Backrest mechanism, seat device, and seat

Abstract

The application relates to a backrest mechanism, a seat device and a seat, belonging to the technical field of seats, which comprises a chair back support and a backrest body; the upper part of the chair back support and the backrest body is provided with an upper connecting rod, one end of the upper connecting rod is rotationally connected to the chair back support, and the other end of the upper connecting rod is rotationally connected to the backrest body; the lower part of the chair back support and the backrest body is provided with a lower connecting rod, one end of the lower connecting rod is rotationally connected to the chair back support, and the other end of the lower connecting rod is rotationally connected to the backrest body; the lower connecting rod has an extension part extending downward, the extension part is rotationally connected with a driving connecting rod used for transmission connection with a seat chassis; the lower connecting rod drives the driving connecting rod to adjust the included angle between the backrest body and the chair back support. The application has the effect of relieving the back rubbing feeling between the backrest body and the back of a user when the user lies backward.

Description

Technical Field

[0001] This application relates to the technical field of seating, and in particular to a backrest mechanism, a seating device, and a seat. Background Technology

[0002] A chair is a basic yet essential tool and piece of furniture. Its core function is to provide support for the human body, enabling us to maintain a comfortable and stable sitting posture. Chairs are commonly seen in offices, study rooms, and other places, meeting people's needs for sitting while working, studying, or resting.

[0003] The seat includes a seat chassis, a backrest bracket rotatably mounted on the seat chassis, a backrest body fixedly mounted on the backrest bracket, a linkage mechanism installed inside the seat chassis and cooperating with the backrest bracket, and a seat support base installed at the bottom of the seat chassis and supported by the ground. When a user sits on the seat, the backrest supports their back, and when the user applies a backward force to the backrest, the backrest bracket rotates backward.

[0004] Regarding the aforementioned technologies, when a user leans against the backrest and reclines, because the backrest is fixedly installed to the chair back support, the backrest moves synchronously with the chair back support when the chair back support rotates, resulting in a noticeable rubbing sensation between the backrest and the user's back. The inventors propose providing a backrest mechanism, seat device, and seat that adjusts the relative position between the backrest and the chair back support to alleviate this rubbing sensation. Utility Model Content

[0005] To alleviate the rubbing sensation between the backrest and the user's back when the user reclines, this application provides a backrest mechanism, a seat device, and a seat.

[0006] Firstly, this application provides a backrest mechanism, which adopts the following technical solution: A backrest mechanism includes a backrest support and a backrest body; an upper connecting rod is provided on the upper part of the backrest support and the backrest body, one end of the upper connecting rod being rotatably connected to the backrest support and the other end of the upper connecting rod being rotatably connected to the backrest body; a lower connecting rod is provided on the lower part of the backrest support and the backrest body, one end of the lower connecting rod being rotatably connected to the backrest support and the other end of the lower connecting rod being rotatably connected to the backrest body; the lower connecting rod has a downwardly extending extension, the extension being rotatably connected to a drive connecting rod for transmission connection with a seat chassis; the backrest body swings relative to the backrest support after being driven by the drive connecting rod.

[0007] By adopting the above technical solution, the upper linkage, backrest support, lower linkage, and backrest body together form a four-bar linkage structure. When the backrest body is subjected to a backward force, the seat chassis will drive the drive linkage to rotate backward, thereby lifting the extension of the lower linkage upward. At this time, the angle between the drive linkage and the lower linkage decreases, while the angle between the backrest support and the backrest body increases accordingly. The backrest body is now tilted downward, and under the coordinated action of the drive linkage, upper linkage, and lower linkage, the backrest body moves downward relative to the backrest support. This allows the user to automatically adjust the relative position of the backrest body and the backrest support while reclining, effectively reducing the feeling of back rubbing.

[0008] Optionally, the lower link includes a connecting section connected to the chair back bracket and the backrest body, and a driving section connected to the driving link; the length of the connecting section is greater than the length of the upper link; the rotation axis of the connecting section and the backrest bracket is lower than the rotation axis of the connecting section and the backrest body; the rotation axis of the upper link and the backrest bracket is lower than the rotation axis of the upper link and the backrest body.

[0009] By adopting the above technical solution, when the backrest body is not under stress, the length of the connecting section is greater than the length of the upper connecting rod, ensuring that the upper and lower connecting rods always remain tilted upwards. When the drive rod pushes the extension of the lower connecting rod upwards, the connecting section of the lower connecting rod rotates downwards, causing the backrest body to move downwards and increasing the angle between the chair back support and the backrest body. This allows for stable and smooth adjustment of the backrest body and enhances comfort during use. Furthermore, the greater length of the connecting section than the upper connecting rod creates a reasonable gap between the backrest body and the chair back support, improving the overall aesthetics.

[0010] Optionally, the lower part of the chair back support is provided with a first mounting seat for rotating one end of the connecting section on the side facing the backrest body, and the lower part of the backrest body is provided with a first mating seat for rotating the other end of the connecting section on the side facing the chair back support.

[0011] By adopting the above technical solution, a first mounting seat and a first mating seat are respectively provided at the lower part of the chair back support and the lower part of the backrest body, providing a stable mounting position for the connecting section of the lower link. This ensures that the lower link can reliably rotate with the chair back support and the backrest body, improving the structural stability of the overall backrest mechanism. At the same time, the reasonable layout of the mounting seats also provides sufficient space for the drive part of the lower link to move during rotation, reducing the probability of interference. Compared to the solution of directly mounting the upper link to the chair back support, in this structure, the drive end of the upper link does not protrude outside the chair back support when it rotates, helping to maintain the simplicity and aesthetics of the overall appearance.

[0012] Optionally, the lower connecting rod has a movable through slot at one end facing the driving connecting rod for rotatable arrangement of the first mounting seat and the driving connecting rod, and there is a movable gap between the bottom of the first mounting seat and the driving connecting rod for swinging of the driving connecting rod.

[0013] By adopting the above technical solution, opening the movable through slot and reserving the movable clearance, the necessary swing space is provided for the drive linkage, ensuring the smooth linkage between the drive linkage and the lower linkage, and also reducing interference from other components during the movement.

[0014] Optionally, the backrest bracket has an arc-shaped movable groove on the side facing the backrest body for the upper connecting rod to rotate; the backrest bracket has a second mounting seat in the arc-shaped movable groove for the upper connecting rod to be rotatably mounted, and the upper part of the backrest body has a second mating seat on the side facing the backrest bracket for the other end of the upper connecting rod to be rotatably mounted.

[0015] By adopting the above technical solution, an arc-shaped movable groove is opened on the chair back support for the upper connecting rod to rotate, providing room for the upper connecting rod to rotate and ensuring smooth rotation. Simultaneously, a second mounting seat is provided within the arc-shaped movable groove, and a second mating seat is provided on the upper part of the backrest body. This allows for the rotatable installation of both ends of the upper connecting rod with the chair back support and the backrest body respectively, enabling a rotatable connection between the backrest body and the chair back support via the upper connecting rod. Furthermore, the angle between the backrest body and the chair back support can be adjusted by driving the lower connecting rod via the drive rod.

[0016] Optionally, the drive link is an arc-shaped link that bends away from the backrest bracket.

[0017] By adopting the above technical solution, the drive linkage of the backrest mechanism uses an arc-shaped linkage that bends away from the backrest support. When it is connected to the seat chassis and the extension of the lower linkage is lifted upwards, its arc-shaped structure can naturally conform to the rotational trajectory of the extension. Furthermore, the curved shape of the linkage better avoids other surrounding structural components, making the overall structural layout more compact and flexible. This allows for smoother adjustment of the angle between the backrest body and the backrest support, reducing interference during the drive process.

[0018] Secondly, this application provides a seating device, which adopts the following technical solution: A seating device includes the aforementioned backrest mechanism and seat chassis, wherein the drive linkage of the backrest mechanism is throttle-connected to the seat chassis.

[0019] By adopting the above technical solution, the drive linkage of the backrest mechanism is connected to the seat chassis, so that the backrest mechanism can cooperate with the seat chassis through the drive linkage to adjust the angle between the backrest body and the backrest support. This allows the backrest body to automatically adjust its relative position with the backrest support when the user is lying down, effectively reducing the back rubbing sensation.

[0020] Optionally, the seat chassis includes a mounting base, a front side plate rotatably mounted on the front end of the mounting base, a top frame rotatably mounted on the top of the front side plate and located on the upper side of the mounting base, a rear seat rotatably mounted on the rear end of the mounting base and fixedly connected to the backrest bracket, a support link rotatably connecting the rear seat and the rear end of the top frame, and an elastic reset mechanism for driving the seat chassis to reset; the support link has a first toothed portion that meshes with the rear end of the mounting base; the lower end of the drive link is rotatably connected to the support link.

[0021] By adopting the above technical solution, the mounting base, front side panel, top frame, support linkage, and rear seat together constitute a five-bar linkage mechanism, realizing the transmission connection between the backrest mechanism and the seat chassis. When the user leans back, the force is transmitted to the rear seat through the backrest bracket, driving the five-bar linkage mechanism to move: the rear seat is driven to rotate backward, the rear seat drives the top frame to move backward as a whole and rotate slightly, and then the front side panel is driven to rotate backward by the top frame. At the same time, a coordinated movement also occurs in the four-bar linkage system composed of the drive linkage, upper linkage, and lower linkage, driving the backrest body to move downward relative to the backrest bracket. The combined action of these two mechanisms, the backward tilting of the seat chassis and the downward sinking of the backrest body, together achieve adaptive adjustment of the backrest angle, significantly improving the comfort of reclining and effectively reducing the back rubbing sensation. Moreover, the elastic reset mechanism can drive the backrest mechanism and seat chassis to return to their initial state after the user no longer applies force to the backrest body. The first convex tooth that engages with the rear end of the support linkage and the mounting base can adjust the rotation angle of the backrest mechanism relative to the seat assembly.

[0022] Optionally, the rotatable connection between the support link and the rear tailstock has a rear pivot; the rotatable connection between the mounting base and the front side plate has a front pivot; the elastic reset mechanism includes a reset bracket rotatably mounted on the rear pivot and an elastic tension spring rotatably connecting the reset bracket and the front pivot.

[0023] By adopting the above technical solution, the rear panel, reset bracket, elastic spring, and mounting base together constitute a five-bar linkage mechanism. After the user no longer applies force to the backrest body, the elastic spring returns to its initial state and pulls the reset bracket, thereby causing the front panel, top frame, support link, and rear seat to return to their initial positions. At the same time, the upper link, lower link, and backrest body also return to their initial states.

[0024] Thirdly, this application provides a seat, which adopts the following technical solution: A seat includes the seat assembly described above and a support mechanism mounted on the bottom of the seat assembly for supporting the ground.

[0025] By adopting the above technical solution, the backrest mechanism can adjust the angle between the backrest body and the chair back support through the drive linkage to achieve the adjustment of the height of the backrest body; the seat chassis can achieve the rotation and reset functions through the cooperation of various components and the elastic reset mechanism; the support seat is installed at the bottom of the seat device to provide support for the seat, so that the overall structure of the seat is stable and has functions such as backrest adjustment and reset.

[0026] In summary, this application includes at least one of the following beneficial technical effects: 1. A backrest mechanism, wherein an upper link, a backrest support, a lower link, and a backrest body together form a four-bar linkage structure. When the backrest body rotates backward, the seat chassis drives the drive link to rotate backward, thereby lifting the extension of the lower link upward, and the position of the backrest body is adjusted through the four-bar linkage structure. 2. A seat device, wherein the drive linkage of the backrest mechanism is connected to the seat chassis via a transmission, so that the backrest mechanism can automatically adjust the relative position of the backrest body and the backrest support through the cooperation of the drive linkage and the seat chassis, and the elastic reset mechanism can drive the backrest mechanism and the seat chassis to return to the initial state. 3. A type of chair that allows the user to automatically adjust the relative position of the backrest body and the backrest support while reclining, effectively reducing the feeling of back rubbing. Attached Figure Description

[0027] Figure 1 This is a structural schematic diagram of a seat in Example 3.

[0028] Figure 2 This is a schematic diagram of a backrest mechanism in Embodiment 1.

[0029] Figure 3 This is a schematic diagram of the cooperative structure of the lower connecting rod, the backrest body, the chair back support, and the drive connecting rod in Embodiment 1.

[0030] Figure 4 This is a schematic diagram of the cooperation structure between the upper connecting rod and the chair back support in Embodiment 1.

[0031] Figure 5 This is a schematic diagram of the cooperation structure between the upper connecting rod and the backrest body in Embodiment 1.

[0032] Figure 6 This is a structural schematic diagram of a seat device in Embodiment 2.

[0033] Figure 7 This is a structural schematic diagram of the seat chassis in Example 2.

[0034] Figure 8 This is a schematic diagram of the cooperative structure of the top frame, support rod and rear tailstock in Embodiment 2.

[0035] Figure 9 This is a schematic diagram of the cooperation structure between the support rod and the mounting base in Embodiment 2.

[0036] Figure 10 This is a schematic diagram of the elastic reset mechanism in Embodiment 2.

[0037] Figure 11 This is a schematic diagram of the tension adjustment mechanism in Example 2.

[0038] Figure 12 This is a schematic diagram of the mating structure of the first bevel gear and the second bevel gear in Example 2.

[0039] Figure 13 This is a schematic diagram of the mating structure of the base plate, the mounting plate, and the connecting spring in Embodiment 2.

[0040] Explanation of reference numerals in the attached drawings: 1. Backrest mechanism; 11. Backrest support; 111. Armrest placement; 1111. Support platform; 1112. Armrest arm; 112. First mounting seat; 113. Arc-shaped movable groove; 114. Second mounting seat; 12. Backrest body; 121. Support surface; 122. Headrest; 1221. Support arc surface; 123. First mating seat; 124. Second mating seat; 13. Support arc rod; 14. Lower connecting rod; 141. Extension; 142. Connecting section 143. Drive section; 144. Movable through slot; 1441. Movable clearance; 15. Drive linkage; 16. Upper linkage; 2. Seat chassis; 21. Mounting base; 211. Second convex tooth; 212. Mounting slot; 213. Rotary bearing; 214. Limiting component; 2141. Limiting plate; 2142. Limiting seat; 2143. Limiting through hole; 215. Mounting protrusion; 22. Front side plate; 23. Top frame; 231. Mating base plate; 2311. First hook; 232. Mounting top plate; 2321. Second hook; 233. Connecting spring; 2331. First hook; 2332. Second hook; 24. Rear tailstock; 241. Rear tail plate; 242. Connecting plate; 25. Supporting rod; 251. First toothed part; 26. Elastic reset mechanism; 261. Reset bracket; 262. Elastic spring; 2621. Elastic spring; 2622. First connecting piece; 2623. Second connecting piece; 263. Connecting shaft; 27. Upward rotation 1. Shaft; 28. Rear rotating shaft; 29. ​​Front rotating shaft; 3. Tension adjustment mechanism; 31. Lifting drive assembly; 311. Rotating shaft; 312. First bevel gear; 313. Second bevel gear; 314. Drive component; 32. Connecting rod assembly; 321. Longitudinal connecting rod; 322. Bending connecting rod; 323. Adjusting block; 3231. Threaded through hole; 3232. Threaded part; 4. Support mechanism; 41. Support rod; 42. Support seat; 421. Support arm; 422. Rolling pulley. Detailed Implementation

[0041] The following is in conjunction with the appendix Figure 1-13 This application will be described in further detail.

[0042] This application discloses a backrest mechanism.

[0043] Example 1 Reference Figure 1 The backrest mechanism 1 includes a backrest support 11 and a backrest body 12. The backrest support 11 is generally L-shaped, and its vertical part constitutes the main support structure. The backrest body 12 is located on the front side of the backrest support 11, and its outline is designed to conform to the outline of the back when a person is seated. The front of the backrest body 12 has a support surface 121 for supporting the back of the human body.

[0044] Reference Figure 1The backrest body 12 has a head support 122 mounted on its top for supporting the human head, and a support arc rod 13 for supporting the head support 122. The head support 122 has a neck-supporting arc surface 1221 that conforms to the contour of the human neck. The arc-shaped protrusion of the support arc rod 13 faces away from the head support 122, which enhances the support strength for the head support 122. In this embodiment, one end of the support arc rod 13 is integrally formed on the side of the backrest body 12 facing the backrest bracket 11, and the other end is integrally formed on the side of the head support component facing the backrest body 12.

[0045] Reference Figure 1 The chair back support 11 is further provided with armrests 111 on both sides of the backrest body 12 for placing human arms. The armrests 111 include a support platform 1111 for arm support and armrests 1112 installed on the chair back support 11 for supporting the support platform 1111. In this embodiment, the armrests 1112 are installed on the chair back support 11 by bolts, and the support platform 1111 is locked to the armrests 1112 by bolts.

[0046] Reference Figure 1 and Figure 2 A lower connecting rod 14 is provided at the lower part of the backrest support 11 and the backrest body 12. One end of the lower connecting rod 14 is rotatably connected to the backrest support 11, and the other end of the lower connecting rod 14 is rotatably connected to the backrest body 12. The lower connecting rod 14 also has a downwardly extending extension 141, which is rotatably connected to a drive connecting rod 15 for transmission connection with the seat chassis 2. The lower connecting rod 14 includes a connecting section 142 connected to the backrest support 11 and the backrest body 12, and a drive section 143 connected to the drive connecting rod 15. The drive connecting rod 15 is rotatably connected to the lower connecting rod 14 by a hinge.

[0047] Reference Figure 2 The lower part of the chair back support 11, facing the backrest body 12, is provided with a first mounting seat 112 for rotatably mounting one end of the lower connecting rod 14. The lower part of the backrest body 12, facing the chair back support 11, is provided with a first mating seat 123 for rotatably mounting the other end of the lower connecting rod 14. In this embodiment, the first mounting seat 112 is integrally disposed on the chair back support 11, and the first mating seat 123 is integrally disposed on the backrest body 12. The lower connecting rod 14 is rotatably connected to the first mounting seat 112 by a hinge, and the lower connecting rod 14 is rotatably connected to the first mating seat 123 by a hinge.

[0048] Reference Figure 2To ensure that the drive section 143 of the lower connecting rod 14 has sufficient room to move during rotation and to reduce the probability of interference from surrounding components during rotation, in this embodiment, the first mounting base 112 is set perpendicular to the chair back bracket 11 and its length is not less than five centimeters.

[0049] Reference Figure 2 The drive link 15 is an arc-shaped link that bends away from the backrest support 11. When it is in transmission cooperation with the seat chassis 2, the structure of the drive link 15 can naturally fit with the rotational trajectory of the extension 141 of the lower link 14 when it pushes the extension 141 of the lower link 14 upward, avoiding other structural components around it and reducing interference during the drive process.

[0050] Reference Figure 2 and Figure 3 The lower connecting rod 14 also has a movable through slot 144 at the end facing the drive connecting rod 15 for rotatable arrangement of the first mounting base 112 and the drive connecting rod 15. There is a movable gap 1441 between the bottom of the first mounting base 112 and the drive connecting rod 15 for swinging of the drive connecting rod 15. The movable gap 1441 provides a certain swing space for the drive connecting rod 15, which can reduce interference from other components during the movement.

[0051] Reference Figure 4 and Figure 5 An upper connecting rod 16 is provided on the upper part of the chair back support 11 and the backrest body 12. One end of the upper connecting rod 16 is rotatably connected to the chair back support 11, and the other end is rotatably connected to the backrest body 12. The chair back support 11 has an arc-shaped movable groove 113 on the side facing the backrest body 12 for the upper connecting rod 16 to rotate. A second mounting seat 114 for rotatably mounting one end of the upper connecting rod 16 is provided in the arc-shaped movable groove 113 on the upper part of the chair back support 11, and a second mating seat 124 for rotatably mounting the other end of the upper connecting rod 16 is provided on the upper part of the backrest body 12 facing the chair back support 11. When the upper connecting rod 16 rotates, the arc-shaped movable groove 113 provides movement space for the upper connecting rod 16, reducing the probability of interference from surrounding components during rotation and making the rotation of the upper connecting rod 16 smoother.

[0052] Reference Figure 1 and Figure 2The upper connecting rod 16, the backrest support 11, the lower connecting rod 14, and the backrest body 12 are sequentially hinged to form a four-bar structure. The length of the connecting segment 142 of the lower connecting rod 14 is greater than the length of the upper connecting rod 16. The rotation axis of the connecting segment 142 and the backrest support is lower than the rotation axis of the connecting segment 142 and the backrest body 12; the rotation axis of the upper connecting rod 16 and the backrest support is lower than the rotation axis of the upper connecting rod 16 and the backrest body 12. This structure forms an irregular trapezoid. When the backrest body 12 is not under stress, the upper connecting rod 16 and the lower connecting rod 14 always remain tilted upwards, making the bottom height of the backrest body 12 higher than the bottom height of the backrest support 11, and forming a certain angle between the backrest body 12 and the backrest support 11. Furthermore, the length of the connecting segment 142 is greater than that of the upper connecting rod 16, allowing for a reasonable gap between the backrest body 12 and the backrest support 11, improving the overall aesthetics.

[0053] Reference Figure 2 When the backrest body 12 is subjected to a backward force, the seat chassis 2 will drive the drive linkage 15 to rotate backward, thereby lifting the extension 141 of the lower linkage 14 upward. At the same time, the connecting section 142 will rotate downward, thereby causing the backrest body 12 to move downward relative to the backrest support 11, and the angle between the backrest support 11 and the backrest body 12 will also increase, so that the backrest body 12 is in a downward tilted state, which can ensure that the backrest body 12 is in close contact with the user's back when the user lies down, reducing the back rubbing sensation.

[0054] Combination Figures 1 to 5 The implementation principle of Embodiment 1 is as follows: the upper connecting rod 16, the backrest support 11, the lower connecting rod 14, and the backrest body 12 together form a four-bar linkage structure. When the backrest body 12 is subjected to a rearward force, the seat chassis 2 will drive the drive connecting rod 15 to rotate. During the rotation, the drive connecting rod 15 will push the extension 141 of the lower connecting rod 14 upward, while the connecting section 142 will rotate downward, thereby causing the backrest body 12 to swing downward relative to the backrest support 11. The angle between the backrest support 11 and the backrest body 12 will also increase, making the backrest body 12 tilt downward. This ensures that the backrest body 12 is in close contact with the user's back when the user is lying down, reducing the feeling of back rubbing.

[0055] Example 2 Reference Figures 1 to 13 The difference between this embodiment and embodiment 1 is that a seat chassis 2 is added that is connected to the backrest mechanism 1 via a transmission.

[0056] Reference Figure 6 and Figure 7The seat assembly includes the aforementioned backrest mechanism 1 and seat chassis 2, with the drive linkage 15 of the backrest mechanism 1 being hygienically connected to the seat chassis 2. The seat chassis 2 includes a mounting base 21, a front side plate 22 rotatably mounted to the front end of the mounting base 21, a top frame 23 rotatably mounted to the top of the front side plate 22 and located on the upper side of the mounting base 21, a rear seat 24 rotatably mounted to the rear end of the mounting base 21 and fixedly connected to the backrest bracket 11, a support linkage 25 rotatably connecting the rear seat 24 and the rear end of the top frame 23, and an elastic reset mechanism 26 for driving the seat chassis 2 to reset. The mounting base 21 is fixedly mounted to the seat support 42. In this embodiment, the mounting base 21, front side plate 22, top frame 23, support linkage 25, and rear seat 24 are sequentially rotatably connected by hinges.

[0057] Reference Figure 6 and Figure 7 The rear seat 24 includes a rear plate 241 for fixing the backrest bracket 11 and a connecting plate 242 for connecting the mounting base 21 and the support rod 25. In this embodiment, the backrest bracket 11 is fixedly installed on the top of the rear plate 241 by bolts.

[0058] Reference Figure 6 and Figure 8 The rotatable connection between the support link 25 and the top frame 23 has an upper rotating shaft 27, and the rotatable connection between the support link 25 and the connecting plate 242 has a rear rotating shaft 28. The end of the drive link 15 away from the first mounting base 112 is rotatably mounted on the upper rotating shaft 27.

[0059] Reference Figure 6 and Figure 7 The mounting base 21, front side panel 22, top frame 23, support link 25, and rear seat 24 together form a five-bar linkage. When the user leans back against the backrest body 12, the force is transmitted to the rear seat 24 through the backrest bracket, driving the front side panel 22 to rotate backward, which in turn causes the top frame 23 to move backward and rotate slightly. At the same time, the backrest mechanism 1 also moves in coordination, driving the lower link 14 and upper link 16 to rotate downward through the drive link 15, causing the backrest body 12 to move downward relative to the backrest support 11. When the user no longer applies force to the backrest body 12, the backrest mechanism 1 and seat chassis 2 can be driven back to their initial state.

[0060] Reference Figure 6 and Figure 9The support link 25 has a first tooth 251 on the side facing away from the backrest assembly that engages with the rear end of the mounting base 21. The mounting base 21 has a second tooth 211 that engages with the first tooth 251. When the backrest body 12 is subjected to a rearward force, the backrest mechanism 1 will rotate rearward. The engagement of the first tooth 251 and the second tooth 211 can adjust the rotation angle of the backrest mechanism 1 relative to the seat assembly. When the backrest mechanism is not subjected to force, the engagement of the first tooth 251 and the second tooth 211 ensures that the support link 25 will not rotate.

[0061] Reference Figure 7 and Figure 10 The mounting base 21 and the front side plate 22 have a front rotating shaft 29 at their rotatable connection. The elastic reset mechanism 26 includes a reset bracket 261 rotatably mounted on the rear rotating shaft 28 and an elastic tension spring 262 rotatably connecting the reset bracket 261 and the front rotating shaft 29. In this embodiment, there are two elastic tension springs 262, and the reset bracket 261 is bent toward the mounting base 21. A connecting shaft 263 is provided at the rotatable connection between the reset bracket 261 and the two elastic tension springs 262. The elastic tension spring 262 includes an elastic tension spring 2621, a first connecting piece 2622 connected to one end of the elastic tension spring 2621, and a second connecting piece 2623 connected to the other end of the elastic tension spring 2621. The first connecting piece 2622 is rotatably connected to the connecting shaft 263; the second connecting piece 2623 is rotatably connected to the front rotating shaft 29.

[0062] Reference Figure 11 and Figure 12 The seat chassis 2 also includes a tension adjustment mechanism 3 for adjusting the tensile stress of the elastic spring 262. The tension adjustment mechanism 3 includes a lifting drive assembly 31 mounted on the mounting base 21 and a connecting rod assembly 32 cooperating with the lifting drive assembly 31. The lifting drive assembly 31 includes a rotating shaft 311 rotatably mounted on the inner side of the mounting base 21, a first bevel gear 312 fixed to the outer peripheral side wall of the rotating shaft 311, a second bevel gear 313 meshing with the first bevel gear 312, and a drive member 314 for driving the second bevel gear 313. The mounting base 21 has a mounting groove 212 for mounting the rotating shaft 311, and a rotating bearing 213 sleeved on the rotating shaft 311 is also provided in the mounting groove 212. The inner side of the mounting base 21 has a mounting protrusion 215 for mounting the second bevel gear 313, and the drive member 314 is mounted on the outer side wall of the mounting base 21.

[0063] Reference Figures 11 to 12The connecting rod assembly 32 includes a longitudinal connecting rod 321 rotatably mounted on the connecting shaft 263, a bent connecting rod 322 rotatably connecting the front shaft 29 and the longitudinal connecting rod 321, and an adjusting block 323 mounted on the bent connecting rod 322. The bent connecting rod 322 is bent toward the mounting base 21. The adjusting block 323 has a threaded through hole 3231 extending through its upper and lower surfaces. The top of the rotating shaft 311 has a threaded portion 3232 that mates with the threaded through hole 3231. When the user starts the drive unit 314, the second bevel gear 313 drives the first bevel gear 312 to mesh and transmit power, thereby driving the rotating shaft 311 to rotate. Through the threaded engagement between the threaded portion 3232 and the adjusting block 323, the rotational motion is converted into height adjustment of the connecting rod, thereby controlling the tensile stress of the elastic spring 262. In this embodiment, there are two longitudinal connecting rods 321, which are symmetrically arranged on both sides of the lifting drive assembly 31, and the two ends of the adjusting block 323 are rotatably connected to the two longitudinal connecting rods 321.

[0064] Reference Figure 11 and Figure 12 To limit the displacement of the rotating shaft 311 during rotation, a limiting member 214 is installed on the mounting base 21. The limiting member 214 includes a limiting plate 2141 and a limiting seat 2142 disposed on the mounting base 21 for mounting the limiting plate 2141. The limiting plate 2141 has a limiting through hole 2143 extending through its upper and lower surfaces for the rotating shaft 311 to pass through. In this embodiment, the limiting plate 2141 is bolted to the limiting seat 2142.

[0065] Reference Figure 13 The top frame 23 includes a mating base plate 231 and a mounting top plate 232 mounted on top of the mating base plate 231 for mounting the seat cushion. A connecting spring 233 is provided between the bottom of the mounting top plate 232 and the mating base plate 231. The end of the connecting spring 233 is provided with a first hook 2331 and a second hook 2332. The mating base plate 231 is provided with a first hook portion 2311 for the first hook 2331 to be hooked, and the mounting top plate 232 is provided with a second hook portion 2321 for the second hook 2332 to be hooked.

[0066] Reference Figure 7 and Figure 13 When the backrest mechanism tilts backward, the rear seat 24 is driven to rotate backward, which in turn causes the mating base plate 231 to move backward as a whole and rotate slightly. The mounting top plate 232 will also move backward slightly with the mating base plate 231 under the action of the connecting spring 233. When the backrest mechanism 1 and the seat chassis 2 return to their initial state, the connecting spring 233 will drive the mating base plate 231 to return to its initial state.

[0067] Combination Figures 1 to 13The implementation principle of Embodiment 2 is as follows: The mounting base 21, front side plate 22, top frame 23, support link 25, and rear seat 24 together constitute a five-bar linkage. When the user leans back against the backrest body 12, the force is transmitted to the rear seat 24 through the backrest support. The rear seat 24 is driven to rotate backward, which in turn drives the top frame 23 to move backward and rotate slightly. Consequently, the front side plate 22 is driven to rotate backward by the top frame 23. At the same time, a coordinated movement also occurs in the four-bar linkage system composed of drive link 15, upper link 16, and lower link 14. Drive link 15 drives the lower link 14 and upper link 16 to rotate downward, causing the backrest body 12 to swing downward relative to the backrest support 11. The angle between the backrest support 11 and the backrest body 12 also increases, causing the backrest body 12 to tilt downward, ensuring that the backrest body 12 is in close contact with the user's back during the user's reclining process, reducing the feeling of back rubbing. When the user does not apply force to the backrest body 12, the elastic reset mechanism 26 can drive the backrest mechanism 1 and the seat chassis 2 back to their initial state. The first tooth 251 of the support link 25, which engages with the rear end of the mounting base 21, can adjust the rotation angle of the backrest mechanism 1 relative to the seat chassis 2.

[0068] Example 3 Reference Figure 1 The difference between this embodiment and embodiment 2 is that a support mechanism 4 is added, which is installed at the bottom of the seat device and is used to support the ground.

[0069] Reference Figure 1 The support mechanism 4 includes a support rod 41 mounted on the mounting base 21 and a support seat 42 mounted on the lower part of the support rod 41 for supporting the ground. The support seat 42 has multiple support arms 421, which are arranged radially outward from the support rod 41. Rolling pulleys 422 are mounted on the ends of the support arms 421 away from the support rod 41 for rolling contact with the ground. In this embodiment, there are five support arms 421, and the rolling pulleys 422 mounted on their ends are omnidirectional wheels, capable of sliding in different directions.

[0070] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A backrest mechanism, characterized in that, The chair includes a backrest support (11) and a backrest body (12); an upper connecting rod (16) is provided on the upper part of the backrest support (11) and the backrest body (12), one end of the upper connecting rod (16) is rotatably connected to the backrest support (11), and the other end of the upper connecting rod (16) is rotatably connected to the backrest body (12); a lower connecting rod (14) is provided on the lower part of the backrest support (11) and the backrest body (12), the lower connecting rod (14)... One end of the lower connecting rod (14) is rotatably connected to the backrest support (11), and the other end of the lower connecting rod (14) is rotatably connected to the backrest body (12); the lower connecting rod (14) has a downwardly extending extension (141), and the extension (141) is rotatably connected to a drive connecting rod (15) for transmission connection with the seat chassis (2); the backrest body (12) swings relative to the backrest support (11) after being driven by the drive connecting rod (15).

2. The backrest mechanism according to claim 1, characterized in that, The lower link (14) includes a connecting section (142) connected to the backrest bracket (11) and the backrest body (12) and a driving section (143) connected to the driving link (15); the length of the connecting section (142) is greater than the length of the upper link (16); the rotation axis of the connecting section (142) and the backrest bracket is lower than the rotation axis of the connecting section (142) and the backrest body (12); the rotation axis of the upper link (16) and the backrest bracket is lower than the rotation axis of the upper link (16) and the backrest body (12).

3. A backrest mechanism according to claim 2, characterized in that, The lower part of the chair back support (11) facing the backrest body (12) is provided with a first mounting seat (112) for rotatably mounting one end of the connecting section (142), and the lower part of the backrest body (12) facing the chair back support (11) is provided with a first mating seat (123) for rotatably mounting the other end of the connecting section (142).

4. A backrest mechanism according to claim 3, characterized in that, The lower connecting rod (14) has a movable through groove (144) at one end facing the driving connecting rod (15) for the first mounting base (112) and the driving connecting rod (15) to rotate. There is a movable gap (1441) between the bottom of the first mounting base (112) and the driving connecting rod (15) for the driving connecting rod (15) to swing.

5. A backrest mechanism according to claim 1, characterized in that, The backrest bracket (11) has an arc-shaped movable groove (113) on the side facing the backrest body (12) for the upper connecting rod (16) to rotate; the backrest bracket (11) has a second mounting seat (114) in the arc-shaped movable groove (113) for one end of the upper connecting rod (16) to be rotatably installed; the upper part of the backrest body (12) has a second mating seat (124) on the side facing the backrest bracket (11) for the other end of the upper connecting rod (16) to be rotatably installed.

6. A backrest mechanism according to claim 1, characterized in that, The drive link (15) is an arc-shaped link that bends away from the backrest support (11).

7. A seating device, characterized in that, Includes the backrest mechanism (1) and seat chassis (2) as described in any one of claims 1-6, wherein the drive linkage (15) of the backrest mechanism (1) is tractively connected to the seat chassis (2).

8. A seating device according to claim 7, characterized in that, The seat chassis (2) includes a mounting base (21), a front side plate (22) rotatably mounted on the front end of the mounting base (21), a top frame (23) rotatably mounted on the top of the front side plate (22) and located on the upper side of the mounting base (21), a rear seat (24) rotatably mounted on the rear end of the mounting base (21) and fixedly connected to the backrest bracket (11), a support link (25) rotatably connecting the rear seat (24) and the rear end of the top frame (23), and an elastic reset mechanism (26) for driving the seat chassis (2) to reset; the support link (25) has a first tooth (251) that meshes with the rear end of the mounting base (21); the lower end of the drive link (15) is rotatably connected to the support link (25).

9. A seating device according to claim 8, characterized in that, The supporting link (25) and the rear tailstock (24) have a rear pivot (28) at the rotatable connection; the mounting base (21) and the front side plate (22) have a front pivot (29) at the rotatable connection; the elastic reset mechanism (26) includes a reset bracket (261) rotatably mounted on the rear pivot (28) and an elastic tension spring (262) rotatably connecting the reset bracket (261) and the front pivot (29).

10. A type of seat, characterized in that, Includes the seating device as described in any one of claims 7-9 and a support mechanism (4) installed at the bottom of the seating device for supporting the ground.

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