JP5513164B2 - Automatic penetration testing machine - Google Patents

Description

  The present invention relates to an automatic penetration testing machine used for determining the hardness of a ground as a preliminary survey of the ground.

  Conventionally, a Swedish sounding test method shown in Non-Patent Document 1 is known as an example of a test for determining hardness of a ground. In this test method, a penetrating rod having a screw point at the tip is vertically projected from the ground, and a weight is placed on the rear end of the penetrating rod in this state. Then, when the load is applied in six stages up to 1KN and the self-sinking is performed only by the load, and the rod does not penetrate even at the maximum load of 1KN, the rod or screw point is rotated under the load so-called rotation. It consists of two stages, a rotation stage that performs penetration.

  Moreover, as an automatic penetration testing machine which performs this test method automatically, there exists a thing shown in patent document 1. FIG. This automatic penetration testing machine is a lifting platform that can be moved up and down along an upright column, a cylindrical chuck that is provided on the lifting platform and that can rotatably hold the penetration rod, and lifts the lifting platform. And elevating drive means. The lifting platform is provided with a powder brake, and the load applied to the lifting platform is adjusted by the braking force of the powder brake to change the load applied to the penetrating rod to a predetermined load. Further, a strain gauge is affixed to the outer periphery of the chuck, and is configured to detect the strain of the chuck that occurs according to the thrust load applied to the penetrating rod. With this configuration, the true load actually applied to the penetrating rod can be known.

Japanese Industrial Standard A1221 (Swedish Sounding Test Method)

JP-A-9-95931

  In the penetration testing machine, a radial load frequently acts on the penetration rod during the test. For this reason, the chuck needs to have a sufficient thickness so as to withstand the load. However, when the wall thickness is increased in this manner, the distortion of the chuck with respect to the thrust load of the penetrating rod becomes insufficient, which hinders detection of the distortion amount by the strain gauge.

The automatic penetration testing machine of the present invention was created in view of the above problems, and is provided on a lifting platform that can be lifted and lowered along a standing column, and as the lifting platform is lowered. A chuck that has a bearing that rotatably supports the penetrating rod that penetrates into the ground, and is provided to move the lifting platform up and down, and the load applied to the penetrating rod can be changed to a predetermined load by adjusting the output torque In the automatic penetration testing machine having a driving means for lifting and lowering, an annular washer type load cell is inserted into the penetration rod, and a penetration rod acting on the bearing is interposed between the washer type load cell and the bearing. A transmission member that transmits the thrust load to the washer-type load cell is interposed, and the thrust load of the penetrating rod is transmitted to the washer-type load cell through these bearings and the transmission member. , Characterized in that it is configured to detect a thrust load applied to the penetration rod from the distortion amount of the washer-type load cell distorted depending on the thrust load of the penetration rod.

  In addition, it is desirable that the transmission member is a pair of angular ball bearings that rotatably support the penetrating rod and are arranged in combination with the back surface.

  In addition, the washer type load cell has an annular shape and receives a thrust load on one side, a plurality of circumferentially formed protrusions on the other side of the load cell main body, and a thrust acting on the load cell main body It is desirable that the apparatus includes a strain detection means for detecting a strain amount of the load cell body that is distorted with the protrusion as a fulcrum according to a load.

  Moreover, it is desirable that a second protrusion having a thickness smaller than that of the protrusion is formed on one surface of the load cell body where the protrusion is formed.

  Further, it is desirable that a plurality of support portions are formed in the circumferential direction on one side of the load cell body that receives the thrust load, and the support portions are configured to receive the thrust load.

  In the automatic penetration testing machine of the present invention, an annular washer type load cell is inserted into the penetration rod, and is distorted by receiving the thrust load of the penetration rod via a bearing that rotatably supports the penetration rod. The thrust load applied to the penetrating rod from is detected. Thus, the detection of the thrust load can be realized with a relatively simple configuration in which the washer type load cell is inserted. Moreover, since the radial load acting on the penetrating rod is received by the bearing, it does not act on the washer type load cell. Therefore, the washer-type load cell can be designed to be thin, and a sufficiently large distortion occurs even at a low thrust load, so that a low thrust load can be detected.

  A transmission member for transmitting a thrust load acting on the bearing to the washer type load cell is interposed between the washer type load cell and the bearing. Accordingly, only the thrust load is transmitted to the washer type load cell via the transmission member, so that no noise acts on the washer type load cell and the detection accuracy is excellent.

  Furthermore, a pair of angular contact ball bearings arranged to support the penetrating rod rotatably and to be combined with the back surface are excellent in thrust load transmission effect and also have load capacity for radial load. By using this instead of the transmission member, the detection accuracy is further improved.

  In addition, in the washer type load cell, the protrusion becomes a fulcrum by a simple process of forming a protrusion on one side of the load cell body, and the load cell body is distorted. Moreover, the amount of distortion with respect to the thrust load is large, and the detection accuracy of the low thrust load is excellent.

  Further, a second protrusion having a thickness smaller than that of the protrusion is formed on one surface of the load cell body where the protrusion is formed. Therefore, when a predetermined or higher thrust load is applied to the load cell body, the second protrusion comes into contact with some member that receives the load cell body. Therefore, distortion beyond the contact point does not occur in the load cell body, and there is no risk of damage to the load cell body due to overload of the thrust load.

  In addition, it is configured to receive a thrust load at a support portion formed on the load cell body. Therefore, the bending moment acting on the load cell body increases and the amount of distortion of the load cell body also increases when the thrust load is received by the support portion, rather than the configuration in which the thrust load is received by the entire surface of one side of the load cell body. Therefore, the detection accuracy of the lower thrust load is superior.

It is a perspective view of the automatic penetration testing machine of the present invention. It is a side view of the automatic penetration testing machine of the present invention. FIG. 3 is a partially cutaway cross-sectional view taken along line AA in FIG. 2. It is the expansion perspective view explanatory view which looked at the principal part of the automatic penetration testing machine of the present invention from the front. It is the expansion perspective explanatory view which looked at the principal part of the automatic penetration testing machine of the present invention from back. FIG. 5 is a cross-sectional view taken along line AA in FIG. 4, (a) before the second one-way clutch is operated, and (b) after the second one-way clutch is operated. It is a principal part expanded sectional view of the automatic penetration testing machine of this invention. It is the expansion perspective view explanatory view which looked at the principal part of the automatic penetration testing machine of the present invention from the lower part. It is the expansion perspective explanatory view which looked at the principal part of the automatic penetration testing machine of the present invention from the upper part.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In FIG. 1, reference numeral 1 denotes an automatic penetration testing machine, which has a lifting platform 3 that can be moved up and down along a column 2. The elevator 3 has a weight 3 a having a predetermined weight, a chuck motor 6 which is an example of a rotation driving means, a chuck 5 which can be rotated by the drive of the chuck motor 6, and the chuck 5. The rod 4a is provided with a penetrating rod 4 having a screw point 4b at the tip of the rod 4a, and a lifting motor 8 as an example of a lifting drive means for moving the lifting platform 3 up and down. Has been. Further, as shown in FIG. 2, the lifting platform 3 has a sprocket 7 that rotates along a guide chain 2a that is arranged vertically along the support column 2, and the sprocket 7 rotates along the guide chain 2a. It is configured to move up and down. The penetrating rod 4 can be loaded with a load of 1 KN due to the lift 3 and the total weight loaded on the lift 3.

  Next, the function of preventing the drop of the lifting platform 3 in the automatic penetration testing machine 1 of the present invention will be described with reference to FIGS.

  As shown in FIGS. 3 and 4, the sprocket 7 is connected so as to rotate integrally with the transmission shaft 12 via the planetary gear mechanism 11. A drive gear 13, an intermediate gear 14, and a transmission gear 15 are rotatably provided on the drive shaft 8 a capable of rotating in the forward / reverse direction of the lifting / lowering motor 8 as the lifting / lowering motor 8 is driven. The transmission shaft 12 is connected via the gear train and the first one-way clutch 16. Specifically, the transmission gear 15 is formed in a cylindrical shape and has external teeth on its peripheral surface. A first one-way clutch 16 as an example of the rotating member described in the claims is press-fitted into the transmission gear 15 so as to rotate integrally with the transmission gear 15, and is attached to the transmission shaft 12. It is supported rotatably. By the action of the first one-way clutch 16, the drive of the lifting motor 8 is transmitted to the sprocket 7 only in the direction in which the lifting platform 3 is lifted. Further, a rotary encoder 17 is provided at the tip of the transmission shaft 12 so that a pulse signal accompanying the rotation of the sprocket 7 can be output. And the control apparatus 10 mentioned later for details processes the pulse signal which the said rotary encoder 17 emits, and calculates | requires the penetration amount, penetration speed, etc. of the penetration rod 4. FIG.

  Here, in addition to the first one-way clutch 16, a second one-way clutch 18 is also rotatably supported on the transmission shaft 12. However, the second one-way clutch 18 is built in the transmission gear 15, but is not press-fitted into the transmission gear 15, and is normally configured not to rotate integrally with the transmission gear 15. .

  An engagement groove 15 a extending in the circumferential direction is formed on the inner peripheral surface of the transmission gear 15. On the other hand, a groove is formed in the outer ring of the second one-way clutch 18, and an engagement piece 18a is fitted therein. The engagement piece 18a is inserted into the engagement groove 15a. Further, the engagement piece 18 a of the first one-way clutch 18 and the transmission gear 15 are connected by a spring 19. Thereby, the second one-way clutch 18 is configured to be pulled by the spring 19 and to rotate and follow the rotation of the rotating member due to the elastic action of the spring 19. With this configuration, as shown in FIG. 6A, when the first one-way clutch 16 exhibits a normal clutch action, the engagement groove 15a and the engagement piece 18a are not engaged. The second one-way clutch 18 follows the transmission gear 15 by the contact friction and the spring 19 described above. On the other hand, when the first one-way clutch 16 is damaged and loses the clutch action, the second one-way clutch 18 and the transmission gear 15 temporarily rotate in the reverse direction, and FIG. As shown in (b), when the engagement piece 18a moves and contacts and engages with the final end 15b of the engagement groove 15a, these rotate integrally.

  With the above configuration, the second one-way clutch 18 is rotatably supported by the transmission shaft 12 so as to follow the rotation of the transmission gear 15, while the first one-way clutch 16 is damaged. When the clutch action is lost, the clutch rotates together with the transmission gear 15. That is, in place of the first one-way clutch 16, the second one-way clutch 18 is configured to exert a clutch action. Thereby, when the first one-way clutch 16 is damaged, there is no danger that the elevator 3 will drop.

  Further, as a detailed description of the above-described second one-way clutch 18 following the transmission gear 15, when the outer ring of the second one-way clutch 18 is pulled by the spring 19 by the rotation of the transmission gear 15 and starts rotating, The transmission shaft 12 has already started rotating due to the clutch action of the first one-way clutch 16. Therefore, since no load is applied between the transmission shaft 12 and the second one-way clutch 18, the second one-way clutch 18 is damaged before or simultaneously with the first one-way clutch 16. The possibility is low. Therefore, when the first clutch is damaged, the second one-way clutch 18 can perform the clutch action almost certainly instead.

  Furthermore, when the first one-way clutch 16 is damaged and loses the clutch action and is damaged so as to become free in both the forward and reverse directions, the driving force by the lifting motor 8 is not transmitted to the sprocket 7, Therefore, the weight of the lifting platform 3 and various components loaded thereon acts on the second one-way clutch 18. As a result, a clutch action occurs between the inner ring of the second one-way clutch 18 and the transmission shaft 12, and the second one-way clutch 18 rotates. On the other hand, since the transmission gear 15 continues to rotate by driving the elevating motor 8, it is relatively reversely rotated. Therefore, the second one-way clutch 18 and the transmission gear 15 are temporarily rotated relatively in the reverse direction so that the engagement piece 18a moves and engages with the engagement groove 15a. It is configured to rotate. With such a relatively simple configuration, the second one-way clutch 18 and the transmission gear 15 can be rotated together. In addition, switching from the first one-way clutch 16 to the second one-way clutch 18 is also accurate and quick.

  Further, as shown in FIG. 5, a detection member 35 is attached to one surface of the transmission gear 15, and is arranged so that the proximity sensor 36 detects this. Moreover, since the engaging piece 18a attached to the second one-way clutch 18 is arranged so that a part thereof protrudes from one side of the transmission gear 15, the proximity sensor 36 also includes the engaging piece 18a. To detect. Therefore, before and after the damage of the first one-way clutch 16, the second one-way clutch 18 and the transmission gear 15 temporarily rotate relatively in the reverse direction, and the distance between the engagement piece 18 a and the detection member 35 is increased. Since the change occurs, the detection signal pattern by the proximity sensor 36 changes. This detection signal is transmitted to the control device 10 which will be described in detail later, and is configured to detect damage to the first one-way clutch 16.

  Hereinafter, the detection mechanism of the thrust load applied to the penetration rod 4 of the automatic penetration testing machine 1 of the present invention will be described.

  As shown in FIG. 7, the chuck 5 is connected to a chuck motor 6 provided on the lifting platform 3 and an endless chain 6a so as to be rotatable. The chuck 5 is configured to hold the penetration rod 4 by fitting the steel ball 20 into the concave groove 4c of the penetration rod 4, and the inner cylinder 21 that can rotate integrally with the held penetration rod 4 is provided. Have. The cylinder 21 is an example of a bearing described in the claims, and is rotatably supported by a pair of cylindrical roller bearings 22 and 23 having a load capacity against a radial load.

  Further, between the pair of cylindrical roller bearings 22 and 23, a pair of angular ball bearings 24 and 25, which are an example of a thrust load transmission member and are combined in the back surface, rotatably support the cylinder 21. Is intervening. Furthermore, between one cylindrical roller bearing 22 and one angular ball bearing 24, a washer type load cell 26, which is an example of a load detecting means, is inserted into the cylinder 21 via a collar 27 and interposed.

  The washer type load cell 26 is configured as shown in FIGS. 8 and 9 and has a load cell body 28 having an annular shape. As shown in FIG. 8, support portions 29a, 29b, 29c, and 29d extending in the axial direction are formed at four locations in the circumferential direction in the vicinity of the large-diameter circular periphery on one side of the load cell main body 28. Further, the support portions 29a, 29b, 29c, and 29d are formed in a stepped shape, and are configured so that a circumferential edge of the outer ring of the angular ball bearing 24 is fitted therein to receive a thrust load.

  On the other hand, as shown in FIG. 9, protrusions 30a, 30b, 30c, and 30d are formed at four locations in the circumferential direction on the other surface of the load cell main body 28. The protrusions 30a, 30b, 30c, 30d is arranged so that the phase in the circumferential direction is different from that of the support portions 29a, 29b, 29c, and 29d. An annular receiving member 31 is inserted into the cylinder 21 so as to come into contact with the protrusions 30a, 30b, 30c, and 30d. This receiving member 31 is for receiving the load cell main body 28 that is intended to move in the axial direction in response to a thrust load, and its one surface is in contact with the protrusions 30a, 30b, 30c, 30d as described above, The other side is arranged so as to be in contact with one side of the cylindrical roller bearing 22.

  Further, on one surface of the load cell main body 28 where the protrusions 30a, 30b, 30c, 30d are formed, second protrusions 32a, 32b, 32c, 32d having a thinner thickness are formed at four locations in the circumferential direction. Has been. The second protrusions 32a, 32b, 32c, and 32d are arranged so that the phases in the circumferential direction are the same with respect to the support portion.

  Further, as shown in FIG. 9, a strain gauge 33a, which is an example of a strain detecting means, is affixed between the protrusion 30d and the second protrusion 32d, and the back surface thereof is also shown in FIG. Thus, the strain gauge 33b is affixed. Further, the strain gauges 33 c and 33 d are also affixed to both surfaces of the load cell main body 28 at positions where the strain gauges 33 a and 33 b are opposed to each other via the central axis of the cylinder 21. These strain gauges 33a, 33b, 33c, and 33d are incorporated in a bridge circuit to constitute a load sensor, and a strain that is a minute change amount of the load cell main body 28 is detected as an electric signal.

  A wave washer 34 is interposed between one angular ball bearing 25 and one cylindrical roller bearing 23. The wave washer 34 applies preload to each of the above-described components inserted into the cylinder 21 so that no gap is generated between the components. Here, the wave washer 34 has a wave shape on both surfaces, and is configured to be elastically deformed by being pressed. Instead of the wave washer 34, rubber packing may be used as an example of an elastically deformable part.

  Subsequently, a transmission path of the thrust load acting on the cylinder 21 will be described. 7 indicates a thrust load transmission path. First, when a thrust load acts on the penetrating rod 4, the thrust load also acts on the cylinder 21 that holds the thrust load. The flange portion 21 a presses the inner ring of the cylindrical roller bearing 23. A thrust load is transmitted from the inner ring to the inner ring of the adjacent angular ball bearing 25 via the wave washer 34. Here, in the angular ball bearings 24 and 25, the ball and the inner ring and the outer ring have contact angles. Therefore, the thrust load transmitted to the inner ring is reliably transmitted to the outer ring through the balls by arranging the back surfaces of the two angular ball bearings 24 and 25 in combination.

  Subsequently, the thrust load transmitted to the outer ring of the angular ball bearing 24 is transmitted to the support portions 29a, 29b, 29c, 29d of the load cell main body 28. In response to this, the protrusions 30 a, 30 b, 30 c, 30 d formed on the load cell main body 28 press the receiving member 31. Therefore, the load cell main body 28 is distorted with the protrusions 30a, 30b, 30c, 30d as fulcrums. That is, in the load cell main body 28, the adjacent protrusion 30a and protrusion 30d, protrusion 30d and protrusion 30c, protrusion 30c and protrusion 30b, and protrusion 30b and protrusion 30a function as beams. Distortion occurs. Here, the second protrusions 32 a, 32 b, 32 c, and 32 d are formed on one surface of the load cell main body 28. Accordingly, when a predetermined distortion occurs, the second protrusions 32a, 32b, 32c, and 32d come into contact with the receiving member. Therefore, the load cell main body 28 is protected from being damaged by an overload of the thrust load.

  As described above, in the configuration for detecting the thrust load, the cylinder 21 is rotatably supported by the pair of cylindrical roller bearings 22 and 23. The cylindrical roller ball bearings 22 and 23 have a load capability with respect to a radial load acting on the cylinder 21, but do not have a load capability with respect to a thrust load. In addition, by arranging the rear surfaces of the angular ball bearings 24 and 25 in combination, the thrust load is reliably transmitted to the outer ring. Therefore, the washer type load cell 26 is affected by the radial load, and there is no possibility that the washer type load cell 26 is distorted by mistake, and the thrust load is reliably transmitted to the washer type load cell 26. The acting thrust load can be detected with high accuracy.

  Moreover, in the load cell main body 28, when one surface receives a thrust load, the protrusions 30a, 30b, 30c, and 30d formed on the opposite one surface serve as fulcrums, and the load cell main body 28 is distorted. In addition, support portions 29a, 29b, 29c, and 29d are formed on the back surface at predetermined intervals in the circumferential direction from the protrusions 30a, 30b, 30c, and 30d, and the support portions 29a, 29b, 29c, and A thrust load acts on the stepped portion of 29d. As a result, the load cell main body 28 is composed of a plurality of beams, and by connecting the strain gauges 33a, 33b, 33c, and 33d in a bridge manner, a large output can be obtained even with a low thrust load. Therefore, the thrust load detection accuracy is excellent.

  The strain gauges 33 a, 33 b, 33 c, 33 d of the washer type load cell 26 are connected to the control device 10 and are configured to send a detection value due to strain of the load cell main body 28 to the control device 10.

  Hereinafter, feedback control of the elevating motor 8 based on the detection value by the washer type load cell 26 which is an example of the load detecting means will be described.

  The control device 10 controls the operation of the automatic penetration testing machine 1 so as to correlate drive control of the elevating motor 8 and chuck motor 6 and load setting according to the penetration status. It is configured. In addition, a command value for energizing the elevating motor 8 for each predetermined load is registered in the control device 10. When the predetermined load is set, the command value is selected, and this command value is output to the elevating motor 8. Thus, a predetermined load is applied to the penetrating rod 4. Further, the control device 10 is configured to feed back the detection value obtained by the washer-type load cell 26, and is configured to compare the fed back detection value with the command value. When there is a difference between the command value and the detected value, the command value of the lifting / lowering motor 8 is corrected repeatedly, and the load applied to the penetrating rod 4 is controlled to be a target value. .

  In the automatic penetration testing machine 1, a weight 3 a having a predetermined weight is loaded on the lifting platform 3 at a position where the lifting platform 3 is lifted, the penetration rod 4 is held on the chuck 5, and then lifted by a start command from the control device 10. The motor 8 is driven. At this time, the elevating motor 8 is driven in a direction in which the first one-way clutch 16 idles with respect to the transmission shaft 12 of the sprocket 7, so that the transmission shaft 12 of the sprocket 7 is driven by the first one-way clutch 16. It becomes rotatable within the range of the number of rotations or less, rotates along the guide chain 2a, and lowers the lifting platform 3 along the column 2 by its own weight. Thereby, the elevating platform 3 descends at a constant speed until the penetrating rod 4 contacts the ground surface. Subsequently, when the penetrating rod 4 comes into contact with the ground surface, the detection value by the washer-type load cell 26 rises, so that an initial load of 50 N is applied to the penetrating rod 4.

  In the penetration test, the load applied to the penetration rod 4 is set to six values of 50N, 150N, 250N, 500N, 750N, and 1KN. For example, when the penetration speed becomes slow at a load of 250 N, the load applied to the penetration rod 4 is increased. On the other hand, when the penetration speed increases, the load applied to the penetration rod 4 is reduced. In this way, the command value is changed so that the load increases in the order of 500 N, 750 N, and 1 KN each time the penetration speed becomes slower in the penetration stage. When a load of 1 KN is applied and the penetration speed becomes slow, the chuck motor 6 is driven to rotate the chuck 5 and the penetration rod 47 integrally, and the rotation penetration is performed with the load applied. Is called.

  Subsequently, a corresponding strain is generated in the load cell main body 28 of the washer type load cell 26 according to the thrust load applied to the tip of the penetrating rod 4, and this is detected by the strain gauges 33a, 33b, 33c, 33d. Next, this detected value is fed back to the control device 10 and compared with the command value. At this time, if the detected value and the target value are the same, the command value for determining the energization amount of the elevating motor 8 is not changed.

  On the other hand, when there is a difference between the target value and the detected value, the control device 10 increases or decreases the command value output to the lifting motor 8 according to the difference, and outputs this command value to the lifting motor 8 again. That is, when the detected force of the washer-type load cell 26 is larger than the target value due to the toughness of the elevator 3 or the driving resistance of the drive system, the clutch force of the powder clutch is reduced. The elevating motor 8 is driven so that the load applied to 4 is reduced. On the other hand, when the detected value of the washer type load cell 26 is smaller than the target value, the control device 10 drives the elevating motor 8 so that the load applied to the penetrating rod 4 is increased. As described above, in the automatic penetration testing machine 1, the detection values of the strain gauges 33a, 33b, 33c, and 33d of the washer type load cell 26 are continuously fed back and compared with the target value, and the difference between the two is determined. Thus, the command value output to the lifting motor 8 is corrected. Thereby, it becomes possible to optimize the load actually applied to the penetration rod 4, and the reliability of the penetration test result is also improved.

DESCRIPTION OF SYMBOLS 1 Automatic penetration test machine 2 Support | pillar 2a Guide chain 3 Lifting base 3a Weight 4 Penetrating rod 4a Rod 4b Screw point 4c Recessed groove 5 Chuck 6 Chuck motor 6a Endless chain 7 Sprocket 8 Lifting motor 8a Drive shaft 10 Controller 11 Planetary gear Mechanism 12 Transmission shaft 13 Drive gear 14 Intermediate gear 15 Transmission gear 15a Engaging groove 15b Final end 16 First one-way clutch 17 Rotary encoder 18 Second one-way clutch 18a Engagement piece 19 Spring 20 Steel ball 21 Cylinder 21a Flange Portions 22 and 23 Cylindrical roller bearings 24 and 25 Angular contact ball bearings 26 Washer type load cell 27 Collar 28 Load cell main bodies 29a, 29b, 29c and 29d Support portions 30a, 30b, 30c and 30d Protruding portions 31 Receiving members 32a, 32b, 32c and 32d Second protrusion 33a , 33b, 33c, 33d Strain gauge 34 Wave washer 35 Detection member 36 Proximity sensor

Claims (5)

A lifting platform that can be moved up and down along a standing column, a chuck that is provided on the lifting platform and has a bearing that rotatably supports a penetrating rod that penetrates into the ground as the lifting platform is lowered, and In an automatic penetration testing machine, which is provided to move up and down the lifting platform, and includes an elevating driving means capable of changing the load applied to the penetration rod by adjusting the output torque to a predetermined load,
An annular washer-type load cell is inserted into the penetrating rod, and a transmission member for transmitting the thrust load of the penetrating rod acting on the bearing to the washer-type load cell is interposed between the washer-type load cell and the bearing. The thrust load of the penetrating rod is transmitted to the washer type load cell through these bearings and the transmission member, and the thrust load applied to the penetrating rod is detected from the strain amount of the washer type load cell that is distorted according to the thrust load of the penetrating rod. Automatic penetration testing machine characterized by being. 2. The automatic penetration testing machine according to claim 1 , wherein the transmission member is a pair of angular ball bearings that rotatably supports the penetration rod and is arranged in combination with the back surface. 3. The washer type load cell is
An annular, load cell body that receives a thrust load on one side; and
A plurality of protrusions formed in the circumferential direction on the other side of the load cell body,
According to claim 1 or claim 2, characterized in that it is composed of a distortion detecting means for detecting a distortion amount of the load cell body distorted as a fulcrum the projection in response to a thrust load acting on the load cell body Automatic penetration testing machine. 4. The automatic penetration testing machine according to claim 3 , wherein a second protrusion having a thickness smaller than that of the protrusion is formed on one surface of the load cell body where the protrusion is formed. On one side of a thrust load in the load cell body, the support portion is formed with a plurality of circumferentially to claim 3 or claim 4, characterized in that it is configured to receive a thrust load in the support portion Automatic penetration testing machine as described.

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