JPH079391B2 - Pull-out strength measuring instrument - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a pull-out strength measuring instrument, and particularly to a pull-out strength at the time of pulling out a screw member from a base material to which a screw member is attached. The present invention relates to a pull-out strength measuring instrument capable of displaying a pass / fail judgment result.

(Prior Art) Generally, when a threaded portion is formed on a resin-formed product or a thin plate to screw together other members, in order to obtain sufficient strength of these joined portions, the threaded portion is used as a separate member It is carried out by burying, welding, press fitting or the like. By the way, since the screw member joined to the base material as a separate member ensures the strength of the joint portion, it is necessary to perform a joint strength test of the base material and the screw member. For the bond strength test, the base material is fixed and a tensile force is applied to the screw member. From the tensile force (pulling force) at the start of separation of the base material and the screw member, the maximum bond strength, that is, the base material and the screw member are pulled out. A pull-out strength measuring instrument for measuring strength is used.

As a conventional pull-out strength measuring instrument of this kind, for example,
There is something like the one shown in the figure.

In the figure, reference numeral 1 is a pull-out strength measuring device, and although not shown in detail, for example, an Amsler tensile tester is used. An injection-molded DUT 3 is engaged with the fixed portion 2 of the pull-out strength measuring device 1, and a screw member 5 is attached to a base material 4 of the DUT.
Is buried. That is, the DUT 3 is the screw member 5
Along with this, the base material 4 is preliminarily cut into a size that can be mounted on the fixed portion 2. At the time of measurement, the bolt 6 is screwed into the screw member 5 and the pulling metal 7 of the pull-out strength measuring instrument 1 is attached to the bolt 6.
To apply a force in the upward direction in the drawing, that is, a pulling force for pulling out the screw member 5 from the DUT 3 supported by the fixed portion 2. Then, when the tensile force is increased, the screw member 5 eventually separates from the base material 4 and falls off, but the pull-out strength of the base material 4 and the screw member 5 is measured from the tensile force at the start of separation.

(Problems to be Solved by the Invention) However, in such a conventional pull-out strength measuring instrument, since the pull-out strength measuring instrument 1 is a stationary Amsler tensile tester or the like, the following problems occur. there were.

That is, it is necessary to cut out the DUT 3 in advance according to the fixed portion 2 to form a specific shape, which complicates the preparation work for the measurement. Moreover, since the pull-out strength measuring device 1 is large and stationary, it is almost impossible to measure the pull-out strength of the base material 4 and the screw member 5 at the site of injection molding or the like, which reduces the efficiency of the molding work. There was a problem to do.

In particular, the pulling strength measurement is intended to improve the quality by feeding back the measurement result to the production process of the product, and there has been a demand for a pulling strength measuring instrument that can be easily measured and inspected on site. .

(Object of the Invention) The present invention has been made in view of the above technical problems, and is a small-sized pull-out strength measuring device capable of easily measuring the pull-out strength of a screw member or bringing it into a work site to determine whether it is acceptable or not. The present invention provides a simple pull-out strength measuring device having a structure in which the pull-out strength can be easily measured by utilizing the elastic deformation by providing a portion that elastically deforms in accordance with the tensile force. The purpose is to do.

(Structure of the invention) In order to achieve the above object, the invention according to claim 1 applies a tensile force in a direction of pulling out a screw member from a base material to a base material having a screw part to which the screw member is attached, A pull-out strength measuring instrument for measuring pull-out strength from a hollow outer cylinder member having a seating portion that abuts against a base material, and a screw member penetrating through the outer cylinder member and screwed into the screw member to rotate. A tensile member housed in an outer cylinder member so as to apply a tensile force corresponding to an angle to a screw member, a measuring unit that measures the tensile force generated in the tensile member, and a display that displays the measurement result of the measuring unit. Means is provided, and preferably the measuring means is provided in a thin portion of the outer cylinder member as in the invention according to claim 2. Or, as in the invention according to claim 3, It is characterized in that the seating portion and the tensile member provided on the tubular member detachably attached to the outer tubular member.

According to a fourth aspect of the invention, a pull-out strength measuring instrument for applying a pulling force in a direction of pulling out the screw member from the base material to a base material having a screw part to which the screw member is attached, and measuring pull-out strength from the pulling force. In, a hollow outer cylinder member having a seating portion that abuts the base material and a screw member that penetrates the outer cylinder member and is screwed into the screw member, and is rotated to apply a tensile force corresponding to the rotation angle to the screw member. A tension member accommodated in the outer cylinder member, a first flange portion fixed to the outer cylinder member, a second flange portion attached to the tension member via a bearing, and a first flange portion. And a second flange portion, a thin portion, a measuring means for measuring the deformation in the thrust direction of the thin portion by screwing the tension member to the screw member, and a measurement result by the measuring means. Display means for Details, as in the invention of claim 5, wherein, is characterized in that the seat provided in the outer cylinder member and the tension member is detachably attached to the outer tubular member.

Hereinafter, specific description will be given based on examples of the present invention.

1 to 4 are views showing a first embodiment of the present invention. First, the configuration will be described.

In FIGS. 1 and 2, reference numeral 11 denotes a main body portion (outer cylinder member) of the pull-out strength measuring device 12, and the main body portion 11 is formed in a hollow cylindrical shape with an appropriate thickness that an adult can grasp with one hand. A substantially hollow cylindrical seating attachment 13 of the pull-out strength measuring device 12 is provided at the middle and lower ends. 14 is a measured object including a synthetic resin plate-shaped base material 15 formed by injection molding and a screw member 16 insert-molded in the boss portion 15a of the base material 15, and the pull-out strength of the measured object 14 Is measured by the pull-out strength measuring device 12. In addition, in the present embodiment, the screw member 16 is an embedded nut.

The seat attachment 13 is detachably screwed to the lower end of the main body 11, and a through hole 13a having an inner diameter D is formed in the axial direction. The inner diameter D of the through hole 13a is set to be larger than the maximum outer diameter d of the screw member 16, and when the pull-out strength measuring device 12 measures the pull-out strength of the object to be measured 14, the seating surface 13b of the seat attachment 13 is mounted on the screw member 16a. It is configured to contact the upper end surface of the boss portion 15a around the outer periphery of the. That is, the seating attachment 13 has a function as a seating portion that seats the pull-out strength measuring device 12 on the base material 15 and supports the base material 15 during measurement. Since seating attachments 13 having inner diameters of various sizes are prepared and the seating attachment 13 is detachably provided on the main body 11, the seating attachment 13 corresponding to the maximum outer diameter d of the screw member 16 can be easily installed. Attachment 13
Can be exchanged. Further, since the seat attachment 13 is screwed to the main body 11, the height of the protrusion from the main body 11 can be arbitrarily adjusted by rotating the seat attachment 13.

A tension shaft 17 (tensile member) is fitted in the through hole 13a of the seat attachment 13 coaxially with the seat attachment 13.
The tension shaft 17 penetrates the seat attachment 13 and the tip 17a
Is screwed onto the screw member 16 of the object to be measured 14, and the base end portion 17b is screwed onto the handle 18 provided on the upper portion of the main body portion 11. That is, when the pulling shaft 17 is rotated by the handle 18, the pulling shaft 17 applies a pulling force P corresponding to the turning angle to the screw member 16 while applying a reaction force to the base material 15 side via the main body portion 11. It is coaxially and rotatably housed in the main body 11. Then, similar to the seating attachment 13, a tension shaft 17 having a male thread of various sizes formed on the tip portion 17a is prepared, and the tension shaft 17 is detachably accommodated in the main body portion 11. Therefore, it is possible to easily replace the pulling shaft 17 with a screw diameter that matches the screw diameter of the screw member 16. It should be noted that the boss portion 18a of the handle 18 fitted into the main body portion 11 is provided with a set screw 19 for fixing the pull shaft 17 to the handle 18 after the base end portion 17b of the pull shaft 17 is screwed. At the time of replacement of the tension shaft 17, the tension shaft 17 can be easily removed from the handle 18 by loosening the set screw 19. Further, a groove 18b is formed on the entire outer circumference of the boss portion 18a of the handle 18, and a screw 20 screwed onto the upper portion of the main body portion 11 projects from the inner peripheral surface 11a of the main body portion 11. To engage the groove 18b to rotatably support the handle 18,
At the same time, the handle 18 is prevented from falling off. Further, as shown in FIG. 3, the handle 18 has a handle member 18c which can be projected outward in a radial direction by rotating the handle 18 in a direction perpendicular to its axis. It can be rotated around to ensure sufficient operation torque. The handle member 18c of the handle 18 may be the one as shown in FIG. 4, or a shaft member or the like housed in the handle 18 so as to be retractable outward in the radial direction.

Reference numeral 21 is a compression type load converter, and the load converter 21 is screwed and fixed to the main body 11 by a first flange portion 22 (first flange portion) formed at the lower end portion in the figure, and the upper end portion is The second flange portion 23 (second flange portion) formed on the thrust bearing
It abuts the boss portion 18a of the handle 18 via 25. The second flange portion 23 is attached to the tensile shaft 17 via the thrust bearing 25 and the boss portion 18a, so that the reaction force of the tensile force P generated in the tensile shaft 17 is received as a compressive force. Further, between the first flange portion 22 and the second flange portion 23, a sensing portion 24 as a thin portion that is elastically deformed by receiving the compressive force (that is, the reaction force of the tensile force P) is provided integrally with these. The sensing unit 24 receives the compression force.
A strain gauge 26 as a measuring means for measuring the strain of 24 is attached. The sensing section 24 is a main body section 11 as a tubular body in which the first flange section 22, the second flange section 23 and the sensing section 24 are integrated.
By being screwed and fixed to the
It constitutes a thin portion provided between the flange portion 22 and the second flange portion 23. In addition, the strain gauge 26 is
Distortion (deformation) in the thrust direction provided on the sensing unit 24 of
The tensile force P acting on the tensile shaft 17 is measured from the amount. Specifically, when the sensing unit 24 is compressed and elastically changed, the strain gauge 26 outputs an electric signal proportional to the strain rate of the sensing unit 24, and the output signal of the strain gauge 26 is It is input to the electrical component section 30 via the intermediate terminal 27 and the wirings 28 and 29 of the shield structure. The electrical component unit 30 has a display unit 31, a group of operation switches 32, a zero reset switch 33, and a battery 34, and also has a control circuit including a microcomputer, an amplification unit, and the like (not shown), and an electric signal output from the strain gauge 26. Is amplified, digitally converted, peak-held, and the peak value is constantly displayed on the display unit 31. Further, the electrical component section 30 compares the standard value of the pull-out strength stored in the memory of the microcomputer (preset by the operation switch group 32) with the display value of the display section 31, and the pull-out force deviates from the standard value. In this case, a defect display lamp (not shown) is turned on. Note that sound may be emitted instead of lighting the defect display lamp (pass / fail judgment signal).

Next, the operation will be described.

First, a pull shaft 17 having a screw diameter suitable for the screw member 16 to be measured is attached to the pull-out strength measuring device 12 in advance. Then, at the time of measurement, the seating surface 13b of the seating attachment 13 of the pull-out strength measuring device 12 is brought into contact with the upper end of the boss portion 15a by the base material 15 of the object to be measured 14, and then the handle 18 is rotated to cause the tip of the pull shaft 17 to rotate. The portion 17a is screwed into the screw member 16. When the handle 18 is further rotated and the rotation angle θ of the tension shaft 17 gradually increases from the rotation angle θ ₀ when the seat attachment 13 contacts the base material 15, as shown in FIG. Due to the screw action between the screw members 16, a pulling force P in the direction of pulling out the screw member 16 proportional to the rotation angle θ is applied to the screw member 16. At this time, the seat attachment 13 having an inner diameter D larger than the maximum outer diameter d of the screw member 16 is previously attached to the main body portion 11.
Is attached, and further the tension shaft 17 is a seat attachment.
Since it is coaxial with 13, the seating surface 13 of the seat attachment 13
b automatically adheres to the base material 15 at the outer periphery of the screw member 16, and the reaction force of the tensile shaft 17 is passed through the tip portion 11b of the main body portion 11, the load converter 21, the transmission shaft thrust bearing 25, and the handle 18. Support. Then, the reaction force of the tensile force P generated on the tensile shaft 17 is transmitted to the second flange portion 23 of the load converter 21 in the reverse order of the above-mentioned members, and the tensile force P of the screw member 16 is transmitted to the sensing portion 24. A reverse compressive force equal to is applied. At this time, the thrust bearing 25 acts to reduce the rotational load of the handle 18.

The above-mentioned tensile force generated in the tensile shaft 17 causes the sensitive portion 24 of the load converter 21 to be axially compressed and deformed, and along with this, an electric signal proportional to the tensile force of the screw member 16 is generated by the strain gauge 26 at the intermediate terminal. The electric signal is output to the electric component section 30 via 27 and the wirings 28 and 29, the electric signal is amplified by the amplifying section of the electric component section 30, further converted into a digital value and displayed on the display section 31 so as to be directly readable. The pulling force P in the pulling direction can be measured. Further, by setting the standard value of the pulling force P by operating the operation switch group 32 in advance, it is possible to easily judge the defect from the lighting of the defect display lamp when the pulling strength is insufficient.

When the handle 18 is further rotated, the tensile force P finally becomes the base material.
15 is larger than the coupling force between the screw member 16 and the screw member 16
Begins to escape from the base material 15. At this time, the tensile force P becomes the maximum value (withdrawal force) Pmax shown in FIG. 5, and can be read by the display section 31 of the electrical equipment section 30 having a peak hold function. That is, the pull-out strength of the DUT 14 can be immediately measured at the work site. By forming a lubricating film such as oily or liquid Teflon on the threaded portion of the tip portion 17a of the tension shaft 17 and the threaded portion of the threaded member 16 of the DUT 14, a large pulling force P can be obtained by a small rotating force of the handle 18. Can be generated, and the life of the tension shaft 17 that is repeatedly used can be extended.

When this measurement is completed, operate the zero reset switch 33 with the thumb of one hand holding the body 11 to display the display.
The display value of 31 is set to zero to prepare for the next measurement, or the ON / OFF switch 32a of the operation switch group 32 is pressed to finish the work.

Thus, in this embodiment, the seat attachment
The seating surface 13b of 13 is screwed to the upper end of the boss portion 15a of the base material 15.
The pulling strength measuring device 12 is supported by abutting around the periphery of 16 and the tip portion 17a of the pulling shaft 17 is screwed into the screw member, and the grip 18
Is rotated to apply a tensile force P to the screw member 16, and the sensitive portion 24 of the load converter 21 provided between the main body portion 11 and the tensile shaft 17 is axially compressed and deformed to distort the strain gauge 26 and the electrical equipment. The maximum tensile force Pmax of the screw member 16, that is, the pull-out strength is measured by the portion 30. Then, when the pull-out strength is insufficient, the pass / fail judgment can be made immediately by the lighting of the defect display lamp or the beeping sound, and the worker can easily perform the pull-out strength inspection in a short time. Also, the seat attachment 13 and the tension shaft 17
Can be attached to and detached from the pull-out strength measuring instrument 12 to correspond to the shape and dimensions of the screw member 16 without exchanging the handle 18, and the pull-out strength measuring instrument 12 can be miniaturized to be freely carried and the base metal Since it is not necessary to cut out the portion of the screw member 16 from the screw 15, the pull-out strength of the object to be measured 14 can be easily measured at the work site. The time required for this measurement is shortened to 1/10 to 1/50 of the conventional case using a tensile tester.

Further, in this embodiment, since the sensitive portion 24 is a thin elastically deforming portion and the amount of the deformation is measured by the strain gauge 26,
It is possible to realize a measuring instrument having a simple structure and a very small size. Moreover, the wiring 2 from the load converter 21 to the electrical component
Since 8 and 29 are installed inside the main body 11 while having a shield structure, it is possible to improve noise resistance and prevent disconnection during work, greatly improving the reliability of measurement results and measuring. The operability of the container can also be made extremely good. Further, since the pull shaft 17 is provided with the detachable handle 18, the replacement part of the pull member can be a small part, and the pull-out strength measuring device can be applied to various screw members at low cost. it can. Further, since the handle 18 is provided with the handle member 18c capable of protruding radially outward,
By using the handle member 18c as necessary,
It is possible to easily cope with a screw portion requiring a large turning torque with a small operation torque.

FIG. 6 is a diagram showing a second embodiment of the present invention. In the figure, 41 is a tensile type load converter formed in a tubular shape, and the load converter 41 includes an intermediate part 42 as a thin part and an intermediate part 42.
And a strain gauge 26 for measuring strain (deformation) in the thrust direction of 42. One end of the load converter 41 is fixed to the upper portion of the main body portion 11 with a screw 44 via a first flange portion 43 formed integrally with the intermediate portion 42. Then, the first flange portion 43 is provided with a step portion 43a formed coaxially with the main body portion 11 so as to be smoothly fitted into the inner circumference 11a of the main body portion 11, and the first flange portion 43 is provided. When is fixed to the main body same portion 11, the load converter 41 is automatically positioned coaxially with the tension shaft 17. At the other end of the load converter 41, a cap-shaped second flange portion 45 is provided integrally with the intermediate portion 42, and the lower end of the transmission shaft 46 is in contact with the upper surface of the second flange portion 45. Conduction axis
46 is formed in a hollow cylindrical shape, is coaxially fitted into the load converter 41, and the tension shaft 17 smoothly penetrates the inner circumference. In addition, in this embodiment, the lower end of the transmission shaft 46 is configured to abut the upper surface of the second flange portion 45, but as shown in FIG. Second flange 45
It may be configured to be screwed to the. In any case, any configuration may be used as long as the transmission shaft 46 is provided so as to be coaxial with the load converter 41. On the other hand, a flange portion 46a is formed on the upper end of the transmission shaft 46, and a cylindrical portion of the transmission shaft 46 is provided so that a gap of a predetermined size is provided between the flange portion 46a and the first flange portion 43 of the load converter 41. The height of 46b is set to be larger than the inner depth of the load converter 41. Further, it is possible to implant a rotation stop pin or the like on the first flange portion 43 and engage the pin with the flange portion 46a of the transmission shaft 46 to prevent the rotation with the pulling shaft 17. 47 is the conduction axis
The thrust bearing 47 is interposed between the flange portion 46a of the shaft 46 and the handle 18, and the transmission shaft 46 and the thrust bearing 47 are smoothened so that the transmission shaft 46 and the thrust bearing 47 do not fall off from the body 11 by a retaining ring or the like (not shown). It is positioned so that it can rotate and is fixed to the main body 11. That is, the first flange portion 43, the intermediate portion 42, and the second flange portion 45 of the load converter 41 are integrally fixed to the main body portion 11, and the intermediate portion 42 is a thin portion as a part of the main body portion 11. (Thin portion of the outer cylinder member). It is connected.

According to such a configuration, the seating surface 13b of the seating attachment 13 is brought into contact with the periphery of the screw member 16 of the boss portion 15a of the base material 15,
When the handle 18 is rotated, the tension shaft 17 is rotated and the tip 17a is rotated.
Is screwed onto the screw member 16, and the handle 18 is rotated to
When the rotation angle θ of 17 is increased, a tensile force P is applied to the screw member 16 in the upward direction in the drawing, that is, in the direction of pulling out the screw member 16 from the base material 15. The reaction force of the tensile force P generated in the tension shaft 17 is transmitted to the second flange portion 45 of the load converter 41 via the tension shaft 17, the handle 18, the thrust bearing 47, and the transmission shaft 46, and the first flange portion 43 is the main body. Since it is fixed to the body part 11, the middle part 42
A pulling force equal to the pulling force P of the screw member 16 acts on. Therefore, when the pulling shaft 17 is rotated by the handle 18 and the pulling force P corresponding to the rotation angle θ is applied to the screw member 16, the pulling force equal to the pulling force P is received and the intermediate portion 42 of the load converter 41 is rotated by the shaft. Transforms in the direction. Then, the plurality of strain gauges 26 attached to the outer periphery of the intermediate portion 42 receive the tensile force and are deformed, and output an electric signal proportional to the tensile force P to the electrical equipment section 30. Other configurations and operations are similar to those of the first embodiment, and the same effects as those of the first embodiment can be obtained in this embodiment.

In addition, in the first and second embodiments, the screw member 16 is the embedded nut having the female screw, but as shown in FIG. 8, the male screw member 51 may be insert-molded on the DUT 14. In this case, a female screw 52 corresponding to the male screw member 51 is formed at the tip of the pull shaft 17. In addition, the load converter 21,
Thrust bearing 25 that transmits the reaction force from the screw member 16 to 41,
It goes without saying that other types of bearings that can support the thrust load can be used instead of 47.

(Effect) According to the invention described in claim 1, the tensile member is housed in the outer cylinder member provided with the seating portion for the base material in a penetrating state, and the tensile member is screwed to the screw member attached to the base material. As a result, a tensile force is applied from the screw member to the tensile member housed in the outer cylinder member, and the tensile force is measured by the measuring means and displayed by the display means. (EN) It is possible to provide a small-sized pull-out strength measuring device that can be easily carried around to easily perform pull-out strength measurement or pull-out strength pass / fail inspection. When the outer cylinder member is provided with a thin portion and the measuring means is provided inside the thin portion, the thin portion is made to be an elastically deformable portion in response to a tensile force. Further, it is possible to employ a small measuring means capable of easily measuring the pull-out strength by utilizing the elastic deformation, and it is possible to provide a more compact and simple pull-out strength measuring instrument. Further, as in the invention according to claim 3, if the seat portion and the tension member are detachably provided to the main body portion, the seat portion and the tension member can be appropriately replaced with different shapes to form various screw members. It is possible to provide a pull-out strength measuring device which can be made compatible and has high versatility.

According to the invention described in claim 4, the tensile member is accommodated in the outer cylinder member provided with the seating portion for the base material in a penetrating state, and the tensile member is screwed to the screw member attached to the base material. , A tensile force is applied from a screw member to a tension member housed in the outer cylinder member, and between a first flange portion fixed to the outer cylinder member and a second flange portion attached to the tension member via a bearing. Since the thin portion is formed and the measuring means for measuring the deformation in the thrust direction of the thin portion is provided and the measurement result of the measuring means is displayed on the display means, it can be easily carried to a molding work site or the like. A simple and compact pull-out strength measuring instrument that can measure pull-out force or pass / fail inspection of pull-out strength, and can easily measure pull-out strength by utilizing elastic deformation in the thrust direction of the thin portion. To provide According to the invention described in claim 5, if the seating portion and the tension member are detachably provided to the main body portion, the seating portion and the tension member can be appropriately replaced with those having different shapes to form various screw members. It is possible to provide a pull-out strength measuring device which can be made compatible and has high versatility.

[Brief description of drawings]

1 to 5 are views showing a first embodiment of the pull-out strength measuring device according to the present invention. FIG. 1 is a front sectional view thereof, FIG. 2 is a top view thereof, and FIG. 3 is a perspective view of a handle thereof. FIG. 4 is a perspective view showing another aspect of the handle, FIG. 5 is a graph showing the relationship between the tensile force applied to the screw member and the rotation angle of the handle, and FIGS. 6 and 7 are related to the present invention. It is a figure which shows 2nd Example of the pull-out strength measuring device, FIG. 6 is the front sectional drawing, FIG. 7 is the drawing figure which shows the other aspect of the conduction shaft, FIG. 8 is the 1st, 2nd figure.
Sectional drawing which shows the to-be-measured object and the other aspect of a tension axis | shaft in an Example, FIG. 9 is a schematic block diagram of the conventional drawing strength measuring device. 11 …… Body part (outer cylinder member), 12 …… Pulling strength measuring instrument, 13 …… Seating attachment (seating part), 15 …… Base material, 16 …… Screw member, 17 …… Tensile shaft (tensile member) ), 18 ... Handle, 18c ... Handle member, 21, 41 ... Load transducer, 25, 47 ... Thrust bearing, 26 ... Strain gauge (measuring means), 30 ... Electrical component.

Claims (5)

[Claims] 1. A pull-out strength measuring instrument for measuring a pull-out strength from a tensile force in the direction of pulling out a screw member from a base material to a base material having a threaded portion to which a screw member is attached, and a hollow pulling strength measuring device, An outer cylinder member having a seating portion that abuts on the base material, and an outer cylinder that penetrates the outer cylinder member and is screwed into a screw member and is rotated to apply a tensile force according to a rotation angle to the screw member. A pull-out strength measuring instrument comprising: a tensile member housed in a member; a measuring means for measuring a tensile force generated in the tensile member; and a display means for displaying a measurement result of the measuring means. . 2. The pull-out strength measuring instrument according to claim 1, wherein the measuring means is provided in a thin portion of the outer cylinder member. 3. The pull-out strength measuring device according to claim 1, wherein the seating portion and the tension member provided on the outer cylinder member are detachably provided on the outer cylinder member. 4. A pull-out strength measuring instrument for applying a tensile force to a base material having a threaded portion to which a screw member is attached in a direction for pulling out the screw member from the base material, and measuring the pull-out strength from the tensile force. An outer cylinder member having a seating portion that abuts on the base material, and an outer cylinder that penetrates the outer cylinder member and is screwed into a screw member and is rotated to apply a tensile force according to a rotation angle to the screw member. A tension member housed in the member, a first flange portion fixed to the outer cylinder member, a second flange portion attached to the tension member via a bearing, a first flange portion and a second flange portion. A thin portion provided between the flange portion, a measuring means for measuring the deformation in the thrust direction of the thin portion by screwing the tension member to the screw member, and a display means for displaying the measurement result of the measuring means. And a pull-out strength measuring instrument. 5. The pull-out strength measuring device according to claim 4, wherein the seating portion and the tension member provided on the outer cylinder member are detachably provided on the outer cylinder member.