JP2021014707A - sampler - Google Patents

Abstract

To provide a sampler which suppresses co-rotation of an inner tube by assigning an anti-corotation function and an expansion function that a single mechanism in a conventional outer head has been in charge to separate mechanisms, and which can improve the quality of a collected sample.SOLUTION: A sampler 1 includes: an outer head 10; a slide unit 20 connected to a tip side of the outer head 10 in a rotatable manner via a first bearing 21a; an inner head 30 connected to a tip side of the slide unit 20; an outer tube 40 connected to the tip side of the outer head 10; and an inner tube 50 connected to a tip side of the inner head 30. The slide unit 20 includes a shaft guide 21, a slide shaft 22 and a spring 23. An anti-corotation function and an expansion function of the inner tube 50 with respect to the outer head 10 is assigned to the first bearing 21a and the slide unit 20.SELECTED DRAWING: Figure 1

Description

The present invention relates to a sampler, and in particular, by sharing the rotation prevention function and the expansion / contraction function, which were conventionally carried out by a single mechanism in the outer head, with separate mechanisms, the rotation of the inner pipe is suppressed and the quality of the collected sample is improved. Regarding samplers to improve.

In structural design such as infrastructure development, new construction of building structures, and seismic examination of various facilities, specifications and costs are determined by the mechanical design values of the ground. The mechanical design values are the shear strength constant when examining the fracture phenomenon of the ground itself and the frictional force with different materials, and the deformation coefficient when estimating the amount of fluctuation of the ground. Infrastructure and buildings It will be a major deciding factor such as the detailed specifications of the above and the existence of ground countermeasure construction method.
The design value is set from the result of the indoor soil test using the sample (sample) collected from the field board. Therefore, sampling and indoor soil testing are crucial factors that have a direct impact on the safety and cost of the structure.
Of these, for indoor soil tests, practical standards and standards are generally in place, so the error area is relatively small and a certain level of reliability is ensured.
On the other hand, in sampling, the quality of the sample is often deteriorated due to the influence of disturbance at the time of sampling. Especially in sandy ground, turbulence is likely to occur due to the tightness of sand and the influence of the mixing ratio of fine particles such as clay.
Therefore, how to reduce the influence of turbulence and improve the quality of the sample is one of the issues in the technical field of sampling.

Conventional techniques for sampling for indoor soil tests include, for example, a fixed piston type thin wall sampler, a Denison sampler, and a triple tube sampler. Patent Documents 1 and 2 disclose a triple tube sampler type sampler. The Denison sampler and triple tube sampler are an outer head that can rotate with a boring rod, an outer tube that connects to the outer head, a spindle that is placed inside the casing of the outer head, a spring that urges the spindle, and an inner head that connects to the tip of the spindle. The triple tube sampler further comprises a liner inside the inner tube, which comprises an inner tube, which connects to the tip of the inner head. The middle portion of the spindle expands to the outer peripheral side, and the expanded diameter portion is sandwiched between thrust type bearings from above and below to rotatably hold the spindle in the casing (FIG. 5).

In Denison samplers and triple tube samplers, the inner tube is cut off from the rotation of the outer tube via a spindle that is rotatably housed in the casing. Therefore, while the ground is rotationally cut with the bit of the outer pipe, the inner pipe is pushed into the ground without rotating, and a sample can be collected inside the inner pipe or the liner. Further, the spindle is urged toward the tip by a spring in the casing, and the impact received by the inner pipe from the ground can be absorbed by the expansion and contraction of the spindle.
These samplers have a structure in which the spindle in the casing is rotationally held by a bearing to perform a rotational function, and is urged by a spring to also perform an expansion / contraction function.

JP-A-2018-91124 JP-A-2007-239358

"Geotechnical Investigation Method and Explanation (JGS1223-2012 Rotary Triple Tube Sampler Soil Sample Collection Method)" Published by the Japanese Geotechnical Society, March 25, 2013

The prior art has the following problems.
<1> During rotary cutting of the ground, when the compression-deformed spring interferes with the outer circumference of the spindle, the rotation of the outer pipe is transmitted to the inner pipe via the spindle, and the inner pipe rotates with the outer pipe. Due to the rotation, the peripheral surface of the sample being collected is rubbed against the inner surface of the inner tube and is worn or partially damaged, so that the quality of the sample is significantly deteriorated.
<2> When the inner pipe rotates, the soil between the sample in the shoe and the shoe is disturbed, and the disturbed soil bites between the inner surface of the shoe and the soil in a wedge shape. This increases the frictional resistance between the shoe and the soil, preventing the sample from entering the tube (core clogging). Whenever a core is clogged, it is necessary to pull up the sampler to disassemble the inner tube, clear the clog, and then recollect. This requires a great deal of effort and time. Therefore, the burden on the worker is heavy, and the construction period may be delayed. Further, since the sample in a certain section is collected in a divided state, there is a possibility that the required length according to the test purpose cannot be secured.
<3> Since the spindle has a structure that doubles as a rotating shaft and a sliding shaft, friction in two directions of rotation and sliding occurs between the spindle and the bearing portion that supports the spindle. Therefore, the oil seal of the bearing portion is easily worn, and muddy water or the like is likely to enter the casing. Further, the peripheral surface of the spindle is cut into a groove shape by interfering with the outer circumference of the spindle while the spring rotates. Therefore, the spindle wears quickly and the replacement life is short.
<4> Since the casing has a structure integrated with the outer head, the inner surface of the outer pipe and the surface of the casing rotate synchronously. Therefore, the excavated water injected into the outer pipe flows relatively gently outside the casing, and at the same time enters the retention space in front of the casing from the outside of the casing, and at the same time, the casing, the outer pipe (rotating system), and the inner head (rotating system). It is vigorously agitated by the relative rotation of the non-rotating system). For this reason, a part of the excavated water that should originally pass between the outer pipe and the inner pipe and be discharged to the outside from the tip side of the outer pipe is agitated in the retention space behind the inner head, and a high water pressure is generated. .. Due to this water pressure, a part of the excavated water enters the casing from the oil seal portion along the spindle (FIG. 5). As a result, excavated water also infiltrates the bearings in the casing, which significantly reduces the function.
<5> Since the large casing rotates integrally with the outer head, there is a risk that the sample will be disturbed or damaged due to large blurring and vibration during rotary cutting.

An object of the present invention is to provide a sampler capable of solving the above-mentioned problems of the prior art.

The sampler of the present invention is a slide unit having an outer head that can be coupled to the tip of a boring rod and a first bearing, and is rotatably coupled to the tip side of the outer head with respect to a long axis via the first bearing. The slide unit, the inner head coupled to the tip side of the slide unit, the inner tube coupled to the tip side of the inner head, and the outer tube coupled to the tip side of the outer head, which are the slide unit, the inner head, and The slide unit includes a shaft guide having a sliding space inside and a shaft guide having a sliding space inside, and a slide unit having a rear end located in the sliding space and a tip on the tip side of the shaft guide. It is characterized by having a slide shaft protruding into the sliding space and a spring which is located in the sliding space and is ring-mounted on the slide shaft to elastically bias the slide shaft toward the tip side with respect to the shaft guide.
According to this configuration, it is possible to suppress the rotation of the inner tube, improve the quality of the collected sample, and prevent core clogging.

In the sampler of the present invention, the outer head has a head shaft protruding at the tip, the first bearing is located at the rear end of the shaft guide, and the outer circumference of the head shaft is rotatably held, and the head shaft and the first bearing are held. There may be an oil seal space between the bearings that can seal the lubricant.
According to this configuration, by adopting a cap structure in which the first bearing covers the head shaft from the tip side, it is possible to prevent the head shaft from interfering with other non-rotating members, and the rotating members and the non-rotating system. It is possible to ensure the edge cutting with the member of. Further, by forming the first bearing with an oil-sealed space, it is possible to prevent deterioration of the rotational function due to the ingress of muddy water or the like.

In the sampler of the present invention, the first bearing may have a radial ball bearing or a radial roller bearing that can be ringed on the head shaft.
According to this configuration, by applying a radial bearing having high rotational performance, it is possible to reduce blurring and rotational defects during rotation. Further, since the replacement life of the bearing is longer than that of the thrust bearing of the prior art, the maintenance cost can be reduced.

In the sampler of the present invention, the inner head has a second bearing, and the inner head may be rotatably coupled to the tip end side of the slide shaft with respect to the long axis via the second bearing.
According to this configuration, even if a temporary failure occurs in the first bearing and the rotation occurs during the rotation operation of the sampler, the second bearing works immediately and the fail-safe function is exhibited. Can be done.

In the sampler of the present invention, the second bearing is located at the rear end of the inner head, holds the outer circumference of the slide shaft rotatably, and is an oil seal capable of sealing a lubricant between the slide shaft and the second bearing. It may have a space.
According to this configuration, by adopting a cap structure in which the second bearing covers the slide shaft from the tip side, it is possible to prevent deterioration of the rotational function due to infiltration of muddy water or the like.

The sampler of the present invention may include a tubular liner that can be accommodated inside the inner tube.
By sharing the pushing function and the accommodating function between the inner tube and the liner, it is possible to suppress the disorder of the sample and improve the quality of the sample.

From the above configuration, the sampler of the present invention has at least one of the following effects.
<1> By sharing the rotation prevention function and expansion / contraction function, which were conventionally performed by a single spindle, with the first bearing and the slide shaft, it is possible to prevent the rotation from occurring due to the spring interfering with the rotating shaft. Can be done. As a result, it is possible to suppress the occurrence of wear and damage of the sample and the occurrence of core clogging due to the rotation, and improve the quality of the sample.
<2> By suppressing the occurrence of core clogging, it is possible to reduce the work load due to recollection of the sample and improve the work efficiency of sampling.
<3> Since rotation is not applied to the slide shaft, friction related to rotation does not occur between the slide shaft and the shaft guide. Therefore, the slide shaft wears less and the replacement life is longer than that of the conventional spindle. Further, since the oil seal of the shaft guide is not easily worn, the casing can maintain high watertightness.
<4> Since the outer head and the slide unit rotate relatively, the excavated water is largely agitated in the vicinity of this joint, while is hardly agitated in the vicinity of the joint between the slide shaft and the inner head. Therefore, although the water pressure of the excavated water temporarily increases in the space in front of the water passage due to agitation, the water pressure is dispersed while passing through the flow path space outside the slide unit, and passes through the joint portion between the slide unit and the inner head. , It is discharged straight to the outside through the gap between the outer pipe and the inner pipe. Therefore, since the excavated water does not stay behind the inner head, it is possible to prevent the excavated water from entering the accommodation space due to the increase in water pressure.
<5> Since the edge of rotation is cut at the joint between the outer head and the slide unit, the member inside the outer pipe does not rotate during rotary cutting. Therefore, there is little blurring and vibration during rotary cutting, and there is little risk of disturbance or damage to the sample.

Explanatory drawing of the sampler of this invention. Explanatory drawing of the slide unit. Comparative photograph (1) of the wear state of the slide shaft. A comparative photograph (2) of the wear state of the slide shaft. Explanatory drawing of the prior art.

Hereinafter, the sampler of the present invention will be described in detail with reference to the drawings.
In the present invention, the "front" and "tip" mean the right side in FIG. 1, that is, the outer pipe side, and the "rear" and "rear end" mean the left side, that is, the outer head side in FIG. In addition, terms such as "upper" and "lower" mean each direction in a state where the outer head is fixed to the tip of the boring rod and the tip is directed to the ground.
Further, the "rotating system" means a member designed to rotate with respect to the ground during operation. "Non-rotating system" means a member designed not to rotate with respect to the ground during operation.

<1> Overall configuration (Fig. 1).
The sampler 1 of the present invention includes an outer head 10, a slide unit 20 coupled to the tip side of the outer head 10, an inner head 30 coupled to the tip side of the slide unit 20, and an inner head 30 coupled to the tip side of the inner head 30. It includes at least a tube 50 and an outer tube 40 coupled to the tip end side of the outer head 10.
The slide unit 20 is rotatably configured with respect to the long axis of the outer head 10 via the first bearing 21a. Further, in this example, the inner head 30 is rotatably configured with respect to the long axis of the slide unit 20 via the second bearing 31.
At least a part of the slide unit 20, the inner head 30, and the inner pipe 50 is housed inside the outer pipe 40.
In this example, a triple tube type structure in which the liner 60 is arranged inside the inner tube 50 will be described. However, the present invention is not limited to this, and a double-tube structure without the liner 60 may be used.

<1.1> Rotating system / non-rotating system.
The outer head 10 and the outer pipe 40 are members of a rotating system that rotate together with the boring rod during operation.
The slide unit 20, the inner head 30, the inner pipe 50, and the liner 60 are non-rotating members that do not rotate during operation.
The rotating member and the non-rotating member have a rotating edge cut at a joint portion between the outer head 10 and the slide unit 20. For this reason, most of the members in the outer pipe 40 do not rotate during operation, so that blurring and vibration caused by operation are small.

<2> Outer head.
The outer head 10 is a component that is coupled to the tip of the boring rod.
An outer tube 40 is ringed on the tip end side of the outer head 10, and the rotation of the boring rod is transmitted to the outer tube 40 via the outer head 10.
The outer head 10 has at least a head shaft 11 that connects to the slide unit 20, a connecting portion 12 that connects to the boring rod, and a running water channel 13 that discharges excavated water from the boring rod into the outer pipe 40.
The head shaft 11 projects from the center of the tip portion of the outer head 10 toward the tip end side, and is rotatably coupled to the first bearing 21a of the slide unit 20.
The connecting portion 12 is an insertion hole for the boring rod and is recessed from the center of the rear end portion of the outer head 10 toward the tip end side.
The flow channel 13 communicates from the inside of the connecting portion 12 to the flow path space S in front of the outer head 10. The number of running water channels 13 is not limited.

<3> Slide unit (Fig. 2).
The slide unit 20 is a component that shares the expansion / contraction function of the inner pipe 50 with respect to the outer head 10.
The slide unit 20 has a shaft guide 21 whose rear end is rotatably coupled to the head shaft 11 via a first bearing 21a, and an inner head 30 whose rear end is located inside the shaft guide 21 and whose tip is outside the shaft guide 21. A slide shaft 22 to be coupled and a spring 23 for elastically urging the slide shaft 22 with respect to the shaft guide 21 are provided.
By expanding and contracting the spring 23, it is possible to absorb the impact applied to the inner pipe 50 during rotary cutting of the ground.

<3.1> Shaft guide (Fig. 2).
The shaft guide 21 is a component that slidably holds the slide shaft 22.
The shaft guide 21 has a first bearing 21a, a rear guide 21b, a front guide 21c, a casing 21d, an accommodation space 21e, and an oil seal 21f.
The first bearing 21a is a member that is rotatably coupled to the head shaft 11.
The rear guide 21b is a cylindrical member that guides the sliding of the inner shaft 22a of the slide shaft 22 described later.
The front guide 21c is a cylindrical member that guides the sliding of the outer shaft 22c of the slide shaft 22.
The casing 21d is a cylindrical member that covers the rear guides 21b and the front guides 21c arranged side by side in the front-rear direction from the outside.
The accommodation space 21e is a space for accommodating the slide shaft 22 and the spring 23 inside, and is defined by the first bearing 21a, the rear guide 21b, the front guide 21c, and the casing 21d.
The oil seal 21f is a seal member for maintaining the watertightness of the accommodation space 21e, and is provided around the inner peripheral surface of the front guide 21c.

<3.2> Slide shaft (Fig. 2).
The slide shaft 22 is a component that is slidably held in the shaft guide 21.
The slide shaft 22 is a single shaft body as a whole, and includes an inner shaft 22a arranged in the accommodation space 21e, an outer shaft 22c whose tip is coupled to the inner head 30, and a stopper 22b located between the two. Have.
The inner shaft 22a has a diameter smaller than the inner diameter of the spring 23 and is inserted into the inner space of the spring 23. The rear end of the inner shaft 22a is guided by the rear guide 21b.
The outer shaft 22c is inserted into the front guide 21c, and the tip of the outer shaft 22c protrudes toward the tip of the front guide 21c.
The stopper 22b is arranged in the accommodation space 21e, the back surface of the stopper 22b abuts on the tip of the spring 23, and the front surface of the stopper 22b faces the back surface of the front guide 21c. The stopper 22b is urged in the accommodation space 21e toward the tip by the spring 23.

<3.3> First bearing.
The first bearing 21a is a component that shares the function of preventing rotation of the inner pipe 50 with respect to the outer head 10.
The first bearing 21a is recessed in the rear end of the shaft guide 21.
A head shaft 11 is housed inside the first bearing 21a and is rotatably held.
The sampler 1 of the present invention employs a cap structure in which the first bearing 21a covers the head shaft 11 from the tip side. Therefore, the head shaft 11 is less likely to interfere with other non-rotating members during rotary cutting of the outer tube 40, and it is possible to prevent the inner tube 50 from rotating due to the transmission of rotation.
In this example, as the first bearing 21a, a bearing mechanism that can be fitted to the head shaft 11 from the tip side is adopted, and a plurality of radial ball bearings interposed between the inner surface of the first bearing 21a and the outer circumference of the head shaft 11 The slide unit 20 and the outer head 10 are rotatably connected via the above. In addition, the bearing may be a radial roller bearing.
An oil seal space in which the lubricant can be sealed may be formed between the first bearing 21a and the head shaft 11. In this case, for example, the grease nipple is communicated from the inside of the first bearing 21a into the accommodation space 21e, and the lubricant is injected into the first bearing 21a from here.
In the case of this example, by forming the first bearing 21a with a sealed structure of the lubricant, it is possible to prevent excavation water or the like from entering the first bearing 21a and prevent deterioration of the rotational function.

<3.3.1> Types of bearings.
There are two types of bearings: radial bearings (radial ball bearings, radial roller bearings) that mainly support forces in the direction perpendicular to the axis, and thrust bearings (thrust ball bearings, thrust roller bearings) that mainly support forces in the axial direction. There is.
The radial bearing is a bearing in which a ball or a roller is held between an outer ring and an inner ring, and has features such as high rotational performance, high allowable rotational speed, less blurring, and low wear torque.
On the other hand, a thrust bearing is a bearing in which balls and rollers are held between upper and lower washer-shaped track discs, and has relatively low rotational performance, low allowable rotational speed, relatively large amount of blurring, and functional retention. Requires frequent replacement of lubricants.
The sampler of the prior art has a structure in which the spindle serves as both a rotating shaft and a sliding shaft, that is, the spindle rotates while supporting an axial axial load due to sliding, so a thrust bearing having low rotational performance must be applied. Because of the structure, it was not possible to apply a radial bearing.
On the other hand, in the sampler 1 of the present invention, since the first bearing 21a mainly needs to consider only the radial load in the direction perpendicular to the head shaft 11 axis, a radial bearing having high rotational performance can be applied. As a result, the first bearing 21a can exhibit high rotational performance and excellent maintainability.

<4> Inner head.
The inner head 30 is a component that connects the inner pipe 50 to the tip of the slide unit 20.
The rear end of the inner head 30 is coupled to the tip of the outer shaft 22c, and the inner tube 50 is ringed at the tip.
The inner head 30 has a check valve 32 that prevents the sample from falling out of the liner 60. As the check valve 32, for example, a combination of a ball and a spring arranged in a ventilation hole communicating with the inner head 30 can be adopted.
In this example, the second bearing 31 is recessed in the rear end portion of the inner head 30, and the inner head 30 and the outer shaft 22c are rotatably coupled via the second bearing 31.

<4.1> Second bearing.
The second bearing 31 is a component having a fail-safe function with respect to the rotation of the first bearing 21a.
The configuration of the second bearing 31 is the same as that of the first bearing 21a.
By providing the inner head 30 with the second bearing 31, the sampler 1 has a double rotation structure of the first bearing 21a and the second bearing 31.
In this case, when the outer head 10 is rotated, the edge between the outer head 10 located at the upper part and the slide unit 20 is cut first, the first bearing 21a is rotated preferentially, and the second bearing 31 is in normal operation. Does not work.
On the other hand, if a temporary defect occurs in the first bearing 21a during the rotation operation of the sampler 1 and the slide unit 20 rotates, the second bearing 31 immediately causes the rotation edge of the slide unit 20 and the inner head 30. By cutting, it is possible to prevent the inner tube 50 from rotating and prevent damage to the sample.
The second bearing 31 is not an essential component. That is, the slide shaft 22 and the inner head 30 may be non-rotatably coupled.

<5> Outer pipe.
The outer pipe 40 is a component that rotationally cuts the ground.
The outer pipe 40 is composed of a cylindrical member that houses at least a part of the slide unit 20, the inner head 30, and the inner pipe 50 inside.
The outer tube 40 is ringed on the tip end side of the outer head 10.
A crown 41 for cutting the ground is provided at the end edge of the outer pipe 40 on the tip end side.
Inside the outer pipe 40, a flow path space S through which excavated water flows is formed.

<6> Inner pipe.
The inner tube 50 is a component that is press-fitted into the ground to introduce the sample into the liner 60.
The inner tube 50 is made of a cylindrical member having an outer diameter smaller than the inner diameter of the outer tube 40.
The inner tube 50 is ringed on the tip end side of the inner head 30.
A shoe 51, which is a reduced diameter portion for press-fitting into the ground, is provided at the end edge of the inner pipe 50 on the tip end side.

<7> Liner.
The liner 60 is a component for collecting a sample inside.
The liner 60 is made of a tubular body having an outer diameter corresponding to the inner diameter of the inner pipe 50. The liner 60 is detachably arranged inside the inner pipe 50.
In this example, a tube made of acrylic resin is used as the liner 60.
By making the liner 60 independent of the inner tube 50, it is possible to prevent deformation and damage of the sample due to press fitting of the inner tube 50.
The liner 60 is not an indispensable component, and a double tube type configuration (Denison sampler) in which the liner 60 and the inner tube 50 are taken and replaced with a stainless steel thin wall liner may be used. In this case, the sample is collected in the tube of the thin wall liner.

<8> Comparison of usage conditions of slide shafts.
The usage states of the sampler 1 (Example 1) of the present invention and the sampler (Comparative Examples 1 and 2) of the prior art are compared.
Example 1: Two years from the start of use Total 82 bottles (41 bottles / year)
Comparative example 1: 2 years from the start of use Total use of about 45 (22.5 / year)
Comparative example 2: 2 years from the start of use Total use of about 30 (15 / year)
(1) Overall State FIG. 3 shows the usage states of the slide shaft 22 of Example 1 and the spindles of Comparative Examples 1 and 2. The inner shaft 22a (spindle rear end side) side is directed to the left side of the photograph, and the outer shaft 22c (spindle tip side) side is directed to the photo right side.
(2) State of Inner Shaft and Outer Shaft FIG. 4 shows a state of use of the inner shaft 22a (spindle rear end side) and the outer shaft 22c (spindle tip side) in the slide shaft 22 (spindle).
The comparison results are shown below.
(3) Discussion In Comparative Examples 1 and 2, many streaky grooves in the circumferential direction were observed on the surface on the rear end side of the spindle.
This indicates that when the spindle serves as both a rotating shaft and a sliding shaft, the compressed spring deforms and interferes with the peripheral surface of the spindle when the sampler is rotationally press-fitted. In addition, it is presumed that the inner pipe was rotated due to the interference of the spring.
On the other hand, in Example 1, no streaky grooves were found on the surface of the slide shaft 22.
This is because the slide shaft 22 only slides back and forth and does not rotate, so that friction in the circumferential direction due to the inner surface of the front guide 21c and the spring 23 does not occur. From this, it is inferred that the rotation of the inner pipe is effectively suppressed.
Further, the slide shaft 22 of the first embodiment is used more frequently than the spindles of the first and second comparative examples (about 1.8 times and about 2.7 times), but does not cause friction in the circumferential direction due to rotation. , The degree of wear is much lower than that of the spindles of Comparative Examples 1 and 2.
From the above, it is presumed that the sampler 1 of the present invention has a longer replacement life of the slide shaft 22 than that of the prior art.

1 Sampler 10 Outer head 11 Head shaft 12 Connection part 13 Water passage 20 Slide unit 21 Shaft guide 21a First bearing 21b Rear guide 21c Front guide 21d Casing 21e Storage space 21f Oil seal 22 Slide shaft 22a Inner shaft 22b Stopper 22c Outer shaft 23 Spring 30 Inner head 31 Second bearing 32 Check valve 40 Outer pipe 41 Crown 50 Inner pipe 51 Shoe 60 Liner S Flow path space

Claims (6)

A rotary sampler used for sampling soil samples.
An outer head that can be connected to the tip of the boring rod,
A slide unit having a first bearing, which is rotatably coupled to the tip end side of the outer head with respect to a long axis via the first bearing.
An inner head coupled to the tip side of the slide unit and
The inner tube coupled to the tip side of the inner head and
An outer tube coupled to the tip end side of the outer head, comprising: the slide unit, the inner head, and an outer tube that internally accommodates at least a part of the inner tube.
The slide unit is located in the sliding space, a shaft guide having a sliding space inside, a slide shaft whose rear end is located in the sliding space and whose tip protrudes toward the tip side from the shaft guide. It is characterized by having a spring which is ring-mounted on the slide shaft and elastically biases the slide shaft toward the tip end side with respect to the shaft guide.
sampler. The outer head has a head shaft protruding at the tip, the first bearing is located at the rear end of the shaft guide, and rotatably holds the outer periphery of the head shaft, and the head shaft and the first bearing. The sampler according to claim 1, wherein an oil seal space capable of sealing a lubricant is provided between the bearings. The sampler according to claim 2, wherein the first bearing has a radial ball bearing or a radial roller bearing that can be ringed on the head shaft. A first aspect of the present invention, wherein the inner head has a second bearing, and the inner head is rotatably coupled to the tip end side of the slide shaft via the second bearing with respect to a long axis. The sampler according to any one of 3. An oil seal space in which the second bearing is located at the rear end of the inner head, rotatably holds the outer periphery of the slide shaft, and can seal a lubricant between the slide shaft and the second bearing. The sampler according to claim 4, wherein the sampler is characterized by having. The sampler according to any one of claims 1 to 5, further comprising a tubular liner that can be accommodated inside the inner tube.