Construction management device for pile drivers

Abstract

To provide a construction management device of a pile driver which can continuously record a constructions status even in a sensor failure state.SOLUTION: A construction management device of a pile driver includes a control unit 33 for executing a construction management program on the basis of measurement results of a plurality of sensors, and a display for displaying the execution result of the construction management program, wherein a driving pressure sensor 35 for measuring a driving pressure of a hydraulic motor 31 for rotationally driving is provided on a base machine, and a control pressure sensor 36 for measuring a control pressure is provided on a rotationally driving device 26, a control unit determines a construction torque on the basis of the driving pressure and the control pressure, determines necessity of an emergency measure on the basis of the state of the control pressure sensor, fixes a control command for a solenoid proportional decompression valve 32 in the state where it is necessary for the emergency measure, and determines the construction torque on the basis of only the driving pressure, and the hydraulic motor for rotationally driving controls a displacement volume to the maximum, when the control command is fixed.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a construction management device for a pile driver, and more particularly to an emergency response in the event of a failure of the construction management device.

Background Art

[0002] Pile drivers for driving piles and ground improvement are equipped with a construction management device that stores a construction management program for controlling various construction methods. When pressing a construction member such as a steel pipe pile or a hollow rod into the ground, the construction management device executes the construction management program by a control device provided in the driver's cab, obtains each data representing the operating state from a plurality of sensors provided in various parts such as a leader and an auger, and obtains depth, speed, torque, rotation speed, etc. from each data and displays them on a display, and performs construction while recording them in a memory (see, for example, Patent Document 1).

[0003] Among pile drivers, small-sized ones generally use a hydraulic auger equipped with a variable displacement hydraulic motor. In this case, the construction torque is obtained based on the driving pressure and the motor volume. In addition, since the control pressure sensor necessary for grasping the volume of the motor is directly affected by the vibration generated in the auger, usually, one that satisfies the required performance such as durability is selected (see, for example, Patent Document 2).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] In recent years, with the expansion of the application range of pile drivers, such as the increase in the length and high output of piles, the importance of a construction management device that operates normally has been increasing. In particular, when using a small pile driver, if the control pressure sensor fails during construction, although excavation is possible without affecting the excavation ability, the construction torque cannot be recorded correctly, resulting in a situation where construction has to be interrupted.

[0006] Therefore, an object of the present invention is to provide a construction management device for a pile driver that can continue to record the construction status even in the event of a sensor failure.

Means for Solving the Problems

[0007] To achieve the above object, the first construction management device for a pile driver according to the present invention is mounted on a pile driver including a leader erected on a base machine equipped with a hydraulic pressure source and a rotary drive device capable of ascending and descending along the leader, and includes a control unit that executes a construction management program based on measurement results of a plurality of sensors, and a display that displays the execution result of the construction management program. In the construction management device, the rotary drive device includes a variable displacement hydraulic motor whose displacement can be changed by a control pressure, and an electromagnetic proportional pressure reducing valve that changes the control pressure based on a control command of the control unit. The plurality of sensors include a drive pressure sensor that measures the drive pressure of the variable displacement hydraulic motor, and a control pressure sensor that measures the control pressure. The drive pressure sensor is provided on the base machine, and the control pressure sensor is provided on the rotary drive device. The control unit obtains the construction torque based on the drive pressure and the control pressure, determines whether an emergency measure is required based on the state of the control pressure sensor, and when it is in a state where an emergency measure is required, fixes the control command and obtains the construction torque based only on the drive pressure. The variable displacement hydraulic motor is characterized in that when the control command is fixed, the displacement is adjusted to the maximum.

[0008] Further, the second construction management device of the pile driver of the present invention is mounted on a pile driver including a leader erected on a base machine equipped with a hydraulic power source and a rotary drive device capable of ascending and descending along the leader, and includes a control unit that executes a construction management program based on the measurement results of a plurality of sensors, and a display that displays the execution result of the construction management program. In the construction management device, the rotary drive device includes a variable displacement hydraulic motor whose displacement volume can be changed by a control pressure, and an electromagnetic proportional pressure reducing valve that changes the control pressure based on a control command of the control unit. The plurality of sensors include a drive pressure sensor that measures the drive pressure of the variable displacement hydraulic motor and a control pressure sensor that measures the control pressure. The drive pressure sensor and the control pressure sensor are respectively provided on the rotary drive device. The control unit obtains construction torque based on the drive pressure and the control pressure, determines whether an emergency measure is required based on the state of the control pressure sensor, and when it is in a state where an emergency measure is required, fixes the control command and obtains the construction torque based only on the drive pressure. The variable displacement hydraulic motor is characterized in that when the control command is fixed, the displacement volume is adjusted to the maximum.

Advantages of the Invention

[0009] According to the present invention, when the construction management device mounted on the pile driver is in a state where an emergency measure is required due to a failure of the control pressure sensor or the like, the control command for the electromagnetic proportional pressure reducing valve is fixed to adjust the displacement volume of the variable displacement hydraulic motor to the maximum. Therefore, even if the control pressure cannot be accurately grasped, it is possible to obtain the construction torque based on the set displacement volume and the drive pressure, and the construction that was conventionally on the verge of interruption can be completed emergently. Moreover, even in a situation where the excavation resistance suddenly increases, it is possible to surely excavate over a long excavation time with the maximum capacity of the rotary drive device, which is particularly beneficial as an emergency response peculiar to pile driving work in which the work progresses underground.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0011] Figures 1 to 3 are diagrams showing the application of the construction management device in the first exemplary form of the present invention to a small pile driver. As shown in Figure 1, the pile driver 11 is a dual-purpose machine that can switch between steel pipe pile construction and ground improvement construction, and includes a lower traveling body 12 equipped with crawlers, and a base machine 14 composed of an upper slewing body 13 rotatably provided on the lower traveling body 12, a leader 15 erected at the front of the upper slewing body 13, and a hoisting cylinder 16 that supports the leader 15 from the rear. Further, at the front of the upper slewing body 13, a leader support 17 that supports the leader 15 so as to be able to move up and down is provided, and above the front of the upper slewing body 13, a pipe support member 18 that supports pipes is provided. Furthermore, a driver's cab 19 is provided on the right side of the upper slewing body 13, and a power unit 20 equipped with an engine and a hydraulic pump serving as a hydraulic source is provided on the left side.

[0012] The leader 15 is formed by connecting a plurality of leader members having a square tube-shaped cross section to each other, and is rotatably attached to a lateral support shaft provided on the leader support 17. At the upper end of the leader 15, a top sheave 21 around which a lifting rope is wound is arranged, and at the lower front, an openable and closable anti-vibration member 23 for preventing the vibration of the steel pipe pile 22 is respectively arranged. In the center of the front surface of the leader 15, a rack gear 24 is provided as a component of a rack and pinion type lifting device, and on both front end portions of the side surfaces, a pair of left and right guide pipes 25, 25 are continuously provided over the entire length of the leader 15, which serves as a mounting portion for a hydraulic auger 26 which is an example of a rotary drive device.

[0013] Each leader member is formed by abutting connection flanges corresponding to the cross-sectional shape of the leader 15 at adjacent portions, and is stably connected using a plurality of bolts and nuts. Each flange connection portion has the same structure with the same shape of the connection flange, bolt hole size, arrangement pitch, etc. By removing the bolts and nuts to release the flange connection, although illustration is omitted, it is possible to recombine into a long specification with a large number of leader members and a short specification with a small number of leader members. In this case, the lengths of the plurality of hydraulic hoses 27 connecting between the upper swing body 13 and the auger 26 are changed according to the leader length.

[0014] The hydraulic hose 27 is routed along the leader 15 via a pipe support member 18 rising from the upper swing body 13, and the portion beyond the pipe support member 18 is unrestrainedly connected to the concentrator connector 28 of the auger 26. This unrestrained portion has a substantially U-shaped slack 27a and is movable vertically following the elevation of the auger 26, and its length is set according to when the height position of the auger 26 is at its maximum (Fig. 1). Thereby, when the auger 26 reaches the upper end portion (lifting limit position) or the lower end portion (lowering limit position) of the leader 15, the shape of the slack 27a does not deform excessively.

[0015] The auger 26 is configured around a device body 26a rotatably provided with a drive shaft 29, and a pair of left and right guide gibs 26b, 26b slidably contacting the guide pipes 25, 25 of the leader 15 protrude rearward. By rotationally driving a pair of left and right pinions (not shown) meshing with the rack gear 24 by a hydraulic motor 30 for elevation, the auger 26 moves up and down along the front surface of the leader 15.

[0016] In addition, the auger 26 includes a rotary drive hydraulic motor 31 connected to a speed reduction mechanism within the apparatus main body 26a, and an electromagnetic proportional pressure reducing valve 32 attached thereto. The rotary drive hydraulic motor 31 is a swash plate type variable displacement hydraulic motor capable of changing its displacement by changing the tilt angle of the swash plate. The tilt angle of the swash plate, that is, the displacement volume (discharge volume per motor rotation) is adjusted by a regulator. This regulator is controlled by the control pressure output from the electromagnetic proportional pressure reducing valve 32.

[0017] As shown in FIG. 2, the electromagnetic proportional pressure reducing valve 32 changes the control pressure based on a control command from the control unit 33 of the construction management device described later. Specifically, it is configured to change the pressure reduction degree as the control current input to the solenoid increases or decreases. When a control command is input, the generated command pilot pressure (secondary pressure) increases, and the displacement volume is gradually decreased by the operation of the regulator to operate the motor. On the other hand, when the control command is fixed to the minimum (for example, the control current is cut off), the displacement volume is adjusted to the maximum to operate the motor. That is, although there is a proportional relationship between the control current and the control pressure of the electromagnetic proportional pressure reducing valve 32, there is an inverse proportional relationship between the control pressure and the displacement volume. As a result, if the flow rate is constant, the rotary drive hydraulic motor 31 rotates at a higher speed when the displacement volume is smaller, and the rotational speed decreases when the displacement volume is larger. However, since it rotates using a large amount of hydraulic oil, it generates a large torque.

[0018] Here, when the pile driver 11 is used for the purpose of driving a steel pipe pile, the steel pipe pile 22 is used as the construction member. The steel pipe pile 22 is connected via an adapter 34 provided at the lower end of the drive shaft 29, and is press-fitted into the ground by lowering the auger 26 while rotating the drive shaft 29. When the pile driver 11 is used for the purpose of ground improvement, a hollow rod (not shown) is used as the construction member. The upper end of the hollow rod is connected to a swivel above the auger 26, and the lower end is connected to an excavation head. While rotating this hollow rod, a ground improvement agent such as cement milk injected from the tip of the excavation head through the hollow rod is injected into the ground.

[0019] In order to perform various construction methods such as driving these piles and ground improvement, in the cab 19, devices such as operation levers, operation pedals, push-button switches, and touch panel displays for performing operations such as traveling, turning, and driving the lifting and rotation of the auger 26 are intensively arranged near the driver's seat in consideration of operability. Furthermore, a construction management device electrically connected to these devices and operation sensors of the pile driver 11 is installed.

[0020] The construction management device is mainly composed of a control unit (CPU) 33 that executes a construction management program for controlling various construction methods and performs arithmetic processing such as data processing and determination. It includes a FLASH ROM that stores the construction management program, a RAM that temporarily stores various data during processing, a storage unit that stores construction plan data such as the planned pile driving position and target depth at the construction site and various data during actual construction created by executing the construction management program, and a display for the driver to confirm the execution result of the construction management program on the display screen or input data by touch panel operation.

[0021] Examples of the plurality of sensors constituting the operation sensor of the auger 26 include a torque sensor, a depth sensor, and a rotation sensor. For example, the torque sensor is a sensor that measures the torque of the construction member held by the auger 26, and as shown in FIG. 2, it consists of a drive pressure sensor 35 that measures the drive pressure (pump load pressure) of the rotation drive hydraulic motor 31 and a control pressure sensor 36 that measures the control pressure. The drive pressure sensor 35 is provided on the upper swing body 13 and measures the pressure at the outlet of the main hydraulic pump 37. On the other hand, the control pressure sensor 36 is provided on the auger 26 and measures the pressure obtained by reducing the pressure oil from the pilot hydraulic pump 38 with the electro-hydraulic proportional pressure reducing valve 32.

[0022] The signals measured by the respective sensors are transmitted to the control unit 33. For example, based on the driving pressure of the hydraulic motor 31 for rotational drive and the displacement volume corresponding to the control pressure, the construction torque is calculated as the construction load. The depth, integrated rotation speed, and rotational speed are also calculated based on the signals measured by encoders, proximity sensors, etc. provided in each part.

[0023] When driving a pile (burying a steel pipe) using the construction management device configured as described above, with the pile driver 11 moved to the construction site, the display of the construction management device is switched to the construction screen, and the pile driving operation is carried out as planned until the target depth is reached while creating construction data. The operator's driving operation is, for example, to tilt the lever to perform the right rotation operation and the lowering operation of the auger 26, and while maintaining the driving operation, operate the volume for torque adjustment according to the excavation resistance. Here, at the start of excavation, the torque is set small and the rotation speed is increased to prioritize efficient construction. Then, as the target depth is approached and the ground becomes harder, the excavation resistance increases and the rotation speed of the auger 26 decreases, so the volume is increased and the torque is gradually increased.

[0024] At this time, the control unit 33 calculates the construction torque based on the driving pressure of the hydraulic motor 31 for rotational drive and the displacement volume corresponding to the control pressure, and displays "construction torque" on the screen together with "pile number", "target depth", etc. This display is represented, for example, by a line graph in two-dimensional coordinates with the depth on the vertical axis and the magnitude of the construction torque on the horizontal axis, and is a display for knowing the ground conditions, that is, a display that enhances the operator's predictability. Simultaneously with such real-time display, the construction torque for each depth and the target pile number are associated and sequentially stored in the storage unit of the construction management device.

[0025] Incidentally, in recent years, with the expansion of the application range of the pile driver 11, such as the increase in the length and output of piles, the importance of a construction management device that operates normally has been increasing. In particular, when using a small pile driver, if the control pressure sensor 36 necessary for grasping the motor volume fails, the construction torque cannot be recorded correctly, resulting in a situation where construction has to be interrupted. Therefore, the construction management device of the pile driver 11 is equipped with a function to take emergency measures when the control pressure sensor 36 fails by executing an additional control program. Hereinafter, the specific operation of the emergency response will be described with reference to FIGS. 2 and 3.

[0026] As shown in FIG. 2, the control unit 33 obtains the construction torque according to the operation of the pile driver 11 and monitors the state to determine whether the signal from the control pressure sensor 36 is within the normal range, that is, whether emergency measures are required. For example, when the control pressure sensor 36 fails due to aging deterioration, the control unit 33 detects the abnormal signal and determines that it is in a state where emergency measures are required. In this case, as shown in FIG. 3, the control unit 33 ignores the signal from the control pressure sensor 36 and switches to a state where it is not required to receive, and fixes the control command to the electromagnetic proportional pressure reducing valve 32 to the minimum. In other words, the control current is cut off, and the control to obtain the construction torque is performed based only on the driving pressure of the rotary drive hydraulic motor 31. As a result, the rotary drive hydraulic motor 31 adjusts the ejection volume to the maximum, operates the motor, and continues the construction of the pile driver 11 at a low speed while outputting the maximum torque.

[0027] Thus, according to the first configuration of the present invention, when the construction management device mounted on the pile driver 11 is in a state requiring emergency measures due to a failure of the control pressure sensor 36 or the like, the control command for the electromagnetic proportional pressure reducing valve 32 is fixed and the displacement volume of the variable displacement hydraulic motor 31 is adjusted to the maximum. Therefore, even if the control pressure cannot be accurately grasped, the construction torque can be obtained based on the set displacement volume and the driving pressure. Thus, construction can be completed emergently even in a situation where it was conventionally necessary to interrupt. Moreover, even when placed in a situation where the excavation resistance suddenly increases due to the ground conditions, excavation can be reliably performed over a long excavation time with the maximum capacity of the rotary drive device 26. Therefore, it is particularly useful as an emergency response peculiar to pile construction where work progresses underground.

[0028] In addition, while the control pressure sensor 36 is provided in the rotary drive device 26, the drive pressure sensor 35 is provided in the base machine 14 (for example, under the floor of the driver's seat) that is not directly affected by vibrations, rainwater, etc. Therefore, it is possible to reduce the risk of failure of the drive pressure sensor 35, which contributes to ensuring the quality of construction management.

[0029] FIG. 4 and FIG. 5 show a second exemplary embodiment of the construction management device of the pile driver 11 of the present invention. In the following description, the same reference numerals are given to the components identical to those of the construction management device shown in the first exemplary embodiment, and detailed description thereof is omitted.

[0030] The construction management device shown in the second exemplary form changes only the mounting position of the driving pressure sensor with respect to the configuration of the first exemplary form. As shown in FIG. 4, the driving pressure sensor 39 is provided on the auger 26 in the same manner as the control pressure sensor 36, and a pair of two measures the differential pressure (pressure difference between the primary pressure and the secondary pressure) at the inlet and outlet of the rotary drive hydraulic motor 31. The control unit 33 determines the driving pressure of the rotary drive hydraulic motor 31 based on the measured differential pressure, and calculates the construction torque based on this driving pressure and the pushing volume corresponding to the control pressure. Further, the control unit 33 determines whether an emergency measure is necessary based on the state of the control pressure sensor 36. As shown in FIG. 5, when it is a failure state that requires an emergency measure, the signal from the control pressure sensor 36 is ignored and switched to a reception-unnecessary state, and the control command to the electromagnetic proportional pressure reducing valve 32 is fixed to the minimum, and control is performed to obtain the construction torque based only on the driving pressure of the rotary drive hydraulic motor 31.

[0031] And also in the present exemplary form configured in this way, even in a situation where the control pressure sensor 36 fails and construction conventionally has to be interrupted, construction can be completed emergently. Further, in the case of the present exemplary form, since the driving pressure sensor 39 is provided on the auger 26, it is possible to suppress the influence of the pressure loss in the hydraulic circuit, and a construction management device suitable for the needs of construction management that emphasizes high accuracy, longer pile lengths, and higher output is achieved.

[0032] Note that the present invention is not limited to the above-described exemplary forms, and the emergency response based on the state of the control pressure sensor may be a simple configuration that is added to an existing construction management device to function, and can be appropriately changed according to the specifications of the pile driver. Further, in the embodiment, the steel pipe embedding is described as an example, but the present invention is not limited to this, and it can also be applied to ground improvement.

Explanation of reference numerals

[0033] 11…Piling machine, 12…Lower traveling body, 13…Upper slewing body, 14…Base machine, 15…Leader, 16…Lifting cylinder, 17…Leader support, 18…Pipe support member, 19…Operator's cab, 20…Power unit, 21…Top sheave, 22…Steel pipe pile, 23…Anti-vibration member, 24…Rack gear, 25…Guide pipe, 26…Auger, 26a…Equipment body, 26b…Guide gib, 27…Hydraulic hose, 27a…Slack, 28…Central connector, 29…Drive shaft, 30…Hydraulic motor for lifting, 31…Hydraulic motor for rotary drive, 32…Electromagnetic proportional pressure reducing valve, 33…Control unit, 34…Adapter, 35…Drive pressure sensor, 36…Control pressure sensor, 37…Main hydraulic pump, 38…Pilot hydraulic pump, 39…Drive pressure sensor

Claims

1. An installation management device mounted on a pile driver including a reader erected on a base machine equipped with a hydraulic power source and a rotary drive device capable of moving up and down along the reader, the installation management device comprising: a control unit that executes a construction management program based on measurement results of a plurality of sensors; and a display that displays an execution result of the construction management program. The rotary drive device includes a variable displacement hydraulic motor whose displacement can be changed by a control pressure, and an electromagnetic proportional pressure reducing valve that changes the control pressure based on a control command from the control unit. The plurality of sensors include a drive pressure sensor that measures a drive pressure of the variable displacement hydraulic motor and a control pressure sensor that measures the control pressure. The drive pressure sensor is provided on the base machine, and the control pressure sensor is provided on the rotary drive device. The control unit obtains construction torque based on the drive pressure and the control pressure, determines whether an emergency measure is necessary based on a state of the control pressure sensor, and when it is determined that an emergency measure is necessary, fixes the control command and obtains the construction torque based only on the drive pressure. The variable displacement hydraulic motor is characterized in that when the control command is fixed, the displacement is adjusted to a maximum.

2. An installation management device mounted on a pile driver including a reader erected on a base machine equipped with a hydraulic power source and a rotary drive device capable of moving up and down along the reader, the installation management device comprising: a control unit that executes a construction management program based on measurement results of a plurality of sensors; and a display that displays an execution result of the construction management program. The rotary drive device includes a variable displacement hydraulic motor whose displacement can be changed by a control pressure, and an electromagnetic proportional pressure reducing valve that changes the control pressure based on a control command from the control unit. The plurality of sensors include a drive pressure sensor that measures a drive pressure of the variable displacement hydraulic motor and a control pressure sensor that measures the control pressure. The drive pressure sensor and the control pressure sensor are provided on the rotary drive device. The control unit obtains construction torque based on the drive pressure and the control pressure, determines whether an emergency measure is necessary based on a state of the control pressure sensor, and when it is determined that an emergency measure is necessary, fixes the control command and obtains the construction torque based only on the drive pressure. The variable displacement hydraulic motor is a construction management device characterized in that when the control command is fixed, the displacement volume is adjusted to the maximum.

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