JP2018087069A - crane - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a crane capable of suppressing pitching of a lifted load after the completion of dynamic lift-off.SOLUTION: A crane 1 controlling the dynamic lift-off that lifts a lifted load W from the ground by controlling the rotation speed of a sub-winch 15 to be a prescribed speed or less, includes a band elimination processor 27 eliminating a signal in a specific frequency band from a winch driving signal for driving the sub-winch 15 and eliminates a signal in a frequency band inducing the pitching of the lifted load W from the winch driving signal by the band elimination processor 27 after raising the lifted load from the ground by controlling the dynamic lift-off so as to control the rotation speed of the sub-winch 15.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a crane. Specifically, the present invention relates to the rotational speed control of a winch after the ground cutting control of the crane.

  Conventionally, in a crane, when the ground cutting for lifting the suspended load from the ground is completed, the suspended load leaves the ground and is not restrained by the ground from the state where the suspended load is grounded and stopped. When the crane is given the natural frequency of the telescopic boom and wire rope, which is the main factor inducing the vertical swing of the suspended load to the telescopic boom and wire rope, with the suspended load not being restrained by the ground, Longitudinal swing of the suspended load is more likely to occur than when other frequencies are given. In view of this, a crane is known that controls a crane driving device so as to suppress the swing of the load to the minimum during and after the transfer of the load (suspended load) transferred by the crane. For example, as described in Patent Document 1.

  The crane described in Patent Document 1 occurs when a load suspended by a crane rope (wire rope) is transported by operating a controller (control device) having a filter unit with a feedforward control program. Suppress the run-out of the load. The filter unit sequentially calculates the resonance frequency based on the rope length, which is the distance from the rotation center of the rope swing to the center of gravity of the load, and removes components near the calculated resonance frequency from the command signal of the crane. By controlling in this way, the crane inputs the conveyance command from which the component near the resonance frequency is removed to the crane driving device, and controls the crane driving device so that the load does not shake greatly when the load is transferred.

  The technique described in Patent Document 1 uses band removal processing that excludes a specific frequency band from a signal. When the crane uses the band removal process for ground cutting, if the rotational speed of the winch exceeds the predetermined speed when the suspended load leaves the ground, a step-like speed change including the entire frequency band will occur on the telescopic boom and wire rope. Arise. Therefore, a natural frequency is given to the telescopic boom and the wire rope, and the suspended load is pitched. In the band removal process, when the drive signal for driving the winch is constant, a specific frequency band cannot be removed because the drive signal does not include a frequency component. Therefore, when the rotation speed of the winch increases when the suspended load leaves the ground, the crane has less room for further increasing the rotation speed of the winch, and it is difficult to obtain the effect of suppressing the pitching of the suspended load.

International Publication No. 2005/012155

  The objective of this invention aims at provision of the crane which can suppress the pitching of a suspended load after completion of ground cutting.

  The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.

  That is, in the crane that performs ground cutting control for lifting the suspended load from the ground by controlling the rotation speed of the winch to be equal to or lower than the predetermined speed, the band removing unit that removes a signal of a specific frequency band from the winch driving signal for driving the winch. After removing the suspended load from the ground by carrying out ground cutting control, the rotational speed of the winch is controlled by removing the signal in the frequency band that induces the vertical swing of the suspended load from the winch drive signal by the band removing means. It is.

  In the ground cutting control, the crane considers the bending of the telescopic boom when winding the winch, and uses both the swivel turning, the expansion and contraction and undulation of the telescopic boom, and the winch hoisting and lowering operations in combination. Control is performed to lift the suspended load from the ground in a state in which the tip of the telescopic boom is disposed vertically above the hook that is locked to the hook through a required hanging tool.

  The crane removes the frequency band of the natural frequency of at least one of the telescopic boom and the wire rope when removing the frequency band signal that induces the pitching of the suspended load from the winch drive signal by the band removing means. is there.

  The predetermined speed of the crane is a speed that does not cause resonance at least between the telescopic boom and the wire rope.

  The crane includes a winch operation tool that sets a target rotation speed of the winch according to the operation position, and a winch drive signal gradually approximates the rotation speed of the winch to the target rotation speed.

  The present invention has the following effects.

  In the crane, the rotation speed of the winch is controlled without causing the vertical swing of the suspended load. Thereby, the pitching of a suspended load can be suppressed after completion of ground cutting.

  In the crane, after performing the ground cutting control for preventing the swinging of the load at the time of the ground cutting, the rotation speed of the winch is controlled without causing the vertical swing of the suspended load. Thereby, the pitching of a suspended load can be suppressed after completion of ground cutting.

  In the crane, the rotation speed of the winch is controlled without causing at least one pitching of the telescopic boom and the wire rope. Thereby, the pitching of a suspended load can be suppressed after completion of ground cutting.

  In the crane, when lifting a suspended load from the ground, at least the telescopic boom and the wire rope are not pitched. Thereby, the pitching of a suspended load can be suppressed after completion of ground cutting.

  In the crane, when the rotation speed of the winch reaches the target rotation speed, a rapid speed change does not occur between the telescopic boom and the wire rope. Thereby, the pitching of a suspended load can be suppressed after completion of ground cutting.

The side view showing the whole crane composition concerning one embodiment of the present invention. The figure which shows the structure of the control apparatus of the crane which concerns on one Embodiment of this invention. (A) Side view showing a working state at the time of hoisting in the ground cutting control of the crane according to one embodiment of the present invention, (b) In the ground cutting control of the crane according to one embodiment of the present invention, at the time of rising The side view which shows the working state of. (A) The figure which shows the graph showing the change of the rotational speed of a sub winch, and the height of a suspended load at the time of the ground cutting of a conventional crane, and after completion of the ground cutting, (b) It concerns on one Embodiment of this invention. The figure which shows the graph showing the change with the rotational speed of a sub winch, and the height of a suspended load in the ground cutting control and zone | band removal control of a crane. The figure which shows the flowchart showing the control aspect of ground cutting control and zone | band removal control in the crane concerning one Embodiment of this invention.

  Below, the crane 1 which concerns on one Embodiment of a crane is demonstrated using FIG. 1 and FIG. In the present embodiment, a mobile crane will be described as the crane 1. However, any crane 1 may be used as long as the crane 1 includes the telescopic boom 8, the swivel base 7, and the winch that are raised and lowered by the actuator.

  As shown in FIG. 1, the crane 1 is a mobile crane that can move to an unspecified location. The crane 1 has a vehicle 2 and a crane device 6.

  The vehicle 2 conveys the crane device 6. The vehicle 2 has a plurality of wheels 3 and travels using an engine (not shown) as a power source. The vehicle 2 is provided with an outrigger 5. The outrigger 5 includes a projecting beam that can be extended by hydraulic pressure on both sides in the width direction of the vehicle 2 and a hydraulic jack cylinder that can extend in a direction perpendicular to the ground. The vehicle 2 can extend the workable range of the crane 1 by extending the outrigger 5 in the width direction of the vehicle 2 and grounding the jack cylinder.

  The crane apparatus 6 lifts the suspended load W with a wire rope. The crane device 6 includes a swivel base 7, a telescopic boom 8, a jib 9, a main hook block 10, a sub hook block 11, a hoisting cylinder 12, a main winch 13, a main wire rope 14, a sub winch 15, a sub wire rope 16, and a cabin 17 And a control device 18 (see FIG. 2).

  The swivel base 7 is configured to allow the crane device 6 to swivel. The swivel base 7 is provided on the frame of the vehicle 2 via an annular bearing. The annular bearing is arranged so that the center of rotation is perpendicular to the installation surface of the vehicle 2. The swivel base 7 is configured to be rotatable in one direction and the other direction with the center of the annular bearing as the center of rotation.

  The telescopic boom 8 supports the wire rope so that the suspended load W can be lifted. The telescopic boom 8 is configured to be telescopic in the axial direction by being moved by an unillustrated telescopic cylinder. The telescopic boom 8 is provided on the swivel base 7 so that the base end portion thereof can swing. Accordingly, the telescopic boom 8 is configured to be horizontally rotatable and swingable on the frame of the vehicle 2. The telescopic boom 8 is provided with a posture detector 19 (see FIG. 2) that detects the telescopic boom length and the telescopic boom hoisting angle.

  The jib 9 expands the lift and work radius of the crane device 6. The jib 9 is held in a posture along the telescopic boom 8. The jib 9 is configured to be connectable to the distal end portion of the telescopic boom 8.

  The main hook block 10 suspends the suspended load W. The main hook block 10 is provided with a plurality of hook sheaves around which the main wire rope 14 is wound and a main hook that suspends the suspended load W. The sub hook block 11 suspends the suspended load W. The sub hook block 11 is provided with a sub hook for hanging the suspended load W.

  The raising / lowering cylinder 12 raises and lowers the telescopic boom 8 and maintains the posture of the telescopic boom 8. The hoisting cylinder 12 is composed of a hydraulic cylinder composed of a cylinder part and a rod part. In the hoisting cylinder 12, the end of the cylinder portion is slidably connected to the swivel 7, and the end of the rod portion is slidably connected to the telescopic boom 8. The operation of the hoisting cylinder 12 is controlled by the hoisting operation valve 20 (see FIG. 2). The hoisting operation valve 20 is composed of an electromagnetic switching valve that can be switched by moving a spool.

  The main winch 13 which is a hydraulic winch is for carrying in (winding up) and feeding out (winding down) the main wire rope 14. The main winch 13 is configured such that a main drum around which the main wire rope 14 is wound is rotated by a main hydraulic motor. The main winch 13 feeds out the main wire rope 14 wound around the main drum by supplying hydraulic oil so that the main hydraulic motor rotates in one direction, and the main hydraulic motor rotates in the other direction. In this way, the main oil rope 14 is wound around the main drum and fed in by supplying the hydraulic oil.

  A sub-winch 15 that is a hydraulic winch is used for feeding and unloading the sub-wire rope 16. The sub winch 15 is configured such that a sub drum around which the sub wire rope 16 is wound is rotated by a sub hydraulic motor 21 (see FIG. 2). The sub winch 15 feeds the sub wire rope 16 wound around the sub drum by supplying hydraulic oil so that the sub hydraulic motor 21 rotates in one direction, and the sub hydraulic motor 21 rotates in the other direction. In this way, the hydraulic oil is supplied so that the sub wire rope 16 is wound around the sub drum and fed.

  The cabin 17 covers the cockpit. The cabin 17 is provided on the side of the telescopic boom 8 in the swivel base 7. A cockpit is provided inside the cabin 17. In the cockpit, a main winch operation lever for operating the main winch 13, a sub winch operation lever 22 for operating the sub winch 15 (see FIG. 2), a hoisting operation tool for operating the telescopic boom 8, A handle for moving the crane 1, a shift lever, an accelerator pedal, a brake pedal, a ground cutting start switch 23 (see FIG. 2) for performing ground cutting control, and the like are provided.

  The load detector 24 detects the load of the suspended load W. The load detector 24 is provided on the hoisting cylinder 12.

  As shown in FIG. 2, the sub-winch operation lever 22 that is a winch operation tool sets the target rotation speed x that is the target rotation speed of the sub-winch 15 and the sub-winch 15 according to the tilt position of the lever. The rotation speed is increased or decreased. The sub winch operation lever 22 is provided with a sensor for detecting the operation position of the lever.

  The crane 1 configured as described above can move the crane device 6 to an arbitrary position by running the vehicle 2. Moreover, the crane 1 raises the telescopic boom 8 to an arbitrary hoisting angle by the hoisting cylinder 12, extends the telescopic boom 8 to an arbitrary telescopic boom length, or connects the jib 9 to the crane device 6. The head and working radius can be expanded.

  Below, the control means and structure of the control apparatus 18 which the crane 1 comprises are demonstrated using FIG.

  The control device 18 performs a ground cutting control for preventing the swinging of the load at the time of the ground cutting and a band removal control for lifting the suspended load W by preventing the vertical swing of the suspended load W after the ground cutting control. The control device 18 includes a mode discriminating unit 25, a slow start processing unit 26, a band removal processing unit 27, a ground cutting control calculator 28, and a speed signal selecting unit 29. The control device 18 is provided in the vehicle 2. The control device 18 may actually be configured such that a CPU, ROM, RAM, HDD, or the like is connected by a bus, or may be configured by a one-chip LSI or the like.

  The mode discriminating unit 25 discriminates the current mode. There are three modes: normal mode, ground cutting control mode, and band elimination control mode. The mode discriminating means 25 is connected to the ground cutting start switch 23, the load detector 24, the sub winch operation lever 22, the slow activation processor 26, and the speed signal selecting means 29.

  The slow start processing unit 26 performs sub-routing from the rotational speed of the sub-winch 15 corresponding to the speed signal at the time of completion of ground cutting to the rotational speed of the sub-winch 15 corresponding to the speed signal corresponding to the operation position of the sub-winch operation lever 22 A signal for gradually increasing the rotation speed of the winch 15 is calculated. Thereby, the rotation speed of the sub winch 15 gradually approaches the target rotation speed x set by the sub winch operation lever 22. The slow activation processor 26 is connected to the sub-winch operation lever 22, the band removal processor 27, and the ground cutting control calculator 28.

  The band removal processor 27 removes the frequency bands of the natural frequencies of the telescopic boom 8 and the sub wire rope 16 from the speed signal output from the slow activation processor 26. Specifically, a notch filter that greatly attenuates a specific frequency band is used as the band removal process. The band removal processor 27 is connected to the speed signal selection means 29.

  The ground cutting control calculator 28 calculates a signal for controlling the rotation speed of the sub winch 15 and the undulation of the telescopic boom 8 based on the telescopic boom length and the telescopic boom undulation angle detected by the attitude detector 19. is there. The earth cutting control calculator 28 is connected to the load detector 24, the attitude detector 19, and the speed signal selection means 29.

  The speed signal selection means 29 selects a rotational speed signal for driving the sub winch 15 according to the mode. In the normal mode, the rotation speed signal from the sub-winch operation lever 22 is selected. In the ground cutting control mode, the rotation speed signal from the ground cutting control calculator 28 is selected. In the band removal control mode, the band removal processor 27 is selected. Select the rotation speed signal from. The speed signal selection means 29 is connected to the sub hydraulic motor 21 and the hoisting operation valve 20.

  Next, signals of the control device 18 will be described.

  The ground cutting start switch signal sw is a signal output when the ground cutting start switch 23 is turned ON. The ground cutting start switch signal sw is output from the ground cutting start switch 23 to the mode determining means 25.

  The load detection signal Wt is a signal output according to the load detected by the load detector 24. The load detection signal Wt is output from the load detector 24 to the mode determination means 25 and the ground cutting control calculator 28.

  The lever operation signal Xw is a signal output according to the operation position of the sub winch operation lever 22. The lever operation signal Xw is output from the sub-winch operation lever 22 to the mode discriminating means 25, the slow activation processor 26, and the speed signal selecting means 29.

  The boom length detection signal L is a signal output according to the length of the telescopic boom 8 detected by the posture detector 19. The boom length detection signal L is output from the attitude detector 19 to the ground cutting control calculator 28.

  The boom hoisting angle detection signal θ is a signal output according to the hoisting angle of the telescopic boom 8 detected by the attitude detector 19. The boom hoisting angle detection signal θ is output from the attitude detector 19 to the ground cutting control calculator 28.

  The mode signal mode is a signal output according to the mode. The mode signal mode is output from the mode determination unit 25 to the slow activation processor 26 and the speed signal selection unit 29. The mode signal mode outputs 1 as a signal in the normal mode, outputs 2 as a signal in the ground cutting control mode, and outputs 3 as a signal in the band removal control mode.

  The ground cutting control hoisting signal Xw1 is a signal for driving the sub hydraulic motor 21 at the time of ground cutting control. The ground cutting control hoisting signal Xw1 is output from the ground cutting control computing unit 28 to the slow activation processor 26 and the speed signal selecting means 29.

  The ground cutting control undulation signal Xd1 is a signal for controlling the undulation operating valve 20 during the ground cutting control. The ground cutting control undulation signal Xd1 is output from the ground cutting control computing unit 28 to the slow activation processor 26 and the speed signal selection means 29.

  The slow start signal Xw2 is the rotational speed of the sub winch 15 from the rotational speed of the sub winch 15 corresponding to the ground cutting control hoisting signal Xw1 when the ground cutting is completed to the rotational speed of the sub winch 15 corresponding to the lever operation signal Xw. Is a signal that gradually increases. The slow start signal Xw2 is output from the slow start processor 26 to the band removal processor 27.

  The band removal signal Xfw is a signal obtained by removing the frequency bands of the natural frequencies of the telescopic boom 8 and the sub wire rope 16 from the slow activation signal Xw2. The band removal signal Xfw is output from the band removal processor 27 to the speed signal selection means 29.

  The sub winch rotation speed signal Yw is a signal for driving the sub winch 15 at a corresponding rotation speed. The sub winch rotation speed signal Yw is output from the speed signal selection means 29 to the sub hydraulic motor 21.

  The undulation control signal Yd is a signal for controlling the undulation of the telescopic boom 8. The undulation drive signal Yd is output from the speed signal selection means 29 to the undulation operation valve 20.

  Next, control modes of signal output of the ground cutting control and the band removal control of the crane 1 will be described.

  The posture detector 19 outputs the boom length detection signal L and the boom hoisting angle detection signal θ to the ground cutting control calculator 28. The ground cutting control calculator 28 calculates the ground cutting control hoisting signal Xw1 and the ground cutting control undulation signal Xd1 based on the boom length detection signal L and the boom undulation angle detection signal θ, and the speed signal selection means 29. Output to.

  When the ground cutting start switch 23 is turned ON, the ground cutting start switch signal sw is output to the mode determining means 25. At this time, when the sub-winch operation lever 22 is tilted in the direction to wind up the sub-winch 15, the lever operation signal Xw is output to the mode determination means 25. The mode discriminating unit 25 changes the mode signal mode from 1 (normal mode) to 2 (ground cutting control mode), and outputs it to the speed signal selecting unit 29. The speed signal selection means 29 outputs the ground cutting control hoisting signal Xw1 to the sub hydraulic motor 21 as the sub winch rotation speed signal Yw, and outputs the ground cutting control undulation signal Xd1 to the hoisting operation valve 20 as the undulation control signal Yd. To do.

  During the ground cutting control, the load detector 24 outputs a load detection signal Wt to the mode determination unit 25. When the suspended load W is lifted from the ground, the detection value of the load detector 24 becomes constant. Therefore, when the detection value of the load detector 24 is constant after the increase, the mode discriminating means 25 has completed the ground cutting. Is determined. Then, the mode discriminating unit 25 changes the mode signal mode from 2 (ground cutting control mode) to 3 (band removal control mode) after a predetermined time from the determination, and outputs it to the speed signal selecting unit 29.

  When switching from the ground cutting control to the band removal control, the ground cutting control calculator 28 outputs the ground cutting control hoisting signal Xw1 to the slow activation processor 26. The sub winch operation lever 22 outputs a lever operation signal Xw to the slow activation processor 26. The slow start processor 26 calculates the slow start signal Xw2 based on the ground cutting control hoisting signal Xw1 and the lever operation signal Xw, and outputs it to the band elimination processor 27. The band removal processor 27 outputs a band removal signal Xfw obtained by removing the frequency bands of the natural frequencies of the telescopic boom 8 and the subwire rope 16 from the slow activation signal Xw2 to the speed signal selection means. The speed signal selection means 29 outputs the band removal signal Xfw to the sub hydraulic motor 21 as the sub winch rotation speed signal Yw.

  During the band removal control, the slow start processor 26 outputs the slow start signal Xw2 to the mode determination unit 25. When the rotational speed of the sub winch 15 corresponding to the slow activation signal Xw2 and the rotational speed of the sub winch 15 corresponding to the lever operation signal Xw become the same, the mode determination means 25 sets the mode signal mode to 3 (band removal control). Mode) to 1 (normal mode) and output to the speed signal selection means 29.

  Next, the ground cutting control of the crane 1 will be described with reference to FIG.

  As shown in FIG. 3A, since the control device 18 winds up the sub winch 15 for a unit time, the force that winds up the sub winch 15 acts on the telescopic boom 8 to cause bending, so that the tip of the telescopic boom 8 The part moves from point A to point B.

  As shown in FIG. 3 (b), the control device 18 raises only the telescopic boom 8 by the unit hoisting amount, so that the tip of the telescopic boom 8 moves from point B to point C. The horizontal movement amount of the distal end portion of the telescopic boom 8 to B is cancelled, and the distal end portion of the telescopic boom 8 moves again vertically above the suspended load W.

  Whether or not the ground cutting of the suspended load W is completed is determined based on whether or not the detection value detected by the load detector 24 is constant, and the control device 18 detects that the load detector 24 detects. Until the value becomes constant, the winding of the sub winch 15 (from the point A to the point B) and the raising (the point B to the point C) are repeated.

  As a result, since the tip of the telescopic boom 8 is positioned vertically above the suspended load W at the time of the ground cutting, the suspended load W is caused to move immediately below the tip of the telescopic boom 8 simultaneously with the ground cutting. No run-out occurs. In addition, although the case where the vertical bending occurred was described, the present invention is not limited to this. When the lateral bending occurs, the telescopic boom 8 is turned so that the tip of the telescopic boom 8 is directly above the suspended load W. It can also be moved. Alternatively, the tip of the telescopic boom 8 may be moved directly above the suspended load W by lowering the sub winch 15 and expanding / contracting the telescopic boom 8. In other words, in the ground cutting control, the crane 1 uses the swiveling base 7 to rotate, the telescopic boom 8 to extend and undulate, and the sub-winch 15 to wind up and down in combination. The suspended load W is lifted from the ground in a state where the distal end portion of the telescopic boom 8 is disposed vertically above the hook locked through the tool.

  Next, with reference to FIG. 4, a comparison is made between the case where both the ground cutting control and the band removal control of the crane 1 are not performed and the case where both the ground cutting control and the band removal control are performed. explain. The target rotation speed x is set according to the operation position of the sub winch operation lever 22. The predetermined speed at the time of ground cutting control is a step-like speed change between the telescopic boom 8 and the sub-wire rope 16 when the ground cutting is completed and the suspended load W is not restrained by the ground. There is no speed.

  As shown in FIG. 4 (a), when both the ground cutting control and the band removal control are not performed, the operator increases the sub winch 15 to the target rotational speed x during the ground cutting operation (see the solid line V). The ground cutting is completed at time t1, and the suspended load W is not restrained by the ground. At this time, since the sub winch 15 is rolled up, the telescopic boom 8 and the sub wire rope 16 cause a step-like speed change including their natural frequencies, so that the suspended load W is pitched (see the solid line H). And the suspended load W is lifted in the state where the vertical swing of the suspended load W is continued.

  As shown in FIG. 4B, when both the ground cutting control and the band removal control are performed, the control device 18 controls the rotation speed of the sub winch 15 to be equal to or lower than a predetermined speed during the ground cutting control (see the solid line V). At time t2, the ground cutting is completed, and the suspended load W is not restrained by the ground. At this time, since the step-like speed change does not occur between the telescopic boom 8 and the sub-wire rope 16, resonance between the telescopic boom 8 and the sub-wire rope 16 does not occur, and the suspended load W does not cause pitching (solid line). H). Then, the control device 18 removes the band removal signal Xfw from the slow start signal Xw2 (see the two-dot chain line Va for the speed corresponding to the signal), excluding the frequency bands of the natural frequencies of the telescopic boom 8 and the sub wire rope 16. To drive the sub winch 15. At this time, since the sub winch 15 does not give vibrations of the natural frequencies to the telescopic boom 8 and the sub wire rope 16, the suspended load W is lifted without causing the suspended load W to sway. At time t3, the speed corresponding to the slow activation signal Xw2 (see FIG. 2) reaches the target rotational speed x, and the band removal control ends.

  With this configuration, the crane 1 gradually increases the rotational speed of the sub winch 15 to the target rotational speed x without causing the vertical swing of the suspended load W after performing the ground cutting control. Thereby, the pitching of the suspended load W can be suppressed after completion of ground cutting.

  Next, the control mode of the ground cutting control and the band removal control of the crane 1 will be specifically described with reference to FIG. In the present embodiment, it is assumed that the ground cutting control switch 23 is ON.

In step S100, the control device 18 determines whether or not the sub winch operation lever 22 is tilted in the winding direction.
As a result, when it is determined that the sub winch operation lever 22 is tilted in the winding direction, the control device 18 shifts the step to step S110.
On the other hand, if it is determined that the sub-winch operation lever 22 is not tilted in the winding direction, the control device 18 shifts the step to step S100.

  In step S110, the control device 18 changes the mode signal mode from 1 (normal mode) to 2 (ground cutting control mode), and shifts the step to step S120.

  In step S120, the control device 18 executes ground cutting control, and the step proceeds to step S130.

In step S130, the control device 18 determines whether or not the detected value detected by the load detector 24 is constant after the increase, that is, whether or not the ground cutting is completed.
As a result, when it is determined that the detected value detected by the load detector 24 is constant after the increase, that is, the ground cutting is completed, the control device 18 shifts the step to step S140.
On the other hand, when it is determined that the detection value detected by the load detector 24 is not constant after the increase, that is, the ground cutting is not completed, the control device 18 shifts the step to step S130.

In step S140, the control device 18 determines whether or not a predetermined time has elapsed since the earth cutting was completed.
As a result, when it is determined that the predetermined time has elapsed since the earth cutting is completed, the control device 18 shifts the step to step S200.
On the other hand, when it is determined that the predetermined time has not elapsed since the completion of ground cutting, the control device 18 shifts the step to step S140.

  In step S200, the control device 18 stores the ground cutting control hoisting signal Xw1, and shifts the step to step S210.

  In step S210, the control device 18 changes the mode signal mode from 2 (ground cutting control mode) to 1 (band removal control mode), and the process proceeds to step S220.

  In step S <b> 220, the control device 18 acquires the lever operation signal Xw from the sub winch operation lever 22, and shifts the step to step 230.

  In step S230, the control device 18 calculates the slow activation signal Xw2 based on the ground cutting control hoisting signal Xw1 in step S200 and the lever operation signal Xw in step S220, and shifts the step to step S240.

In step S240, the control device 18 determines whether or not the rotational speed of the sub winch 15 corresponding to the slow activation signal Xw2 has reached the target rotational speed x.
As a result, when it is determined that the rotation speed of the sub winch 15 corresponding to the slow activation signal Xw2 has reached the target rotation speed x, the control apparatus 18 shifts the step to step S250.
On the other hand, when it is determined that the rotation speed of the sub winch 15 corresponding to the slow activation signal Xw2 has not reached the target rotation speed x, the control apparatus 18 shifts the step to step S260.

  In step S250, the control device 18 changes the mode signal mode from 3 (ground cutting control mode) to 1 (normal mode), and ends the process.

  In step S260, the control device 18 outputs to the sub hydraulic motor 21 a band removal signal Xfw obtained by removing the frequency bands of the natural frequencies of the telescopic boom 8 and the sub wire rope 16 from the slow start signal Xw2 in step S230. The step moves to step S230.

  In the above-described ground cutting control and band removal control, the suspended load W is grounded and wound up using the sub winch 15, but the suspended load W may be transported using the main winch 13. . Further, the frequency band for performing the band removal process is not limited to the natural frequencies of the telescopic boom 8 and the sub wire rope 16, and may be any frequency band that induces the pitching of the suspended load W. Furthermore, the frequency band for performing the band removal process may be one of the natural frequencies of the telescopic boom 8 and the sub wire rope 16. And the rotation speed of the sub winch 15 at the time of ground cutting control should just be a speed which does not produce a resonance in the telescopic boom 8 and the sub wire rope 16 at least.

  The above-described embodiments are merely representative, and various modifications can be made without departing from the scope of one embodiment. It goes without saying that the present invention can be embodied in various forms, and the scope of the present invention is indicated by the description of the scope of claims, and the equivalent meanings of the scope of claims, and all the scopes within the scope of the claims. Includes changes.

1 Crane 15 Sub winch 19 Control device 27 Band removal processor W Suspended load

Claims (5)

In a crane that performs ground cutting control to lift the suspended load from the ground by controlling the rotation speed of the winch below a predetermined speed,
Band removing means for removing a signal of a specific frequency band from a winch drive signal for driving the winch,
After carrying out the ground cutting control and lifting the suspended load from the ground,
A crane that controls the rotation speed of the winch by removing a signal in a frequency band that induces pitching of the suspended load from the winch drive signal by the band removing means. In the ground cutting control, considering the bending of the telescopic boom when the winch is wound up,
In combination with the turning of the swivel, the expansion and contraction and undulation of the telescopic boom, and the operations of hoisting and lowering the winch,
2. The crane according to claim 1, wherein the crane is controlled to lift the suspended load from the ground in a state where the distal end portion of the telescopic boom is disposed vertically above a hook that is locked to the suspended load via a required lifting tool.   When the signal of the frequency band that induces the pitching of the suspended load is removed from the winch drive signal by the band removing means, the frequency band of the natural frequency of at least one of the telescopic boom and the wire rope is removed. The crane according to claim 1 or 2.   The crane according to any one of claims 1 to 3, wherein the predetermined speed is a speed that does not cause resonance between at least the telescopic boom and the wire rope. A winch operation tool for setting a target rotational speed of the winch according to an operation position,
The crane according to any one of claims 1 to 4, wherein the winch drive signal causes the rotational speed of the winch to gradually approach the target rotational speed.

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