Stepless adjustment mechanism and chair back

Abstract

The utility model discloses a kind of stepless adjusting mechanism and chair back, the stepless adjusting mechanism includes fixed part, track is equipped on it, track includes main adjusting section and the unlocking section at the stroke end of main adjusting section, first deviation structure is equipped at unlocking section;Sliding member, can slide between main adjusting section and unlocking section along track;Locking assembly, be in sliding member, locking assembly includes eccentric wheel and torsion spring for the pre-tightening force of being applied to eccentric wheel with sliding member hinged connection.The utility model is formed by wedge-shaped self-locking mechanism of the cooperation of eccentric wheel and torsion spring, and the design of sectional track and first deviation structure, reliably lock in any position in main adjusting section is realized, the problem of low traditional step adjusting precision, comfort is insufficient is solved;Meanwhile, unlocking action is completed in stroke end unlocking section, only need to make eccentric wheel deviate track side wall to a certain degree, avoid the structure complex and heavy caused by long stroke operation, improve the adjustment efficiency and space utilization.

Description

Technical Field

[0001] This utility model relates to the field of seat technology, and in particular to a stepless adjustment mechanism and a chair back. Background Technology

[0002] Existing seat backrest adjustment mechanisms typically employ stepped adjustment methods, such as using preset fixed points or gear structures to adjust height. While simple, this design has significant limitations: limited adjustment precision, users cannot lock the seat at any arbitrary position, and are limited to a few predetermined positions, resulting in insufficient comfort. Furthermore, traditional mechanisms often require a long sliding travel to complete the unlocking and locking actions, which not only makes the structure complex and bulky but also limits the overall compactness and space utilization of the seat design. In addition, traditional mechanisms are susceptible to interference from external forces (such as gravity or user leaning) during adjustment, leading to unstable locking.

[0003] To address the aforementioned issues, a stepless adjustment mechanism is needed that can achieve stepless locking at any position, efficient operation, and improved reliability, thereby enhancing the user experience and the overall seat design. Utility Model Content

[0004] The main purpose of this utility model is to provide a stepless adjustment mechanism and a chair back to solve the above-mentioned technical problems.

[0005] Firstly, this utility model provides a stepless adjustment mechanism, comprising:

[0006] A fixing component is provided with a track, the track including a main adjustment section and an unlocking section located at the end of the stroke of the main adjustment section, and the unlocking section is provided with a first offset structure;

[0007] The slider can slide along the track between the main adjustment section and the unlocking section;

[0008] A locking assembly is disposed within the slider, the locking assembly including an eccentric wheel pivotally connected to the slider and a torsion spring for applying a preload to the eccentric wheel;

[0009] When the slider is located in the main adjustment section and the eccentric wheel is in the locking preparation state, the torsion spring drives the eccentric wheel to abut against the side wall of the track, and when the slider is subjected to a force in a preset locking direction, the eccentric wheel and the side wall of the track form a wedge-shaped self-locking mechanism.

[0010] When the slider slides to the unlocking section, the first offset structure guides the eccentric wheel to disengage from the track sidewall, so that the eccentric wheel is in the unlocked state;

[0011] When the slider returns from the unlocking section to the main adjustment section, the torsion spring drives the eccentric wheel to remain disengaged from the track sidewall until the eccentric wheel returns to the locking ready state.

[0012] The eccentric wheel includes an eccentric wheel body and a first abutting portion and a second abutting portion disposed on the eccentric wheel body; the torsion spring is configured to abut against the first abutting portion or the second abutting portion to apply a corresponding preload.

[0013] When the torsion spring drives the eccentric wheel to abut against the side wall of the track, the torsion spring applies a preload to the first abutment portion; when the torsion spring drives the eccentric wheel to remain detached from the side wall of the track, the torsion spring applies a preload to the second abutment portion.

[0014] The fixing member is also provided with a guide groove; the eccentric wheel also includes a positioning part provided on the eccentric wheel body, the positioning part passing through the guide groove; the first offset structure includes an inclined surface, the inclined surface of the first offset structure is formed on one side wall of the guide groove; when the sliding member slides to the unlocking section, the positioning part abuts against the inclined surface of the first offset structure and overcomes a preset resistance, so that the eccentric wheel rotates around its pivot to disengage from the side wall of the track.

[0015] The track also includes a reset section located at the beginning of the main adjustment section stroke. The reset section is provided with a second offset structure, which includes another inclined surface. The inclined surface of the second offset structure is formed on the other side wall of the guide groove. When the slider returns from the unlocking section to the reset section, the positioning part abuts against the inclined surface of the second offset structure and overcomes another preset resistance to guide the eccentric wheel back to the locking preparation state.

[0016] The torsion spring includes a torsion spring body fixedly connected to the sliding member and a hook disposed on the torsion spring body; a loop path is formed between the first abutment portion and the second abutment portion, and the hook is configured to move along the loop path to abut against the first abutment portion or the second abutment portion; wherein the starting point and the ending point of the loop path are the same position of the first abutment portion.

[0017] The device includes an outer tube and an inner tube, with the inner tube slidably disposed within the outer tube; the fixing member is fixedly disposed on the inner wall of the outer tube; the outer wall of the inner tube is provided with a receiving groove along its length, and the sliding member is fixedly disposed within the receiving groove and located between the fixing member and the inner tube.

[0018] The fastener has an L-shaped structure and includes a mounting part and a guide rail part that is perpendicular to the mounting part; the rail is formed on the guide rail part and the guide groove is provided on the mounting part.

[0019] The outer wall of the inner tube is provided with a limiting groove, and a limiting part extends from the guide rail. The limiting part is slidably disposed in the limiting groove to limit the sliding stroke of the inner tube.

[0020] The sliding member is a box with an inner cavity. The box has an opening on the side near the guide rail. The eccentric wheel abuts against the side wall of the rail through the opening. The box has a guide groove on the side near the mounting part. The positioning part passes through the guide groove.

[0021] Secondly, this utility model also provides a chair back, including a backrest support and an adjustable component, wherein a stepless adjustment mechanism as described in the first aspect is provided between the backrest support and the adjustable component; wherein the adjustable component is a lumbar support or a backrest body.

[0022] The beneficial technical effects of this utility model are as follows:

[0023] This invention utilizes a wedge-shaped self-locking mechanism formed by the cooperation of an eccentric wheel and a torsion spring, along with a segmented track and a first offset structure, to achieve reliable locking at any position within the main adjustment section. This solves the problems of low precision and insufficient comfort in traditional stepped adjustment. Simultaneously, the unlocking action is concentrated in the unlocking section at the end of the stroke, requiring only the eccentric wheel to deviate slightly from the track sidewall. This avoids the structural complexity and bulkiness caused by long-stroke operations, improving adjustment efficiency and space utilization. Furthermore, during the return process, the torsion spring drives the eccentric wheel to remain disengaged, preventing accidental locking and ensuring locking stability and a smooth and reliable overall adjustment process, significantly improving user experience and the durability of the mechanism. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 A schematic diagram of the internal structure of the stepless adjustment mechanism provided in this embodiment of the utility model;

[0026] Figure 2 for Figure 1 Enlarged diagram of A in the middle;

[0027] Figure 3A three-dimensional schematic diagram of the eccentric wheel in the continuously variable adjustment mechanism provided in this embodiment of the utility model;

[0028] Figure 4 A schematic diagram of the fit between the fixed component and the sliding component in the stepless adjustment mechanism provided in this embodiment of the utility model;

[0029] Figure 5 A three-dimensional schematic diagram of the fixing component in the stepless adjustment mechanism provided in this embodiment of the utility model;

[0030] Figure 6 A three-dimensional schematic diagram of the sliding component of the stepless adjustment mechanism provided in this embodiment of the utility model;

[0031] Figure 7 A schematic diagram of the fit between the outer tube and the inner tube in the stepless adjustment mechanism provided in this embodiment of the utility model;

[0032] Figure 8 A schematic diagram of the inner tube and its sliding component in the stepless adjustment mechanism provided in this embodiment of the utility model;

[0033] Figure 9 A schematic diagram of the backrest support and lumbar support provided in the embodiment of this utility model.

[0034] Explanation of reference numerals in the attached figures:

[0035] In the diagram: 10-Stepless adjustment mechanism, 20-Fixing component, 21-Railway, 22-First offset structure, 23-Second offset structure, 24-Guide groove, 25-Mounting part, 26-Guide rail part, 261-Limiting part, 30-Sliding component, 32-Opening, 33-Guide groove, 50-Eccentric wheel, 51-Eccentric wheel body, 52-First abutting part, 53-Second abutting part, 54-Positioning part, 60-Torsion spring, 61-Torsion spring body, 62-Hook, 70-Outer tube, 80-Inner tube, 81-Accommodation groove, 82-Limiting groove, 91-Backrest bracket, 92-Lumbar support, 100-Circulation path, 101-Slope block. Detailed Implementation

[0036] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0037] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0038] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0039] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0040] Please also refer to Figures 1-6 This utility model embodiment provides a stepless adjustment mechanism that can be applied to various scenarios requiring stepless positioning, such as adjusting the fore-and-aft position of a seat lumbar support 92 or the height adjustment of a seat back. The mechanism includes a fixing member 20 with a track 21, the track 21 comprising a main adjustment section and an unlocking section located at the end of the main adjustment section's stroke, the unlocking section having a first offset structure 22; a sliding member 30, slidable along the track 21 between the main adjustment section and the unlocking section; and a locking assembly disposed within the sliding member 30, the locking assembly including an eccentric wheel 50 pivotally connected to the sliding member 30 and a torsion spring 60 for applying a preload to the eccentric wheel 50; wherein, when the sliding member 30 is located in the main adjustment section and the eccentric wheel 50 is in a locking preparation state, the torsion spring 60... The eccentric wheel 50 is driven to abut against the side wall of the track 21, and when the slider 30 is subjected to a force in a preset locking direction, the eccentric wheel 50 and the side wall of the track 21 form a wedge-shaped self-lock; when the slider 30 slides to the unlocking section, the first offset structure 22 guides the eccentric wheel 50 to disengage from the side wall of the track 21, so that the eccentric wheel 50 is in the unlocked state; when the slider 30 returns from the unlocking section to the main adjustment section, the torsion spring 60 drives the eccentric wheel 50 to remain disengaged from the side wall of the track 21 until the eccentric wheel 50 returns to the locking preparation state.

[0041] In this embodiment, the stepless adjustment mechanism 10 includes a fixing member 20, a sliding member 30, and a locking component disposed within the sliding member 30.

[0042] Specifically, the fixing member 20 can be a component fixedly mounted on the seat back support 91, and the fixing member 20 itself is in a fixed state when the stepless adjustment mechanism 10 is in use. The fixing member 20 has a track 21, along which the sliding member 30 can reciprocate. The length direction of the track 21 is the same as the length direction of the fixing member 20, and the track 21 is divided into different functional sections (not separately labeled in the attached figure) along its length direction, including a main adjustment section and an unlocking section located at the end of the stroke of the main adjustment section. The main adjustment section is the main working area for locking the mechanism at any position. The unlocking section is used to release the locked state of the mechanism; here, the end of the stroke can be understood as one of the extreme positions of the sliding member 30's movement. To achieve the unlocking function, a first offset structure 22 is specifically provided at the unlocking section. This first offset structure 22 can mechanically interfere with the eccentric wheel 50 in the locking assembly, thereby changing the state of the locking assembly.

[0043] The slider 30 is a component that can slide along the aforementioned fixing member 20 and its upper track 21. It can be fixedly connected to the seat lumbar support 92 or the backrest body. For example, the user can adjust the lumbar support 92 forward and backward. At this time, the slider 30 slides steplessly relative to the fixing member 20 and its upper track 21. The slider 30 carries the locking component and slides between the main adjustment section and the unlocking section under the guidance of the fixing member 20 and its upper track 21.

[0044] The locking assembly, the core component for achieving stepless locking, is integrally housed within the slider 30. This locking assembly includes an eccentric wheel 50 and a torsion spring 60. The eccentric wheel 50 is pivotally connected to the slider 30 via a pivot, allowing it to rotate about this pivot. The eccentric wheel 50 has a non-circular profile, which is crucial for achieving wedge-shaped self-locking. One end of the torsion spring 60 is fixed to the slider 30, while the other end abuts against the eccentric wheel 50, applying a continuous preload to the eccentric wheel 50, giving it an initial tendency to lock or unlock.

[0045] When the slider 30 is in the main adjustment section of the track 21, the mechanism is in an adjustable or lockable working range. In the absence of external force, the eccentric wheel 50 is in a locked-ready state. At this time, the torsion spring 60 applies a preset torsional force (i.e., preload) to the eccentric wheel 50, which drives the eccentric outer edge of the eccentric wheel 50 to maintain slight contact with the side wall of the track 21. When the slider 30 is subjected to a force in a preset locking direction, for example, in the backrest body adjustment application, the downward force generated by the gravity of the backrest body is transmitted through the slider 30 and attempts to drive the eccentric wheel 50 to rotate about its pivot. Because the geometry of the eccentric wheel 50 is non-circular, its slight rotation causes the distance between its outer edge and the side wall of the track 21 to decrease rapidly, thereby generating a large positive pressure and friction, forming a stable wedge-shaped self-locking mechanism. This self-locking effect can firmly lock the slider 30 in its current position within the track 21, preventing it from sliding along the preset locking direction, thus achieving stepless locking at any position.

[0046] When the user needs to adjust the position, they can move the slider 30 in the opposite direction to the preset locking direction, for example, by lifting the backrest body upwards. At this time, the force direction is opposite to the preset locking direction. After overcoming the preload of the torsion spring 60, the eccentric wheel 50 rotates in the opposite direction, releasing the wedge-shaped contact with the side wall of the track 21. The slider 30 can then slide freely upwards within the track 21, stopping at any position during the sliding process. After stopping, the backrest body can self-lock at the current position using its own weight, thus achieving stepless locking of the backrest body at any position. When the user continues to move the slider 30 to the end of its stroke, i.e., entering the unlocked section of the track 21, the eccentric wheel 50 will interact with the first offset structure 22 of that section. The first offset structure 22 will force the eccentric wheel 50 to rotate around its pivot by a large angle, completely disengaging it from the contact with the side wall of the track 21. At this time, the eccentric wheel 50 is in the unlocked state. In this state, even if there is a force in the preset locking direction, the eccentric wheel 50 cannot form a wedge-shaped self-lock with the side wall of the track 21.

[0047] When the slider 30 is in the unlocked position and the eccentric wheel 50 is in the unlocked state, the user can return the slider 30 from the unlocked position to the main adjustment position. A key aspect of this return process is that the torsion spring 60 operates in a new manner, driving the eccentric wheel 50 to remain disengaged from the sidewall of the track 21. This means that the mechanism will not accidentally trigger the lock during the entire sliding process of the slider 30 from the unlocked position to the main adjustment position. This design ensures that the user can smoothly reset the slider 30 from another extreme position. Only when the slider 30 returns to a specific position (e.g., the beginning of the stroke) does the interaction between the torsion spring 60 and the eccentric wheel 50 change. The torsion spring 60 reapplies preload in its initial manner, driving the eccentric wheel 50 back to the locked, ready-to-lock state abutting against the sidewall of the track 21, thus completing a full cycle of "adjustment-unlocking-reset-readjustment".

[0048] The stepless adjustment mechanism 10 in this embodiment achieves reliable self-locking at any position within the main adjustment section through the cooperation of the eccentric wheel 50, the torsion spring 60 and the segmented track 21, and unlocks at the end of the stroke through the first offset structure 22. At the same time, during the return process from unlocking, the different working states of the torsion spring 60 are used to prevent accidental locking. The entire adjustment process is smooth, reliable and has high stroke efficiency.

[0049] In one embodiment, the eccentric wheel 50 includes an eccentric wheel body 51 and a first abutting portion 52 and a second abutting portion 53 disposed on the eccentric wheel body 51; the torsion spring 60 is configured to abut against the first abutting portion 52 or the second abutting portion 53 to apply a corresponding preload; wherein, when the torsion spring 60 drives the eccentric wheel 50 to abut against the side wall of the track 21, the torsion spring 60 applies a preload to the first abutting portion 52; when the torsion spring 60 drives the eccentric wheel 50 to remain disengaged from the side wall of the track 21, the torsion spring 60 applies a preload to the second abutting portion 53.

[0050] In this embodiment, the eccentric wheel 50 includes an eccentric wheel body 51 and a first abutment portion 52 and a second abutment portion 53 disposed on the eccentric wheel body 51. The eccentric wheel body 51 is the main body of the eccentric wheel 50, and its outer edge contour is used to achieve wedge-shaped self-locking with the side wall of the track 21. The first abutment portion 52 and the second abutment portion 53 are specific structures on the eccentric wheel body 51 that interact with the torsion spring 60, providing two different points of application for applying preload to the torsion spring 60.

[0051] Accordingly, the torsion spring 60 is configured to selectively abut against the first abutment portion 52 or the second abutment portion 53, thereby applying different preload forces to the eccentric wheel 50. This switching of the point of application is key to enabling the eccentric wheel 50 to switch between the two states of "locking preparation" and "unlocking hold".

[0052] The specific work process is as follows:

[0053] Locking preparation state: When the slider 30 is in the main adjustment section, the torsion spring 60 applies a preload force to the first abutment 52. The direction and point of application of this force are designed so that the torque it generates always drives the eccentric wheel body 51 to rotate toward the side wall of the track 21. For example, see... Figure 2 In the diagram, one end of the torsion spring 60 abuts against the first abutment portion 52 at the upper left, causing the eccentric wheel body 51 to face and adhere to the side wall of the track 21 on its left. Therefore, the outer edge of the eccentric wheel 50 can maintain contact with the side wall of the track 21, and once the sliding member 30 tends to slide along the preset locking direction, a wedge-shaped self-locking mechanism can be quickly formed. In one specific implementation, the first abutment portion 52 can be a protruding part extending from the side of the eccentric wheel body 51.

[0054] Unlocked and Retained State: When the slider 30 slides to the unlocking section, the eccentric wheel 50 rotates under the action of the first offset structure 22 and disengages from the side wall of the track 21, changing the relative position of the torsion spring 60 and the eccentric wheel 50. At this time, the point of action of the torsion spring 60 switches from the first abutment 52 to the second abutment 53. The torsion spring 60 applies a preload to the second abutment 53, which creates a "pulling" or "hooking" effect on the eccentric wheel 50, preventing it from rotating back to the position abutting against the side wall of the track 21. For example, one end of the torsion spring 60 abuts against the second abutment 53 to the right, causing the eccentric wheel body 51 to move away from the left side wall of the track 21. Therefore, during the process of the slider 30 returning from the unlocking section to the main adjustment section, the eccentric wheel 50 can continuously maintain a state of disengagement from the side wall of the track 21, thus ensuring a smooth and unobstructed return process. In one specific implementation, the second abutment 53 can be another protruding part extending from the side of the eccentric wheel body 51.

[0055] By setting a first abutment part 52 and a second abutment part 53, and enabling the torsion spring 60 to switch between these two points of action, the stepless adjustment mechanism 10 of this embodiment uses a single torsion spring 60 to achieve two completely opposite functions: "pushing" the eccentric wheel 50 to de-lock in the locking preparation state, and "pulling" the eccentric wheel 50 to prevent locking during the unlocking return process, thereby making the action logic of the entire mechanism clear, the structure compact and the reliability high.

[0056] In one embodiment, the fixing member 20 is further provided with a guide groove 24; the eccentric wheel 50 further includes a positioning part 54 provided on the eccentric wheel body 51, the positioning part 54 passing through the guide groove 24; the first offset structure 22 includes an inclined surface, the inclined surface of the first offset structure 22 is formed on one side wall of the guide groove 24; when the sliding member 30 slides to the unlocking section, the positioning part 54 abuts against the inclined surface of the first offset structure 22 and overcomes a preset resistance, so that the eccentric wheel 50 rotates around its pivot to disengage from the side wall of the track 21.

[0057] In this embodiment, in addition to the track 21, the fixing member 20 is also provided with a guide groove 24. The guide groove 24 can be arranged parallel to the track 21, and its function is to provide an additional guiding and constraint path for the eccentric wheel 50, thereby assisting in the control of the unlocking action. Specifically, the guide groove 24 can be formed on one surface of the fixing member 20.

[0058] Accordingly, the eccentric wheel 50 further includes a positioning part 54, which is located on the other side of the eccentric wheel body 51. If the first abutment part 52 and the second abutment part 53 are located on the front of the eccentric wheel body 51, then the positioning part 54 is located on the back of the eccentric wheel body 51. The positioning part 54 passes through the guide groove 24, that is, when the slider 30 slides along the track 21, the positioning part 54 is always located in the guide groove 24 and can move along the path of the guide groove 24. This passing relationship ensures that the eccentric wheel 50 is constrained by the guide groove 24 during the movement of the slider 30, thereby making the unlocking action more controllable and stable. In a specific implementation, the positioning part 54 can be a columnar structure that protrudes from the other side of the eccentric wheel body 51 and is parallel to the pivot of the eccentric wheel 50.

[0059] The first offset structure 22 specifically includes an inclined surface formed on one side wall of the guide groove 24. Specifically, this inclined surface is located at the position of the guide groove 24 corresponding to the unlocking section, and its inclination angle allows for gradual contact and guidance when the positioning part 54 slides along the guide groove 24 to this position. (See also...) Figure 5 The figure illustrates the location and shape of the inclined surface. For example, the inclined surface can extend inward from the sidewall of the guide groove 24 to form a ramp.

[0060] The unlocking process is implemented as follows: When the slider 30 slides along the track 21 from the main adjustment section to the unlocking section, the positioning part 54 of the eccentric wheel 50 moves along the guide groove 24 with the movement of the slider 30 until it contacts the inclined surface of the first offset structure 22. At this time, the positioning part 54 abuts against the inclined surface and needs to overcome a preset resistance under the continuous pushing force of the user. This preset resistance comes from the slope design of the inclined surface and the friction characteristics of the material. It ensures that the unlocking action does not occur arbitrarily, but requires a certain intentional force to trigger it. When the user operates, he / she can clearly perceive the process of overcoming the preset resistance, such as feeling a point of resistance change. This provides the user with clear operational feedback, informing him / her that the unlocking process has begun. After overcoming the resistance, the inclined surface guides the positioning part 54 to slide along its surface. This sliding is the lateral displacement of the positioning part 54 along the slope of the inclined surface. Since the positioning part 54 is part of the eccentric wheel body 51, and the eccentric wheel 50 is rotatable about its pivot, the lateral displacement of the positioning part 54 is directly converted into the rotation of the eccentric wheel 50 about its pivot. This rotation causes the outer edge of the eccentric wheel 50 to gradually detach from the side wall of the track 21, eventually completely disengaging, thus putting the eccentric wheel 50 into the unlocked state. In this unlocked state, the point of action of the torsion spring 60 also switches from the first abutment part 52 to the second abutment part 53, maintaining the unlocked state.

[0061] By introducing the guide groove 24, the positioning part 54, and the inclined surface of the first offset structure 22, this embodiment not only provides clear mechanical guidance and control for the unlocking rotation of the eccentric wheel 50, but also improves the sense of confirmation and reliability of operation through the preset resistance provided by the inclined surface, avoiding potential jamming or misoperation.

[0062] In this embodiment, the guide groove 24 has a stop wall at the end of the inclined surface of the first offset structure 22; the stop wall is configured to collide with the positioning part 54 when the positioning part 54 slides along the inclined surface to the end. This stop wall constitutes the physical boundary of one end of the guide groove 24, limiting the sliding stroke of the positioning part 54. In a specific implementation, the stop wall is an integrally formed wall surface at the end of the guide groove 24, with a collision surface formed on the side facing the positioning part 54.

[0063] The stop wall is configured to collide with the positioning part 54 of the eccentric wheel 50 in the final stage of the unlocking process. The specific working process is as follows: When the user pushes the slider 30 to the unlocking section, the positioning part 54 first contacts and slides along the inclined surface of the first offset structure 22. After overcoming the preset resistance, the eccentric wheel 50 rotates around its pivot and enters the unlocked state. If the user continues to push the slider 30, the positioning part 54 will continue to move along the guide of the inclined surface until the end of its sliding stroke, i.e., colliding with the stop wall at the end of the guide groove 24.

[0064] Since the positioning part 54 and the stop wall are made of materials with a certain degree of rigidity (such as metal or hard plastic), this collision will produce a clearly audible "click" sound or obvious tactile feedback (e.g., a sudden feeling of resistance). This sound and / or tactile signal serves as a clear indication to the user that the eccentric wheel 50 has completely disengaged from the side wall of the track 21, the entire mechanism has successfully entered the unlocked state, and a reverse (e.g., downward) reset operation can be safely performed.

[0065] By setting up a simple stop wall structure, this embodiment not only provides a clear physical endpoint for the unlocking action, preventing users from applying excessive force, but also greatly improves the convenience and certainty of user operation through the feedback signal generated by the collision, effectively avoiding misoperation caused by uncertainty about whether the unlocking is complete, thereby enhancing the reliability of the product and the user experience.

[0066] In one embodiment, the track 21 further includes a reset section located at the beginning of the main adjustment section stroke. The reset section is provided with a second offset structure 23, which includes another inclined surface. The inclined surface of the second offset structure 23 is formed on the other side wall of the guide groove 24. When the slider 30 returns from the unlocking section to the reset section, the positioning part 54 abuts against the inclined surface of the second offset structure 23 and overcomes another preset resistance to guide the eccentric wheel 50 back to the locking preparation state.

[0067] In this embodiment, in addition to the main adjustment section and the unlocking section, the track 21 further includes a reset section located at the beginning of the stroke of the main adjustment section. Here, the beginning of the stroke can be understood as another extreme position of the movement of the slider 30, corresponding to the unlocking section. This reset section is a key area in the return process after the mechanism completes unlocking, used to guide the eccentric wheel 50 back to its initial locking preparation state. At the reset section, a second offset structure 23 is provided, which is similar to the first offset structure 22, but operates in the opposite direction. Specifically, the second offset structure 23 includes another inclined surface, which is formed on the other side wall of the guide groove 24. Please refer to... Figure 5 The diagram illustrates the location of the reset section and the inclined surface of the second offset structure 23. For example, this inclined surface can extend inward from the other side wall of the guide groove 24, forming a ramp opposite to the inclined surface of the first offset structure 22. Its slope design ensures a gradual guiding effect during the return process.

[0068] The reset process is implemented as follows: When the slider 30 starts to return from the unlocking section of the track 21 (i.e., slides towards the main adjustment section), the eccentric wheel 50 is in the unlocked state (the torsion spring applies a preload to the second abutment part 53, and the eccentric wheel 50 remains detached from the side wall of the track 21). During this process, the positioning part 54 of the eccentric wheel 50 moves along the guide groove 24 until it enters the reset section and contacts the inclined surface of the second offset structure 23. At this time, the positioning part 54 abuts against the inclined surface and needs to overcome another preset resistance under the user's continuous pulling force. This preset resistance comes from the slope design of the inclined surface and the frictional characteristics of the material, similar to the resistance of the first offset structure 22, but in the opposite direction. It ensures that the reset action requires a certain intentional force, thereby avoiding accidental reset or jamming. When operating, the user can perceive the process of overcoming this preset resistance, for example, feeling a slight change in resistance, which provides the user with operational feedback, informing them that the mechanism is about to return to the locked ready state. After overcoming the resistance, the inclined surface guides the positioning part 54 to slide along its surface. This sliding is the lateral displacement of the positioning part 54 along the slope of the inclined surface. Since the positioning part 54 is part of the eccentric wheel body 51, and the eccentric wheel 50 can rotate about its pivot, the lateral displacement of the positioning part 54 is directly converted into the reverse rotation of the eccentric wheel 50 about its pivot. This rotation causes the outer edge of the eccentric wheel 50 to gradually move closer to the side wall of the track 21, eventually restoring contact with the side wall of the track 21. At the same time, the point of action of the torsion spring 60 switches from the second contact part 53 back to the first contact part 52, applying an initial preload to the eccentric wheel 50, thereby fully restoring the eccentric wheel 50 to the locked ready state. At this point, the mechanism is ready to enter the next adjustment cycle.

[0069] By introducing a reset section and an inclined surface of the second offset structure 23, this embodiment achieves a smooth transition from the unlocked state to the locked ready state. This not only provides mechanical guidance for the reset rotation of the eccentric wheel 50, but also enhances the reliability of operation and user perception through preset resistance, ensuring that the entire continuously variable adjustment mechanism 10 operates in a complete and efficient manner.

[0070] In one embodiment, the torsion spring 60 includes a torsion spring body 61 fixedly connected to the slider 30 and a hook 62 disposed on the torsion spring body 61; a loop path 100 is formed between the first abutment portion 52 and the second abutment portion 53, and the hook 62 is configured to move along the loop path 100 to abut against the first abutment portion 52 or the second abutment portion 53; wherein the starting point and the ending point of the loop path 100 are the same position of the first abutment portion 52.

[0071] like Figure 1 and Figure 2As shown, in this embodiment, the torsion spring 60 includes a torsion spring body 61 and a hook 62. The torsion spring body 61 is the main body of the torsion spring 60, and one end of it is fixedly connected to the inner wall of the sliding member 30 to ensure the stability of the torsion spring body 61 during the operation of the mechanism. The hook 62 is located at the other end of the torsion spring body 61 and is used to directly contact the first abutment part 52 or the second abutment part 53 on the eccentric wheel 50, thereby applying a corresponding preload. The hook 62 has a certain elastic deformation capability to adapt to the state switching during the unlocking process.

[0072] Correspondingly, a loop path 100 is formed between the first abutment portion 52 and the second abutment portion 53 on the eccentric wheel 50. This loop path 100 is a closed, continuous path structure. Specifically, the first abutment portion 52 can be an arc-shaped protrusion, and the second abutment portion 53 can be an adjacent limiting (irregular) protrusion. The first abutment portion 52, the second abutment portion 53, and the gap between them together define the loop path 100, and these two abutment portions constitute the points of application for the hook 62 to apply force in different states. The starting and ending points of the loop path 100 are both at the same position of the first abutment portion 52, meaning that after completing a full sliding cycle, the hook 62 will return to the initial abutment point, thus achieving a cyclical switching of states. Please refer to [link / reference]. Figure 2 The multiple arrows in the figure illustrate the shape and position of the loop path 100, which is an irregular loop path, in which the first abutment 52 is located at the low point of the path and the second abutment 53 is located at the relatively high point of the path. Figure 2 The multiple hooks shown do not appear at the same time, but rather indicate that they are at three different locations on the loop path 100.

[0073] The specific implementation of state switching is as follows:

[0074] When the eccentric wheel 50 is in the locking preparation state, the hook 62 abuts against the first abutment part 52. At this time, the preload applied by the torsion spring 60 acts on the first abutment part 52 through the hook 62, generating a torque that drives the eccentric wheel body 51 to abut against the side wall of the track 21, preparing for wedge self-locking.

[0075] When the user operates the slider 30 to enter the unlocking section, the eccentric wheel 50 rotates from the locked preparation state to the unlocked state. The rotation of the eccentric wheel 50 causes the abutment portion on it to move relative to the fixed torsion spring body 61. During this process, the hook 62 first moves along the surface of the first abutment portion 52 and eventually disengages from the first abutment portion 52. After disengagement, the hook 62 moves away from the gap between the first abutment portion 52 and the second abutment portion 53 due to its own elasticity. As the eccentric wheel 50 continues to rotate, the hook 62 will come to the vicinity of the second abutment portion 53. During this process, the hook 62 does not actively come to the vicinity of the second abutment portion 53, but rather the second abutment portion 53 actively approaches the hook 62 under the rotation of the eccentric wheel 50, until the hook 62 touches the top of the second abutment portion 53 and passes over the top (this is a high point, which needs to overcome the elastic resistance of the torsion spring 60 itself). After passing the top, the eccentric wheel 50 continues to rotate slightly until the hook 62 completely moves to the side of the second abutment portion 53 and stably abuts against that side. At this time, the hook 62 is in an unnatural state, and the torsion spring 60 applies a preload force to the side of the second abutment 53 through the hook 62. The direction of this force generates a torque opposite to the previous one, which "pulls" or "hooks" the eccentric wheel 50, so that it is reliably kept in the unlocked state disengaged from the side wall of the track 21.

[0076] When the user operates the slider 30 back to the reset position, and the eccentric wheel 50 rotates from the unlocked state to the locked ready state, the reverse rotation of the eccentric wheel 50 will also cause relative movement of the abutment portion on it. During this process, the hook 62 will first move along the side of the second abutment portion 53 and eventually disengage from the second abutment portion 53. After disengagement, as the eccentric wheel 50 continues to rotate, the hook 62 will then return and re-abut against the first abutment portion 52 (i.e., the start and end positions of the cycle path 100). Once the hook 62 abuts against the first abutment portion 52, the preload of the torsion spring 60 will act again in the initial manner, causing the eccentric wheel 50 to return to the locked ready state, thus completing a complete operation cycle.

[0077] Through the above-described motion path design of hook 62, this embodiment utilizes the cooperation between a single torsion spring 60 and the positions of the two abutting parts to achieve a clear and reliable switching between two working states without the need for other additional complex mechanisms. This simplifies the overall structural design and improves the stability of the mechanism and the user experience.

[0078] In this embodiment, the surfaces of the first abutment 52 and the second abutment 53 are both arc surfaces. Moreover, a ramp 101 is provided on the main body of the eccentric wheel 50 at the middle position of the surface of the second abutment 53. The surface of the ramp 101 is an inclined surface, which can prevent the hook 62 abutting the surface of the second abutment 53 from disengaging from the second abutment 53 without external force. When the eccentric wheel 50 touches the second offset structure 23, the main body of the eccentric wheel 50 actively disengages from the hook 62. At this time, the hook 62 crosses the ramp 101 and comes to the first abutment 52 along the second abutment 53.

[0079] In one embodiment, the device further includes an outer tube 70 and an inner tube 80, wherein the inner tube 80 is slidably disposed within the outer tube 70; the fixing member 20 is fixedly disposed on the inner wall of the outer tube 70; the outer wall of the inner tube 80 is provided with a receiving groove 81 along the length direction, and the sliding member 30 is fixedly disposed within the receiving groove 81 and located between the fixing member 20 and the inner tube 80.

[0080] like Figure 7 and Figure 8 As shown, in this embodiment, the stepless adjustment mechanism 10 further includes an outer tube 70 and an inner tube 80. The outer tube 70 is a cylindrical structure that can serve as the outer shell of the mechanism or a fixed support component, for example, fixed to the backrest support 91 of a seat. The inner tube 80 is a tubular component that matches the outer tube 70, with an outer diameter smaller than the inner diameter of the outer tube 70, thereby allowing it to slide within the outer tube 70 and achieve relative telescopic movement along its length. This telescopic relationship forms the basis of the mechanism's adjustment stroke, and the user can adjust the position by pulling the inner tube 80 relative to the outer tube 70.

[0081] The fastener 20 is fixedly disposed on the inner wall of the outer tube 70. Specifically, the fastener 20 can be installed on the inner side wall of the outer tube 70 with screws to ensure that it remains stationary during the operation of the mechanism. The track 21 and guide groove 24 on the fastener 20 face the inner tube 80.

[0082] The outer wall of the inner tube 80 is provided with a receiving groove 81 along its length. This receiving groove 81 is a recessed structure formed on the outer surface of the inner tube 80, used to accommodate and fix the sliding member 30. The sliding member 30 is fixedly disposed within the receiving groove 81 and located between the fixing member 20 and the inner tube 80. Specifically, the sliding member 30 is embedded in the receiving groove 81 and fixedly connected to the inner tube 80 by fasteners, thereby allowing the sliding member 30 to move with the extension and retraction of the inner tube 80. Simultaneously, since the sliding member 30 is located between the fixing member 20 and the inner tube 80, its locking components (including the eccentric wheel 50 and the torsion spring) can directly interact with the track 21 and guide groove 24 on the fixing member 20. The sliding member 30 is embedded in the receiving groove 81 of the inner tube 80 and faces the track 21 of the fixing member 20 through its opening 32.

[0083] In actual operation, when the user adjusts the telescopic position of the inner tube 80 relative to the outer tube 70, the inner tube 80 drives the sliding member 30 to slide along the track 21 on the fixed member 20. Specifically:

[0084] Within the main adjustment section, the sliding member 30 moves with the movement of the inner tube 80, and the eccentric wheel 50 abuts against the side wall of the track 21 under the preload of the torsion spring 60. Once the inner tube 80 tends to move in the preset locking direction, a wedge-shaped self-locking is formed, thereby locking the inner tube 80 at any position.

[0085] When the inner tube 80 is stretched to its limit position (corresponding to the sliding member 30 entering the unlocking section), the positioning part 54 of the eccentric wheel 50 abuts against the inclined surface of the first offset structure 22, and after overcoming the preset resistance, it guides the eccentric wheel 50 to rotate and disengage from the side wall of the track 21, so that the mechanism enters the unlocking state.

[0086] During the return process, the inner tube 80 retracts, causing the sliding component 30 to return from the unlocking section to the main adjustment section, while the eccentric wheel 50 remains in the disengaged state until it returns to the locked ready state.

[0087] By introducing the telescopic structure of the outer tube 70 and the inner tube 80, and the receiving groove 81 on the inner tube 80 to fix the sliding member 30, the stepless adjustment mechanism 10 of this embodiment achieves a compact assembly design, making the adjustment action smoother and easier to integrate into products such as seats, thereby improving the overall structural stability and adjustment accuracy.

[0088] In one embodiment, the fastener 20 has an L-shaped structure, including a mounting portion 25 and a guide rail portion 26 disposed perpendicularly to the mounting portion 25; the rail 21 is formed on the guide rail portion 26, and the guide groove 24 is disposed on the mounting portion 25.

[0089] like Figure 4 and Figure 5 As shown, in this embodiment, the fastener 20 has an L-shaped structure. This L-shaped design gives the fastener 20 two mutually perpendicular planes, which makes it easier to fit and install it against the inner wall of the outer tube 70, and can effectively utilize space to integrate different functions. Specifically, the fastener 20 includes a mounting part 25 and a guide rail part 26 that is perpendicular to the mounting part 25.

[0090] The mounting portion 25 is a planar part of the fixing member 20, used to connect the fixing member 20 to the outer tube 70. For example, the mounting portion 25 can fit tightly against the inner wall of the outer tube 70 and be firmly fixed inside the outer tube 70 by means of screws, riveting, or welding, ensuring that the fixing member 20 remains in a stable position throughout the adjustment process. The mounting portion 25 provides a reliable reference for the entire stepless adjustment mechanism 10.

[0091] The guide rail portion 26 is another planar part of the fixing member 20, and its surface is perpendicular to the mounting portion 25. The guide rail portion 26 is the main functional area for achieving sliding and locking. Specifically, the track 21 (including the main adjustment section, the unlocking section, and the reset section) is formed on the guide rail portion 26. The track 21 is the surface of the guide rail portion 26, and its wall surface is used to abut against the eccentric wheel 50 to achieve wedge-shaped self-locking.

[0092] Furthermore, the guide groove 24 is provided on the mounting portion 25. By placing the guide groove 24 on the mounting portion 25, which is perpendicular to the guide rail portion 26, the spatial layout of the L-shaped structure can be fully utilized. The positioning portion 54 on the eccentric wheel 50 passes through the slider 30 and extends into the guide groove 24 on the mounting portion 25. This arrangement ensures that when the eccentric wheel 50 slides along the track 21 on the guide rail portion 26, its rotation is controlled by the guide groove 24 on the mounting portion 25, achieving functional separation and cooperation.

[0093] In summary, by designing the fixing member 20 as an L-shaped structure and setting the rail 21 and guide groove 24 on the guide rail part 26 and the mounting part 25 respectively, this embodiment not only optimizes the installation stability and space utilization of the fixing member 20, but also makes the functional distribution of sliding adjustment (along the guide rail part) and unlocking / resetting control (through the guide groove on the mounting part 25) clearer and more reasonable, thereby improving the structural strength and operating accuracy of the entire stepless adjustment mechanism 10.

[0094] In one embodiment, the outer wall of the inner tube 80 is further provided with a limiting groove 82, and a limiting part 261 extends from the guide rail 26. The limiting part 261 is slidably disposed in the limiting groove 82 to limit the sliding stroke of the inner tube 80.

[0095] like Figure 7 and Figure 8 As shown, in this embodiment, a limiting groove 82 is also provided on the outer wall of the inner tube 80. The limiting groove 82 is a groove extending along the length of the inner tube 80, and its length determines the maximum adjustable range of the inner tube 80 relative to the outer tube 70. The two ends of the limiting groove 82 (i.e., the start and end points of the groove) constitute the physical boundary of the movement of the inner tube 80.

[0096] Accordingly, a limiting part 261 extends from the guide rail portion 26 of the fixing member 20. The limiting part 261 can be a boss structure integrally formed from the edge of the guide rail portion 26. During assembly, the limiting part 261 is directly disposed in the limiting groove 82 of the inner tube 80 and can slide in the limiting groove 82 as the inner tube 80 extends or retracts.

[0097] The specific work process is as follows:

[0098] When the user pulls the inner tube 80 outward, the limiting part 261 on the fixing member 20 slides within the limiting groove 82 (actually, the limiting groove 82 slides relative to the limiting part 261 on the fixing member 20). When the limiting part 261 is at one end of the limiting groove 82, it abuts against the end wall of the limiting groove 82, thereby preventing the inner tube 80 from being pulled out further and preventing the inner tube 80 from accidentally separating from the outer tube 70. At this time, the position of the sliding member 30 also corresponds to the unlocking section on the track 21, realizing the synchronization of the end of the stroke and the unlocking function.

[0099] When the user retracts the inner tube 80 inward, the limiting part 261 also slides within the limiting groove 82. When the limiting part 261 moves to the other end of the limiting groove 82, it abuts against the end wall, thereby preventing the inner tube 80 from being pushed further in and ensuring that the mechanism is not damaged due to excessive compression. At this time, the position of the sliding member 30 also corresponds to the reset section on the track 21, realizing the synchronization of the start of the stroke and the reset function.

[0100] By providing a limiting groove 82 on the inner tube 80 and extending a corresponding limiting part 261 on the guide rail part 26 of the fixing member 20, this embodiment integrates the stroke limiting function using existing components. This design is not only simple and reliable in structure, but also allows for easy definition of the effective sliding stroke of the inner tube 80 by setting the length of the limiting groove 82, ensuring that the entire telescopic adjustment mechanism operates within a preset safety range, thereby improving the product's durability and user safety.

[0101] In one embodiment, the sliding member 30 is a box with an inner cavity. The box has an opening 32 on the side near the guide rail 26, and the eccentric wheel 50 abuts against the side wall of the rail 21 through the opening 32. The box has a guide groove 33 on the side near the mounting part 25, and the positioning part 54 passes through the guide groove 33 and is inserted into the guide groove 24.

[0102] like Figure 6 As shown, in this embodiment, the sliding member 30 is specifically designed as a box with an inner cavity. This box is a hollow shell structure used to house the locking assembly (including components such as the eccentric wheel 50 and the torsion spring 60). The overall shape of the box matches the receiving groove 81 of the inner tube 80, facilitating its fixed installation on the inner tube 80.

[0103] The housing has an opening 32 on the side near the guide rail 26. This opening 32 is an open window structure located on the side of the housing facing the guide rail of the fixing member 20. Through this opening 32, part of the outer edge of the eccentric wheel 50 can extend out of the housing and directly abut against the side wall of the rail 21 on the guide rail 26. Specifically, in the locking preparation state, the eccentric wheel 50, under the preload of the torsion spring 60, maintains contact with the side wall of the rail 21 through the opening 32; once a force in a preset locking direction is applied, the eccentric wheel 50 forms a wedge-shaped self-locking mechanism through the opening 32. This opening 32 design makes the locking action direct and efficient, while the housing itself does not interfere with the interaction between the eccentric wheel 50 and the rail 21.

[0104] A guide groove 33 is provided on the side of the housing near the mounting part 25. This guide groove 33 is designed to be short, with neither end extending to the opposite sides of the housing. Its length limits the rotation angle of the eccentric wheel 50, ensuring that the eccentric wheel 50 can properly self-lock with the side wall of the track 21, and also facilitating reset in the unlocked state. The guide groove 33 is located on the side of the housing facing the mounting part of the fixing member 20, and its position corresponds to the guide groove 24 on the mounting part 25. The positioning part 54 on the eccentric wheel 50 passes through the guide groove 33 and into the guide groove 24. Specifically, the positioning part 54 extends from the eccentric wheel body 51, first passes through the guide groove 33 on the housing, and then further extends into the guide groove 24 on the mounting part of the fixing member 20. This through-and-through relationship ensures that the positioning part is simultaneously guided by both the guide groove 33 and the guide groove 24 during the movement of the sliding member 30, thereby controlling the rotation and displacement of the eccentric wheel 50. During the unlocking or reset process, the positioning part 54 moves along the path of the guide groove 33 and the guide groove 24 and comes into contact with the inclined surface of the first offset structure 22 or the second offset structure 23 to achieve state switching.

[0105] By designing the slider 30 as a box with an inner cavity and providing an opening 32 and a guide groove 33 on a specific side, this embodiment not only provides a space for the internal locking components, but also optimizes the functional cooperation with the guide rail and mounting part 25 of the fixing part 20, ensuring the accuracy and stability of the eccentric wheel 50 in the locking, unlocking and resetting process, and improving the assembly convenience and operational reliability of the entire stepless adjustment mechanism 10.

[0106] Figure 9 A schematic diagram of the backrest support and lumbar support provided in an embodiment of this utility model. Figure 9 As shown, corresponding to the above-mentioned stepless adjustment mechanism, this utility model embodiment also provides a chair back, which includes a backrest support 91 and an adjustable component. The stepless adjustment mechanism 10 as described in the previous embodiment is provided between the backrest support 91 and the adjustable component; wherein, the adjustable component is a lumbar support 92 or a backrest body.

[0107] In this embodiment, the chair back includes a backrest support 91 and an adjustable component. The backrest support 91 is the main frame of the chair back, used to support the user's back, and is connected to other parts of the seat (such as the seat cushion or chassis). The adjustable component is a part that can move relative to the backrest support 91, and it can specifically be a lumbar support 92 (used to support the user's waist and provide fore-and-aft adjustment) or the main backrest body (used for overall height adjustment, not shown separately in the accompanying drawings).

[0108] A stepless adjustment mechanism 10 is provided between the backrest support 91 and the adjustable component. Specifically, the outer tube 70 of the stepless adjustment mechanism 10 can be fixedly mounted on the backrest support 91, while the inner tube 80 is fixedly connected to the adjustable component. Through this connection, when the user adjusts the position of the adjustable component, the inner tube 80 will extend or retract relative to the outer tube 70, causing the sliding member 30 to slide along the track 21 on the fixed member 20, thereby realizing the aforementioned locking, unlocking, and reset functions.

[0109] In one application scenario, when the adjustable component is the lumbar support 92, the mechanism allows for stepless forward and backward adjustment of the lumbar support 92: when the user pulls the lumbar support 92 forward, the inner tube 80 drives the slider 30 to slide along the track 21 towards the main adjustment section. Releasing the lumbar support 92 at any position triggers the wedge-shaped self-locking of the eccentric wheel 50 due to its own weight or the user's leaning force. Pulling it to its limit position enters the unlocking section, where the eccentric wheel 50 disengages from the side wall of the track 21, allowing the user to return the lumbar support 92 to its original position until the reset section returns to the locked state. This design allows users to precisely adjust the position of the lumbar support 92 according to their body shape, improving comfort.

[0110] In another application scenario, when the adjustable component is the backrest body, this mechanism enables stepless adjustment of the backrest body's height: when the user lifts the backrest body upwards, the inner tube 80 drives the slider 30 to slide upwards along the track 21; releasing the hand at any height triggers a self-locking mechanism due to its own weight; when lifted to the top, it enters the unlocking section, the eccentric wheel 50 unlocks, and the user can lower the backrest body back to its original position until the bottom is locked. This design provides millimeter-level precision adjustment, superior to traditional stepped adjustment.

[0111] By integrating the aforementioned stepless adjustment mechanism 10 between the backrest support 91 and the adjustable component, the chair back of this embodiment achieves smooth locking at any position and efficient operation with a short stroke. At the same time, the secondary unlocking mechanism improves operational reliability and user experience, making it suitable for products such as office chairs.

[0112] The above description is merely a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this utility model, and these modifications or substitutions should all be covered within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the scope of the claims.

Claims

1. A stepless adjustment mechanism, characterized in that, include: A fixing component is provided with a track, the track including a main adjustment section and an unlocking section located at the end of the stroke of the main adjustment section, and the unlocking section is provided with a first offset structure; The slider can slide along the track between the main adjustment section and the unlocking section; A locking assembly is disposed within the slider, the locking assembly including an eccentric wheel pivotally connected to the slider and a torsion spring for applying a preload to the eccentric wheel; When the slider is located in the main adjustment section and the eccentric wheel is in the locking preparation state, the torsion spring drives the eccentric wheel to abut against the side wall of the track, and when the slider is subjected to a force in a preset locking direction, the eccentric wheel and the side wall of the track form a wedge-shaped self-locking mechanism. When the slider slides to the unlocking section, the first offset structure guides the eccentric wheel to disengage from the track sidewall, so that the eccentric wheel is in the unlocked state; When the slider returns from the unlocking section to the main adjustment section, the torsion spring drives the eccentric wheel to remain disengaged from the track sidewall until the eccentric wheel returns to the locking ready state.

2. The stepless adjustment mechanism according to claim 1, characterized in that, The eccentric wheel includes an eccentric wheel body and a first abutting portion and a second abutting portion disposed on the eccentric wheel body; the torsion spring is configured to abut against the first abutting portion or the second abutting portion to apply a corresponding preload. When the torsion spring drives the eccentric wheel to abut against the side wall of the track, the torsion spring applies a preload to the first abutment portion; when the torsion spring drives the eccentric wheel to remain detached from the side wall of the track, the torsion spring applies a preload to the second abutment portion.

3. The stepless adjustment mechanism according to claim 2, characterized in that, The fixing member is also provided with a guide groove; the eccentric wheel also includes a positioning part provided on the eccentric wheel body, the positioning part passing through the guide groove; the first offset structure includes an inclined surface, the inclined surface of the first offset structure is formed on one side wall of the guide groove; when the sliding member slides to the unlocking section, the positioning part abuts against the inclined surface of the first offset structure and overcomes a preset resistance, so that the eccentric wheel rotates around its pivot to disengage from the side wall of the track.

4. The stepless adjustment mechanism according to claim 3, characterized in that, The track also includes a reset section located at the beginning of the main adjustment section stroke. The reset section is provided with a second offset structure, which includes another inclined surface. The inclined surface of the second offset structure is formed on the other side wall of the guide groove. When the slider returns from the unlocking section to the reset section, the positioning part abuts against the inclined surface of the second offset structure and overcomes another preset resistance to guide the eccentric wheel back to the locking preparation state.

5. The stepless adjustment mechanism according to claim 4, characterized in that, The torsion spring includes a torsion spring body fixedly connected to the sliding member and a hook disposed on the torsion spring body; a loop path is formed between the first abutment portion and the second abutment portion, and the hook is configured to move along the loop path to abut against the first abutment portion or the second abutment portion; wherein the starting point and the ending point of the loop path are the same position of the first abutment portion.

6. The stepless adjustment mechanism according to claim 3, characterized in that, It also includes an outer tube and an inner tube, the inner tube being slidably disposed within the outer tube; the fixing member being fixedly disposed on the inner wall of the outer tube; the outer wall of the inner tube is provided with a receiving groove along the length direction, the sliding member being fixedly disposed within the receiving groove and located between the fixing member and the inner tube.

7. The stepless adjustment mechanism according to claim 6, characterized in that, The fastener has an L-shaped structure and includes a mounting part and a guide rail part arranged perpendicularly to the mounting part; the rail is formed on the guide rail part, and the guide groove is provided on the mounting part.

8. The stepless adjustment mechanism according to claim 7, characterized in that, The outer wall of the inner tube is also provided with a limiting groove, and a limiting part extends from the guide rail. The limiting part is slidably disposed in the limiting groove to limit the sliding stroke of the inner tube.

9. The stepless adjustment mechanism according to claim 7, characterized in that, The sliding member is a box with an inner cavity. The box has an opening on the side near the guide rail. The eccentric wheel abuts against the side wall of the rail through the opening. The box has a guide groove on the side near the mounting part. The positioning part passes through the guide groove.

10. A chair back, characterized in that, It includes a backrest support and an adjustable component, wherein a stepless adjustment mechanism as described in any one of claims 1 to 9 is provided between the backrest support and the adjustable component; wherein the adjustable component is a lumbar support or a backrest body.

Images