A hardness tester for inspecting a machined work product

Abstract

This invention relates to the field of hardness testing technology, and discloses a hardness tester for inspecting machined workpieces. The tester includes a body, a testing platform mounted on the body, a mounting base mounted on the body, and a testing indenter mounted on the mounting base. It also includes a slow-release buffering mechanism located inside the mounting base. The slow-release buffering mechanism includes a slow-release component located inside the mounting base and a stress-relief component located at the bottom of the slow-release component. This invention adds a slow-release buffering mechanism, relying on the cooperation of a slow-release spring and a rotating disk to achieve a slow and gradual release of the test load and stress. This effectively avoids sudden stress changes and impact tension during unloading, prevents microcracks and grain boundary damage around the indentation of brittle, low-plasticity new material workpieces, eliminates hardness value deviations and misjudgments of material properties caused by hidden structural damage to the workpiece, and significantly improves the authenticity, accuracy, and repeatability of workpiece hardness test results.

Description

Technical Field

[0001] This invention relates to the field of hardness testing technology, and in particular to a hardness tester for inspecting machined workpieces. Background Technology

[0002] In the hardness testing of machined workpieces, traditional hardness testing devices often adopt a rigid direct-connection structure, where the test indenter is directly and rigidly connected to the drive mechanism. This lack of an effective buffering mechanism leads to several problems during testing: First, the loading and unloading processes are too direct, lacking significant gradient damping. Instantaneous unloading can easily generate large stress impacts, affecting testing accuracy and potentially causing micro-cracks and deformation on the workpiece surface. Second, traditional devices lack reasonable trajectory constraints, making the test indenter prone to deviation. Force transmission during loading is unstable, and there is a lack of effective control over the rebound speed, resulting in poor accuracy and consistency of the test data. Third, the spring is prone to twisting and jamming during extension and retraction, causing uneven testing and affecting the accuracy of the test results.

[0003] With the development of the machining industry, the requirements for the accuracy and stability of hardness testing are constantly increasing, especially for the testing of brittle new materials, which requires balancing the rigidity of loading and the smoothness of unloading. Traditional rigid direct connection and instantaneous unloading modes can no longer meet the testing needs of new materials, easily leading to data distortion and misjudgment of performance. This invention, through optimized structural design and the addition of a rotating disk and damping components, solves the shortcomings of traditional devices. Combined with the A-shaped groove trajectory and the buffering effect of the torsion spring, it achieves precise control of loading and unloading, ensuring testing accuracy while effectively protecting the workpiece, thus meeting the high-precision and high-stability testing requirements of modern machining. Summary of the Invention

[0004] In view of the problems of existing technology, such as rigid direct connection during hardness testing, lack of buffering during unloading, and uncontrollable rebound speed, which can easily lead to distorted test data and damage to brittle workpieces, a hardness tester for inspection of machined workpieces is proposed.

[0005] Its purpose is to optimize the testing experience by using a slow-release buffer structure in conjunction with damping to achieve smooth unloading and gradual stress release, avoiding the impact and workpiece damage caused by instantaneous rebound; ensure loading accuracy and stability, eliminate testing misjudgments, improve the smoothness and durability of the device's operation, adapt to the high-precision testing needs of various machined workpieces, especially brittle new materials, and reduce equipment failure and maintenance costs.

[0006] The technical solution of the present invention is a hardness tester for inspecting machined workpieces, including a body, a test platform disposed on the body, a mounting base disposed on the body, and a test indenter disposed on the mounting base, and also includes a slow-release buffer force relief mechanism disposed inside the mounting base. The slow-release buffer force relief mechanism includes a slow-release component disposed inside the mounting base, and a force relief component disposed at the bottom of the slow-release component; The slow-release component is used to prevent the test head from rebounding and unloading rapidly after the test is completed. The unloading component is used to reduce the rebound speed of the slow-release component. The slow-release component includes a slow-release sleeve disposed at the bottom of the mounting base, a slow-release spring disposed in the slow-release sleeve, and a slow-release column disposed in the slow-release sleeve. The test head is fixedly connected to the bottom of the slow-release column.

[0007] Furthermore, the slow-release assembly also includes a rotating disk disposed at the bottom of the slow-release spring, the rotating disk being limited to rotating at the top of the slow-release column.

[0008] Furthermore, the stress-relieving assembly includes a cavity formed inside the slow-release sleeve, a stress-relieving ring disposed within the cavity, a ring array of stress-relieving grooves formed inside the stress-relieving ring, a rotating groove formed in the middle of the slow-release column, a rotating ring disposed within the rotating groove, a rotating torsion spring disposed between the rotating ring and the rotating groove, and a rotating rod arranged in a ring array on the rotating ring, wherein the rotating rod is movably connected within the stress-relieving groove group.

[0009] Furthermore, the unloading groove assembly includes an unloading groove one formed on the unloading ring, and an unloading groove two that is smoothly connected to the unloading groove one.

[0010] Furthermore, the first and second unloading grooves are symmetrically distributed vertically, together forming an inverted A-shape.

[0011] Furthermore, the surfaces of the walls of the first and second unloading grooves are provided with a high-friction-coefficient wear-resistant damping material, which can provide stable and controllable frictional damping during the sliding of the rotating rod, thereby achieving gradient unloading.

[0012] Furthermore, when the rotating torsion spring is initially unstressed, the rotating rod is located at the ends of both sides of the unloading groove one and the unloading groove two.

[0013] Furthermore, symmetrical limiting grooves are formed on both sides of the bottom of the slow-release column, and limiting blocks are symmetrically connected to the bottom of the slow-release sleeve, with the limiting blocks slidingly connected within the limiting grooves.

[0014] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention incorporates a slow-release buffer stress relief mechanism, overcoming the structural drawbacks of traditional hardness testing equipment's rigid direct connection and instantaneous rebound. Relying on the coordinated action of a slow-release spring and a rotating disk, it achieves a gradual release of the test load and progressive stress relief. This effectively avoids sudden stress changes and impact tension during unloading, preventing microcracks and grain boundary damage around the indentation of brittle, low-plasticity new material workpieces. It also eliminates hardness value deviations and misjudgments of material properties caused by hidden structural damage to the workpiece, significantly improving the authenticity, accuracy, and repeatability of workpiece hardness test results.

[0015] 2. This invention employs a composite damping structure that combines an A-shaped interconnected unloading groove assembly, a rotating rod, a rotating torsion spring, and groove wall damping material. Unlike the single-spring vertical push-reset mode, this invention utilizes trajectory guidance, torsion spring torque, and friction damping to create graded resistance, achieving differentiated working effects such as low-resistance stable loading during downward pressure and gradual unloading. This ensures stable vertical force transmission during the loading phase, meeting hardness testing standards, while also allowing for independent adjustment of the rebound speed. The buffering and unloading effect is highly controllable, making it more widely applicable.

[0016] 3. Through the axial limiting and guiding of the limiting groove and limiting block, and the anti-torsion and anti-jamming structure design of the rotating disk, the circumferential offset and radial movement of the release column are effectively limited, avoiding problems such as spring extension and torsion, component jamming and uneven wear, ensuring precise coordination and smooth operation of all moving parts. The whole adopts a pure mechanical linkage structure, requiring no additional electrical control assistance. The structure is compact and stable, with a low failure rate, wear resistance and durability. It can be adapted to continuous batch testing operations in the workshop for a long time, significantly reducing equipment maintenance costs and extending the overall service life of the device. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall three-dimensional structure of the present invention; Figure 2 This is a schematic diagram of the overall structure of the test head of the present invention; Figure 3 This is a schematic diagram of the overall front cross-sectional structure of the slow-release buffer force relief mechanism of the present invention; Figure 4 This is a partial half-section diagram of the slow-release buffer force relief mechanism of the present invention; Figure 5 This is an exploded view of the overall structure of the sustained-release component and the force-relieving component of the present invention; Figure 6 This is an exploded structural diagram of the unloading ring and rotating ring of the present invention; Figure 7 This is a front view of the unloading groove assembly and a schematic diagram of the moving direction of the rotating rod of the present invention; Figure 8 This is a schematic diagram of the springback structure of the conventional test indenter of the present invention when testing the surface hardness of a workpiece.

[0018] In the picture: 1. Body; 11. Test platform; 12. Mounting base; 13. Test pressure head; 2. Slow-release assembly; 21. Slow-release sleeve; 22. Slow-release spring; 23. Slow-release column; 24. Rotating disk; 3. Unloading assembly; 31. Cavity; 32. Unloading ring; 33. Unloading groove assembly; 331. Unloading groove one; 332. Unloading groove two; 34. Rotating groove; 35. Rotating ring; 36. Rotating rod; 4. Limiting groove; 5. Limiting block. Detailed Implementation

[0019] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0020] Example 1, referring to Figures 1-8 This invention provides a hardness tester for inspecting machined workpieces, comprising a body 1, a test platform 11 mounted on the body 1, a mounting base 12 mounted on the body 1, and a test indenter 13 mounted on the mounting base 12. It also includes a slow-release buffer unloading mechanism disposed inside the mounting base 12. The slow-release buffer unloading mechanism includes a slow-release component 2 disposed inside the mounting base 12 and an unloading component 3 disposed at the bottom of the slow-release component 2. The slow-release component 2 is used to prevent the test indenter 13 from instantly and rapidly rebounding and unloading after the test is completed, and the unloading component 3 is used to reduce the rebound speed of the slow-release component 2. The slow-release component 2 includes a slow-release sleeve 21 fixedly connected to the bottom of the mounting base 12, a slow-release spring 22 fixedly connected inside the slow-release sleeve 21, and a slow-release column 23 slidably connected inside the slow-release sleeve 21. The test indenter 13 is fixedly connected to the bottom of the slow-release column 23.

[0021] Specifically, traditional hardness testing devices employ a rigid direct-connection loading structure. The unloading process lacks buffering, the unloading speed is uncontrollable, and the load rebounds instantaneously. For machined workpieces made of new materials with high hardness, low plasticity, and brittleness, sudden stress changes can easily cause microcracks and grain boundary damage around the indentation. Minor deformation differences cannot be captured by conventional testing structures, easily leading to misjudgments of material brittleness indicators and hardness performance, resulting in poor testing accuracy and consistency. During the loading process, external driving force moves the mounting base 12 and the testing indenter 13 downwards to contact the workpiece. The release column 23 then moves upwards and compresses the release spring 22. After the test, the external driving force moves the mounting base 12 upwards, at which point the release spring 22 slowly extends. Due to the effect of the release spring 22, the testing indenter 13 is not immediately removed from the workpiece surface; a certain force remains on the workpiece surface, preventing microcracks and grain boundary damage around the indentation, thus avoiding misjudgments of material brittleness indicators and hardness performance. This structure utilizes the gradual reset action of the release spring 22 to achieve smooth and gradual load release and stress relief after testing. This effectively avoids stress impact and hidden damage to the workpiece caused by instantaneous rebound, significantly improving the authenticity and accuracy of hardness testing for brittle new materials and precision-machined workpieces. It ensures stable and reliable test data, greatly reduces the risk of misjudgment of material properties, and is particularly suitable for the high-precision inspection needs of new material workpieces. Reference Figures 3-5 The slow-release component 2 also includes a rotating disk 24 fixedly connected to the bottom of the slow-release spring 22, and the rotating disk 24 is limited to rotating at the top of the slow-release column 23.

[0022] Specifically, a flexible connection structure that allows relative rotation is formed between the release spring 22 and the release column 23. While ensuring stable transmission of axial loading and restoring forces, this allows for a slight circumferential rotation between the release column 23 and the rotating disk 24. This prevents circumferential torsion, jamming, or stress concentration of the release spring 22 during extension and retraction, ensuring smooth up-and-down movement and stable, uniform rebound of the release column 23. Combined with the rotational action of the unloading component 3, rotation and axial restoring do not interfere with each other, further ensuring the effect of slow, gradual unloading and progressive stress release. This better protects brittle new material workpieces from microcracks and grain boundary damage, improving detection consistency and reliability. Example 2, refer to Figures 3-7 This is the second embodiment of the present invention. The difference between this embodiment and the first embodiment is that the unloading component 3 includes a cavity 31 opened inside the slow-release sleeve 21, an unloading ring 32 fixedly connected inside the cavity 31, an annular array of unloading grooves 33 opened inside the unloading ring 32, a rotating groove 34 opened in the middle of the slow-release column 23, a rotating ring 35 rotatably connected inside the rotating groove 34, a rotating torsion spring abutting between the rotating ring 35 and the rotating groove 34, and an annular array of rotating rods 36 fixedly connected to the rotating ring 35, and the rotating rods 36 are movably connected inside the unloading grooves 33.

[0023] Specifically, when the test is completed and the release spring 22 pushes the release column 23 to rebound downwards and reset, the rotating rod 36 moves along the unloading groove group 33. Under the guidance of the groove, it drives the rotating ring 35 to overcome the force of the rotating torsion spring and generate synchronous deflection. By utilizing the motion constraint between the groove and the rotating rod 36, and in conjunction with the torsional damping of the rotating torsion spring, the rebound speed is gradually limited, making the rebound process smoother and more controllable.

[0024] Reference Figures 6-7 The unloading groove assembly 33 includes an unloading groove 331 formed on the unloading ring 32 and an unloading groove 332 that is smoothly connected to the unloading groove 331.

[0025] Specifically, during the pressure test, the rotating rod 36 moves from the end of the second unloading groove 332 to the middle of the unloading groove group 33, and then to the end of the first unloading groove 331. During this process, the rotating torsion spring is first twisted and then restored. Similarly, during its movement after the test, the rotating torsion spring also undergoes a process of being twisted and then reset. This achieves controllable bidirectional damping during loading and unloading, with smooth and gentle resistance during the pressure phase, ensuring stable transmission of the test load and guaranteeing the accuracy of hardness testing. The rotating torsion spring follows a regular movement of first twisting and then resetting throughout the entire process, resulting in uniform force distribution without impact, avoiding sudden stress changes and mechanism jamming, leading to more stable operation and longer lifespan. Through the guide of the groove and the torsion spring torque, a progressive damping effect is formed, truly achieving slow gradient unloading and stable stress release, avoiding the impact of instantaneous rebound, effectively preventing indentation microcracks and grain boundary damage in brittle new material workpieces during unloading, eliminating data distortion and performance misjudgment, and significantly improving the accuracy and consistency of hardness testing for machined new material workpieces.

[0026] Compared to the traditional method of relying solely on a spring for vertical push-reset, this structure, through the coordinated trajectory of unloading groove 1 (331) and unloading groove 2 (332), combined with the motion law of the rotating rod 36 and the rotating torsion spring first twisting and then resetting, transforms the simple vertical linear rebound into a segmented, slow-motion reset with trajectory constraints and torsional damping. This effectively avoids the impact caused by instantaneous rebound and sudden stress changes, truly achieving slow, gradient unloading and gradual stress release. It ensures rigid force transmission during the testing loading phase without affecting detection accuracy, while also providing smooth buffering during unloading to prevent micro-cracks and grain boundary damage in brittle new material workpieces, eliminating data distortion and performance misjudgment, and significantly improving the operational stability and service life of the mechanism. Reference Figure 7 The unloading groove 1 331 and the unloading groove 2 332 are symmetrically distributed vertically, and together they form an inverted A-shape.

[0027] Specifically, during the entire process of pressing down and rebounding unloading, the rotating rod 36 moves along the trajectory of the A-shaped groove, always maintaining a force state of first torsion to store energy and then smoothly reset, with continuous movement without sudden changes.

[0028] Reference Figures 1-7 The surfaces of the unloading groove 331 and unloading groove 332 are provided with a high friction coefficient wear-resistant damping material, which can provide stable and controllable friction damping during the sliding of the rotating rod 36, and realize gradient unloading.

[0029] Specifically, through the frictional cooperation between the damping material of the groove wall and the rotating rod 36, the buffering effect during the unloading stage is significantly improved without affecting the rigidity of the downward loading or reducing the accuracy of hardness testing. This further strengthens the role of slow gradient unloading and gradual stress release, more effectively avoids instantaneous rebound impact, prevents indentation microcracks and grain boundary damage in brittle new material workpieces, improves the stability of the mechanism's movement, reduces wear, extends service life, and makes the test results more realistic and reliable.

[0030] Reference Figures 6-7 When the rotating torsion spring is initially unstressed, the rotating rod 36 is located at the ends of both sides of the unloading groove 331 and the unloading groove 332.

[0031] Specifically, this setting ensures that the rotating rod 36 always moves according to the stable law of first torsion to store energy and then reset to release energy throughout the entire loading and unloading process, avoiding damping failure, motion jamming or uncontrolled rebound caused by initial position deviation, making the effect of slow gradient unloading and gradual stress release more stable and reliable, while ensuring the consistency of action and data repeatability of multiple continuous tests, further improving the stability and safety of testing brittle new material workpieces.

[0032] Reference Figures 3-4 The bottom of the slow-release column 23 has symmetrically opened limit grooves 4 on both sides, and the bottom of the slow-release sleeve 21 is symmetrically connected to limit blocks 5, and the limit blocks 5 are slidably connected in the limit grooves 4.

[0033] Specifically, it can effectively prevent the slow-release column 23 from rotating, deviating, or tilting, ensuring that the rotating rod 36 always accurately corresponds to the trajectory of the unloading groove group 33, avoiding misalignment, jamming, and damping failure; at the same time, it stabilizes the vertical movement accuracy, ensuring that the test indenter 13 always presses down vertically, guaranteeing accurate hardness test data; and in conjunction with the overall slow-release buffer structure, it ensures stable output of gradient unloading action, continuously and smoothly releasing stress, and improving the overall smoothness of the mechanism's operation and long-term stability. The remaining structures are the same as those in Embodiment 1.

[0034] Based on embodiments 1-2, the working principle of this invention is as follows: The hardness tester for inspecting machined workpieces of this invention, through a slow-release buffer force relief mechanism, solves the problem of instantaneous rebound during unloading in traditional rigid direct-connection structures, achieving slow gradient unloading and gradual stress release. In the initial state of the device, the rotating torsion spring is in a state of no force. The rotating rod 36 is at the end of the second unloading groove 332. The limiting block 5 and the limiting groove 4 cooperate to circumferentially limit the slow-release column 23, ensuring the accurate position of each component. During testing, the external driving force drives the mounting base 12 and the test pressure head 13 downward. After contacting the machined workpiece to be tested, the slow-release column 23 slides upward along the slow-release sleeve 21, compressing the slow-release spring 22. At this time, the rotating rod 36 moves from the end of the second unloading groove 332 along the A-shaped groove to the end of the first unloading groove 331. The rotating torsion spring is first twisted and stored energy and then gradually reset. The high-friction damping material of the groove wall provides slight damping, ensuring rigid force transmission and load stability during the loading process, without affecting the hardness detection accuracy. After the test is completed, the external driving force is removed, and the release spring 22 pushes the release column 23 and the test pressure head 13 to rebound upwards. The rotating rod 36 returns along its original path, undergoing the process of first torsion and then reset by the rotating torsion spring. The A-shaped groove constrains the movement of the rotating rod 36, and the damping material of the groove wall and the torque of the rotating torsion spring gradually increase the rebound resistance, achieving gradient unloading. Throughout the process, the rotating disk 24 allows the release column 23 and the release spring 22 to rotate relative to each other, preventing the spring from jamming. The limit block 5 and the limit groove 4 ensure that the release column 23 slides smoothly axially. The coordinated action of all components achieves smooth loading and gentle unloading, effectively protecting the brittle new material workpiece and eliminating false detection.

[0035] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A hardness tester for inspecting machined workpieces, comprising a body (1), a test platform (11) disposed on the body (1), a mounting base (12) disposed on the body (1), and a test indenter (13) disposed on the mounting base (12), characterized in that, It also includes a slow-release buffer force relief mechanism disposed inside the mounting base (12); The slow-release buffer unloading mechanism includes a slow-release component (2) disposed inside the mounting base (12) and an unloading component (3) disposed at the bottom of the slow-release component (2). The slow-release component (2) is used to prevent the test head (13) from rebounding and unloading instantly after the test is completed. The unloading component (3) is used to reduce the rebound speed of the slow-release component (2). The slow-release component (2) includes a slow-release sleeve (21) set at the bottom of the mounting base (12), a slow-release spring (22) set in the slow-release sleeve (21), and a slow-release column (23) set in the slow-release sleeve (21). The test head (13) is fixedly connected to the bottom of the slow-release column (23).

2. The hardness tester for inspecting machined workpieces according to claim 1, characterized in that: The slow-release assembly (2) also includes a rotating disk (24) disposed at the bottom of the slow-release spring (22), the rotating disk (24) being limited to rotating at the top of the slow-release column (23).

3. The hardness tester for inspecting machined workpieces according to claim 1, characterized in that: The unloading assembly (3) includes a cavity (31) opened inside the slow-release sleeve (21), an unloading ring (32) disposed in the cavity (31), an unloading groove group (33) arranged in a ring array inside the unloading ring (32), a rotating groove (34) opened in the middle of the slow-release column (23), a rotating ring (35) disposed in the rotating groove (34), a rotating torsion spring disposed between the rotating ring (35) and the rotating groove (34), and a rotating rod (36) arranged in a ring array on the rotating ring (35), and the rotating rod (36) is movably connected in the unloading groove group (33).

4. The hardness tester for inspecting machined workpieces according to claim 3, characterized in that: The unloading groove group (33) includes unloading groove one (331) opened on the unloading ring (32) and unloading groove two (332) smoothly connected to unloading groove one (331).

5. A hardness tester for inspecting machined workpieces according to claim 4, characterized in that: The unloading groove one (331) and unloading groove two (332) are symmetrically distributed vertically, and together they form an inverted A-shape.

6. A hardness tester for inspecting machined workpieces according to claim 5, characterized in that: The surfaces of the unloading groove one (331) and unloading groove two (332) are provided with a high friction coefficient wear-resistant damping material, which can provide stable and controllable friction damping during the sliding of the rotating rod (36) to achieve gradient unloading.

7. A hardness tester for inspecting machined workpieces according to claim 6, characterized in that: When the rotating torsion spring is initially unforced, the rotating rod (36) is located at the ends of the two sides of the unloading groove one (331) and the unloading groove two (332).

8. A hardness tester for inspecting machined workpieces according to claim 1, characterized in that: The bottom of the slow-release column (23) has symmetrically opened limit grooves (4) on both sides, and the bottom of the slow-release sleeve (21) is symmetrically connected to limit blocks (5), and the limit blocks (5) are slidably connected in the limit grooves (4).

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