Double-sided carbon fiber multifilament sample clamping device

Abstract

The utility model discloses a double-sided carbon fiber multifilament sample clamping device. The double-sided carbon fiber multifilament sample clamping device comprises a tensile machine chuck and a pair of clamping assemblies, the tensile machine chuck comprises a clamping seat and a hydraulic column, a wedge-shaped groove is formed in the clamping seat, and one end of the hydraulic column is inserted into the wedge-shaped groove in a sliding mode; the pair of clamping assemblies are each provided with a clamping face and a wedge-shaped face, and the wedge-shaped faces are matched with the wedge-shaped grooves. And the cross section of the clamping surface is arc-shaped. Compared with the prior art, the utility model has the beneficial effects that the central axis of the fiber multifilament sample is collinear with the central axis of the arc-shaped clamping surface of the clamping assembly, so that the centering is completed while the sample piece is clamped, and an additional centering device is not needed; the contact area of the sample and the clamping assembly is increased, the sample surface pressure in a clamping area is reduced, sample damage is prevented, and the test strength and the test stability are improved; the clamping face of a traditional double-face clamp is improved, an original power mechanism and an original transmission mechanism are not changed, and cost can be greatly reduced.

Description

Technical Field

[0001] The utility model belongs to the technical field of carbon fiber testing, in particular to a double-sided carbon fiber multifilament sample clamping device. Background Art

[0002] Carbon fiber is a high-strength, high-modulus, high-temperature resistant special fiber with a carbon content greater than 90%. It uses polyacrylonitrile (PAN), asphalt, viscose fiber, etc. as raw materials and is made through pre-oxidation, carbonization, graphitization and other processes. Among them, PAN-based carbon fiber has developed rapidly and has become the main type of carbon fiber.

[0003] When carbon fiber is used as a structural material, the mechanical properties of multifilament can more intuitively evaluate the quality of carbon fiber. It is currently the most common material performance assessment indicator for carbon fiber manufacturers and application units. However, how to accurately test the mechanical properties of carbon fiber multifilament has always been a difficult problem.

[0004] In the testing process, the clamping of carbon fiber multifilament samples is the key. The traditional fixture is a double-sided fixture, and the clamping method is: under the action of external force (manual, hydraulic, pneumatic, electric, etc.), the two clamping planes approach each other, the contact force between the sample and the fixture surface increases, and the clamping force increases. As long as the clamping force is greater than the sample load, the sample will not be displaced relative to the fixture, so that the fixture clamps the sample. The clamping force is essentially a friction force, and the calculation formula is: F = μ * N, where F is the friction force, μ is the friction coefficient, and N is the contact force between the sample and the fixture surface. The calculation formula for N contact force is: N = p * S, where p is the pressure and S is the force area. It can be concluded from the above formula that the μ friction coefficient is generally a constant. When the same friction force F is provided, the smaller the contact area between the sample and the fixture, the greater the contact force per unit area. In traditional double-sided fixtures, the contact area between the rod-shaped sample and the flat fixture is a straight line, and the contact force per unit area is very large. Carbon fiber multifilament samples are generally considered to be a brittle material. Excessive local pressure can easily cause damage, resulting in stress concentration, reducing the bearing capacity of the spline, and leading to problems such as low strength, abnormal failure mode, and poor data stability.

[0005] Analyzing the formula, we conclude that the solution is to increase the contact area between the sample and the fixture. The traditional double-sided fixture is one of the most widely used grips in tensile testing machines. By improving the clamping surface of the traditional double-sided fixture without changing the original power and transmission mechanisms, we have developed a double-sided carbon fiber multifilament sample clamping device that can cost-effectively solve the aforementioned problems encountered during actual carbon fiber multifilament sample testing.

[0006] Therefore, in order to solve the above technical problems, it is necessary to provide a double-sided carbon fiber multifilament sample clamping device.

[0007] The information disclosed in this background technology section is only intended to increase the understanding of the overall background of the present invention, and should not be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to those skilled in the art. Utility Model Content

[0008] The purpose of the utility model is to provide a double-sided carbon fiber multifilament sample clamping device, which can improve the clamping surface of the traditional double-sided clamp, without changing the original power mechanism and transmission mechanism, increase the contact area between the sample and the clamp, and solve the above-mentioned problems encountered in the actual carbon fiber multifilament sample testing process at a low cost.

[0009] In order to achieve the above-mentioned purpose, the technical solution provided by a specific embodiment of the present invention is as follows:

[0010] A double-sided carbon fiber multifilament sample clamping device, comprising a tensile testing machine chuck and a pair of clamping components;

[0011] The tensile testing machine chuck includes a clamping seat and a hydraulic column, the clamping seat is provided with a wedge-shaped groove, and one end of the hydraulic column is slidably inserted into the wedge-shaped groove;

[0012] A pair of the clamping assemblies are each provided with a clamping surface and a wedge surface, wherein the wedge surface matches the wedge groove;

[0013] The cross section of the clamping surface is arc-shaped, and the arc center angle is 90-150°. The central axis of the clamping surface is collinear with the central axis of the sample.

[0014] In one or more embodiments of the present invention, the clamping surface is a frosted surface.

[0015] In one or more embodiments of the present invention, the diameter of the clamping surface is not less than the diameter of the sample.

[0016] In one or more embodiments of the present invention, the wedge-shaped surface is in an "eight" shape.

[0017] In one or more embodiments of the present invention, the clamping assembly includes a first clamping block, wherein a set of opposite side surfaces of the first clamping block parallel to the sample are respectively provided with a first wedge surface and a first clamping surface;

[0018] Another set of opposite side surfaces on the first clamping block that are parallel to the sample are planes.

[0019] In one or more embodiments of the present invention, the clamping assembly includes a second clamping block, and a set of opposite side surfaces of the second clamping block parallel to the sample are respectively provided with a second wedge surface and a second clamping surface;

[0020] Another set of opposite side surfaces on the second clamping block that are parallel to the sample are cutting surfaces.

[0021] In one or more embodiments of the present invention, the cut surfaces of the opposite sides of the second clamping block are all facing the sample.

[0022] In one or more embodiments of the present invention, the clamping assembly includes a third clamping block, which further includes a clamping seat and a clamping head. A connecting structure is provided between the clamping seat and the clamping head, and the clamping head is detachably assembled on the clamping seat through the connecting structure.

[0023] A third wedge-shaped surface is provided on one side of the clamping seat;

[0024] A third clamping surface is provided on one side surface of the clamping head.

[0025] In one or more embodiments of the present invention, the connecting structure includes a slideway provided on the clamping seat and a slide groove provided on the clamping head, the slideway is located on the opposite side of the third wedge surface, the slide groove is located on the opposite side of the third clamping surface, and the slideway matches the slide groove;

[0026] A pair of fastening screw holes is opened on one side surface of the slideway, and a pair of through holes is opened on one side surface of the slide groove, and the pair of fastening screw holes matches the pair of through holes;

[0027] A pair of through holes are respectively inserted with fastening bolts that match a pair of fastening screw holes.

[0028] In one or more embodiments of the present invention, the cross sections of the slideway and the slide groove are both trapezoidal.

[0029] Compared with the prior art, the beneficial effects of the present invention are:

[0030] 1. The center axis of the fiber multifilament sample is collinear with the center axis of the arc-shaped clamping surface of the clamping assembly. The sample is clamped and aligned at the same time, without the need for an additional centering device.

[0031] 2. Increase the contact area between the sample and the clamping component, reduce the surface pressure of the sample in the clamping area, prevent sample damage, and improve test strength and test stability;

[0032] 3. Improve the clamping surface of the traditional double-sided fixture without changing the original power mechanism and transmission mechanism, which can greatly reduce costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0034] Figure 1 This is a structural diagram of a tensile testing machine chuck of a double-sided carbon fiber multifilament sample clamping device in Examples 1 to 3 of the present utility model;

[0035] Figure 2 This is a schematic structural diagram of a first clamping block of a double-sided carbon fiber multifilament sample clamping device in Example 1 of the present utility model;

[0036] Figure 3 This is a structural diagram of the first clamping block of a double-sided carbon fiber multifilament sample clamping device in Example 1 of the present utility model;

[0037] Figure 4 This is a schematic structural diagram of the second clamping block of a double-sided carbon fiber multifilament sample clamping device in Example 2 of the present utility model;

[0038] Figure 5 This is a structural diagram of the second clamping block of a double-sided carbon fiber multifilament sample clamping device in Example 2 of the present utility model;

[0039] Figure 6 This is a structural diagram of the third clamping block of a double-sided carbon fiber multifilament sample clamping device in Example 3 of the present utility model;

[0040] Figure 7 This is a structural diagram of a clamping base of a double-sided carbon fiber multifilament sample clamping device in Example 3 of the present utility model;

[0041] Figure 8 This is a structural diagram of a clamping head of a double-sided carbon fiber multifilament sample clamping device in Example 3 of the present utility model.

[0042] Description of main reference numerals:

[0043] 10. First clamping block; 11. First wedge-shaped surface; 12. First clamping surface; 13. Plane; 20. Second clamping block; 21. Second wedge-shaped surface; 22. Second clamping surface; 23. Cutting surface; 30. Third clamping block; 31. Clamping seat; 311. Third wedge-shaped surface; 312. Slide; 313. Fastening screw hole; 32. Clamping head; 321. Third clamping surface; 322. Through hole; 323. Slide; 33. Fastening bolt; 40. Sample; 50. Tensile machine chuck; 51. Clamping seat; 511. Wedge-shaped groove; 52. Hydraulic column. DETAILED DESCRIPTION

[0044] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the following will be combined with the drawings of the embodiments of the present invention to clearly and completely describe the technical solutions of the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0045] Example 1

[0046] like Figure 1-Figure 3 As shown, a double-sided carbon fiber multifilament sample clamping device in one embodiment of the present invention includes a tensile testing machine chuck 50 and a pair of clamping components. The tensile testing machine chuck 50 includes a clamping seat 51 and a hydraulic column 52. A wedge-shaped groove 511 is provided on the clamping seat 51. One end of the hydraulic column 52 is slidably inserted into the inside of the wedge-shaped groove 511. The sample can be clamped and released by extending and shortening the hydraulic column 52.

[0047] The clamping assembly includes a first clamping block 10. A first wedge surface 11 and a first clamping surface 12 are provided on a pair of opposing side surfaces of the first clamping block 10, parallel to the sample 40. The first wedge surface 11 is shaped like an "eight," enabling the first clamping block 10 to form a wedge-shaped fit within the wedge-shaped groove 511. The first clamping surface 12 has an arc-shaped cross-section with a center angle of 90-150°. During clamping, the central axis of the first clamping surface 12 is collinear with the central axis of the sample 40, achieving simultaneous alignment during clamping without the need for additional alignment devices.

[0048] In addition, the diameter of the first clamping surface 12 is no less than the diameter of the sample 40. Under normal circumstances, the first clamping surface 12 cannot completely wrap around the sample 40. During clamping, a gap exists between the pair of first clamping blocks 10, facilitating contact quality between the first clamping surface 12 and the sample 40 and achieving preferential contact between the first clamping surface 12 and the sample 40. This ensures effective clamping during clamping, even if there are deviations in the diameters of different samples 40. The arcuate curved surface of the first clamping surface 12 coincides with the cylindrical curved surface of the carbon fiber multifilament sample, reducing surface pressure on the sample 40 in the clamping area.

[0049] Preferably, the first clamping surface 12 is a frosted surface to ensure the stability of clamping.

[0050] In addition, in this embodiment, another set of opposite side surfaces on the first clamping block 10 that are parallel to the sample 40 is a plane 13 .

[0051] Example 2

[0052] like Figure 1 Combine Figure 4 and Figure 5 As shown, a double-sided carbon fiber multifilament sample clamping device in one embodiment of the present invention includes a tensile testing machine chuck 50 and a pair of clamping components. The tensile testing machine chuck 50 includes a clamping seat 51 and a hydraulic column 52. A wedge-shaped groove 511 is provided on the clamping seat 51. One end of the hydraulic column 52 is slidably inserted into the inside of the wedge-shaped groove 511. The sample can be clamped and released by extending and shortening the hydraulic column 52.

[0053] The clamping assembly includes a second clamping block 20. A second wedge surface 21 and a second clamping surface 22 are provided on a set of opposing side surfaces of the second clamping block 20, parallel to the sample 40. The second wedge surface 21 is shaped like an "eight," enabling the second clamping block 20 to form a wedge-shaped fit within the wedge groove 511. The second clamping surface 22 has an arc-shaped cross section with a center angle of 90-150°. When clamped, the central axis of the second clamping surface 22 is collinear with the central axis of the sample 40, achieving simultaneous alignment without the need for additional centering devices.

[0054] Furthermore, the diameter of the second clamping surface 22 is no smaller than the diameter of the sample 40. Under normal circumstances, the second clamping surface 22 cannot completely enclose the sample 40. During clamping, a gap exists between the pair of second clamping blocks 20, facilitating contact quality between the second clamping surface 22 and the sample 40 and achieving preferential contact between the second clamping surface 22 and the sample 40. This ensures effective clamping during clamping, even if the diameters of different samples 40 vary. The arc surface coincides with the cylindrical surface of the carbon fiber multifilament sample, reducing surface pressure on the sample 40 in the clamping area.

[0055] Preferably, the second clamping surface 22 is a frosted surface to ensure the stability of clamping.

[0056] In addition, in this embodiment, another set of opposite side surfaces on the second clamping block 20 that are parallel to the sample 40 is a cut surface 23. The difference from the first embodiment is that the plane 13 where the clamping process does not work is deleted, which is conducive to accurately placing the sample 40 on the second clamping surface 22, thereby improving the accuracy and convenience of the operation.

[0057] Example 3

[0058] like Figure 1 Combine Figure 6-Figure 8 As shown, a double-sided carbon fiber multifilament sample clamping device in one embodiment of the present invention includes a tensile testing machine chuck 50 and a pair of clamping components. The tensile testing machine chuck 50 includes a clamping seat 51 and a hydraulic column 52. A wedge-shaped groove 511 is provided on the clamping seat 51. One end of the hydraulic column 52 is slidably inserted into the inside of the wedge-shaped groove 511. The sample can be clamped and released by extending and shortening the hydraulic column 52.

[0059] The clamping assembly includes a third clamping block 30, which further includes a clamping seat 31 and a clamping head 32. A third wedge surface 311 is provided on one side of the clamping seat 31. The third wedge surface 311 is in an "eight" shape. Through the third wedge surface 311, the third clamping block 30 can form a wedge fit inside the wedge groove 511.

[0060] A third clamping surface 321 is provided on one side of the clamping head 32. This surface 321 has an arc-shaped cross-section with an arc center angle of 90-150°. During clamping, the central axis of the third clamping surface 321 is collinear with the central axis of the sample 40, achieving simultaneous alignment without the need for additional centering devices.

[0061] Furthermore, the diameter of the third clamping surface 321 is no smaller than the diameter of the sample 40. Under normal circumstances, the third clamping surface 321 cannot completely enclose the sample 40. During clamping, a gap exists between the pair of third clamping blocks 30, facilitating contact quality between the third clamping surface 321 and the sample 40 and achieving preferential contact between the third clamping surface 321 and the sample 40. This ensures effective clamping during clamping, even if the diameters of different samples 40 vary. The arc surface coincides with the cylindrical surface of the carbon fiber multifilament sample, reducing surface pressure on the sample 40 in the clamping area.

[0062] Preferably, the third clamping surface 321 is a frosted surface to ensure the stability of clamping.

[0063] A connection structure is provided between the clamping base 31 and the clamping head 32 , and the clamping head 32 is detachably assembled on the clamping base 31 through the connection structure.

[0064] Specifically, the connection structure includes a slide 312 arranged on the clamping seat 31 and a slide groove 323 arranged on the clamping head 32. The slide 312 is located on the opposite side of the third wedge surface 311, and the slide groove 323 is located on the opposite side of the third clamping surface 321. The slide 312 can be slidably inserted into the slide groove 323.

[0065] The cross sections of the slide 312 and the slide groove 323 are both trapezoidal. After the slide 312 is inserted into the slide groove 323 , it can automatically form a limit, which is convenient for operation and improves the structural strength.

[0066] A pair of fastening screw holes 313 are defined on one side of the slideway 312, and a pair of through holes 322 are defined on one side of the slideway 323. The fastening screw holes 313 can overlap with the through holes 322. Fastening bolts 33 matching the fastening screw holes 313 are inserted into the through holes 322. These fastening bolts 33 secure the clamping head 32 to the clamping base 31. With this clamping assembly structure, the clamping head 32 can be flexibly replaced, allowing for interchangeable third clamping surfaces 321 of varying sizes to accommodate samples 40 of varying specifications, enhancing adaptability.

[0067] When in use, the clamping assembly is placed inside the wedge-shaped groove 511 of the tensile testing machine chuck 50, and the sample can be clamped and released by extending and shortening the hydraulic column 52.

[0068] The beneficial effects of the utility model are:

[0069] 1. The center axis of the fiber multifilament sample is collinear with the center axis of the arc-shaped clamping surface of the clamping assembly. The sample is clamped and aligned at the same time, without the need for an additional centering device.

[0070] 2. Increase the contact area between the sample 40 and the clamping assembly, reduce the surface pressure of the sample 40 in the clamping area, prevent sample damage, and improve test strength and test stability;

[0071] 3. Improve the clamping surface of the traditional double-sided fixture without changing the original power mechanism and transmission mechanism, which can greatly reduce costs.

[0072] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the present invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be encompassed within the present invention. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

[0073] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A double-sided carbon fiber multifilament sample clamping device, characterized in that: include: A tensile testing machine chuck, comprising a clamping seat and a hydraulic column, wherein the clamping seat is provided with a wedge-shaped groove, and one end of the hydraulic column is slidably inserted into the interior of the wedge-shaped groove; A pair of clamping assemblies, each of the pair of clamping assemblies is provided with a clamping surface and a wedge surface, wherein the wedge surface matches the wedge groove; The cross section of the clamping surface is arc-shaped, and the arc center angle is 90-150°. The central axis of the clamping surface is collinear with the central axis of the sample.

2. The double-sided carbon fiber multifilament sample clamping device according to claim 1, characterized in that: The clamping surface is a frosted surface.

3. The double-sided carbon fiber multifilament sample clamping device according to claim 2, characterized in that: The diameter of the clamping surface is not less than the diameter of the sample.

4. The double-sided carbon fiber multifilament sample clamping device according to claim 1, characterized in that: The wedge-shaped surface is in an "eight" shape.

5. A double-sided carbon fiber multifilament sample clamping device according to any one of claims 1 to 4, characterized in that: The clamping assembly includes a first clamping block, wherein a set of opposite side surfaces of the first clamping block parallel to the sample are respectively provided with a first wedge surface and a first clamping surface; Another set of opposite side surfaces on the first clamping block that are parallel to the sample are planes.

6. A double-sided carbon fiber multifilament sample clamping device according to any one of claims 1 to 4, characterized in that: The clamping assembly includes a second clamping block, wherein a set of opposite side surfaces of the second clamping block parallel to the sample are respectively provided with a second wedge surface and a second clamping surface; Another set of opposite side surfaces on the second clamping block that are parallel to the sample are cutting surfaces.

7. The double-sided carbon fiber multifilament sample clamping device according to claim 6, characterized in that: The cut surfaces of the opposite sides of the second clamping block all face the sample.

8. A double-sided carbon fiber multifilament sample clamping device according to any one of claims 1 to 4, characterized in that: The clamping assembly includes a third clamping block, which in turn includes a clamping seat and a clamping head. A connecting structure is provided between the clamping seat and the clamping head, and the clamping head is detachably assembled on the clamping seat through the connecting structure. A third wedge-shaped surface is provided on one side of the clamping seat; A third clamping surface is provided on one side surface of the clamping head.

9. The double-sided carbon fiber multifilament sample clamping device according to claim 8, characterized in that: The connecting structure includes a slideway provided on the clamping seat and a slide groove provided on the clamping head, wherein the slideway is located on the opposite side of the third wedge surface, and the slide groove is located on the opposite side of the third clamping surface, and the slideway matches the slide groove; A pair of fastening screw holes is opened on one side surface of the slideway, and a pair of through holes is opened on one side surface of the slide groove, and the pair of fastening screw holes matches the pair of through holes; A pair of through holes are respectively inserted with fastening bolts that match a pair of fastening screw holes.

10. The double-sided carbon fiber multifilament sample clamping device according to claim 9, characterized in that: The cross sections of the slideway and the slide groove are both trapezoidal.

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