Elastic member stretching device

Abstract

The embodiment of the application belongs to the tensile technical field of elastic material, and relates to an elastic piece tensile device. The guiding movement component of the elastic piece tensile device is fixed to the support frame; N groups of guiding movement pieces are respectively arranged in correspondence with the tensile directions of N arms of the elastic piece; each group of guiding movement pieces comprises a guiding part and a movement part which cooperate with each other; each group of fixing pieces is fixed to the movement part of one group of guiding movement pieces and is used for fixing one arm of the elastic piece; each group of reversing pieces is arranged in correspondence with one group of guiding movement pieces; and the driving end of the driving component is drivingly connected with the rigid pull rope. The technical scheme provided by the application can simplify the structure of the elastic piece tensile device and improve the universality of the device.

Description

Technical Field

[0001] This application relates to the field of elastic material stretching technology, and more specifically, to an elastic element stretching device. Background Technology

[0002] Elastic or hyperelastic materials are commonly used in engineering practice, such as rubber, polymers, gels, and other highly elastic materials, as well as biomaterials like muscle and skin. They possess many excellent properties, including high elasticity, shock resistance, and wear resistance. Hyperelastic materials generally have a randomly oriented molecular chain network structure. Due to weak intermolecular forces and sparse cross-linking points between molecular chains, they can undergo very large deformations under external forces and completely recover to their initial state without energy dissipation after the external force is removed. Hyperelastic materials are typical nonlinear elastic materials, and their properties can be characterized by the material's constitutive relation (strain energy density function). Studying the complete constitutive relation of hyperelastic materials and constructing their strain energy density function is crucial, having positive significance for scientific research and engineering applications, and is a core issue of widespread interest. Tensile testing is an important method for testing the mechanical properties of hyperelastic / rubber materials.

[0003] Currently, tensile testing apparatuses can adopt the content described in the following patents:

[0004] The first method, such as CN116609207A, uses a die to press the material specimen to achieve a tensile effect. However, the die is in close contact with the material, and the contact part is prone to large deformation, which generates a large friction force that affects the test results. On the other hand, the closed tensile device makes it difficult to directly measure the deformation displacement (strain) of the specimen under stress.

[0005] The second type, such as CN105043862A and CN117433892A, describes the isoaxial tensile testing apparatus for circular specimens. Currently, the testing machines used for isoaxial tensile testing of circular specimens employ multiple sets of motors or hydraulic cylinders to pull steel cables. These cables are connected to clamps, which then move radially to stretch the circular specimen. The traction force and speed of these multiple motors or hydraulic cylinders have inherent errors, making it difficult to ensure uniform stress on the circular specimen during the tensile process, thus compromising the accuracy of the isoaxial tensile test results. Furthermore, because some materials exhibit different mechanical properties in different directions (i.e., material anisotropy), and because specimen deformation can easily deviate during loading due to factors such as specimen processing quality and clamp fixing methods, inconsistent loads can easily occur during the tensile process, leading to the circular isoaxial tensile test failing to achieve the desired results.

[0006] The third method involves tensile testing of a cross-shaped biaxial arm specimen. The four arms of the specimen are held by a clamp, with the clamping position maintained at a certain distance from the central measurement area. This ensures that the stress within the measurement area of ​​the specimen is not affected by the lateral constraints of the clamp. The tensile device simultaneously stretches the cross-shaped specimen along both the X and Y axes in the XOY plane, obtaining stress-strain data of the central measurement area under the action of the biaxial tensile stress field.

[0007] Existing commercial biaxial testing machines are typically complex in structure and expensive, often operating as standalone testing equipment that cannot be integrated with existing universal testing machines, resulting in poor versatility. For example, the biaxial testing machine produced by ZwickRoell in Germany costs hundreds of thousands to millions of yuan, several times or even tens of times more than a uniaxial universal testing machine. It is equipped with multiple sets of electro-hydraulic cylinder-driven tensile units, an electronic control system, and a video extensometer system. Biaxial tensile mechanical property testing devices disclosed in patents such as CN206208651U cannot be combined with existing universal testing machines for testing, failing to effectively utilize readily available universal testing machines and increasing testing costs. Furthermore, biaxial testing machines suffer from drawbacks such as complex structure, increased failure rate, high price, and poor versatility.

[0008] For example, CN117681427A, CN111060397A, and CMMT(MN)054 are testing devices that use umbrella-shaped frames or scissor-type quadrilateral frames to achieve biaxial tensile testing on a uniaxial universal testing machine. Most of the load of the uniaxial universal testing machine is applied to the frame hinge joints, and a small portion is applied to the test specimen. It is not easy to change different sizes of fixtures due to the limitations of the frame size, and its application range is relatively limited.

[0009] For example, CN218726063U is a testing device that uses a linkage mechanism to achieve biaxial tensile testing on a uniaxial universal testing machine. Most of the load of the uniaxial universal testing machine is applied to the hinge position of the connecting plate and the linkage, and a small part is applied to the test specimen. It is not easy to change different sizes of fixtures due to the limitation of frame size. It requires the installation of additional force sensors, has a large number of parts and a complex structure, and is prone to generating more systematic errors. Utility Model Content

[0010] This application provides an elastic element stretching device to simplify the structure of the elastic element stretching device and improve the versatility of the device.

[0011] In a first aspect, embodiments of this application provide an elastic element tensioning device, which adopts the technical solution described below:

[0012] An elastic element stretching device is used to stretch an elastic element comprising N or fewer arms. The elastic element stretching device includes: a support frame, a guide motion assembly, a fixing assembly, a reversing assembly, a rigid pull rope, and a drive assembly. The guide motion assembly includes N sets of guide motion components, the fixing assembly includes N sets of fixing components, and the reversing assembly includes N sets of reversing components. Wherein, N is an integer greater than or equal to 2.

[0013] The guide motion assembly is fixed to the support frame; the N sets of guide motion components are respectively arranged corresponding to the stretching directions of the N arms of the elastic member; each set of guide motion components includes a guide part and a motion part that cooperate with each other;

[0014] Each set of fixing members is fixed to the moving part of a set of guide moving members; and each set of fixing members is used to fix one arm of the elastic member respectively;

[0015] Each set of the reversing components includes: a supporting reversing part and a moving reversing part; the moving reversing part is fixed to the moving part of the guiding moving part; the supporting reversing part is located at the end of the guiding moving part away from the elastic element and is fixed to the support frame;

[0016] Each group of reversing components corresponds to a group of guiding motion components; the rigid pull rope is wound around the N groups of reversing components to position and reverse the direction through the reversing components; the driving end of the driving component is driven and connected to the rigid pull rope, so that the driving component drives the corresponding guiding motion component to drive the fixed component to stretch or release the N arms of the elastic component through the cooperation of the rigid pull rope and the reversing component.

[0017] Furthermore, in one embodiment, the device further includes an image sensor;

[0018] The image sensor is fixedly mounted on a corresponding elastic element; the elastic element is an elastic element fixed behind the elastic element tensioning device.

[0019] Furthermore, in one embodiment, the support frame is arranged vertically or horizontally.

[0020] Furthermore, in one embodiment, a force gauge is provided at the axial position of the rigid pull rope, the reversing member, the motion guide, or the support frame corresponding to the axial position of the reversing member to measure the tension value applied to the elastic member or spring.

[0021] Furthermore, in one embodiment, the rigid pull rope is wound around the N sets of commutators; the drive end of the drive assembly is driven to connect with the rigid pull rope through the following structure:

[0022] A ring-shaped rigid pull rope is wound in a tensioned state around the N sets of commutators; the output end of the drive assembly is fixedly connected to the adapter; a set of commutators corresponding to the adapter also includes a transfer commutator; at least a portion of the transfer commutators are fixed to the adapter, and the drive assembly drives the adapter to move linearly, thereby driving the ring-shaped rigid pull rope, so as to realize the drive end of the drive assembly and the rigid pull rope drive connection.

[0023] Furthermore, in one embodiment, the switching commutator includes: a fourth commutation structure and a fifth commutation structure;

[0024] The fourth reversing structure is fixed to the adapter and is used to reverse the rigid pull rope so that it is perpendicular to the plane where the support frame is located.

[0025] The fifth reversing structure is disposed between the first and second reversing structures of the set of reversing members corresponding to the transition, and is used to reversing the rigid pull rope to be parallel to the plane where the support frame is located.

[0026] Furthermore, in one embodiment, the supporting commutation portion of each group of commutators includes a first commutation structure and a second commutation structure; the motion commutation portion includes a third commutation structure;

[0027] The first reversing structure, the second reversing structure, and the third reversing structure are arranged in a T-shape; wherein the first reversing structure and the second reversing structure are the horizontal sides of the T-shape; and the third reversing structure is the vertical side of the T-shape.

[0028] Furthermore, in one embodiment, the first reversing structure and the second reversing structure are fixed to the support frame by a transition block, so that the first reversing structure, the second reversing structure and the third reversing structure are located in the same plane.

[0029] Furthermore, in one embodiment, each set of the fasteners includes a base plate and a clamping plate disposed opposite each other; one arm of the elastic member is located between the base plate and the clamping plate;

[0030] A butterfly-shaped spring is provided on the side of the clamping plate away from the arm of the elastic member. The base plate, the clamping plate and the butterfly-shaped spring are sequentially and detachably clamped together to clamp one arm of the elastic member.

[0031] Furthermore, in one embodiment, the support frame includes: a support plate; the guide motion assembly and the support reversing portion are fixed to the support plate; and / or,

[0032] The moving parts of the N groups of guide moving parts are located in the same plane; and / or,

[0033] The N is equal to 2 or 4.

[0034] Compared with the prior art, the embodiments of this application have the following main advantages:

[0035] This application embodiment uses the unidirectional driving force output by the driving component to drive the rigid pull rope to drive the unidirectional / multidirectional guide component to transmit the driving force to the elastic element in a uniaxial / multiaxial manner. Based on the different requirements of various elastic elements for uniaxial / multiaxial tensile tests, the corresponding tensile purpose can be flexibly achieved on the basis of the same tensile device, which is more versatile and more convenient to achieve tensile test. In addition, the elastic element tensile device of this application embodiment has a simple structure, fewer types and numbers of parts, so the cost is low and maintenance is convenient. Attached Figure Description

[0036] To more clearly illustrate the solution of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 This is a schematic diagram of the overall structure of one embodiment of the elastic element tensioning device of this application with the support frame vertically arranged;

[0038] Figure 2 A schematic diagram of the overall structure of one embodiment of the elastic element tensioning device of this application with the support frame horizontally arranged;

[0039] Figure 3 for Figure 2 A partially enlarged schematic diagram of the elastic element tensioning device shown.

[0040] Figure 4 This is an enlarged exploded structural diagram of the guide moving part and the fixing part of the elastic element tensioning device of this application;

[0041] Figure 5 A magnified schematic diagram of the elastic element tensioning device of this application after an image sensor is installed;

[0042] Figure 6 A schematic diagram of a simplified mechanical model of the elastic element tensioning device of this application;

[0043] Figure 7 This is a schematic diagram of the structure of an embodiment of the equivalent mechanical model of the elastic element tensioning device of this application.

[0044] Reference numerals: 100 Elastic tensioning device; 200 Elastic element; 110 Support frame; 120 Guide motion component; 130 Fixing component; 140 Reversing component; 150 Rigid pull rope; 160 Drive assembly; 180 Adapter; 190 Force gauge; 121 Guide part; 122 Motion part; 131 Base plate; 132 Clamping plate; 133 Butterfly spring; 141 First pulley; 142 Second pulley; 143 Third pulley; 144 Fourth pulley; 145 Fifth pulley. Detailed Implementation

[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein in the specification of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "comprising" and "having," and any variations thereof, in the specification, claims, and foregoing drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the specification, claims, or foregoing drawings of this application are used to distinguish different objects, not to describe a particular order.

[0046] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0047] Unless otherwise defined, any description in this document of a structural component being "fixed to" or "fixedly connected to" another structural component includes methods of fixing such as prefabricating two structural components as a single unit or fixing them together via a centering member.

[0048] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings.

[0049] like Figures 1 to 3 As shown, Figure 1 This is a schematic diagram of the overall structure of one embodiment of the elastic element tensioning device of this application with the support frame vertically arranged; Figure 2 A schematic diagram of the overall structure of one embodiment of the elastic element tensioning device of this application with the support frame horizontally arranged; Figure 3 for Figure 2 The diagram shows a partially enlarged structural schematic of the elastic element tensioning device.

[0050] This application provides an elastic element stretching device 100 for stretching an elastic element 200 comprising N or fewer arms. The elastic element stretching device 100 includes: a support frame 110, a guide motion assembly, a fixing assembly, a reversing assembly, a rigid pull rope 150 (also referred to as "pull rope"), and a drive assembly 160.

[0051] The guiding motion assembly includes N sets of guiding motion components 120, the fixing assembly includes N sets of fixing components 130, and the reversing assembly includes N sets of reversing components 140; wherein, N is an integer greater than or equal to 2. In this embodiment, the number of each component can be adjusted according to the needs of the elastic element being stretched on the test axis.

[0052] It should be noted that, in order to achieve various preset axial tensions, elastic elements (e.g., made of elastic or hyperelastic materials) typically have arms formed at both ends of each tension axis for fixing to a fixed element. Taking uniaxial tension as an example, the elastic element is a linear structure, with each end of the linear elastic element being one of its two arms; taking biaxial tension as another example, the elastic element is usually a cross-shaped structure with two axes intersecting, and the four sides of the cross-shaped structure serve as the four arms of the elastic element.

[0053] In this application embodiment, the number of arms of the elastic element is less than or equal to N. For example, if N equals 4, the elastic element can have 2 arms or 4 arms (e.g., Figure 4 As shown in the diagram, this device can perform tensile tests on elastic elements with both two and four arms. When biaxial tensile testing of a cross-shaped elastic element is required, each of the four arms of the elastic element is fixed to one of the four corresponding fasteners. When uniaxial tensile testing of a linear elastic element with two arms is required, only two axially opposed fasteners need to be selected to fix one arm of the elastic element. No changes to the structure of the tensile device are needed, thus improving the versatility and ease of use of the entire elastic element tensile device.

[0054] For ease of understanding, the embodiments of this application are mainly described in detail using the following examples: the elastic element 200 includes 4 arms; the guiding motion assembly includes 4 sets of guiding motion elements; the fixing assembly includes 4 sets of fixing elements; and the pulley assembly includes 4 sets of pulley elements.

[0055] N sets of guide motion components 120 are fixed to the support frame 110, and the N sets of guide motion components are respectively set to correspond to the stretching direction of the N arms of the elastic component.

[0056] For example, taking a cross-shaped elastic member 200 including four arms as an example, the four sets of guide motion members are respectively distributed in a cross shape corresponding to the stretching direction of the four arms of the cross-shaped elastic member 200.

[0057] Specifically, the aforementioned support frame can adopt any structure and shape as needed. For example, such as... Figure 1 and 2 As shown, the support frame 110 includes a support plate.

[0058] The support frame 110 can be set at any angle as needed, for example: vertically (e.g.) Figure 1 As shown), horizontal settings (such as) Figure 2 (As shown). In a preferred embodiment, the support frame 110 is horizontally positioned, so that the tension in the single-axis Z-axis direction can be converted to the XOY plane by the reversing component, minimizing the effect of gravity on the tension.

[0059] It should be noted that the support frame, guide motion component, fixing component, and / or reversing component in the embodiments of this application can generally be made of any rigid material, such as resin materials like PEEK, POM, and bakelite, or metal materials like aluminum alloy and stainless steel. Specifically, they can be processed using methods such as 3D printing and CNC machining. The rigid pull rope can be any type of rope that is rigid and can withstand a certain amount of tension, such as stainless steel wire, UHMWPE ultra-high molecular weight polyethylene braided rope, nylon rope, etc.

[0060] In one embodiment, each set of guide motion components includes a guide portion 121 and a motion portion 122 that cooperate with each other. The guide motion component is fixed to the support frame 110 through the guide portion 121, for example, by fixing it with a centering component such as screws or glue, or it is prefabricated as a whole, for example, by directly forming a guide portion such as a groove on the support frame.

[0061] Specifically, each set of guiding motion components can be, but is not limited to, various existing or future-developed structural components that can provide guiding motion, such as guide rail slider structures, roller screw structures, roller belt structures, and sliding groove sliders. Typically, each set of guiding motion components has the same structure and specifications; however, different structures and specifications can also be used as needed. For ease of understanding, this application's embodiments mainly use four identical guide rail slider structures as an example for detailed explanation.

[0062] In a preferred embodiment, the N sets of guide motion elements are located in the same plane, which helps to achieve consistency in motion control in N directions, thereby facilitating the synchronous stretching of the cross-shaped elastic element in N directions based on the same drive; in addition, the N sets of guide motion elements may not be located in the same plane as needed, all of which are within the scope of protection of this application.

[0063] For example, such as Figure 1 and Figure 3As shown, the linear guide rails (i.e. guide portions 121) of the four identical guide motion members 120 are fixed in a cross shape to the flat support plate (i.e. support frame 110), and the slider (i.e. motion portion 122) can reciprocate along the guide rails based on the drive of the rigid pull rope 150 described in the later embodiment.

[0064] Each set of fasteners 130 is fixed to the moving part 122 of a corresponding set of guide moving parts, and is used to fix one arm of the elastic member 200 respectively.

[0065] Specifically, the clamps can be any structure of existing or future-developed arms capable of securing elastic elements, as needed. In tensile testing of elastomers, to ensure the stability of the specimen during testing and prevent slippage, different types of clamps can be used to secure the elastic element under tensile testing, as required. Some common clamp structures are listed below:

[0066] Manual clamps: This is the most basic type of clamp, in which the operator manually clamps the sample between the two clamping surfaces of the clamp.

[0067] Automatic clamps: Automatic clamps can automatically adjust the clamping force to accommodate samples of different widths and thicknesses.

[0068] Wedge clamps: These clamps use a wedge mechanism to increase clamping force and are suitable for tests that require greater clamping force.

[0069] Rotary clamps: Rotary clamps allow the specimen to rotate within the clamp, reducing errors caused by improper clamping.

[0070] Hydraulic clamps: Hydraulic clamps provide uniform and adjustable clamping force through a hydraulic system.

[0071] Pneumatic clamps: Pneumatic clamps use compressed air to control clamping force and are suitable for applications that require rapid clamping and release.

[0072] Spring clamps: These use the elastic force of springs to clamp samples. They are simple to operate and have a low cost.

[0073] Magnetic clamps: These clamps use magnetic force to hold the sample in place, making them particularly suitable for testing non-magnetic materials.

[0074] Clamping straps or clamping plates: In some cases, using clamping straps or clamping plates can provide a more even clamping force.

[0075] Specially designed fixtures: For specimens of specific materials or shapes, specially designed fixtures may be required to ensure the accuracy of the test.

[0076] Environmental control fixtures: When testing under high or low temperature conditions, environmental control fixtures can keep the sample stable at a specific temperature.

[0077] Non-contact fixtures: In some cases, non-contact fixtures may be used to avoid damaging the specimen or affecting the test results.

[0078] Adaptive clamps: These clamps can automatically adjust the clamping method according to the shape and size of the sample.

[0079] like Figure 4 As shown, Figure 4 This is an enlarged exploded structural diagram of the guide moving part and the fixing part of the elastic element tensioning device of this application.

[0080] In one embodiment, each set of fasteners 130 includes a base plate 131 and a clamping plate 132 disposed opposite to each other, one arm of the cross-shaped elastic member 200 is disposed between the base plate 131 and the clamping plate 132, and the base plate 131 and the clamping plate 132 are detachably clamped together to clamp one arm of the elastic member.

[0081] The embodiments of this application use a base plate and a clamping plate to detachably clamp the arm that clamps the elastic element. The structure is simple, the clamping is firm, and the replacement of the elastic element is convenient.

[0082] It should be noted that the aforementioned detachable clamping connection between the base plate and the clamping plate can adopt various existing or future-developed structures as needed. For example, the detachable clamping connection between the base plate and the clamping plate can be achieved by using screws, pins, or other centering components, or by the base plate and the clamping plate themselves forming mutually cooperating slots, tenon and mortise structures, etc.

[0083] Continue as Figure 4 As shown, in one embodiment, a butterfly spring 133 is provided on the side of the clamping plate 132 away from the elastic member 200. The base plate 131, clamping plate 132, and butterfly spring 133 are sequentially clamped and connected by screws or the like. By providing the butterfly spring 133, it can automatically clamp according to the clamping thickness (the thickness will become thinner when the sample is stretched), thereby enabling the elastic member to be clamped better under any tensile strength.

[0084] It should be noted that usually the N sets of fasteners have the same structure; in addition, different structures can be used as needed.

[0085] Each set of reversing components 140 includes: a supporting reversing part and a moving reversing part: the moving reversing part is fixed to the moving part 122 of the corresponding guide moving part 120 (e.g., directly fixed to the moving part or fixed to the moving part by a central structure such as a fixing member); the supporting reversing part is located at the end of the guide moving part 120 away from the elastic member 200 and is fixed to the support frame 110 (e.g., directly fixed to the support frame or fixed to the support frame by a central member such as a guide part).

[0086] Specifically, the reversing components can be various structural parts that can change the direction and position of the rigid pull rope, such as pulleys, block structures, etc. For ease of understanding, this application mainly uses pulleys as an example of the reversing structure for detailed explanation. The number and arrangement of the reversing components can be arbitrarily set as needed, as long as they can change the direction of the rigid pull rope, so that the rigid pull rope is set roughly along the movement direction of each guide moving part, so that the pull rope drives each moving part to move along the guide part, all of which fall within the scope of protection of this application.

[0087] For ease of understanding, the embodiments of this application will be described in detail using pulleys as the reversing component.

[0088] Specifically, the number of pulleys included in each set of reversing components can be arbitrarily set as needed. For example, such as Figure 4 As shown, in one embodiment, at least part of the reversing component includes a first pulley 141 (i.e., a first reversing structure), a second pulley 142 (i.e., a second reversing structure), and a third pulley 143 (i.e., a third reversing structure). The supporting reversing portion includes the first pulley 141 and the second pulley 142; the moving reversing portion includes the third pulley 143; the first pulley 141 and the second pulley 142 are symmetrically arranged on the horizontal side of the T-shape; the third pulley 143 is located on the vertical side of the T-shape. The third pulley 143 is fixed to the end of the moving portion 122 of the guiding moving component that is away from the fixed elastic member 200.

[0089] In one embodiment, the first pulley 141 and the second pulley 142 can be fixed to the support frame by an adapter block, so that the first pulley 141, the second pulley 142 and the third pulley 143 are located in the same plane.

[0090] In this embodiment, the rigid pull rope can be directed and limited to the direction of movement substantially along the moving part by means of the first pulley, the second pulley and the third sliding engagement.

[0091] It should be noted that, in order to achieve effective reversing of the rigid tension rope, in addition to the specific structures of each set of reversing components described above, each set of reversing components may be arranged with other structural forms as needed, or more or fewer reversing structures may be set, all of which fall within the scope of protection of this application.

[0092] Each set of commutator 140 corresponds to a set of guide motion components 120; they are arranged around N sets of commutator 140 to position and change direction through the commutator 140; the drive end of the drive assembly is connected to the rigid pull rope drive, so that the drive assembly drives the corresponding guide motion component to drive the fixed component to stretch or release the N arms of the elastic component through the cooperation of the rigid pull rope and the commutator.

[0093] Each set of reversing members 140 is provided with a set of guide motion members 120. Rigid pull ropes 150 are wound around N sets of reversing members 140 so that the reversing members 140 can be used to position and change direction. The direction of the rigid pull rope can be limited to the same or approximately the same direction as the movement direction of the corresponding guide motion member, and to the same or parallel plane as the plane where the guide motion member is located. This allows the rigid pull ropes 150 to effectively drive the movement part 122 of the guide motion member to move in the direction defined by the guide part 121.

[0094] It should be noted that the embodiments of this application can employ various existing or future-developed drive components capable of driving the tensioning and loosening motion of the pull rope. For example, a uniaxial tensile testing machine (uniaxial universal testing machine) can be used as the drive component (e.g., Figure 1 and Figure 2 (as shown); or it could be a rotary motor, linear motor, cylinder, hydraulic cylinder, or other power source or structural components including the above power sources.

[0095] Specifically, for the aforementioned "drive connection," various structural methods can be adopted as needed. As long as the drive component can drive the rigid pull rope, it falls within the scope of protection of this application. For example, one end of a non-loop rigid pull rope is connected to the output end of a linear drive component, and the other end is connected to a fixed end, so that the pull rope can be stretched or released by the drive component.

[0096] Continue as Figure 2 and Figure 3 As shown, in another embodiment, the above-mentioned "rigid pull rope is wound around N sets of commutators" and "the drive end of the drive assembly is driven connected to the rigid pull rope" can be achieved through the following structure:

[0097] A ring-shaped rigid pull rope is wound in a tensioned state around N sets of commutator 140; the output end of the drive assembly 160 is fixedly connected to the adapter 180; a set of commutator corresponding to the adapter 180 also includes a transfer commutator; at least part of the transfer commutator is fixed to the adapter 180 so that the drive assembly 160 drives the adapter 180 to move linearly, thereby driving the rigid pull rope 150, so as to realize the above-mentioned "drive end of the drive assembly is driven to connect with the rigid pull rope".

[0098] In one embodiment, the aforementioned switching mechanism may include a fourth pulley 144 (i.e., the fourth switching structure) and a fifth pulley 145 (i.e., the fifth switching structure).

[0099] The fourth pulley 144 is fixed to the adapter 180 and is used to change the direction of the rigid pull rope to be perpendicular to the plane where the support frame 110 is located, so as to achieve the above-mentioned "at least part of the adapter is fixed to the adapter".

[0100] The fifth pulley is located between the first pulley 141 and the second pulley 142 of a set of reversing members corresponding to the adapter 180, and is used to reverse the rigid pull rope to be parallel to the plane XOY where the support frame is located.

[0101] In this embodiment, the output end of the drive assembly 160 moves upward along the Z-axis. It can drive the fourth pulley 144 via the adapter 180, thereby causing the tensioned pull rope 150 to stretch. The rigid pull rope 150 is arranged around the reversing member 140 for positioning and reversing via the reversing member 140. Driven by the drive assembly 160 and positioned by the reversing member 140, the rigid pull rope 150 drives the corresponding guide motion member 120 to stretch or release the N arms of the elastic member via the fixing member 130. This allows the single-axis output end of the linearly driven structure to drive the adapter 180 in single-axis up-down movement. Through the cooperation of the ring-shaped rigid pull rope and various reversing members, single-axis / multi-axis stretching and relaxation of the elastic member can be achieved. This design is highly versatile, simple in structure, and low in cost.

[0102] In this embodiment, by using a tension rope and various reversing components to coordinate the loading of the load, the device can automatically ensure that the forces applied in two axial directions / four directions are equal, since the tension on the rope is equal everywhere, which is convenient to use and reduces costs.

[0103] This application, by using the unidirectional driving force output by the drive component, and based on the reversing of each group of reversing components, can drive the rigid pull rope to drive the unidirectional / multidirectional guide components to transmit the driving force to the elastic component in a uniaxial / multiaxial manner. Based on the different requirements of various elastic components for uniaxial / multiaxial tensile tests, the corresponding tensile purpose can be flexibly achieved on the basis of the same tensile device, which is more versatile and more convenient to achieve tensile testing. In addition, compared with the existing spoke-arranged electric cylinder-steel cable structure, scissor frame structure, and umbrella structure, the elastic component tensile device of this application embodiment has a simple structure, fewer types and numbers of parts, thus lower cost and convenient maintenance.

[0104] like Figure 5 As shown, Figure 5 A magnified schematic diagram of the elastic element tensioning device of this application after an image sensor has been installed.

[0105] In one embodiment, the present application also includes an image sensor 170.

[0106] The image sensor 170 is fixedly mounted to the elastic element 200 of the device 100.

[0107] Typically, the image sensor 170 lens needs to be positioned directly opposite the center of the elastic member 200; however, it may not be positioned directly opposite the center depending on the actual situation, and both are within the scope of this application.

[0108] Specifically, the image sensor can be fixed to the support frame, or it can be fixed to any desired location outside the support frame, all of which fall within the scope of protection of this application.

[0109] The image sensor 170 is communicatively connected to the controller (omitted in the figure).

[0110] In one embodiment, an image sensor is used to acquire images of the elastic element before the middle portion of the elastic element is stretched, and images of the elastic element after the middle portion is stretched, respectively; and,

[0111] It is also used to acquire images of the spring before it is stretched, and images of the spring after it is stretched, respectively, of the spring before the middle part of the spring is stretched, and images of the spring after the middle part of the spring is stretched; wherein, the middle part of the elastic element and the spring are respectively marked.

[0112] A controller is configured to identify a first deformation of the mark based on images of the elastic element before and after stretching, and a second deformation of the mark based on images of the spring before and after stretching.

[0113] In one embodiment, the controller is also used to identify the strain of the elastic element based on the first deformation.

[0114] To make it easier to understand, the above process will be explained in more detail below using an elastic element as an example:

[0115] Step 210 Specimen Marking: Mark the surface of the elastic element in advance (e.g., print or spray a specific pattern or marking point), and the initial distance between these marking points is defined as the original gauge length L0.

[0116] Step 220 Image Acquisition: At the beginning of the experiment, an image sensor is used to photograph the elastic element to capture an image of the elastic element before it is stretched in an unstressed state.

[0117] Step 230 Image Processing and Feature Recognition: The controller uses image processing algorithms to identify markers in the image. The exact location of these markers in the image is determined.

[0118] Step 240 Deformation Tracking: When the elastic element is subjected to tensile or compressive forces, the markings on the elastic element move as the material deforms. The image sensor captures these changes in real time.

[0119] Step 250 Deformation Calculation: By comparing the positional changes of the marks before and after the tension, the deformation between the marks is calculated. This deformation is the actual deformation ΔT of the elastic element.

[0120] Step 260 Strain Calculation: Strain (ε) is defined as the relative change in the length of the material and can be calculated using the following formula: ε = Δε / ε0 = (L(t) - L0) / L0 where L(t) is the length between the marked points at time t, Δε is the deformation of the mark, and ε0 is the original gauge length.

[0121] This application embodiment uses an image sensor to capture images of the deformation and displacement of the central measurement area of ​​the elastic member under tensile force. This allows for a more accurate calculation of the strain (ε) of the elastic member under tension. In practical applications of hyperelastic materials / rubber materials, biaxial tensile testing can more accurately obtain the changes in the mechanical properties of materials under complex loads. The stress-strain data combination measured under biaxial tensile stress can be used to more accurately fit the parameters of the material constitutive relation (strain energy density function).

[0122] In one embodiment, a force sensor (e.g., a tension or strain gauge) can be installed along the rigid tension rope, the corresponding tension position of the reversing member, or the axial position of the corresponding reversing member of the motion guide or support frame. For ease of understanding, further explanation is provided below:

[0123] Continue as Figure 3 As shown, in one embodiment, in order to obtain the force applied by the drive component to the rigid pull rope more accurately, a force gauge 190 can be set along the rigid pull rope at any suitable location to directly measure the tension of the pull rope, which can then be used as the tension value applied to the elastic element 200 or the spring.

[0124] In one embodiment, a force gauge can be installed at any position of the pull rope corresponding to any reversing member (not shown due to obstruction). For example, a force gauge can be installed axially (e.g., in the center hole or shaft) of any pulley (e.g., the third pulley 143) or with the force gauge as the central axis (figure omitted) to indirectly measure the tension of the pull rope, which is then used as the tension value applied to the elastic member 200 or the spring.

[0125] In one embodiment, a force sensor may also be provided at the axial position of the motion guide or support frame corresponding to the fixed reversing member. For example, a force sensor may be provided at the position where the third pulley 143 is fixed in the motion part 122; or a force sensor may be provided at the protrusion formed by the first pulley 141 and the second pulley 142 fixed in the support frame 110, so as to indirectly measure the tension value applied to the elastic member 200 or the spring.

[0126] In this embodiment, the force on the pull rope is transmitted to the central shaft of the pulley, and then to the block structure to which the pulley is fixed. The force measuring device has a certain volume and shape, and it is not easy to install it at the central hole / shaft position of the pulley. Installing the force measuring device on the block structure along the axial direction of the pulley can also achieve the purpose of indirectly measuring the tension of the pull rope under the force of the pulley, and use it as the tension value applied to the elastic element 200 or the spring.

[0127] In this embodiment, by setting a force measuring device along the rigid pull rope, the corresponding tension position of the reversing member, or the motion guide or the fixed part of the support frame that fixes the reversing member, the force value can be obtained closer to the elastic member. This reduces the error caused by the force lost due to friction with the pulley during the transmission of the force output by the drive component through the pull rope. The measured force is closer to the actual tension value of the elastic member, and is used as the tension value applied to the elastic member 200 or the spring.

[0128] In one embodiment, in addition to setting a force sensor along the motion guide or fixed part of the support frame of the rigid pull rope, reversing member, or fixed reversing member as described above, a force sensor built into the drive assembly itself can also be used as the tension value applied to the elastic member 200 or the spring. However, compared with the method described in the above embodiment, some error loss is ignored, so the accuracy of the obtained tension value will be relatively reduced.

[0129] Based on the elastic element tensioning device described in the above embodiments, this application also provides an elastic element tensioning system (figures omitted).

[0130] The system includes the tensioning device 100 for the elastic element and the controller described in the above embodiment.

[0131] The controller and the drive components communicate with each other via wired or wireless means.

[0132] In one embodiment, based on the above embodiments, when the stretching device of the elastic element includes an image sensor, the controller is also connected to the image sensor via a wired or wireless means.

[0133] Specifically, the controller can generate program instructions based on a pre-defined program and data signals collected from external drive components, image sensors, etc. Limitations on the controller can be found in the following embodiments regarding the methods for determining the stiffness of the elastic element and / or calculating the tensile error of the elastic element.

[0134] It should be noted that the aforementioned wireless connection methods may include, but are not limited to, 3G / 4G / 5G connections, WiFi connections, Bluetooth connections, WiMAX connections, Zigbee connections, UWB (ultra wideband) connections, and other currently known or future wireless connection methods.

[0135] The controller provided in this application embodiment may be, but is not limited to, a computer terminal (PC); an industrial personal computer (IPC); a mobile terminal; a server; a system including a terminal and a server, implemented through interaction between the terminal and the server; a programmable logic controller (PLC); a field-programmable gate array (FPGA); a digital signal processor (DSP) or microcontroller unit (MCU), or similar controllers. Specifically, the controller may be a computer device.

[0136] It should be noted that the controller described in the embodiments of this application can be set up separately, or it can be partially or wholly integrated into devices such as elastic element tensioning device and / or image sensor, all of which fall within the scope of protection of this application.

[0137] Obviously, the embodiments described above are only some embodiments of this application, not all embodiments. The accompanying drawings show preferred embodiments of this application, but do not limit the patent scope of this application. This application can be implemented in many different forms; rather, the purpose of providing these embodiments is to provide a more thorough and comprehensive understanding of the disclosure of this application. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing specific embodiments, or make equivalent substitutions for some of the technical features. Any equivalent structures made using the content of this application's specification and drawings, directly or indirectly applied to other related technical fields, are similarly within the scope of patent protection of this application.

Claims

1. An elastic element stretching device for stretching an elastic element comprising N or fewer arms, characterized in that, The elastic element tensioning device includes: a support frame, a guide motion assembly, a fixing assembly, a reversing assembly, a rigid pull rope, and a drive assembly; the guide motion assembly includes N sets of guide motion components, the fixing assembly includes N sets of fixing components, and the reversing assembly includes N sets of reversing components; wherein, N is an integer greater than or equal to 2. The guide motion assembly is fixed to the support frame; the N sets of guide motion components are respectively arranged corresponding to the stretching directions of the N arms of the elastic member; each set of guide motion components includes a guide part and a motion part that cooperate with each other; Each set of fixing members is fixed to the moving part of a set of guide moving members; and each set of fixing members is used to fix one arm of the elastic member respectively; Each set of the reversing components includes: a supporting reversing part and a moving reversing part; the moving reversing part is fixed to the moving part of the guiding moving part; the supporting reversing part is located at the end of the guiding moving part away from the elastic element and is fixed to the support frame; Each group of reversing components corresponds to a group of guiding motion components; the rigid pull rope is wound around the N groups of reversing components to position and reverse the direction through the reversing components; the driving end of the driving component is driven to the rigid pull rope, so that the driving component drives the corresponding guiding motion component to drive the fixed component to stretch or release the N arms of the elastic component through the cooperation of the rigid pull rope and the reversing component.

2. The elastic element tensioning device according to claim 1, characterized in that, The device also includes an image sensor; The image sensor is fixedly mounted on a corresponding elastic element; the elastic element is an elastic element fixed behind the elastic element tensioning device.

3. The elastic element tensioning device according to claim 1 or 2, characterized in that, The support frame can be set vertically or horizontally.

4. The elastic element tensioning device according to claim 1 or 2, characterized in that, A force measuring device is installed at the axial position of the rigid pull rope, the reversing component, the motion guide, or the support frame corresponding to the reversing component, to measure the tension applied to the elastic component or spring.

5. The elastic element tensioning device according to claim 1 or 2, characterized in that, The rigid pull rope is wound around the N sets of commutators; the drive end of the drive assembly is connected to the rigid pull rope via the following structure: A ring-shaped rigid pull rope is wound in a tensioned state around the N sets of commutators; the output end of the drive assembly is fixedly connected to the adapter; a set of commutators corresponding to the adapter also includes a transfer commutator; at least a portion of the transfer commutators are fixed to the adapter, and the drive assembly drives the adapter to move linearly, thereby driving the ring-shaped rigid pull rope, so as to realize the drive end of the drive assembly and the rigid pull rope drive connection.

6. The elastic element tensioning device according to claim 5, characterized in that, The switching component includes: a fourth switching structure and a fifth switching structure; The fourth reversing structure is fixed to the adapter and is used to reverse the rigid pull rope so that it is perpendicular to the plane where the support frame is located. The fifth reversing structure is disposed between the first and second reversing structures of the set of reversing members corresponding to the transition, and is used to reversing the rigid pull rope to be parallel to the plane where the support frame is located.

7. The elastic element tensioning device according to claim 1 or 2, characterized in that, Each set of commutator support commutator includes a first commutator structure and a second commutator structure; the motion commutator includes a third commutator structure; The first reversing structure, the second reversing structure, and the third reversing structure are arranged in a T-shape; wherein the first reversing structure and the second reversing structure are the horizontal sides of the T-shape; and the third reversing structure is the vertical side of the T-shape.

8. The elastic element tensioning device according to claim 1 or 2, characterized in that, The first reversing structure and the second reversing structure are fixed to the support frame by a transition block, so that the first reversing structure, the second reversing structure and the third reversing structure are located in the same plane.

9. The elastic element tensioning device according to claim 1 or 2, characterized in that, Each set of fasteners includes a base plate and a clamping plate disposed opposite each other; one arm of the elastic member is located between the base plate and the clamping plate; A butterfly-shaped spring is provided on the side of the clamping plate away from the arm of the elastic member. The base plate, the clamping plate and the butterfly-shaped spring are sequentially and detachably clamped together to clamp one arm of the elastic member.

10. The elastic element tensioning device according to claim 1 or 2, characterized in that, The support frame includes: a support plate; the guide motion assembly and the support reversing part are fixed to the support plate; and / or... The moving parts of the N groups of guide moving parts are located in the same plane; and / or, The N is equal to 2 or 4.

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