crane

Abstract

To suppress fluctuation in derricking angle of a boom caused by a turning angle change of the boom.SOLUTION: A crane 1 comprises: a lower travelling body 2; an upper turning body 3 rotatably provided in the lower traveling body 2; and a boom 4 derrickingly provided in the upper turning body 3. Auxiliary control of derricking control of the boom 4 is executed according to the angle of the boom 4 changed depending on a turning angle. For example, the auxiliary control may include at least motion control for reducing the work radius of the boom 4 or motion control for suppressing fluctuation in angle of the boom 4 from a turning start of the upper turning body 3.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a crane. [Background technology]

[0002] In a conventional crane, when a load is being transported, a rotation curve is displayed to the worker, indicating the workable range with the crane at the center (see, for example, FIG. 2 of Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-219932 Summary of the Invention [Problem to be solved by the invention]

[0004] The rigidity of the crane's undercarriage against the load received from the upper rotating body varies depending on the rotation angle, so when the rotation angle of the upper rotating body changes, the amount of deflection of the undercarriage also changes, which can cause the boom hoisting angle (the angle at which the boom is raised or lowered relative to the ground) to fluctuate, resulting in a change in the working range. However, the crane in Patent Document 1 does not take into consideration fluctuations in the boom hoisting angle due to differences in the rigidity of the lower traveling structure at each swing angle.

[0005] An object of the present invention is to suppress the influence of fluctuations in the boom hoisting angle caused by changes in the rotation angle of the upper rotating body. [Means for solving the problem]

[0006] The present invention provides a lower running body; an upper rotating body rotatably provided on the lower traveling body; a boom provided on the upper rotating body so as to be able to be raised and lowered; A crane comprising: the lower traveling body includes a main body and crawlers disposed on both left and right sides of the main body and driven to rotate; performing a boom-raising-related operation for raising and lowering the boom in accordance with a rotation angle of the upper rotating body relative to the lower traveling body; The boom hoisting-related operation includes control for suppressing fluctuations in the boom hoisting angle from the start of rotation of the upper rotating body based on the rotation angle and the tilt direction and angle of the plane on which the crane is placed. , and is structured as follows. [Effects of the Invention]

[0007] According to the present invention, it is possible to suppress the influence of fluctuations in the boom hoisting angle caused by changes in the rotation angle of the upper rotating body. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a side view of a crane according to an embodiment of the present invention. [Figure 2] FIG. 2 is a block diagram showing the configuration of a crane control device and its peripherals. [Figure 3] FIG. 1 is an explanatory diagram showing a crane 1 in a schematic plan view. [Figure 4] 10 is a flowchart of assist control for hoisting control. DETAILED DESCRIPTION OF THE INVENTION

[0009] [Crane outline] Figure 1 is a side view of crane 1. Crane 1 is a so-called mobile crawler crane. In describing crane 1, the front-rear and left-right directions as seen from the lower running structure 2, which is the crane body, will be described as the front-rear and left-right directions of crane 1. Unless otherwise specified, the directions of each part will be described assuming that the lower running structure 2 is in a state where the front-rear direction is aligned with that of the upper rotating structure 3 (reference position). In addition, in the following explanation, it is assumed that the crane 1 is located on a horizontal plane, and when referring to a "plan view," it refers to a state viewed from a direction perpendicular to the horizontal plane on which the crane 1 is located, i.e., a vertical direction.

[0010] As shown in Figure 1, the crane 1 is composed of a self-propelled crawler-type lower running body 2, an upper rotating body 3 rotatably mounted on the lower running body 2, and a boom 4 attached to the front side of the upper rotating body 3 so that it can be raised and lowered.

[0011] The lower traveling body 2 includes a main body 21 and crawlers 22 provided on both the left and right sides of the main body 21. The left and right crawlers 22 are each rotationally driven by a traveling hydraulic motor (not shown).

[0012] A boom 4 is attached so as to be able to be raised and lowered to the front side of the upper rotating body 3. A sheave 43 that guides the hoisting rope 32 is rotatably attached to the upper end of the boom 4 near the tip thereof. Further, a lower end of a mast 31 is supported on the upper rotating body 3 rearward of the boom 4. The upper rotating body 3 is rotated around a vertical axis relative to the lower traveling body 2 by a hydraulic motor for rotation (not shown).

[0013] A counterweight 5 is attached to the rear of the upper rotating body 3 to balance the weight of the boom 4 and the suspended load L. The number of counterweights 5 can be increased or decreased as needed.

[0014] A hoisting winch 42 that raises and lowers the boom 4 is disposed near the counterweight 5, and in front of it is a hoisting winch 36 that winds and unwinds the hoisting rope 32. The hoisting winch 36 uses a hoisting hydraulic motor (not shown) to wind and unwind the hoisting rope 32, and hoists and lowers the hook 34 and the load L. A cab 33 is disposed on the right front side of the upper rotating body 3.

[0015] The mast 31 is equipped with an upper spreader 35 at its upper end, and the upper spreader 35 is connected to one end of a pendant rope 44, the other end of which is connected to the upper end of the boom 4. A lower spreader (not shown) is provided below the upper spreader 35, and when a hoisting rope 37 is wound multiple times between them and reeled in or out by a hoisting winch 42, the distance between the upper spreader 35 and the lower spreader changes, causing the boom 4 to hoist. The hoisting winch 42 is driven by a hoisting hydraulic motor (not shown).

[0016] [Crane control system] A crane control device 60 is mounted on the cab 33 of the upper rotating body 3. Figure 2 is a block diagram showing the configuration of the control device 60 and its surroundings. The control device 60 is a control terminal mounted on the crane 1, and mainly controls various operations of the crane 1, such as traveling, rotation, raising and lowering of the boom 4, and hoisting and lowering of the load. The control device 60 includes a controller 61 that includes a processing unit having a CPU, ROM and RAM as storage devices, and other peripheral circuits. The controller 61 includes a software module of a hoisting auxiliary control unit 611, which performs hoisting-related operations of the boom 4, as will be described later. The hoisting auxiliary control unit 611 may also be configured from hardware.

[0017] The controller 61 is connected to an input unit 621 , a display device 622 , an alarm 623 , an operating lever 624 , and a memory 625 , which together constitute the control device 60 . Furthermore, the controller 61 is connected to a load cell 631 , a boom angle sensor 632 , a rotation amount sensor 633 , and a control valve 635 .

[0018] The input unit 621 is an input interface such as a touch panel, and outputs a control signal corresponding to an operation by an operator to the controller 61. The operator can operate the input unit 621 to input the length of the boom 4, the weight of the suspended load, and various other settings and inputs required for operation. The display device 622 is equipped with, for example, a touch panel display that is also used as the input unit 621, and displays information such as the weight of the load, the boom angle, and the rotation angle of the upper rotating body 3 on the display screen based on control signals output from the controller 61. The alarm device 623 issues an alarm based on a control signal output from the controller 61 .

[0019] The operation lever 624 is used to manually input, for example, operations to cause the crane 1 to perform various operations, and a control signal corresponding to the amount of operation of the operation lever 624 is input to the controller 61. For example, the operation lever 624 can be used to input operations for the traveling operation of the lower traveling body 2, the rotating operation of the upper rotating body 3, the raising and lowering operation of the boom 4, and the lifting and lowering operation of the suspended load.

[0020] The load cell 631 is attached to the end of the derricking rope 37, which is wound around the upper spreader 35 and the lower spreader multiple times, and detects the tension acting on the derricking rope 37 when the boom 4 is derricked, and outputs a control signal corresponding to the detected tension to the controller 61. The load cell 631 may be placed anywhere as long as it can indirectly measure the hoisting force of the boom 4. For example, it may be placed at an attachment position (not shown) of the pendant rope 44 at the tip of the boom 4 to detect the tension applied to the pendant rope 44.

[0021] 1, the boom angle sensor 632 is attached near the base end of the boom 4, detects the boom hoisting angle (hereinafter also referred to as the boom angle) of the boom 4, and outputs a control signal corresponding to the detected boom angle to the controller 61. An example of the boom angle sensor 632 is a sensor that uses a substance that is affected by gravity, such as a weight or a liquid surface, to detect the boom hoisting angle of the boom 4 relative to an absolute horizontal plane from the inclination direction relative to the direction of gravity as the boom angle. In principle, the crane 1 is installed on a horizontal plane, so even if the crane 1 is placed on an inclined plane, the boom angle sensor 632 detects the ground angle of the boom 4 with respect to the horizontal plane as the hoisting angle. The hoisting angle of the boom 4 with respect to the ground may also be detected as the boom angle.

[0022] The rotation amount sensor 633 is attached between the lower traveling body 2 and the upper rotating body 3, detects the rotation angle of the upper rotating body 3, and outputs a control signal corresponding to the detected rotation angle to the controller 61. The rotation amount sensor 633 detects, for example, the angle around the central axis of the vertical upper rotating body 3 as the rotation angle, and defines a state in which the front of the lower traveling body 2 and the front of the upper rotating body 3 are aligned as 0°.

[0023] The control valve 635 is composed of a plurality of valves that can be switched in response to a control signal from the controller 61 . For example, the control valve 635 includes a valve that controls the rotational drive of the left and right crawlers 22 of the lower traveling body 2, a valve that controls the rotational operation of the upper rotating body 3, a valve that controls the rotational drive of the hoisting winch 42, and a valve that controls the rotational drive of the hoisting winch 36.

[0024] [Elevation-related operations by the elevation control unit] FIG. 3 is an explanatory diagram showing a schematic plan view of the crane 1, illustrating the working range of the boom 4 in plan view when the upper rotating body 3 is rotating.

[0025] First, let us assume that the rigidity of each of the lower carriages 2 against the load of the load L (and the weight of the boom 4) is uniform regardless of the direction in which the upper rotating body 3 is facing. In this case, the working radius of the boom 4 (the distance from the center of rotation to the tip of the boom 4 in a plan view) is maintained constant when rotating without performing a hoisting operation. Therefore, the tip of the boom 4 rotates in a circular trajectory T1 shown in Figure 3.

[0026] However, it is practically difficult to make the rigidity of the lower traveling body 2 uniform in all directions, and the rigidity of the lower traveling body 2 differs for each swing angle of the upper swing body 3. For example, in a case where the lower traveling structure 2 has a structure in which long crawlers 22 are arranged on the left and right sides and the main body 21 is suspended from these crawlers 22, the rigidity may differ between a state in which the boom 4 faces left and right and a state in which the boom 4 faces forward and backward, depending on the structure of the lower traveling structure 2. In other words, the lower traveling structure 2 may bend for each swing angle, and the amount of change in the working radius may change. For example, if the rigidity of the boom 4 is lower when facing forward and backward than when facing left and right, when the boom 4 (upper rotating structure 3) is rotated from a state facing left or right to a state facing forward or backward, the lower running structure 2 will bend, and the boom hoisting angle with respect to the ground will become smaller. In this case, as shown in Figure 3, when the boom 4 is rotated from a state facing right to a state facing forward (in the direction in which the amount of bending of the lower running structure 2 increases), the working radius gradually increases and the boom 4 describes a substantially elliptical trajectory T2. In this way, if the working radius fluctuates due to turning, the path of the load L may deviate from prediction, making it difficult to maneuver.

[0027] For this reason, the hoisting auxiliary control unit 611 controls the hoisting winch 42 through the control valve 635 to make corrections to reduce changes in the hoisting angle of the boom 4, which changes depending on the rotation angle of the upper rotating body 3 relative to the lower running body 2, as a hoisting-related operation. Specifically, as a hoisting-related operation, the hoisting auxiliary control unit 611 controls the hoisting winch 42 via the control valve 635 so as to reduce fluctuations in the hoisting angle of the boom 4 when a change in the swivel angle causes fluctuations, based on the hoisting angle of the boom 4 at a predetermined swivel angle.

[0028] For example, in the example of Figure 3, when the upper rotating body 3 starts to rotate in a direction in which the boom 4 faces forward from a state in which the boom 4 faces to the right (when the upper rotating body 3 starts to rotate in a direction in which the amount of deflection of the lower running body 2 increases), the boom angle sensor 632 detects a decrease in the hoisting angle of the boom 4, and the hoisting auxiliary control unit 611 increases the hoisting angle of the boom 4 to suppress changes in the hoisting angle at the start of the rotation or drives the hoisting winch 42 to maintain the hoisting angle at the start of the rotation.

[0029] FIG. 4 is a flowchart specifically and in detail showing the process of the hoisting-related operation executed by the hoisting assistance control unit 611. As shown in the figure, when the operator inputs a command to rotate the upper rotating body 3 using the operation lever 624, the hoisting auxiliary control unit 611 stores the initial hoisting angle of the boom 4 detected at the start of the input (step S1). Note that the initial working radius may be calculated and stored instead of or together with the boom hoisting angle of the boom 4. The working radius can be calculated from pre-stored data on the length of the boom 4 and the boom hoisting angle of the boom 4 detected at the start of input.

[0030] Next, the hoisting auxiliary control section 611 determines whether or not the operator has input an operation to hoist the boom 4 using the operation lever 624 (step S3). If a hoisting operation has been input, the process returns to step S1, and the initial hoisting angle of the boom 4 is updated. It should be noted that while the hoisting operation is being input, the initial hoisting angle of the boom 4 is repeatedly updated, and when the input of the hoisting operation is completed, the hoisting angle at the time of completion is stored as the initial hoisting angle.

[0031] On the other hand, in step S3, if no boom 4 hoisting operation is input using the operating lever 624 or if the input has ended, the hoisting auxiliary control unit 611 determines whether the hoisting angle (or working radius) of the boom 4 currently detected by the boom angle sensor 632 has changed from the initial hoisting angle (or working radius) of the boom 4 stored in step S1 (step S5). If no change has occurred, the process returns to step S3, and it is determined whether or not an input for operating the boom 4 to raise or lower is made using the operating lever 624.

[0032] On the other hand, if the boom 4 hoisting angle (or working radius) currently detected by the boom angle sensor 632 has changed, the boom 4 is rotated in a direction that reduces the change, and the hoisting winch 42 is controlled so that the boom 4 suppresses any change from the initial hoisting angle or maintains the initial hoisting angle (step S7). Then, the process returns to step S3, and the processes of steps S1 to S7 are repeated until the input operation for rotating the upper rotating body 3 using the operating lever 624 is completed.

[0033] [Technical Effects of the Invention Embodiments] As described above, in the crane 1, the hoisting auxiliary control unit 611 performs hoisting-related operations for hoisting the boom 4 in accordance with the rotation angle of the upper rotating body 3 relative to the lower traveling body 2. This makes it possible to deal with changes in the working range of the boom 4 due to the rotation of the upper rotating body 3. Furthermore, it may be possible to suppress changes in the hoisting angle of the boom 4 due to the rotation of the upper rotating body 3 or the effects thereof.

[0034] Furthermore, if the lower running body 2 is designed so that its rigidity is equal in all directions within the swing angle range of the boom 4, or in both the left-right and front-to-back swing angles of the boom 4, in order to suppress fluctuations in the boom hoisting angle, it becomes difficult to design the working width and transport width required for the body of the crane 1 within an appropriate range. However, the hoisting-related operations of the hoisting auxiliary control unit 611 can reduce fluctuations in the hoisting angle of the boom 4 while relaxing the constraints on the design conditions required for the lower running body 2, making it possible to design the working width and transport width within an appropriate range.

[0035] In addition, in the lifting-related operations performed by the lifting auxiliary control unit 611, an operation is performed to raise the boom 4 at least when the upper rotating body 3 is rotated in a direction that increases the amount of deflection of the lower running body 2 due to the load from the upper rotating body 3 side. This makes it possible to prevent the expansion of the working radius (working range) of the boom 4 due to the rotation of the upper rotating body 3, and to move the load L and the hook 34 with high precision. It also makes it possible to prevent the impact on the surroundings caused by the movement paths of the load L and the hook 34 expanding outward.

[0036] Furthermore, the hoisting-related operations performed by the hoisting auxiliary control unit 611 include operation control to suppress fluctuations in the hoisting angle of the boom 4 from the start of rotation of the upper rotating body 3, and further to maintain the hoisting angle of the boom 4 at the start of rotation. Therefore, when the operator inputs a rotation operation for the upper rotating body 3, the hoisting angle of the boom 4 at the start of input is maintained or changes are suppressed, so the operation is performed as expected or close to expected, making it possible to improve accuracy and maneuverability.

[0037] Furthermore, when the hoisting auxiliary control unit 611 receives an operation command for the hoisting operation of the boom 4 while the upper rotating body 3 is rotating during the execution of a hoisting-related operation, it performs processing to stop the hoisting-related operation without proceeding to auxiliary control to suppress changes in the hoisting angle of the boom 4, as shown in step S3 in Figure 4 described above. Therefore, when the operator inputs an operation to raise or lower the boom 4, the boom 4 is raised or lowered in accordance with the operation, and the operation is performed according to the operator's wishes, making it possible to maintain good maneuverability.

[0038] Furthermore, as shown in the flow of steps S1 to S5 in Figure 4, after the hoisting auxiliary control unit 611 stops the hoisting-related operation by operating the hoisting operation of the boom 4, if the operation command for the hoisting operation of the boom 4 stops and the upper rotating body 3 is rotating, it resumes the hoisting-related operation. Therefore, the hoisting angle of the boom 4 adjusted by the operator's operation is maintained or changes are suppressed, making it possible to further improve maneuverability.

[0039] [others] The details shown in the above embodiment of the invention can be modified as appropriate without departing from the spirit of the invention. For example, in the above-described embodiment, the hoisting-related operations of the hoisting control were exemplified using a crawler crane as an example of a crane, but this is not limited to this and can be applied to mobile cranes such as cranes with tower attachments, wheel cranes, and truck cranes. Furthermore, the present invention is not limited to cranes equipped with hooks, but can also be applied to cranes that suspend attachments such as magnets and earth drill buckets.

[0040] In addition, while the example has been given assuming that the crane 1 is placed on a horizontal surface, the boom angle sensor 632 detects the hoisting angle of the boom 4 relative to the horizontal plane as the ground angle, the placement surface of the crane 1 is not limited to a strictly horizontal plane. For example, the crane 1 may be placed on an inclined surface within an allowable range relative to the horizontal plane. Furthermore, when the crane 1 is placed on an inclined surface, for example, the inclination direction and angle of the inclined surface may be determined and input to the controller 61, and the angle of the boom 4 may be corrected so that the hoisting angle of the boom 4 relative to the inclined surface remains constant or fluctuations are suppressed.

[0041] Furthermore, although the above example illustrates a control for correcting the hoisting angle of the boom 4 as a hoisting-related operation, the present invention is not limited to this. For example, if the amount of variation in the hoisting angle of the boom 4 according to the rotation angle of the upper rotating body 3 can be calculated or prepared as table data, and if the rotation angle range of the upper rotating body 3 is known in advance (for example, if the start and end points of the movement of the load L are determined), the hoisting-related operation of the hoisting control may be control to notify the operator, by display, audio, or the like, of the amount of change in the hoisting angle of the boom 4 that occurs between the start and end points of the rotation angle range of the upper rotating body 3 before the start of the rotation operation.

[0042] Furthermore, the operator may be able to select whether or not to perform the hoisting-related operations of the hoisting control in advance. Some operators may want to operate the boom 4 by their own operation without the hoisting angle of the boom 4 being corrected by the control of the controller 61, and this can be accommodated.

[0043] Furthermore, the above-described hoisting-related operations of the hoisting control are performed based on the hoisting angle at the start of the turning input operation, but the present invention is not limited to this. For example, the value of the hoisting angle of the boom 4 may be set in advance, and the hoisting-related operation of the hoisting control may be performed based on this value.

[0044] Furthermore, in the above-mentioned hoisting-related operations of the hoisting control, an example has been given of hoisting control in which fluctuations in the working radius based on the hoisting angle of the reference boom 4 are suppressed whether the radius is enlarged or reduced, but this is not limiting. For example, as the hoisting-related operation of the hoisting control, hoisting control in which fluctuations are suppressed may be performed only when the working radius based on the hoisting angle of the boom 4 is enlarged.

[0045] Furthermore, in the above embodiment, an example was given of a case in which the rigidity of the lower running body 2 differs depending on whether the boom 4 is oriented in the forward / backward direction or the left / right direction. However, if there is a variation in the rigidity of the lower running body 2 in at least any two different directions in which the boom 4 is oriented, the above-mentioned elevation-related operation of the elevation control can be applied.

[0046] Furthermore, the application of the hoisting-related operations of the hoisting control is not limited to cases where the operator in the cab 33 operates the crane 1. For example, the hoisting-related operations of the hoisting control are also effective when the crane 1 is remotely operated from the outside. [Explanation of symbols]

[0047] 1 crane 2 Undercarriage 3 Upper rotating body 4. Boom 21 Main body 22 Crawler 34 Hook 42 Hoisting winch 60 Control device 61 Controller 611 Elevation auxiliary control unit 621 Input section 622 Display device 624 Operating lever 632 Boom angle sensor 633 Turning amount sensor L Hanging load

Claims

1. a lower running body; an upper rotating body rotatably provided on the lower traveling body; a boom provided on the upper rotating body so as to be able to be raised and lowered; A crane comprising: the lower traveling body includes a main body and crawlers disposed on both left and right sides of the main body and driven to rotate; performing a boom-raising-related operation for raising and lowering the boom in accordance with a rotation angle of the upper rotating body relative to the lower traveling body; The boom hoisting-related operation includes control for suppressing fluctuations in the boom hoisting angle from the start of rotation of the upper rotating body based on the rotation angle and the inclination direction and angle of the surface on which the crane is placed.

2. The raising and lowering-related operation includes, at least, an operation for raising the boom when the upper rotating body is rotated in a direction in which the deflection amount of the lower traveling body increases due to a load from the upper rotating body side. The crane of claim 1.

3. The boom hoisting-related operation performs operational control to suppress fluctuations in the boom hoisting angle so as to maintain the boom hoisting angle based on the rotation angle at the start of rotation of the upper rotating body and the tilt direction and angle of the crane placement surface, and notifies the operator before starting the operational control of the amount of change in the boom hoisting angle that may occur between the known start point and end point of the rotation angle range. The crane according to claim 1 or 2.

4. When the crane receives an operation command for the boom hoisting operation while the upper rotating body is rotating, the crane stops the hoisting-related operation. The crane according to claim 1 or 2.

5. After the hoisting-related operation is stopped, the crane resumes the hoisting-related operation if the operation command for the boom hoisting operation is stopped and the upper rotating body is rotating. The crane of claim 3.

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