Backrest front-back adjusting mechanism and seat
By designing a sliding fit between the mounting bracket and the support, and combining the locking block, adjustment button, and elastic element, the seat backrest can be adjusted with one hand, solving the problem of cumbersome operation in the existing technology and improving the convenience of adjusting the seat backrest.
Patent Information
- Application Number
- CN202520598443.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-31
- Publication Date
- 2026-02-10
- Estimated Expiration
- 2035-03-31
AI Technical Summary
The existing seat backrest adjustment mechanism is cumbersome to operate, requiring both hands to coordinate the adjustment buttons and mounting bracket, making it inconvenient to use.
Design a backrest front and back adjustment mechanism. Through the sliding cooperation between the mounting bracket and the support, combined with the design of the locking block, adjustment button and elastic element, the backrest front and back adjustment can be operated with one hand. The movement direction of the adjustment button and the mounting bracket is the same as the movement direction of the mounting bracket relative to the support, simplifying the operation process.
The seat backrest adjustment process is simple and convenient, and can be completed with one hand, improving the user experience.
Smart Images
Figure CN223886554U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of seat technology, specifically to a backrest front-to-back adjustment mechanism and a seat. Background Technology
[0002] Traditional chairs have fixed backrests and seat cushions, making it difficult to accommodate different sitting postures and body shapes. To improve comfort, some office chairs and child chairs typically feature adjustable backrests, allowing users to adjust the backrest position as needed. However, current backrest adjustment mechanisms involve operating adjustment buttons to adjust and lock the backrest. Specifically, a mounting bracket on the back of the seat is attached to the chair frame and has the freedom to slide back and forth relative to the frame. Operating the adjustment button moves the locking block in the vertical or horizontal direction. Because the movement of the adjustment button and the movement of the mounting bracket relative to the frame are perpendicular, users need to press the adjustment button with one hand and move the backrest or the mounting bracket with the other, making the adjustment process rather cumbersome. Utility Model Content
[0003] The purpose of this utility model is to provide a backrest front-back adjustment mechanism and a seat, which can adjust the front-back position of the backrest with one hand, and the adjustment process is simple and convenient.
[0004] To achieve the above objectives, the present invention adopts the following technical solution:
[0005] The backrest fore-and-aft adjustment mechanism includes a mounting bracket connected to the backrest, a bracket connected to the seat, a locking block, and an adjustment button;
[0006] The mounting bracket and the support slide together so that the mounting bracket can move relative to the support in the front-back direction. The mounting bracket is provided with multiple slots arranged in the front-back direction.
[0007] The locking block is movably mounted on the bracket, and a first elastic element is provided between the locking block and the bracket. The first elastic element is used to push the locking block toward the mounting bracket so that the locking block can be locked into one of the locking slots.
[0008] The adjustment button is equipped with an operating end and multiple protrusions arranged in the front-back direction. Each protrusion corresponds to a slot. The adjustment button slides with the mounting bracket to allow the adjustment button to move back and forth between a first position and a second position. When the adjustment button is in the first position, the protrusion is located behind its corresponding slot. When the adjustment button is in the second position, the protrusion and its corresponding slot overlap in the front-back direction.
[0009] A second elastic element is provided between the adjustment button and the mounting bracket. The second elastic element is used to apply elastic stress to the adjustment button so that the adjustment button always has the tendency to move towards the first position. The operating end is used to drive the adjustment button to move from the first position to the second position. During the process of the adjustment button moving from the first position to the second position, the protrusion moves forward with the adjustment button and pushes the locking block away from the square of the mounting bracket so that the locking block disengages from the locking groove.
[0010] The inner wall of the locking groove forms a stop and a pusher located behind the stop. The stop is used to cooperate with the locking block to limit the rearward movement of the mounting bracket relative to the locking block when the locking block is engaged in the locking groove. The pusher is used to push the locking block away from the mounting bracket when the mounting bracket moves forward relative to the bracket, so that the locking block is disengaged from the locking groove.
[0011] Preferably, the mounting bracket includes a lower mounting base, multiple slots are provided on the lower surface of the lower mounting base, and a sliding groove extending from the upper surface to the lower surface of the lower mounting base is provided on the lower mounting base. An adjustment button is located above the lower mounting base, and a protrusion extends downward from the lower surface of the adjustment button and slides through the sliding groove.
[0012] Preferably, the stop portion is a limiting wall extending upward from the lower surface of the lower mounting base, and the pushing portion is an inclined guide wall. The top end of the inclined guide wall is connected to the top end of the limiting wall plate, and the bottom end is connected to the lower surface of the lower mounting base. The inclined guide wall gradually slopes backward from top to bottom.
[0013] Preferably, the protrusion includes a pressing surface on its front side, a top pressing surface on its bottom side, and a stop surface on its rear side. The pressing surface gradually slopes backward from top to bottom, and the stop surface extends in the vertical direction. The two ends of the top pressing surface are respectively connected to the bottom of the pressing surface and the stop surface and are flush with the lower surface of the lower mounting base. When the adjustment button is in the first position, the pressing surface on the protrusion is flush with the inclined guide wall on the locking groove, and the stop surface on the protrusion is flush with the limiting wall of the locking groove located on the rear side of the protrusion.
[0014] Preferably, the front end of the slide groove forms a front end surface and the rear end forms a rear end surface. When the adjustment button is in the first position, its rear part abuts against the rear end surface, and when the adjustment button is in the second position, its front part abuts against the front end surface.
[0015] Preferably, the slide groove passes through multiple locking slots from front to back to divide the locking slots into two parts located on both sides of the slide groove; the part of the adjustment button located in front of each protrusion forms a relief part. When the adjustment button is in the first position, the locking slot corresponding to the protrusion and the relief part located in front of the protrusion are aligned and together form a groove.
[0016] Preferably, the bracket is provided with a mounting groove extending in the vertical direction, the locking block is slidably embedded in the mounting groove, and the first elastic element is located in the mounting groove; the top of the locking block forms a locking end, the front side of the locking end forms a stop wall extending vertically, and the rear side forms a mating slope, which gradually slopes backward from top to bottom.
[0017] Preferably, the mounting bracket also includes an upper mounting base located above the lower mounting base. The upper mounting base and the lower mounting base are detachably fitted together to form a mounting chamber. The adjustment button is located in the mounting chamber, and the rear end of the adjustment button protrudes from the rear of the mounting chamber to form an operating end located outside the mounting bracket.
[0018] Preferably, the lower mounting base and the upper mounting base each form an outward-facing guide groove on both sides, the bracket is located below the lower mounting base, and the bracket has sliders protruding towards the inside of the bracket on both sides, and the two sliders are slidably embedded in the two guide grooves.
[0019] The seat includes the aforementioned backrest fore-and-aft adjustment mechanism.
[0020] Compared with the prior art, the beneficial effects of this utility model are as follows:
[0021] In this invention, when the seat back needs to be adjusted forward, simply move the mounting bracket forward relative to the support. Once the mounting bracket is moved to the predetermined position, the locking block will engage with the corresponding slot on the mounting bracket. When the seat back needs to be adjusted backward, the adjustment button is designed to move back and forth relative to the mounting bracket, and its direction of movement is the same as the direction of movement of the mounting bracket relative to the support. The user can operate the adjustment button and move the mounting bracket simultaneously with one hand. Thus, the forward and backward movement of the seat back can be operated with one hand, making the adjustment of the seat back simple and convenient. Attached Figure Description
[0022] Figure 1 This is a schematic diagram of the structure of this utility model;
[0023] Figure 2 This is a cross-sectional view of the present invention;
[0024] Figure 3-5 This is a schematic diagram of the usage state of this utility model;
[0025] Figure 6 for Figure 2 Schematic diagram of the middle and lower mounting base;
[0026] Figure 7 for Figure 2 A schematic diagram of the structure of the adjustment button;
[0027] Figure 8 for Figure 2A schematic diagram of the structure of the central support.
[0028] Wherein: 100, mounting bracket; 10, lower mounting seat; 11, locking groove; 111, inclined guide wall; 112, limiting wall; 12, sliding groove; 121, front end face; 122, rear end face; 20, upper mounting seat; 30, adjustment button; 301, protruding rib; 302, first end face; 303, second end face; 31, protrusion; 311, pressing surface; 312, top pressing surface; 313, stop surface; 32, clearance part; 33, operating end; 40, bracket; 41, mounting groove; 42, slider; 50, locking block; 51, locking end; 511, mating inclined surface; 512, stop wall; 60, first spring; 70, second spring; 90, seat back. Detailed Implementation
[0029] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments. Unless otherwise specified, the materials and equipment used in this embodiment are all commercially available. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.
[0030] In the description of this application, it should be understood that the terms "upper," "lower," "front," "rear," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. In the description of this application, "a plurality of" means two or more, unless otherwise precisely specified.
[0031] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "connected," "linked," and "connected" should be interpreted broadly. For example, they can refer to a fixed connection, a connection through an intermediary, or a connection within two elements or an interaction between two elements. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.
[0032] like Figure 1 , 2As shown in figures 3, 4, 5, 6, 7, and 8, this utility model discloses a backrest fore-and-aft adjustment mechanism. It is mounted on a seat to achieve fore-and-aft adjustment of the seat backrest 90. Specifically, the adjustment mechanism includes a mounting bracket 100, a support 40, a locking block 50, and an adjustment button 30. The seat backrest 90 is connected to the mounting bracket 100, and the support 40 is mounted on the seat cushion. The mounting bracket 100 and the support 40 are slidably engaged, allowing the mounting bracket 100 to move relative to the support 40 in the fore-and-aft direction. This allows the seat backrest 90 to adjust forward and backward. The mounting bracket 100 has multiple locking slots 11 arranged in the front-rear direction, allowing for freedom of movement in the rearward direction. A bracket 40 is located below the mounting bracket 100, and a locking block 50 is located below the mounting bracket 100 and movably mounted on the bracket 40. The locking block 50 can move vertically relative to the bracket 40. A first spring 60 is provided between the locking block 50 and the bracket 40. The elastic stress provided by the first spring 60 pushes the locking block 50 upward, ensuring that the locking block 50 always maintains an upward movement tendency, thereby enabling the locking block 50 to... The adjustment button 30 is inserted into one of the slots 11. The adjustment button 30 has an operating end 33 and multiple protrusions 31 arranged in the front-to-back direction. Each protrusion 31 corresponds to a slot 11. Specifically, the adjustment button 30 is movably mounted on the mounting bracket 100. After the adjustment button 30 is mounted on the mounting bracket 100, the multiple protrusions 31 on the adjustment button 30 correspond one-to-one with the multiple slots 11 on the mounting bracket 100. The adjustment button 30 slides against the mounting bracket 100 so that the adjustment button 30 can move relative to the mounting bracket 100 in the front-to-back direction. The mounting bracket 100 moves, and the range of forward and backward movement of the adjustment button 30 is limited by the mounting bracket 100, so that the adjustment button 30 can move between a first position located at the rear and a second position located at the front. When the adjustment button 30 is in the first position, the protrusion 31 is located on the rear side of its corresponding slot 11. When the adjustment button 30 is in the second position, the position of the protrusion 31 is forward compared to the first position, that is, compared to the first position, the protrusion 31 moves forward by a certain displacement. In this way, in the forward and backward direction, the protrusion 31 and its corresponding slot 11 coincide.A second spring 70 is provided between the adjustment button 30 and the mounting bracket 100. The elastic stress provided by the second spring 70 makes the adjustment button 30 always tend to move towards the first position, that is, the elastic stress provided by the second spring 70 makes the adjustment button 30 always tend to move backward. The operating end 33 is used to drive the adjustment button 30 from the first position to the second position. That is, when the user operates the operating end 33, the adjustment button 30 can be moved forward. Due to the elastic stress generated by the second spring 70, the adjustment button 30 always remains in the first position when no external force is received. When the operating end 33 is operated and the adjustment button 30 moves towards the second position, that is, when the protrusion 31 moves forward with the adjustment button 30, the protrusion 31 can push the locking block 50 located in the locking groove 11 away from the mounting bracket 100. That is, the locking block 50 is pushed by the protrusion 31, causing the locking block 50 to move downward, and then the locking block 50 can be disengaged from the locking groove 11. The inner wall of the locking groove 11 forms a stop and a pushing part. The pushing part is located behind the stop and cooperates with the locking block 50. When the locking block 50 is locked in the locking groove 11, the stop abuts against the front side of the locking block 50, limiting the degree of freedom of the mounting bracket 100 to move backward relative to the locking block 50. At this time, the seat back 90 is in a normal working state, that is, it can withstand the pressure from the user's back, ensuring that the seat back 90 will not move backward when it bears the pressure from the user's back. The pushing part is used to push the locking block 50 away from the mounting bracket 100 when the mounting bracket 100 moves forward relative to the bracket 40. That is, when the user pushes the mounting bracket 100 forward, the pushing part of the inner wall of the locking groove 11 can push the locking block 50 out of the locking groove 11, so that the locking block 50 is disengaged from the locking groove 11.
[0033] like Figure 2 As shown, the first spring 60 pushes the locking block 50 upward, causing its upper part to embed into one of the locking slots 11. At this time, the locking block 50 cooperates with the stop in the locking slot 11, limiting the degree of freedom of the mounting bracket 100 to move backward. The pressure from the user's back on the seat back 90 is transmitted to the locking block 50, and then to the bracket 40. This ensures that the seat back 90 can support the user's back, and the seat back 90 is in normal use. Since the stop and pushing part in the locking slot 11 cooperate with the locking block 50 to form a one-way mechanism, the mounting bracket 100 is only allowed to move forward. Figure 3 As shown, when the seat backrest 90 needs to be adjusted forward, the mounting bracket 100 is pushed forward directly. The pushing part in the locking groove 11 pushes the locking block 50 out of the locking groove 11. After the mounting bracket 100 moves to the appropriate position, the locking block 50 is re-engaged into the corresponding locking groove 11 under the elastic stress of the first spring 60. See also Figure 4As shown, if it is necessary to move the seat back 90 backward, the operating end 33 can be operated to move the adjustment button 30 from the first position to the second position. The protrusion 31 on the adjustment button 30 moves forward and pushes the locking block 50, causing the locking block 50 to move away from the mounting bracket 100. When the adjustment button 30 moves to the second position, the locking block 50 moves downward a sufficient distance to disengage from the locking groove 11. At this time, since the protrusion 31 coincides with the locking groove 11 in the front-back direction, it can press down on the locking block 50, preventing the locking block 50 from moving towards the mounting bracket 100. Then, as... Figure 5 As shown, since the locking block 50 is pressed by the protrusion 31, the degree of freedom of the mounting bracket 100 to move backward is no longer limited by the locking block 50. After the mounting bracket 100 is moved backward to the predetermined position, the external force on the operating end 33 is released. The second spring 70 pushes the adjustment button 30 to the first position, so that the protrusion 31 is located on the rear side of the locking groove 11 and is offset from the locking groove 11. The degree of freedom of the locking block 50 to move toward the mounting bracket 100 is no longer limited by the protrusion 31. Under the elastic stress of the first spring 60, the locking block 50 is engaged in the locking groove 11, completing the backward adjustment of the seat back 90.
[0034] In this invention, when the seat back 90 needs to be adjusted forward, simply move the mounting bracket 100 forward relative to the support 40. Once the mounting bracket 100 is moved to the predetermined position, the locking block 50 will engage with the corresponding slot 11 on the mounting bracket 100. When the seat back 90 needs to be adjusted backward, since the adjustment button 30 is designed to move back and forth relative to the mounting bracket 100, and its direction of movement is the same as the direction of movement of the mounting bracket 100 relative to the support 40, the user can simultaneously operate the operating end 33 of the adjustment button 30 and move the mounting bracket 100 with one hand. Thus, the forward and backward movement of the seat back 90 can be operated with one hand, making the adjustment of the seat back 90 simple and convenient.
[0035] In a preferred embodiment, the mounting bracket 100 includes a lower mounting base 10. The aforementioned plurality of locking slots 11 are disposed on the lower surface of the lower mounting base 10. A sliding groove 12 extending back and forth is disposed on the lower mounting base 10. The sliding groove 12 extends from the upper surface of the lower mounting base 10 to the lower surface. The adjustment button 30 is located above the lower mounting base 10. A plurality of protrusions 31 extend downward from the lower surface of the adjustment button 30 and extend into the sliding groove 12, so that the plurality of protrusions 31 are slidably mounted in the sliding groove 12. Thus, the adjustment button 30 is movably mounted on the mounting bracket 100. The aforementioned locking groove 11 includes a limiting wall 112 and an inclined guide wall 111 extending upward from the lower surface of the lower mounting base 10. The limiting wall 112 extends vertically and is perpendicular to the lower surface of the lower mounting base 10. The top end of the inclined guide wall 111 is connected to the top end of the limiting wall 112, and the bottom end is connected to the lower surface of the lower mounting base 10. The inclined guide wall 111 gradually tilts backward from top to bottom. When the mounting bracket 100 is pushed forward relative to the bracket 40, the inclined guide wall 111 can push the locking block 50 downward, and finally allow the locking block 50 to disengage from the locking groove 11. The limiting wall 112 extending vertically can better abut against the front side of the locking block 50. When the seat back 90 is in use, it can better cooperate with the locking block 50, limiting the degree of freedom of the mounting bracket 100 to move backward in the vertical direction perpendicular to the direction of movement of the mounting bracket 100.
[0036] The aforementioned protrusion 31 includes a pressing surface 311 on its front side, a top pressing surface 312 on its bottom side, and a stop surface 313 on its rear side. The pressing surface 311 gradually slopes backward from top to bottom, and the stop surface 313 extends in the vertical direction. The two ends of the top pressing surface 312 are respectively connected to the bottom of the pressing surface 311 and the bottom of the stop surface 313. After the protrusion 31 is placed in the slide groove 12, the top pressing surface 312 is flush with the lower surface of the lower mounting base 10. When the adjustment button 30 is in the first position, the pressing surface 311 on the protrusion 31 is flush with the inclined guide wall 111 on the locking groove 11, and the stop surface 313 on the protrusion 31 is flush with the limiting wall 112 of the locking groove 11 located on the rear side of the protrusion 31.
[0037] The front end of the slide groove 12 forms a front face 121 and the rear end forms a rear face 122. The length of the slide groove 12 limits the maximum travel of the adjustment button 30. When the adjustment button 30 is in the first position, the rear part of the adjustment button 30 abuts against the rear face 122. When the adjustment button 30 is in the first position, the front part of the adjustment button 30 abuts against the front face 121. Specifically, a downward protruding rib 301 is provided on the lower surface of the adjustment button 30. The front end of the protruding rib 301 is a first end face 302 and the rear end is a second end face 303. The length of the protruding rib 301 is less than the length of the slide groove 12. The protruding rib 301 is embedded in the slide groove 12. When the adjustment button 30 is in the first position, the second end face 303 of the protruding rib 301 abuts against the rear face 122. When the adjustment button 30 is in the second position, the first end face 302 of the protruding rib 301 abuts against the front face 121. The aforementioned protrusion 31 may be provided on the rib 301, for example, multiple upwardly recessed notches are provided on the lower surface of the rib 301 to divide the rib 301 into multiple protrusions 31 arranged in the front-back direction.
[0038] The aforementioned sliding groove 12 extends from front to back through multiple locking grooves 11, dividing the locking grooves 11 into two parts located on both sides of the sliding groove 12. The sliding groove 12 can be located at the middle position of the locking groove 11 laterally. The part of the adjustment button 30 located in front of each protrusion 31 forms a relief part 32. The relief part 32 is formed by an upwardly recessed notch on the lower surface of the aforementioned rib 301. The part in front of the first end face 302 of the rib 301 forms the relief part 32 located in front of the foremost protrusion 31. When the adjustment button 30 is in the first position, the locking groove 11 corresponding to the protrusion 31 and the relief part 32 located in front of the protrusion 31 are aligned and together form a groove. This groove allows the top of the locking block 50 to be inserted. When the adjustment button 30 is in the second position, the protrusion 31 and its corresponding locking groove 11 coincide, that is, the relief part 32 and the locking groove 11 are offset in the length direction, so that the locking block 50 cannot be inserted upward into the locking groove 11.
[0039] The aforementioned second spring 70 is disposed between the mounting bracket 100 and the adjustment button 30 to apply a rearward elastic stress to the adjustment button 30. Specifically, the second spring 70 is installed between the lower mounting base 10 and the front end of the adjustment button 30. The second spring 70 can also be replaced by other elastic elements, such as a tension spring or an elastic rubber block. Similarly, the first spring 60 can also be replaced by other elastic elements such as a tension spring or an elastic rubber block. A mounting groove 41 extending vertically is provided on the bracket 40. The locking block 50 is slidably embedded in the mounting groove 41. The first spring 60 is located in the mounting groove 41 to push the locking block 50 upward. The top of the locking block 50 forms a locking end 51. The front side of the locking end 51 forms a vertically extending stop wall 512, and the rear side forms a mating slope 511. The mating slope 511 gradually slopes backward from top to bottom. The mating slope 511 engages with the pressing surface 311 of the protrusion 31 and the inclined guide wall 111 of the locking groove 11. When the pressing surface 311 and the inclined guide wall 111 move forward relative to the locking block 50, the pressing surface 311 and the inclined guide wall 111 can better fit with the mating slope 511 to achieve a reversal, so that the forward movement of the pressing surface 311 and the inclined guide wall 111 is reversed to the downward movement of the mating slope 511.
[0040] The mounting bracket 100 also includes an upper mounting base 20 located above the lower mounting base 10. The upper mounting base 20 and the lower mounting base 10 are detachably coupled and together form a mounting chamber. The adjustment button 30 is located in this mounting chamber, and the rear end of the adjustment button 30 protrudes from the rear of the mounting chamber to form an operating end 33 located outside the mounting bracket 100. The mounting bracket 100 is configured as a detachable coupling structure, which facilitates the assembly of the adjustment button 30, the second spring 70, and the mounting bracket 100. At the same time, the lower mounting base 10 and the upper mounting base 20 each form an outward-facing guide groove on their sides. The bracket 40 is located on the lower mounting base 10. Below 0, two sliders 42 protrude inwards from both sides of the bracket 40. The two sliders 42 protrude inwards from the bracket 40, making the bracket 40 form an upward-opening C-shape. The two sliders 42 are slidably embedded in the two guide grooves, so that the mounting bracket 100 and the bracket 40 slide together. The two sliders 42 cooperate with the lower mounting seat 10 to prevent the bracket 40 from separating from the mounting bracket 100 in the vertical direction. During assembly, the bracket 40 can be inserted from one end of the lower mounting seat 10, so that the two sliders 42 are located on the upper sides of the lower mounting seat 10 respectively. Then, the lower mounting seat 10 and the upper mounting seat 20 are fixed together with screws.
[0041] The seat of this utility model includes the aforementioned backrest front-to-back adjustment mechanism. The other structures of the seat are the same as those in the prior art and will not be described in detail here.
[0042] Finally, it should be noted that the above embodiments are only optional embodiments of this utility model and should not be used to limit the scope of protection of this utility model. Any non-substantial changes and substitutions made by those skilled in the art based on this utility model shall fall within the scope of protection claimed by this utility model.
Claims
1. A backrest fore-and-aft adjustment mechanism, characterized in that, Includes a mounting bracket attached to the backrest, a bracket attached to the seat, a locking mechanism, and adjustment buttons; The mounting bracket and the support slide together so that the mounting bracket can move relative to the support in the front-back direction. The mounting bracket is provided with multiple slots arranged in the front-back direction. The locking block is movably mounted on the bracket, and a first elastic element is provided between the locking block and the bracket. The first elastic element is used to push the locking block toward the mounting bracket so that the locking block can be locked into one of the locking slots. The adjustment button is equipped with an operating end and multiple protrusions arranged in the front-back direction. Each protrusion corresponds to a slot. The adjustment button slides with the mounting bracket to allow the adjustment button to move back and forth between a first position and a second position. When the adjustment button is in the first position, the protrusion is located behind its corresponding slot. When the adjustment button is in the second position, the protrusion and its corresponding slot overlap in the front-back direction. A second elastic element is provided between the adjustment button and the mounting bracket. The second elastic element is used to apply elastic stress to the adjustment button so that the adjustment button always has the tendency to move towards the first position. The operating end is used to drive the adjustment button to move from the first position to the second position. During the process of the adjustment button moving from the first position to the second position, the protrusion moves forward with the adjustment button and pushes the locking block away from the square of the mounting bracket so that the locking block disengages from the locking groove. The inner wall of the locking groove forms a stop and a pusher located behind the stop. The stop is used to cooperate with the locking block to limit the rearward movement of the mounting bracket relative to the locking block when the locking block is engaged in the locking groove. The pusher is used to push the locking block away from the mounting bracket when the mounting bracket moves forward relative to the bracket, so that the locking block is disengaged from the locking groove.
2. The backrest fore-and-aft adjustment mechanism as described in claim 1, characterized in that, The mounting bracket includes a lower mounting base, multiple slots are provided on the lower surface of the lower mounting base, and a sliding groove extending from the upper surface to the lower surface of the lower mounting base is provided on the lower mounting base. An adjustment button is located above the lower mounting base, and a protrusion extends downward from the lower surface of the adjustment button and slides through the sliding groove.
3. The backrest fore-and-aft adjustment mechanism as described in claim 2, characterized in that, The stop part is a limiting wall extending upward from the lower surface of the lower mounting base, and the push part is an inclined guide wall. The top end of the inclined guide wall is connected to the top end of the limiting wall plate, and the bottom end is connected to the lower surface of the lower mounting base. The inclined guide wall gradually slopes backward from top to bottom.
4. The backrest fore-and-aft adjustment mechanism as described in claim 3, characterized in that, The protrusion includes a pressing surface on its front side, a top pressing surface on its bottom side, and a stop surface on its rear side. The pressing surface gradually slopes backward from top to bottom, and the stop surface extends in the vertical direction. The two ends of the top pressing surface are respectively connected to the bottom of the pressing surface and the stop surface and are flush with the lower surface of the lower mounting base. When the adjustment button is in the first position, the pressing surface on the protrusion is flush with the inclined guide wall on the locking groove, and the stop surface on the protrusion is flush with the limiting wall of the locking groove located on the rear side of the protrusion.
5. The backrest fore-and-aft adjustment mechanism as described in claim 2, characterized in that, The front end of the slide forms a front surface and the rear end forms a rear surface. When the adjustment button is in the first position, its rear part abuts against the rear surface. When the adjustment button is in the second position, its front part abuts against the front surface.
6. The backrest fore-and-aft adjustment mechanism as described in claim 2, characterized in that, The slide groove passes through multiple locking slots from front to back, dividing the locking slots into two parts located on both sides of the slide groove; the part of the adjustment button located in front of each protrusion forms a relief part. When the adjustment button is in the first position, the locking slot corresponding to the protrusion and the relief part located in front of the protrusion are aligned and together form a groove.
7. The backrest fore-and-aft adjustment mechanism as described in claim 6, characterized in that, The bracket is provided with a mounting groove extending in the vertical direction. The locking block is slidably embedded in the mounting groove, and the first elastic element is located in the mounting groove. The top of the locking block forms a locking end. The front side of the locking end forms a stop wall extending vertically, and the rear side forms a mating slope. The mating slope gradually slopes backward from top to bottom.
8. The backrest fore-and-aft adjustment mechanism as described in claim 2, characterized in that, The mounting bracket also includes an upper mounting base located above the lower mounting base. The upper mounting base and the lower mounting base are detachably fitted together to form a mounting chamber. The adjustment button is located in the mounting chamber, and the rear end of the adjustment button protrudes from the rear of the mounting chamber to form an operating end located outside the mounting bracket.
9. The backrest fore-and-aft adjustment mechanism as described in claim 8, characterized in that, The lower mounting base and the upper mounting base each form an outward-facing guide groove on both sides. The bracket is located below the lower mounting base, and the bracket has sliders protruding inward on both sides. The two sliders are slidably embedded in the two guide grooves.
10. A seat, characterized in that, Includes the backrest fore-and-aft adjustment mechanism as described in any one of claims 1-9.