A kind of anti-surge clamp for ultra-high strength steel rod-like material tensile test
By designing upper and lower clamping block structures, combined with an integrated combination ring and limiting device, the problems of sample movement and easy damage to threaded connections in the testing of ultra-high strength steel bars by traditional clamps are solved, thus achieving both testing accuracy and clamp durability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- LINGYUN INDAL CORP
- Filing Date
- 2025-08-26
- Publication Date
- 2026-08-04
AI Technical Summary
Traditional tensile fixtures are prone to causing specimen movement in ultra-high strength steel bar tests, and the threaded connection structure is susceptible to fatigue failure, affecting test results and fixture life.
It adopts an upper and lower clamping block structure, and is fixed by an integrated combination ring. The upper clamping shaft and the upper shaft cap form a limiting device to adapt to different parts lengths and avoid fatigue damage caused by threaded connections.
It effectively prevents sample movement, improves the service life and adaptability of the fixture, ensures the accuracy of test results, reduces manual adjustment time, and is suitable for large-tonnage hydraulic tensile testing machines.
Smart Images
Figure CN224594334U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to a clamp, and more particularly to an anti-movement clamp for tensile testing of ultra-high strength steel rod-shaped materials. Background Technology
[0002] Whether the mechanical properties of metal bars meet the standards is determined by tensile testing, and the tensile fixture selected during the tensile test has a crucial influence. Traditionally, tensile testing machine fixtures used for bars are divided into two main types: threaded structure and stepped structure. The threaded structure has threaded connection holes on the clamping block body, and the two clamping blocks are connected by bolts. The opening reduces the strength of the clamping block body. Therefore, the stepped structure fixture is currently commonly used. Patent 201420168837.2 discloses a special fixture for tensile testing of metal bars. The fixture includes a fixture body (2), a specimen head window (2a), a specimen parallel section window (2b), a threaded hole (2c), and a countersunk hole (2d). The length of the specimen head window (2a) along the length direction of the fixture body is greater than the length of the specimen end (3a). The fixture also includes a connecting rod (1), one end of which is threaded to the fixture body, and the other end of which is connected to the testing machine. During the tensile test, the specimen head and the specimen head window are not completely fitted together, and the specimen is not in a completely fixed state. After the specimen is placed in the fixture body, when the tensile testing machine clamps the connecting rod 1, the wedge-shaped clamping block at the upper end of the testing machine generates a downward thrust, causing the connecting rod 1 to move the upper fixture body 2 downward, resulting in a gap between the upper transition area 3c of the specimen and the transition arc 2e of the fixture. Similarly, the wedge-shaped clamping block at the lower end of the testing machine generates an upward thrust, causing the connecting rod 1 to move the lower fixture body 2 upward, thus creating a gap between the lower transition area 3c of the specimen and the transition arc 2e of the fixture. If the tensile test is started directly under these conditions, the test curve will be abnormal, and the correct results cannot be obtained. Under this structure, before the test, the displacement of the testing machine needs to be manually adjusted to ensure that the upper and lower transition areas 3c of the specimen are in close contact with the upper and lower transition arcs 2e of the fixture before the tensile test can begin. The adjustment process is time-consuming and labor-intensive, and for large-tonnage hydraulic tensile testing machines used for testing ultra-high strength steel bars, manual adjustment is not allowed after the specimen is clamped. In addition, the connecting rod is threaded to the fixture body. During the tensile test, the threaded connection is prone to fatigue failure, which reduces the service life of the structural components. Moreover, it is an open structure, that is, an opening on one side of the fixture body. When the sample is pushed into the countersunk hole, the open structure greatly reduces the strength of the fixture body. Utility Model Content
[0003] To overcome the shortcomings of existing technologies, this utility model provides an anti-movement clamp for tensile testing of ultra-high strength steel rods. The clamping blocks consist of two interlocking pieces fixed by an integrated combination ring, resulting in no structural damage to the clamp body. The sample limiting device, composed of upper and lower clamping shafts and upper and lower shaft caps, can limit the position of the sample according to its location, making it highly applicable.
[0004] The technical solution adopted by this utility model to solve its technical problem is: An anti-movement clamp for tensile testing of ultra-high strength steel bars, the clamp comprising an upper clamping block structure and a lower clamping block structure with similar structures. The upper clamping block structure includes an upper clamping block, an upper clamping shaft, an upper shaft cap, and an upper combined ring. The upper clamping block includes two semi-circular clamping blocks, and a combined ring step is provided on the outer side of the lower end of each semi-circular clamping block. The upper combined ring is fitted onto the outer side of the two semi-circular clamping blocks whose end faces are in contact with the combined ring step. The interior of each semi-circular clamping block is provided with... The sample mounting area and the upper clamping shaft mounting area are connected from bottom to top. One end of the sample is clamped in the sample mounting area. The lower end of the upper clamping shaft is threadedly connected to the upper shaft cap and then clamped in the upper clamping shaft mounting area. The upper shaft cap contacts the end of the sample. The other end of the upper clamping shaft is connected to the wedge clamping end of the tensile testing machine. The sample mounting area and the lower clamping shaft mounting area in the lower clamping block structure are connected from top to bottom. The structure of the remaining components is the same as that of the upper clamping block structure.
[0005] The aforementioned anti-slip clamp for tensile testing of ultra-high strength steel bars comprises an upper clamping shaft mounting area including a lower cylindrical mounting area, a transition area, and an upper cylindrical mounting area. The diameter of the lower cylindrical mounting area is larger than the diameter of the upper cylindrical mounting area. The transition area is located between the two cylindrical mounting areas. The shape of the upper clamping shaft matches the shape of the upper clamping shaft mounting area. The upper clamping shaft is engaged inside the upper clamping shaft mounting area. The lower end of the upper clamping shaft is provided with an external thread, which is threadedly connected to the upper shaft cap. The upper shaft cap is engaged at the lower end of the lower cylindrical mounting area. Both the upper clamping shaft and the upper shaft cap are in smooth contact with the upper clamping shaft mounting area.
[0006] The aforementioned anti-movement clamp for tensile testing of ultra-high strength steel rods has a circular locking block at the upper end of the upper clamping shaft, which is engaged with the top of the upper clamping block.
[0007] The aforementioned anti-movement fixture for tensile testing of ultra-high strength steel rods includes a sample mounting area comprising an end mounting area and a middle rod mounting area. The diameter of the end mounting area is larger than the diameter of the middle rod mounting area. An arc-shaped transition area is provided between the two mounting areas. The shape and size of the sample mounting area match the sample.
[0008] The aforementioned anti-movement clamp for tensile testing of ultra-high strength steel rods has a smooth connection between the inner wall of the upper combined ring and the outer wall of the upper clamping block.
[0009] The beneficial effects of this utility model are: 1. The fixture of this utility model is provided with an upper clamping shaft and an upper shaft cap, which are threaded together to limit the movement of the sample. This can prevent the sample from moving vertically when clamped by a hydraulic testing machine and can be used on a hydraulic testing machine.
[0010] 2. The limiting structure formed by the upper clamping shaft and the upper shaft cap has an adjustable function, which can be adjusted within a certain range according to the length of the sample (by turning the upper shaft cap), and can adapt to the different sample lengths caused by the length tolerance in the actual sample processing.
[0011] 3. The clamping block and the combined ring are boltless, so there is no reduction in strength. Compared with the common bolted connection structure, the clamping block structure of the same size has lower working stress and longer service life. In addition, the combined ring is an integral structure, which is convenient and time-saving to install and improves the convenience of tooling use. 4. During the stretching process, the adjustable sample limiting structure is not subjected to force, the threaded part will not be damaged by fatigue, and the structure has a long service life and good reliability. Attached Figure Description
[0012] The present invention will be further described below with reference to the accompanying drawings.
[0013] Figure 1 This is a schematic diagram of the overall device structure of this utility model; Figure 2 for Figure 1 A partially enlarged structural diagram of section A in the middle; Figure 3 This is a schematic diagram of the semi-circular clamping block structure in the upper clamping block; Figure 4 This is a schematic diagram of the three-dimensional structure of the semi-circular clamping block in the upper clamping block; Figure 5 A schematic diagram of the structure after the end faces of the two semi-circular clamping blocks are fitted together; Figure 6 This is a schematic diagram of the structure where the upper combined ring is fitted onto the outside of the two semi-circular clamping blocks; Figure 7 This is a physical drawing of the overall device of this utility model.
[0014] In the diagram: 1. Upper clamping block; 1-1. Semi-circular clamping block; 1-2. Combined ring step; 1-3. Sample installation area; 1-3a. End installation area; 1-3b. Middle rod-shaped installation area; 1-3c. Arc-shaped transition area; 1-4. Upper clamping shaft installation area; 1-4a. Lower cylindrical installation area; 1-4b. Transition area; 1-4c. Upper cylindrical installation area; 2. Upper clamping shaft; 2-1. Circular clamping block; 3. Upper shaft cap; 4. Upper combined ring; 5. Sample. Detailed Implementation
[0015] The present invention will be further described below with reference to the accompanying drawings.
[0016] The technical terms “upper,” “lower,” “inner,” “outer,” “top,” and “bottom” used in this utility model to indicate orientation or positional relationships are based on the orientation or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the structure of this utility model.
[0017] See Figure 1 , Figure 2 , Figure 4 and Figure 5 This utility model discloses an anti-movement clamp for tensile testing of ultra-high strength steel rods, comprising an upper clamping block structure and a lower clamping block structure. A sample 5 is clamped between the upper and lower clamping block structures. The lower clamping block structure is similar to the upper clamping block structure. Taking the upper clamping block structure as an example, the upper clamping block structure includes an upper clamping block 1, an upper clamping shaft 2, an upper shaft cap 3, and an upper combined ring 4. The upper clamping block 1 includes two semi-circular clamping blocks 1-1. A combined ring step 1-2 is provided on the outer side of the lower end of each semi-circular clamping block 1-1. The upper combined ring 4 is sleeved on the outer side of the two semi-circular clamping blocks 1-1 whose end faces are in close contact. The lower end of the upper combined ring contacts the combined ring step 1-2. The sample 5, the upper clamping shaft 2, and the upper shaft cap 3 are all clamped between the two clamping blocks. In the cavity formed by the semi-circular clamping blocks, the upper clamping shaft is clamped at the top of the upper clamping block, and the lower end of the upper clamping shaft is threaded to the top of the upper shaft cap. The end 5-1 of the sample is in contact with the bottom end face of the upper shaft cap. The other end of the upper clamping shaft 2 is connected to the wedge clamping end of the tensile testing machine. The component composition of the lower clamping block structure is the same as that of the upper clamping block structure. The installation position of the lower combined ring and the lower clamping block is the same as that of the upper combined ring and the upper clamping block. The difference is that the clamping cavity in the middle of the lower clamping block and the clamping cavity in the middle of the upper clamping block are arranged symmetrically from top to bottom. That is, the clamping cavity of the lower clamping shaft is located at one end of the lower combined ring step, so that the clamping direction of the lower clamping shaft and the lower shaft cap is symmetrically arranged from top to bottom with the clamping direction of the upper clamping shaft 2 and the upper shaft cap 3.
[0018] See Figure 1 and Figure 3 The semi-circular clamping block 1-1 has a sample mounting area 1-3 and an upper clamping shaft mounting area 1-4 inside. The upper clamping shaft mounting area is located at the upper end of the upper clamping block, and the sample mounting area is located at the lower end of the upper clamping block. The two mounting areas are connected. The upper clamping shaft mounting area 1-4 includes, from bottom to top, a lower cylindrical mounting area 1-4a, a transition area 1-4b, and an upper cylindrical mounting area 1-4c. The diameter of the lower cylindrical mounting area 1-4a is larger than the diameter of the upper cylindrical mounting area 1-4c. The transition area 1-4b is located between the upper and lower cylindrical mounting areas. The shape of the upper clamping shaft 2 matches the shape of the upper clamping shaft mounting area 1-4, and the upper clamping shaft 2 engages with the sample mounting area 1-4. Inside the upper clamping shaft mounting area 1-4, the lower end of the upper clamping shaft 2 is provided with an external thread, which is threadedly connected to the upper shaft cap 3. The upper shaft cap 3 is snapped into the lower end of the lower cylindrical mounting area 1-4a. A circular locking block 2-1 is provided at the upper end of the upper clamping shaft 2. The circular locking block 2-1 is snapped into the top of the upper clamping block 1 to ensure the relative fixation of the upper clamping shaft and the upper clamping block, and to prevent the upper clamping shaft from shifting vertically. Both the upper clamping shaft 2 and the upper shaft cap 3 are in smooth contact with the upper clamping shaft mounting area 1-4. The upper shaft cap can be manually turned to rotate within the lower cylindrical mounting area to adjust the upper and lower position of the upper shaft cap so that it contacts the end of the sample, thereby playing a limiting role.
[0019] The sample mounting area 1-3 includes an end mounting area 1-3a and a middle rod-shaped mounting area 1-3b. The diameter of the end mounting area 1-3a is larger than the diameter of the middle rod-shaped mounting area 1-3b. An arc-shaped transition area 1-3c is provided between the two mounting areas. The shape and size of the sample mounting area 1-3 match the shape and size of the sample 5. The end 5-1 of the sample is snapped into the end mounting area, and the end of the middle rod-shaped structure is snapped into the middle rod-shaped mounting area.
[0020] Installation and usage process: During installation, install the lower clamping block structure first, and then install the upper clamping block structure.
[0021] a) First, screw the lower clamping shaft into the thread of the lower shaft cap. Then, install it together with the sample into a semi-circular clamping block. Observe the gap between the end face of the sample and the lower shaft cap. Tighten the lower shaft cap so that its end face is completely in contact with the end face of the sample. Then, fasten the other semi-circular clamping block. Finally, put the lower combination ring on the outside of the two semi-circular clamping blocks. The installation is complete. b) The installation method of the upper clamping block structure is the same as that of the lower clamping block structure; c) After both the upper and lower ends are installed, first clamp the lower clamping shaft onto the tensile test machine, then clamp the upper clamping shaft and begin the tensile test.
Claims
1. A clamp for preventing slippage in tensile testing of ultra-high strength steel rods, characterized in that: The clamp includes an upper clamping block structure and a lower clamping block structure with similar structures. The upper clamping block structure includes an upper clamping block (1), an upper clamping shaft (2), an upper shaft cap (3), and an upper combination ring (4). The upper clamping block (1) includes two semi-circular clamping blocks (1-1). A combination ring step (1-2) is provided on the outer side of the lower end of the semi-circular clamping block (1-1). The upper combination ring (4) is fitted on the outer side of the two semi-circular clamping blocks (1-1) with their end faces in contact with the combination ring step (1-2). The interior of the semi-circular clamping block (1-1) is provided with a continuous structure from bottom to top. The sample mounting area (1-3) and the upper clamping shaft mounting area (1-4) are connected. One end of the sample (5) is snapped into the sample mounting area (1-3). The lower end of the upper clamping shaft (2) is threadedly connected to the upper shaft cap (3) and then snapped into the upper clamping shaft mounting area (1-4). The upper shaft cap (3) is in contact with the end (5-1) of the sample (5). The other end of the upper clamping shaft (2) is connected to the wedge clamping end of the tensile testing machine. The sample mounting area and the lower clamping shaft mounting area in the lower clamping block structure are connected from top to bottom. The structure of the remaining components is the same as that of the upper clamping block structure.
2. The anti-movement clamp for tensile testing of ultra-high strength steel rods according to claim 1, characterized in that: The upper clamping shaft mounting area (1-4) includes a lower cylindrical mounting area (1-4a), a transition area (1-4b), and an upper cylindrical mounting area (1-4c). The diameter of the lower cylindrical mounting area (1-4a) is larger than the diameter of the upper cylindrical mounting area (1-4c). The transition area (1-4b) is located between the upper and lower cylindrical mounting areas. The shape of the upper clamping shaft (2) matches the shape of the upper clamping shaft mounting area (1-4). The upper clamping shaft (2) is engaged inside the upper clamping shaft mounting area (1-4). The lower end of the upper clamping shaft (2) is provided with an external thread and is threadedly connected to the upper shaft cap (3). The upper shaft cap (3) is engaged at the lower end of the lower cylindrical mounting area (1-4a). Both the upper clamping shaft (2) and the upper shaft cap (3) are in smooth contact with the upper clamping shaft mounting area (1-4).
3. The anti-movement clamp for tensile testing of ultra-high strength steel rods according to claim 2, characterized in that: The upper end of the upper clamping shaft (2) is provided with a circular locking block (2-1), which is engaged with the top of the upper clamping block (1).
4. The anti-movement clamp for tensile testing of ultra-high strength steel rods according to claim 1, characterized in that: The sample installation area (1-3) includes an end installation area (1-3a) and a middle rod-shaped installation area (1-3b). The diameter of the end installation area (1-3a) is larger than the diameter of the middle rod-shaped installation area (1-3b). An arc-shaped transition area (1-3c) is provided between the two installation areas. The shape and size of the sample installation area (1-3) match the sample (5).
5. The anti-movement clamp for tensile testing of ultra-high strength steel rods according to claim 1, characterized in that: The inner wall of the upper combined ring (4) is smoothly connected to the outer wall of the upper clamping block (1).