Adjustable backrest for seat and seat

Abstract

The utility model discloses an adjustable backrest for a seat and the seat, and belongs to the technical field of seats, the adjustable backrest comprises a backrest body, a connecting frame, a fixed seat and a self-locking mechanism, the backrest body is mounted on the connecting frame, and the connecting frame and the fixed seat are in sliding fit along the height direction of the seat and have a first stroke and a second stroke; the self-locking mechanism comprises a plurality of meshing teeth formed on the connecting frame; the clamping jaw is arranged on the fixed seat and can swing and move relative to the fixed seat; the elastic piece applies pressure to the clamping jaw in a manner that the clamping jaw tends to be meshed with the meshing teeth; the locking part is formed on the fixed seat; the first pushing and pressing part and the second pushing and pressing part are both formed on the connecting frame; the first pushing and pressing part is used for pushing and pressing the clamping jaw at the terminal point of the first stroke and driving the clamping jaw to move to be clamped with the locking part; the second pushing and pressing part is used for pushing and pressing the clamping jaw at the end point of the second stroke and driving the clamping jaw to move to be separated from the locking part. The position of the backrest body in the height direction relative to the chair back can be conveniently adjusted.

Description

Technical Field

[0001] The utility model relates to the technical field of seats, in particular to an adjustable backrest for a seat and the seat. Background Art

[0002] In order to accommodate users of different heights and body shapes, the seats in the related art are equipped with a liftable backrest on the chair back, and the user can adjust the backrest to a suitable height according to his or her needs. The solutions for adjusting the backrest in the related art generally adopt an electric adjustment solution or a manual adjustment solution. The electric adjustment solution requires the setting of a drive motor and a control program, which is relatively expensive, and requires a special installation position for the drive motor, which increases the overall volume of the seat. The manual adjustment solution often sets a manual locking mechanism. When the backrest position needs to be adjusted, the user needs to unlock the manual locking mechanism with one hand and adjust the backrest position with the other hand. After the backrest position is adjusted, the manual locking mechanism is locked again. This adjustment solution is inconvenient to operate. Utility Model Content

[0003] The purpose of the utility model is to provide an adjustable backrest for a chair and a chair, which can conveniently adjust the position of the backrest body relative to the chair back in the height direction according to the user's needs.

[0004] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0005] An adjustable backrest for a seat, comprising a backrest body, a connecting frame, a fixing seat, and a self-locking mechanism, wherein the backrest body is mounted on the connecting frame, the fixing seat is used to be fixedly mounted to the seat back, the connecting frame and the fixing seat are slidably engaged along the height direction of the seat and have a first stroke and a second stroke relative to the fixing seat, the first stroke being opposite to the second stroke;

[0006] The self-locking mechanism comprises:

[0007] a plurality of teeth formed on the connecting frame and continuously distributed along the height direction of the seat;

[0008] a claw, which is disposed on the fixed base and is configured to swing and move relative to the fixed base, wherein the claw can engage and disengage relative to the gear by swinging;

[0009] an elastic member that applies pressure to the claw so as to cause the claw to engage with the teeth;

[0010] a locking portion formed on the fixing seat; and

[0011] A first pushing portion and a second pushing portion, both of which are formed on the connecting frame;

[0012] The first pushing portion is used to push the claw at the end point of the first stroke and drive the claw to move to engage with the locking portion, so that the claw is fixed relative to the fixing seat and remains separated from the teeth in the second stroke;

[0013] The second pushing portion is used to push the claw at the end point of the second stroke and drive the claw to move away from the locking portion, so that the claw is movably arranged relative to the fixing seat in the first stroke and can engage with and disengage from the gear.

[0014] Preferably, the first stroke is a stroke in which the connecting frame drives the backrest body to rise relative to the chair back, and the second stroke is a stroke in which the connecting frame drives the backrest body to fall relative to the chair back.

[0015] Preferably, the connecting frame is formed with a long hole extending along the height direction of the seat, the gear is formed on the inner wall of one side of the long hole, and a groove is formed on the inner wall of the other side of the long hole, the bottom wall of the groove forms the first pushing portion, and the top wall of the groove forms the second pushing portion; the fixing seat is formed with a mounting cavity, the claw and the elastic member are both arranged in the mounting cavity, the claw has a clamping portion, a pressure-bearing portion and an engaging portion, the clamping portion is used to cooperate with the locking portion, and the locking portion is a clamping groove formed on the inner wall of the mounting cavity; the pressure-bearing portion is used to cooperate with the first pushing portion and the second pushing portion, and the engaging portion is used to cooperate with the gear, and the mounting cavity has a first opening and a second opening, the pressure-bearing portion can extend from the first opening into the groove, and the engaging portion can extend from the second opening to engage with the gear.

[0016] Preferably, the fixing seat includes a base plate located on one side of the connecting frame, a cover plate located on the other side of the connecting frame, and a protrusion extending into the long hole, the protrusion is formed on the base plate, the cover plate is fixedly installed on the protrusion, and the installation cavity is formed between the protrusion and the cover plate.

[0017] Preferably, the inner wall of the mounting cavity is provided with a long groove, and the clamping claw is fixedly provided with a rotating shaft extending into the long groove, and the length of the long groove is larger than the diameter of the rotating shaft, so that the rotating shaft can be rotatably and movably arranged in the long groove.

[0018] Preferably, the portion of the base plate outside the protrusion cooperates with the cover plate and the protrusion to form a slide groove, and the connecting frame has a sliding section extending along the height direction of the seat, and the sliding section is slidably arranged in the slide groove.

[0019] Preferably, two first limiting flanges are formed on the connecting frame on the side where the base plate is located, and two second limiting flanges are formed on the connecting frame on the side where the cover plate is located, and the first limiting flange and the second limiting flange both extend along the height direction of the seat; the slide formed between the two first limiting flanges slides in conjunction with the base plate, and the slide formed between the two second limiting flanges slides in conjunction with the cover plate.

[0020] Preferably, the top wall and the bottom wall of the long hole in the height direction of the seat cooperate with the top end and the bottom end of the protrusion respectively to limit the distance of the first stroke and the second stroke.

[0021] In addition, to achieve the above purpose, the present invention also adopts the following technical solutions:

[0022] A seat, comprising a chair back, further comprising an adjustable backrest as described in any one of the above technical solutions, wherein the adjustable backrest is fixedly mounted on the chair back via a fixing seat.

[0023] Preferably, the seat further comprises a lumbar support, which is mounted on the connecting frame and located below the backrest body.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] The self-locking mechanism allows the claw to be movable relative to the fixed seat and engage and disengage with the teeth in the first stroke, and to be fixed relative to the fixed seat and disengaged from the teeth in the second stroke. This allows the user to slide the connecting frame (and the backrest body) relative to the fixed seat (and the seat back) simply by pushing or pulling the backrest body or the connecting frame. Once the backrest body has slid to the target position, the claw engages with the teeth to maintain stability relative to the seat back, simplifying the height adjustment of the backrest body. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A schematic structural diagram of an adjustable backrest for a seat provided in an embodiment of the present application;

[0027] Figure 2 This is an exploded view of the adjustable backrest;

[0028] Figure 3 It is a structural diagram of the main shell in the connecting frame;

[0029] Figure 4 It is a structural diagram of the fixed seat;

[0030] Figure 5 This is an exploded view of the fixed seat and the claw;

[0031] Figure 6This is a schematic diagram of the assembly of the main housing and the fixing seat;

[0032] Figure 7 A front view of the connecting frame (without the cover), the fixing base (without the cover plate), and the self-locking mechanism with the claws engaged with the teeth at a certain position (a schematic diagram of the connecting frame in the first stroke);

[0033] Figure 8 A front view of the connecting frame (without the cover), the fixing base (without the cover plate), and the self-locking mechanism when the claws and the teeth are separated (a schematic diagram of the connecting frame in the first stroke);

[0034] Figure 9 It is a front view of the connecting frame (without the cover), the fixing base (without the cover plate) and the self-locking mechanism when the claws are engaged with the locking part;

[0035] Figure 10 Schematic diagram of the connecting frame (without the cover), the fixing base (without the cover plate), and the self-locking mechanism during the second stroke of the connecting frame;

[0036] Figure 11 It is a front view of the connecting frame (without the cover), the fixing base (without the cover plate) and the self-locking mechanism when the claw is separated from the locking part;

[0037] Figure 12 The figure is a structural diagram of a chair back equipped with a lumbar support and an adjustable backrest provided in this embodiment.

[0038] Among them, 1. backrest body; 2. connecting frame; 20. main shell; 21. cover body; 22. long hole; 23. meshing tooth; 24. groove; 240. first pushing part; 241. second pushing part; 25. first limiting flange; 26. second limiting flange; 3. fixing seat; 30. bottom plate; 31. protrusion; 310. first long groove; 32. cover plate; 320. second long groove; 33. installation cavity; 330. locking part; 331. first opening; 332. second opening; 34. slide groove; 4. claw; 40. clamping part; 41. pressure part; 42. meshing part; 43. first rotating shaft; 44. second rotating shaft; 5. elastic member; 6. fastening screw; 7. lumbar support; 8. chair back. DETAILED DESCRIPTION

[0039] Below, the present invention is further described in conjunction with the accompanying drawings and specific embodiments. It should be noted that, under the premise of no conflict, the various embodiments described below or the various technical features can be arbitrarily combined to form a new embodiment. Unless otherwise specified, the materials and equipment used in this embodiment can be purchased from the market. Examples of the embodiments are shown in the accompanying drawings, in which the same or similar numbers throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and cannot be understood as limiting this application.

[0040] In the description of this application, it should be understood that the terms "upper," "lower," "front," "back," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like, indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended only to facilitate the description of this application and simplify the description. They do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limiting this application. In the description of this application, "plurality" means two or more, unless otherwise specifically specified.

[0041] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "connected," "connected," and "connected" should be understood in a broad sense. For example, they may refer to a fixed connection, a connection through an intermediary medium, internal communication between two components, or an interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0042] This embodiment provides an adjustable backrest for a chair, such as Figure 1 、 Figure 2 and Figure 12 As shown in , the adjustable backrest comprises a backrest body 1, a connecting frame 2, a fixed seat 3, and a self-locking mechanism. The backrest body 1 is mounted on the connecting frame 2, and the fixed seat 3 is fixedly mounted to the seat back 8. The connecting frame 2 and the fixed seat 3 slide together along the height direction of the seat, and have a first stroke and a second stroke relative to the fixed seat 3, with the first stroke and the second stroke being opposite. Therefore, when the user needs to adjust the height of the backrest body 1, they slide the connecting frame 2 relative to the fixed seat 3, which drives the backrest body 1 up and down relative to the seat back 8.

[0043] Combine Figure 3 、 Figure 4 and Figure 5As shown in , the self-locking mechanism in this embodiment is used to automatically lock the connecting frame 2 relative to the fixed seat 3 when the backrest body 1 slides to the target position, so as to maintain the stability of the backrest body 1 relative to the chair back 8. Specifically, the self-locking mechanism in this embodiment includes a tooth 23 formed on the connecting frame 2, a claw 4 provided on the fixed seat 3, a locking portion 330 formed on the fixed seat 3, an elastic member 5 applying pressure to the claw 4, and a first pushing portion 240 and a second pushing portion 241 formed on the connecting frame 2. Among them, there are multiple teeth 23, and the multiple teeth 23 are continuously distributed along the height direction of the seat. The claw 4 is configured to be able to swing and move relative to the fixed seat 3, and the claw 4 can engage and disengage relative to the tooth 23 by swinging. The elastic member 5 applies pressure to the claw 4 so that the claw 4 has a tendency to engage with the tooth 23. The first pushing portion 240 is used to push the claw 4 at the end point of the first stroke and drive the claw 4 to move to engage with the locking portion 330, so that the claw 4 is fixed relative to the fixed seat 3 in the second stroke and remains separated from the tooth 23; the second pushing portion 241 is used to push the claw 4 at the end point of the second stroke and drive the claw 4 to move to separate from the locking portion 330, so that the claw 4 is movably set relative to the fixed seat 3 in the first stroke and can engage with and separate from the tooth 23.

[0044] The self-locking mechanism allows the claw 4 to be movable relative to the fixed seat 3 and to engage and disengage with the teeth 23 in the first stroke, and to be fixed relative to the fixed seat 3 and to remain disengaged from the teeth 23 in the second stroke. In this way, the user only needs to push or pull the backrest body 1 or the connecting frame 2 to slide the connecting frame 2 (and the backrest body 1) relative to the fixed seat 3 (and the seat back 8). After the backrest body 1 slides to the target position, the claw 4 engages with the teeth 23 and remains stable relative to the seat back 8, simplifying the height adjustment operation of the backrest body 1.

[0045] It should be noted that, in this embodiment, by designing the engagement direction of the claw 4 and the teeth 23, as well as the vertical positions of various components in the self-locking mechanism, the first stroke is the stroke in which the connecting frame 2 drives the backrest body 1 upward relative to the seat back 8, and the second stroke is the stroke in which the connecting frame 2 drives the backrest body 1 downward relative to the seat back 8. In other words, if the user wishes to adjust the backrest body 1 to a higher position, the user can directly push the backrest body 1 or the connecting frame 2, causing the connecting frame 2 to slide through the first stroke until the backrest body 1 reaches the target position, at which point the claw 4 engages with the teeth 23 at the corresponding position. If the user wishes to adjust the backrest body 1 to a lower position, the user must first push the backrest body 1 or the connecting frame 2 upward, sliding through the first stroke until the end of the first stroke, when the first pressing portion 240 applies pressure to the claw 4, causing the claw 4 to engage with the locking portion 330. Then, the backrest body 1 or the connecting frame 2 is pushed downward to slide in the second stroke until the end of the second stroke, when the second pushing portion 241 presses the claw 4 so that the claw 4 is separated from the locking portion 330. Finally, the backrest body 1 or the connecting frame 2 is pushed upward to slide in the first stroke until the backrest body 1 slides to the target position.

[0046] It is easy to understand that by changing the engagement direction of the claw 4 and the teeth 23, and at the same time changing the upper and lower position design of each structure in the self-locking mechanism, the first stroke can be the stroke in which the connecting frame 2 drives the backrest body 1 to descend relative to the chair back 8, and correspondingly, the second stroke can be the stroke in which the connecting frame 2 drives the backrest body 1 to rise relative to the chair back 8.

[0047] like Figure 2 and Figure 3 As shown in , in order to facilitate the assembly operation of the connecting frame 2 and the backrest body 1, the connecting frame 2 in this embodiment includes a main shell 20 and a cover 21 fixedly provided on the main shell 20. The backrest body 1 is fixedly mounted on the cover 21 by screws, and the cover 21 is snapped onto the main shell 20 and locked and fixed with the main shell 20 by screws. It is easy to understand that in other optional embodiments, the connecting frame 2 can also be an integrally molded structure. In this embodiment, a long hole 22 extending along the height direction of the seat is formed on the main shell 20 of the connecting frame 2, a tooth 23 is formed on the inner wall of one side of the long hole 22, and a groove 24 is formed on the inner wall of the other side of the long hole 22, the bottom wall of the groove 24 forms a first pushing portion 240, and the top wall of the groove 24 forms a second pushing portion 241.

[0048] Combine Figure 4 and Figure 5As shown in , the fixing seat 3 in this embodiment is formed with a mounting cavity 33, the claw 4 and the elastic member 5 are both arranged in the mounting cavity 33, the claw 4 has a clamping portion 40, a pressure portion 41 and an engaging portion 42, the clamping portion 40 is used to cooperate with the locking portion 330, and the locking portion 330 is a clamping groove formed on the inner wall of the mounting cavity 33; the pressure portion 41 is used to cooperate with the first pushing portion 240 and the second pushing portion 241, and the engaging portion 42 is used to cooperate with the gear 23, and the mounting cavity 33 has a first opening 331 and a second opening 332, the pressure portion 41 can extend from the first opening 331 into the groove 24, and the engaging portion 42 can extend from the second opening 332 to engage with the gear 23. Specifically, the elastic member 5 in this embodiment is a metal spring. A mounting groove matching the shape of the metal spring is formed on the inner wall of the mounting cavity 33, and the metal spring is disposed in the mounting groove. One side of the metal spring abuts against the inner wall of the mounting cavity 33, and the other side abuts against the claw 4, thereby constantly applying pressure to the claw 4 toward the side where the tooth 23 is located. It will be readily understood that in other optional embodiments, the elastic member 5 may also be an elastic body such as a spring.

[0049] It should be noted here that the cooperation between the meshing portion 42 and the tooth 23 is both engagement and separation. A tooth groove is formed between two adjacent teeth 23, and the meshing portion 42 is adapted to the shape of the tooth groove. When the meshing portion 42 is inserted into the tooth groove, the meshing portion 42 and the tooth 23 are engaged; when the meshing portion 42 is disengaged from the tooth groove, the meshing portion 42 and the tooth 23 are separated.

[0050] To facilitate assembly, the fixing base 3 in this embodiment includes a bottom plate 30 located on one side of the connecting frame 2, a cover plate 32 located on the other side of the connecting frame 2, and a protrusion 31 extending into the long hole 22. The protrusion 31 is formed on the bottom plate 30, and the cover plate 32 is fixedly installed on the protrusion 31. The installation cavity 33 is formed between the protrusion 31 and the cover plate 32. Therefore, the design of the connecting frame 2 in this embodiment including the main shell 20 and the cover body 21 can also form a cavity between the main shell 20 and the cover body 21, so that the cover plate 32 in the fixing base 3 can be placed in the cavity, which is more beautiful. Figure 2 and Figure 6 As shown in FIG, during assembly, the base plate 30 is placed on one side of the main housing 20, and the protrusion 31 formed on the base plate 30 is extended from one side of the main housing 20 to the other side into the long hole 22. Then, the cover plate 32 placed on the other side of the main housing 20 is fastened to the protrusion 31 using two fastening screws 6. Afterwards, the cover body 21 with the backrest body 1 mounted thereon is fastened to the main housing 20 and secured.

[0051] As mentioned above, the connecting frame 2 and the fixing seat 3 are slidably matched. In this embodiment, a limiting structure is provided between the two to improve the sliding stability of the connecting frame 2. Figure 2 and Figure 4As shown in FIG, in this embodiment, the portion of the bottom plate 30 outside the protrusion 31 cooperates with the cover plate 32 and the protrusion 31 to form a slide groove 34, and the connecting frame 2 has a sliding section extending along the height direction of the seat, and the sliding section is slidably arranged in the slide groove 34. In addition, as shown in FIG. Figure 1 As shown, in this embodiment, two first limiting flanges 25 are formed on the side of the connecting frame 2 where the bottom plate 30 is located. Figure 6 As shown, two second limiting flanges 26 are formed on the connecting frame 2 on the side where the cover plate 32 is located. Both the first limiting flange 25 and the second limiting flange 26 extend along the height of the seat. The slide formed between the two first limiting flanges 25 slidably engages with the base plate 30, while the slide formed between the two second limiting flanges 26 slidably engages with the cover plate 32.

[0052] Combine Figure 2 and Figure 5 As shown in , in this embodiment, a long slot is provided on the inner wall of the mounting cavity 33, and a rotating shaft is fixedly mounted on the claw 4, extending into the long slot. The length of the long slot is greater than the diameter of the rotating shaft, so that the rotating shaft can be rotatably and movably mounted within the long slot. Specifically, a first long slot 310 is provided on the protrusion 31, and a first rotating shaft 43 is provided on the side of the claw 4 facing the protrusion 31. A second long slot 320 is provided on the cover plate 32, and a second rotating shaft 44 is provided on the side of the claw 4 facing the protrusion 31. The first rotating shaft 43 is inserted into the first long slot 310, and the second rotating shaft 44 is inserted into the second long slot 320.

[0053] Combine Figures 7 to 11 As shown in FIG, the operation process of adjusting the height of the backrest body 1 is described as follows:

[0054] like Figure 7 As shown in the figure, the "up" direction indicated by the arrow is the direction in which the connecting frame 2 performs the first stroke, and the "down" direction indicated by the arrow is the direction in which the connecting frame 2 performs the second stroke. Figure 7 The state shown in FIG is the state of the connecting frame 2 (and the backrest body 1 installed on the connecting frame 2) at the initial position. At this time, the claws 4 are engaged with the teeth 23, and the connecting frame 2 remains stable relative to the fixing seat 3.

[0055] If the user needs to adjust the backrest body 1 upward, the user directly pushes the connecting frame 2 (or the backrest body 1) upward. Under the external pressure of the user, the teeth 23 on the connecting frame 2 press upward on the claw 4. Due to the guiding slope between the two, the force of the teeth 23 pressing upward on the claw 4 will partially act obliquely on the claw 4. This oblique force will overcome the elastic force of the elastic member 5 and make the claw 4 swing relative to the fixed seat 3, thereby separating the meshing portion 42 on the claw 4 from the teeth 23. At this time, the positional relationship between the claw 4 and the connecting frame 2 is as follows: Figure 8 As shown in .

[0056] The user can continue to push the connecting frame 2 to make the engaging portion 42 on the claw 4 engage and disengage with the multiple teeth 23 until the backrest body 1 moves to the target position. At this time, the engaging portion 42 on the claw 4 engages with the corresponding teeth 23, so that the connecting frame 2 and the fixing seat 3 remain stable, completing the height adjustment of the backrest body 1.

[0057] If the user needs to adjust the backrest body 1 downward, the user needs to push the connecting frame 2 (or the backrest body 1) upward to complete the first stroke. Figure 9 As shown in FIG, at the end of the first stroke, the first pushing portion 240 on the connecting frame 2 pushes the pressure portion 41 on the claw 4 upward from the bottom, driving the claw 4 to move upward relative to the fixing seat 3 until the engaging portion 40 on the claw 4 engages with the locking portion 330 in the mounting cavity 33. Under the combined action of the elastic member 5 and the locking portion 330, the claw 4 remains stationary relative to the fixing seat 3. Figure 10 As shown in , the user pushes the connecting frame 2 downward to complete the entire second stroke, during which the claw 4 remains stable relative to the fixing seat 3 and remains separated from the teeth 23 until the end of the second stroke. Figure 11 As shown in FIG, at the end of the second stroke, the second pushing portion 241 on the connecting frame 2 pushes the pressed portion 41 on the claw 4 downward from the top, driving the claw 4 to move downward relative to the fixing base 3, so that the engaging portion 40 on the claw 4 disengages from the locking portion 330. Afterwards, under the action of the elastic member 5, the claw 4 can swing relative to the fixing base 3, so that the claw 4 can engage and disengage with the tooth 23 through the engaging portion 42. Finally, the user only needs to Figure 11 The connecting frame 2 shown in FIG is located at the lowest point and the aforementioned upward adjustment operation is performed to drive the backrest body 1 to slide to the target position.

[0058] like Figure 9 and Figure 11 As shown in FIG, in this embodiment, the size and relative position of the long hole 22 and the protrusion 31 along the height direction of the seat are designed. The top and bottom walls of the long hole 22 along the height direction of the seat cooperate with the top and bottom ends of the protrusion 31 respectively, thereby limiting the distance of the first stroke and the second stroke. That is, when the connecting frame 2 is at the highest position ( Figure 9 As shown in FIG), the first pushing portion 240 on the connecting frame 2 abuts against the pressed portion 41 on the claw 4, and at the same time, the bottom wall of the long hole 22 abuts against the bottom end of the protrusion 31. Accordingly, when the connecting frame 2 is at the lowest position ( Figure 11 As shown in FIG, the second pressing portion 241 on the connecting frame 2 abuts against the pressed portion 41 on the claw 4, and at the same time, the top wall of the long hole 22 abuts against the top end of the protrusion 31. This structural design makes it easier for the user to sense whether the connecting frame 2 has slid into place during operation, making it easier to determine whether the first and second strokes have been completed.

[0059] like Figure 12 As shown in , the adjustable backrest provided in this embodiment can be used for a seat, which includes a backrest 8. The adjustable backrest is fixed to the backrest 8 via a fixing base 3. In some optional embodiments, the seat may further include a lumbar support 7. For users of different body shapes, when the height of the backrest body 1 needs to be adjusted, the height of the lumbar support 7 often also needs to be adjusted accordingly. Therefore, the lumbar support 7 can be installed on the connecting frame 2 and positioned below the backrest body 1. In this way, the height of the lumbar support 7 can be adjusted synchronously with the backrest body 1.

[0060] Finally, it should be noted that the above-mentioned implementation methods are only optional embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and replacements made by technicians in this field on the basis of the present invention fall within the scope of protection required by the present invention.

Claims

1. An adjustable backrest for a seat, comprising a backrest body, characterized in that: The adjustable backrest further comprises a connecting frame, a fixing seat and a self-locking mechanism, the backrest body being mounted on the connecting frame, the fixing seat being used for fixing to the backrest of the seat, the connecting frame and the fixing seat being slidably engaged along the height direction of the seat and having a first stroke and a second stroke relative to the fixing seat, the first stroke being opposite to the second stroke; The self-locking mechanism comprises: a plurality of teeth formed on the connecting frame and continuously distributed along the height direction of the seat; a claw, which is disposed on the fixed base and is configured to swing and move relative to the fixed base, wherein the claw can engage and disengage relative to the gear by swinging; an elastic member that applies pressure to the claw so as to cause the claw to engage with the teeth; a locking portion formed on the fixing seat; and A first pushing portion and a second pushing portion, both of which are formed on the connecting frame; The first pushing portion is used to push the claw at the end point of the first stroke and drive the claw to move to engage with the locking portion, so that the claw is fixed relative to the fixing seat and remains separated from the teeth in the second stroke; The second pushing portion is used to push the claw at the end point of the second stroke and drive the claw to move away from the locking portion, so that the claw is movably arranged relative to the fixing seat in the first stroke and can engage with and disengage from the gear.

2. The adjustable backrest according to claim 1, characterized in that The first stroke is a stroke in which the connecting frame drives the backrest body to rise relative to the chair back, and the second stroke is a stroke in which the connecting frame drives the backrest body to fall relative to the chair back.

3. The adjustable backrest according to claim 1 or 2, characterized in that: The connecting frame is formed with a long hole extending in the height direction of the seat, the teeth are formed on the inner wall of one side of the long hole, a groove is formed on the inner wall of the other side of the long hole, the bottom wall of the groove forms the first pushing portion, and the top wall of the groove forms the second pushing portion; The fixing seat is formed with a mounting cavity, the claw and the elastic member are both arranged in the mounting cavity, the claw has a clamping portion, a pressure-receiving portion and an engaging portion, the clamping portion is used to cooperate with the locking portion, and the locking portion is a clamping groove formed on the inner wall of the mounting cavity; The pressure-bearing portion is used to cooperate with the first pushing portion and the second pushing portion, and the engaging portion is used to cooperate with the meshing teeth. The mounting cavity has a first opening and a second opening. The pressure-bearing portion can extend from the first opening into the groove, and the engaging portion can extend from the second opening to engage with the meshing teeth.

4. The adjustable backrest according to claim 3, characterized in that The fixing seat includes a base plate located on one side of the connecting frame, a cover plate located on the other side of the connecting frame, and a protrusion extending into the long hole. The protrusion is formed on the base plate, the cover plate is fixedly installed on the protrusion, and the installation cavity is formed between the protrusion and the cover plate.

5. The adjustable backrest according to claim 4, characterized in that The inner wall of the mounting cavity is provided with a long groove, and the clamping claw is fixedly provided with a rotating shaft extending into the long groove. The length of the long groove is larger than the diameter of the rotating shaft, so that the rotating shaft can be rotatably and movably arranged in the long groove.

6. The adjustable backrest according to claim 4, characterized in that The portion of the bottom plate outside the protrusion cooperates with the cover plate and the protrusion to form a slide groove. The connecting frame has a sliding section extending along the height direction of the seat, and the sliding section is slidably arranged in the slide groove.

7. The adjustable backrest according to claim 4, characterized in that Two first limiting flanges are formed on the connecting frame on the side where the bottom plate is located, and two second limiting flanges are formed on the connecting frame on the side where the cover plate is located, and the first limiting flanges and the second limiting flanges both extend along the height direction of the seat; The slideway formed between the two first position-limiting flanges is in sliding cooperation with the bottom plate, and the slideway formed between the two second position-limiting flanges is in sliding cooperation with the cover plate.

8. The adjustable backrest according to claim 4, wherein: The top wall and the bottom wall of the long hole along the height direction of the seat respectively cooperate with the top end and the bottom end of the protrusion to limit the distance of the first stroke and the second stroke.

9. A seat, including a seat back, characterized in that: The seat further comprises an adjustable backrest according to any one of claims 1 to 8, wherein the adjustable backrest is fixedly mounted to the chair back via a fixing seat.

10. The seat according to claim 9, wherein The seat further comprises a lumbar support which is mounted on the connecting frame and is located below the backrest body.

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