JP2020159106A - Pile extraction device - Google Patents

Abstract

To provide a pile extraction device that can prevent damage to a main body due to vibration when extracting a pile.SOLUTION: A pile extraction device 1 comprises: a vibro-device 40 that has a holding part 41 for holding a pile and an excitor for vibrating the holding part 41; a main body that includes a traction mechanism for pulling a rope for suspending the vibro-device 40; a vibration load identification unit that identifies a vibration load applied to the main body; and a determination unit that determines whether or not a load based on the vibration load identified by the vibration load identification unit exceeds a permissible range.SELECTED DRAWING: Figure 1

Description

The present invention relates to a pile pulling device for pulling piles.

Patent Document 1 discloses a vibrating pile punching machine that drives a pile into the soil or pulls out the pile from the soil by a pile gripping device and a vibrator suspended from a hook of a crane. More specifically, the pile can be driven into the soil or pulled out from the soil by vibrating the exciter while the pile gripping device grips the pile.

JP-A-2018-105120

When a pile is pulled out using a vibrating pile punching machine, it is common to vibrate in a loosened state in order to prevent vibration from propagating from the exciter to the crane. However, when the pile is firmly buried in the soil, or when the operator tries to shorten the work, the vibrator may be operated with tension applied to the rope.

In such a case, a load is applied to the crane due to the vibration propagating from the oscillator through the rope. Therefore, even though the load due to the weight of the object suspended from the boom is low, the load due to vibration may damage the crane.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a pile pulling device capable of preventing damage to the main body due to vibration during pile pulling.

In order to solve the above-mentioned problems, one aspect of the present invention is a vibro device having a holding portion for holding a pile, a vibrating portion for vibrating the holding portion, and a traction mechanism for pulling a rope suspending the vibro device. A main body including the above, a vibration load specifying unit that specifies the vibration load applied to the main body, and a determination unit that determines whether or not the load based on the vibration load specified by the vibration load specifying unit exceeds an allowable range. It is characterized by being prepared.

According to the present invention, it is possible to prevent damage to the main body due to vibration during pile removal. Issues, configurations and effects other than the above will be clarified in the following description of the embodiment.

It is a side view of the pile pulling device which concerns on this embodiment. It is a functional block diagram of a pile pulling device. This is an example of a distortion waveform based on the load cell detection result. It is a flowchart of operation control processing. It is a conceptual diagram which shows the calculation method of the total load which concerns on a modification.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a side view of the pile pulling device 1 according to the present embodiment. Unless otherwise specified, the front, back, left, and right sides in the description of FIG. 1 are based on the viewpoint of the operator who operates by boarding the pile pulling device 1.

As shown in FIG. 1, the pile pulling device 1 includes a crawler crane (main body) 100 and a vibro device 40. In this embodiment, an example in which a vibro device 40 is suspended from a general-purpose crawler crane 100 to form a pile pulling device 1 will be described. However, if the pile 2 can be pulled out, the specific configuration of the pile pulling device 1 is not limited to the example of FIG. As another example, instead of the crawler crane 100, the vibro device 40 may be suspended from the main body designed for the pile pulling device 1.

The crawler crane 100 is composed of a lower traveling body (crawler) 10 that can travel and an upper rotating body (support) 20 that is rotatably supported by the lower traveling body 10 via a swivel wheel 21. However, the main body may not include one or both of the lower traveling body 10 and the upper rotating body 20. That is, the main body does not have to run or turn.

The lower traveling body 10 is provided with a pair of endless tracks at both ends in the left-right direction. The lower traveling body 10 is transmitted forward and backward by the rotation of the hydraulic motor (not shown). The hydraulic motor is rotated by supplying hydraulic oil from a hydraulic pump (not shown) driven by an engine (not shown). As a result, the crawler crane 100 travels. The lower traveling body 10 may be wheeled instead of the endless track.

The upper swivel body 20 swivels around the swivel wheel 21 by rotating a swivel motor (not shown). The upper swing body 20 mainly includes a boom 22, a cabin 23, an undulating winch 24, an elevating winch (traction mechanism) 25, a backstop 26, a counterweight 27, and a gantry 30.

The base end portion of the boom 22 is supported by the upper swing body 20 so as to be undulating in the vertical direction at the front end of the upper swing body 20 and at the central portion in the left-right direction. Further, the boom 22 extends forward and upward of the upper swing body 20. A hook rope (rope) 25a extending from the elevating winch 25 hangs down from the tip of the boom 22, and the hook 22a is attached to the tip of the hook rope 25a.

The cabin 23 is formed with an internal space on which an operator who operates the crawler crane 100 is boarded. An operation of running the lower traveling body 10 in the internal space of the cabin 23, turning the upper turning body 20, raising and lowering the boom 22, raising and lowering the hook 22a, and accepting an operator's operation for driving the vibro device 40. A part (not shown) is arranged. The pile pulling device 1 operates when the operator boarding the cabin 23 operates the operation unit.

The operation unit includes, for example, an accelerator pedal for controlling the engine speed, a traveling lever for steering and braking the lower traveling body 10, a turning lever for turning the upper turning body 20, an undulating lever for rotating the undulating winch 24, and an elevating winch 25. It is provided with an elevating lever for rotating the lever, a vibration switch for vibrating and stopping the vibration unit 42 described later, and the like. However, the specific configuration of the operation unit is not limited to the above-mentioned example as long as the operation of the operator can be accepted.

The undulating winch 24 raises and lowers the boom 22 by feeding out or winding up the undulating rope 24a. The elevating winch 25 raises and lowers the hook 22a by feeding out or winding the hook rope 25a. The swivel motor, the undulating winch 24, and the elevating winch 25 (these may be collectively referred to as an "actuator") rotate by receiving hydraulic oil supply from, for example, a hydraulic pump (not shown). It is a hydraulic type.

However, the towing mechanism is not limited to the elevating winch 25 as long as it has at least a function of pulling the rope on which the vibro device 40 is suspended. As another example of the traction mechanism, it may be a hydraulic cylinder.

The backstop 26 presses the boom 22 in a direction to lie down in order to prevent the boom 22 from falling backward. One end of the backstop 26 is rotatably supported by the upper swing body 20, and the other end is rotatably supported near the center of the boom 22. The backstop 26 is provided with a cushioning spring 26a that contracts when the undulation angle of the boom 22 exceeds the threshold angle.

Then, the backstop 26 presses the boom 22 in a direction to lie down by the restoring force of the contracted cushioning spring 26a. If the boom 22 can be pressed in a direction in which it falls down, the specific example of the pressing member is not limited to the cushioning spring 26a. As another example, the pressing member may be a hydraulic cylinder or the like to which hydraulic oil having a pressure corresponding to the undulation angle of the boom 22 is supplied. Further, the other end of the backstop 26 may always be in contact with the boom 22, or may be separated from the boom 22 while the undulation angle of the boom 22 is less than the threshold angle.

The counterweight 27 is supported by the upper swivel body 20 on the side opposite to the boom 22 with the swivel wheel 21 interposed therebetween. That is, the counterweight 27 is placed at the rear end of the upper swing body 20. The counterweight 27 is a weight placed on the upper swing body 20 in order to balance with the suspended load suspended on the hook 22a.

The gantry 30 mainly includes a front leg 31 and a rear leg 32. The base end portion of the front leg 31 is rotatably connected to a bracket provided in the central portion of the upper swing body 20. The base end portion of the rear leg 32 is rotatably connected to a bracket provided on the rear side of the upper swing body 20. The gantry 30 stands up and falls down due to expansion and contraction of a hydraulic cylinder (not shown).

A lower spreader 33 having a lower sheave 34 is fixed to the upper end side of the front leg 31. Further, an upper spreader 35 provided with an upper sheave 36 is interposed between the lower spreader 33 and the tip of the boom 22. The undulating rope 24a is hung around the upper sheave 36 of the upper spreader 35 and the lower sheave 34 of the lower spreader 33 a plurality of times.

The upper spreader 35 is connected to a pendant rope 37 fixed to the tip of the boom 22. When the undulating rope 24a is wound or unwound by the undulating winch 24, the boom 22 is undulated by changing the distance between the lower spreader 33 and the upper spreader 35.

If the boom 22 can be raised and lowered with respect to the upper swing body 20, the specific configuration for raising and lowering the boom 22 is not limited to the above-mentioned example. As another example, the crawler crane 100 may include a live mast (not shown) in place of or together with the gantry 30. The live mast is a long rod-shaped member that is rotatably supported by the upper swing body 20 in the vicinity of the connection portion of the boom 22 to the upper swing body 20.

The undulating rope 24a extending from the undulating winch 24 is connected to the upper swivel body 20 via a sheave provided at the tip of the live mast. Further, the tip of the live mast and the tip of the boom 22 are connected by a pendant rope 37. In the above configuration, when the undulating rope 24a is wound by the undulating winch 24, the live mast lays down and the boom 22 rises. On the other hand, when the undulating rope 24a is extended by the undulating winch 24, the live mast is raised and the boom 22 is laid down.

The vibro device 40 is used, for example, in a state of being suspended from a wire locked to a hook 22a. That is, the vibro device 40 is indirectly suspended from the hook rope 25a. The vibro device 40 mainly includes, for example, a holding portion 41 for holding the pile 2 and a vibrating portion 42 for vibrating the holding portion 41.

The holding portion 41 holds the base end portion of the pile 2 whose tip is facing downward. As long as the pile 2 can be held, the specific configuration of the holding portion 41 is not particularly limited, but for example, the pile 2 may be gripped by a plurality of claws, or the pile 2 may be attracted by an electromagnet.

The vibration generating unit 42 is a device that generates vibration. The vibrating unit 42 includes, for example, a motor and an eccentric pendulum. Then, the eccentric pendulum is rotated by the motor to generate vibration. The exciting portion 42 may be a hydraulic type in which the motor is driven by hydraulic pressure, or an electric type in which the motor is driven by electric power.

If the pile 2 can be driven in and out, the specific configuration of the vibro device 40 is not limited to the above-mentioned example, and another well-known vibro device 40 can be used. For example, the vibro device 40 may further include a shock absorber (shock absorber) that suppresses the propagation of vibration to the crawler crane 100. Further, the holding unit 41 and the vibrating unit 42 may be separated from each other as long as the vibration generated by the vibrating unit 42 propagates to the holding unit 41.

When the tip of the pile 2 held by the holding portion 41 is brought into contact with the ground G to drive the vibrating portion 42, the vibrating vibro device 40 plays the role of a hammer and the pile 2 is driven into the soil. (Hereinafter referred to as "pile work"). Since the weight of the vibro device 40 is used in the driving operation, the hook rope 25a is extended to the elevating winch 25 to keep the hook rope 25a loose.

On the other hand, when the pile 2 buried in the soil is held by the holding portion 41 and the vibration generating portion 42 is driven, the soil around the pile 2 is pushed away and a gap is formed around the pile 2. Then, when the hook rope 25a is wound up by the elevating winch 25, the pile 2 is removed from the ground G (hereinafter, referred to as "removal work").

It is desirable to loosen the hook rope 25a when driving the exciting portion 42 even in the removal work. However, when the pile 2 is firmly buried in the soil, the hook rope 25a may be wound up and the pile 2 may be pulled up to vibrate the vibrating portion 42. Further, the operator who wants to improve the work efficiency may drive the exciting portion 42 and wind the hook rope 25a in parallel.

Then, when the vibrating portion 42 is vibrated while the hook rope 25a is tensioned, the vibration generated by the vibrating portion 42 passes through the hook rope 25a to the crawler crane 100 (more specifically, the boom 22 and the upper swing body 20). ) Propagate.

FIG. 2 is a functional block diagram of the pile pulling device 1. As shown in FIG. 2, the pile pulling device 1 mainly includes a load cell (distortion sensor) 51, an acceleration sensor 52, a display 53, and a controller 60.

The load cell 51 detects the distortion generated in the boom 22. The load cell 51 repeatedly outputs a distortion signal (for example, a voltage value) according to the magnitude of distortion at the mounting position to the controller 60 at predetermined time intervals. If the strain generated in the boom 22 can be detected, the specific configuration of the load cell 51 is not particularly limited, and for example, a strain gauge type, a magnetostrictive type, a gyro type, a capacitance type, or the like can be adopted.

As an example, the load cell 51 may be directly attached to the boom 22 to directly detect the distortion generated in the boom 22. As another example, the load cell 51 is attached to the components that raise and lower the boom 22 (undulating winch 24, undulating rope 24a, front leg 31, rear leg 32, lower spreader 33, upper spreader 35, pendant rope 37), and the boom 22 is attached. The distortion that occurs in the above may be detected indirectly.

If the strain generated in the boom 22 can be detected, the specific mounting position of the load cell 51 is not particularly limited, but in order to reduce the influence of the vibration propagating from the vibration generating portion 42 to the crawler crane 100, the tip of the boom 22 It is desirable to place it on the downstream side of the vibration propagation direction.

As an example, when the load cell 51 is attached to the boom 22, the base end side of the boom 22 is desirable from the support position of the backstop 26. As another example, when the load cell 51 is attached to the component that raises and lowers the boom 22, it is desirable that the load cell 51 is located downstream of the upper spreader 35. As shown in FIG. 1, the load cell 51 according to the present embodiment is attached to the undulating winch 24 supported by the upper swing body 20.

The acceleration sensor 52 detects the vibration acceleration (speed change per unit time) of the boom 22, and repeatedly outputs an acceleration signal indicating the detection result to the controller 60 at predetermined time intervals. The vibration acceleration refers to, for example, the acceleration generated on the boom 22 by the vibration of the exciting portion 42 and the acceleration generated on the boom 22 by receiving an external force such as wind, and does not include the acceleration when raising and lowering the boom 22. As the acceleration sensor 52, for example, a well-known gyro sensor can be adopted.

Vibration acceleration is generated in the boom 22 by propagating the vibration from the vibrating portion 42 to the boom 22. Therefore, it is desirable to attach the acceleration sensor 52 to a position close to the tip of the boom 22 in order to detect the vibration acceleration before the vibration propagated from the vibration portion 42 is greatly attenuated.

More specifically, it is desirable that the acceleration sensor 52 is attached to the tip end side of the boom 22 from the support position of the backstop 26. As shown in FIG. 1, the acceleration sensor 52 according to the present embodiment is attached to a sheave that guides the hook rope 25a at the tip of the boom 22.

However, the specific example of the acceleration sensor 52 is not limited to the gyro sensor, and it is sufficient if the vibration acceleration of the boom 22 can be detected. As another example of the acceleration sensor 52, a semiconductor type acceleration sensor or a piezoelectric type acceleration sensor may be used. Further, the mounting position of the acceleration sensor 52 is not limited to the above-mentioned example as long as the vibration acceleration of the boom 22 can be detected. As another example, the acceleration sensor 52 may be attached to the upper swing body 20.

The display 53 is a notification device that is arranged in the cabin 23 and notifies the operator boarding the cabin 23 of information. However, the specific example of the notification device is not limited to the display 53 as long as the information can be notified to the operator using characters, images, sounds, lights, and the like. As another example, the notification device may be a speaker that outputs a warning sound or a guide sound, an LED lamp that lights up or blinks, and the like.

The controller 60 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), an HDD (Hard Disk Drive), and the like. Then, when the CPU reads the program from the ROM, RAM, and HDD and executes it, the processing described later is realized.

However, the specific configuration of the controller 60 is not limited to the above-mentioned example as long as the processing described later can be realized. As another example, the controller 60 may be realized by hardware such as an ASIC (Application Specific Integrated Circuit) and an FPGA (Field-Programmable Gate Array).

The controller 60 controls at least one of the vibration unit 42 and the display 53 based on the distortion signal output from the load cell 51 and the acceleration signal output from the acceleration sensor 52. The controller 60 includes, for example, a weight load specifying unit 61, a vibration load specifying unit 62, a determination unit 63, and a notification processing unit 64.

The weight load specifying unit 61 identifies the weight load applied to the crawler crane 100 due to the weight applied to the boom 22 based on the distortion signal output from the load cell 51. Then, the weight load specifying unit 61 repeatedly identifies the weight load at predetermined time intervals, and notifies the determination unit 63 of the specified weight load.

The weight load according to the present embodiment refers to the load [N] applied to the boom 22. More specifically, the weight load according to the present embodiment refers to the load applied to the boom 22 from the hook 22a, the vibro device 40, and the pile 2 when the hook rope 25a is tensioned.

FIG. 3 is an example of a distortion waveform based on the detection result of the load cell 51. When the distortion signal acquired from the load cell 51 is plotted with the horizontal axis representing time and the vertical axis representing the magnitude of the distortion signal, the distortion waveform shown by the fine solid line in FIG. 3 is obtained. Then, the relationship between the load applied to the boom 22 and the magnitude of strain can be specified in advance from the structure, material, etc. of the installation position of the load cell 51. Therefore, the load applied to the boom 22 can be specified by multiplying the distortion signal by a predetermined coefficient.

However, the strain waveform shown in FIG. 3 is superposed with a high frequency component caused by the vibration propagated from the vibration generating portion 42. Therefore, the weight load specifying unit 61 specifies a load (weight load) excluding the influence of vibration as shown by a thick broken line in FIG. 3 by applying a low-pass filter to the strain waveform shown by the fine solid line in FIG. To do.

More specifically, each time the weight load specifying unit 61 acquires a distortion signal from the load cell 51, the acquired distortion signal and the acquisition time are associated with each other and stored in the RAM. Next, the weight load specifying unit 61 may read N distortion signals retroactive from the target time from the RAM, and specify the average value (moving average) of the read distortion signals as the weight load at the target time. ..

Further, the weight load specifying unit 61 may display the specified weight load (that is, the load applied to the boom 22) on the display 53. By using the load after applying the low-pass filter, it is possible to prevent the numerical value displayed on the display 53 from changing rapidly. As a result, the operator who operates the pile pulling device 1 can recognize the transition of the load excluding the influence of vibration.

However, the processing of the weight load specifying unit 61 is not limited to the above example as long as the weight load acting on the boom 22 can be specified. As another example, the weight load specifying unit 61 may frequency-analyze the distortion signal output from the load cell 51 to extract a low-frequency signal, and specify the weight load based on the extracted low-frequency signal.

The vibration load specifying unit 62 specifies the vibration load applied to the crawler crane 100 due to the vibration propagating from the vibration unit 42 to the crawler crane 100 through the hook rope 25a. Then, the vibration load specifying unit 62 repeatedly identifies the vibration load at predetermined time intervals, and notifies the determination unit 63 of the specified vibration load.

The vibration load according to the present embodiment refers to a value obtained by converting the vibration propagated to the boom 22 into a load [N]. That is, the vibration load specifying unit 62 may be specified as the vibration load at the target time by multiplying the vibration acceleration at the target time by the coefficient α. The coefficient α is a conversion coefficient that converts the vibration acceleration into a load, is calculated in advance by an experiment or a simulation based on the material and structure of the boom 22, and is stored in the ROM.

The determination unit 63 adds the weight load specified by the weight load specifying unit 61 and the vibration load specified by the vibration load specifying unit 62 to calculate the total load. More specifically, the determination unit 63 adds the weight load and the vibration load at the same time to calculate the total load. Then, the determination unit 63 determines whether or not the calculated total load exceeds the allowable range, and notifies the notification processing unit 64 of the determination result.

The permissible range according to the present embodiment is the rated load [N] determined according to the working radius of the crawler crane 100. The determination unit 63 calculates the working radius based on the undulation angle of the boom 22 acquired from the undulation angle sensor (not shown) and the preset length of the boom 22, and is currently using the rated load table stored in the ROM. The rated load corresponding to the working radius of is specified. As described above, the allowable range may be a variable value that changes depending on the state of the pile pulling device 1. However, the permissible range is not limited to the variable value, and may be a predetermined fixed value.

When the determination unit 63 determines that the total load exceeds the allowable range, the notification processing unit 64 notifies the operator. The specific method of notification is not particularly limited as long as the operator can understand the state of the pile pulling device 1 or the next thing to be done.

It is an example of the above-mentioned notification that the display 53 displays a screen prompting to stop the vibration unit 42 by operating the vibration switch. Further, displaying a screen on the display 53 prompting the operation of the elevating winch 25 in the direction in which the hook rope 25a is extended is another example of the above-mentioned notification. Further, forcibly stopping the motor of the vibration unit 42 is another example of the above-mentioned notification.

Next, the operation control process executed by the controller 60 will be described with reference to FIG. FIG. 4 is a flowchart of the operation control process. As an example, the controller 60 may start the operation control process at the timing when the vibration unit 42 starts the operation. As another example, the controller 60 starts the operation control process at the timing when the vibrating unit 42 starts the operation and the tension of the undulating rope 24a detected by the tension sensor (not shown) becomes equal to or higher than the threshold value. Just do it.

First, the weight load specifying unit 61 acquires the distortion signal output by the load cell 51, and stores the acquired distortion signal in the RAM in association with the acquisition time (S11). Since the weight load specifying unit 61 stores the distortion signals in the RAM before the start of the operation control process, it is assumed that N or more distortion signals are already stored in the RAM.

Further, the vibration load specifying unit 62 acquires an acceleration signal output by the acceleration sensor 52 (S12). The processes of steps S11 and S12 are executed at the same time or with an extremely short time difference. Hereinafter, the execution time of steps S11 and S12 will be referred to as "target time".

Next, the weight load specifying unit 61 applies a low-pass filter to the distortion waveform stored in the RAM to specify the weight load at the target time (S13). More specifically, the weight load specifying unit 61 transmits N distortion signals (distortion signal of the target time and (N-1) distortion signals immediately before the target time) retroactively from the target time from the RAM. read out. Then, the weight load specifying unit 61 specifies the average value of the read distortion signals as the weight load, and notifies the determination unit 63 of the specified weight load.

Next, the vibration load specifying unit 62 specifies the vibration load at the target time by multiplying the vibration acceleration indicated by the acceleration signal acquired in step S12 by the coefficient α stored in the ROM (S14). Then, the vibration load specifying unit 62 notifies the determination unit 63 of the specified vibration load.

Next, the determination unit 63 adds the weight load acquired from the weight load specifying unit 61 and the vibration load acquired from the vibration load specifying unit 62 to calculate the total load at the target time. Further, the determination unit 63 specifies the rated load (allowable range) corresponding to the working radius of the crawler crane 100 at the target time. Then, the determination unit 63 determines whether or not the total load exceeds the allowable range (S15). Then, the determination unit 63 notifies the notification processing unit 64 of the determination result.

When the determination unit 63 determines that the total load does not exceed the permissible range (S15: No), the controller 60 does not execute the process of step S16, but re-executes the processes after step S11. Hereinafter, the controller 60 repeatedly executes the processes of steps S11 to S15 at predetermined time intervals until the total load exceeds the permissible range or the operation of the exciting unit 42 is stopped.

Then, when the determination unit 63 determines that the total load exceeds the permissible range (S15: Yes), the notification processing unit 64 executes notification to the operator (S16). As an example, the notification processing unit 64 displays a message or an image on the display 53. As another example, the notification processing unit 64 forcibly stops the motor of the vibration unit 42.

According to the above embodiment, for example, the following actions and effects are exhibited.

According to the above embodiment, the weight load caused by the weight applied to the boom 22 is added to the vibration load caused by the vibration propagated from the vibrating portion 42, and the comparison with the allowable range is performed. Therefore, it is possible to prevent the crane from being damaged by the load caused by vibration even though the load caused by the weight of the object suspended from the boom 22 is low.

Further, as in the above embodiment, by arranging the load cell 51 on the downstream side in the vibration propagation direction from the tip of the boom 22, the vibration component superimposed on the distortion signal can be reduced. Further, by arranging the acceleration sensor 52 on the tip side of the boom 22 from the connection position of the backstop 26 as in the above embodiment, the vibration propagated to the boom 22 can be detected before being attenuated.

Here, as described with reference to FIG. 3, the time change (thick broken line) of the weight load is smaller than the vibration load (thin solid line). Therefore, considering a short period of time, it can be considered that the weight load is a constant value and only the vibration load fluctuates. That is, it can be said that the determination unit 63 determines in step S15 whether or not the vibration load substantially exceeds the permissible range (= rated load-weight load).

In the above embodiment, an example of specifying the vibration load by converting the vibration acceleration of the boom 22 into a load has been described. However, if the vibration load acting on the boom 22 can be specified, the unit of the vibration load is the load [N]. Not limited to. As another example, the vibration load specifying unit 62 may specify the vibration acceleration itself of the boom 22 as a vibration load [m / sec]. As yet another example, the vibration load specifying unit 62 may specify the number of times (= frequency) that the direction of the vibration acceleration changes per unit time as the vibration load [Hz].

If the boom 22 continues to vibrate for a long period of time, fatigue accumulates in the boom 22. Therefore, the determination unit 63 may determine whether or not the state in which the frequency indicated by the vibration load is equal to or higher than the threshold frequency continues for the threshold time or longer. The permissible range in this case is a combination of the threshold frequency and the threshold time. Further, in this case, the load cell 51 and the weight load specifying unit 61 can be omitted.

Further, in the above embodiment, an example in which the weight load is specified based on the distortion signal output from the load cell 51 and the vibration load is specified based on the acceleration signal output from the acceleration sensor 52 has been described. However, the combination of sensors is not limited to the above example as long as the weight load and the vibration load can be specified.

As an example, the weight load specifying unit 61 may specify the weight load based on the tension signal output from the tension sensor that detects the tension applied to the undulating rope 24a. As another example, the vibration load specifying unit 62 may specify the vibration load based on the distortion signal output from the load cell attached to the position of the acceleration sensor 52.

As yet another example, the controller 60 may identify the weight load and the vibration load based on the distortion signal output from one load cell 51. FIG. 5 is a conceptual diagram showing a method of calculating the total load according to the modified example.

The weight load specifying unit 61 according to the modified example applies a low-pass filter to the distortion signal output from the load cell 51 to specify the weight load, as in the above embodiment. On the other hand, the vibration load specifying unit 62 according to the modified example identifies the vibration load based on the distortion signal (distortion signal before the low-pass filter is applied) output from the load cell 51. That is, in this modification, the acceleration sensor 52 can be omitted.

As an example, the vibration load specifying unit 62 may specify the vibration load based on the frequency (frequency per unit time) of the strain waveform shown by the fine solid line in FIG. As another example, the vibration load specifying unit 62 may specify the vibration load based on the amplitude of the strain waveform shown by the fine solid line in FIG.

Further, the determination unit 63 compares with the allowable range is not limited to the total load. More specifically, the determination unit 63 may compare the load based on the vibration load with the allowable range, or may compare the load based on the weight load and the vibration load with the allowable range. For example, the determination unit 63 may correct the vibration load using the weight load and compare the corrected vibration load with the allowable range.

The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention, and all of the technical matters included in the technical idea described in the claims of the present invention are the present invention. Is the target of. Although the above-described embodiment shows a suitable example, those skilled in the art can realize various alternative examples, modified examples, modified examples or improved examples from the contents disclosed in the present specification. These are included in the technical scope described in the appended claims.

1 Pile pulling device 2 Pile 10 Lower traveling body 20 Upper swivel body (support)
21 Swivel wheel 22 Boom 22a Hook 23 Cabin 24 Undulating winch 24a Undulating rope 25 Lifting winch (traction mechanism)
25a Hook rope (rope)
26 Backstop 26a Cushioning spring 27 Counterweight 30 Gantry 31 Front leg 32 Rear leg 33 Lower spreader 34 Lower sheave 35 Upper spreader 36 Upper sheave 37 Pendant rope 40 Vibro device 41 Holding part 42 Vibration part 51 Load cell (distortion sensor)
52 Acceleration sensor 53 Display 60 Controller 61 Weight load identification unit 62 Vibration load identification unit 63 Judgment unit 64 Notification processing unit 100 Crawler crane

Claims (7)

A vibro device having a holding portion for holding a pile and a vibrating portion for vibrating the holding portion,
A main body including a traction mechanism that pulls a rope that suspends the vibro device, and
A vibration load specifying part that specifies the vibration load applied to the main body,
A pile pulling device including a determination unit for determining whether or not a load based on the vibration load specified by the vibration load specifying unit exceeds an allowable range. In the pile pulling device according to claim 1,
The pile pulling device includes a weight load specifying unit that specifies a weight load applied to the main body.
The determination unit is a pile pulling device characterized in that it determines whether or not a load based on the weight load and the vibration load exceeds an allowable range. In the pile pulling device according to claim 1 or 2.
The main body
The boom that supports the rope and
It is equipped with an acceleration sensor that detects the vibration acceleration of the boom.
The vibration load specifying unit is a pile pulling device characterized in that the vibration load is specified based on the vibration acceleration detected by the acceleration sensor. In the pile pulling device according to claim 3,
The main body
A support that undulates the boom and
One end is supported by the support and the other end is supported by the boom, and the back stop is provided to press the boom in a direction to lie down.
A pile pulling device characterized in that the acceleration sensor is arranged on the tip end side of the boom from the support position of the backstop. In the pile pulling device according to claim 2.
The main body
The boom that supports the rope and
It is provided with a strain sensor which is arranged on the downstream side in the propagation direction of vibration from the vibration generating portion to the main body from the tip of the boom and detects the strain of the boom.
The weight load specifying unit is a pile pulling device characterized in that the weight load is specified based on the strain of the boom detected by the strain sensor. In the pile pulling device according to claim 2.
A distortion sensor for detecting the distortion of the main body is provided.
The weight load specifying unit identifies the weight load based on the strain of the main body detected by the strain sensor.
The vibration load specifying unit is a pile pulling device characterized in that the vibration load is specified based on the strain of the main body detected by the strain sensor. In the pile pulling device according to any one of claims 1 to 6.
A pile pulling device including a notification processing unit that notifies when the determination unit determines that the allowable range is exceeded.

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