Clamp assembly

Abstract

The utility model relates to the field of material engineering experiments, and provides a clamp assembly, which comprises a first clamp, a second clamp and a third clamp, the first clamp is arranged on the inner side of the second clamp, and the second clamp is detachably connected with a testing machine loading head of the stress loading device; the vertical contact face of the first clamp and the second clamp is arranged to be a spherical convex face, the vertical contact face of the second clamp and the first clamp is arranged to be a spherical concave face, and the spherical convex face is matched with the spherical concave face. According to the clamp assembly, the vertical contact face of the first clamp and the second clamp is arranged to be the spherical convex face, the vertical contact face of the second clamp and the first clamp is arranged to be the spherical concave face, and the spherical convex face is matched with the spherical concave face. Therefore, the clamp assembly has the coaxiality deviation self-adjusting function of the sample and the central axis of the loading head of the testing machine, and the accuracy of the test result is high.

Description

Technical Field

[0001] This utility model relates to the field of materials engineering experiments, and more specifically, to a clamp assembly. Background Technology

[0002] Corrosion and related stress corrosion and corrosion fatigue are among the main forms of failure of marine engineering materials, posing a great threat to various marine engineering projects. Obtaining corrosion behavior parameters of marine engineering materials through experiments is an important foundation for marine engineering design, marine engineering material research and development and application.

[0003] The factors leading to material corrosion are numerous and complex. Internal factors include the material itself (primarily determined by composition, microstructure, and internal stress state), with different materials exhibiting different corrosion characteristics. External factors include environmental and load conditions. For marine engineering materials, load conditions affecting corrosion include constant stress loads, slow strain loads, and alternating cyclic loads. Therefore, stress loading devices are needed to test the corrosion performance of samples under different load conditions. During testing, the sample needs to be mounted on the loading head of the stress loading device using clamps.

[0004] Existing technology, patent application number CN201520619338.5, discloses a pin-type specimen clamp for reheat crack sensitivity testing, including an upper adapter and a lower adapter. In use, the specimen clamp is placed in the heating furnace of a testing machine with constant load high-temperature tensile loading function. One end of the upper adapter is threadedly connected to the upper connecting rod of the testing machine, and one end of the lower adapter is threadedly connected to the lower connecting rod of the testing machine. The other end of the upper adapter and the other end of the lower adapter are used to hold the reheat crack specimen, thereby achieving the purpose of clamping the specimen. Although this patent has a simple structure and can utilize existing common testing machines with constant load high-temperature tensile loading function, avoiding the development of specialized testing equipment and resulting in low cost, it lacks a self-adjusting function for the coaxiality deviation between the specimen and the central axis of the testing machine's loading head, leading to lower accuracy in the test results.

[0005] In view of the above, this utility model is hereby proposed. Utility Model Content

[0006] The purpose of this invention is to propose a fixture assembly to solve the problem that existing fixtures do not have a self-adjusting function for the coaxiality deviation between the sample and the central axis of the loading head of the testing machine, resulting in low accuracy of test results.

[0007] To achieve the above objectives, the technical solution of this utility model is implemented as follows:

[0008] A clamping assembly for mounting a specimen on a stress loading device, the clamping assembly comprising:

[0009] A first clamp, wherein the first clamp is detachably connected to the sample;

[0010] The second clamp is disposed inside the first clamp, and the second clamp is detachably connected to the testing machine loading head of the stress loading device;

[0011] The vertical direct contact surfaces of the first clamp and the second clamp are configured as spherical convex surfaces, and the vertical direct contact surfaces of the second clamp and the first clamp are configured as spherical concave surfaces, wherein the spherical convex surfaces and the spherical concave surfaces cooperate with each other.

[0012] The fixture assembly of this utility model has a spherical convex surface on the vertical direct contact surface between the first fixture and the second fixture, and a spherical concave surface on the vertical direct contact surface between the second fixture and the first fixture. The spherical convex surface and the spherical concave surface cooperate to form a connecting contact surface, so that the fixture assembly has a self-adjusting function for the coaxiality deviation between the specimen and the central axis of the loading head of the testing machine, resulting in high accuracy of the test results. Under the premise of ensuring that the specimen is in a uniaxial stress state during the application of uniaxial tensile load test, the requirement for coaxiality of the loading head of the testing machine is reduced.

[0013] Furthermore, a first mounting hole is provided on the first fixture, and a second mounting hole is provided on the second fixture. The first mounting hole and the second mounting hole cooperate with each other, and the sample passes through the second mounting hole and is installed in the first mounting hole.

[0014] Furthermore, the second mounting hole is provided on one side of the second fixture, and a third mounting hole is provided on the opposite side of the second fixture. The third mounting hole is used to mount the first fixture and the testing machine loading head.

[0015] Furthermore, a first mounting part and a second mounting part are provided inside the third mounting hole. The first mounting part is located on the side close to the second mounting hole and is used to mount the first clamp. The second mounting part is located on the side away from the second mounting hole and is used to mount the loading head of the testing machine.

[0016] Furthermore, the first clamp is threadedly connected to the sample, with a first internal thread provided in the first mounting hole and a first external thread provided on the outside of the sample, the first internal thread engaging with the first external thread.

[0017] Furthermore, the second clamp is threadedly connected to the loading head of the testing machine, with a second internal thread provided on the inner side of the second mounting part and a second external thread provided on the outer side of the loading head of the testing machine, the second internal thread and the second external thread cooperating with each other.

[0018] Furthermore, mounting and disassembly holes are provided on the first fixture.

[0019] Furthermore, the projection shape of the first clamp in the direction perpendicular to the central axis of the first mounting hole is a regular hexagon. The diameter of the circumscribed circle of the regular hexagon of the first clamp is denoted as d12, the radius of the spherical convex surface is denoted as R1, and the radius of the spherical concave surface is denoted as R2. R1 satisfies equation (3), and R2 satisfies equation (9).

[0020] (3);

[0021] (9).

[0022] Furthermore, the tooth tip diameter of the first external thread is denoted as d11, the tooth tip diameter of the second external thread is denoted as d22, the height of the first mounting hole in the direction of the central axis is denoted as h11, and d12 satisfies equation (2).

[0023] (2).

[0024] Furthermore, the clamp assembly is made of metal.

[0025] The present invention provides a clamping assembly, which, compared with the prior art, has the following advantages:

[0026] 1) The clamp assembly of this utility model has a spherical convex surface on the vertical direct contact surface between the first clamp and the second clamp, and a spherical concave surface on the vertical direct contact surface between the second clamp and the first clamp. The spherical convex surface and the spherical concave surface cooperate to form a connecting contact surface, so that the clamp assembly has a self-adjusting function for the coaxiality deviation between the specimen and the central axis of the loading head of the testing machine, and the test results are highly accurate. Under the premise of ensuring that the specimen is in a uniaxial stress state during the uniaxial tensile load test, the requirements for the coaxiality of the loading head of the testing machine are reduced.

[0027] 2) The clamp assembly described in this utility model makes sample installation and disassembly easy.

[0028] 3) The clamping assembly described in this utility model occupies less space and has lower manufacturing costs compared with hydraulic clamps. Attached Figure Description

[0029] Figure 1This is a schematic diagram of the installation cross-sectional structure of a clamp assembly according to an embodiment of the present utility model;

[0030] Figure 2 for Figure 1 Enlarged structural diagram at point A;

[0031] Figure 3 This is a front view of the first clamp of a clamping assembly according to an embodiment of the present utility model;

[0032] Figure 4 This is a top view of the first clamp of a clamp assembly according to an embodiment of the present utility model;

[0033] Figure 5 for Figure 4 A sectional perspective view of the center section line AA;

[0034] Figure 6 This is a front view of the second clamp of a clamping assembly according to an embodiment of the present utility model;

[0035] Figure 7 This is a top view of the second clamp of a clamp assembly according to an embodiment of the present utility model;

[0036] Figure 8 for Figure 7 A sectional perspective view of the mid-section line BB.

[0037] Explanation of reference numerals in the attached figures:

[0038] 1. First clamp; 11. First mounting hole; 111. First internal thread; 12. Spherical convex surface; 13. Mounting / removal hole; 2. Second clamp; 21. Second mounting hole; 22. Third mounting hole; 221. First mounting part; 222. Second mounting part; 2221. Second internal thread; 23. Spherical concave surface; 3. Specimen; 31. First external thread; 4. Stress loading device; 41. Testing machine loading head; 411. Second external thread. Detailed Implementation

[0039] It should be noted that, where there is no conflict, the embodiments and features in the embodiments of this utility model can be combined with each other. The descriptions of "first," "second," etc., mentioned in the embodiments of this utility model are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope claimed by this utility model.

[0040] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. Example 1

[0041] This embodiment proposes a clamping assembly, such as Figures 1-8 As shown, the clamping assembly is used to mount the sample 3 onto the stress loading device 4, and the clamping assembly includes:

[0042] First clamp 1, the first clamp 1 is detachably connected to the sample 3;

[0043] The second clamp 2 is disposed inside the first clamp 1, and the second clamp 2 is detachably connected to the testing machine loading head 41 of the stress loading device 4.

[0044] The vertical direct contact surfaces of the first clamp 1 and the second clamp 2 are configured as spherical convex surfaces 12, and the vertical direct contact surfaces of the second clamp 2 and the first clamp 1 are configured as spherical concave surfaces 23, wherein the spherical convex surfaces 12 and the spherical concave surfaces 23 cooperate with each other.

[0045] This embodiment proposes a fixture assembly in which the vertical direct contact surfaces of the first fixture 1 and the second fixture 2 are configured as spherical convex surfaces 12, and the vertical direct contact surfaces of the second fixture 2 and the first fixture 1 are configured as spherical concave surfaces 23. The spherical convex surfaces 12 and spherical concave surfaces 23 cooperate to form a connecting contact surface, so that the fixture assembly has a self-adjusting function for the coaxiality deviation between the specimen 3 and the central axis of the loading head 41 of the testing machine, resulting in high accuracy of the test results. Under the premise of ensuring that the specimen 3 is in a uniaxial stress state during the uniaxial tensile load test, the requirement for the coaxiality of the loading head 41 of the testing machine is reduced.

[0046] Specifically, both the upper and lower ends of the sample 3 are mounted on the stress loading device 4 via the clamp assembly.

[0047] Specifically, the stress loading device 4 is used to apply corresponding force loads to all specimens 3 according to the set test parameter requirements. The force loads include slow strain rate tensile loads and cyclic loads.

[0048] The stress loading device 4 includes other related components in addition to the testing machine loading head 41. Since the specific structure and assembly relationship of the related components are existing technologies, they will not be described in detail here.

[0049] Specifically, a first mounting hole 11 is provided on the first fixture 1, and a second mounting hole 21 is provided on the second fixture 2. The first mounting hole 11 and the second mounting hole 21 cooperate, and the sample 3 passes through the second mounting hole 21 and is installed in the first mounting hole 11.

[0050] Specifically, the second mounting hole 21 is provided on one side of the second clamp 2, and the third mounting hole 22 is provided on the opposite side of the second clamp 2. The third mounting hole 22 is used to install the first clamp 1 and the testing machine loading head 41.

[0051] Specifically, a first mounting part 221 and a second mounting part 222 are provided inside the third mounting hole 22. The first mounting part 221 is located on the side close to the second mounting hole 21 and is used to mount the first clamp 1. The second mounting part 222 is located on the side away from the second mounting hole 21 and is used to mount the testing machine loading head 41.

[0052] Specifically, the first clamp 1 is threadedly connected to the sample 3, a first internal thread 111 is provided in the first mounting hole 11, and a first external thread 31 is provided on the sample 3, with the first internal thread 111 and the first external thread 31 cooperating.

[0053] Specifically, the second clamp 2 is threadedly connected to the loading head 41 of the testing machine, and a second internal thread 2221 is provided on the inner side of the second mounting part 222, and a second external thread 411 is provided on the outer side of the loading head 41 of the testing machine. The second internal thread 2221 and the second external thread 411 cooperate with each other.

[0054] Specifically, mounting and disassembly holes 13 are provided on the first clamp 1. This facilitates the mounting or disassembly of the sample 3 when it is inconvenient to use a wrench.

[0055] More specifically, the mounting and disassembly hole 13 is located on the side away from the spherical convex surface 12.

[0056] Specifically, the clamp assembly is made of metal.

[0057] More specifically, the yield strength of the metal material of the clamp assembly is greater than or equal to 0.5 times the yield strength of the material of the sample 3.

[0058] More specifically, the specimen 3 is a round bar tensile specimen. Connecting portions are provided at both the upper and lower ends of the specimen 3, and the first external thread 31 is provided on the connecting portions.

[0059] Specifically, the tooth tip diameter of the first external thread 31 is denoted as d11, and the tooth tip diameter of the second external thread 411 is denoted as d22. To ensure that the tensile system of the testing machine has sufficient rigidity, d22≥2d11.

[0060] Specifically, the height of the first mounting hole 11 of the first clamp 1 along the central axis is denoted as h11. To ensure that the first clamp 1 has sufficient connection strength, h11 satisfies equation (1):

[0061] (1).

[0062] Specifically, the projection shape of the first clamp 1 in the direction perpendicular to the central axis of the first mounting hole 11 is a regular hexagon, so as to facilitate the installation or removal of the sample 3 with a wrench. The diameter of the circumscribed circle of the regular hexagon is denoted as d12, and d12 satisfies equation (2):

[0063] (2).

[0064] in: To ensure that the first clamp 1 has sufficient connection strength, To ensure that the coaxiality deviation between the sample 3 and the central axis of the loading head 41 of the testing machine is not less than 2°, the self-adjustment range can be adjusted.

[0065] Specifically, the radius of the spherical convex surface 12 is denoted as R1. To ensure that the first clamp 1 has sufficient connection strength, R1 satisfies equation (3):

[0066] (3).

[0067] Specifically, the diameter of the mounting / removal hole 13 is denoted as d13, the depth of the mounting / removal hole 13 is denoted as h12, and the distance between the mounting / removal hole 13 and the central axis of the first mounting hole 11 is denoted as L11. To ensure that the first clamp 1 has sufficient connection strength and can effectively install or remove the sample 3, d13 satisfies equation (4); h12 satisfies equation (5); and L11 satisfies equation (6).

[0068] (4);

[0069] (5);

[0070] (6).

[0071] Specifically, such as Figure 6 As shown, the diameter of the second mounting hole 21 is denoted as d21. To ensure the connection strength of the second clamp 2, d21 satisfies equation (7):

[0072] (7).

[0073] Specifically, such as Figure 6 As shown, the height of the second mounting hole 21 is denoted as h21. To ensure the connection strength of the second clamp 2, h21 satisfies equation (8):

[0074] (8).

[0075] Specifically, such as Figure 6 As shown, the radius of the spherical concave surface 23 is denoted as R2. To ensure that the second clamp 2 and the first clamp 1 can achieve effective contact connection and have sufficient connection strength, R2 satisfies equation (9):

[0076] (9).

[0077] Specifically, the height of the second internal thread 2221 is denoted as h22. To ensure the connection strength between the second clamp 2 and the loading head 41 of the testing machine, h22 satisfies equation (10):

[0078] (10).

[0079] Specifically, the projection shape of the second clamp 2 perpendicular to the central axis of the second mounting hole 21 is a regular hexagon, so as to facilitate the installation and removal of the clamp using a wrench. The diameter of the circumscribed circle of the regular hexagon is denoted as d23. To ensure the connection strength of the second clamp 2, d23 satisfies equation (11):

[0080] (11).

[0081] Specifically, the height of the second clamp 2 is denoted as h23. To ensure the connection effect between the second clamp 2 and the first clamp 1, h23 satisfies equation (12):

[0082] (12).

[0083] More specifically, in this embodiment, the tip diameter of the first external thread 31 is denoted as d11, and the tip diameter of the second external thread 411 is denoted as d22. To ensure sufficient rigidity of the tensile system of the testing machine, in this embodiment, the tip diameter d11 of the first external thread 31 is 16mm, and the pitch is 1mm; the tip diameter d22 of the second external thread 411 is 45mm, and the pitch is 2mm. The dimensional parameters of the first fixture 1 are shown in Table 1, and the dimensional parameters of the second fixture 2 are shown in Table 2.

[0084] In this embodiment, h11=1.25d11=20mm; R1=2.25d12=90mm; d13=0.25d11=4mm; h12=1.25d13=5mm; L11=0.875d11=14mm; d21=1.125d11=18mm; h21=h11=20mm; R2=0.98R1=88mm; h22=d22=45mm; d23=1.78d22=80mm; h23=h21+h22+1.25h11=90mm.

[0085] Table 1 Dimensional parameters of the first fixture

[0086] parameter First internal thread h11 d12 R1 d13 h12 L11 Value (mm) M16×1 20 40 90 4 5 14

[0087] Table 2 Dimensional parameters of the second fixture

[0088] parameter Second internal thread h22 d23 R2 d21 h21 h23 Value (mm) M45×2 45 80 88 18 20 90

[0089] More specifically, this embodiment proposes a fixture assembly in which one end of the sample 3 is first inserted into the second fixture 2, and then the first fixture 1 is threadedly connected to the sample 3. The spherical convex surface 12 of the first fixture 1 and the spherical concave surface 23 of the second fixture 2 form a connecting contact surface. The second fixture 2 is threadedly connected to the loading head 41 of the testing machine, thereby the stress loading device 4 applies a tensile load to the sample 3.

[0090] This embodiment proposes a fixture assembly in which the vertical direct contact surfaces of the first fixture 1 and the second fixture 2 are configured as spherical convex surfaces 12, and the vertical direct contact surfaces of the second fixture 2 and the first fixture 1 are configured as spherical concave surfaces 23. The spherical convex surfaces 12 and spherical concave surfaces 23 cooperate to form a connecting contact surface, so that the fixture assembly has a self-adjusting function for the coaxiality deviation between the specimen 3 and the central axis of the loading head 41 of the testing machine, resulting in high accuracy of the test results. Under the premise of ensuring that the specimen 3 is in a uniaxial stress state during the uniaxial tensile load test, the requirement for the coaxiality of the loading head 41 of the testing machine is reduced.

[0091] Although the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A clamping assembly, characterized in that, The clamping assembly is used to mount the specimen (3) onto the stress loading device (4), and the clamping assembly includes: The first clamp (1) is detachably connected to the sample (3); The second clamp (2) is provided inside the first clamp (1), and the second clamp (2) is detachably connected to the test machine loading head (41) of the stress loading device (4); The vertical direct contact surfaces of the first clamp (1) and the second clamp (2) are configured as spherical convex surfaces (12), and the vertical direct contact surfaces of the second clamp (2) and the first clamp (1) are configured as spherical concave surfaces (23). The spherical convex surfaces (12) and the spherical concave surfaces (23) cooperate with each other.

2. A clamping assembly according to claim 1, characterized in that, A first mounting hole (11) is provided on the first fixture (1), and a second mounting hole (21) is provided on the second fixture (2). The first mounting hole (11) and the second mounting hole (21) are matched. The sample (3) passes through the second mounting hole (21) and is installed in the first mounting hole (11).

3. A clamping assembly according to claim 2, characterized in that, The second mounting hole (21) is provided on one side of the second clamp (2), and the third mounting hole (22) is provided on the opposite side of the second clamp (2). The third mounting hole (22) is used to install the first clamp (1) and the testing machine loading head (41).

4. A clamping assembly according to claim 3, characterized in that, A first mounting part (221) and a second mounting part (222) are provided inside the third mounting hole (22). The first mounting part (221) is located on the side close to the second mounting hole (21) and is used to install the first clamp (1). The second mounting part (222) is located on the side away from the second mounting hole (21) and is used to install the loading head (41) of the testing machine.

5. A clamping assembly according to claim 4, characterized in that, The first clamp (1) is threadedly connected to the sample (3), and a first internal thread (111) is provided in the first mounting hole (11), and a first external thread (31) is provided on the outside of the sample (3). The first internal thread (111) and the first external thread (31) cooperate with each other.

6. A clamping assembly according to claim 5, characterized in that, The second clamp (2) is threadedly connected to the loading head (41) of the testing machine. A second internal thread (2221) is provided on the inner side of the second mounting part (222), and a second external thread (411) is provided on the outer side of the loading head (41) of the testing machine. The second internal thread (2221) and the second external thread (411) cooperate with each other.

7. A clamping assembly according to claim 6, characterized in that, An installation and removal hole (13) is provided on the first clamp (1).

8. A clamping assembly according to claim 6, characterized in that, The first clamp (1) is projected into a regular hexagon in a direction perpendicular to the central axis of the first mounting hole (11). The diameter of the circumscribed circle of the regular hexagon of the first clamp (1) is d12. The radius of the spherical convex surface (12) is R1. The radius of the spherical concave surface (23) is R2. R1 satisfies equation (3) and R2 satisfies equation (9). （3）； （9）。 9. A clamping assembly according to claim 8, characterized in that, The tooth tip diameter of the first external thread (31) is denoted as d11, the tooth tip diameter of the second external thread (411) is denoted as d22, the height of the first mounting hole (11) in the direction of the central axis is denoted as h11, and d12 satisfies equation (2). （2）。 10. A clamping assembly according to claim 1, characterized in that, The clamp assembly is made of metal.

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