Lasting fixture and method for material friction and slip resistance testing

Abstract

The present application provides a shoe last type clamping fixture and method for material friction and slip resistance performance test, the shoe last type clamping fixture comprises a shoe last type last body; the last body has a shoe last type three-dimensional outer surface for carrying a flexible material sample; the top of the last body is provided with a connecting structure for connecting with a moving part of a test device. The present application uses a shoe last type last body as a carrier, which makes the flexible material form a more actual wearing state of the fit and pressure shape on the three-dimensional curved surface, improves the authenticity and representativeness of the test working condition, reduces the shape distortion introduced by the plane clamping, and improves the engineering significance of the comparison between different materials. The stable clamping, reliable connection and high consistency test of the flexible material in the shoe in the slip interface test are realized.

Description

Technical Field

[0001] This invention relates to the field of material performance testing technology, and more particularly to a shoe last-type clamping fixture and method for testing the friction and anti-slip properties of materials. Specifically, this invention relates to a testing fixture combining a shoe last-type load-bearing structure and an installation connection structure, used to clamp flexible material samples and adapt them to friction / anti-slip testing equipment for measuring friction force or anti-slip performance. Background Technology

[0002] Currently, the friction and anti-slip properties of the shoe's internal interface (e.g., the relative slippage between the sock material and the insole / outsole material) directly affect foot stability, fit, and slippage risk during wear, making them crucial evaluation indicators for footwear product development and material selection. Existing technologies have established relatively mature testing systems for evaluating shoe exterior anti-slip properties. Standards such as ISO 13287 and STMF2913, a shoe last-type clamping fixture for testing the friction and anti-slip properties of materials, measure the friction / anti-slip performance between the shoe and the ground by applying a normal load and generating relative slippage / slippage tendency.

[0003] Meanwhile, in the field of material friction coefficient determination, there are also representative COF test methods such as STM D1894 and ISO8295, which are shoe last type clamping fixtures used for testing the friction and anti-slip performance of materials. These methods typically employ the relative sliding between the slider / carrier and the flat sample and measure the friction force.

[0004] However, for the "sock-insole" type of flexible material-flexible / porous material anti-slip interface inside the shoe, current common tests still mostly use methods such as cutting flat sheets and then clamping them together, fixing them with screws, or gluing them in place for friction tests. This approach generally has the following shortcomings in engineering practice: (1) Clamping boundary effect and surface contamination: Clamping or adhesive fixing can easily introduce local indentations, adhesive penetration or surface contamination, thereby changing the true friction characteristics of the material and causing the result to deviate from the actual wearing state; (2) The tension of flexible materials is difficult to be consistent: materials such as socks / knitted fabrics are prone to wrinkling, loosening or local slippage after clamping. The initial tension of different operators and different batches of samples is difficult to reproduce, resulting in large test dispersion. (3) It is difficult to simulate the three-dimensional curved surface fit and the real pressure form: the friction of the inner interface of the shoe is not only related to the surface roughness of the material, but also closely related to the curvature fit, compression deformation and contact area distribution. The traditional planar bearing method is difficult to reproduce the contact form under the condition of "foot / shoe last curved surface + covering". (4) Insufficient equipment compatibility and attitude stability: Conventional fixtures have limited versatility and are complicated to install and position; under the combined action of normal load and tangential force, the load may rotate slightly, wobble or loosen, affecting the repeatability and comparability of the test. Summary of the Invention

[0005] The purpose of this invention is to provide a shoe last-type clamping fixture for testing the friction and anti-slip performance of materials, in order to solve the problems existing in the prior art in the friction / anti-slip test of flexible materials, such as obvious clamping boundary effect, easy wrinkling and loosening of the sample leading to poor repeatability, difficulty in simulating the three-dimensional curved surface fitting state inside the shoe, and insufficient compatibility with the test equipment and unstable posture.

[0006] To solve the above-mentioned technical problems, the present invention provides a shoe last type clamping fixture for testing the friction and anti-slip performance of materials, including a shoe last-shaped body; The last body has a three-dimensional outer surface in the shape of a shoe last, which is used to support flexible material samples; The top of the last body is provided with a connecting structure for connecting with the moving part of the testing equipment.

[0007] In this application, the last body is preferably formed by 3D printing. Existing technologies typically cut materials into flat sheets and fix them to a flat carrier by clamping or gluing for friction testing, which is difficult to reflect the fit of the shoe's inner curved surface. This invention uses a last-type last body as a carrier, allowing the flexible material to form a fit and compression shape on a three-dimensional curved surface that more closely resembles the actual wearing condition. This improves the realism and representativeness of the test conditions, reduces morphological distortion introduced by planar clamping, and enhances the engineering significance of comparing different materials. It achieves stable clamping, reliable connection, and high consistency testing of flexible materials (especially sock-like materials) in the shoe's inner anti-slip interface (sock-insole).

[0008] Furthermore, the interior of the last body is either hollow or solid.

[0009] Furthermore, a fixing plate is fixedly provided on the top of the last body, and the fixing plate is provided with several connecting parts for connecting with the moving part of the testing equipment.

[0010] Furthermore, the connecting part includes a stud, a connecting groove, a connecting hole (such as a threaded hole), a locating pin, and / or a locating hole, etc.

[0011] The last body is securely connected to the moving part of the testing equipment via a fixed plate and fasteners such as nuts and washers.

[0012] Furthermore, the fixing plate is provided with a plurality of spaced connection holes; And / or, the connecting groove is a long groove with a T-shaped cross-section.

[0013] The fixed plate of this application is equipped with an adjustable adaptable structure (elongated groove / multiple holes), which improves the universal adaptability with the equipment end and can quickly match different equipment end clamping structures and positioning components.

[0014] More preferably, the last body has an internal cavity; the last body has multiple ventilation holes in the non-foot area; the ventilation holes connect the cavity and the surface of the last body.

[0015] Preferably, the system also includes an air pump connected to the cavity via an air passage to expel gas from the cavity and create a negative pressure within the cavity (external air enters the cavity through the vent holes under the action of the negative pressure). This negative pressure is used to adsorb the sample through the vent holes, increasing the friction between the sample and the surface of the last body, thereby simulating the squeezing of the inner surface of non-sole areas such as the shoe upper and vamp onto the sock sample, and the effect of this squeezing on the friction and anti-slip performance of the sample.

[0016] Furthermore, the ventilation holes are evenly distributed on the surface of the non-foot area of ​​the last body.

[0017] Preferably, it also includes a plug for the air inlet of the vent hole at one end of the surface of the last body. By selectively blocking part of the vent hole, the adsorption force of different areas of the surface of the last body (excluding the foot area) can be adjusted, thereby simulating the various compression forces on the sample from different areas of the foot and shoe.

[0018] Furthermore, a recessed platform is provided at the air inlet of the vent hole, and the plug is disposed within the recessed platform; the outer surface of the plug is flush with or smoothly transitions to the surface of the last body.

[0019] Preferably, the gas line is equipped with a one-way valve and a pressure regulating valve, etc.

[0020] Furthermore, a foot-shaped core for simulating a foot is movably disposed within the cavity; It also includes a telescopic mechanism, with its two ends connected to the foot-shaped core and the last body, respectively. The telescopic mechanism is used to drive the foot-shaped core to move back and forth in the cavity, adjust the distance between the foot-shaped core and the inner side of the cavity, thereby adjusting the suction force of the air holes in different areas of the last body, and thus simulating the back and forth movement of the foot inside the shoe, resulting in changes in the clamping force (i.e. the extrusion force mentioned above) on different areas of the sample.

[0021] Specifically, when the foot-shaped core moves forward under the drive of the telescopic mechanism, the distance between the foot-shaped core and the hollow heel area (or the rear part of the cavity) increases, which is conducive to increasing the airflow in this area, thereby improving the negative pressure adsorption force in this area. This can simulate the foot moving backward relative to the shoe and closely adhering to the heel area of ​​the shoe upper, increasing the clamping force of the sample (sock) in the heel area. Conversely, when the foot-shaped core moves backward under the action of the telescopic mechanism, the distance between the foot-shaped core and the hollow heel area decreases, and the negative pressure adsorption force in the heel area decreases accordingly; while the distance between the foot-shaped core and the hollow shoe upper area (or the front part of the cavity) increases, and the negative pressure adsorption force in the shoe upper area increases relatively. This can simulate the foot moving forward relative to the shoe, and the clamping force of the sample (sock) in the shoe upper area increases.

[0022] Furthermore, the telescopic mechanism is an electric telescopic rod, the main body of which is embedded in the inner wall of the cavity of the last body, and the telescopic end of the electric telescopic rod is connected to the foot-shaped core.

[0023] The samples include, but are not limited to, socks and sock covers.

[0024] The second aspect of this application discloses a method for testing the friction and anti-slip performance of materials using the above-mentioned shoe last-type clamping fixture; specifically including the following steps: S10. Connect the last body to the moving part of the testing equipment via a connecting structure; S20. Place the sample onto the last body; place the insole on the test platform of the testing equipment (below the last body); S30. Start the testing equipment to test the friction and anti-slip performance between the sample and the insole.

[0025] By adopting the above technical solution, the present invention has the following beneficial effects: This invention uses a shoe last-type toe box as a carrier, enabling flexible materials to form a fit and compression shape on a three-dimensional curved surface that more closely resembles the actual wearing condition. This improves the realism and representativeness of the test conditions, reduces morphological distortion introduced by planar clamping, and enhances the engineering significance of comparing different materials. It achieves stable clamping, reliable connection, and high consistency testing of flexible materials in the anti-slip interface of shoes. Attached Figure Description

[0026] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0027] Figure 1 This is a front view of the shoe last type clamping fixture provided in Embodiment 1 of the present invention; Figure 2 for Figure 1 The right view of the shoe last type clamping fixture shown; Figure 3 for Figure 1 Left view of the shoe last type clamping fixture shown; Figure 4 for Figure 1 Rear view of the shoe last type clamping fixture shown; Figure 5 for Figure 1 A top view of the shoe last type clamping fixture shown; Figure 6 This is a diagram showing the usage status of the shoe last clamp and the sample during the testing process. Figure 7 This is a schematic diagram of the structure of the last body in Example 2; Figure 8 for Figure 7 A magnified view of a section at point A in the middle; Figure 9 This is a schematic diagram of the structure of the last body in Example 3; Figure 10 This is a schematic diagram of the structure of the last body after the foot-shaped core moves forward in Example 3.

[0028] Figure label: 1-Sample; 2-Insole; 3-Testing equipment; 10-Last body; 11-Cavity; 12-Ventilation hole; 13-Plug; 20-Fixing plate; 21-Stud; 22-Long groove; 23-Connecting hole; 30-Air pump; 31-One-way valve; 32-Pressure regulating valve; 40-Foot core; 41-Telescopic mechanism. Detailed Implementation

[0029] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. 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.

[0030] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0031] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0032] The present invention will be further explained below with reference to specific embodiments.

[0033] Example 1 like Figure 1-6 As shown, this embodiment provides a shoe last-type clamping fixture for testing the friction and anti-slip performance of materials, including a shoe last-shaped head body 10; The last body 10 has a three-dimensional outer surface in the shape of a shoe last, which is used to support the flexible material sample 1 (or specimen); the surface of the last body 10 may optionally be provided with a plush layer.

[0034] The top of the last body 10 is provided with a connecting structure for connecting with the moving part of the testing equipment 3.

[0035] In this application, the last body 10 is preferably formed by 3D printing. Existing technologies typically cut materials into flat sheets and fix them to a flat carrier by clamping or gluing for friction testing, which is difficult to reflect the fit of the shoe's inner curved surface. This invention uses a last-type last body 10 as a carrier, allowing the flexible material to form a fit and pressure shape on a three-dimensional curved surface that more closely resembles the actual wearing condition. This improves the realism and representativeness of the test conditions, reduces morphological distortion introduced by planar clamping, and enhances the engineering significance of comparing different materials. It achieves stable clamping, reliable connection, and high consistency testing of flexible materials (especially sock-like materials) in the shoe's inner anti-slip interface (sock-insole 2).

[0036] The inside of the last body 10 is a hollow or solid structure.

[0037] In this embodiment, the connection structure includes a fixing plate 20 fixedly disposed on the top of the last body 10, wherein the fixing plate 20 is fixed to the top of the last body 10 by adhesive or by fasteners such as screws.

[0038] The fixed plate 20 is provided with several connecting parts for connecting with the moving part of the testing equipment 3. The connecting parts include, but are not limited to, studs 21, nuts, connecting grooves, connecting holes (such as threaded holes), locating pins and / or locating holes, etc. The last body 10 is fastened to the moving part of the testing equipment 3 through the fixed plate 20 and fasteners such as nuts and washers.

[0039] Preferably, the fixing plate 20 is provided with a plurality of spaced-apart connecting holes 23; and / or, the connecting groove is a long groove 22 with a T-shaped cross-section. The fixing plate 20 is provided with an adjustable adaptable structure (long groove / multiple holes), which can adapt to various specifications of last body 10, and can also adapt to different connection structures of testing equipment. It can quickly match different equipment end clamping structures and positioning parts, thus improving its universal adaptability.

[0040] This invention achieves stable clamping and reliable connection in friction / slip resistance testing of flexible materials through a shoe last-type three-dimensional load-bearing structure and an installation connection component with anti-torsional constraint and adjustable adaptability. In the application scenario of shoe anti-slip (sock cover-insole 2), it can significantly improve the authenticity, repeatability, universal adaptability and testing efficiency of the test, and has good engineering application value.

[0041] The second aspect of this application discloses a method for testing the friction and anti-slip performance of materials using the aforementioned shoe last-type clamping fixture; see [link to relevant documentation]. Figure 6 As shown, the specific steps include the following: S10. The last body 10 is connected to the moving part of the testing device 3 through a connecting structure; S20. Place the sample 1 onto the last body 10; place the insole 2 on the testing platform of the testing equipment 3 (below the last body 10). S30. Start the test equipment 3 to test the friction and anti-slip performance between sample 1 and insole 2.

[0042] Among them, sample 1 includes, but is not limited to, socks, sock covers, etc.

[0043] This invention uses a shoe last-type toe body 10 as a carrier, enabling the flexible material to form a fit and compression shape on a three-dimensional curved surface that more closely resembles the actual wearing condition. This improves the realism and representativeness of the test conditions, reduces morphological distortion introduced by planar clamping, and enhances the engineering significance of comparing different materials. It achieves stable clamping, reliable connection, and high consistency testing of flexible materials in the anti-slip interface testing of shoes.

[0044] By using a universal mounting connection component with an interchangeable last body 10, the system can be expanded to meet testing needs for different sizes, foot types, or contact areas. This enhances the scalability and reusability of the fixture system, satisfying the need for rapid comparative testing of multiple materials and operating conditions during the R&D phase.

[0045] Example 2 This embodiment is basically the same as embodiment 1, except that: See Figure 7-8 As shown, more preferably, the last body 10 has a cavity 11 inside; the last body 10 has a plurality of ventilation holes 12 in the non-foot area; the ventilation holes 12 are connected to the cavity 11 and the surface of the last body 10.

[0046] Preferably, it also includes an air pump 30, which is connected to the cavity 11 via an air passage to discharge the gas in the cavity 11 and create a negative pressure in the cavity 11 (external air enters the cavity 11 through the vent 12 under the action of the negative pressure); the negative pressure is used to adsorb the sample through the vent 12, increasing the friction between the sample 1 and the surface of the last body 10, thereby simulating the squeezing of the inner surface of the non-sole area of ​​the shoe upper, the shoe collar, etc. on the sock and other sample 1, and the effect of the squeezing on the friction and anti-slip performance of the sample 1.

[0047] Preferably, the vent holes 12 are evenly distributed on the surface of the non-foot area of ​​the last body 10. Alternatively, the vent holes 12 may be unevenly distributed as required by the design.

[0048] Preferably, the device further includes a plug 13, which serves as the air inlet for the vent hole 12 at one end of the surface of the last body 10. By selectively blocking part of the vent hole 12, the adsorption force on different areas of the surface of the last body 10 (excluding the foot area) can be adjusted, thereby simulating various compression forces exerted on the sample 1 by different areas of the foot and shoe. More preferably, a recessed platform is provided at the air inlet of the vent hole 12, and the plug 13 is disposed within the recessed platform; the outer surface of the plug 13 is flush with or smoothly transitions to the surface of the last body 10.

[0049] In addition, the gas path is equipped with a one-way valve 31 and a pressure regulating valve 32, etc., for controlling the magnitude of the negative pressure and the opening and closing of the gas path.

[0050] This embodiment simulates the clamping forces of different areas of the shoe on the socks, sock covers and other samples 1 in actual activities by setting negative pressure adsorption, as well as the changes in the direction and force of the pulling or squeezing of the entire sample 1 (especially its bottom) caused by the clamping force during the movement, thereby simulating the effect of the above-mentioned pulling and force changes on the friction and anti-slip performance of the bottom of the sample 1.

[0051] Example 3 This embodiment is basically the same as embodiment 2, except that: See Figure 9-10 As shown, in this embodiment, a foot-shaped core 40 for simulating a foot is movably disposed inside the cavity 11; It also includes a telescopic mechanism 41, the two ends of which are connected to the foot-shaped core 40 and the last body 10, respectively. The telescopic mechanism 41 is used to drive the foot-shaped core 40 to move back and forth in the cavity 11, adjust the distance between the foot-shaped core 40 and the inner side of the cavity 11, thereby adjusting the suction force of the air holes 12 in different areas of the last body 10, and thus simulating the back and forth movement of the foot inside the shoe, resulting in changes in the clamping force (i.e. the above-mentioned extrusion force) on different areas of the sample 1.

[0052] Specifically, when the foot-shaped core 40 moves forward under the drive of the telescopic mechanism 41, the distance between the foot-shaped core 40 and the heel area of ​​the cavity 11 (or the rear part of the cavity 11) increases, which is conducive to increasing the air flow in the area and thus improving the negative pressure adsorption force in the area. This can simulate the foot moving backward relative to the shoe and closely adhering to the heel area of ​​the shoe upper, increasing the clamping force of the sample 1 (sock) in the heel area. Conversely, when the foot-shaped core 40 moves backward under the drive of the telescopic mechanism 41, the distance between the foot-shaped core 40 and the heel area of ​​the cavity 11 decreases, and the negative pressure adsorption force in the heel area decreases accordingly; while the distance between the foot-shaped core 40 and the upper area of ​​the cavity 11 (or the front part of the cavity 11) increases, and the negative pressure adsorption force in the upper area increases relatively, thereby simulating the foot moving forward relative to the shoe, and the clamping force of the sample 1 (sock) in the upper area increases.

[0053] Furthermore, the telescopic mechanism 41 is an electric telescopic rod, the main body of which is embedded in the inner wall of the cavity 11 of the last body 10, and the telescopic end of the electric telescopic rod is connected to the foot core 40.

[0054] This embodiment simulates the clamping effect of the shoe on the socks, sock covers, and other samples 1 during actual activities by setting the foot-shaped core 40 to move forward and backward relative to the shoe (note that it is opposite to the direction of movement of the foot-shaped core 40), as well as the changes in the direction and force of the entire sample 1 being pulled or squeezed during the movement, thereby simulating the influence of the above-mentioned pulling and force changes on the friction and anti-slip performance of the bottom of the sample 1.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A shoe last-type clamping fixture for testing the friction and anti-slip properties of materials, characterized in that, Including the shoe last shape itself; The last body has a three-dimensional outer surface in the shape of a shoe last, which is used to support flexible material samples; The top of the last body is provided with a connecting structure for connecting with the moving part of the testing equipment.

2. The shoe last type clamping fixture according to claim 1, characterized in that, The inside of the last body is a hollow or solid structure.

3. The shoe last type clamping fixture according to claim 1, characterized in that, A fixing plate is fixedly installed on the top of the last body, and several connecting parts are provided on the fixing plate for connecting with the moving part of the testing equipment.

4. The shoe last type clamping fixture according to claim 3, characterized in that, The connecting part includes studs, connecting grooves, connecting holes, locating pins and / or locating holes, etc.

5. The shoe last type clamping fixture according to claim 3, characterized in that, The fixing plate is provided with multiple connection holes arranged at intervals; And / or, the connecting groove is a long groove with a T-shaped cross-section.

6. The shoe last type clamping fixture according to claim 1, characterized in that, The last body has an internal cavity; the last body has multiple ventilation holes in the non-foot area; the ventilation holes connect the cavity and the surface of the last body.

7. The shoe last type clamping fixture according to claim 6, characterized in that, It also includes an air pump, which is connected to the cavity through an air passage to discharge the gas in the cavity and create a negative pressure in the cavity. The negative pressure is used to adsorb the sample through the air vent, increasing the friction between the sample and the surface of the last body, thereby simulating the squeezing of the inner side of the non-sole area of ​​the shoe, such as the upper and the upper of the shoe, on the sample, and the effect of this squeezing on the friction and anti-slip performance of the sample.

8. The shoe last type clamping fixture according to claim 7, characterized in that, The ventilation holes are evenly distributed on the surface of the non-foot area of ​​the last body.

9. The shoe last type clamping fixture according to claim 7, characterized in that, It also includes a plug, which is used as an air inlet at one end of the surface of the last body for the vent hole. By selectively blocking part of the vent hole, the adsorption force on the surface of different areas of the last body can be adjusted, thereby simulating the various extrusion forces on the sample from different areas of the foot and shoe.

10. The shoe last type clamping fixture according to claim 9, characterized in that, A recessed platform is provided at the air inlet of the vent hole, and the plug is placed inside the recessed platform; the outer surface of the plug is flush with or smoothly transitions to the surface of the last body.

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