JP2023037761A - Ground hardness measuring device, and ground hardness measuring method - Google Patents

Abstract

To provide a ground hardness measuring device with high reliability of ground hardness measuring performance and a simple structure, and to provide a ground hardness measuring method with high reliability of ground hardness measuring performance.SOLUTION: A ground hardness measuring device comprises: a cylindrical case (3) equipped in a compaction machine; a shaft member (4) arranged in the case so as to ascend/descend; a weight (5) equipped in the shaft member; an acceleration sensor (6) attached to the weight; a shaft member driving mechanism (7) including a rack member (15) provided in the shaft member, an intermittent gear (16) capable of engaging with the rack member, and a plurality of gear members connected with the intermittent gear in a communication manner; a driving motor (8); and one or more energization springs (9) stretched between an upper end of the shaft member and the case. After driving the shaft member and the weight up to the upper limit position by the driving motor while elongating the energization spring, in a state where the engagement of the intermittent gear and the rack member is released, the shaft member and the weight are made to quickly fall to collide with a ground surface by using energization force of the energization spring, and an acceleration at the time of collision is measured by the acceleration sensor.SELECTED DRAWING: Figure 4

Description

The present invention relates to a ground hardness measuring device and a ground hardness measuring method for measuring the hardness of ground, and more particularly to a device and method suitable for measuring the hardness of ground compacted by a compaction machine. .

Various techniques have been adopted as techniques for measuring the hardness of the ground when the ground is compacted by a compaction machine.
In the ground density measurement system of Patent Document 1, the ground compacted by an excavator provided in the compaction machine is excavated, the volume and weight of the excavated soil are measured, and the ground density is calculated from the volume and weight. do.

In the compaction degree measuring device of Patent Document 2, a plate provided on the rolling roller so as to be able to contact the ground, an elastic wave measuring means provided on the plate, and this elastic wave measuring means. and computing means for computing data.

The measuring device of Patent Document 3 is a device that measures the state of vibration caused by the vibrator by striking the concrete when it is compacted by applying vibration to the concrete with the vibrator. It has a structure in which a sensor is incorporated and its surface is covered with a low-rigidity membrane member.

JP-A-2005-227233 JP-A-9-80032 JP 2017-31741 A

Although the ground density measurement system of Patent Document 1 can accurately measure the ground density, it requires a drilling device for drilling the ground and a measuring device for measuring the volume and weight of the excavated soil, which complicates the structure and increases manufacturing costs. becomes expensive.

In the compaction degree measuring device of Patent Document 2, since a plate is provided on the rolling roller so that it can contact the ground,
When the ground is not smoothly rolled, the plate is deformed unevenly and easily damaged, resulting in poor durability.

The measuring device of Patent Document 3 is a device that measures the vibration state of the concrete by driving it into the concrete when it is compacted by applying vibration to the concrete with the vibrator, so the hardness of the ground compacted by the compaction machine is measured. It is not measurable.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a ground hardness measuring device with a highly reliable function for measuring ground hardness and a simple structure, and to provide a highly reliable ground hardness measuring method. be.

A ground hardness measuring device according to claim 1 is a ground hardness measuring device for measuring the hardness of the ground, comprising a cylindrical case fixed to a construction machine in a vertical position, and a cylindrical case vertically penetrating the case. a weight mounted on the lower end of the shaft member; an acceleration sensor attached to the weight or the shaft member; a rack member provided on the shaft member; an intermittent gear meshable with a rack member; a shaft member drive mechanism including a plurality of gear members interlocked with the intermittent gear; a drive motor for driving the shaft member drive mechanism; one or a plurality of urging springs mounted on a case, the shaft member driving mechanism is driven by the drive motor, and the shaft member and the weight are moved to the upper limit position while extending the urging springs. , the intermittent gear and the rack member are disengaged from each other, and the biasing force of the biasing spring and the gravity acting on the shaft member and the weight cause the shaft member and the weight to descend rapidly to the ground. , and the acceleration at the time of collision is measured by an acceleration sensor. The construction machine includes a compaction machine.

According to the above configuration, after the shaft member and the weight are driven to the upper limit position, the biasing force of the biasing spring and the shaft member and the weight are applied in a state where the intermittent gear and the rack member are disengaged. The force of gravity causes the shaft member and the weight to descend rapidly and collide with the ground, and the acceleration at the time of collision is measured by an acceleration sensor. Since the deceleration when the member and the weight collide with the ground increases, the hardness of the ground can be measured with high accuracy, and the reliability of the function of measuring the hardness of the ground increases.
In addition, since this ground hardness measuring device is configured using members having a simple structure such as a case, a shaft member, a weight, a shaft member drive mechanism, a drive motor, and one or a plurality of urging springs, , which has a simple structure as a whole.

The ground hardness measuring device of claim 2 is a control unit connected to the drive motor and the acceleration sensor in the invention of claim 1, the control unit being capable of receiving a GPS signal and calculating a current position. , and is characterized by being able to repeatedly measure the hardness of the ground at predetermined time intervals while calculating the current position based on the GPS signal.

According to a third aspect of the present invention, there is provided a ground hardness measuring device according to the first aspect of the invention, wherein the rack member comprises a member attached to the shaft member.
According to a fourth aspect of the present invention, there is provided a ground hardness measuring device according to the first aspect of the invention, wherein the rack member is a part of the shaft member.
This configuration is advantageous because the shaft member and the rack member can be configured as one member.

According to a fifth aspect of the present invention, there is provided a ground hardness measuring apparatus according to the first aspect of the invention, wherein the construction machine is a compaction machine, and the drive motor is continuously driven to rotate during compaction work by the compaction machine. and is characterized in that the ground hardness measurement can be repeatedly executed at predetermined time intervals.
According to this configuration, it is possible to create a ground hardness map for the entire rolling area of the compaction machine.

The method for measuring the hardness of the ground according to claim 6 is a method for measuring the hardness of the ground, which comprises a cylindrical case fixed in a vertical position to the construction machine, and a cylindrical case that can be vertically moved through the case. a weight mounted on the lower end of the shaft member; an acceleration sensor attached to the weight or the shaft member; and 1 mounted between the shaft member and the case. Alternatively, a plurality of urging springs and a driving means capable of at least driving the shaft member upward are prepared in advance, and the urging spring is driven while driving the shaft member and the weight upward to the upper limit position by the driving means. and the shaft member and the weight are rapidly lowered by the biasing force of the biasing spring and the gravity acting on the shaft member and the weight to collide with the ground, and the acceleration at the time of collision is detected by an acceleration sensor. It is characterized by having a collision measurement step of measuring with.

The biasing spring is extended while driving the shaft member and the weight upward to the upper limit position by the driving means, and then the shaft member and the weight are combined with the biasing force of the biasing spring and the shaft member. It is possible to measure the hardness of the ground easily and reliably through two simple steps of making it crash into the ground by the gravity acting on the weight and measuring the acceleration at the time of impact with the accelerometer. Therefore, a highly reliable method for measuring the hardness of the ground can be realized.

1 is a perspective view of a ground hardness measuring device and a compaction machine according to an embodiment of the present invention; FIG. It is a front view of a ground hardness measuring device. FIG. 2 is a transverse cross-sectional view of the main part of the ground hardness measuring device; It is a front view of the principal part of a ground hardness measuring device. (A) is a front view of the main part when the shaft member of the ground hardness measuring device is at the lower limit position, (B) is a front view of the main part when the shaft member is at the middle position, and (C) is the shaft member at the upper limit. It is a front view of the main part at the time of the position. FIG. 5B is a view equivalent to FIG. 5B according to a modified example;

EMBODIMENT OF THE INVENTION Hereinafter, the form for implementing this invention is demonstrated based on drawing.
This ground hardness measuring device 1 is a device for measuring the hardness of ground compacted by a compaction machine R, which is a construction machine. It is fixed in a vertical position to the lower end of a holding member B fixed to W.

As shown in FIGS. 2 to 4, this measuring device 1 comprises a housing 2 fixed in a vertical position to a compaction machine R via a holding member B, and a housing 2 which is accommodated in the housing 2 and which is vertically positioned in the housing 2 . A cylindrical case 3 fixed to the body, a shaft member 4, a weight 5, an acceleration sensor 6, a shaft member drive mechanism 7, a drive motor 8, and one or more biasing springs 9 ing.

The housing 2 is made of a steel plate having a D-shaped horizontal cross section, and the upper flat surface of the housing 2 in a vertical position is fixed to the lower end of the holding member B as shown in FIG. The shaft member 4 penetrates the bottom wall of the housing 2 and protrudes downward. A pair of closing plates 10 for closing a pair of upper and lower inspection holes are fixed to the outer wall 2a of the housing 2 with four bolts 11. As shown in FIG.

The shaft member 4 is a shaft-shaped member made of steel and arranged in a vertical position. It is The weight 5 is fixed to the lower end of the shaft member 4 by, for example, screwing. The weight 5 is a steel member having a circular cross section with a larger diameter than the shaft member 4 and having a short vertical length.

The acceleration sensor 6 measures acceleration (deceleration) in the vertical direction and is incorporated inside the weight 5. A harness 13 connected to the acceleration sensor 6 passes through a harness introduction hole inside the shaft member 4. The harness 13 is led out from the upper end of the shaft member 4 and connected to a control unit 14 inside the housing 2 . A control panel for inputting command signals to the control unit 14 is provided near the driver's seat. The acceleration sensor 6 may be installed near the upper end of the shaft member 4 .

As shown in FIGS. 4 and 5 , the shaft member driving mechanism 7 includes a rack member 15 fixed to the side of the upper half of the shaft member 4 and having rack teeth, and an intermittent gear that can mesh with the rack member 15 . 16 and two gear members 17 and 18 interlocked with the intermittent gear 16 . The case 3 is formed with a slit through which the rack member 15 passes, and a notch (not shown) through which the rack member 15 is passed is formed at one place in the circumferential direction of the bearing 12a at the upper end of the case 3. ing.

The intermittent gear 16 is rotatably supported by the housing 2 . Gear teeth 16a that mesh with the rack teeth 15a of the rack member 15 are formed on the half circumference of the outer periphery of the intermittent gear 16, but the remaining half circumference is formed with a smooth cylindrical surface 16b without the gear teeth 16a. It is The circumferential length of the gear teeth 16 a is set shorter than the total length of the rack teeth 15 a of the rack member 15 .

As shown in FIG. 5A, when the shaft member 4 is at the lower limit position, the leading end of the gear tooth 16a of the intermittent gear 16 in the rotational direction is in mesh with the upper end of the rack tooth 15a of the rack member 15. When the intermittent gear 16 rotates in the direction of the arrow from this state, the rack member 15 and the shaft member 4 rise, and when the shaft member 4 reaches the upper limit position as shown in FIG. The trailing end of the gear tooth 16a in the rotational direction is engaged with the lower end portion of the rack tooth 15a. When the intermittent gear 16 rotates from this state, the smooth cylindrical surface 16b does not mesh with the rack teeth 15a, so the shaft member 4 and the weight 5 descend.

A speed reduction mechanism comprising a large-diameter gear 17 fixed coaxially to the intermittent gear 16 and having a diameter about half that of the intermittent gear 16 and a small-diameter gear 18 meshing with the large-diameter gear 17 is provided. is input to the small diameter gear 18, and the large diameter gear 17 and the intermittent gear 16 are rotationally driven. The drive motor 8 consists of an electric motor with a speed reducer. The drive motor 8 is supported by the housing 2 and is connected to the drive circuit of the control unit 14 and controlled by the control unit 14 . Incidentally, the drive motor 8 may be composed of a hydraulic motor.

Regarding the urging spring 9, a horizontal annular plate 20 is fixed to the upper end portion of the case 3, and a disc 21 is fixed to the upper end of the shaft member 4. For example, an urging spring 9 composed of four extension coil springs having a predetermined spring constant is mounted, and when the shaft member 4 is at the lower limit position, the urging spring 9 is in a free state without expansion and contraction.

As the shaft member 4 rises, the amount of extension of the biasing spring 9 increases. When the shaft member 4 reaches the upper limit position, the biasing spring 9 exerts a strong predetermined biasing force on the shaft member 4. be in a state to
As the biasing springs 9, less than four or more than four extension coil springs may be employed, or single or multiple large-diameter extension coil springs may be employed. It is also possible to

Next, a method for measuring ground hardness with the above-described ground hardness measuring device 1 will be described.
From the state shown in FIG. 5(A), the shaft member driving mechanism 7 is driven by the drive motor 8, and while the biasing spring 9 is extended, the shaft member 4 and the weight 5 are moved through the intermediate state shown in FIG. 5(B). is driven to the upper limit position shown in FIG. Gravity acting on the member 4 and the weight 5 causes the shaft member 4 and the weight 5 to drop sharply and collide with the ground, and the acceleration at the time of collision is measured by the acceleration sensor 6. - 特許庁
When the drive motor 8 is continuously rotated during compaction work, the sequence of FIG. 5(A)→FIG. 5(B)→FIG. 5(C)→FIG. 5(A) . . . The height measurement is repeatedly performed at predetermined time intervals. The predetermined time can be set based on the rotation speed of the drive motor 8 .

The control unit 14 has the function of calculating the hardness of the ground from the acceleration signal indicating the deceleration measured when the weight 5 collides, and the function of calculating the current position of the compaction machine R based on the GPS signal, Each time the hardness of the ground is repeatedly measured at predetermined time intervals, the information on the hardness of the ground and the position information are associated and stored in the memory.

While measuring the hardness of the ground in this way, when the compaction of the predetermined rolling area is completed, the predetermined rolling is performed based on the ground hardness information and the position information stored in the control unit 14. It is possible to create a map showing the ground hardness over the entire compaction area, in which the ground hardness is measured at small intervals in the running direction of the compaction machine R.

According to the ground hardness measuring device 1 described above, after the shaft member 4 and the weight 5 are driven to the upper limit position, the urging force of the urging spring 9 is Gravity acting on the shaft member 4 and the weight 5 causes the shaft member 4 and the weight 5 to drop rapidly and collide with the ground. , the deceleration when the shaft member 4 and the weight 5 collide with the ground increases, so the hardness of the ground can be measured with high accuracy, and the compaction of the ground The reliability of the function to measure the condition (ground hardness) is increased.

Further, the ground hardness measuring device 1 uses members having a simple structure such as the case 3, the shaft member 4, the weight 5, the shaft member drive mechanism 7, the drive motor 8, and one or more biasing springs 9. Since it is composed of

In the above, the case of measuring the hardness of the ground compacted by the compaction machine R was explained as an example.
When embanking while repeating embankment and compaction, when measuring the hardness of the ground after compaction, the current position is calculated based on the GPS signal, and the hardness of the ground is repeatedly measured at predetermined intervals. It may be configured to
Incidentally, the rolling compaction is not limited to that by the compaction machine, and includes rolling compaction by various construction machines. "Ground" is not limited to ordinary ground, but includes ground equivalents.

An example in which the above embodiment is partially modified will be described.
1) As shown in FIG. 6, instead of the rack member 15, it is also possible to configure a rack member 15A with a part of the shaft member 4. FIG.
2) In addition, a person skilled in the art can add various modifications to the above-described embodiment, and the present invention includes such modifications.

R: compaction machine,
1: Ground hardness measuring device 3: Case 4: Shaft member 5: Weight 6: Acceleration sensor 7: Shaft member drive mechanism 8: Drive motor 9: Biasing spring 15: Rack member 16: Intermittent gear 17: Large diameter Gear 18: Small diameter gear 15A: Rack member

Claims (6)

In a ground hardness measuring device for measuring the hardness of the ground,
a cylindrical case fixed in a vertical position to the construction machine;
a shaft member penetrating the case so as to be movable up and down;
a weight mounted on the lower end of the shaft member;
an acceleration sensor attached to the weight or shaft member;
a shaft member drive mechanism including a rack member provided on the shaft member, an intermittent gear meshable with the rack member, and a plurality of gear members interlocked with the intermittent gear;
a drive motor that drives the shaft member drive mechanism;
one or more biasing springs attached to the upper end of the shaft member and the case,
After driving the shaft member drive mechanism by the drive motor and driving the shaft member and the weight to the upper limit position while extending the biasing spring, the intermittent gear and the rack member are disengaged from each other. The shaft member and the weight are rapidly lowered by the biasing force of the biasing spring and the gravitational force acting on the shaft member and the weight to collide with the ground, and the acceleration at the time of collision is measured by the acceleration sensor. A ground hardness measuring device characterized by: a control unit connected to the drive motor and the acceleration sensor, the control unit being capable of receiving GPS signals and calculating a current position;
2. The ground hardness measuring device according to claim 1, wherein the ground hardness can be repeatedly measured at predetermined time intervals while calculating the current position based on the GPS signal. 2. The ground hardness measuring device according to claim 1, wherein the rack member is configured by a member attached to the shaft member. 2. The ground hardness measuring device according to claim 1, wherein the rack member comprises a part of the shaft member. The construction machine is a compaction machine, and the driving motor is continuously driven to rotate during compaction work by the compaction machine, so that ground hardness can be measured repeatedly at predetermined time intervals. The ground hardness measuring device according to claim 1. In the ground hardness measurement method for measuring the hardness of the ground,
A cylindrical case fixed to the construction machine in a vertical position, a shaft member penetrating the case so as to be able to move up and down, a weight attached to the lower end of the shaft member, the weight or preparing in advance an acceleration sensor attached to a shaft member, one or more biasing springs attached to the shaft member and the case, and driving means capable of at least driving the shaft member upward;
an ascending step of extending the biasing spring while driving the shaft member and the weight upward to an upper limit position by the driving means;
A collision measurement step of rapidly dropping the shaft member and the weight by the biasing force of the biasing spring and the gravity acting on the shaft member and the weight to collide with the ground, and measuring the acceleration at the time of collision with an acceleration sensor. and,
A method for measuring the hardness of the ground, comprising:

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