Chair back tipping performance test method

Abstract

The invention discloses a chair back tipping performance testing method, and belongs to the technical field of chair testing. The method comprises the steps that in the chair back tipping process, the pressure M alpha generated by a tested person naturally leaning against a chair back to the chair back and the supporting force m alpha generated by the chair back to the tested person are obtained; calculating to obtain an index for representing the human body comfort when the chair back tilts: X alpha = m alpha-M alpha, calculating to obtain an index for representing the supporting stability of the tested person in the chair back tilting process: # imgabs0 #, S represents the stability index in the chair back tilting process, Xn represents the comfort index when the chair back is at the nth tilting angle, and M represents the comfort index when the chair back is at the nth tilting angle; x represents the average value of the comfort indexes of the chair back at n tipping angles, and n represents the value number of the tipping angles of the chair back; the tipping performance of the chair back is represented through the comfort index X alpha and the stability index S. According to the invention, the tipping performance of the chair back can be effectively tested, and an effective basis is provided for the development of chairs.

Description

Technical Field

[0001] The present invention relates to the technical field of chair testing, and in particular to a chair back tilt performance testing method. Background Art

[0002] With the promotion and popularization of ergonomic concepts, a large number of ergonomic chairs have emerged on the market. Different ergonomic chairs have vastly different backrest tilt experiences. The optimal backrest tilt experience is primarily determined by ensuring that the force required from the abdomen, waist, and back during dynamic backward and forward leaning and rising is minimized and stable.

[0003] Currently, there is a lack of a method for effectively testing the reclining performance of a seat back. Summary of the Invention

[0004] The purpose of the present invention is to solve the problems existing in the above-mentioned prior art and to provide a chair back tilt performance testing method, which can effectively test the tilt performance of the chair back and provide an effective basis for the development of chairs.

[0005] The purpose of the present invention is achieved through the following technical solutions: A method for testing seat back reclining performance, comprising: During the chair back tilt process, obtain: the pressure exerted by the subject leaning naturally on the chair back, and the support force exerted by the chair back on the subject; The index used to characterize human comfort when the chair back is tilted is calculated: Xα=mα-Mα, where Xα represents the comfort index when the chair back is tilted at an angle of α, Mα represents the pressure exerted by the subject on the chair back when the chair back is tilted at an angle of α, and mα represents the support force exerted by the chair back on the subject when the chair back is tilted at an angle of α. The index used to characterize the stability of the chair back support for the subject during the reclining process is calculated: S represents the stability index of the seat back during reclining, Xn represents the comfort index of the seat back at the nth reclining angle, X represents the average value of the comfort index of the seat back at n reclining angles, and n represents the number of reclining angles of the seat back: The comfort index Xα and the stability index S are used to characterize the reclining performance of the seat back.

[0006] Preferably, the pressure exerted on the chair back by the subject who naturally leans on the chair back is obtained, including: Step 1002: Based on the subject's weight and the normal weight distribution of various parts of the human body, obtain the gravity of the part of the subject leaning on the chair back; Step 1004, based on the gravity of the part of the chair back that the subject leans on and the reclining angle of the chair back, obtain the pressure exerted by the subject on the chair back: Mα=M×sinα, Mα represents the pressure exerted by the subject on the chair back when the reclining angle of the chair back is α, M represents the gravity of the part of the chair back that the subject leans on, and α is the reclining angle of the chair back.

[0007] Preferably, the proportion of the weight of the part of the subject leaning on the chair back to the overall weight is 61.4%-65.4%.

[0008] Preferably, obtaining the support force exerted by the chair back on the subject includes: A vertical and backward pulling force is applied to the chair back. When the chair back reaches the set reclining angle, the pulling force at this time is used as the supporting force generated by the chair back on the subject at this reclining angle.

[0009] Preferably, a chair back tilt force value test device is used to obtain the support force generated by the chair back on the test subject. The chair back tilt force value test device includes a test bench, a seat fixing mechanism, a traction mechanism, a traction belt, a tension sensor, a chair back clamp and a human body simulation counterweight. The traction mechanism includes a traction motor, a swing arm provided at the output end of the traction motor, an adjustment seat connected to the swing arm for sliding up and down, and a lifting drive mechanism provided on the swing arm for driving the adjustment seat to move up and down. The seat fixing mechanism is provided on the test bench, the traction mechanism is provided on one side of the test bench, the traction belt is provided between the adjustment seat and the chair back clamp, and the tension sensor is provided at one end of the traction belt. Under a series of set chair back tilt angle conditions, obtain the support force exerted by the chair back on the subject, including: Step 1012: The chair to be tested is fixed to the test bench via the seat fixing mechanism, with the chair to be tested facing away from the traction mechanism, the chair back fixture is clamped on the chair back, and a human body simulation counterweight is placed on the chair to be tested; Step 1014: Through the actions of the traction mechanism and the lifting drive mechanism, the traction belt continuously applies a pulling force of 90°±a to the chair back. The pulling force value of the tension sensor is recorded when the chair back is tilted to each set angle, where 0°≤a≤10°. Step 1016: When the chair back is tilted to the maximum angle, the traction mechanism and the lifting drive mechanism are reset to return the chair back to the initial position; Step 1018, repeat steps 1014 and 1016 for a set number of times, and record the average value of the tension of the chair back at each set reclining angle as the supporting force generated by the chair back on the subject at the corresponding reclining angle.

[0010] Preferably, the chair back clamp is provided with a first inclination sensor, and the traction belt is provided with a second inclination sensor; in the step 1014, the inclination angle of the chair back is obtained based on the measurement value of the first inclination sensor; the inclination angle of the traction belt is obtained based on the measurement value of the second inclination sensor; the inclination angle of the traction belt is adjusted according to the inclination angle of the chair back, so that the angle at which the traction belt applies tension to the chair back is 90°±a.

[0011] Preferably, the traction belt is provided with a sensor mounting structure, which includes an angle piece and a clamping plate. The clamping plate and the angle piece are interconnected and clamped on the traction belt up and down. The second inclination sensor is provided on the side of the angle piece.

[0012] Preferably, the sensor mounting structure further includes an adjustment plate, which is arranged between the corner piece and the second inclination sensor.

[0013] Preferably, one end of the traction belt connected to the chair back clamp is provided with an angle observation piece, one end of the angle observation piece is provided with a reference groove, and observation ports are opened on the front and rear sides of the reference groove. One end of the traction belt extends from the middle of the upper and lower sides of the reference groove and is connected to the angle observation piece.

[0014] Preferably, the test bench includes a base, a platform slidably connected to the base, and a linear drive mechanism provided between the base and the platform. The platform moves in a direction approaching or away from the traction mechanism under the traction of the linear drive mechanism.

[0015] The advantages of the present invention are: 1. By designing the comfort index and the stability index, the human comfort during the chair back reclining process is intuitively represented, thereby achieving effective testing of the chair back reclining performance and providing an effective basis for chair development; 2. The weight of the part of the chair back that the test subject leans on is theoretically used to represent the vertical force acting on the chair back to represent the pressure exerted by the test subject on the chair back, which simplifies the test process and improves the test efficiency. 3. Using chair back tilt force test equipment to obtain the support force exerted on the test person during the chair back tilt process can effectively ensure the accuracy of the force direction, thereby ensuring the accuracy of the test results. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A flowchart of a seat back reclining performance testing method provided in an embodiment of this specification; Figure 2 This is a schematic diagram of the normal weight distribution of various parts of the human body in a sitting position; Figure 3 A schematic diagram of the structure of a chair back tilt force test device provided in an embodiment of this specification; Figure 4 for Figure 3 Schematic diagram of the enlarged structure at A in the middle; Figure 5 for Figure 3 Schematic diagram of the enlarged structure at B in the middle; Figure 6 A schematic diagram of the connection structure between the chair back clamp and the traction belt provided in the embodiment of this specification; Figure 7 for Figure 6 Schematic diagram of the enlarged structure at C in the middle; Figure 8 A schematic diagram of the structure of the angle observation member provided in the embodiment of this specification; Figure 9 A schematic diagram of the structure of the traction mechanism provided in the embodiment of this specification; Figure 10 This is a schematic diagram of the situation where the two curves mα and Mα have a high degree of overlap; Figure 11 This is a schematic diagram of the situation where the overlap between the mα and Mα curves is low; Figure 12 This is a schematic diagram of the situation where the Xα curve fluctuation is relatively stable; Figure 13 This is a schematic diagram of the situation where the curve of Xα fluctuates greatly; DETAILED DESCRIPTION

[0017] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0018] As a person leans back against a chair, the vertical weight of the upper body on the chair back changes as the tilt angle increases. Therefore, the upper body requires different support forces from the chair back as it tilts to different angles. If the support force exceeds the weight of the upper body on the chair back at that tilt angle, or even exceeds it by a significant amount, the subject will need to exert force to tilt back or will be unable to do so. If the support force is lower than the weight of the upper body on the chair back at that tilt angle, or even lower by a significant amount, the subject will need to exert force to tilt back or will feel suspended in mid-air.

[0019] Therefore, as mentioned in the background art, a better chair back tilt feeling is mainly reflected in the following: when the human body is dynamically leaning back and dynamically standing up, the force required by the human body's abdomen, waist and back is as small and stable as possible. This requires: on the one hand, when the human body naturally leans on the chair back, the pressure exerted on the chair back needs to be equivalent to the chair back's tendency to return to its initial state in the tilted state, and the supporting force exerted on the human body, so as to achieve the purpose of minimizing the force required on the human body's abdomen, waist and back. On the other hand, at different tilt angles of the chair back, the difference between the pressure exerted on the chair back by the human body and the supporting force exerted by the chair back on the human body needs to be relatively stable, so that the force required on the human body's abdomen, waist and back will be relatively stable throughout the entire tilting process.

[0020] For this reason, Figure 1 As shown, this embodiment provides a method for testing the seat back reclining performance, comprising the following steps: Step 100 , during the chair back tilting process, obtain: the pressure exerted on the chair back by the subject leaning naturally on the chair back, and the supporting force exerted on the subject by the chair back.

[0021] Specifically, the pressure and support force can be obtained by measuring every 2° starting from the initial state, such as 0°, 2°, 4°, ..., 90°. Of course, the tilt range of different chairs is different, and the angle condition can be set according to the actual tilt range of the chair to be tested.

[0022] Regarding obtaining the pressure exerted on the chair back by the subject leaning naturally on it, in order to simplify the testing process, improve testing efficiency, and avoid the influence of the human body's active force on the test results, as well as the influence of the complex structure of the human back on the pressure measurement, this embodiment uses the following method to obtain the theoretical value as the pressure exerted on the chair back by the subject: Step 1002: Based on the subject's weight and the normal weight distribution of various parts of the human body, the gravity of the part of the subject leaning on the chair back is obtained; wherein, the subject's weight can be selected according to the test requirements or the main target group of the chair to be tested. In this embodiment, taking 68kg as an example, the gravity of the subject is 68×9.8=666.4N. Figure 2The typical weight distribution of various parts of the human body in the seated position shown is based on the 41st Chinese edition of Gray's Anatomy: Anatomical Foundations of Clinical Practice—Head and Neck: Chapter 7 (Head and Neck Anatomy), Trunk: Chapter 5 (Chest Wall), Chapter 9 (Abdomen), Chapter 11 (Pelvis), Extremities: Chapter 6 (Upper Extremities), Chapter 8 (Lower Extremities), and the NASA Anthropometric Data Handbook. The body parts of the subject that rest on the chair back primarily include the head, neck, shoulders, upper arms, chest, back, and spine. The weight of these parts accounts for 8% + 5.4% + 50% = 63.4%. Therefore, the weight of the 68kg subject resting on the chair back is 666.4 × 63.4% = 422.5N.

[0023] In step 1004, the pressure exerted by the subject on the chair back is calculated based on the weight of the portion of the chair backrest where the subject is leaning and the chair backrest angle: Mα = M × sinα, where Mα represents the pressure exerted by the subject on the chair backrest when the chair backrest angle is α, M represents the weight of the portion of the chair backrest where the subject is leaning, and α represents the chair backrest angle. Using the aforementioned angle conditions of 0°, 2°, 4°, ..., and 90° as an example, the data in Table 1 are calculated.

[0024] Table 1 Data of the pressure exerted on the chair back by a 68kg test subject at an angle of α Tilt angle (°) 0 2 4 6 ……… 88 90 Mα(N) 0 14.7 29.5 44.2 ……… 422.2 422.5 To determine the support force exerted by the chair back on the test subject, a vertical and backward pulling force is applied to the chair back. When the chair back reaches the set recline angle, the pulling force at that point is used as the support force exerted by the chair back on the test subject at that recline angle. It should be noted that due to various errors, the direction of the pulling force applied to the chair back is theoretically vertical, not absolutely vertical. Slight deviations in the angle will not significantly affect the test results. For example, the acceptable angle is 90°±10°. The same principle applies below and will not be further explained.

[0025] This embodiment specifically uses a chair back tilt force value testing device to obtain the above-mentioned support force, such as Figure 3 、 4As shown in Figures 9 and 10, the test equipment includes a test bench 1, a seat fixing mechanism 2, a traction mechanism 3, a traction belt 4, a seat back clamp 5, a tension sensor 6, and a human body simulation counterweight 7. The seat fixing mechanism 2 is mounted on the test bench 1 and secures the lower portion of the chair to prevent movement without affecting the normal tilt of the seat back. The human body simulation counterweight 7 is placed on the seat to simulate the pressure exerted by people of different weights on the seat, ensuring test accuracy. The seat back clamp 5 is clamped to the seat back to provide a stable connection. The tension sensor 6 is mounted vertically on the side of the seat back clamp 5 to ensure that the direction of tension is perpendicular to the seat back. The traction mechanism 3 is mounted on one side of the test bench 1 and includes a traction motor 31, a swing arm 32 located at the output end of the traction motor 31, an adjustment seat 33 that slides vertically connected to the swing arm 32, and a lifting drive mechanism on the swing arm 32 that drives the adjustment seat 33 up and down. The traction belt 4 is connected to the adjustment seat 33 at one end and to the tension sensor 6 at the other end. The traction mechanism 3 pulls the traction belt 4, thereby pulling the chair back, by swinging the swing arm 32. The adjustment seat 33 is used to adjust the tilt angle of the traction belt 4 to ensure that the pulling force is perpendicular to the chair back. The backrest clamp 5 is equipped with a first tilt sensor 81 for detecting the backrest tilt angle. The traction belt 4 is equipped with a second tilt sensor 82 for detecting the traction belt tilt angle and, based on the backrest tilt angle, adjusting the angle between the traction belt 4 and the chair back.

[0026] Specifically, in order to improve the convenience of use, the first inclination sensor 81 and the second inclination sensor 82 can be preset to the same initial state, such as Figure 4 As shown, for example, the initial state of the chair back is vertical, and the pulling direction of the traction belt 4 needs to be perpendicular to the chair back, then the initial state of the traction belt 4 is horizontal, and the first inclination sensor 81 and the second inclination sensor 82 are respectively arranged on the sides of the chair back clamp 5 and the traction belt 4. It can be seen that at this time, the states of the two inclination sensors are consistent and the measured values are the same; when the chair back is tilting, in order to make the pulling direction of the traction belt 4 perpendicular to the chair back, the measured values of the two inclination sensors need to be consistent, that is, when adjusting the angle of the traction belt 4, it is only necessary to make the measured value of the second inclination sensor 82 the same as the measured value of the first inclination sensor 81.

[0027] like Figure 6 and 7As shown, in order to mount the second inclination sensor 82 on the side of the traction belt 4, a sensor mounting structure is provided on the traction belt 4. The sensor mounting structure includes an angle piece and a clamping plate 101. The angle piece includes a horizontal plate 102 and a vertical plate 103. The clamping plate 101 and the horizontal plate 102 are connected to each other by bolts and clamped to the upper and lower sides of the traction belt 4. The second inclination sensor 82 can be mounted on the vertical plate 103, thereby maintaining the same state as the first inclination sensor 81. To compensate for errors, an adjustment plate 104 is provided between the vertical plate 103 and the second inclination sensor 82. The adjustment plate 104 has two connecting holes, one of which is an arc-shaped hole 1041 centered on the other connecting hole. The vertical plate 103 has two conventional connecting holes. In this way, the arc-shaped holes 1041 can be used to fine-tune the mounting angle of the adjustment plate 104 and the second inclination sensor 82, and then tightened with bolts and nuts to ensure the accuracy of the initial state of the second inclination sensor 82.

[0028] like Figure 8 As shown, to facilitate the tester's timely detection of any anomalies in the traction belt 4's angle, an angle observation device is provided between the tension sensor 6 and the traction belt 4. The angle observation device comprises a connecting base 111 and reference plates 112 disposed on opposite sides of the connecting base 111. The connecting base 111 is bolted to the tension sensor 6. The two reference plates 112 extend toward the traction belt 4, forming a reference groove 113 therebetween. The front and rear sides of the reference groove 113 are continuous, serving as an observation port. One end of the traction belt 4 extends between the two reference plates 112 and connects to a connecting shaft disposed in the middle of the connecting base 111. As the tension sensor 6 is perpendicularly connected to the seat back fixture 5, when the traction belt 4 is also perpendicular to the seat back fixture 5, it is aligned with the tension sensor 6. At this point, the traction belt 4 is positioned midway between the two reference plates 112. If the traction belt 4 approaches or contacts one of the reference plates, it indicates an anomaly in the traction belt's angle and requires adjustment. Alternatively, the range between the two reference plates 112 is used as the acceptable traction belt angle deviation range. As long as the traction belt 4 does not contact any reference plate, the deviation is considered to be within the acceptable range and the test proceeds normally. Once the traction belt 4 contacts one of the reference plates, adjustment is required.

[0029] The following is an introduction to the other parts of the test equipment structure, such as Figure 5 As shown, the structure of the seat fixing mechanism 2 is relatively conventional, mainly comprising a pressing ring 21, a plurality of fixing screws 22 vertically arranged on the test bench 1, and a fixing hand wheel 23 threadedly connected to the fixing screws 22. The pressing ring 21 is provided with a notch that matches the pneumatic rod of the chair. When in use, the pressing ring 21 is pressed on the five claws of the chair, and then the fixing hand wheel 23 is used to press the pressing ring 21 downward to achieve the pressing and fixing of the five claws by the pressing ring. Figure 6As shown, the structure of the chair back clamp 5 is also relatively conventional, mainly including two clamping rods 51, two clamping screws 52 connecting the two clamping rods 51, and clamping nuts and clamping handwheels 53 provided at both ends of the clamping screws 52. When in use, the two clamping rods 51 are clamped on the front and back sides of the chair back respectively, and then the distance between the two clamping rods 51 is shortened by using the clamping nuts and clamping handwheels 53 until the chair back is clamped.

[0030] like Figure 9 As shown, the lifting drive mechanism includes a lifting motor 341, a lifting screw 342 located at the output end of the lifting motor 341, and a lifting nut 343 located on the adjustment seat 33. The lifting screw 342 is threadedly connected to the lifting nut 343 and extends along the length of the swing arm 32. The rotation of the lifting screw drives the lifting nut and the adjustment seat up and down, ensuring stable and reliable lifting and adjustment. The swing arm 32 includes two spaced-apart columns 321. The lifting motor 341 is located at the upper ends of the two columns 321, and the lifting screw 342 is located between the two columns 321 to prevent interference between the lifting screw and external factors and facilitate the installation of the lifting motor. To ensure the safety of the equipment, limit trigger plates 344 are installed on the upper and lower sides of the adjustment seat 33, and micro switches 345 are installed on the upper and lower parts of the swing arm 32 to cooperate with the limit trigger plates 344 to prevent the adjustment seat from moving beyond the safe range.

[0031] like Figure 3 As shown, since the traction belt has a fixed length, to improve the device's applicability to chairs of varying sizes, the test bench 1 comprises a base 11, a platform 12 slidably connected to the base 11, and a linear drive mechanism positioned between the base 11 and the platform 12. The platform moves toward or away from the traction mechanism. The linear drive mechanism comprises a linear motor, a linear screw 13 connected to the output end of the linear motor, and a linear nut positioned at the bottom of the platform. This allows the distance between the chair and the traction mechanism to be adjusted to meet the testing requirements of chairs of varying sizes.

[0032] Based on the above-mentioned testing equipment, this embodiment obtains the support force exerted by the chair back on the test subject, including the following steps: Before testing: Assemble and assemble the chair to be tested, then adjust it to its normal operating position to ensure proper backrest reclining. Determine the backrest reclining range based on the manufacturer's data. If this is unavailable, test within the actual range of motion. The initial backrest angle should be measured according to EN1335-1:2020+A1:2022. Measure the test environment temperature to ensure it meets the test requirements. For example, the ambient temperature should be between 15°C and 27°C. Any deviations from this range should be recorded.

[0033] During testing: Step 1012: fix the chair to be tested on the test bench through the seat fixing mechanism, with the back of the chair to be tested facing the traction mechanism, clamp the chair back clamp on the chair back, and place the human body simulation counterweight on the chair to be tested; among them, the tension sensor 6 and the traction belt 4 on the chair back clamp 5 need to be aligned with the vertical center line of the chair back, and the human body simulation counterweight needs to be placed at the center of the seat. In this embodiment, the weight of the human body simulation counterweight selected is 68 kg.

[0034] In step 1014, the traction mechanism and the lifting drive mechanism are operated to make the traction belt continuously apply a pulling force of 90°±10° to the chair back, and the pulling force value of the pulling force sensor is recorded when the chair back is tilted to each set angle. Among them, the tilt angle of the chair back is obtained by the first tilt sensor, and the angle between the traction belt 4 and the chair back is adjusted according to the measurement values of the second tilt sensor and the first tilt sensor. For example, in the process of the chair back tilting backward, when the measurement value of the first tilt sensor reaches 30°, the measurement value of the second tilt sensor may be 20°. At this time, it is necessary to move the adjustment seat 33 downward to make the tilt angle of the traction belt 4 close to 30° to maintain the angle between the traction belt 4 and the chair back at about 90°. Of course, in the process of the adjustment seat 33 moving downward, in order to maintain the tilt angle of the chair back, the traction mechanism also needs to pull the traction belt backward appropriately. Therefore, the adjustment action is relatively complicated. In order to simplify the operation and improve the test efficiency, the angle range between the traction belt 4 and the chair back received by the above test class is set, that is, 90°±10°, to avoid frequent angle adjustment of the traction belt.

[0035] When the backrest is in its initial position, no tension can be applied to it to ensure the accuracy of its initial position. The default tilt angle of the backrest in its initial position is 0°. The first tilt sensor and the second tilt sensor can be zeroed at the initial position. After that, the tension value of the tension sensor is recorded every time the backrest tilt angle changes by 2°. In order to ensure test efficiency, the above test process is carried out continuously, that is, the backrest tilt angle continues to change, and when the corresponding tilt angle is reached, the tension value at the corresponding moment is recorded. Therefore, in order to ensure the accuracy of the data, it is necessary to control the rate at which the backrest tilts to prevent excessive loading from affecting the test results. In step 1016, when the chair back has tilted to its maximum angle, the traction mechanism and the lift drive mechanism are reset to return the chair back to its initial position. The maximum angle can be set based on the test requirements of the chair under test, provided that it does not exceed the normal tilt range of the chair under test. When the chair back returns to its initial position, no tension is applied to ensure that it fully returns to its initial position.

[0036] Step 1018: Repeat steps 104 and 106 a set number of times, recording the average of the tension at each set recline angle as the support force exerted by the chair back on the subject at that recline angle. The set number of times can be five, and the average of these multiple measurements can be used to reduce measurement errors.

[0037] Step 200, calculate and obtain the index used to characterize the comfort of the human body when the chair back is tilted: Xα=mα-Mα, Xα represents the comfort index when the chair back tilt angle is α, Mα represents the pressure exerted by the subject on the chair back when the chair back tilt angle is α, and mα represents the supporting force exerted by the chair back on the subject when the chair back tilt angle is α. At any tilt angle, the closer the value of Xα is to 0, the higher the comfort of the subject. The subject can rely on the weight of the upper body to complete the entire tilting action without the need for additional muscle force, and there will be no instantaneous feeling of suspension. Since we tested the entire process of chair back tilting, namely the above-mentioned 0°, 2°, 4°, ..., 90°, in order to facilitate the observation of the overall test results, the curve of Mα changing with α and the curve of mα changing with α can be compared together. The higher the degree of overlap of the two curves, the higher the comfort of the subject during the entire tilting process. As Figure 10 The two curves have a high overlap, indicating a high reclining comfort. Figure 11 The two curves show a low overlap, indicating poor reclining comfort. Of course, the above results only represent test results for a specific weight participant. For example, this example uses data from a 68kg participant. However, since the pressure exerted on the chair back by the participant at any reclining angle is a calculated theoretical value, we can quickly obtain test results for participants of other weights as needed.

[0038] In step 300, we can also draw a curve showing the change of Xα with α. The more horizontal the curve is, the smaller the fluctuation of Xα is during the entire reclining process, and the more stable the chair back supports the subject. In other words, the subject's experience during the entire reclining process is relatively unstable, and there is no occasional need for excessive force or retraction. Figure 12 The following shows a situation where the seat back support is more stable, such as Figure 13 The illustration shows a situation where the seat back support is less stable.

[0039] In order to make the representation of the chair back support stability simpler and more intuitive, we can use the variance formula to calculate the index used to characterize the stability of the chair back support for the subject during the reclining process: S represents the stability index during seatback reclining, Xn represents the comfort index at the nth reclining angle, X represents the average comfort index at n reclining angles, and n represents the number of reclining angles. Therefore, a smaller S value indicates a more stable seatback support, while a larger S value indicates a less stable seatback support.

[0040] Step 400 : Characterizing the reclining performance of the chair back through the comfort index Xα and the stability index S, thereby providing an effective basis for the development of the chair.

[0041] The above is merely a preferred embodiment of the present invention, which is one implementation method based on the overall concept of the present invention. The scope of protection of the present invention is not limited to this embodiment. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A chair back tilt performance testing method, characterized in that: include: During the chair back tilt process, obtain: the pressure exerted by the subject leaning naturally on the chair back, and the support force exerted by the chair back on the subject; The index used to characterize human comfort when the chair back is tilted is calculated: Xα=mα-Mα, where Xα represents the comfort index when the chair back is tilted at an angle of α, Mα represents the pressure exerted by the subject on the chair back when the chair back is tilted at an angle of α, and mα represents the support force exerted by the chair back on the subject when the chair back is tilted at an angle of α. The index used to characterize the stability of the chair back support for the subject during the reclining process is calculated: S represents the stability index during the reclining process of the chair back, X n It represents the comfort index of the seat back at the nth reclining angle, X represents the average comfort index of the seat back at n reclining angles, and n represents the number of reclining angles: The comfort index Xα and the stability index S are used to characterize the reclining performance of the seat back.

2. A chair back tilt performance testing method according to claim 1, characterized in that: Obtain the pressure exerted on the chair back by the subject leaning naturally on the chair back, including: Step 1002: Based on the subject's weight and the normal weight distribution of various parts of the human body, obtain the gravity of the part of the subject leaning on the chair back; Step 1004, based on the gravity of the part of the chair back that the subject leans on and the reclining angle of the chair back, obtain the pressure exerted by the subject on the chair back: Mα=M×sinα, Mα represents the pressure exerted by the subject on the chair back when the reclining angle of the chair back is α, M represents the gravity of the part of the chair back that the subject leans on, and α is the reclining angle of the chair back.

3. A chair back tilt performance testing method according to claim 2, characterized in that: The proportion of the weight of the part of the subject leaning on the chair back to the overall weight is 61.4%-65.4%.

4. A chair back tilt performance testing method according to claim 1, characterized in that: Obtain the support force exerted by the chair back on the subject, including: A vertical and backward pulling force is applied to the chair back. When the chair back reaches the set reclining angle, the pulling force at this time is used as the supporting force generated by the chair back on the subject at this reclining angle.

5. The chair back tilt performance testing method according to claim 1, characterized in that: A chair back tilt force test device is used to obtain the support force exerted by the chair back on the test subject. The chair back tilt force test device includes a test bench, a seat fixing mechanism, a traction mechanism, a traction belt, a tension sensor, a chair back fixture, and a human body simulation counterweight. The traction mechanism includes a traction motor, a swing arm provided at the output end of the traction motor, an adjustment seat connected to the swing arm for vertical sliding movement, and a lifting drive mechanism provided on the swing arm for driving the adjustment seat to move up and down. The seat fixing mechanism is set on the test bench, the traction mechanism is set on one side of the test bench, the traction belt is set between the adjustment seat and the seat back clamp, and the tension sensor is set at one end of the traction belt; Under a series of set chair back tilt angle conditions, obtain the support force exerted by the chair back on the subject, including: Step 1012: The chair to be tested is fixed to the test bench via the seat fixing mechanism, with the chair to be tested facing away from the traction mechanism, the chair back fixture is clamped on the chair back, and a human body simulation counterweight is placed on the chair to be tested; Step 1014: Through the actions of the traction mechanism and the lifting drive mechanism, the traction belt continuously applies a pulling force of 90°±a to the chair back. The pulling force value of the tension sensor is recorded when the chair back is tilted to each set angle, where 0°≤a≤10°. Step 1016: When the chair back is tilted to the maximum angle, the traction mechanism and the lifting drive mechanism are reset to return the chair back to the initial position; Step 1018, repeat steps 1014 and 1016 for a set number of times, and record the average value of the tension of the chair back at each set reclining angle as the supporting force generated by the chair back on the subject at the corresponding reclining angle.

6. A chair back tilt performance testing method according to claim 5, characterized in that: The chair back clamp is provided with a first inclination sensor, and the traction belt is provided with a second inclination sensor; in the step 1014, the inclination angle of the chair back is obtained based on the measurement value of the first inclination sensor; the inclination angle of the traction belt is obtained based on the measurement value of the second inclination sensor; the inclination angle of the traction belt is adjusted according to the inclination angle of the chair back, so that the angle at which the traction belt applies tension to the chair back is 90°±a.

7. A chair back tilt performance testing method according to claim 6, characterized in that: The traction belt is provided with a sensor mounting structure, which includes an angle piece and a clamping plate. The clamping plate and the angle piece are connected to each other and clamped on the traction belt up and down. The second inclination sensor is provided on the side of the angle piece.

8. A chair back tilt performance testing method according to claim 7, characterized in that: The sensor installation structure further includes an adjustment plate, which is arranged between the corner piece and the second inclination sensor.

9. The chair back tilt performance testing method according to claim 5, characterized in that: One end of the traction belt connected to the chair back clamp is provided with an angle observation piece, and one end of the angle observation piece is provided with a reference groove. Observation ports are opened on the front and rear sides of the reference groove. One end of the traction belt extends into the middle of the upper and lower sides of the reference groove and is connected to the angle observation piece.

10. The chair back tilt performance testing method according to claim 5, characterized in that: The test bench includes a base, a platform slidably connected to the base, and a linear drive mechanism disposed between the base and the platform. The platform moves in a direction approaching or away from the traction mechanism under the traction of the linear drive mechanism.

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