A clamping device for testing the tensile strength of a dog bone test block and a method of using the same

Abstract

The present invention provides a clamping device for testing the tensile strength of a dog-bone test block and a method for using the clamping device, wherein the clamping device for testing the tensile strength of a dog-bone test block comprises: a base, a clamping arm assembly and an adjusting jaw; by adjusting the clamping arm assembly and rotating the rotating inner rod in the adjusting jaw, the wedge plate slides radially to fit the variable diameter section of the dog-bone test block, and the load is transmitted from the adjustable arc-shaped clamp to the variable diameter section of the dog-bone test block. The present invention overcomes the problems of stress concentration caused by insufficient contact between the clamping mechanism and the variable diameter section of the dog-bone test block, crack development outside the observation area, and excessive discreteness caused by frequent replacement of the clamping mechanism during testing of dog-bone test blocks of different sizes, and has a simple structure, high versatility, and simple and convenient operation.

Description

Technical Field

[0001] The invention relates to a device for detecting tensile strength, and in particular to a clamping device for detecting tensile strength of a dog bone test block and a use method thereof. Background Art

[0002] Tensile strength is the critical value of the material's transition from uniform plastic deformation to local concentrated plastic deformation, that is, the resistance to the maximum uniform plastic deformation of the material, which reflects the material's fracture resistance. Therefore, it is necessary to test the tensile strength of the material. There are many shapes of material specimens for tensile strength tests, mainly dog-bone, cylinder, prism, etc.

[0003] The shape and size of the dog bone specimen have a great influence on the success rate of the test. my country currently does not have a unified relevant standard. Foreign countries currently only give the shape but not the specific size in some guidelines. The inconsistency of these guidelines also affects the success rate of the test.

[0004] Domestic and foreign scholars have conducted relevant research on the direct pull test of dog-bone specimen materials. However, the variable diameter section of the dog-bone test is prone to cause stress concentration due to insufficient contact of the clamps. The crack initiation point is not in the equal-section detection area, and the test fails.

[0005] In order to solve the above problems, the present invention provides a clamping device for detecting the tensile strength of a dog-bone test block and a method for using the same. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a clamping device which has high adaptability to dog-bone specimen materials of various sizes, solves the stress concentration problem that may be caused by insufficient contact, and ensures the stability of the material during the tensile test.

[0007] As for the clamping device used for testing the tensile strength of dog bone sample materials, the testing device of the present invention for solving the above technical problems adopts the following technical solutions:

[0008] A device for testing the tensile strength of dog-bone specimen materials, comprising a first clamping mechanism and a second clamping mechanism respectively disposed at two ends of a dog-bone specimen and used to clamp the dog-bone specimen, wherein the first clamping mechanism and the second clamping mechanism have the same structure. The first clamping mechanism comprises a base, a clamping arm assembly and an adjusting clamping jaw, wherein the clamping arm assembly comprises a first clamping arm, a second clamping arm and a limiting assembly, wherein one end of the first clamping arm is hinged to the base, and one end of the second clamping arm is hinged to the base, and the first clamping arm and the second clamping arm are arranged opposite to each other to form an adjusting arm;

[0009] The limiting component is used to limit the size of a clamping angle formed between the first clamping arm and the second clamping arm.

[0010] The adjusting jaw comprises a first adjusting jaw arranged on the first clamping arm and a second adjusting jaw arranged on the second clamping arm, and the first adjusting jaw and the second adjusting jaw cooperate with each other to clamp the dog-bone test block.

[0011] The first clamping mechanism of the present invention is a clamping device that clamps the dog-bone test block by combining a clamping arm and an adjusting clamping jaw and fixing the dog-bone test block through a limit assembly. For the detection of the tensile strength of materials with a structure such as the dog-bone test block, the present invention can fully and stably contact the dog-bone test block, thereby reducing the error in the tensile strength detection of the dog-bone test block.

[0012] Further, the first clamping arm includes a first left swing arm, a first right swing arm and a first connecting plate;

[0013] The first left swing arm and the first right swing arm are respectively hinged to the base, and the first connecting plate is used to connect the first left swing arm and the first right swing arm.

[0014] The first connecting plate has two functions: the first is to increase the overall stiffness of the first clamping arm so that the device is more evenly stressed; the second is to enable the first left swing arm and the first right swing arm to rotate synchronously to avoid eccentric stress caused by misalignment of the device.

[0015] Further, the second clamping arm includes a second left swing arm, a second right swing arm and a second connecting plate;

[0016] The second left swing arm and the second right swing arm are respectively hinged to the base, and the second connecting plate is used to connect the second left swing arm and the second right swing arm.

[0017] The second connecting plate has two functions: the first is to increase the overall stiffness of the second clamping arm so that the force on the device is more uniform; the second is to enable the second left swing arm and the second right swing arm to rotate synchronously to avoid eccentric force caused by misalignment of the device.

[0018] Furthermore, the limiting component includes a first limiter and a second limiter.

[0019] The first limiter comprises a first front mounting seat, a first rear mounting seat, a first connecting rod, a first front regulating valve and a first rear regulating valve, wherein the first front mounting seat is mounted on the first left swing arm, the first rear mounting seat is mounted on the second left swing arm, the first end of the first connecting rod passes through the first front mounting seat, the second end of the first connecting rod passes through the first rear mounting seat, the first front regulating valve is sleeved on the first end of the first connecting rod, the first rear regulating valve is sleeved on the second end of the first connecting rod, and the clamping angle between the first clamp arm and the second clamp arm is limited by rotating the first front regulating valve and / or the first rear regulating valve;

[0020] The second limiter includes a second front mounting seat, a second rear mounting seat, a second connecting rod, a second front regulating valve and a second rear regulating valve. The second front mounting seat is mounted on the first right swing arm, and the second rear mounting seat is mounted on the second right swing arm. The first end of the second connecting rod passes through the second front mounting seat, and the second end of the second connecting rod passes through the second rear mounting seat. The second front regulating valve is sleeved on the first end of the second connecting rod, and the second rear regulating valve is sleeved on the second end of the second connecting rod. The clamping angle between the first clamp arm and the second clamp arm is limited by rotating the second front regulating valve and / or the second rear regulating valve.

[0021] The limiting assembly in the present invention can adjust the angle between the first clamp arm and the second clamp arm so as to adapt to dog bone test blocks of different sizes and play a fixing role. The specific operation of the limiting assembly is as follows:

[0022] One end of the dog bone test block is placed in the first clamping mechanism, the first clamping arm and the second clamping arm are adjusted to form a first clamping angle, the first connecting rod and the second connecting rod are installed to preliminarily fix the first clamping angle, the first adjusting jaw and the second adjusting jaw are adjusted, the first clamping arm and the second clamping arm further form a second clamping angle, and the first front regulating valve and / or the first rear regulating valve, the second front regulating valve and / or the second rear regulating valve are adjusted to fix the second clamping angle.

[0023] Further, the first adjusting clamping jaw comprises a first rotating inner rod and a first arc-shaped clamping head;

[0024] One end of the first rotating inner rod is rotatably connected to the first left swing arm, and the other end is rotatably connected to the first right swing arm. The end surface of one end of the first rotating inner rod is provided with a first stopper, and the other end is sleeved with a first limit valve. A first cam is fixedly sleeved on the first rotating inner rod, and the first cam is located between the first left swing arm and the first right swing arm.

[0025] The first arc-shaped chuck is rotatably sleeved on the outer surface of the first cam, and the first cam is driven to rotate by rotating the first rotating inner rod, so as to adjust the arc-shaped contact surface between the first arc-shaped chuck and the dog-bone test block variable diameter section.

[0026] In the technical solution, the first cam is sleeved on the first rotating inner rod, and the first cam is driven to rotate by rotating the first rotating inner rod, so that the first cam can be rotated more conveniently, thereby better adjusting the first adjusting jaw.

[0027] Furthermore, the first arc-shaped chuck includes a first clamping sleeve and a first arc-shaped block, the first clamping sleeve is rotatably sleeved on the first cam, the first clamping sleeve is provided with a first mounting groove for installing the first arc-shaped block, and a first limiting clamping device is respectively provided between the two sides of the first arc-shaped block and the first clamping sleeve that surrounds the first mounting groove.

[0028] In the technical solution, the first mounting groove can well assemble the first ferrule and the first arc block into an arc chuck, and the first limiting clamping device can make the first ferrule and the first arc block fit better.

[0029] Further, the first arc block includes a first wedge plate and second wedge plates respectively located on both sides of the first wedge plate;

[0030] A second limiting and clamping device is respectively provided between each of the second wedge plates and the first wedge plates, and the second limiting and clamping device further includes a first limiting groove provided on the first wedge block, and a first limiting protrusion provided on the second wedge plate, the free end of the first limiting protrusion is located in the first limiting groove, and a plurality of first placement grooves are provided on the first limiting protrusion, and a compression spring is built in each of the first placement grooves.

[0031] In the technical solution, a compression spring is built into each placement groove to better change and stabilize the arc-shaped contact surface formed by the first wedge block and the second wedge block.

[0032] Furthermore, when the first arc-shaped chuck is in a tightened state, a center line of the first arc-shaped block passes through a center of the first cam.

[0033] Furthermore, during the rotation of the first rotating inner rod, the outer curvature of the first arc-shaped chuck changes, and the center line of the first arc-shaped block passes through the center of the first cam.

[0034] Furthermore, the first limiting and clamping device includes second limiting grooves arranged on both sides of the first arc block, and second limiting protrusions arranged on both sides of the first clamping sleeve, the free end of each second limiting protrusion is respectively located in each second limiting groove, and each second limiting protrusion is provided with a plurality of second placement grooves, and each of the second placement grooves has a built-in compression spring.

[0035] In the present technical solution, the second limiting protrusion and the second limiting groove can make the assembly effect of the first arc block and the first sleeve better. The second placement groove has a built-in compression spring to provide resistance to the external load pressure. When the arc contact surface of the first arc block composed of the first wedge block and the second wedge block changes, the positional relationship between the wedge block and the second wedge block can be better stabilized.

[0036] Furthermore, a plurality of third placement grooves are respectively provided on both sides of the first ferrule, and a compression spring is built into each of the third placement grooves.

[0037] Furthermore, a plurality of fourth placement grooves are respectively provided on both sides of the first wedge-shaped plate, and a compression spring is built in each of the fourth placement grooves.

[0038] Compared with the prior art, the above-mentioned features of the present invention enable the first clamping mechanism to adjust and adapt to dog-bone test blocks of different sizes, better fit the curved surface of the dog-bone test block, and reduce the problem of stress concentration.

[0039] Furthermore, a clamping rod and a thread on the clamping rod are provided at the center of the upper portion of the base to increase friction and contact area, which is beneficial to the stability of the device load holding; a symmetrical rotating shaft is arranged in the middle of the base so that the clamping arms can rotate axially and adjust the distance between the clamping arms.

[0040] The clamping device for tensile strength testing of dog-bone test blocks of the present invention adopts the above structure. Since the adjusting jaws can adjust the outer curvature of the arc block according to the curvature of the dog-bone test block, it can be completely fitted with the contact surface of the variable diameter section of the dog-bone test block, thereby reducing the problem of stress concentration caused by insufficient contact between the clamping device and the dog-bone test block. In addition, since the limiting component adopts a pair of limiters, the entire device is balanced, thereby further improving the stability of the dog-bone test block during the tensile strength testing process.

[0041] A method for using a clamping device for testing the tensile strength of a dog bone test block comprises the following steps:

[0042] The bases in the first clamping mechanism and the second clamping mechanism are respectively fixed by using the chuck of a universal testing machine, and the first clamping mechanism and the second clamping mechanism are symmetrically arranged;

[0043] Placing two ends of the dog-bone test block in the first clamping mechanism and the second clamping mechanism respectively, and adjusting the first clamping mechanism and the second clamping mechanism respectively to clamp the dog-bone test block, wherein the first clamping mechanism and the second clamping mechanism are used in the same manner;

[0044] The method for using the first clamping mechanism further comprises the following steps:

[0045] Rotate the first clamp arm and the second clamp arm to contact the detection part of the dog bone test block, and adjust the first limiter and the second limiter to initially fix the first clamp angle formed between the first clamp arm and the second clamp arm;

[0046] The universal testing machine is adjusted so that the arc-shaped chuck contacts the dog-bone test block, the first adjustment jaw and the second adjustment jaw are adjusted to completely fit the variable diameter area of ​​the dog-bone test block, and then the first adjustment jaw and the second adjustment jaw are fixed, and the first limiter and the second limiter are further adjusted to fix the second clamping angle formed between the first clamp arm and the second clamp arm.

[0047] Compared with the prior art, the technical solution proposed in this application has the following beneficial effects:

[0048] Since the dog-bone test block has a variable diameter section, it is easy to cause stress concentration due to insufficient contact between the clamping mechanism and the variable diameter section of the dog-bone test block. The adjusting jaw in the present technical solution can be adjusted to have an arc-shaped contact surface that fits the variable diameter section of the dog-bone test block, thereby solving the stress concentration problem caused by insufficient contact between the clamping mechanism and the variable diameter section of the dog-bone test block. At the same time, the clamp arm assembly in the present solution can adapt to dog-bone test blocks of different sizes by adjusting the clamping angles of the first clamp arm and the second clamp arm used to clamp the dog-bone test block. The present technical solution has a simple structure. At the same time, it is easy to operate and does not require complicated procedures. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0050] Figure 1 The three-dimensional combination of the clamping device and the dog bone test block of the present invention Figure 3 Dimensional structure diagram.

[0051] Figure 2 It is a schematic diagram of a three-dimensional view of the base in the clamping device of the present invention.

[0052] Figure 3 It is a schematic perspective view of the first clamping arm in the clamping device of the present invention.

[0053] Figure 4 A schematic diagram of a three-dimensional view of the second clamping arm in the clamping device of the present invention

[0054] Figure 5 This is a schematic diagram of a three-dimensional view of the first limiter in the clamping device.

[0055] Figure 6 This is a schematic diagram of a three-dimensional view of the second limiter in the clamping device.

[0056] Figure 7 This is a schematic diagram of a three-dimensional view of the exploded first adjusting clamping jaw in the clamping device.

[0057] Figure 8 It is a schematic three-dimensional diagram of the first wedge plate and the second wedge plate in the clamping device of the present invention.

[0058] Fig. 9 It is a cross-sectional view of the first adjusting clamping jaw in the clamping device of the present invention in the retracted state.

[0059] Fig.10 It is a cross-sectional view of the first adjusting clamping jaw in the clamping device of the present invention in the expanded state.

[0060] In the figure: 1, base; 2, first clamping arm; 3, first adjusting jaw; 4, second clamping arm; 5, second adjusting jaw; 6, first stopper; 7, first rotating rod; 8, second rotating rod; 9, second stopper; 10, dog bone test block; 11, clamping rod; 21, first right swing arm; 22, first connecting plate; 23, first left swing arm; 61, first rear regulating valve; 62, first front regulating valve; 63, first rear mounting seat; 64, first front mounting seat; 65, first connecting rod; 131, first shaft connecting hole; 132, second shaft connecting hole; 210, second connecting hole; 230, first connecting hole; 410, third connecting hole; 430, fourth connecting hole; 41, second left swing arm; 42, first connecting plate; 43, second right swing arm; 94, second front mounting seat; 93, second rear mounting seat; 9 2. Second front regulating valve; 91. Second rear regulating valve; 95. Second connecting rod; 231. First middle connecting hole; 411. Third middle connecting hole; 431. Fourth middle connecting hole; 232. First hole; 212. Second hole; 30. First arc chuck; 34. First rotating inner rod; 341. First baffle plate; 342. First limit valve; 340. First cam; 33. First ferrule; 300. First arc block; 333. First mounting groove; 35. First limit clamping device; 314. Second limit groove; 330. Second limit protrusion; 331. Second placement groove; 32. First wedge plate; 31. Second wedge plate; 36. Second clamping device; 321. First limit groove; 313. First limit protrusion; 311. First placement groove; 332. Third placement groove; 312. Fourth placement groove. DETAILED DESCRIPTION

[0061] In order to make the purpose, technical scheme and advantages of the present invention clearer, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, it can be understood by those skilled in the art that in the embodiments of the present invention, many technical details are provided to enable readers to better understand the present application. However, even without these technical details and various changes and modifications based on the following embodiments, the technical scheme protected by each claim of the present application can be implemented.

[0062] In order to better illustrate the present invention, the following Figure 1-10 The present invention is described in detail.

[0063] Embodiment 1

[0064] See also Figure 1As shown, the present invention provides a clamping device for tensile strength testing of a dog-bone test block, comprising a first clamping mechanism and a second clamping mechanism of the same structure for clamping the dog-bone test block, wherein the first clamping mechanism comprises a base 1, a first clamping arm 2 and a second clamping arm 4 of the same structure, and a first adjustment jaw 3 and a second adjustment jaw 5 of the same structure. It is worth mentioning that the first clamping arm 2 and the second clamping arm 4 may not be limited to completely the same structure, and the first adjustment jaw 3 and the second adjustment jaw 5 may not be limited to completely the same structure.

[0065] In the specific example of this embodiment, a clamping rod 11 with threads is fixed at the center of the upper part of the base 1. The threads on the clamping rod 11 increase the friction and contact area between the clamping rod 11 and the chuck of the microcomputer-controlled electronic universal testing machine, which is conducive to the stability of the device. Figure 2 As shown, specifically, a symmetrical first rotation axis connection hole 131 and a second rotation axis connection hole 132 are provided in the middle of the base, the radius of the first rotation axis connection hole 131 is the same as the radius of the first rotation rod 7, and the radius of the second rotation axis connection hole 132 is the same as the radius of the second rotation rod 8, so that the first clamp arm 2 makes an axial movement through the first rotation rod 7 and the second clamp arm 4 makes an axial rotation through the second rotation rod 8, thereby further adjusting the clamping angle between the first clamp arm 2 and the second clamp arm 4. It should be noted that in this embodiment, the way in which the first clamp arm 2 and the second clamp arm 4 are connected to the base 1 is not limited to the above-mentioned way, and the structures that can make the first clamp arm 2 and the second clamp arm 4 swing relative to the base 1 are all within the protection scope of the present invention.

[0066] In addition, the first clamping arm 2 includes a first left swing arm 23, a first right swing arm 21 and a first connecting plate 22 of the same structure. Figure 3 As shown, specifically, the upper end of the first left swing arm 23 is provided with a first connection hole 230 connected to one end of the first rotating rod 7, and the upper end of the first right swing arm 21 is provided with a second connection hole 210 connected to the other end of the first rotating rod 7. The radius of the first connection hole 230 is the same as the radius of the first rotating rod 7, and the radius of the second connection hole 210 is the same as the radius of the first rotating rod 7. The first connecting plate 22 is used to connect the first left swing arm 23 and the first right swing arm 21. The first connecting plate 22 can not only increase the overall rigidity of the first clamp arm 2, so that the device is evenly stressed, but also make the first left swing arm 23 and the first right swing arm 21 rotate synchronously to avoid eccentric stress caused by device misalignment. See. Figure 1-3As shown, specifically, the first left swing arm 23 and the first right swing arm 21 are respectively arranged on both sides of the base 1, the first rotating rod 7 connects the first left swing arm 23, the base 1 and the first right swing arm 21, and the first left swing arm 23 and the first right swing arm 21 can swing synchronously relative to the base 1. It should be noted that the technical solution of the present invention does not limit the connection structure of the first left swing arm 23 and the first right swing arm 21 and the base 1, and the structure that enables the first clamping arm 2 to swing relative to the base 1 is within the protection scope of the technical solution of the present invention.

[0067] The second clamping arm 4 comprises a second left swing arm 41, a second right swing arm 43 and a second connecting plate 42 of the same structure. Figure 4 As shown, specifically, the upper end of the second left swing arm 41 is provided with a third connecting hole 410 connected to one end of the second rotating rod 8, and the upper end of the second right swing arm 43 is provided with a fourth connecting hole 430 connected to the other end of the second rotating rod 8. The radius of the third connecting hole 410 is the same as the radius of the second rotating rod 8, and the radius of the fourth connecting hole 430 is the same as the radius of the second rotating rod 8. The second connecting plate 42 is used to connect the second left swing arm 41 and the second right swing arm 43. The second connecting plate 42 can not only increase the overall rigidity of the second clamping arm 4, so that the device is evenly stressed, but also enable the second left swing arm 41 and the second right swing arm 43 to rotate synchronously, avoiding eccentric stress caused by device misalignment. Figure 1 , 2 4, specifically, the second left swing arm 41 and the second right swing arm 43 are respectively arranged on both sides of the base 1, and the second left swing arm 41 and the second right swing arm 43 can swing synchronously relative to the base 1. It should be noted that the structures of the second left swing arm 41 and the second right swing arm 43 and the base 1 that enable the second clamping arm 4 to swing relative to the base 1 are all within the protection scope of the present invention.

[0068] In this embodiment, since the first clamping mechanism of the clamping device for the tensile strength test of the dog-bone test block includes the first adjustment jaw 3 and the second adjustment jaw 5 for clamping the dog-bone test block, in actual application, the user can adjust the first adjustment jaw 3 and the second adjustment jaw 5 to make the first clamping mechanism of the clamping device for the tensile strength test of the dog-bone test block better clamp the first end of the dog-bone test block, and the use is simple and convenient. In addition, a limiting component is provided on the first clamping mechanism, referring to Figure 1 As shown, specifically, the limit assembly includes a first limiter 6 and a second limiter 9 of the same structure, so that the first clamping mechanism of the clamping device for the tensile strength test of the dog-bone test block can clamp the first end of the dog-bone test block more stably.

[0069] Reference Figure 5As shown, a specific example of this embodiment, the first limiter 6 includes a first front mounting seat 64, a first rear mounting seat 63, a first connecting rod 65, a first front regulating valve 62 and a first rear regulating valve 61, the first front mounting seat 64 is mounted on the first left swing arm 23, the first rear mounting seat 222 is mounted on the second left swing arm 41, the first end of the first connecting rod 65 passes through the first front mounting seat 64, the second end of the first connecting rod 65 passes through the first rear mounting seat 63, the first front regulating valve 62 is sleeved on the first end of the first connecting rod 65, the first rear regulating valve 61 is sleeved on the second end of the first connecting rod 65, and the clamping angle between the first clamp arm 2 and the second clamp arm 4 is limited by rotating the first front regulating valve 62 and / or the first rear regulating valve 61.

[0070] Reference Figure 6 As shown, a specific example of this embodiment, the second limiter 9 includes a second front mounting seat 94, a second rear mounting seat 93, a second connecting rod 95, a second front regulating valve 92 and a second rear regulating valve 91, the second front mounting seat 94 is mounted on the first right swing arm 21, the second rear mounting seat 93 is mounted on the second right swing arm 43, the first end of the second connecting rod 95 passes through the second front mounting seat 94, the second end of the second connecting rod 95 passes through the second rear mounting seat 93, the second front regulating valve 92 is sleeved on the first end of the second connecting rod 95, the second rear regulating valve 91 is sleeved on the second end of the second connecting rod 95, and the clamping angle between the first clamp arm 2 and the second clamp arm 4 is limited by rotating the second front regulating valve 92 and / or the second rear regulating valve 91.

[0071] Specifically, the first front mounting seat 64 and the second front mounting seat 94 are at the same horizontal position as a whole crossbar, the first end is connected to the first middle connecting hole 231 on the first left swing arm 23, and the second end is connected to the second middle connecting hole 211 on the first right swing arm 21, and the radius of the first middle connecting hole 231 and the second middle connecting hole 211 is the same as the radius of the crossbar. The first rear mounting seat 63 and the second rear mounting seat 93 are at the same horizontal position as a whole crossbar, the first end is connected to the third middle connecting hole 411 on the second left swing arm 41, and the second end is connected to the fourth middle connecting hole 431 on the second right swing arm 43, and the radius of the third middle connecting hole 411 and the fourth middle connecting hole 431 is the same as the radius of the crossbar. This ensures that the first connecting rod 65 and the second connecting rod 95 always remain horizontal when the first clamp arm 2 and the second clamp arm 4 rotate.

[0072] The limit assembly of this embodiment is not limited to the structure described above. Any limit assembly that can keep the first clamping arm 2 and the second clamping arm 4 fixed when adjusted to a required clamping angle and does not affect the tensile strength test is within the protection scope of the present invention.

[0073] In addition, the first adjusting jaw 3 in the present embodiment includes a first rotating inner rod 34 and a first arc-shaped chuck 30, one end of the first rotating inner rod 34 is rotatably connected to the first left swing arm 23 through the first hole 232 on the first left swing arm 23, and the other end is rotatably connected to the first right swing arm 21 through the second hole 212 on the first right swing arm 21, the end surface of one end of the first rotating inner rod 34 is provided with a first baffle 341, and the other end is a first limit valve 342, the first rotating inner rod 34 is fixedly sleeved with a first cam 340, and the first cam 340 is located between the first left swing arm 23 and the first right swing arm 21, the first arc-shaped chuck 30 includes a first clamping sleeve 33 and a first arc block 300, the first clamping sleeve 33 is rotatably sleeved on the first cam 340, the first clamping sleeve 33 is provided with a first mounting groove 333 for installing the first arc block 300, and a first limit clamping device 35 is provided between the first clamping sleeves 33 on both sides of the first arc block.

[0074] See also Figure 7-10 As shown, in a specific example of this embodiment, the variable diameter length of the first cam 340 includes R3, R2 and R1, and R3>R2>R1. The first arc chuck is rotatably sleeved on the outer surface of the first cam 340, and the first cam 340 is driven to rotate by rotating the first rotating inner rod 34, so as to adjust the arc contact surface between the first arc chuck 30 and the dog bone test block. When the first arc chuck 30 is in a tightened state, the center line of the first arc block 300 passes through the center of the first cam 340. During the rotation of the first rotating inner rod 34, the outer curvature of the first arc block 300 changes, thereby keeping the center line of the first arc block 300 passing through the center of the first cam 340. It is worth mentioning that the diameter length of the variable diameter section of the first cam 340 is not limited to R3, R2 and R1, and increasing the variable diameter length or reducing the number of variable diameter lengths is also within the protection scope of the present invention.

[0075] Specifically, the first limiting and clamping device 35 includes a second limiting groove 314 arranged on both sides of the first arc block 300, and a second limiting protrusion 330 arranged on both sides of the first clamping sleeve 33. The free end of each second limiting protrusion 330 is respectively located in the second limiting groove 314 on each first wedge plate, and each second limiting protrusion 330 is provided with a plurality of second placement grooves 331, and each second placement groove has a built-in clamping spring.

[0076] In addition, the first arc block 300 includes a first wedge plate 32 and second wedge plates 31 respectively located on both sides of the first wedge plate. A second clamping device 36 is respectively provided between the second wedge plate 31 and the first wedge plate 32, and the second clamping device 36 further includes a first limiting groove 321 provided on the first wedge plate 32, and a first limiting protrusion 313 provided on the second wedge plate, the free end of the first limiting protrusion 313 is located in the first limiting groove 321, and each first limiting protrusion 313 is provided with a plurality of first placement grooves 311, each first placement groove has a built-in clamping spring, and the free end of each first limiting protrusion 313 is respectively located in each first limiting groove 321. In addition, increasing or decreasing the number of the first wedge plate and / or the second wedge plate is also within the protection scope of the present invention.

[0077] Specifically, a plurality of third placement grooves 332 are respectively provided on both sides of the first ferrule 33, and each of the third placement grooves 332 has a built-in compression spring. A plurality of fourth placement grooves 312 are respectively provided on both sides of the first wedge plate 32, and each of the fourth placement grooves 312 has a built-in compression spring. During the rotation 34 of the first rotating inner rod, the first arc block 300 moves radially along the first cam 340, and the outer curvature of the first arc chuck 30 changes. When the outer curvature is completely in contact with the transition zone of the dog bone reducing section, the first rotating inner rod 34 is stopped from rotating, and any of the compression springs is relaxed. It should be noted that the position form of the placement grooves and the compression springs is not limited to the above fixing method, and the method that can achieve the above purpose is also within the protection scope of the present invention.

[0078] In a specific example of this embodiment, the second adjustment jaw 5 is located on the second clamping arm 4 and has the same structure as the first adjustment jaw 3. The connection method and working principle between the second adjustment jaw 5 and the second clamping arm 4 are the same as the connection method and working principle between the first adjustment jaw 3 and the first clamping arm 2. Therefore, the second adjustment jaw 5 will not be described.

[0079] In the specific example of this embodiment, the first clamping mechanism has the same structure as the second clamping mechanism and clamps the other end of the dog-bone test block in the same working mode as the first clamping mechanism, so the second clamping mechanism will not be described again.

[0080] Embodiment 2

[0081] This embodiment is a method for using a clamping device for testing the tensile strength of a dog bone test block based on the first embodiment, comprising the following steps:

[0082] The bases in the first clamping mechanism and the second clamping mechanism are respectively fixed by using the chuck of a universal testing machine, and the first clamping mechanism and the second clamping mechanism are symmetrically arranged.

[0083] The two ends of the dog-bone test block are respectively placed in the first clamping mechanism and the second clamping mechanism, and the first clamping mechanism and the second clamping mechanism are respectively adjusted to clamp the dog-bone test block, wherein the first clamping mechanism and the second clamping mechanism are used in the same manner.

[0084] The method for using the first clamping mechanism further comprises the following steps:

[0085] The first clamp arm 2 and the second clamp arm 4 are rotated to contact the first end detection part of the dog bone test block 10, and the first stopper 6 and the second stopper 9 are preliminarily adjusted to preliminarily fix the first end of the dog bone test block 10. The preliminarily use method of the first stopper 6 and the second stopper 9 is the same.

[0086] The preliminary method of using the first stopper 6 further comprises the following steps:

[0087] When the first clamp arm 2 and the second clamp arm 4 are in contact with the first end detection portion of the dog bone test block 10, a fixed first clamping angle is formed between the first clamp arm 2 and the second clamp arm 4, and the first connecting rod 65 and the second connecting rod 95 are installed to preliminarily fix the first clamping angle between the first clamp arm 2 and the second clamp arm 4.

[0088] Since the preliminary adjustment method of the second stopper 9 is the same as the preliminary adjustment method of the first stopper 6 , the preliminary adjustment method of the second stopper 9 will not be described further.

[0089] The chuck of the electronic universal testing machine is adjusted to make the first adjustment jaw 3 contact with the diameter reducing section on one side of the first end of the dog-bone test block 10, and the first rotating inner rod 34 is rotated. When the first adjustment jaw 3 is completely fitted with the diameter reducing section on one side of the first end of the dog-bone test block 10, the first rotating inner rod 34 is stopped from rotating. At the same time, the second adjustment jaw 5 is completely fitted with the diameter reducing section on the other side of the first end of the dog-bone test block 10 in the same way, and the first stopper 6 and the second stopper 9 are further adjusted to fix the first end of the dog-bone test block 10. The further use methods of the first stopper 6 and the second stopper 9 are the same.

[0090] A further method of using the first stopper 6 comprises the following steps:

[0091] When the first adjustment jaw 3 and the second adjustment jaw 5 are completely fitted with the variable diameter section at the first end of the dog bone test block 10, a fixed second clamping angle is formed between the first clamping arm 2 and the second clamping arm 4, and the first front limit valve 62 and / or the first rear limit valve 61 are adjusted to fix the second clamping angle between the first clamping arm 2 and the second clamping arm 4 at this time.

[0092] Since the further adjustment method of the second limiter 9 is the same as the further adjustment method of the first limiter 6 , the further adjustment method of the second limiter 9 will not be described herein.

[0093] Since the second clamping mechanism has the same structure and usage as the first clamping mechanism, the adjustment method of the two clamping mechanisms will not be described here.

[0094] It is not difficult to find that this embodiment is a system embodiment corresponding to the first embodiment, and this embodiment can be implemented in conjunction with the first embodiment. The relevant technical details mentioned in the first embodiment are still valid in this embodiment, and in order to reduce repetition, they are not repeated here. Accordingly, the relevant technical details mentioned in this embodiment can also be applied to the first embodiment.

[0095] Those skilled in the art will appreciate that the above-mentioned embodiments are specific examples for implementing the present invention, and in actual applications, various changes may be made thereto in form and detail without departing from the spirit and scope of the present invention.

Claims

1. A clamping device for testing the tensile strength of a dog bone test block, characterized in that: It comprises a first clamping mechanism and a second clamping mechanism respectively disposed at two ends of the dog-bone test block and used for clamping the dog-bone test block, wherein the first clamping mechanism and the second clamping mechanism have the same structure; The first clamping mechanism includes a base, a clamping arm assembly and an adjusting clamping jaw; The clamp arm assembly includes a first clamp arm, a second clamp arm and a limiting assembly; One end of the first clamp arm is hinged to the base, one end of the second clamp arm is hinged to the base, and the first clamp arm and the second clamp arm are arranged opposite to each other to form a first adjustment arm; The first clamping arm comprises a first left swing arm, a first right swing arm and a first connecting plate, wherein the first connecting plate is used to connect the first left swing arm and the first right swing arm; The limiting component is used to limit the size of the clamping angle formed between the first clamping arm and the second clamping arm; the limiting component includes a first limiter and a second limiter; The adjusting jaw comprises a first adjusting jaw provided on the first clamping arm and a second adjusting jaw provided on the second clamping arm, and the first adjusting jaw cooperates with the second adjusting jaw to clamp the dog bone test block; The first adjusting clamp comprises a first rotating inner rod and a first arc-shaped clamp; one end of the first rotating inner rod is rotatably connected to the first left swing arm, and the other end is rotatably connected to the first right swing arm, a first cam is fixedly sleeved on the first rotating inner rod, and the first cam is located between the first left swing arm and the first right swing arm; The first arc-shaped chuck is rotatably sleeved on the outer surface of the first cam, and the first cam is driven to rotate by rotating the first rotating inner rod, so as to adjust the arc-shaped contact surface between the first arc-shaped chuck and the dog-bone test block; The first arc-shaped chuck comprises a first clamping sleeve and a first arc-shaped block, the first clamping sleeve is rotatably sleeved on the first cam, the first clamping sleeve is provided with a first mounting groove for mounting the first arc-shaped block, and a first limiting and pressing device is respectively provided between the two sides of the first arc-shaped block and the first clamping sleeve surrounding the first mounting groove; The first arc block includes a first wedge plate and a second wedge plate respectively located on both sides of the first wedge plate; A second limiting and pressing device is respectively provided between each of the second wedge-shaped plates and the first wedge-shaped plates, the second limiting and pressing device comprises a first limiting groove provided on the first wedge-shaped plate and a first limiting protrusion provided on the second wedge-shaped plate, the free end of the first limiting protrusion is located in the first limiting groove, and a plurality of first placement grooves are provided on the first limiting protrusion, and each of the first placement grooves has a built-in pressing spring; When the first arc-shaped chuck is in a tightened state, the center line of the first arc-shaped block passes through the center of the first cam; During the rotation of the first rotating inner rod, the outer curvature of the first arc-shaped chuck changes, and the center line of the first arc-shaped block passes through the center of the first cam.

2. The clamping device for dog bone test block tensile strength testing according to claim 1, characterized in that: The first left swing arm and the first right swing arm are respectively hinged to the base; The second clamping arm includes a second left swing arm, a second right swing arm and a second connecting plate; The second left swing arm and the second right swing arm are respectively hinged to the base, and the second connecting plate is used to connect the second left swing arm and the second right swing arm.

3. The clamping device for testing the tensile strength of a dog bone test block according to claim 2, characterized in that: The first limiter comprises a first front mounting seat, a first rear mounting seat, a first connecting rod, a first front regulating valve and a first rear regulating valve, wherein the first front mounting seat is mounted on the first left swing arm, the first rear mounting seat is mounted on the second left swing arm, the first end of the first connecting rod passes through the first front mounting seat, the second end of the first connecting rod passes through the first rear mounting seat, the first front regulating valve is sleeved on the first end, the first rear regulating valve is sleeved on the second end, and the clamping angle between the first clamp arm and the second clamp arm is limited by rotating the first front regulating valve and / or the first rear regulating valve; The second limiter includes a second front mounting seat, a second rear mounting seat, a second connecting rod, a second front regulating valve and a second rear regulating valve. The second front mounting seat is mounted on the first right swing arm, and the second rear mounting seat is mounted on the second right swing arm. The first end of the second connecting rod passes through the second front mounting seat, and the second end of the second connecting rod passes through the second rear mounting seat. The second front regulating valve is sleeved on the first end, and the second rear regulating valve is sleeved on the second end. The clamping angle between the first clamp arm and the second clamp arm is limited by rotating the second front regulating valve and / or the second rear regulating valve.

4. The clamping device for testing the tensile strength of a dog bone test block according to claim 3, characterized in that: A first stopper is disposed on the end surface of one end of the first rotating inner rod, and a first limit valve is sleeved on the other end.

5. The clamping device for testing the tensile strength of a dog bone test block according to claim 4, characterized in that: The first limiting and clamping device includes second limiting grooves arranged on both sides of the first arc block and second limiting protrusions arranged on both sides of the first clamping sleeve. The free end of each second limiting protrusion is respectively located in each second limiting groove, and each second limiting protrusion is provided with a plurality of second placement grooves, and each second placement groove has a built-in clamping spring.

6. The clamping device for dog bone test block tensile strength testing according to claim 5, characterized in that: A plurality of third placement grooves are respectively arranged on both sides of the first clamping sleeve, and a compression spring is built in each of the third placement grooves.

7. The clamping device for dog bone test block tensile strength testing according to claim 6, characterized in that: A plurality of fourth placement grooves are respectively arranged on both sides of the first wedge-shaped plate, and a compression spring is built in each of the fourth placement grooves.

8. The clamping device for testing the tensile strength of a dog bone test block according to claim 1, characterized in that: A clamping rod is provided on the outer surface of the base, the clamping rod is located at the center of the base, and a connecting thread is provided on the outer surface of the clamping rod.

9. A method for using the clamping device for testing the tensile strength of a dog-bone test block according to any one of claims 1 to 8, characterized in that: The following steps are involved: The bases in the first clamping mechanism and the second clamping mechanism are respectively fixed by using the chuck of a universal testing machine, and the first clamping mechanism and the second clamping mechanism are symmetrically arranged; Placing two ends of the dog-bone test block in the first clamping mechanism and the second clamping mechanism respectively, and adjusting the first clamping mechanism and the second clamping mechanism respectively to clamp the dog-bone test block, wherein the first clamping mechanism and the second clamping mechanism are used in the same manner; The method for using the first clamping mechanism comprises the following steps: Rotate the first clamp arm and the second clamp arm to contact the detection part of the dog bone test block, and adjust the first limiter and the second limiter to initially fix the first clamp angle formed between the first clamp arm and the second clamp arm; The universal testing machine is adjusted so that the arc-shaped chuck contacts the dog-bone test block, the first adjustment jaw and the second adjustment jaw are adjusted to completely fit the variable diameter area of ​​the dog-bone test block, and then the first adjustment jaw and the second adjustment jaw are fixed, and the first limiter and the second limiter are further adjusted to fix the second clamping angle formed between the first clamp arm and the second clamp arm.

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