A hair cover rigidity constraint test method and device

Abstract

The present application relates to a kind of hair cover rigidity restraint test method and device, method includes hair cover surface rigidity-instability and hair cover surface rigidity-anti-concave restraint working condition, hair cover lateral rigidity, hair cover torsional rigidity-intermediate restraint restraint working condition, hair cover torsional rigidity-edge restraint restraint working condition and hair cover hinge fixed point rigidity restraint working condition test, this test method can all hair cover rigidity test using same set of tool test restraint method is restrained, this method six tests of same hair cover classification is divided into four different restraint working conditions, the same classification of different models hair cover can be measured rigidity value by one of the four restraint working conditions;Different models of hair cover and same model hair cover can reach same restraint standard under different classification test projects, so that the restraint condition is closer to the requirement of test standard, so that the test precision is higher, CAE analysis and test restraint system are more easily matched, and work efficiency is higher.

Description

Technical Field

[0001] This invention belongs to the field of automotive technology, specifically relating to a method and apparatus for testing the stiffness constraint of a hood. Background Technology

[0002] Automotive hood stiffness testing involves measuring the stiffness values ​​at various points on the hood under different stress conditions to ensure its safety and quality during use. The same hood stiffness test is divided into six categories: hood surface stiffness - instability, hood surface stiffness - dent resistance, hood lateral stiffness, hood torsional stiffness - intermediate constraint, hood torsional stiffness - edge constraint, and hood hinge fixation point stiffness.

[0003] However, in existing testing processes, the constraint devices used for measuring the stiffness values ​​of various types of hairnets and different categories of the same hairnet are not entirely the same, and the constraint process is difficult and cumbersome. This ultimately leads to deviations in the test results, and also causes a large discrepancy between the CAE analysis results and the test results, making it impossible to accurately measure and evaluate the stiffness value of the hairnet. At the same time, it also reduces work efficiency and wastes a lot of human resources. Summary of the Invention

[0004] The purpose of this invention is to provide a method for testing the stiffness constraint of a hair shield, and also to provide a device for testing the stiffness constraint of a hair shield, so as to solve the problem of improving test accuracy and the unification of CAE analysis and test constraint system by unifying the hair shield constraint method, and to use the same set of tooling test constraint method to constrain the stiffness of all hair shields.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] A method for testing the stiffness constraint of a hairnet includes the following steps:

[0007] A. Hair cover surface stiffness - instability and hair cover surface stiffness - indentation resistance constraint conditions

[0008] A1. Determine the fixed position of the square column with hinge constraint assembly on the side of the hairnet hinge. Use the L-shaped hinge constraint clamp to constrain the hinge and fix the clamp at an appropriate height position of the square column.

[0009] A2. Fix the hair cover locking ring using the hair cover front restraint assembly - hair cover locking ring support fixing column assembly, and adjust the height of the hair cover locking ring support column so that the bottom edge of the locking ring is at the same height as the hinge mounting surface;

[0010] A3. Using the front-end constraint assembly of the hood—the two hood front-end main buffer block support fixing column assemblies support the position of the buffer blocks, constrain the position of the buffer blocks to a degree of freedom of 3; adjust the angle and position of the support columns to be directly below the hood front-end main buffer block; measure the deformation of the hood and calculate the stiffness value of the hood.

[0011] B. Lateral stiffness and torsional stiffness of the hair cover - intermediate constraint conditions

[0012] B1. Determine the fixed position of the square column with hinge constraint assembly on the side of the hairnet hinge. Use the L-shaped hinge constraint fixture to constrain the hinge and fix the fixture at an appropriate height position of the square column.

[0013] B2. Use the front restraint assembly of the hair cover - hair cover lock ring support and fixing column assembly to support the lower edge of the hair cover lock ring in the Z direction, and adjust the height of the hair cover lock ring support column so that the bottom edge of the lock ring is at the same height as the hinge mounting surface;

[0014] B3. The locking ring is clamped by a fixture to constrain the position of the buffer block to degree 3; the angle and position of the support column assembly are adjusted to achieve the angle position that does not interfere with the loading of the loading cylinder; the displacement of the hood is measured laterally on the hood surface and the stiffness value of the hood is calculated.

[0015] C. Torsional stiffness of the hairnet - edge constraint condition

[0016] C1. Determine the fixed position of the square column with hinge constraint assembly on the side of the hairnet hinge, use the L-shaped hinge constraint fixture to constrain the hinge, and fix the fixture at an appropriate height of the square column.

[0017] C2. Use one of the support columns of the main buffer block support fixing column assembly at the front end of the hair cover to support the main buffer block on one side of the hair cover. Adjust the length and height of the upper and lower screws of the support column so that the bottom edge of the locking ring is at the same height as the hinge mounting surface.

[0018] C3. Constrain the position of the buffer block to degree 3; lower the height of the hair cover locking ring support column, adjust the main buffer block support column at the front end of the other hair cover to be directly below the main buffer block on the other side, so that the bottom edge of the locking ring is at the same height as the hinge mounting surface, and keep the hair cover horizontal in the Y direction; manually rotate the upper screw of the main buffer block support column at the front end of one side of the hair cover at a uniform speed, so that the screw moves downward, and measure the deformation of the hair cover at the outer plate of the hair cover surface corresponding to the lowered main buffer block;

[0019] D. Stiffness constraint condition at the hinge fixing point of the hair cover

[0020] D1. Determine the fixed position of the square column with hinge constraint assembly on the hairnet hinge side; remove the test side hinge, and use an L-shaped hinge constraint fixture to constrain the non-test side hinge, and fix the fixture at an appropriate height of the square column.

[0021] D2. On the test side, the square hole surface of the square hole on the round surface of the square hole in the hair cover hinge side constraint assembly without the hinge constraint assembly is connected to the square column, and one end is connected to the multi-joint direction conversion adjustment fixing arm. The front end of the fixing arm clamps the X / Y sides of the hair cover on the test hinge side.

[0022] D3. Fix the hair cover locking ring using the front constraint assembly of the hair cover—the hair cover locking ring support fixing column assembly. Adjust the height of the hair cover locking ring support column so that the bottom edge of the locking ring is at the same height as the hinge mounting surface. Adjust the angle and position of the support column to achieve an angle position that does not interfere with the loading of the loading cylinder. Connect the two fixing holes of the hinge through the clamp and measure the deformation of the hair cover.

[0023] Furthermore, in steps A1, B1, C1, and D1, the position is determined so that the telescopic arm of the loading cylinder can reach the range of all test categories of the hairnet, and the fixture is fixed at the optimal height so that the loading cylinder can perform stiffness tests above and below the hairnet.

[0024] Further, in step A3, adjust the telescopic arm on the main buffer block support fixing column assembly at the front end of the hair cover so that the angle and position of the support column are directly below the main buffer block at the front end of the hair cover. Adjust the length of the upper and lower screws of the support column so that the lower end contacts the ground for fixation, and the upper end is supported by a φ20 steel ball between itself and the installation position of the buffer block. Load the hair cover at the measurement point by the loading cylinder and measure the deformation of the hair cover using a displacement sensor.

[0025] Further, in step B3, the clamping surface and the upper surface of the hair cover locking ring support column are supported by φ20 steel balls; the telescopic arm on the main buffer block support fixing column assembly at the front end of the hair cover is adjusted so that the angle and position of the support column assembly reach the angle position that does not interfere with the loading cylinder; the length of the upper and lower screws of the support column is adjusted so that the lower end is off the ground and the upper end avoids contact with the hair cover; the hair cover locking ring is laterally loaded by the loading cylinder, and the displacement sensor is used to measure the displacement of the hair cover laterally on the surface of the hair cover.

[0026] Further, in step C2, adjust the length of the upper and lower lead screws of the support column so that the lower end contacts the ground for fixation, and the upper end is supported by a φ20 steel ball between itself and the installation position of the buffer block.

[0027] Further, in step C3, reduce the height of the hairnet locking ring support column so that the height of the support column does not interfere with the test standard; adjust the length of the upper and lower screws of the support column so that the lower end contacts the ground for fixation, and the upper end is supported by a φ20 steel ball between it and the installation position of the buffer block; manually rotate the upper screw of the main buffer block support column at one side of the hairnet at a uniform speed so that the screw moves downward.

[0028] Further, in step D3, adjust the telescopic arm on the main buffer block support fixing column assembly at the front end of the hair cover so that the angle and position of the support column do not interfere with the loading cylinder. Adjust the length of the upper and lower screws of the support column so that the lower end is off the ground and the upper end avoids contact with the hair cover. Use the loading cylinder to apply downward load at the middle position of the two holes and use the displacement sensor to measure the deformation of the hair cover.

[0029] A hairpiece stiffness constraint device comprises a hairpiece front end constraint assembly and a hairpiece hinge side constraint assembly; the hairpiece front end constraint assembly includes a hairpiece locking ring support fixing column assembly and two hairpiece front end main buffer block support fixing column assemblies; the hairpiece hinge side constraint assembly includes a hairpiece hinge side constraint assembly with hinge and a hairpiece hinge side constraint assembly without hinge.

[0030] The hairnet locking ring support fixing column assembly consists of a support column fixed to the ground, a support screw, a locking flange, a locking ring pressure plate, and a locking ring pressure plate fixing pin. The top of the support screw is welded to a locking ring support platform, and the support platform is connected to the locking ring pressure plate through the locking ring pressure plate fixing pin. The locking flange can lock and position the screw and the support column to the opposite position when the support screw is rotated to meet the test height requirements.

[0031] The main buffer block support and fixing column assembly at the front end of the hair cover is composed of a lower telescopic fixing screw, an upper telescopic support screw, a screw connecting rod, a locking flange, and a telescopic rod. The lower telescopic fixing screw is used to fix the main buffer block support and fixing column assembly at the front end to the ground. The lower telescopic fixing screw and the screw connecting rod cooperate with each other and are welded to the upper telescopic support screw. The locking flange is used to lock the screws when the lower telescopic fixing screw and the upper telescopic support screw are screwed to the fixed and support positions. The ring of the telescopic rod is fitted onto the support column of the hair cover locking ring support and fixing column assembly.

[0032] The hinge side restraint assembly of the hair cover - with hinge restraint assembly, consists of two parts: a column fixed to the ground and an L-shaped hinge restraint clamp fixed to the column;

[0033] The hair cover hinge side constraint assembly - without hinge constraint assembly, consists of a column, a square hole upper round surface clamp, and a multi-joint direction conversion adjustment fixing arm; the square hole upper round surface clamp can be inserted into the column and fixed at any position at the column height; the multi-joint direction conversion adjustment fixing arm is used to realize the adjustment of degrees of freedom 123456, and to constrain the edge of the hair cover on the hinge side without the hair cover.

[0034] Furthermore, the hinge-side constraint assembly of the hood is shared with the column in the hinge-side constraint assembly of the hood.

[0035] Furthermore, the multi-joint direction conversion adjustment and fixing arm consists of a first-order rotating arm, a second-order clamping plate, a third-order telescopic rotating arm, and a fourth-order rotating plate. The two elongated holes on the first-order rotating arm are used in conjunction with the second-order clamping plate. The circular hole chuck of the second-order clamping plate is used in conjunction with the third-order telescopic rotating arm. The cylinder on the third-order telescopic rotating arm can be rotated and its position adjusted up and down in the circular hole chuck of the second-order clamping plate. When the position reaches the test constraint position, the circular hole chuck of the second-order clamping plate can be locked. One end of the fourth-order rotating plate consists of two symmetrical rotating disks, and the disk of the third-order telescopic rotating arm is located in the middle of the two disks. When rotated to the test constraint position, the position can be fixed by using the elongated holes on the rotating disks and the bolt holes on the disks of the third-order telescopic rotating arm.

[0036] Compared with the prior art, the beneficial effects of the present invention are:

[0037] This invention provides a method for constraining the stiffness of a hairpiece, enabling the use of the same set of tooling and testing constraints for all hairpiece stiffness tests. This method categorizes the six test types of the same hairpiece into four different constraint conditions. Hairpieces of different models within the same category can have their stiffness values ​​measured using one of these four constraint conditions. This ensures that hairpieces of different models, as well as hairpieces of the same model, meet the same constraint standards under different test categories, making the constraint conditions closer to the test standard requirements, increasing test accuracy, facilitating the matching of CAE analysis and the test constraint system, and improving work efficiency. Attached Figure Description

[0038] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 Hair cover lock ring support fixing column assembly structure;

[0040] Figure 2 The main buffer block support and fixing column assembly structure at the front end of the head cover;

[0041] Figure 3 Hair shield hinge side restraint assembly - structure with hinge restraint assembly;

[0042] Figure 4Hair shield hinge side restraint assembly - structure without hinge restraint assembly;

[0043] Figure 5 Overall structure of the hood restraint assembly. Detailed Implementation

[0044] The present invention will be further described below with reference to embodiments:

[0045] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0046] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this invention, terms such as "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0047] This invention improves experimental accuracy and unifies CAE analysis with experimental constraint systems by standardizing the hair shield constraint methods. Hair shield stiffness tests can be categorized into six types: hair shield surface stiffness-instability test, hair shield surface stiffness-indentation resistance test, hair shield lateral stiffness test, hair shield torsional stiffness-intermediate constraint test, hair shield torsional stiffness-edge constraint test, and hair shield hinge fixing point stiffness test.

[0048] I. Classification of Constrained Operating Conditions

[0049] This invention further divides the above six types of hair cover stiffness tests into four test constraint conditions based on different constraint methods: hair cover surface stiffness - instability, hair cover surface stiffness - anti-dent constraint condition; hair cover lateral stiffness, hair cover torsional stiffness - intermediate constraint condition; hair cover torsional stiffness - edge constraint condition; and hair cover hinge fixing point stiffness constraint condition.

[0050] The stiffness test classification for different models of hoods can be achieved by measuring the stiffness value through one of the four constraint conditions. This ensures the uniformity of constraint test methods and equipment for different models of hoods, avoids the influence of differences in test constraint methods and equipment on test results, improves the cost-effectiveness of CAE analysis, and also achieves the comparability of test results.

[0051] II. Determination of Each Constraint Assembly

[0052] In the test method for stiffness constraint of the hood, the constraint body is designed as two sub-assemblies, namely the front constraint assembly of the hood and the hinge side constraint assembly of the hood.

[0053] 1. Front-end restraint assembly of the headlight cover

[0054] The front-end constraint assembly of the hood mainly consists of the hood locking ring support and fixing column assembly and two hood front-end main buffer block support and fixing column assemblies, which are used to realize all the constraint functions required for the front end of the hood in the hood stiffness test.

[0055] The conditions that the front end of the hairnet needs to meet in the experiment are: to enable the loading cylinder to load at the bottom of the hairnet. Therefore, the fixing column needs to be designed to be more than one meter high to fully meet the space requirements for the loading cylinder to use under the hairnet, and it should not be too high to facilitate operation when loading on the upper surface of the hairnet.

[0056] Because there are three points requiring constraint on the front end of the hairnet during the entire hairnet stiffness test—the hairnet locking ring, the two main buffer blocks on the left and right sides of the front end—the front end constraint assembly is designed as a single unit. This single-unit structural design ensures the consistency of tooling used in different hairnet tests. Furthermore, to accommodate different test categories for the same hairnet and ensure that the front end main buffer block support and fixing column assembly does not interfere with the lower space of the hairnet during various tests, the two front end main buffer block support and fixing column assemblies are designed to be telescopic and foldable.

[0057] All front-end support and fixing column assemblies are height-adjustable within a certain range, facilitating Z-axis position adjustment during hairnet installation. The front-end main buffer block support and fixing column assembly of the hairnet is height-adjustable at both ends; the upper end allows for Z-axis height adjustment for easy hairnet installation, while the lower end allows for Z-axis retraction adjustment when the restraint column is folded or fixed. The front-end restraint assembly of the hairnet uses the hairnet locking ring support and fixing column assembly as the primary component and the two front-end main buffer block support and fixing column assemblies as secondary components, forming a front-end restraint scheme.

[0058] 2. Hood hinge side restraint assembly

[0059] Since the crown hinges are used symmetrically on both ends, two hinge-side constraint assemblies are designed. These two assemblies are functionally identical and symmetrically positioned. Because the six test categories for crown stiffness testing are divided into those with hinges and those without, the constraint assemblies for both categories are designed as a single large assembly in the crown hinge-side constraint assembly design. This facilitates rapid adjustment and switching of the constraint device between test categories.

[0060] 21. Hinge-side constraint assembly under the category of hinges

[0061] The main structure uses square columns, with a height sufficient for the combined use of the hood and front restraint assembly under test conditions. M12 bolt holes are evenly distributed on the four sides of the square column to facilitate the fixing of the hinges and hood restraint fixtures. Next is the design of the hinge restraint fixture. Since hinge fixing methods can be divided into XY plane (or XY plane with an angle) and XZ plane (or XY plane fixing holes with an angle), the hinge restraint fixture is designed as an L-shaped hinge restraint fixture, and two side hinge fixing plates are welded to the two sides of the L-shaped fixture. Therefore, Method 1 involves fixing one side of the L-shaped fixture to the square column and the other side to the XY plane hinge; Method 2 involves fixing one side of the L-shaped fixture to the square column, and the side welded plates of the L-shaped fixture to the XZ plane hinge. The fixing devices for the left and right hinges are identical, and their installation positions are symmetrical about the X-axis of the hood.

[0062] 22. Assembly without hinge restraint

[0063] Hinge-side constraint assembly without hinge classification:

[0064] The main structure uses a square column, which is the same square column used in the hinge-side constraint assembly tooling for hinged applications. A square-hole type upper circular surface fixture is installed on the square column. The square hole mates with the square column and can be fixed at any position in the Z-direction of the square column's fixing hole, used for Z-direction height adjustment of the fixture. The upper circular surface of the square-hole type upper circular surface fixture is used to install a multi-joint direction conversion adjustment fixing arm, which can achieve six degrees of freedom adjustment. The fixing arm is used to fix the hair cover without hinges. An identical set of multi-joint direction conversion adjustment fixing arms is installed on each of the left and right sides of the circular surface of the square-hole type upper circular surface fixture to meet the hair cover fixing requirements of the test. It fixes the hair cover edges in the X and Y directions of the hinge side of the hair cover without hinges. Since the hair cover edges have inherent angles, and these angles and shapes vary, the designed fixing arms must be adjustable in six angles to meet the requirements for fixing different hair cover edges.

[0065] Third, by coordinating the various constraint assemblies mentioned above, the four test conditions of the hood are achieved, and finally, the tests on the hood in six different categories are completed, forming a set of overall test constraint methods.

[0066] Working condition 1: Hair cover surface stiffness-instability and hair cover surface stiffness-indentation resistance constraint working condition.

[0067] These two types of tests use the same constraint method for the hood, differing only in the test points for the hood's stiffness value. Therefore, these two tests are categorized under the same test condition. The constraint scheme for this condition involves constraining the hood hinge to degrees of freedom 1, 2, 3, 4, 5, and 6, the locking ring to degrees of freedom 1, 2, 3, 4, 5, and 6, and the main buffer block at the front of the hood to degree 3. The constraint method is to constrain the bottom edge of the locking ring to be at the same height as the hinge mounting surface. Degrees of freedom 1, 2, 3, 4, 5, and 6 represent the X, Y, Z directions, X-axis rotation, Y-axis rotation, and Z-axis rotation, respectively.

[0068] First, determine the fixed position of the hinge-side constraint assembly for the hood—the square column with the hinge constraint assembly. The position should be determined so that the extension arm of the loading cylinder can reach within the range for testing all test categories of the hood. Use an L-shaped hinge constraint fixture to constrain the hinge, and fix the fixture at an appropriate height for the square column. The optimal height is such that the loading cylinder can perform stiffness tests both above and below the hood.

[0069] Secondly, the hair cover locking ring is fixed by using the front restraint assembly of the hair cover - the hair cover locking ring support fixing column assembly, and the height of the hair cover locking ring support column is adjusted so that the bottom edge of the locking ring is at the same height as the hinge mounting surface.

[0070] Finally, the position of the buffer blocks is constrained by the front-end constraint assembly of the hood—two main buffer block support and fixing column assemblies at the front end of the hood—to achieve a constraint on the buffer block's positional degree of freedom (3 degrees of freedom). The telescopic arms on the main buffer block support and fixing column assembly at the front end of the hood are adjusted so that the angle and position of the support columns are directly below the main buffer blocks at the front end of the hood. The lengths of the upper and lower lead screws of the support columns are adjusted so that the lower end contacts the ground for fixation, while the upper end is supported by φ20 steel balls between itself and the buffer block's installation position. Load is applied to the hood's measurement points using a loading cylinder, and the deformation of the hood is measured using a displacement sensor. Finally, the stiffness value of the hood is calculated. This is the test scheme for the constraint conditions of hood surface stiffness-instability and hood surface stiffness-indentation resistance.

[0071] Working condition 2: Transverse stiffness and torsional stiffness of the hair cover - intermediate constraint working condition.

[0072] These two types of tests use the same constraint method for the hair shield, differing only in the definition of hair shield stiffness measurement. Therefore, these two tests are classified into the same test condition. The constraint scheme for this condition involves constraining the hair shield hinge to degrees of freedom 1, 2, 3, 4, 5, and 6, and the locking ring to degree of freedom 3. The constraint method is to constrain the bottom edge of the locking ring to be at the same height as the hinge mounting surface.

[0073] First, determine the fixed position of the hinge-side constraint assembly for the hood—the square column with the hinge constraint assembly. The position should be determined so that the extension arm of the loading cylinder can reach within the range for testing all test categories of the hood. Use an L-shaped hinge constraint fixture to constrain the hinge, and fix the fixture at an appropriate height for the square column. The optimal height is such that the loading cylinder can perform stiffness tests both above and below the hood.

[0074] Secondly, the lower edge of the hair cover lock ring is supported in the Z direction by using the hair cover front restraint assembly—the hair cover lock ring support fixing column assembly, and the height of the hair cover lock ring support column is adjusted so that the bottom edge of the lock ring is at the same height as the hinge mounting surface.

[0075] The locking ring is held in place by a clamp, with the clamping surface supported by a φ20 steel ball on the upper surface of the headgear locking ring support column. The position of the buffer block is constrained by 3 degrees of freedom. The telescopic arm on the main buffer block support fixing column assembly at the front end of the headgear is adjusted so that the angle and position of the support column assembly do not interfere with the loading cylinder's loading. The lengths of the upper and lower lead screws of the support column are adjusted so that the lower end is off the ground and the upper end avoids contact with the headgear. Lateral loading is applied to the headgear locking ring using the loading cylinder. The displacement of the headgear is measured laterally on the headgear surface using a displacement sensor, and the headgear stiffness value is finally calculated. This is the test scheme for the headgear's lateral stiffness constraint condition. If the loading cylinder is used to load the outer plate position corresponding to one side of the main buffer block, and the headgear displacement is measured at the lower buffer block position using a displacement sensor, this is the test scheme for the headgear's torsional stiffness - intermediate constraint condition.

[0076] Working condition 3: Torsional stiffness of the cover - edge constraint working condition.

[0077] The constraint scheme for this working condition is to constrain the degrees of freedom of the hood hinge (1, 2, 3, 4, 5, 6) and the degree of freedom of the main buffer block on one side (3). The constraint method is to constrain the bottom edge of the locking ring to be at the same height as the hinge mounting surface.

[0078] First, determine the fixed position of the hinge-side constraint assembly for the hood—the square column with the hinge constraint assembly. The position should be determined so that the extension arm of the loading cylinder can reach within the range for testing all test categories of the hood. Use an L-shaped hinge constraint fixture to constrain the hinge, and fix the fixture at an appropriate height for the square column. The optimal height is such that the loading cylinder can perform stiffness tests both above and below the hood.

[0079] Secondly, one of the support columns of the main buffer block support fixing column assembly at the front end of the hair cover is used to support the main buffer block on one side of the hair cover. The length of the upper and lower screws of the support column is adjusted so that the lower end contacts the ground for fixation, and the upper end is supported by a φ20 steel ball between the upper end and the installation position of the buffer block. The height is such that the bottom edge of the locking ring is at the same height as the hinge mounting surface.

[0080] Constraining the buffer block's positional degree of freedom (DOF 3) is implemented. The height of the hairnet locking ring support column is lowered to ensure the support column height does not interfere with the test. The telescopic arm on the main buffer block support column at the front of the other side of the hairnet is adjusted so that it is directly below the other main buffer block. The lengths of the upper and lower lead screws of the support column are adjusted so that the lower end contacts the ground for fixation, and the upper end is supported by a φ20 steel ball between it and the buffer block installation position. The height is such that the bottom edge of the locking ring is at the same height as the hinge mounting surface, and the hairnet remains horizontal in the Y direction. The upper lead screw of the main buffer block support column at the front of one side of the hairnet is manually rotated at a uniform speed, causing the lead screw to move downwards. The deformation of the hairnet is measured at the outer plate of the hairnet surface corresponding to the lowered main buffer block. This is the test scheme for the hairnet's torsional stiffness under edge constraint conditions.

[0081] Working condition 4: Stiffness constraint of the hinge fixing point of the hair cover.

[0082] The constraint scheme for this working condition is to constrain the hinge on the non-test side of the hood to degrees of freedom 123456, the locking ring position to degrees of freedom 123456, and the two edges of the hood on the test side to degrees of freedom 123456. The constraint method is to constrain the bottom edge of the locking ring to be at the same height as the hinge mounting surface.

[0083] First, determine the fixed position of the hinge-side constraint assembly for the hood—the square column with the hinge constraint assembly. The position should be determined so that the extension arm of the loading cylinder can reach within the range for testing all test categories of the hood. Remove the test-side hinge, and use an L-shaped hinge constraint fixture to constrain the non-test-side hinge. Fix the fixture at an appropriate height on the square column, ideally so that the loading cylinder can perform stiffness tests above and below the hood.

[0084] Secondly, on the test side, the square hole surface of the square hole on the round surface of the hair cover hinge side constraint assembly—without the hinge constraint assembly—is connected to the square column, and one end is connected to the multi-joint direction conversion adjustment fixing arm. The front end of the fixing arm clamps the X / Y sides of the hair cover on the test hinge side.

[0085] The hair shield locking ring is fixed using the front-end constraint assembly—the hair shield locking ring support fixing column assembly. The height of the hair shield locking ring support column is adjusted so that the bottom edge of the locking ring is at the same height as the hinge mounting surface. The telescopic arm on the front-end main buffer block support fixing column assembly is adjusted so that the angle and position of the support column do not interfere with the loading cylinder. The lengths of the upper and lower lead screws of the support column are adjusted so that the lower end is off the ground and the upper end does not contact the hair shield. Finally, the two fixing holes of the hinge are connected by a clamp, and the loading cylinder is used to apply downward load at the middle position between the two holes. The deformation of the hair shield is measured using a displacement sensor. This is the test scheme for the stiffness constraint condition of the hair shield hinge fixing point.

[0086] Example 1

[0087] A hairpiece stiffness constraint device includes a hairpiece front-end constraint assembly and a hairpiece hinge-side constraint assembly. The hairpiece front-end constraint assembly mainly consists of a hairpiece locking ring support and fixing column assembly and two hairpiece front-end main buffer block support and fixing column assemblies.

[0088] like Figure 1 As shown, the hairnet locking ring support and fixing column assembly mainly consists of five parts: support column, support screw, locking flange, locking ring pressure plate, and locking ring pressure plate fixing pin.

[0089] The support column provides the assembly with a fixed position and supports the lifting space of the lead screw. The support column base is made of 360x360x30 steel plate and is used to connect to the ground during support. An inner lead screw cylinder with an outer diameter of 120mm and a height of 1 meter is welded to the upper end of the base. The bottom of the cylinder is connected to the base with reinforcing ribs in four directions. A circular limiting platform with a height of 20mm and a thickness of 20mm is machined at a position 600mm above the bottom edge of the cylinder. Its purpose is to limit the height of the telescopic rod in the main buffer block support and fixing column assembly of the headlight cover. The support screw has a diameter of 50mm and a length that can be set within the range of 400mm-800mm, which is sufficient for the testing requirements. A locking ring support platform is welded to the top of the screw. A quarter-inch M8 groove is machined laterally in the center of the platform to facilitate the positioning of the locking ring and provide clamping space for the locking ring clamping plate. The platform is 60mm wide, 150mm long, and 20mm thick, accommodating all locking ring widths, and its thickness provides sufficient clamping rigidity. One end of the platform has an M8 elongated hole for clamping with the elongated hole in the locking ring clamping plate; the other end has a U-shaped opening, 30mm wide, with a transversely machined M8 through hole. This part connects the support platform and the locking ring clamping plate using a locking ring clamping plate fixing pin. The locking flange's function is to lock and position the screw and support column when the support screw is rotated to the required testing height. The locking ring pressure plate is connected to the locking ring support platform at the upper end of the support screw via a locking ring pressure plate fixing pin. It is 20mm wide and 15mm thick, allowing it to pass through the interior of all locking rings. It is 150mm long, with an M8 elongated hole machined at one end for locking with the screw support platform, and a quarter-inch M8 groove machined in the center, corresponding to the groove on the locking ring support platform at the top of the screw. The other end is machined into an L-shape, with a fixing hole for the locking ring pressure plate fixing pin. When the fixing pin connects the locking ring pressure plate and the locking ring support platform welded to the top of the screw, there is no obvious gap between the contact surfaces when they are horizontal. Therefore, when the locking ring is between them, the side with the elongated hole will tilt upwards, allowing bolts to be used to clamp the locking ring. The above describes the dimensions and functions of each part of the designed hairnet locking ring support fixing column.

[0090] The method of using the hair cover lock ring support fixing column assembly is as follows: When using it, move the hair cover lock ring support fixing column assembly directly below the lock ring, insert the lock ring pressure plate into the lock ring so that the bottom edge of the lock ring is clamped in the groove, tighten the lock ring pressure plate to the lock ring support platform at the top of the screw with bolts, and finally fix the support column base to the ground.

[0091] like Figure 2 As shown, the main buffer block support and fixing column assembly at the front end of the hair cover is mainly composed of five parts: lower telescopic fixing screw, upper telescopic support screw, screw connecting rod, locking flange, and telescopic rod 2.

[0092] The lower telescopic fixed screw consists of a lower fixed disc with a diameter of φ100mm and a thickness of 30mm, providing sufficient rigidity. Its main function is to fix the front main buffer block support column assembly to the ground. A screw with an outer diameter of 50mm and a length of 500mm is welded onto the disc. The lower telescopic fixed screw cooperates with the screw connecting rod to provide telescopic and height adjustment. The upper telescopic support screw has a length of 500mm and an outer diameter of 50mm. It cooperates with the screw connecting rod to provide telescopic support. The screw connecting rod is a cylindrical shape with an outer diameter of φ90mm and a length of 500mm. The inner threaded hole cooperates with the lower telescopic fixed screw and the upper telescopic support screw to connect the screws and provide telescopic functionality. A square tubular telescopic rod 1 with a length of 400mm is welded in the middle of the connecting rod. A groove with a width of 13mm and a length of 380mm is machined in the middle of the telescopic rod for the telescopic sliding of the connecting rod. There are two locking flanges, whose function is to lock the screws when the lower telescopic fixed screw and the upper telescopic support screw are screwed to the fixed and support positions, ensuring that the relative positions of the screws and connecting rods remain unchanged during the test. The square tube telescopic rod 2 is 400mm long, with a 13mm wide and 380mm long sliding groove machined in the middle. The diameter of the inner square hole of the telescopic rod 2 is slightly larger than the outer diameter of the square tube of the telescopic rod 1. A ring with a diameter of 121mm and a width equal to half the thickness of the telescopic rod is welded to one end. The telescopic rod 1 is inserted into the telescopic rod 2, the sliding groove is inserted into the pin, and the ring is inserted into the support column of the hair cover lock ring support and fixing column assembly. At this time, the limiting platform on the support column of the hair cover lock ring support and fixing column assembly will limit its height from the bottom edge. In this position, the lower telescopic fixing screw and the upper telescopic support screw are simultaneously screwed into the screw connecting rod by 1 / 2 dimension. The bottom surface of the lower fixed disc of the lower telescopic fixing screw will be higher than the bottom surface of the front support fixing column assembly of the hair cover, and the top of the upper telescopic support screw will be lower than the top of the hair cover locking ring support fixing column assembly at its lowest dimension. This allows for the cooperation between the front main buffer block support fixing column assembly of the hair cover and the hair cover locking ring support fixing column, enabling adjustment of angle and length. Two sets of the same assembly are machined, and the rings on the telescopic rod 2 are interlocked to ensure that the telescopic rods on both sides reach the same height. The telescopic length of the telescopic rod can cover the width dimensions of all the front main buffer blocks of the hair cover.

[0093] The method of using the main buffer block support and fixing column assembly at the front end of the hair cover is as follows: When in use, the main body uses the telescopic rod's extension and retraction and the rotation function around the locking ring support and fixing column to adjust it to be directly below the main buffer blocks on both sides of the hair cover locking ring. Rotate the lower telescopic fixing screw downwards to make it contact the ground, and finally fix it to the ground; rotate the upper telescopic support screw upwards to support the position of the hair cover buffer block.

[0094] The hair cover hinge side constraint assembly includes a hair cover hinge side constraint assembly with hinge constraint assembly and a hair cover hinge side constraint assembly without hinge constraint assembly.

[0095] like Figure 3 As shown, the hood hinge side constraint assembly - with hinge constraint assembly mainly consists of two parts: a square column and an L-shaped hinge constraint fixture. It is composed of two sets of tooling assemblies with the same left and right hinges.

[0096] The square column measures 200x200x1500 mm with a wall thickness of 20 mm, ensuring its height and strength meet test requirements. M12 threaded holes are evenly distributed on the four sides of the column, with a horizontal and Z-axis spacing of 100 mm, used for fixing tooling fixtures. A 500x500x30 mm steel plate is welded to the bottom of the column for fixing it to the ground. The L-shaped hinge constraint fixture is designed in an L-shape, with an upper surface measuring 200x200x20 mm. The front end of the upper surface has a 10 mm wide and 150 mm long elongated hole, 15 mm from the front end, used for fixing the front mounting holes for the XY plane hinges. Behind the horizontal elongated hole are seven vertically evenly distributed elongated holes, each 10 mm wide and 145 mm long, used for installing the rear mounting holes for the XY plane hinges. The lower surface of the L-shaped fixture measures 220 x 200 x 20 mm. Two elongated holes, 13 mm wide and 150 mm long, spaced 100 mm apart, are machined on this surface. The hole length ensures that each hole can accommodate two bolts at any position on the square column. The spacing between the two elongated holes is approximately equal to the width of the horizontal bolt holes on the square column. At the lower end of the upper surface of the L-shaped hinge constraint fixture, two steel plates, 200 x 60 x 20 mm long, are welded to both sides. Elongated holes, 10 mm wide and 45 mm long, 15 mm from the outer edge, are machined along the Z-axis at the front of these plates to accommodate the front fixing holes for the hinges on the XZ-plane. A horizontally 10 mm wide and 150 mm long elongated hole is machined in the middle of the vertical holes to accommodate the rear fixing holes for the hinges on the XZ-plane. Hinges mounted on the XZ side are usually installed on the inside of the L-shaped hinge constraint fixture. Welding the same steel plate to both sides of the L-shaped hinge constraint fixture is for ease of installation, so that there is no need to distinguish between the left and right fixtures and to avoid installation errors.

[0097] The method of using the hairnet hinge side constraint assembly is as follows: Fix the square column base within the test area, ensuring that the loading cylinder can reach all test positions of the hairnet; fix the L-shaped hinge constraint fixture to the corresponding surface of the loading cylinder on the square column, ensuring that the loading cylinder can easily perform loading tests on both the top and bottom surfaces of the hairnet after installation; connect and fix the hairnet hinge to one fixed surface of the L-shaped hinge constraint fixture. The other hinge is installed in the same way.

[0098] like Figure 4As shown, the hairnet hinge-side constraint assembly – without hinges – mainly consists of a square column, a square-hole upper circular surface clamp, and a multi-joint direction conversion adjustment fixing arm. The square column is shared with the square column in the hairnet hinge-side constraint assembly – with hinges – thus improving the convenience of switching between constraint conditions. The square-hole upper circular surface clamp has a square-hole fixed surface underneath, with four sides that can be fixed to the four sides of the square column. The internal dimensions of its square hole are 201 x 201 mm, and the wall thickness is 20 mm. On each fixed surface of the square column, there are elongated holes spaced 100 mm apart, each 13 mm wide and 150 mm long. The spacing of these elongated holes is the same as the width spacing of the fixing holes on the square column. The square-hole upper circular surface clamp is fitted into the square column, and the fixing holes allow the clamp to be fixed at any position within the height of the square column. When not in use, it can be lowered to the bottom of the square column, thus avoiding interference with other test conditions. A square-hole disc is welded to the upper end of the square-hole fixing surface. The size of the square hole in the center of the disc is the same as the size of the square hole on the fixing surface. The disc is φ250mm in diameter and 20mm thick. Two semi-circular elongated holes are machined on the disc, with a 50mm distance between the two ends. The semi-circular elongated holes are 15mm from the outer circle and 13mm wide. M12 bolt holes are also machined 40mm from each side of the square hole. The circular clamp on the square hole is mainly used to connect the square column and the multi-joint direction-changing adjustment fixing arm. The multi-joint direction-changing adjustment fixing arm consists of four parts. Its function is to achieve adjustment of degrees of freedom 1, 2, 3, 4, 5, and 6, providing sufficient strength to constrain the edge of the hair cover on the hinge side without the hair cover. It consists of a first-stage rotating arm, a second-stage clamping disc, a third-stage telescopic rotating arm, and a fourth-stage rotating plate. The first-stage rotating arm is a square rod with dimensions of 400X60X40. A 13mm round hole is machined at one end of the 40mm wide face, and a 13mm wide elongated hole is machined on the same face. The round hole is connected to the M12 bolt hole on the round surface of the square hole fixture, and the elongated hole is connected to the semi-circular elongated hole on the round surface fixture of the square hole. The length of the elongated hole on the 40mm wide face of the first-stage rotating arm must meet the requirement that, with the M12 fixing hole as the rotation center, its length can reach the farthest end and the closest end of the semi-circular hole on the round surface fixture of the square hole from the M12 bolt hole. On the 60mm high face of the first-stage rotating arm, two elongated holes with a spacing of 30mm, a width of 13mm, a length of 250mm, and a distance of 20mm from one end opposite to the round hole are machined. Two elongated holes on the 60mm high surface of the first-stage rotating arm are used in conjunction with the second-stage clamping plate. The base of the clamping plate is a φ100mm thick disc with a semi-circular elongated hole machined on it to fix it to the first-stage elongated hole. At the same time, it can realize the function of rotating the disc and moving it to a fixed position along the first-stage rotating arm. A chuck with a 30mm diameter opening is welded on the disc.The second-stage clamping disc's circular hole chuck engages with the third-stage telescopic rotating arm. The rotating arm is a φ30mm, 200mm long cylinder, with a φ100mm, 20mm thick disc welded to one end. M12 bolt holes are evenly distributed on the disc, 10mm from the outer circle. The cylinder on the third-stage telescopic rotating arm can rotate and be adjusted vertically within the second-stage clamping disc's circular hole chuck. When the position reaches the test constraint position, the second-stage clamping disc's circular hole chuck is locked. The fourth-stage rotating plate has two symmetrical rotating disks at one end, with a 21mm gap between them. Both disks have elongated semi-circular holes. Between the two disks is a disk for a third-stage telescopic rotating arm. When rotated to the test constraint position, the elongated holes on the rotating disks and the bolt holes on the third-stage telescopic rotating arm disk can be used for position fixation. A 120x100x15mm fixing plate is welded to the front of the two disks. The front of the fixing plate has a 13mm wide, 70mm long, and 30mm long elongated hole at the top, and multiple vertical elongated holes are machined behind this hole. When the fixing plate is aligned with the edge of the hairnet, a pressure plate can be used to clamp and constrain the hairnet using the elongated holes on the fixing plate. The multi-joint direction-conversion adjusting fixing arm has a set of round clamps on each side of the square hole on the square column relative to the hairnet installation position. These are used to constrain the hairnet edges in the X and Y directions on the side without hinges. The above describes the functional composition of the various parts of the hood hinge side constraint assembly - without hinge constraint assembly.

[0099] The overall structure of the shield constraint assembly is shown in Figure 5. The arrangement of each component of the shield constraint assembly is as follows: the tooling on both sides of the shield hinge side constraint assembly is the same, and they are symmetrically arranged relative to the shield neutral line. Regardless of the constraint conditions selected for the left and right hinges, tests can be conducted quickly, improving the convenience of the test. Simply place the various positions of the shield requiring constraint according to the constraint conditions at the constraint positions to perform the shield stiffness test.

[0100] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A method for testing the stiffness constraint of a hairnet, characterized in that, Includes the following steps: A. Hair cover surface stiffness - instability and hair cover surface stiffness - indentation resistance constraint conditions A1. Determine the fixed position of the square column with hinge constraint assembly on the side of the hairnet hinge. Use the L-shaped hinge constraint clamp to constrain the hinge and fix the clamp at an appropriate height position of the square column. A2. Fix the hair cover locking ring using the hair cover front restraint assembly - hair cover locking ring support fixing column assembly, and adjust the height of the hair cover locking ring support column so that the bottom edge of the locking ring is at the same height as the hinge mounting surface; A3. Using the front-end constraint assembly of the hood—the two hood front-end main buffer block support fixing column assemblies support the position of the buffer blocks, constrain the position of the buffer blocks to a degree of freedom of 3; adjust the angle and position of the support columns to be directly below the hood front-end main buffer block; measure the deformation of the hood and calculate the stiffness value of the hood. B. Lateral stiffness and torsional stiffness of the hair cover - intermediate constraint conditions B1. Determine the fixed position of the square column with hinge constraint assembly on the side of the hairnet hinge. Use the L-shaped hinge constraint fixture to constrain the hinge and fix the fixture at an appropriate height position of the square column. B2. Use the front restraint assembly of the hair cover - hair cover lock ring support and fixing column assembly to support the lower edge of the hair cover lock ring in the Z direction, and adjust the height of the hair cover lock ring support column so that the bottom edge of the lock ring is at the same height as the hinge mounting surface; B3. The locking ring is clamped by a fixture to constrain the position of the buffer block to degree 3; the angle and position of the support column assembly are adjusted to achieve the angle position that does not interfere with the loading of the loading cylinder; the displacement of the hood is measured laterally on the hood surface and the stiffness value of the hood is calculated. C. Torsional stiffness of the hairnet - edge constraint condition C1. Determine the fixed position of the square column with hinge constraint assembly on the side of the hairnet hinge, use the L-shaped hinge constraint fixture to constrain the hinge, and fix the fixture at an appropriate height of the square column. C2. Use one of the support columns of the main buffer block support fixing column assembly at the front end of the hair cover to support the main buffer block on one side of the hair cover. Adjust the length and height of the upper and lower screws of the support column so that the bottom edge of the locking ring is at the same height as the hinge mounting surface. C3. Constrain the position of the buffer block to degree 3; lower the height of the hair cover locking ring support column, adjust the main buffer block support column at the front end of the other hair cover to be directly below the main buffer block on the other side, so that the bottom edge of the locking ring is at the same height as the hinge mounting surface, and keep the hair cover horizontal in the Y direction; manually rotate the upper screw of the main buffer block support column at the front end of one side of the hair cover at a uniform speed, so that the screw moves downward, and measure the deformation of the hair cover at the outer plate of the hair cover surface corresponding to the lowered main buffer block; D. Stiffness constraint condition at the hinge fixing point of the hair cover D1. Determine the fixed position of the square column with hinge constraint assembly on the hairnet hinge side; remove the test side hinge, and use an L-shaped hinge constraint fixture to constrain the non-test side hinge, and fix the fixture at an appropriate height of the square column. D2. On the test side, the square hole surface of the square hole on the round surface of the square hole in the hair cover hinge side constraint assembly without the hinge constraint assembly is connected to the square column, and one end is connected to the multi-joint direction conversion adjustment fixing arm. The front end of the fixing arm clamps the X / Y sides of the hair cover on the test hinge side. D3. Fix the hair cover locking ring using the front constraint assembly of the hair cover—the hair cover locking ring support fixing column assembly. Adjust the height of the hair cover locking ring support column so that the bottom edge of the locking ring is at the same height as the hinge mounting surface. Adjust the angle and position of the support column to achieve an angle position that does not interfere with the loading of the loading cylinder. Connect the two fixing holes of the hinge through the clamp and measure the deformation of the hair cover.

2. The hairpiece stiffness constraint test method according to claim 1, characterized in that: In steps A1, B1, C1, and D1, the location is determined so that the extension arm of the loading cylinder can reach the range of all test categories of the hairnet, and the fixture is fixed at the optimal height so that the loading cylinder can perform stiffness tests above and below the hairnet.

3. The method for testing the stiffness constraint of a hairnet according to claim 1, characterized in that: Step A3: Adjust the telescopic arm on the main buffer block support fixing column assembly at the front of the hair cover so that the angle and position of the support column are directly below the main buffer block at the front of the hair cover. Adjust the length of the upper and lower screws of the support column so that the lower end contacts the ground for fixation, and the upper end is supported by a φ20 steel ball between itself and the installation position of the buffer block. Load the hair cover at the measurement point through the loading cylinder and measure the deformation of the hair cover using a displacement sensor.

4. The hairpiece stiffness constraint test method according to claim 1, characterized in that: Step B3: The clamping surface and the upper surface of the hair cover locking ring support column are supported by φ20 steel balls; adjust the telescopic arm on the main buffer block support fixing column assembly at the front end of the hair cover so that the angle and position of the support column assembly are such that they do not interfere with the loading cylinder; adjust the length of the upper and lower screws of the support column so that the lower end is off the ground and the upper end is not in contact with the hair cover; apply lateral loading to the hair cover locking ring through the loading cylinder, and use a displacement sensor to measure the lateral displacement of the hair cover on the surface of the hair cover.

5. The hairpiece stiffness constraint test method according to claim 1, characterized in that: Step C2: Adjust the length of the upper and lower lead screws of the support column so that the lower end contacts the ground for fixation, and the upper end is supported by a φ20 steel ball between itself and the installation position of the buffer block.

6. The hairpiece stiffness constraint test method according to claim 1, characterized in that: Step C3: Lower the height of the hairnet locking ring support column to ensure that the height of the support column does not interfere with the test standard; adjust the length of the upper and lower screws of the support column so that the lower end contacts the ground for fixation, and the upper end is supported by a φ20 steel ball between it and the installation position of the buffer block; manually rotate the upper screw of the main buffer block support column at one side of the hairnet at a uniform speed to make the screw move downward.

7. The hairpiece stiffness constraint test method according to claim 1, characterized in that: Step D3: Adjust the telescopic arm on the main buffer block support fixing column assembly at the front end of the hair cover so that the angle and position of the support column do not interfere with the loading cylinder. Adjust the length of the upper and lower screws of the support column so that the lower end is off the ground and the upper end does not contact the hair cover. Use the loading cylinder to apply downward load at the middle position between the two holes and use the displacement sensor to measure the deformation of the hair cover.

8. A hairnet stiffness constraint device, characterized in that: It consists of a front-end constraint assembly for the hair cover and a hinge-side constraint assembly for the hair cover; the front-end constraint assembly for the hair cover includes a hair cover locking ring support and fixing column assembly and two front-end main buffer block support and fixing column assemblies for the hair cover; the hinge-side constraint assembly for the hair cover includes a hinge-side constraint assembly for the hair cover - with hinge constraint assembly and a hinge-side constraint assembly for the hair cover - without hinge constraint assembly. The hairnet locking ring support fixing column assembly consists of a support column fixed to the ground, a support screw, a locking flange, a locking ring pressure plate, and a locking ring pressure plate fixing pin. The top of the support screw is welded to a locking ring support platform, and the support platform is connected to the locking ring pressure plate through the locking ring pressure plate fixing pin. The locking flange can lock and position the screw and the support column to the opposite position when the support screw is rotated to meet the test height requirements. The main buffer block support and fixing column assembly at the front end of the hair cover is composed of a lower telescopic fixing screw, an upper telescopic support screw, a screw connecting rod, a locking flange, and a telescopic rod. The lower telescopic fixing screw is used to fix the main buffer block support and fixing column assembly at the front end to the ground. The lower telescopic fixing screw and the screw connecting rod cooperate with each other and are welded to the upper telescopic support screw. The locking flange is used to lock the screws when the lower telescopic fixing screw and the upper telescopic support screw are screwed to the fixed and support positions. The ring of the telescopic rod is fitted onto the support column of the hair cover locking ring support and fixing column assembly. The hinge side restraint assembly of the hair cover - with hinge restraint assembly, consists of two parts: a column fixed to the ground and an L-shaped hinge restraint clamp fixed to the column; The hair cover hinge side constraint assembly - without hinge constraint assembly, consists of a column, a square hole upper round surface clamp, and a multi-joint direction conversion adjustment fixing arm; the square hole upper round surface clamp can be inserted into the column and fixed at any position at the column height; the multi-joint direction conversion adjustment fixing arm is used to realize the adjustment of degrees of freedom 123456, and to constrain the edge of the hair cover on the hinge side without the hair cover.

9. A hairpiece stiffness constraint device according to claim 8, characterized in that: The hinge side restraint assembly with hinge is shared with the column in the hinge side restraint assembly with hinge.

10. A hairpiece stiffness constraint device according to claim 8, characterized in that: The multi-joint direction conversion adjustment and fixing arm consists of a first-order rotating arm, a second-order clamping plate, a third-order telescopic rotating arm, and a fourth-order rotating plate. The two elongated holes on the first-order rotating arm are used in conjunction with the second-order clamping plate. The circular hole chuck of the second-order clamping plate is used in conjunction with the third-order telescopic rotating arm. The cylinder on the third-order telescopic rotating arm can be rotated and its position adjusted up and down in the circular hole chuck of the second-order clamping plate. When the position reaches the test constraint position, the circular hole chuck of the second-order clamping plate can be locked. One end of the fourth-order rotating plate has two symmetrical rotating disks, and the disk of the third-order telescopic rotating arm is located in the middle of the two disks. When rotated to the test constraint position, the position can be fixed by using the elongated holes on the rotating disks and the bolt holes on the disks of the third-order telescopic rotating arm.

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