A device for testing the shape retention strength of sports protective gear

Abstract

This invention relates to the field of material mechanical property testing technology, specifically to a shape retention force testing device for sports protective gear. The device includes a testing platform, an upper test piece, a lower test piece, a power drive module, and a mechanical sensor. It also includes an upper test compensation component, a lower test compensation component, two external magnetic components, two sets of displacement guiding components, an auxiliary reset component, a clamping component, and a universal follow-up component. The upper test compensation component is sleeved on the outer periphery of the upper test piece. This invention solves the problems in existing technologies where rigid constraints lead to limited natural strain paths, distorted stress distribution, and parameter acquisition reference failure due to zero-position offset of the tested component during long-cycle testing. It can adapt to the radial dynamic expansion and contraction requirements of the knee brace during flexion and extension without rigid boundary constraints, ensuring that the natural strain path is not interfered with, while automatically maintaining test zero-position consistency and improving the accuracy of mechanical parameter acquisition.

Description

Technical Field

[0001] This invention relates to the field of material mechanical property testing technology, specifically to a device for testing the shape retention strength of sports protective gear. Background Technology

[0002] For the physical and mechanical properties characterization of flexible elastic fabric materials (such as sports knee braces) during simulated dynamic service, existing technologies typically construct material mechanics analysis systems, simulate complex deformation environments through loading mechanisms, and utilize load detection elements (mechanical sensors) to collect stress distribution, hysteresis rebound curves, and fatigue stress decay characteristics of the material under dynamic cyclic loading in real time.

[0003] When performing long-cycle cyclic load analysis on this type of material, the test piece is prone to unexpected axial drift along the test reference axis, causing a relative offset between the physical sensing point and the force acquisition area, which disrupts the zero-position consistency and leads to the failure of the mechanical parameter acquisition reference under different cycle periods. In order to suppress displacement interference, existing technologies mostly use rigid limiting methods for boundary constraints. However, elastic fabrics undergo significant dynamic radial Poisson deformation during compression and stretching. Rigid constraints will produce a serious boundary interference effect, restricting the material's natural strain path. This will not only cause distortion of the internal stress field distribution of the material, causing the acquired physical and mechanical parameters to deviate from the true value, but also fail to adapt to the radial dynamic expansion and contraction requirements of the material during the stretching process, seriously affecting the accuracy and repeatability of material property analysis data.

[0004] To address this, a device for testing the shape retention strength of sports protective gear is proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a shape retention force testing device for sports protective gear. By using magnetic displacement to compensate for the deformation of the knee brace during the knee flexion and extension test, this invention solves the problems in the prior art where rigid constraints lead to limited natural strain paths and distorted stress distribution, as well as the failure of parameter acquisition references due to zero-position offset of the tested part during long-cycle testing. It can adapt to the radial dynamic expansion and contraction requirements of the knee brace during flexion and extension without rigid boundary constraints, ensuring that the natural strain path is not interfered with, while automatically maintaining the consistency of the test zero position and improving the accuracy of mechanical parameter acquisition.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A shape retention force testing device for sports protective gear includes a testing platform, an upper test piece, a lower test piece, a power drive module, and a force sensor. It also includes an upper test compensation piece, a lower test compensation piece, two external magnets, two sets of displacement guide assemblies, an auxiliary reset assembly, a clamping assembly, and a universal follow-up assembly. The upper test compensation piece is sleeved on the outer periphery of the upper test piece, and the lower test compensation piece is sleeved on the outer periphery of the lower test piece. The two external magnets are respectively fixed to the outer peripheries of the upper and lower test compensation pieces and are located at the front end of the testing platform. The two sets of displacement guide assemblies are respectively disposed on the outer peripheries of the upper and lower test pieces and are respectively connected to the upper and lower test compensation pieces. The auxiliary reset assembly is installed inside the displacement guide assembly on the outer periphery of the upper test piece. The clamping assemblies are respectively disposed on the upper test compensation piece. The universal follower assembly is installed inside the upper and lower test compensation components, respectively, and is connected to the clamping assembly. When the upper and lower test components bend relative to each other, the two external magnetic components deflect with the upper and lower test compensation components, respectively. After the magnetic force of the external magnetic components decays, the axial constraint decreases and cooperates with the displacement guiding assembly to compensate for the dynamic deformation displacement of the test component. When the upper and lower test components are reset, the strong magnetic repulsion generated by the two external magnetic components returning to a parallel state drives the upper and lower test compensation components to reset. The test component is restored to flatness under the action of the clamping assembly. When the upper test compensation component is reset, it maintains zero position consistency under the action of the progressive traction force provided by the auxiliary reset assembly. During the test, the clamping assembly follows the universal follower assembly at multiple angles and deforms with the test component.

[0008] Preferably, the two sets of displacement guiding components include linear guide rails and guide blocks. The linear guide rails are respectively opened on the outer periphery of the upper test piece and the lower test piece, and are arranged in a ring array along the outer periphery of the upper test piece and the lower test piece, respectively. The guide blocks are respectively fixed on the inner side of the upper test compensation piece and the lower test compensation piece, and are arranged in a ring array along the inner periphery of the upper test compensation piece and the lower test compensation piece, respectively. The guide blocks are slidably connected to the linear guide rails.

[0009] Preferably, both the upper and lower test pieces have limiting holes inside, and the limiting holes are located between the linear guides and connected to the corresponding linear guides. The end of the guide block is fixed with a guide rod connected to the limiting hole. The guide rod is located inside the upper and lower test compensation pieces and is arranged opposite to each other.

[0010] Preferably, the auxiliary reset component includes a fixed inner magnetic ring and a follower inner magnetic ring. The fixed inner magnetic ring is symmetrically fixed at the front end of the upper test piece, and the follower inner magnetic ring is fixed at the inner front end of the upper test compensation piece, and is located outside the fixed inner magnetic ring. A non-magnetic isolation ring is fixed inside the upper test compensation piece, and the non-magnetic isolation ring is located between the outer magnetic piece and the follower inner magnetic ring.

[0011] Preferably, a magnetic sheet is fixed inside the linear guide rail on the outer periphery of the upper test piece, a magnetic block is fixed at the end of the guide block on the inner side of the upper test compensation piece, and the magnetic block is located inside the linear guide rail on the outer periphery of the upper test piece, and the limiting hole of the upper test piece is filled with a magnetostrictive damping medium.

[0012] Preferably, the fixed inner magnetic ring and the follower inner magnetic ring are arranged coaxially with opposite polarities, and when the upper test compensation component is in the initial zero position, the fixed inner magnetic ring and the follower inner magnetic ring coincide in the axial projection, and the initial position of the upper test compensation component is locked by magnetic locking.

[0013] Preferably, the magnetic sheet is embedded along the length of the linear guide rail, and its magnetic strength decreases in a gradient distribution as it moves away from the test platform. Combined with the damping force generated by the magnetic block and the magnetostrictive damping medium, a dynamic and balanced progressive auxiliary traction force is formed during the resetting process of the upper test compensation component.

[0014] Preferably, the clamping assembly includes a first clamping piece and a second clamping piece. The first clamping piece is respectively disposed on the inner side of the upper test compensation member and the lower test compensation member, and is arranged in a ring array along the inner periphery of the upper test compensation member and the lower test compensation member, respectively. The second clamping piece is respectively disposed on the inner side of the upper test compensation member and the lower test compensation member, and is arranged in a ring array along the inner periphery of the upper test compensation member and the lower test compensation member, respectively.

[0015] Preferably, the second clamping piece has symmetrical through holes on its outer side, and the first clamping piece has symmetrical fixing rods that are adapted to the through holes on its outer side. The fixing rods pass through the through holes, and a telescopic spring is sleeved and fixed at the end of the fixing rods. The telescopic springs are connected to the outer side of the second clamping piece.

[0016] Preferably, the universal follower assembly includes a ball groove and a universal ball head. The ball groove is respectively opened on the inner side of the upper test compensation component and the lower test compensation component, and is distributed in a ring array along the inner periphery of the upper test compensation component and the lower test compensation component. The universal ball head is fixed on the outer side of the second clamping piece and is connected to the ball groove.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] 1. In application, during the knee bending test driven by the test platform, the external magnetic component deflects spatially along with the test compensation component, causing the magnetic coupling strength to decrease nonlinearly. This reduces the constraint force on the axial sliding of the knee brace, allowing the knee brace to slide on the leg mold according to the actual wearing state through the displacement guide component. After the leg mold straightens and resets, the external magnetic component moves axially along the guide rail with the test compensation component to reset, restoring the magnetic coupling strength between the external magnetic components and enhancing the magnetic repulsion force. The magnetic repulsion of the two external magnetic components drives the test compensation component to reset to the initial zero position on the leg mold, allowing the knee brace to be stretched and reset. In addition, the clamping component and the universal follower component clamp the two ends of the knee brace, allowing the ends of the knee brace to automatically adjust the angle and posture according to the dynamic deformation. This makes the force state of the knee brace closer to the actual wearing state of the human body. It can not only achieve a dynamic balance between the compensation degree of freedom and reset stability of the test compensation component, but also greatly improve the authenticity and accuracy of the pressure distribution data collected during the knee brace shape retention force test.

[0019] 2. Through the synergistic effect of the magnetic sheet, magnetic block and magnetostrictive damping medium in the auxiliary reset component, a progressive magnetic traction and damping adjustment effect is formed in the displacement guide component in the upper test piece. This enables the upper test compensation piece to generate a dynamically balanced progressive traction force when reset. Combined with the magnetic locking effect of the fixed inner magnetic ring and the follower inner magnetic ring at the zero position, the reset overshoot and zero position drift problems are avoided, ensuring that the initial position is consistent in each test cycle, thereby improving the data stability and reliability under long-term high-frequency cycle testing.

[0020] 3. Through the design of the first clamping plate, fixing rod, second clamping plate, through hole and telescopic spring, the end of the knee brace can be flexibly clamped, and the telescopic spring provides elastic buffering, which can adapt to changes in knee brace thickness and local tensile deformation. This avoids excessive pressure on the knee brace caused by traditional rigid compression structure, reduces the phenomenon of knee brace detachment and slippage during the test, and improves the fit stability between the knee brace and the leg mold, so as to collect more stable and accurate test data while ensuring the natural deformation of the knee brace. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0022] Figure 2 This is a cross-sectional view of the overall structure of the present invention;

[0023] Figure 3 For the present invention Figure 2 Enlarged schematic diagram of the structure at point A in the middle;

[0024] Figure 4 For the present invention Figure 2 Enlarged schematic diagram of the structure at point B;

[0025] Figure 5 This is an exploded view of the upper test piece structure of the present invention;

[0026] Figure 6 This is an exploded cross-sectional view of the upper test specimen structure of the present invention;

[0027] Figure 7 This is an exploded view of the lower test specimen structure of the present invention;

[0028] Figure 8 This is an exploded cross-sectional view of the lower test specimen structure of the present invention;

[0029] Figure 9 This is a schematic diagram of the bent state of the leg mold structure of the present invention.

[0030] In the diagram: 1. Test platform; 2. Upper test piece; 3. Lower test piece; 4. Power drive module; 5. Mechanical sensor; 6. Upper test compensation piece; 7. Lower test compensation piece; 8. External magnetic component; 9. Displacement guide assembly; 91. Linear guide rail; 911. Guide block; 92. Limiting hole; 921. Guide rod; 10. Auxiliary reset assembly; 101. Fixed inner magnetic ring; 102. Follower inner magnetic ring; 103. Magnetic sheet; 104. Magnetic block; 105. Magnetostrictive damping medium; 11. Clamping assembly; 111. First clamping piece; 1111. Fixed rod; 112. Second clamping piece; 1121. Through hole; 113. Telescopic spring; 12. Universal follower assembly; 121. Ball groove; 122. Universal ball head. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] Please see Figures 1 to 9 This invention provides a device for testing the shape retention strength of sports protective gear, the technical solution of which is as follows:

[0033] Reference Figure 1 , Figure 2 , Figure 5 , Figure 7 and Figure 9A shape retention force testing device for sports protective gear includes a testing platform 1, an upper test piece 2, a lower test piece 3, a power drive module 4, and a mechanical sensor 5. The testing platform 1 serves as the support base and control core of the entire testing device, providing a stable mechanical support environment for dynamic bending testing and ensuring that each moving part operates within a preset trajectory. The upper test piece 2 and lower test piece 3 simulate the anatomical structure of the human knee joint, providing a realistic biomimetic loading surface. Through their relative movement, the device simulates the flexion and extension movements of the knee joint during activities such as running and squatting, allowing the knee brace to withstand realistic dynamic stress. The power drive module 4 connects the power source to the leg model, converting the power from the testing platform 1 into the bending and repositioning movements of the leg model, and controlling the testing frequency and angle. Precise control of degree and speed ensures the consistency of the simulated motion cycle. Mechanical sensor 5 is integrated into the surface of the bionic test leg mold to monitor the physical parameters of the knee brace during dynamic deformation in real time. It can quantitatively test and analyze the pressure distribution, rebound force, and stress attenuation under cyclic fatigue, providing data support for evaluating the knee brace's shape retention capability. Since the knee brace is wrapped around the curved surface of the leg mold, flexible thin-film pressure sensors are used in an array. These sensors are extremely thin and flexible, allowing them to fit snugly against the outer periphery of the leg mold (i.e., between the knee brace and the leg mold contact surface), accurately capturing pressure changes at different points during flexion and extension. The system also includes an upper test compensation component 6, a lower test compensation component 7, two external magnets 8, and two sets of displacement guiding components. 9. The auxiliary reset assembly 10, clamping assembly 11, and universal follow-up assembly 12 are included. The upper test compensation component 6 is fitted around the outer periphery of the upper test component 2. During the bending test, it slides upwards with the stretching of the knee brace. Through the nonlinear attenuation of the magnetic force of the outer magnetic component 8, the axial constraint is reduced, allowing the knee brace to deform naturally. The lower test compensation component 7 is fitted around the outer periphery of the lower test component 3, synchronous with the upper test compensation component 6. During bending, it provides displacement compensation space through the attenuation of the magnetic force of the outer magnetic component 8, adapting to the extension and retraction requirements of the lower end of the knee brace. The two outer magnetic components 8 are respectively fixed around the outer periphery of the upper test compensation component 6 and the lower test compensation component 7. The outer magnetic components 8 are used to form a dynamically changing magnetic coupling relationship during the bending and reset process of the leg mold. During the bending process of the leg mold, the outer magnetic components 8 undergo spatial deflection with the test compensation component. The magnetic field direction deviates from the initial coaxial state, weakening the magnetic coupling strength and reducing the axial movement resistance of the test compensation component. When the leg mold returns to a straight state, the two external magnetic components 8 realign, enhancing the magnetic coupling and forming a magnetic repulsion force to drive the test compensation component to flexibly reset to its initial position. This achieves a dynamic balance between the compensation degree of freedom and reset stability of the test compensation component. Furthermore, the external magnetic components 8 are arranged with opposite poles, further generating magnetic repulsion. Located at the front end of the test platform 1, the upper test compensation component 6, the lower test compensation component 7, and the two external magnetic components 8 form the core of the dynamic compensation assembly. When the upper test component 2 and the lower test component 3 bend, the external magnetic components 8 spatially deflect with the corresponding test compensation component, causing nonlinear attenuation of the magnetic force, thereby reducing the axial constraint on the test compensation component.This design allows the knee brace to slide naturally as it stretches, avoiding the limitations imposed by traditional rigid fixation on material deformation. When the leg mold returns to a straight state, the outer magnetic component 8 realigns and generates enhanced magnetic repulsion, driving the upper test compensation component 6 and the lower test compensation component 7 to restore the knee brace to its flat position. This simulates the natural deformation path of the knee brace during actual use, improving the accuracy of test data and preventing premature fatigue failure of the material due to rigid constraints. Two sets of displacement guide components 9 are respectively located on the outer periphery of the upper test component 2 and the lower test component 3, and are connected to the upper test compensation component 6 and the lower test compensation component 7 respectively. The displacement guide components 9 are used to guide and limit the axial compensation movement of the upper test compensation component 6 and the lower test compensation component 7, ensuring that the test compensation components slide stably only along the axial direction of the leg mold, assisting in the recovery process. Positioning component 10 is installed within displacement guide component 9 on the outer periphery of upper test piece 2. Auxiliary reset component 10 provides progressive auxiliary reset traction force to upper test compensation component 6 during the process of the leg mold returning from a bent state to a straightened state, thereby avoiding reset overshoot, reset drift, and zero-position inconsistency during the reset process of the test compensation component, and improving repeatability accuracy during the test cycle. Clamping components 11 are respectively installed inside upper test compensation component 6 and lower test compensation component 7. Clamping components 11 are used to flexibly clamp and fix the upper and lower edges of the knee brace, thereby avoiding excessive local pressure on the knee brace caused by traditional rigid compression structures, and reducing the detachment and slippage of the knee brace during dynamic bending tests. Universal follower components 12 are respectively installed on upper test compensation component 6 and lower test compensation component 7. The test compensation component 7 is located inside the clamping assembly 11. The universal follower assembly 12 is used to realize the multi-degree-of-freedom spatial follower of the clamping assembly 11 relative to the test compensation component, thereby avoiding the clamping assembly 11 from forming a rigid restriction on the dynamic deformation path of the knee brace and improving the biomimetic fit effect during the dynamic test of the knee brace. When the upper test component 2 and the lower test component 3 bend relative to each other, the two outer magnetic components 8 deflect with the upper test compensation component 6 and the lower test compensation component 7 respectively. After the magnetic force of the outer magnetic component 8 decays, the axial constraint is reduced and it cooperates with the displacement guide assembly 9 to compensate for the dynamic deformation displacement of the test component. When the upper test component 2 and the lower test component 3 are reset, the strong magnetic repulsion generated by the two outer magnetic components 8 returning to the parallel state drives the upper test compensation component 6 and the lower test compensation component 7 to reset. The test component is in the clamping assembly 11. When the upper test compensation component 6 is reset, it maintains a consistent zero position under the progressive traction force provided by the auxiliary reset component 10. During the test, the clamping component 11 moves at multiple angles and deforms with the test component under the action of the universal follower component 12. The outer magnetic component 8 and the auxiliary reset component 10 adopt an independent magnetic circuit layout. The outer magnetic component 8 forms a magnetic repulsion magnetic field along the radial direction of the upper test compensation component 6 and the lower test compensation component 7 to achieve flexible reset of the test compensation component. The fixed inner magnetic ring 101 and the follower inner magnetic ring 102 form a magnetic adsorption magnetic field along the axial direction of the test component to achieve zero-position locking. The magnetic sheet 103 and the magnetic block 104 form a local progressive auxiliary traction magnetic field along the direction of the linear guide rail 91 to adjust the reset damping and auxiliary traction force.Because the aforementioned magnetic fields are located in different spatial regions and their directions are staggered, magnetic coupling interference between different magnetic circuits is reduced, ensuring that the outer magnetic component 8, the fixed inner magnetic ring 101, the follower inner magnetic ring 102, the magnetic sheet 103, and the magnetic block 104 can operate independently and stably. A non-magnetic isolation structure is provided between the outer magnetic component 8 and the auxiliary reset assembly 10. This non-magnetic isolation structure is made of aluminum alloy, polytetrafluoroethylene, PEEK engineering plastic, or nylon material to reduce magnetic field crosstalk and ensure magnetic circuit stability.

[0034] Furthermore, the upper test compensation component 6, the lower test compensation component 7, the guide block 911, and the connection structure that disconnects from the magnetic field area are all made of non-magnetic materials. Non-magnetic materials include polyetheretherketone (PEEK), polyoxymethylene (POM), polyamide (PA), polytetrafluoroethylene (PTFE), or aluminum alloy. By using non-magnetic materials, magnetic field adsorption or magnetic circuit distortion can be avoided by the test compensation component and the guide structure forming with the external magnetic component 8, the fixed inner magnetic ring 101, the follower inner magnetic ring 102, and the magnetic sheet 103. This ensures the stability of the magnetic field and the zero-position locking accuracy during the magnetic reset process. At the same time, non-magnetic materials have a low coefficient of friction, which can reduce the frictional resistance between the upper test compensation component 6 and the lower test compensation component 7 during axial sliding, and improve the smoothness of dynamic compensation motion and the accuracy of repeated testing.

[0035] Reference Figure 3 , Figure 4 , Figure 6 and Figure 8 In one embodiment of the present invention, specifically, the two sets of displacement guiding components 9 include linear guide rails 91 and guide blocks 911. The linear guide rails 91 are respectively opened on the outer periphery of the upper test piece 2 and the lower test piece 3, and are respectively arranged in a ring array along the outer periphery of the upper test piece 2 and the lower test piece 3. The guide blocks 911 are respectively fixed on the inner side of the upper test compensation piece 6 and the lower test compensation piece 7, and are respectively arranged in a ring array along the inner periphery of the upper test compensation piece 6 and the lower test compensation piece 7. The guide blocks 911 are slidably connected to the linear guide rails 91. Through the cooperation of the guide blocks 911 and the linear guide rails 91, the test compensation pieces (upper test compensation piece 6 and lower test compensation piece 7) can slide axially on the leg mold (upper test piece 2 and lower test piece 3), avoiding radial offset and rotational shaking of the test compensation pieces during axial sliding, thereby providing a low-friction sliding path for the axial movement of the test compensation pieces.

[0036] Reference Figure 3 , Figure 4 , Figure 6 and Figure 8In one embodiment of the present invention, specifically, both the upper test piece 2 and the lower test piece 3 have limiting holes 92 inside, and the limiting holes 92 are located between linear guide rails 91 and connected to the corresponding linear guide rails 91. The end of the guide block 911 is fixed with a guide rod 921 connected to the limiting hole 92. The guide rod 921 is located inside the upper test compensation piece 6 and the lower test compensation piece 7 respectively and is arranged opposite to each other. The guide rod 921 and the limiting hole 92 are the base connecting the test compensation piece and the leg mold (the upper test compensation piece 6 is connected to the upper test piece 2, and the lower test compensation piece 7 is connected to the lower test piece 3), which limits the range of motion of the test compensation piece (the upper test compensation piece 6 and the lower test compensation piece 7). During the axial movement of the test compensation piece, a telescopic guide is formed to improve the stability of the test compensation piece during the sliding process, thereby avoiding the test compensation piece from swaying, jamming and tilting during the dynamic compensation process, and improving the motion accuracy and test repeatability of the test compensation piece.

[0037] Reference Figure 3 , Figure 5 and Figure 6 In one embodiment of the present invention, the auxiliary reset assembly 10 specifically includes a fixed inner magnetic ring 101 and a follower inner magnetic ring 102. The fixed inner magnetic ring 101 is symmetrically fixed to the front end of the upper test piece 2, and the follower inner magnetic ring 102 is fixed to the inner front end of the upper test compensation piece 6, and is located outside the fixed inner magnetic ring 101. The fixed inner magnetic ring 101 and the follower inner magnetic ring 102 are coaxially arranged with opposite poles, thereby forming a magnetic attraction lock. When the upper test compensation piece 6 is close to the initial zero position, the axial projections of the two coincide, which enhances the magnetic attraction. Through the magnetic "locking" effect, the upper test compensation piece 6 is precisely locked in the initial position, thereby improving the upper test compensation. To ensure the zero-position locking stability during the reset process of component 6, a non-magnetic isolation ring is fixed inside the upper test compensation component 6. The non-magnetic isolation ring is located between the outer magnetic component 8 and the follower inner magnetic ring 102. The non-magnetic isolation ring is made of non-magnetic materials such as polyetheretherketone (PEEK), polytetrafluoroethylene (PTFE), nylon, or aluminum alloy. It is used to spatially isolate the outer reset magnetic field formed by the outer magnetic component 8 from the inner locking magnetic field formed by the auxiliary reset component 10, so as to reduce magnetic field crosstalk and avoid magnetic coupling interference between different magnetic circuits, thereby ensuring the magnetic reset stability of the outer magnetic component 8 and the zero-position locking accuracy of the fixed inner magnetic ring 101 and the follower inner magnetic ring 102.

[0038] Reference Figure 3 , Figure 5 and Figure 6In one embodiment of the present invention, specifically, a magnetic sheet 103 is fixed inside the linear guide rail 91 on the outer periphery of the upper test piece 2, and a magnetic block 104 is fixed at the end of the guide block 911 on the inner side of the upper test compensation piece 6. The magnetic block 104 is located inside the linear guide rail 91 on the outer periphery of the upper test piece 2. The magnetic sheet 103 is embedded in the linear guide rail 91 along the axial direction and its magnetic force is distributed in a "gradient weakening" manner. When the upper test compensation piece 6 climbs and resets, a progressive magnetic traction force is formed between the magnetic sheet 103 and the magnetic block 104. The limiting hole 92 of the upper test piece 2 is filled with a magnetostrictive damping medium 105, which is used to dampen the upper test compensation piece 6. The axial movement during the positioning process forms a variable damping adjustment. When the magnetic block 104 approaches the top of the magnetic sheet 103, the local magnetic field is enhanced, and the viscosity of the magnetostrictive damping medium 105 increases, thereby improving the reset damping of the upper test compensation component 6. When the magnetic force weakens, the magnetostrictive damping medium 105 returns to a low viscosity state to reduce the sliding resistance of the upper test compensation component 6 during the dynamic compensation process. This achieves dual-state motion control of the upper test compensation component 6, which reduces resistance sliding during the dynamic compensation stage and provides high-stability buffering during the reset stage. The magnetostrictive damping medium 105 is a magnetorheological fluid, which forms a locally closed magnetic circuit through the magnetic field control of the magnetic sheet 103 and the magnetic block 104.

[0039] Reference Figure 2 , Figure 3 , Figure 5 and Figure 6 In one embodiment of the present invention, the fixed inner magnetic ring 101 and the follower inner magnetic ring 102 are arranged coaxially with opposite polarities. The initial pose lock of the upper test compensation component 6 is achieved through the attractive force between the magnets with opposite polarities, ensuring the stability and accuracy of the upper test compensation component 6 in its initial state. The coaxial opposite polarity arrangement structure makes the attractive force between the magnets more uniform and stable, avoiding local stress concentration or insufficient attractive force, thus improving the reliability of the initial pose lock. When it is necessary to release the initial pose lock, only an external force greater than the magnetic attraction force needs to be applied to release the upper test compensation component 6. The compensation component 6 is released from its initial zero position, enabling flexible unlocking. When the upper test compensation component 6 is in its initial zero position, the fixed inner magnetic ring 101 and the follower inner magnetic ring 102 coincide in axial projection, achieving initial pose locking of the upper test compensation component 6 through magnetic locking. This prevents displacement or shaking of the upper test compensation component 6 in non-working states, ensuring the stability and reliability of the device. The design of the magnetic locking structure makes the locking operation simpler and more convenient, eliminating the need for additional mechanical locking devices or complex control circuits, thus reducing the complexity and cost of the device.

[0040] Reference Figure 3 and Figure 6In one embodiment of the present invention, the magnetic sheet 103 is embedded along the length of the linear guide rail 91, and its magnetic strength decreases in a gradient distribution as it moves away from the test platform 1. During the resetting process of the upper test compensation component 6, different intensities of magnetic traction are provided according to the position change of the upper test compensation component 6. Combined with the damping force generated by the magnetic block 104 and the magnetostrictive damping medium 105, a dynamically balanced progressive auxiliary traction force is formed. Through the rheological properties of the magnetostrictive damping medium 105, the damping force can be dynamically adjusted, which can effectively absorb and consume the vibration and impact energy generated during the resetting process of the upper test compensation component 6, and play a role in buffering and shock absorption. Combined with the auxiliary traction force generated by the gradient magnetic distribution structure, a dynamically balanced force system is formed, which enables the upper test compensation component 6 to be reset smoothly and steadily, and improves the operational stability of the device.

[0041] Reference Figure 5 , Figure 6 , Figure 7 and Figure 8 As one embodiment of the present invention, specifically, the clamping assembly 11 includes a first clamping piece 111 and a second clamping piece 112. The first clamping piece 111 is respectively disposed on the inner side of the upper test compensation member 6 and the lower test compensation member 7, and is distributed in a ring array along the inner periphery of the upper test compensation member 6 and the lower test compensation member 7. The second clamping piece 112 is respectively disposed on the inner side of the upper test compensation member 6 and the lower test compensation member 7, and is distributed in a ring array along the inner periphery of the upper test compensation member 6 and the lower test compensation member 7. The first clamping piece 111 and the second clamping piece 112 form a set of clamps. The clamping assembly 11 is composed of six sets of clamps in a ring array, so that the clamping assembly 11 can perform local partition clamping on the end of the knee brace. With the cooperation of the universal follower assembly 12, a biomimetic wrapping clamping is formed, so that when the leg mold bends, some clamping areas can be displaced more and some clamping areas can be displaced less (so that each clamp can adaptively adjust the angle), thereby forming a non-uniform adaptive deformation, making the test closer to the real human body.

[0042] Reference Figure 5 , Figure 6 , Figure 7 and Figure 8In one embodiment of the present invention, specifically, the outer side of the second clamping piece 112 is symmetrically provided with through holes 1121, and the outer side of the first clamping piece 111 is symmetrically fixed with fixing rods 1111 that are adapted to the through holes 1121. The fixing rods 1111 pass through the through holes 1121, and the end of the fixing rods 1111 is sleeved and fixed with a telescopic spring 113. The telescopic spring 113 is connected to the outer side of the second clamping piece 112. During the dynamic deformation of the knee brace, the telescopic spring 113 can allow a small amount of elastic expansion and contraction between the first clamping piece 111 and the second clamping piece 112 to adapt to changes in the thickness of the knee brace and local tensile deformation, thereby avoiding excessive local pressure on the knee brace caused by the traditional rigid compression structure, and reducing the phenomenon of detachment and slippage of the knee brace during the dynamic bending test.

[0043] Reference Figure 5 , Figure 6 , Figure 7 and Figure 8 As one embodiment of the present invention, specifically, the universal follower component 12 includes a ball groove 121 and a universal ball head 122. The ball groove 121 is respectively opened on the inner side of the upper test compensation component 6 and the lower test compensation component 7, and is distributed in a ring array along the inner periphery of the upper test compensation component 6 and the lower test compensation component 7. The universal ball head 122 is fixed on the outer side of the second clamping piece 112 and is connected to the ball groove 121. The universal ball head 122 and the ball groove 121 are rotatably connected, allowing the knee pad end clamped by the clamping component 11 to perform multi-degree-of-freedom spatial deflection, ensuring that the clamping part of the tested knee pad will not generate additional shear stress, so that the pressure distribution collected by the force sensor 5 is closer to the real human wearing state.

[0044] Working Principle: Before testing, the knee brace to be tested is placed around the upper test piece 2 and the lower test piece 3, and the upper and lower ends of the knee brace are respectively inserted into the corresponding clamping components 11. After the knee brace is bent and fixed, the test platform 1 is started, which drives the upper test piece 2 and the lower test piece 3 to perform relative flexion and extension movements through the power drive module 4, simulating the movement state of the human knee joint. The knee brace undergoes dynamic tensile deformation as the upper test piece 2 and the lower test piece 3 bend. At this time, the upper test compensation piece 6 and the lower test compensation piece 7 deflect synchronously as the upper test piece 2 and the lower test compensation piece 3 bend, causing the external magnetic components 8 on the upper test compensation piece 6 and the lower test compensation piece 7 to deflect simultaneously. This causes the relative position of the magnetic fields of the two external magnetic components 8 to deviate from the initial coaxial state, and the magnetic coupling strength decreases nonlinearly, reducing the axial constraint on the upper test compensation piece 6 and the lower test compensation piece 7. This allows the upper test compensation piece 6 and the lower test compensation piece 7 to compensate naturally with the knee brace, avoiding rigid constraints that limit the deformation of the knee brace and ensuring that the deformation path conforms to the actual use state. At the same time, the clamping components... 11. Under the action of the universal follower component 12, the two ends of the knee brace can achieve multi-degree-of-freedom spatial deflection, further improving the test fit. When the upper test piece 2 and the lower test piece 3 are reset to the straight state, the two external magnets 8 are repositioned with the leg mold, the magnetic coupling strength is restored, and the magnetic repulsion force is enhanced. Through the magnetic repulsion of the two external magnets 8, the upper test compensation piece 6 and the lower test compensation piece 7 are driven to reset to the initial zero position along the displacement guide component 9. During the reset process, the auxiliary reset component 10 provides a progressive traction force to the upper test compensation piece 6 to ensure that the initial positions of the upper test compensation piece 6 and the lower test compensation piece 7 are consistent before each test cycle. During the reset process of the upper test compensation piece 6 and the lower test compensation piece 7, the clamping component 11 will synchronously drive the two ends of the tested knee brace to return to flatness and maintain the stability of the fit with the leg mold, thus waiting for the next cycle of flexion and extension test. During the bending and straightening test, the mechanical sensor 5 collects the pressure and rebound stress data of each point of the knee brace in real time, providing a quantitative basis for shape retention force analysis.

[0045] Specifically, before testing, the knee brace to be tested is placed around the upper test piece 2 and the lower test piece 3. The upper and lower edges of the knee brace are inserted between the first clamping piece 111 and the second clamping piece 112 at the corresponding positions. The telescopic spring 113 contracts and rebounds, pulling the second clamping piece 112, which, together with the first clamping piece 111, provides flexible clamping to the edges of the knee brace, avoiding excessive deformation of the knee brace caused by rigid compression. After the knee brace is installed and fixed, the test platform 1 is started, driving the upper test piece 2 and the lower test piece 3 to perform relative flexion and extension movements through the power drive module 4, simulating the movement state of the human knee joint. The knee brace undergoes dynamic stretching deformation as the leg model bends. At this time, the upper test compensation piece 6 and the lower test compensation piece 7 drive the outer magnetic piece 8 to spatially deflect synchronously with the bending of the leg model. When the relative positions of the magnetic fields of the two external magnetic components 8 deviate from the initial coaxial state, the magnetic coupling strength decreases nonlinearly, reducing the axial constraint on the corresponding test compensation component. This allows the upper test compensation component 6 and the lower test compensation component 7 to slide inside the linear guide rail 91 via the guide block 911. This also causes the magnetic block 104 to move from its strong magnetic top to its weak magnetic bottom, weakening the magnetic force. At this point, the magnetostrictive damping medium 105 inside the limiting hole 92 returns to a low viscosity state, reducing the sliding damping of the upper test compensation component 6 during dynamic compensation. Simultaneously, as the guide block 911 moves, it causes the guide rod 921 to extend into the limiting hole 92, allowing the upper test compensation component 6 and the lower test compensation component 7 to slide along with the knee brace on the leg mold. Dynamic compensation is performed to avoid rigid constraints limiting the knee brace's deformation, ensuring the deformation path conforms to the actual usage state. Simultaneously, the first clamping piece 111 and the second clamping piece 112, through the cooperation of the universal ball joint 122 and the ball groove 121, achieve multi-degree-of-freedom spatial deflection with the knee brace's deformation, avoiding the clamping structure restricting the knee brace's natural deformation and further improving the test fit. The mechanical sensor 5 collects pressure and rebound stress data at various points on the knee brace in real time, providing quantitative basis for shape retention force analysis. When the upper test piece 2 and the lower test piece 3 are reset to the straightened state, the two external magnetic pieces 8 realign with the leg mold, restoring magnetic coupling strength and increasing magnetic repulsion. At this time, the magnetic repulsion of the two external magnetic pieces 8 drives the upper test compensation piece 6 and the lower test compensation piece 7 to... The guide block 911 slides inside the linear guide rail 91 to reset to the initial zero position. During the reset process, the magnetic block 104 at the end of the guide block 911 inside the upper test compensation component 6 moves along the magnetic sheet 103 with a gradient magnetic force fixed inside the linear guide rail 91. At this time, the magnetic force of the local magnetic field is enhanced, which increases the viscosity of the magnetostrictive damping medium 105, thereby increasing the reset damping of the upper test compensation component 6 and forming a gradually changing auxiliary traction force. This, together with the magnetic locking of the fixed inner magnetic ring 101 and the follower inner magnetic ring 102 when reaching the zero position, avoids reset overshoot or zero position drift, and ensures that the initial position is consistent in each test cycle. Repeating the above flexion and extension test cycle can complete the multi-cycle test of the knee brace shape retention force and obtain stable and repeatable test data.

[0046] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A shape retention force testing device for sports protective gear, comprising a testing platform, an upper test piece, a lower test piece, a power drive module, and a mechanical sensor, characterized in that: It also includes an upper test compensation component, a lower test compensation component, two external magnetic components, two sets of displacement guiding assemblies, an auxiliary reset assembly, a clamping assembly, and a universal follower assembly. The upper test compensation component is sleeved on the outer periphery of the upper test component, and the lower test compensation component is sleeved on the outer periphery of the lower test component. The two external magnetic components are respectively fixed on the outer periphery of the upper and lower test compensation components and are located at the front end of the test platform. The two sets of displacement guiding assemblies are respectively disposed on the outer periphery of the upper and lower test components and are respectively connected to the upper and lower test compensation components. The auxiliary reset assembly is installed inside the displacement guiding assembly on the outer periphery of the upper test component. The clamping assemblies are respectively disposed inside the upper and lower test compensation components. The universal follower assembly is respectively installed on... The upper and lower test compensation components are located inside each other and connected to the clamping assembly. When the upper and lower test components bend relative to each other, the two external magnetic components deflect with the upper and lower test compensation components respectively. After the magnetic force of the external magnetic components decays, the axial constraint decreases and cooperates with the displacement guiding assembly to compensate for the dynamic deformation displacement of the test piece. When the upper and lower test components are reset, the strong magnetic repulsion generated by the two external magnetic components returning to a parallel state drives the upper and lower test compensation components to reset. The test piece is restored to flatness under the action of the clamping assembly. When the upper test compensation component is reset, it maintains a zero position under the action of the progressive traction force provided by the auxiliary reset assembly. During the test, the clamping assembly moves at multiple angles under the action of the universal follower assembly and deforms with the test piece.

2. The shape retention force testing device for sports protective gear according to claim 1, characterized in that: The two sets of displacement guiding components include linear guide rails and guide blocks. The linear guide rails are respectively opened on the outer periphery of the upper test piece and the lower test piece, and are arranged in a ring array along the outer periphery of the upper test piece and the lower test piece, respectively. The guide blocks are respectively fixed on the inner side of the upper test compensation piece and the lower test compensation piece, and are arranged in a ring array along the inner periphery of the upper test compensation piece and the lower test compensation piece, respectively. The guide blocks are slidably connected to the linear guide rails.

3. The shape retention force testing device for sports protective gear according to claim 2, characterized in that: Both the upper and lower test pieces have limiting holes inside, and the limiting holes are located between the linear guide rails and connected to the corresponding linear guide rails. The end of the guide block is fixed with a guide rod connected to the limiting hole. The guide rod is located inside the upper test compensation piece and the lower test compensation piece respectively and is arranged opposite to each other.

4. The shape retention force testing device for sports protective gear according to claim 3, characterized in that: The auxiliary reset assembly includes a fixed inner magnetic ring and a follower inner magnetic ring. The fixed inner magnetic ring is symmetrically fixed at the front end of the upper test piece, and the follower inner magnetic ring is fixed at the inner front end of the upper test compensation piece, and is located outside the fixed inner magnetic ring. A non-magnetic isolation ring is fixed inside the upper test compensation piece, and the non-magnetic isolation ring is located between the outer magnetic piece and the follower inner magnetic ring.

5. The shape retention force testing device for sports protective gear according to claim 4, characterized in that: A magnetic sheet is fixed inside the linear guide rail on the outer periphery of the upper test piece, and a magnetic block is fixed at the end of the guide block on the inner side of the upper test compensation piece. The magnetic block is located inside the linear guide rail on the outer periphery of the upper test piece, and the limiting hole of the upper test piece is filled with a magnetostrictive damping medium.

6. The shape retention force testing device for sports protective gear according to claim 4, characterized in that: The fixed inner magnetic ring and the follower inner magnetic ring are arranged coaxially with opposite polarities. When the upper test compensation component is in the initial zero position, the fixed inner magnetic ring and the follower inner magnetic ring coincide in the axial projection. The initial position of the upper test compensation component is locked by magnetic locking.

7. The shape retention force testing device for sports protective gear according to claim 5, characterized in that: The magnetic sheet is embedded along the length of the linear guide rail, and its magnetic strength decreases in a gradient distribution as it moves away from the test platform. Combined with the damping force generated by the magnetic block and the magnetostrictive damping medium, a dynamic and balanced progressive auxiliary traction force is formed during the resetting process of the upper test compensation component.

8. The shape retention force testing device for sports protective gear according to claim 1, characterized in that: The clamping assembly includes a first clamping piece and a second clamping piece. The first clamping piece is respectively disposed on the inner side of the upper test compensation member and the lower test compensation member, and is arranged in a ring array along the inner periphery of the upper test compensation member and the lower test compensation member, respectively. The second clamping piece is respectively disposed on the inner side of the upper test compensation member and the lower test compensation member, and is arranged in a ring array along the inner periphery of the upper test compensation member and the lower test compensation member, respectively.

9. The shape retention force testing device for sports protective gear according to claim 8, characterized in that: The second clamping piece has symmetrical through holes on its outer side, and the first clamping piece has symmetrical fixing rods that are adapted to the through holes on its outer side. The fixing rods pass through the through holes, and a telescopic spring is sleeved and fixed at the end of the fixing rods. The telescopic springs are connected to the outer side of the second clamping piece.

10. The shape retention force testing device for sports protective gear according to claim 9, characterized in that: The universal follower assembly includes a ball groove and a universal ball head. The ball groove is respectively opened on the inner side of the upper test compensation component and the lower test compensation component, and is distributed in a ring array along the inner periphery of the upper test compensation component and the lower test compensation component. The universal ball head is fixed on the outer side of the second clamping piece and is connected to the ball groove.

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