other words, the lifting height of the second winch rope R2 is the amount of change in the position of the tip of the second winch rope R2 relative to the reference position when the second winch rope R2 is fully extended from the second winch drum DR2 and the luffing angle θ of the luffing member 104 is 45 degrees.

[0140] The lifting height 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 angle θ of the luffing member 104. Similarly, the lifting height 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 angle θ of the luffing member 104.

[0141] 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 drum rotation detectors 81 and 82, and the luffing angle θ of the luffing member 104 input to the controller 70 from the luffing member angle detector 22, to calculate the lifting height values ​​of the first winch rope R1 and the second winch rope R2, respectively.

[0142] The controller 70 is located at a first distance L relative to the reference state. top-m The lifting height value Lh1 of the first winch rope R1 may be calculated based on the change in ΔL1, the change in the height position of the upper end P1 of the luffing member 104 relative to the reference state ΔH1, and the change in the amount of the first winch rope R1 extended relative to the reference state ΔR1. The controller 70 may calculate the lifting height value Lh1 of the first winch rope R1 using, for example, the following equation (4).

[0143] The lifting height of the first winch rope R1 is Lh1 = -(ΔL1 + ΔH1 + ΔR1) (4)

[0144] Similarly, the controller 70 controls the second distance L relative to the reference state. top-a The lifting height value Lh2 of the second winch rope R2 may be calculated based on the change in ΔL2, the change in the height position of the upper end P2 of the luffing member 104 relative to the reference state ΔH2, and the change in the amount of the second winch rope R2 extended relative to the reference state ΔR2. The controller 70 may calculate the lifting height value Lh2 of the second winch rope R2 using, for example, the following equation (5).

[0145] The lifting height of the second winch rope R2 is Lh2 = -(ΔL2 + ΔH2 + ΔR2) (5)

[0146] Here, we assume that the upper end P1 and the upper end P2 of the luffing member 104 are at the same height, and that the amount of the first winch rope R1 and the amount of the second winch rope R2 extended are both zero during the process in which the luffing angle θ of the luffing member 104 changes from θ1 to θ2. In this case, the deviation er' between the lifting height Lh1 of the first winch rope R1 and the lifting height Lh2 of the second winch rope R2 when the luffing angle θ changes from θ1 to θ2 can be expressed, for example, by the following equation (6). That is, when the luffing angle θ of the luffing member 104 changes from θ1 to θ2 with the first winch drum DR1 and the second winch drum DR2 stopped, the deviation er' between the lifting height Lh1 of the first winch rope R1 and the lifting height Lh2 of the second winch rope R2 can be expressed, for example, by the following equation (6).

[0147] er' = ΔL2 - ΔL1 (6)

[0148] Therefore, in this second embodiment, the controller 70 may calculate the deviation er' and perform the elevation synchronization control based on it.

[0149] Furthermore, when the first winch drum DR1 and the second winch drum DR2 are stopped and the elevation angle θ of the elevation member 104 changes from θ1 to θ2, the absolute value of the deviation er'|er'| between the change in the lifting height Lh1 of the first winch rope R1 and the change in the lifting height Lh2 of the second winch rope R2 will be the same as the absolute value of the distance change deviation er|er| described above.

[0150] Therefore, in this second embodiment, the controller 70 may calculate the distance change deviation er in the same manner as in the first embodiment, and perform the same elevation synchronization control as in the first embodiment based on the distance change deviation er.

[0151] The operation state determination unit 72 determines the lever operation state for the first winch operation lever 51A and the second winch operation lever 53A, respectively, based on the detection results input to the controller 70 from the first lever input detector 51B and the second lever input detector 53B. Specifically, the operation state determination unit 72 determines, based on the detection results, whether the lever operation state is a hoisting operation state, a lowering operation state, or a neutral state.

[0152] The operation state determination unit 72 may determine that the lever operation state is a hoisting operation state if the amount of hoisting operation applied to each of the first winch operating lever 51A and the second winch operating lever 53A is equal to or greater than a predetermined threshold. The operation state determination unit 72 may also determine that the lever operation state is a lowering operation state if the amount of lowering operation applied to each of the first winch operating lever 51A and the second winch operating lever 53A is equal to or greater than a predetermined threshold.

[0153] The operation state determination unit 72 may determine the pedal operation state for the first brake operation pedal 52A and the second brake operation pedal 54A, respectively, based on the detection results input to the controller 70 from the first pedal input detector 52B and the second pedal input detector 54B. Specifically, the operation state determination unit 72 may determine, based on the detection results, whether the pedal operation state is a brake state or a free state.

[0154] The bucket weight calculation unit 73 calculates the weight of the bucket device 10. Specifically, the bucket weight calculation unit 73 may calculate the weight of the bucket device 10 based on the load value detected by the load value detector 94 at the time an operator performs an input operation on the bucket weight setting device (not shown in the figure). The bucket weight setting device may include, for example, a touch panel on a monitor.

[0155] The wire tension determination unit 74 determines whether the bucket device 10 is touching the ground or not based on the load value detected by the load value detector 94 and the bucket weight. For example, the wire tension determination unit 74 may determine that the bucket device 10 is touching the ground if the load value detected by the load value detector 94 at that time is less than or equal to a predetermined first threshold that is less than the bucket weight (for example, less than or equal to 30% of the bucket weight). For example, the wire tension determination unit 74 may determine that the bucket device 10 is not touching the ground if the load value detected by the load value detector 94 at that time is greater than or equal to a predetermined second threshold that is greater than the first threshold (for example, more than or equal to 70% of the bucket weight).

[0156] The assist mode determination unit 75 determines the control mode of the crane 100. Specifically, the assist mode determination unit 75 may determine whether the control mode is bucket opening / closing mode, power synchronization mode, free synchronization mode, or non-assist mode (no control mode) by performing calculation processing as shown in the flowchart of Figure 10, which will be described later.

[0157] The target pilot pressure calculation unit 76 recognizes the current control mode (bucket opening / closing mode, power synchronization mode, free synchronization mode, or non-assist mode) based on the determination result made by the assist mode determination unit 75, and calculates the target pilot pressure to be input to the first control valve 32 and the second control valve 33, respectively, according to the control mode. For example, when the luffing operation lever 55A receives a luffing operation, the control mode is set to power synchronization mode, and the target pilot pressure calculation unit 76 calculates the target pilot pressure to be input to the first control valve 32 and the second control valve 33, respectively, based on the luffing angle θ of the luffing member 104.

[0158] The valve command current value calculation unit 77 calculates command current values ​​to be input to the first dispensing proportional valve 61A, the first retracting proportional valve 61B, the second dispensing proportional valve 63A, and the second retracting proportional valve 63B, respectively, based on the target pilot pressure calculated by the target pilot pressure calculation unit 76. Specifically, for example, the valve command current value calculation unit 77 may calculate the command current values ​​using the target pilot pressure calculated by the target pilot pressure calculation unit 76 and a map representing the relationship between the target pilot pressure and the command current values, as shown in Figure 12, for example. The controller 70 inputs the calculated command current values ​​to the proportional valves 61A, 61B, 63A, and 63B, respectively. The controller 70 may also calculate command current values ​​to be input to various switching valves included in the hydraulic circuit of the crane 100 and input the calculated command current values ​​to the switching valves.

[0159] Figure 10 is a flowchart showing an example of the calculation process performed by the controller 70 according to the second embodiment.

[0160] In step S101, the controller 70 determines whether predetermined bucket opening / closing mode conditions are met. The bucket opening / closing mode conditions are conditions for determining whether or not to set the control mode to bucket opening / closing mode. Specifically, for example, the bucket opening / closing mode conditions may be that the opening / closing mode switch 90 is ON and the luffing operation lever 55A is not operated.

[0161] If the bucket opening / closing mode conditions are met (YES in step S101), specifically, if the opening / closing mode switch 90 is ON and the luffing operation lever is not operated, the controller 70 sets the control mode to the bucket opening / closing mode (step S102). If the bucket opening / closing mode conditions are not met (NO in step S101), the controller 70 performs the process in step S103.

[0162] In step S103, the controller 70 determines whether a predetermined power synchronization mode condition is met. The power synchronization mode condition is a condition for determining whether or not to set the control mode to power synchronization mode. The power synchronization mode condition may be, for example, the condition that the first winch operating lever 51A or the luffing operating lever 55A is being operated.

[0163] If the power synchronization mode condition is met (YES in step S103), specifically, if the first winch operating lever 51A or the luffing operating lever 55A is operated, the controller 70 sets the control mode to power synchronization mode (step S104). If the power synchronization mode condition is not met (NO in step S103), the controller 70 performs the process in step S105.

[0164] In step S105, the controller 70 determines whether a predetermined free-synchronization mode condition is met. The free-synchronization mode condition is a condition for determining whether or not to set the control mode to free-synchronization mode. The free-synchronization mode condition may be, for example, a neutral free mode and a main hoist free operation. Specifically, the crane 100 has a neutral free mode and a neutral brake mode as control modes. In neutral brake mode, even when the brake pedal is released and not pressed, the winch drum remains connected to the power side. That is, the winch drum will not move without lever operation. By pressing the free switch while the brake pedal is pressed in neutral brake mode, the system enters neutral free mode. By releasing the brake pedal, the winch drum is disconnected from the power side, and the drum rotates due to gravity. "Main hoist free operation" refers to a state where the brake pedal is released, and the brake pressure is such that the drum is disconnected from the power side, meaning the winch drum is driven by the brake pedal. This is detected by a pressure sensor that detects pedal pressure.

[0165] If the free tuning mode condition is met (YES in step S105), specifically, in neutral free mode and when there is a main winding free operation, the controller 70 sets the control mode to free tuning mode (step S106). If the free tuning mode condition is not met (NO in step S105), the controller 70 sets the control mode to non-assist mode (no control mode) (step S107).

[0166] [Power synchronization mode] First, let me explain the power synchronization mode.

[0167] In the second embodiment, when the power synchronization mode condition is met (YES in step S103 of Figure 10), the controller 70 transitions to the power synchronization mode and performs luffing synchronization control similar to the first embodiment or the main auxiliary synchronization control described later. Specifically, when the first winch operating lever 51A is operated, the controller 70 sets the control mode to the power synchronization mode and performs the main auxiliary synchronization control described later. When the luffing operation lever 55A is operated, the controller 70 sets the control mode to the power synchronization mode and performs the luffing synchronization control.

[0168] [Undulation synchronization control] The luffing synchronization control is the same as in the first embodiment. That is, in this luffing synchronization control, the controller 70 adjusts one or both of the payout amounts of the first winch rope R1 and the second winch rope R2 in accordance with the angle change of the luffing member 104 to maintain the open and closed state of the buckets 13, 13. Specifically, it is as follows.

[0169] In step S103 of the flowchart in Figure 10, if the luffing operation lever 55A is operated, the controller 70 sets the control mode to power synchronization mode and performs the luffing synchronization control. The controller 70 performs calculation processing for the luffing synchronization control as shown in the flowchart in Figure 11, for example.

[0170] In step S21, the controller 70 determines whether the elevation control lever 55A is being operated. If the elevation control lever 55A is being operated (YES in step S21), the controller 70 determines the first distance change amount ΔL top-m and the second distance change ΔL top-a The calculation is performed (step S22). If the luffing lever 55A is not operated (NO in step S21), more specifically, if neither the luffing lever 55A nor the first winch operating lever 51A is operated, the controller 70 performs the process of step S105 in the flowchart of Figure 10.

[0171] In step S23, the controller 70 controls the first distance change ΔL top-m and the second distance change ΔL top-a Based on this, a correction amount (for example, the distance change deviation er described in the first embodiment) is calculated to maintain the open / closed state of the buckets 13, 13.

[0172] In step S24, the controller 70 maintains the open / closed state of the buckets 13, 13 by adjusting one or both of the payout amounts of the first winch rope R1 and the second winch rope R2 based on the calculated correction amount. The controller 70 then repeats the process from step S21 onward.

[0173] [Main and complementary synchronization control] Next, the main auxiliary synchronization control will be explained. In step S103 of the flowchart in Figure 10, if the first winch operating lever 51A is operated, the controller 70 sets the control mode to power synchronization mode and performs the following main auxiliary synchronization control. The 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.

[0174] The main auxiliary synchronization control includes opening down control, closing down control, opening up control, and closing up control. 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 a first lever operation applied to the first winch operating lever 51A.

[0175] Specifically, when an unwinding operation is applied to the first winch operating lever 51A, the controller 70 sets the control mode to power-synchronized mode and performs the following opening-down control or closing-down control. In 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 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.

[0176] Furthermore, when a winding operation is applied to the first winch operating lever 51A, the controller 70 sets the control mode to power synchronization mode and performs the following opening-up control or closing-up control. In 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 closing-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 closed state of the bucket device 10.

[0177] [Bucket opening / closing mode] Next, we will explain the bucket opening and closing modes.

[0178] When the control mode is set to bucket opening / closing mode, the controller 70 performs non-synchronized control such as bucket stationary closing control, bucket stationary opening control, and excavation control.

[0179] Bucket stationary closing control is a control method used in the bucket opening / closing mode to close the buckets 13, 13 while the bucket device 10 is stationary in the air. In bucket stationary closing control, the second winch operating lever 53A is in the neutral position, and the second brake operating pedal 54A is pressed down, meaning that the second winch drum DR2 is braked to prevent its rotation, and a winding operation is applied to the first winch operating lever 51A. This allows the first winch rope to be wound up without paying out or winding up the second winch rope, and the bucket device 10 can be operated in the closing direction while maintaining the height of the bucket device 10 in the air.

[0180] Bucket stationary opening control is a control method used in bucket opening / closing mode to open and operate the buckets 13, 13 while the bucket device 10 is stationary in the air. In bucket stationary opening control, with the second winch operating lever 53A in the neutral position and the second brake operating pedal 54A pressed down, that is, with the second winch drum DR2 being braked to prevent its rotation, the first brake operating pedal 52A is operated to reduce (weaken) the first brake force. This allows the first winch rope R1 to be paid out and the tension of the first winch rope R1 to be released without paying out or retracting the second winch rope, and the bucket device 10 can be operated in the opening direction while maintaining the height of the bucket device 10 in the air. This air-opening operation is used, for example, in soil removal work, where the object to be transported, such as soil and sand held in the closed bucket device 10, is removed onto the destination (e.g., the bed of a truck).

[0181] Excavation control is the control that causes the bucket device 10 to perform an excavation operation in the bucket opening and closing mode. In excavation control, the second winch drum DR2 is left free, and the first winch rope R1 is wound up with the first winch drum DR1, thereby loosening the tension on the second winch rope R2 and causing the bucket device 10 to perform the closing operation. As a result, during the process of closing the bucket device 10 in the excavation operation, the bucket device 10 sinks down as the material to be excavated, such as soil, is excavated, allowing more material to be stored inside the bucket device 10.

[0182] [Free tune mode] Next, I will explain the free tuning mode.

[0183] When the control mode is set to free synchronization mode, the controller 70 performs free synchronization control to adjust the first braking force and the second braking force of the first clutch brake 40 and the second clutch brake 40 based on the amount of operation of the first pedal applied to the first brake operation pedal 52A (pedal operation amount).

[0184] The controller 70 adjusts the first brake force and the second brake force. When the control mode is set to free synchronization mode, a first brake operation that reduces the first brake force is applied to the first brake operation pedal 52A, and the bucket device 10 is in the open state, the controller 70 performs the following opening down control. In this opening down control, the controller 70 adjusts the first brake force and the second brake force so that the bucket device 10 descends by its own weight while maintaining the open state of the bucket device 10. Such opening down control performed in response to an operation applied to the brake operation pedal is an example of free synchronization control.

[0185] Furthermore, when the control mode is set to free synchronization mode, a first brake operation that reduces the first brake force is applied to the first brake pedal 52A, and the bucket device 10 is in the closed state, the controller 70 performs the following closing down control. In this closing down control, the controller 70 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. This closing down control, which is performed in response to an operation applied to the brake pedal, is an example of free synchronization control. A first brake operation that reduces the first brake force is, for example, an operation that reduces the amount of pedal operation (depression amount) applied to the first brake pedal 52A.

[0186] The controller 70 may determine the open or closed state of the bucket device 10. That is, the controller 70 may determine whether the bucket device 10 is in an open state or a closed state. The controller 70 may determine the open or closed state of the bucket device 10 based on a first rotation amount ωm and a second rotation amount ωa.

[0187] This disclosure is not limited to the embodiments described above. This disclosure includes, for example, the following forms:

[0188] (A) Regarding the specifications of the crane The crane according to the embodiment shown in Figure 1 does not have a jib and struts, but the specifications of the crane are not limited to those shown in Figure 1. The crane according to this disclosure may be a luffing crane equipped with a jib, front struts and rear struts, or it may be a fixed jib crane equipped with a jib and one strut. Furthermore, the crane according to this disclosure may be a crane equipped with a mast instead of a gantry (for example, a large crane).

[0189] In the above embodiment, 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.

[0190] (B) Regarding winch ropes and winch drums In the above embodiment, the first winch rope R1 is the opening / closing rope, the second winch rope R2 is the support rope, the first winch drum DR1 is the opening / closing drum, and the second winch drum DR2 is the support drum. However, these configurations may be reversed. That is, the first winch rope R1 may be the support rope, the second winch rope R2 may be the opening / closing rope, the first winch drum DR1 may be the support drum, and the second winch drum may be the opening / closing drum.

[0191] (C) About the bucket control device In the above embodiment, the bucket control device 200 is provided on the crane 100, but 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.

[0192] (D) Regarding the operating device The operating devices relating to this disclosure may be appropriately selected depending on the type of first and second winches and their drive devices. For example, the lever input detectors 51B and 53B of the first winch operating device 51 and the second winch operating device 53 shown in Figures 2 and 3, and the pedal input detectors 52B and 54B of the first brake operating device 52 and the second brake operating device 54, may each be replaced with a device that includes a remote control valve that outputs pilot pressure corresponding to the operation and a pressure sensor that detects said pilot pressure. In this case, proportional valves 61A and 61B may be interposed between the remote control valve of the first winch operating device 51 and a pair of pilot ports of the first control valve, respectively, and proportional valves 63A and 63B may be interposed between the remote control valve of the second winch operating device 53 and a pair of pilot ports of the second control valve 33, respectively. Furthermore, the proportional valve 62 may be interposed between the remote control valve of the first brake operating device 52 and the first clutch brake 40, and the proportional valve 64 may be interposed between the remote control valve of the second brake operating device 54 and the second clutch brake 40.

[0193] (E) About winches The first and second winches relating to this disclosure may be, for example, electric winches. In this case, the hydraulic circuit shown in Figure 3 can be replaced with an electrical circuit (for example, a circuit including an inverter) that drives the electric winch. [Explanation of Symbols]

[0194] 10: Bucket device 13: Bucket 55:Luffing operation device 55A: Lever for controlling elevation 55B: Elevation lever input detector 70: Controller 100: Crane 101: Lower body 102: Upper rotating body 104: Uneven member 200: Bucket control device DR1: First winch drum DR2: Second winch drum DR3: Luffing Winch Drum R1: First winch rope R2: Second winch rope R3: Relief rope L top-m :1st distance L top-a :2nd distance ΔL top-m : First distance change ΔL top-a : Second distance change er: Distance change deviation θ: undulation angle P1: First part of the raised member P2: Second part of the raised member

Claims

1. A bucket control device for a construction machine comprising: a machine body; a luffing member that can be raised and lowered relative to the machine body; a first winch drum for paying out and reeling in a first winch rope hanging from the luffing member; a second winch drum positioned differently from the first winch drum for paying out and reeling in a second winch rope hanging from the luffing member; and a bucket device to which the first winch rope and the second winch rope are connected, and which has a bucket that can be opened and closed in accordance with the operation of the first winch drum and the operation of the second winch drum, wherein A bucket control device comprising a controller that performs luffing synchronization control to maintain the open / closed state of the bucket by adjusting one or both of the payout amounts of the first winch rope and the second winch rope in accordance with the angle change of the luffing member during the luffing operation of the luffing member.

2. The bucket control device according to claim 1, wherein the controller adjusts either or both the payout amount of the first winch rope and the payout amount of the second winch rope based on the amount of change of a first distance from the first winch drum to a predetermined first part of the luffing member, which changes in accordance with the angle change, and the amount of change of a second distance from the second winch drum to a predetermined second part of the luffing member, which changes in accordance with the angle change.

3. The construction machine further comprises a luffing control device which is an operating device that receives luffing operations for luffing the luffing member, The bucket control device according to claim 1, wherein the controller performs luffing synchronization control when the luffing operation device receives the luffing operation.

4. The machine body and, The aforementioned undulating member and, The first winch drum and, The aforementioned second winch drum, The aforementioned bucket device, A construction machine comprising a bucket control device according to any one of claims 1 to 3.

5. A method for maintaining the open / closed state of a bucket using a bucket control device according to any one of claims 1 to 3, A method for maintaining the open / closed state of a bucket, comprising the controller adjusting one or both of the payout amounts of the first winch rope and the second winch rope in accordance with the change in angle of the luffing member during the luffing operation of the luffing member to maintain the open / closed state of the bucket.

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