JP7709892B2 - Pile driver construction management device - Google Patents

Description

The present invention relates to a construction management device for a pile driver, and more specifically, to emergency response measures in the event of a breakdown in the construction management device.

A pile driver used for burying piles and improving ground is equipped with a construction management device that stores a construction management program for controlling various construction methods. When driving construction components such as steel pipe piles and hollow rods into the ground, the construction management device executes the construction management program using a control device installed in the driver's cab, obtains data indicating the operating status from multiple sensors installed in various parts such as the leader and auger, and calculates depth, speed, torque, rotation speed, etc. from each data, displays them on the display, and records them in memory while carrying out construction (see, for example, Patent Document 1).

Small pile drivers generally use hydraulic augers equipped with variable displacement hydraulic motors, in which case the construction torque is calculated based on the drive pressure and motor volume. In addition, the control pressure sensor required to grasp the motor volume is directly affected by the vibrations generated by the auger, so one that meets the required performance such as durability is usually selected (for example, see Patent Document 2).

JP 2017-190579 A JP 2019-199760 A

In recent years, the scope of application of pile drivers has expanded, with pile lengths and higher output, and so on, making it increasingly important for construction management devices to operate normally. Particularly when using small pile drivers, if the control pressure sensor fails during construction, it will not affect the excavation capacity and construction can continue, but construction will have to be stopped because the construction torque cannot be recorded correctly.

The present invention aims to provide a construction management device for a pile driver that can continue recording the construction status even if the sensor fails.

In order to achieve the above object, the first construction management device for a pile driver of the present invention is mounted on a pile driver equipped with a reader that is erected on a base machine equipped with a hydraulic power source and a rotary drive device that can be raised and lowered along the reader, and is equipped with a control unit that executes a construction management program based on the measurement results of multiple sensors, and a display that displays the execution results of the construction management program. In this construction management device, the rotary drive device is equipped with a variable displacement hydraulic motor that can change the displacement volume by the control pressure, and an electromagnetic proportional pressure reducing valve that changes the control pressure based on a control command from the control unit, and the multiple sensors are equipped with a variable displacement hydraulic motor that can change the displacement volume by the control pressure, and ... command from the control unit. The system includes a driving pressure sensor that measures the driving pressure of the motor and a control pressure sensor that measures the control pressure, with the driving pressure sensor provided on the base machine and the control pressure sensor provided on the rotary drive device, and the control unit determines the application torque based on the driving pressure and the control pressure, and determines whether emergency measures are required based on the state of the control pressure sensor. When emergency measures are required, the control command is fixed and the application torque is determined based only on the driving pressure, and the variable displacement hydraulic motor is characterized in that the displacement volume is adjusted to a maximum when the control command is fixed.

In addition, the second construction management device for a pile driver of the present invention is mounted on a pile driver equipped with a reader that is erected on a base machine equipped with a hydraulic power source and a rotary drive device that can be raised and lowered along the reader, and is equipped with a control unit that executes a construction management program based on the measurement results of multiple sensors, and a display that displays the execution results of the construction management program. In this construction management device, the rotary drive device is equipped with a variable displacement hydraulic motor that can change the displacement volume by the control pressure, and an electromagnetic proportional pressure reducing valve that changes the control pressure based on a control command from the control unit, and the multiple sensors are The motor includes a driving pressure sensor that measures the driving pressure of the motor, and a control pressure sensor that measures the control pressure. The driving pressure sensor and the control pressure sensor are provided on the rotary drive device, respectively. The control unit calculates the application torque based on the driving pressure and the control pressure, and determines whether emergency measures are required based on the state of the control pressure sensor. When emergency measures are required, the control command is fixed and the application torque is calculated based only on the driving pressure. The variable displacement hydraulic motor is characterized in that the displacement volume is adjusted to a maximum when the control command is fixed.

According to the present invention, when the construction management device installed in the pile driver is in a state requiring emergency measures due to a failure of the control pressure sensor or the like, the control command for the electromagnetic proportional pressure reducing valve is fixed and the displacement volume of the variable displacement hydraulic motor is adjusted to the maximum, so that even if the control pressure cannot be accurately grasped, it is possible to calculate the construction torque based on the set displacement volume and driving pressure, and construction that would have been forced to be suspended in a temporary manner can be completed. Moreover, even in a situation where the excavation resistance suddenly increases, excavation can be performed reliably over a long period of time at the maximum capacity of the rotary drive device, which is particularly useful as an emergency response specific to pile construction where work is carried out underground.

1 is a side view of a pile driver to which a construction management device in a first embodiment of the present invention is applied. FIG. FIG. 11 is an explanatory diagram showing a failure state of the control pressure sensor. FIG. 11 is a diagram showing a control circuit in a second embodiment of the present invention. FIG. 11 is an explanatory diagram showing a failure state of the control pressure sensor.

Figures 1 to 3 are diagrams showing the application of the construction management device in the first embodiment 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 is equipped with a base machine 14 consisting of a lower running body 12 equipped with crawlers and an upper rotating body 13 that is rotatably mounted on the lower running body 12, a leader 15 erected at the front of the upper rotating body 13, and a hoisting cylinder 16 that supports the leader 15 from the rear. In addition, a leader support 17 that supports the leader 15 so that it can be raised and lowered is provided at the front of the upper rotating body 13, and a pipe support member 18 that supports the pipes is provided above the front of the upper rotating body 13. In addition, a driver's cab 19 is provided on the right side of the upper rotating body 13, and a power unit 20 equipped with an engine and a hydraulic pump that serves as a hydraulic source is provided on the left side.

The leader 15 is made up of multiple interconnected leader members, each with a rectangular cylindrical cross section, and is rotatably attached to a support shaft in the width direction of the vehicle provided on the leader support 17. A top sheave 21 around which a lifting rope is wound is provided at the upper end of the leader 15, and an openable and closable anti-vibration member 23 for preventing the steel pipe pile 22 from swinging is provided at the front of the lower part. A rack gear 24 is provided at the center of the front of the leader 15 as a component of a rack and pinion type lifting device, and a pair of left and right guide pipes 25, 25 are provided continuously over the entire length of the leader 15 at the front ends of both sides, and serve as the mounting part for a hydraulic auger 26, which is an example of a rotary drive device.

Each leader member is formed by abutting connecting flanges that correspond to the cross-sectional shape of the leader 15 at adjacent portions, and is stably connected using multiple bolts and nuts. Each flange connection has the same structure with a common shape of the connecting flange, bolt hole size, arrangement pitch, etc., and by removing the bolts and nuts to release the flange connection, it is possible to rearrange it into a long specification consisting of many leader members, or a short specification consisting of a small number of leader members (not shown in the figure). In this case, the length of the multiple hydraulic hoses 27 connecting between the upper rotating body 13 and the auger 26 is changed to match the leader length.

The hydraulic hose 27 is routed along the leader 15 via the pipe support member 18 that rises from the upper rotating body 13, and the portion beyond the pipe support member 18 is connected unconstrained to the central connector 28 of the auger 26. This unconstrained portion has a roughly U-shaped slack 27a and can move up and down following the rise and fall of the auger 26, and its length is set to match the maximum height position of the auger 26 (Figure 1). This prevents the shape of the slack 27a from being excessively deformed when the auger 26 reaches the upper end (upward limit position) or the lower end (downward limit position) of the leader 15.

The auger 26 is configured around a device body 26a equipped with a rotatable drive shaft 29, and has a pair of left and right guide gibs 26b, 26b that protrude rearward and slide against the guide pipes 25, 25 of the leader 15. The auger 26 moves up and down along the front of the leader 15 by rotating a pair of left and right pinions (not shown) that mesh with the rack gear 24 using a lifting hydraulic motor 30.

The auger 26 also includes a rotary drive hydraulic motor 31 connected to a reduction mechanism in the device body 26a, and an electromagnetic proportional pressure reducing valve 32 attached to the rotary drive hydraulic motor 31. The rotary drive hydraulic motor 31 is a swash plate type variable displacement hydraulic motor whose capacity can be changed by changing the tilt angle of the swash plate. The tilt angle of the swash plate, i.e., 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.

As shown in FIG. 2, the electromagnetic proportional pressure reducing valve 32 changes the control pressure based on the control command of the control unit 33 of the construction management device described later. Specifically, it is configured to change the degree of pressure reduction according to the increase or decrease in the control current input to the solenoid. When a control command is input, the generated command pilot pressure (secondary pressure) increases, and the motor is operated by gradually reducing the displacement volume by the operation of the regulator. On the other hand, when the control command is fixed at a minimum (for example, the control current is turned off), the motor is operated by adjusting the displacement volume to a maximum. In other words, the control current and control pressure of the electromagnetic proportional pressure reducing valve 32 are proportional to each other, but the control pressure and displacement volume are inversely proportional to each other. As a result, if the flow rate is constant, the smaller the displacement volume, the faster the motor rotates, and the larger the displacement volume, the slower the rotation speed becomes, but since it uses a lot of hydraulic oil to rotate, it generates a large torque.

When the pile driver 11 is used for the purpose of burying steel pipe piles, a 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 pressed 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 the excavation head. While the hollow rod is being rotated, a ground improvement agent such as cement milk is sprayed from the tip of the excavation head through the hollow rod and injected into the ground.

In order to carry out various construction methods such as burying piles and ground improvement work, the cab 19 is equipped with devices such as control levers and pedals for driving, turning, raising and lowering the auger 26, as well as push button switches and a touch panel display, all of which are concentrated near the driver's seat for ease of use. In addition, a construction management device is installed that is electrically connected to these devices and the pile driver 11's operation sensor.

The construction management device is composed of a control unit (CPU) 33 that executes construction management programs for controlling various construction methods and performs calculations such as data processing and judgments, and is equipped with a flash ROM that stores the construction management program, a RAM that temporarily stores various data being processed, a memory unit that stores construction plan data that sets the planned buried positions and target depths of piles at the construction site, and various data created by executing the construction management program during the actual construction, and a display that allows the operator to check the results of the execution of the construction management program on a display screen and enter data using a touch panel.

The multiple sensors that make up 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 gripped by the auger 26, and as shown in FIG. 2, it is composed of a driving pressure sensor 35 that measures the driving pressure (pump load pressure) of the rotary drive hydraulic motor 31, and a control pressure sensor 36 that measures the control pressure. The driving pressure sensor 35 is provided on the upper rotating 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 by the electromagnetic proportional pressure reducing valve 32.

The signals measured by each sensor are transmitted to the control unit 33, and the construction torque is calculated as the construction load, for example, based on the driving pressure of the rotary drive hydraulic motor 31 and the displacement volume corresponding to the control pressure. The depth, cumulative number of rotations, and rotation speed are also calculated based on signals measured by encoders and proximity sensors installed in each part.

When performing pile construction (steel pipe burial) using a construction management device configured in this manner, the pile driver 11 is moved to the construction site, the display of the construction management device is switched to the construction screen, and pile driving work proceeds as planned until the target depth is reached while creating construction data. The operator operates the lever, for example, to rotate the auger 26 to the right and lower it, and while maintaining the operation, operates the volume for adjusting the torque according to the excavation resistance. Here, the torque is reduced at the start of excavation and the rotation speed is increased to proceed with construction with an emphasis on efficiency. 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 to gradually increase the torque.

At this time, the control unit 33 calculates the construction torque based on the driving pressure of the rotary drive hydraulic motor 31 and the displacement volume corresponding to the control pressure, and displays the "construction torque" on the screen together with the "pile number" and "target depth". This display is, for example, shown as a two-dimensional line graph with the vertical axis representing depth and the horizontal axis representing the magnitude of the construction torque, and is a display that allows the operator to know the ground condition, i.e., a display that increases the operator's predictability. At the same time as this real-time display, the construction torque for each depth is associated with the target pile number and sequentially stored in the memory unit of the construction management device.

In recent years, the application range of the pile driver 11 has expanded, with longer pile lengths and higher output, and so on, making it increasingly important for the construction management device to operate normally. In particular, when using a small pile driver, if the control pressure sensor 36 required to grasp the motor volume fails, the construction torque cannot be recorded correctly, and construction must be stopped. Therefore, the construction management device of the pile driver 11 is equipped with a function for taking emergency measures in the event of a failure of the control pressure sensor 36 by executing an additional control program. The specific operation of the emergency response will be described below with reference to Figures 2 and 3.

As shown in FIG. 2, the control unit 33 determines 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, i.e., whether emergency measures are required. For example, if the control pressure sensor 36 becomes faulty due to aging, the control unit 33 detects the abnormal signal and determines that 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 in which it does not need to receive it, fixes the control command to the electromagnetic proportional pressure reducing valve 32 to a minimum, in other words, turns off the control current, and performs control to determine the construction torque based only on the driving pressure of the rotary drive hydraulic motor 31. As a result, the rotary drive hydraulic motor 31 adjusts the displacement volume to the maximum and operates the motor, allowing the pile driver 11 to continue construction at a low speed while outputting the maximum torque.

Thus, according to the first configuration of the present invention, when the construction management device installed in 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, so that even if the control pressure cannot be accurately grasped, it is possible to calculate the construction torque based on the set displacement volume and driving pressure, and construction can be completed in an emergency even in a situation where construction would have had to be interrupted in the past. Moreover, even if the ground conditions suddenly cause an increase in excavation resistance, excavation can be completed reliably over a long period of time at the maximum capacity of the rotary drive device 26, which is particularly useful as an emergency response specific to pile construction where work is carried out underground.

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 (e.g., under the floor of the driver's seat) where it is not directly affected by vibrations or rainwater, which reduces the risk of failure of the drive pressure sensor 35 and contributes to ensuring the quality of construction management.

Figures 4 and 5 show a second embodiment of the construction management device for the pile driver 11 of the present invention. In the following description, the same components as those in the construction management device shown in the first embodiment are given the same reference numerals and detailed description is omitted.

The construction management device shown in the second embodiment has only the mounting position of the driving pressure sensor changed from the configuration of the first embodiment. 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 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 in a pair. 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 the driving pressure and the displacement volume corresponding to the control pressure. In addition, the control unit 33 determines whether emergency measures are required based on the state of the control pressure sensor 36, and when a failure state requiring emergency measures is detected as shown in FIG. 5, the control unit 33 ignores the signal from the control pressure sensor 36 and switches to a state in which it is not necessary to receive it, and fixes the control command to the electromagnetic proportional pressure reducing valve 32 to a minimum, and performs control to determine the construction torque based only on the driving pressure of the rotary drive hydraulic motor 31.

In this embodiment, which is configured in this manner, even if the control pressure sensor 36 fails, construction can be completed in a timely manner, even in a situation where construction would have had to be interrupted in the past. Furthermore, in this embodiment, the drive pressure sensor 39 is provided on the auger 26, so it is possible to reduce the effects of pressure loss in the hydraulic circuit, achieving a construction management device that emphasizes high accuracy in construction management, and meets the needs for longer pile lengths and higher output.

The present invention is not limited to the above-mentioned embodiments, and the emergency response based on the state of the control pressure sensor can be implemented simply by adding it to an existing construction management device, and can be modified as appropriate according to the specifications of the pile driver. In addition, the embodiment has been described using the example of burying steel pipes, but the present invention is not limited to this and can also be applied to ground improvement work.

11...pile driver, 12...lower running body, 13...upper rotating body, 14...base machine, 15...leader, 16...elevation 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...device body, 26b...guide gib, 27...hydraulic hose, 27a...slack, 28...central connector, 29...drive shaft, 30...lifting hydraulic motor, 31...rotation drive hydraulic motor, 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 (2)

A construction management device is mounted on a pile driver equipped with a reader that is erected on a base machine equipped with a hydraulic power source and a rotary drive device that can be raised and lowered along the reader, the device comprising a control unit that executes a construction management program based on measurement results from a plurality of sensors, and a display that displays the execution results of the construction management program,
the rotary drive device includes a variable displacement hydraulic motor capable of changing a displacement volume 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 driving pressure sensor that measures a driving pressure of the variable displacement hydraulic motor and a control pressure sensor that measures the control pressure, the driving pressure sensor being provided on the base machine and the control pressure sensor being provided on the rotary drive device,
The control unit calculates a working torque based on the driving pressure and the control pressure, and determines whether or not emergency measures are required based on the state of the control pressure sensor. When emergency measures are required, the control command is fixed, and the working torque is calculated based only on the driving pressure.
A construction management device characterized in that the variable displacement hydraulic motor is adjusted so that the displacement volume is maximized when the control command is fixed. A construction management device is mounted on a pile driver equipped with a reader that is erected on a base machine equipped with a hydraulic power source and a rotary drive device that can be raised and lowered along the reader, the device comprising a control unit that executes a construction management program based on measurement results from a plurality of sensors, and a display that displays the execution results of the construction management program,
the rotary drive device includes a variable displacement hydraulic motor capable of changing a displacement volume 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 driving pressure sensor that measures a driving pressure of the variable displacement hydraulic motor and a control pressure sensor that measures the control pressure, the driving pressure sensor and the control pressure sensor being provided in the rotary drive device,
The control unit calculates a working torque based on the driving pressure and the control pressure, and determines whether or not emergency measures are required based on the state of the control pressure sensor. When emergency measures are required, the control command is fixed, and the working torque is calculated based only on the driving pressure.
A construction management device characterized in that the variable displacement hydraulic motor is adjusted so that the displacement volume is maximized when the control command is fixed.