JP3898986B2 - Automatic penetration testing machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is an automatic penetration testing machine that measures the basic data of the ground in order to know the ground strength of the ground, and in particular, it penetrates naturally by load, so-called self-sinking and forced penetration by rotation of the rod. The present invention relates to an automatic penetrating tester that is configured to change the operation when it is determined.
[0002]
[Prior art]
Conventionally, when building various types of structures, it is extremely important to investigate the geology of the ground of the land and to know the ground strength of the land, and such ground geology is generally investigated by conducting a boring test. However, when building a small building such as the previous stage or a house, a penetration test is conducted for a depth of up to about 15 m in the ground as a simple geological survey. In this penetration test, various types of penetration testing machines that use the weight of the weight and rotational force to the rod to penetrate into the ground are used. As shown in FIG. The lifting / lowering base 107 is capable of moving up and down along with a weight 131 having a predetermined weight. The lifting / lowering base 107 includes a chuck portion 108 for holding the rod 127, and a chuck portion 108. A rotational driving source such as a motor 120 for rotational driving is disposed. At the time of the penetration test, a weight 131 having a predetermined weight is loaded on the lifting platform 107 and a load is applied to the rod 127, and the rod 127 held by the chuck portion 108 is rotated by driving the rotation drive source. In each predetermined depth unit, the number of rotations of the rod 127 required to penetrate the predetermined depth and the load applied at that time are measured.
[0003]
[Problems to be solved by the invention]
However, in this penetration test, a phenomenon that the rod penetrates into the ground only by a load, that is, a self-sink phenomenon occurs regardless of rotation. This is a phenomenon that occurs because the ground is soft. When this self-sink occurs, the drive of the rotary drive source is temporarily stopped, the load is changed as necessary, and whether the rod penetrates into the ground only with the load. It is necessary to observe. In general, the tip of the rod is attached with a screw point with a sharp tip that twists a quadrangular pyramid, and this is a spiral groove between the ridge lines in a cross section perpendicular to the ridge line of the corner by this twist. There is a so-called spiral groove in the shape. For this reason, if the geology is soft enough to cause self-settlement, the rod self-rotates due to the resistance of the soil acting on the screw point and can be penetrated only by the load. However, in such a penetration tester, the chuck portion and the rotation drive source are directly connected. Therefore, when the drive of the rotation drive source is stopped, the rod cannot be rotated at all due to the reduction ratio of the rotation drive source or the like. Even if it is in the geology that can be penetrated if the rod is self-rotating, the spiral groove of the screw point may be subjected to the resistance of the soil to stop the penetration. Therefore, although it is a stratum that naturally undergoes subsidence, it is mistakenly determined that the subsidence does not occur, and the risk of subsidence cannot be detected in advance. This is a major factor affecting earthquake resistance.
[0004]
In addition, in order to solve this problem, there is one that uses a one-way clutch that transmits the driving force of the rotational drive source only in one direction of rotation. After the penetration test, a large force is applied to the one-way clutch when separating from the threaded portion (not shown) that is the joint of the rod. I cannot add power. For this reason, workability | operativity in the cutting | disconnection work of a rod is bad. Further, when the one-way clutch is used, there is a problem that detailed data at the time of self-sinking cannot be obtained because it is impossible to measure the rotational torque of the rod itself at the time of self-sinking.
[0005]
An object of the present invention is to solve the above-mentioned problems and to provide an automatic penetration testing machine capable of penetrating a rod into the ground in a state close to a manual penetration test and knowing precise geological data in detail. .
[0006]
[Means for Solving the Problems]
An object of the present invention is to provide a lifting platform 7 that can be moved up and down along the column 3, a chuck portion 8 that holds a rod 27 is connected to the lifting platform and connected to a chuck rotation drive source so as to be rotatable. In the automatic penetration tester configured to penetrate the ground into the ground, a power transmission / cutting means for turning on and off the rotational force from the chuck rotation drive source is provided in the rotation transmission system 21 between the rod 27 and the chuck rotation drive source, A speed detection sensor 15 for detecting the descending speed of the elevator 7 is disposed on the elevator platform 7. On the other hand, when the speed detection sensor 15 receives a signal from the speed sensor 15, a control unit 9 that enters the power on / off means and gives a cut-off signal In addition, when the power on / off means receives a signal exceeding the preset lowering speed from the speed detection sensor 15, it determines that it is self-sinking, and at this time of self-sinking, the rotation of the chuck rotation drive source and the chuck part 8 is determined. An automatic penetration tester configured to release the transmission and place the rod 27 in the idling state, and otherwise maintain the rotation transmission between the chuck rotation drive source and the chuck portion 8 so that the rod 27 is connected. Is achieved by providing
[0008]
Further, the object is to provide a lifting platform 7 that can be moved up and down along the column 3, and a chuck portion 8 that holds a rod 27 is connected to the lifting platform 7 and connected to a chuck rotation drive source so as to be rotatable. In the automatic penetration tester configured to penetrate the ground 27 into the ground, a power transmission / cutting means for turning on and off the rotational force from the chuck rotation drive source is provided in the rotation transmission system 21 between the rod 27 and the chuck rotation drive source, A speed detection sensor 15 for detecting the descending speed of the elevator 7 is disposed on the lifting platform 7, while a reaction force detection sensor 40 for detecting a reaction force and a rotation torque of the rod 27 due to penetration into the rotation transmission system 21. And a torque detection sensor 41, which are combined with the speed detection sensor 15 as necessary, and upon receiving a necessary signal from these sensors, enters the power on / off means and transmits the signal. Also to provide an automatic penetration tester connected to the control unit 9 to give achieved.
[0009]
Moreover, when the power on / off means in this configuration receives signals indicating that the reference values set in advance from all or any one of the speed detection sensor 15, the reaction force detection sensor 40, and the torque detection sensor 41 are received. In this self-sink, the rotation transmission between the chuck rotation drive source and the chuck portion 8 is released and the rod 27 is idled. Otherwise, the rotation transmission between the chuck rotation drive source and the chuck portion 8 is transmitted. Keep the rod 27 What to connect It is.
[0010]
Moreover, the power on / off means is configured to connect the chuck rotation drive source and the chuck portion as necessary so that the rotational torque of the rod during self-sinking can be obtained. Is Thus, the rotational torque at the time of self-sink can be measured, and more detailed data can be obtained.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 3. 1 and 2, reference numeral 1 denotes an automatic penetration testing machine, which includes two bases 2 arranged in parallel, a column 3 erected perpendicularly thereto, and a load that can be moved up and down along the column 3. A stand unit 6 and a control unit 9 for controlling each drive part are provided. There are various types of penetration tests, such as standard penetration tests and Dutch cone penetration tests. The automatic penetration testing machine described in this embodiment is called a Swedish sounding test defined in JIS (Japanese Industrial Standards) A1221. Is. In this testing machine, the two bases 2 are connected to each other in the vicinity of the middle thereof, and the support column 3 is detachably installed on the connecting part. The support column 3 is formed with guide paths 4 on both side surfaces, and a guide chain 5 as a meshing member is disposed and fixed along the longitudinal direction of the support column 3 on the back surface thereof.
[0012]
The loading platform unit 6 includes a lifting platform 7 that can be moved up and down along the column 3, a chuck portion 8 that is attached to the lifting platform 7, and a lifting unit 10 that drives the lifting platform 7 up and down. The elevator 7 can be moved up and down along the column 3, and the elevator 7 is installed so as to surround the column 3. The lifting unit 10 is attached to the rear part of the lifting platform 7, and a position detection sensor (not shown) for detecting an upper limit position and a lower limit position associated with the lifting of the lifting platform 7 is mounted.
[0013]
The elevating unit 10 has a first motor 11 as an elevating drive source installed at the rear part of the elevating platform 7, and an output shaft (not shown) of the first motor 11 has a speed reducing mechanism (not shown). It is connected to the sprocket shaft 13 through a lifting transmission system 12 including a not-shown). Thereby, the rotation of the first motor 11 is transmitted to the sprocket shaft 13. The first motor 11 is provided with a lock mechanism (not shown) that can be driven in forward and reverse rotations and fixes the output shaft to be non-rotatable when stopped. Further, the sprocket shaft 13 is integrally attached with a lifting transmission sprocket 14 which is an example of a toothed rotating member formed with a plurality of teeth meshing with the guide chain 5 of the support column 3. A lift brake system (not shown) as a brake means capable of adjusting a brake resistance by changing a voltage is disposed in the lift transmission system 12 between the lift transmission sprocket 14 and the lift transmission sprocket 14. This causes a density change in the magnetic powder (not shown) enclosed in the inside due to a voltage load, and thereby the lifting transmission system with an accurate slip torque generated by the frictional action or meshing action of the powders. 12 is configured to add a brake resistance.
[0014]
The lift transmission system 12 includes a one-way clutch (not shown). The one-way clutch is connected only when the loading table unit 6 is lifted by driving the first motor 11, and the lift transmission sprocket. 14 is driven to rotate, and the one-way clutch is disengaged when the loading table unit 6 is lowered. Further, a speed detection sensor 15 as an example of speed detection means is provided at a position orthogonal to the tooth rotational movement surface of the lift transmission sprocket 14, and the teeth of the lift transmission sprocket 14 when the loading table unit 6 is lowered. The passage is detected as a pulse signal, the rotation of the lift transmission sprocket 14 is detected, and the descending speed of the loading platform unit 6 is detected.
[0015]
A second motor 20 serving as a chuck rotation drive source capable of forward / reverse rotation driving provided with a speed reduction mechanism (not shown) is disposed on the base 16 installed on the lifting platform 7 to which the chuck unit 8 is attached. In addition, a chuck portion 8 having an axis parallel to the axis thereof is connected to the second motor 20 via a rotation transmission system 21 and installed. This rotation transmission system 21 is connected to a main drive sprocket 23 that is attached to an output shaft (not shown) of the second motor 20 via a clutch portion 22 as a power on / off means for turning the rotation on and off, and to the lower end of the chuck portion 8. A driven sprocket 24 to be attached and an endless chain 25 for connecting the sprockets 23 and 24. The clutch portion 22 is configured so that the second motor 20 rotates a screw point 26, which will be described later, into the ground in a screwing and penetrating direction. At the time of driving, the output shaft of the second motor 20 and the main sprocket side are connected to rotate the output shaft and the main sprocket 23 integrally, and the rotation is transmitted to the chuck portion 8. The clutch portion 22 as the power on / off means is connected or released in either forward or reverse rotation, and is specifically a normal mesh clutch, centrifugal clutch, friction clutch, electromagnetic clutch or the like. It is connected or disconnected by a signal from the control unit 9 described later.
[0016]
The chuck portion 8 is rotatable with respect to the base 16, and a rod 27 is detachably inserted and held in the chuck portion 8 during a penetration test. The chuck portion 8 is configured to insert and hold a rod 27 having a predetermined length. An internal thread portion (not shown) is provided at one end of the rod 27 and an extension rod 27 is added to the other end. A certain male screw portion (not shown) is formed. The female thread portion is formed with a so-called spiral groove having a groove shape in a cross section in a direction perpendicular to the ridgeline of the twist and a groove shape over the entire length by right-twisting the pyramidal material. Screw points 26 that define the screwing direction are screwed together. On the other hand, the male threaded portion at the other end of the screw point 26 rotates an extension rod (not shown) having the same shape during the penetration test in the same direction as the screwing direction when the screw point 26 penetrates into the ground. The penetration test can be continued until the screw point 26 reaches a desired depth. Further, a loading arm 30 protruding forward is fixed to the base 16, and the weight 31 of the loading platform unit 6 is set to 1000 N in the loading arm 30 during the penetration test. Is loaded.
[0017]
Further, the control unit 9 controls the driving of the first motor 11 and the second motor 20 by signals of a speed detection sensor 15 and a position detection sensor (not shown) or by manual input key operation, and the speed detection sensor. 15 adjusts the voltage applied to the powder brake (not shown) of the lifting / lowering transmission system 12 by comparing the number of pulses per predetermined time detected by the reference number 15 with a preset reference pulse number. It is configured to adjust the resistance. On the other hand, the control unit 9 gives a control signal of the speed detection sensor 15 to the clutch unit 22 of the power on / off means, and the control signal can also be given to the clutch unit by manual operation. It has become. In addition, the control unit 9 is configured to process penetration test data such as the load applied to the rod 27, the number of rotations of the rod 27, and the amount of penetration of the rod 27. Note that the first motor 11 as the lifting drive source is driven by a transmission shaft (not shown) of the lifting transmission system 12 when the loading table unit is lowered during the normal penetration test in which no self-sink occurs by the control unit 9. The one-way clutch is controlled to idle at a speed faster than the rotation.
[0018]
When a penetration test is performed by the automatic penetration testing machine 1, first, the first motor 11 as a lifting drive source is driven forward to raise the loading table unit 6 along the column 3 to the upper limit position. When the loading table unit 6 reaches the upper limit position, the driving of the first motor 11 is temporarily stopped, and the lift transmission system 12 is immediately fixed by a lock mechanism (not shown). On the other hand, the lifting / lowering transmission sprocket 14 always receives the weight of the loading table unit 6 and tries to rotate in the direction in which the loading table unit 6 descends. However, since the lifting / lowering transmission system 12 is in a fixed state, the loading table unit 6 is in the upper limit position. At rest.
[0019]
In this state, the rod 27 is attached to the chuck portion 8 of the loading table unit 6 and a weight 31 having a total weight of 1000 N of the loading table unit 6 is loaded on the loading arm 30. After this, as shown in FIG. 3, when the start signal is input, the first motor 11 is driven (hereinafter referred to as reverse driving) in reverse to the driving when the loading table unit is raised. The stopped sprocket shaft 13 becomes rotatable, whereby the loading platform unit 6 starts to descend and positions the tip of the screw point 26 near the ground surface. In order to stop the lowering of the loading table unit 6, it is only necessary to stop the driving of the first motor 11 as described above.
[0020]
After positioning the screw point 26 in this way, the voltage applied to the powder brake is adjusted, and a brake resistance is appropriately added. In this state, when the first motor 11 is reversely driven again to lower the loading table unit 6 as described above, the screw point 26 receives the weight of the loading table unit 6 and is pressed into the ground. Thereafter, the first motor 11 continues reverse driving until the extension rod (not shown) is added, causing the one-way clutch of the lift transmission system 12 to idle. In the present embodiment, the loading table unit 6 is lowered only by its weight during normal penetration, so that an accurate load is applied to the rod 27. Further, when the loading table unit 6 is lowered without attaching the rod 27 to the chuck portion 8, there is no penetration resistance acting on the rod 27, so the loading table unit 6 tends to fall freely. However, the loading table unit 6 is lowered by the reverse drive of the first motor 11 by the action of the one-way clutch of the lifting transmission system 12, which is safe.
[0021]
At the start of penetration, rotation of the lifting transmission sprocket 14 is suppressed by the brake resistance of the powder brake of the lifting transmission system 12. The brake resistance at this time is such that the weight of the loading table unit 6 acting on the rod 27 is 500 N, and the rod 27 penetrates into the ground in the same state as when a load of 500 N is applied. When the rod 27 does not penetrate in this load state, the loading table unit 6 stops, and accordingly, no pulse is detected from the speed detection sensor 15. In response to this, the voltage of the powder brake is adjusted, the brake resistance is reduced, and the same state as when the load of 750 N is applied to the rod 27 is created. Further, when the sinking of the rod 27 stops under this load, the voltage load of the powder brake is finally stopped, and a load of 1000 N, which is the original weight of the loading platform unit 6, is applied to the rod 27.
[0022]
In this way, the self-sinking measurement control is performed, and when the self-sinking determination in the control unit 9 is repeated and the sinking of the rod 27 is stopped even with a load of 1000 N, it is determined that the self-sinking is completed by the signal from the speed detection sensor 15 Subsequently, the rod starts rotating, and the power on / off means acts to connect the clutch portion 22. Then, the second motor 20 drives the rod 27 to rotate in the screwing direction of the screw point 26, rotates with the rod 27 loaded with a load of 1000 N, and penetrates the rod 27 into the ground (hereinafter referred to as rotational penetration). Rotational penetration measurement is performed. During this rotation penetration, the load is maintained at 1000 N unless self-sink occurs. Self-sinking is a phenomenon that occurs when the screw point 26 reaches a soft formation. The load applied to the rod 27 is too heavy, so the rod 27 settles quickly regardless of rotation. This is a phenomenon in which the rod 27 penetrates.
[0023]
On the other hand, when the self-sink occurs, the descending speed of the loading platform unit 6 rapidly increases as the rod 27 sinks, so that the rotational speed of the lift transmission sprocket 14 increases and the pulses per predetermined time detected by the speed detection sensor 15. The number increases. The number of pulses per predetermined time is constantly monitored by the control unit 9 during the penetration test, and when the number of pulses exceeding the reference pulse number set in advance in the control unit 9 is detected, self-sink occurs, and the second motor The driving of 20 stops. In this state, the self-sinking measurement of 1000 N is performed, and when the descending speed becomes faster, the voltage of the powder brake is adjusted, the load acting on the rod 27 is unloaded step by step, and the self-sinking intrusion measurement state is obtained. When this penetration speed slows down, the load is increased in steps until the load reaches 1000 N as in the first stage of the penetration test described above, and the self-sedimentation measurement state continues.When the reference pulse number is reached, rod rotation starts again. Then, the second motor 20 is driven to rotate the rod 27. When the number of pulses exceeding the reference number of pulses is detected, the clutch portion 22 which is a power on / off means is released by this signal, and the rod 27 is in an idling state. On the contrary, when the self-sinking measurement state is finished, the clutch portion 22 is connected, and the rod 27 is in a rotational penetration state.
[0024]
During this self-sinking, that is, in a state where the driving of the second motor 20 is stopped, the resistance of the soil acts on the spiral groove of the screw point 26, and a rotational force is applied to the screw point 26. This rotational force is transmitted to the chuck portion 8 through the rod 27 and further transmitted to the main sprocket 23 through the driven sprocket 24 and the endless chain 25. The rotation direction at this time is to rotate the main sprocket 23 in the winding direction of the spiral groove of the screw point 26, that is, the screwing direction of the screw point 26, but the clutch portion 22 has already been released and the rod 27 is in the idling state. Therefore, the rod 27 rotates in a state very close to manual penetration only by the resistance of the soil acting on the screw point 26 without receiving the resistance of the second motor 20.
[0025]
When the loading platform unit 6 reaches the lower limit position during the penetration test, the driving of the first motor 11 and the second motor 20 is stopped. At this time, when the penetration test is continued, the extension rod 27 is added to the rod 27. After the extension rod 27 is added, the penetration test is continued while repeating the extension rod 27 until the predetermined set depth is reached. When the desired depth or hardness is reached, the penetration is completed and the penetration measurement is completed.
[0026]
Further, in this embodiment, the presence or absence of self-sink is determined only by the speed detection sensor 15, but in addition to this, as shown in FIG. A reaction force detection sensor 40 for detecting a reaction force received by the rod when penetrating into the inside and a rotation transmission system 21 are arranged in contact with each other, and each of the torques set in advance by detecting the rotation resistance of the rod 27 is detected. The torque detection sensor 41 for determining whether or not the reference value is smaller than the reference value can be used in combination as necessary, and more detailed data can be obtained in this way. Furthermore, by using the reaction force detection sensor 40 and the torque detection sensor 41 alone, necessary data for the purpose can be obtained.
[0027]
In the above embodiment, even when the rod 27 is connected to the chuck motor 8 while maintaining the rotation transmission between the second motor 20 of the chuck rotation drive source and the chuck unit 8, the control unit 9 The rod 27 can be idled by giving a signal to turn on and off the clutch portion 22 as necessary. Conversely, when it is necessary to measure the rotational torque of the rod 27 during self-sinking, The data can be easily obtained by giving a signal to the clutch portion 22 and connecting it for a required time.
[0028]
【The invention's effect】
As is clear from the above-described embodiment, the present invention allows the lifting platform 7 having a predetermined weight to be lifted and lowered, and the chuck portion 8 holding the rod 27 to be connected to a chuck rotation drive source to be rotatable, An automatic penetration tester that applies rotational force and weight to the rod 27 and penetrates into the ground, and includes a power on / off means for turning the rotational force into the rotation transmission system 21 between the rod 27 and the chuck rotation drive source. The speed detecting sensor 15 for detecting the descending speed of the elevator 7 is disposed on the lifting platform 7, and the control unit 9 that enters the power on / off means and gives a signal to the speed detecting sensor 15 is connected to the speed detecting sensor 15. When a signal exceeding the lowering speed is received, it is determined that the self-sink is generated, the rotational drive is canceled and the rod 27 is idled, otherwise the chuck rotation drive source is used as necessary. An automatic penetration tester to the rod 27 in the connected state.
[0029]
For this reason, in the penetration test, it is not necessary for the operator to constantly observe whether or not the rod penetrates into the ground only by changing the load. In addition, the chuck part and the chuck rotation drive source are not always connected, and when the self-sinking occurs, the power turning-on means works and this connection is completely released, so the rod self-rotates due to the resistance of the soil acting on the spiral groove. However, it can penetrate only by load. As a result, it can be accurately determined that the self-sinking layer is a soft layer, so it is possible to detect the risk of subsidence in advance and cope with unequal subsidence and earthquake resistance of buildings. become.
[0030]
Further, in this automatic penetration testing machine, in addition to the speed detection sensor 15, the rotation transmission system 21 is provided with a reaction force detection sensor 40 and a torque detection sensor 41 for detecting a reaction force and a rotation torque of the rod 27, and these sensors are provided. Detailed data at the time of self-sinking can be obtained by combining with a speed detection sensor as needed or using it alone to receive a necessary signal.
[0031]
Further, since the forward / reverse rotation of the rod 27 is connected or released by the power on / off means in the above-described configuration, when the rod that has been added and lengthened after the penetration test is disconnected, by connecting the clutch portion, Workability is improved. In addition, since the forward and reverse idling is possible during the release of the clutch part, the screw point at the end of the rod bites into gravel in the ground during the penetration work, and the rod can no longer rotate. If there is, if the rotational driving force of the rod is removed, the reverse rotation is generated by the reaction force in the torsional direction stored in the rod. The drive source is not damaged. In addition, if a torque detection sensor is provided in the rotation transmission system between the rod and the clutch part, and the clutch part is connected for a required time during self-sinking, the rotational torque of the rod itself during self-sinking can be easily measured, There are specific effects such as obtaining detailed data.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view of a main part of an automatic penetration testing machine according to the present invention.
FIG. 2 is a side view of an automatic penetration testing machine according to the present invention.
FIG. 3 is a flowchart showing the operation of the automatic penetration testing machine according to the present invention.
FIG. 4 is an explanatory view of a conventional automatic penetration testing machine.
[Explanation of symbols]
1 Automatic penetration testing machine
2 base
3 props
4 guideway
5 Guide chain
6 Loading platform unit
7 Lift platform
8 Chuck part
9 Control unit
10 Lifting unit
11 First motor
12 Lifting transmission system
13 Sprocket shaft
14 Lifting transmission sprocket
15 Speed detection sensor
16 base
20 Second motor
21 Rotation transmission system
22 Clutch part
23 main sprocket
24 driven sprocket
25 Endless chain
26 Screw points
27 Rod
30 Loading arm
31 spindles
40 Thrust detection sensor
41 Torque detection sensor

Claims (4)

A lifting platform (7) that can be moved up and down along the column (3) is provided, and a chuck portion (8) that holds the rod (27) is connected to the chuck rotation drive source so as to be rotatable. In an automatic penetration testing machine configured to penetrate the rod into the ground,
A speed detecting sensor for providing power on / off means for turning on and off the rotational force from the chuck rotating drive source in the rotation transmission system (21) between the rod and the chuck rotating drive source, and detecting the descending speed of the lifting platform. (15) is arranged, and on the other hand, when a speed signal is received by the speed detection sensor, a control unit (9) for entering the power on / off means and giving a signal is connected, and the power on / off means is connected to the speed detection sensor. If a signal exceeding the preset lowering speed is input, it is determined that self-sinking occurs. When this self-sinking occurs, the rotation transmission between the chuck rotation drive source and the chuck part is released and the rod is idled. An automatic penetration testing machine characterized in that it is configured to maintain the transmission of rotation between the drive source and the chuck part and to connect the rods . An automatic penetration test with a configuration in which a lifting platform that can be moved up and down along the support column is installed, a chuck part that holds the rod is connected to a driving source for rotating the chuck, and the rod is inserted into the ground. In the machine
The rotation transmission system between the rod and the chuck rotation drive source is provided with power on / off means for turning on and off the rotational force from the chuck rotation drive source, and a speed detection sensor for detecting the lowering speed of the lift is arranged on the lifting platform. On the other hand, a reaction force detection sensor (40) and a torque detection sensor (41) for detecting the reaction force and rotational torque of the rod due to penetration into the ground are provided in the rotation transmission system, and these sensors are provided with the speed as required. An automatic penetration testing machine, which is combined with a detection sensor and connected to a control unit which enters the power on / off means and gives a signal when receiving a necessary signal from these sensors. When the power on / off means receives a signal indicating that a preset reference value has been reached from all or any one of the speed detection sensor, reaction force detection sensor, and torque detection sensor, it determines that it is self-sinking. the rod idles sometimes releases the transmission of rotation between the chuck rotary drive source and the chuck portion, to the connecting state rod to maintain the transmission of rotation between the chuck rotation driving source and the chuck portion in other cases The automatic penetration testing machine according to claim 2, wherein 4. The automatic penetration tester according to claim 2, wherein the power on / off means is configured to connect the chuck rotation driving source and the chuck portion as necessary so as to obtain the rotational torque of the rod during self-sinking. .

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