Device and system for measuring clamping force of fastener

Abstract

The utility model relates to a device and system for measuring the clamping force of a fastener, and the device comprises a first pull head which is provided with a first connecting hole; the second pull head is provided with a second connecting hole, and a fastener penetrates through the first connecting hole and the second connecting hole, so that the first pull head and the second pull head are fastened and connected through the fastener; the force sensing element is arranged between the first pull head and the second pull head, and the force sensing element is used for being clamped by the first pull head and the second pull head in the state that the fastener is configured, so that the clamping force between the first pull head and the second pull head is detected through the force sensing element. According to the utility model, the technical problem of poor measurement accuracy of the clamping force of the fastener is solved.

Description

Technical Field

[0001] This utility model relates to the field of fastener performance testing, and further to a device and system for measuring the clamping force of fasteners, particularly to a device and system for measuring the clamping force of aerospace fasteners. Background Technology

[0002] In the aviation industry, due to the working environment, aviation fasteners (structural components used to fix various parts on aircraft, such as rivets, bolts, nuts, and various threaded rivets) need to be tested for clamping force after installation to determine whether the aviation fasteners meet the installation requirements (usually there are minimum clamping force requirements in standards or usage scenarios).

[0003] The commonly used method for measuring the clamping force of fasteners is the paddle shim method, and the main structure of its testing device is as follows: Figure 1 As shown, the two sliders 100 are fastened together by fasteners 400. The position where the fasteners 400 pass through and connect the two sliders 100 is considered a sandwich layer. A gasket 300 is placed between the two sliders 100. The fasteners 400 tighten the two gaskets 300 together. A pre-tensioning paddle 200 is placed between the two gaskets 300. One end of the pre-tensioning paddle 200 is clamped and fixed by the two gaskets 300, and a weight is hung on the other end of the pre-tensioning paddle 200. Figure 1 (Not shown in the image, the weight is generally 500g). After assembly, the clamping action of the two pull heads 100 will cause friction between the two pads 300 and the preload paddle 200. The friction on the preload paddle 200 and the downward force exerted by the weight on the preload paddle 200 ( Figure 1 The tension (perpendicular to the paper surface) remains balanced, and the preload paddle 200 will not deflect; after the test begins, as the testing machine applies tension (perpendicular to the paper surface) to the two pull heads 100 respectively... Figure 1 As the tension in the upper and lower directions increases, the clamping force of the two pull heads 100 on the pre-tension paddle 200 gradually decreases, and the friction between the pad 300 and the pre-tension paddle 200 also gradually decreases. Since the tension of the weight on the pre-tension paddle 200 remains constant, the pre-tension paddle 200 will lose balance at a certain moment and then rotate. Since the tension of the testing machine on the two pull heads 100 at this moment is basically equal to and cancels out the clamping force of the fastener 400 on the two pull heads 100, the tension value of the testing machine at this moment is taken as the measured value of the clamping force of the fastener 400.

[0004] Although the above methods are widely used, their measurement process is greatly affected by human factors, which limits the accuracy of the measured values. For fasteners used in the aerospace field, which require precise clamping force measurements, the above methods cannot meet the accuracy requirements.

[0005] Therefore, this utility model proposes a device and system for measuring the clamping force of fasteners to overcome the shortcomings of the prior art. Utility Model Content

[0006] The purpose of this invention is to provide a device for measuring the clamping force of fasteners. By applying a force sensing element to the measurement of the clamping force of fasteners, the measuring device has the advantages of high sensitivity, high precision, and high reliability. It also has a simple structure, is easy to install, and the accuracy of the measurement is not affected by human factors.

[0007] The purpose of this invention is to provide a system for measuring the clamping force of fasteners. Based on the force sensing element for detecting and collecting clamping force, it can meet the subsequent processing needs such as data transmission, storage, and display after data acquisition, and is more convenient for subsequent data recording, traceability, and automated information management.

[0008] The objective of this utility model can be achieved by the following solutions:

[0009] This utility model provides a device for measuring the clamping force of fasteners, comprising:

[0010] A first zipper head, the first zipper head having a first connecting hole;

[0011] The second slider has a second connecting hole. The first connecting hole and the second connecting hole are used for fasteners to pass through them so as to fasten the first slider and the second slider together by means of the fasteners.

[0012] A force sensing element is disposed between the first slider and the second slider, and the force sensing element is clamped by the first slider and the second slider when the fastener is configured, so as to detect the clamping force between the first slider and the second slider by means of the force sensing element.

[0013] In a preferred embodiment of the present invention, the first zipper head has at least a first end face, and the first connecting hole is located on the first end face;

[0014] The second slider has at least a second end face, on which an outwardly protruding boss is provided, and the second connecting hole is located on the end face of the boss.

[0015] In a preferred embodiment of the present invention, when the first pull head and the second pull head are fastened together by the fastener, the force sensing element is clamped between the first end face and the second end face, and the end face of the boss is close to the first end face and has a gap.

[0016] In a preferred embodiment of the present invention, the force sensing element is arranged around the outer periphery of the boss, and the two opposite end faces of the force sensing element are pressed against the first end face and the second end face, respectively.

[0017] In a preferred embodiment of this utility model, the thickness of the force sensing element is greater than the height of the boss.

[0018] In a preferred embodiment of the present invention, the first pull head has a first recess, the first recess is connected to the first connecting hole, and the cross-sectional area of ​​the first recess is greater than the cross-sectional area of ​​the first connecting hole.

[0019] In a preferred embodiment of the present invention, the second pull head has a second recess, which communicates with the second connecting hole, and the cross-sectional area of ​​the second recess is greater than the cross-sectional area of ​​the second connecting hole.

[0020] In a preferred embodiment of the present invention, the force sensing element includes a pressure sensor.

[0021] This utility model provides a system for measuring the clamping force of fasteners, comprising:

[0022] The aforementioned device for measuring the clamping force of fasteners;

[0023] The display, wherein the signal receiving end of the display is electrically connected to the signal output end of the force sensing element in the device for measuring the clamping force of fasteners.

[0024] In a preferred embodiment of the present invention, the system for measuring the clamping force of fasteners further includes a signal amplifier and a signal converter. The signal receiving end of the signal amplifier is electrically connected to the signal output end of the force sensing element, the signal output end of the signal amplifier is electrically connected to the signal receiving end of the signal converter, and the signal output end of the signal converter is electrically connected to the signal receiving end of the display.

[0025] As described above, the features and advantages of the device and system for measuring the clamping force of fasteners of this utility model are:

[0026] The first and second pull heads each have a first connecting hole and a second connecting hole, respectively. The first and second pull heads simulate the actual fastening position of a fastener in its assembled state. The fastener is inserted into the first and second connecting holes, and the first and second pull heads are fastened together by the fastener. A force sensing element is pre-installed between the first and second pull heads. When the fastener fastens the first and second pull heads together, the force sensing element is clamped by the first and second pull heads, allowing direct detection of the clamping force between them. This achieves real-time measurement of the clamping force of the fastener. This device is not only simple in structure, easy to install and operate, but also ensures that other components do not move during the detection process, eliminating the need for manual operation and avoiding inaccurate measurements due to human factors. Furthermore, the sensitivity and accuracy of the force sensing element itself give the measuring device of this application the advantages of high sensitivity, high precision, and high reliability, resulting in better measurement performance. Attached Figure Description

[0027] The following figures are intended only to illustrate and explain the present invention and do not limit the scope of the present invention. Wherein:

[0028] Figure 1 This is a front cross-sectional view of a fastener clamping force measuring device in the prior art;

[0029] Figure 2 This is a partial cross-sectional view of the device for measuring the clamping force of fasteners according to this utility model;

[0030] Figure 3 This is a cross-sectional view of the device for measuring the clamping force of fasteners according to this utility model;

[0031] Figure 4 This is a schematic diagram of the system for measuring the clamping force of fasteners according to this utility model;

[0032] Figure 5 This is a graph showing the change in clamping force of a fastener over time, as detected by the device for measuring the clamping force of a fastener according to this invention.

[0033] The reference numerals in the background art are:

[0034] 100. Puller head; 200. Preloaded paddle;

[0035] 300, gasket; 400, fastener.

[0036] The reference numerals in the accompanying drawings of this utility model are:

[0037] 1. The first slider; 101. The first recess;

[0038] 102. First connecting hole; 103. First end face;

[0039] 2. The second slider; 201. The second concave portion;

[0040] 202. Second connecting hole; 203. Second end face;

[0041] 204. Boss; 3. Force sensing element;

[0042] 4. Signal amplifier; 5. Signal converter;

[0043] 6. Monitor. Detailed Implementation

[0044] The technical solution of this utility model will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that these embodiments are only used to illustrate this utility model and are not intended to limit the scope of this utility model. After reading this utility model, any modifications of this utility model in various equivalent forms by those skilled in the art will fall within the scope defined by the appended claims.

[0045] It should be noted that when an element is referred to as being "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0046] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0047] Implementation Method 1

[0048] like Figure 2 , Figure 3As shown, this utility model provides a device for measuring the clamping force of fasteners. The device includes a first pull head 1, a second pull head 2, and a force sensing element 3. The first pull head 1 has a first connecting hole 102, and the second pull head 2 has a second connecting hole 202. The first connecting hole 102 and the second connecting hole 202 are used for fasteners to pass through, so as to fasten the first pull head 1 and the second pull head 2 together with the fasteners. The force sensing element 3 is disposed between the first pull head 1 and the second pull head 2, and the force sensing element 3 is used to be clamped by the first pull head 1 and the second pull head 2 when the fasteners are configured, so as to detect the clamping force between the first pull head 1 and the second pull head 2 by the force sensing element 3.

[0049] In this invention, the first zipper pull 1 and the second zipper pull 2 ​​each have a first connecting hole 102 and a second connecting hole 202. By coordinating the first zipper pull 1 and the second zipper pull 2, the fastening position of a fastener in its actual assembly state is simulated (such as a clamping layer on a wind turbine fixed by a fastener). The fastener is inserted into the first connecting hole 102 and the second connecting hole 202, thus fastening the first zipper pull 1 and the second zipper pull 2 ​​together. A force sensing element 3 is pre-set between the first zipper pull 1 and the second zipper pull 2. When the fastener fastens the first zipper pull 1 and the second zipper pull 2 ​​together, the force sensing element 3 is clamped by the first zipper pull 1 and the second zipper pull 2. This allows for direct detection of the clamping force between the first pull head 1 and the second pull head 2 (i.e., the clamping force of the fastener on the first pull head 1 and the second pull head 2) via the force sensing element 3, achieving real-time measurement of the clamping force of the fastener. This device is not only simple in structure and easy to install and operate, but also ensures that other components do not move during the detection process, eliminating the need for manual operation and avoiding inaccurate measurements due to human factors. Furthermore, the sensitivity and accuracy of the force sensing element 3 itself give the measuring device of this application the advantages of high sensitivity, high precision, and high reliability, resulting in better measurement performance.

[0050] In one optional embodiment of this utility model, such as Figure 2 , Figure 3As shown, both the first zipper 1 and the second zipper 2 can be, but are not limited to, cylindrical structures. The first zipper 1 has at least a first end face 103, and the first connecting hole 102 is located in the middle of the first end face 103. The second zipper 2 has at least a second end face 203, and the middle of the second end face 203 has an outwardly protruding columnar boss 204. The second connecting hole 202 is located on the second end face 203 and passes through the end face of the boss 204 and through the second zipper 2. When the first zipper 1 and the second zipper 2 are fastened together by fasteners, the force sensing element 3 is clamped between the first end face 103 and the second end face 203. The end face of the boss 204 is close to the first end face 103 and there is a certain gap between the end face of the boss 204 and the first end face 103, or the end face of the boss 204 abuts against the first end face 103. Since a force sensing element 3 needs to be set between the first end face 103 and the second end face 203, and the force sensing element 3 itself has a certain thickness, when the thickness of the force sensing element 3 is large and the length of the fastener to be measured is small, if the first end face 103 and the second end face 203 are far apart due to the setting of the force sensing element 3, the fastener will not be able to fix the first pull head 1 and the second pull head 2 normally and stably. In this case, the present invention sets a boss 204 on the second pull head 2, so that after the first pull head 1, the second pull head 2, the force sensing element 3 and the fastener are assembled, the connection distance of the fastener is shortened, ensuring that the fastener with a small length can also be normally and stably connected to the first pull head 1 and the second pull head 2, thereby ensuring the accuracy of clamping force measurement.

[0051] Furthermore, such as Figure 2 , Figure 3 As shown, the force sensing element 3 is annular. In the assembled state of the first pull head 1, the second pull head 2, the force sensing element 3, and the fastener, the force sensing element 3 is arranged around the outer periphery of the boss 204 of the second pull head 2. One end face of the force sensing element 3 is pressed against the first end face 103 of the first pull head 1, and the other opposite end face of the force sensing element 3 is pressed against the second end face 203 of the second pull head 2. This ensures the stability of the force sensing element 3 assembly and, consequently, the accuracy of the clamping force measurement. It is necessary to ensure that the thickness H of the force sensing element 3 is greater than the height h of the boss 204. This avoids a situation where the height h of the boss 204 is too large, preventing the force sensing element 3 from being clamped tightly by the first end face 103 of the first pull head 1 and the second end face 203 of the second pull head 2.

[0052] Furthermore, such as Figure 2 , Figure 3As shown, the first pull head 1 has a first recess 101, which communicates with the first connecting hole 102. The cross-sectional area of ​​the first recess 101 is larger than that of the first connecting hole 102. The second pull head 2 has a second recess 201, which communicates with the second connecting hole 202. The cross-sectional area of ​​the second recess 201 is larger than that of the second connecting hole 202. The first recess 101 and the second recess 201 facilitate the fastening connection between the fastener and the first pull head 1 and the second pull head 2 (i.e., the fastener is inserted into the first connecting hole 102 and the second connecting hole 202 through the first recess 101 or the second recess 201). In addition, internal threads can be provided on the inner wall of the first recess 101 and / or the inner wall of the second recess 201 to facilitate the disassembly of the sample after the fastener preload is measured.

[0053] In this invention, the force sensing element 3 can be a pressure sensor. Of course, to facilitate the fitting and installation of the force sensing element 3 with the first pull head 1 and the second pull head 2, it can also be a ring-shaped mounting body (to make it easier to fit around the outer periphery of the aforementioned boss 204). The force sensing element 3 is placed inside the mounting body or on the surface of the mounting body, so that the clamping force between the first pull head 1 and the second pull head 2 can be detected when the force sensing element 3 is clamped by the first pull head 1 and the second pull head 2.

[0054] The features and advantages of this utility model for measuring the clamping force of fasteners are:

[0055] I. This novel device for measuring the clamping force of fasteners directly measures the clamping force of fasteners through the force sensing element 3, achieving high measurement accuracy and avoiding errors that may occur with indirect measurement.

[0056] II. This novel device for measuring the clamping force of fasteners avoids human error caused by manual operation and observation during the measurement process. It has a high degree of automation, strong anti-interference ability, higher measurement accuracy, and high detection efficiency, enabling rapid detection of the clamping force of fasteners.

[0057] Third, this new device for measuring the clamping force of fasteners is also applicable to measuring the clamping force of fasteners with shorter lengths, thus having wider applicability.

[0058] IV. This novel device for measuring the clamping force of fasteners measures the clamping force through the force sensing element 3 and can transmit the data. It can monitor the clamping force in real time during the assembly process and can plot the corresponding clamping force-time curve based on the monitoring results, which facilitates the analysis of the installation performance of fasteners and the improvement of fasteners.

[0059] Implementation Method 2

[0060] like Figure 4As shown, this utility model provides a system for measuring the clamping force of fasteners. The system includes the aforementioned device for measuring the clamping force and a display 6. The signal receiving end of the display 6 is electrically connected to the signal output end of the force sensing element 3 in the device for measuring the clamping force. The clamping force data measured by the device for measuring the clamping force can be transmitted to the display 6 for recording and real-time display.

[0061] In this invention, the display 6 can be, but is not limited to, a computer display. It can not only display data through a computer display, but also store and analyze data through a computer.

[0062] Furthermore, such as Figure 4 As shown, the system for measuring fastener clamping force also includes a signal amplifier 4 and a signal converter 5. The signal receiving end of the signal amplifier 4 is electrically connected to the signal output end of the force sensing element 3, the signal output end of the signal amplifier 4 is electrically connected to the signal receiving end of the signal converter 5, and the signal output end of the signal converter 5 is electrically connected to the signal receiving end of the display 6. The signal converter 5 can be, but is not limited to, an analog-to-digital converter, which converts the acquired analog signal into a digital signal and displays it on the display 6, allowing operators to easily monitor the clamping force of the fastener in real time.

[0063] The working process of the system for measuring the clamping force of fasteners according to this utility model is as follows: First pull head 1, second pull head 2, and force sensing element 3 are assembled into place. Then, the fastener is sequentially inserted into the first connecting hole 102 of the first pull head 1 and the second connecting hole 202 of the second pull head 2, thus locking the fastener to the first pull head 1 and the second pull head 2. A clamping force is formed between the fastener and the first pull head 1 and the second pull head 2. During the entire measurement process, the clamping force is transmitted to the force sensing element 3 through the first end face 103 of the first pull head 1 and the second end face 203 of the second pull head 2. The force sensing element 3 generates an electrical signal when pressed (this electrical signal is the detected clamping force signal). This electrical signal is sequentially transmitted to the display 6 after passing through the signal amplifier 4 and the signal converter 5. The clamping force can be displayed in real time in numerical form on the display 6.

[0064] The following is a specific embodiment of this utility model for measuring the clamping force of fasteners (countersunk rivets):

[0065] First, configure the measuring device: Assemble the first pull head 1, the second pull head 2, and the force sensing element 3. Then, electrically connect the force sensing element 3, the signal amplifier 4, the signal converter 5, and the display 6. Clear the clamping force value displayed on the display 6. After starting the measurement, sequentially insert the fasteners into the first connecting hole 102 of the first pull head 1 and the second connecting hole 202 of the second pull head 2, gradually tightening the first pull head 1 and the second pull head 2. During this process, a corresponding force curve will appear synchronously on the display 6. As the clamping force gradually increases, the force curve changes accordingly (i.e., the force curve changes with the application time). Based on the analysis needs, the peak value of the clamping force and the stable value of the clamping force after the fastener assembly and installation (the value of the clamping force after the curve stabilizes) can be obtained. Figure 5 As shown, during the time period 0-t1, the first slider 1, the second slider 2, and the force sensing element 3 are assembled. There is a certain clamping force between the first slider 1 and the second slider 2, but the fastener has not yet applied any force to the first slider 1 and the second slider 2 in the initial stage of assembly. Therefore, the force value detected by the force sensing element 3 does not change during the time period 0-t1. During the time period t1-t2, the continued assembly of the fastener will cause a clamping force to be generated between the first slider 1 and the second slider 2, and the clamping force between the first slider 1 and the second slider 2 will increase as the tightness of the fastener assembly increases. During the time period after t2, the fastener, the first slider 1, and the second slider 2 reach the preset stable assembly state, and the clamping force generated between the first slider 1 and the second slider 2 tends to stabilize and no longer changes. The force value detected at this time is the clamping force under the normal assembly state of the fastener.

[0066] The features and advantages of this utility model system for measuring fastener clamping force are as follows:

[0067] The system for measuring the clamping force of fasteners uses force sensing element 3 to detect and collect data on the clamping force of fasteners. It can meet the subsequent processing needs such as data transmission, storage, and display after data acquisition, and is more convenient for subsequent data recording, traceability, and automated management of information.

[0068] Furthermore, the system for measuring the clamping force of fasteners of this invention has the same features and advantages as the aforementioned device for measuring the clamping force of fasteners, and will not be repeated here.

[0069] It should be noted that in the description of this application, the terms "first," "second," etc., are used only for descriptive purposes and to distinguish similar objects; there is no order between them, nor should they be construed as indicating or implying relative importance. Furthermore, in the description of this application, unless otherwise stated, "multiple" means two or more.

[0070] The various embodiments described in this specification are presented in a progressive manner. The same or similar parts between the embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments.

[0071] The above are merely a few embodiments of this utility model. Although the embodiments disclosed in this utility model are as described above, the content is only for the purpose of facilitating understanding of this utility model and is not intended to limit this utility model. Any person skilled in the art to which this utility model pertains may make any modifications and changes in the form and details of the embodiments without departing from the spirit and scope disclosed in this utility model. However, the patent protection scope of this utility model shall still be determined by the scope defined in the appended claims.

Claims

1. A device for measuring the clamping force of fasteners, characterized in that, include: A first zipper head, the first zipper head having a first connecting hole; The second slider has a second connecting hole. The first connecting hole and the second connecting hole are used for fasteners to pass through them so as to fasten the first slider and the second slider together by means of the fasteners. A force sensing element is disposed between the first slider and the second slider, and the force sensing element is clamped by the first slider and the second slider when the fastener is configured, so as to detect the clamping force between the first slider and the second slider by means of the force sensing element.

2. The device for measuring the clamping force of fasteners as described in claim 1, characterized in that, The first slider has at least a first end face, and the first connecting hole is located on the first end face; The second slider has at least a second end face, on which an outwardly protruding boss is provided, and the second connecting hole is located on the end face of the boss.

3. The device for measuring fastener clamping force as described in claim 2, characterized in that, When the first and second pull heads are fastened together by the fasteners, the force sensing element is clamped between the first and second end faces, and the end face of the boss is close to the first end face and has a gap.

4. The device for measuring fastener clamping force as described in claim 3, characterized in that, The force sensing element is arranged around the outer periphery of the boss, and the two opposite end faces of the force sensing element are pressed against the first end face and the second end face, respectively.

5. The apparatus for measuring fastener clamping force as described in any one of claims 2 to 4, characterized in that, The thickness of the force sensing element is greater than the height of the boss.

6. The apparatus for measuring fastener clamping force as described in claim 3, characterized in that, The first slider has a first recess, which communicates with the first connecting hole, and the cross-sectional area of ​​the first recess is greater than the cross-sectional area of ​​the first connecting hole.

7. The apparatus for measuring fastener clamping force as described in claim 3 or 6, characterized in that, The second pull head has a second recess, which communicates with the second connecting hole, and the cross-sectional area of ​​the second recess is greater than the cross-sectional area of ​​the second connecting hole.

8. The apparatus for measuring fastener clamping force as described in claim 1, characterized in that, The force sensing element includes a pressure sensor.

9. A system for measuring the clamping force of fasteners, characterized in that, include: The apparatus for measuring the clamping force of fasteners as described in any one of claims 1 to 8; The display, wherein the signal receiving end of the display is electrically connected to the signal output end of the force sensing element in the device for measuring the clamping force of fasteners.

10. The system for measuring fastener clamping force as described in claim 9, characterized in that, The system for measuring fastener clamping force further includes a signal amplifier and a signal converter. The signal receiving end of the signal amplifier is electrically connected to the signal output end of the force sensing element, the signal output end of the signal amplifier is electrically connected to the signal receiving end of the signal converter, and the signal output end of the signal converter is electrically connected to the signal receiving end of the display.

Images