Seat back and ergonomic seat

Abstract

The invention provides a seat backrest. The seat backrest comprises a main waist rest with a connecting part; the auxiliary waist rest is provided with a transverse waist hole; the backrest plate is provided with a vertical kidney-shaped hole, and the connecting part can penetrate through the transverse kidney-shaped hole and the vertical kidney-shaped hole to connect the main waist rest, the auxiliary waist rest and the backrest plate together; the fastener and the connecting part have a first mechanical coupling state and a second mechanical coupling state, and when the fastener and the connecting part are in the first mechanical coupling state, the connecting part can move in the transverse kidney-shaped hole so that the auxiliary waist rest can adjust the position in the transverse direction relative to the main waist rest, and the connecting part can also move in the vertical kidney-shaped hole so that the auxiliary waist rest can adjust the position in the transverse direction relative to the main waist rest. The position of the main waist rest can be adjusted in the vertical direction relative to the backrest plate; when the main waist rest and the auxiliary waist rest are in the second mechanical coupling state, the main waist rest, the auxiliary waist rest and the backrest plate are mutually locked. The connecting part of the seat backrest provided by the invention not only realizes a connecting function, but also realizes a sliding function, so that the structure of the seat backrest is simpler, and the manufacturing cost is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of seat manufacturing, in particular to a multi-position adjustable seat back and an ergonomic seat adopting the same. BACKGROUND

[0002] Currently, some ergonomic seats have a main backrest plate, side backrest plates arranged on the main backrest plate, and a waist rest. The waist rest can move vertically along the main backrest plate and is kept at different heights. The side backrest plates are arranged on both sides of the main backrest plate and can move laterally to adjust the distance to the main backrest plate to clasp the waist of a seated person. For example, the applicant previously proposed an application for an ergonomic seat with the application number 202310357932.0, which has a vertical sliding rail embedded in the main backrest plate and a secondary backrest plate that can move along the sliding rail. The waist rest is connected to the secondary backrest plate to adjust the height of the waist rest. The side backrest plate is connected to the secondary backrest plate by a first connecting rod, which has a first end fixedly connected to the secondary backrest plate and a second end embedded in the side backrest plate. A plurality of grooves are formed on the second end, and at least one protrusion is formed on the inner wall of the side backrest plate. The protrusion can be located in any of the grooves to adjust the distance between the side backrest plate and the main backrest plate. However, the connection and transmission relationship between the main backrest plate, the side backrest plate, and the waist rest is relatively complex, and it is necessary to provide a seat back with a simpler structure. SUMMARY

[0003] In view of the problems in the background art, the present application provides a seat back, comprising:

[0004] a main waist rest having a connecting portion;

[0005] a secondary waist rest having a transverse waist hole;

[0006] a backrest plate having a vertical waist hole, the connecting portion being capable of passing through the transverse waist hole and the vertical waist hole to connect the main waist rest, the secondary waist rest, and the backrest plate together; and

[0007] a fastener having a first mechanical coupling state and a second mechanical coupling state with the connecting portion and being configured to:

[0008] when both are in the first mechanical coupling state, the connecting portion is capable of moving in the transverse waist hole to allow the secondary waist rest to adjust the position in the transverse direction relative to the main waist rest, and the connecting portion is also capable of moving in the vertical waist hole to allow the main waist rest to adjust the position in the vertical direction relative to the backrest plate;

[0009] when both are in the second mechanical coupling state, the main waist rest, the secondary waist rest, and the backrest plate are locked with each other.

[0010] In some embodiments of the present application, the length of the connecting portion in the first direction is equal to the width of the vertical waist hole, and the length of the connecting portion in the second direction is equal to the width of the horizontal waist hole.

[0011] In some embodiments of the present application, the main waist rest is connected with the connecting portion by an elastic element, and the main waist rest can be kept in close contact with the waist of a seated person under the action of the elastic element.

[0012] In some embodiments of the present application, the auxiliary waist rest comprises: support bodies arranged on both sides of the main waist rest; connecting frames connected to each of the support bodies, the connecting frames being formed with the horizontal waist hole, one of the two connecting frames being formed with a pair of parallel guide rails, the extension direction of the guide rails being the same as the extension direction of the horizontal waist hole, so that the other connecting frame can move transversely relative to the former under the guidance of the guide rails.

[0013] In some embodiments of the present application, the connecting frame comprises: a first connecting rod partially embedded in the support body; a second connecting rod formed with the horizontal waist hole, the exposed end of the first connecting rod and one of the second connecting rods being formed with a plug-in block, and the other being formed with a plug-in slot matched with the plug-in block.

[0014] In some embodiments of the present application, the plug-in block and the plug-in slot are combined to form an included angle between the first connecting rod and the second connecting rod.

[0015] In some embodiments of the present application, the seat backrest comprises: a support beam fixedly embedded in the backrest plate, the support beam also being formed with a vertical waist hole, and the connecting portion being capable of passing through the horizontal waist hole and the vertical waist hole to connect the main waist rest, the auxiliary waist rest, the backrest plate and the support beam together.

[0016] In some embodiments of the present application, the backrest plate is formed with a protruding portion, the two sides of the protruding portion being formed with recessed portions, the support beam being embedded in the protruding portion, and the second connecting rod being capable of moving transversely in the recessed portions.

[0017] In some embodiments of the present application, the seat backrest comprises: an inclined shoulder rest arranged on the backrest plate, the upper part of the shoulder rest being more protruding than the lower part.

[0018] Another aspect of the present application provides an ergonomic chair comprising any one of the seat backrests as described above.

[0019] The extension range of the vertical waist hole of the seat back is the vertical adjustable movement range of the main waist rest relative to the back plate. The extension range of the transverse waist hole is the transverse adjustable movement range of the auxiliary waist rest relative to the main waist rest. That is, the connecting part realizes both the connecting function and the sliding function, so that the structure of the seat back is simpler, and the manufacturing cost is reduced.

[0020] When people with different body shapes sit, the connecting part and the fastener are first in the first mechanical coupling state, then the vertical height of the main waist rest is adjusted, so that it can press against the waist of the sitter in front, preventing the sitter from sitting for a long time with the waist suspended, and the transverse extension amount of the auxiliary waist rest is adjusted, so that it can wrap the waist of the sitter from both sides, preventing the sitter from unconsciously tilting the body when sitting for a long time, causing the lumbar spine to rotate, and having a certain correcting effect on the lumbar spine. Finally, the connecting part and the fastener are in the second mechanical coupling state, and the main waist rest, the auxiliary waist rest and the back plate are locked with each other. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 The structure schematic diagram of the ergonomic seat provided by an embodiment of the present application (the main waist rest is in the high position, and the auxiliary waist rest is contracted);

[0022] Figure 2 The structure schematic diagram of the ergonomic seat shown in Figure 1 The structure schematic diagram of the ergonomic seat shown in

[0023] Figure 3 The structure schematic diagram of the ergonomic seat shown in Figure 1 The structure schematic diagram of the ergonomic seat shown in

[0024] Figure 4 The back side schematic diagram of the ergonomic seat shown in Figure 1

[0025] Figure 5 The internal structure schematic diagram of the back plate of the ergonomic seat shown in Figure 1

[0026] The assembly schematic diagram of the main waist rest, the auxiliary waist rest and the support beam; Figure 6

[0027] The assembly schematic diagram of the main waist rest, the auxiliary waist rest and the support beam (remove the support body); Figure 7

[0028] The assembly schematic diagram of the two second connecting rods shown in Figure 8 Figure 7 The assembly schematic diagram of the two second connecting rods shown in

[0029] Figure 9 Figure 1 ​​​Structure diagram of the main waist rest (first direction) shown in FIG. 1;

[0030] Figure 10 For Figure 1 Structure diagram of the main waist rest (second direction) shown in FIG. 2;

[0031] Figure 11 For Figure 10 Assembly diagram of the main waist rest and the fastener shown in FIG. 3.

[0032] Explanation of reference numerals:

[0033] Main waist rest 10; connecting part 10a; screw thread 10b; elastic element 10c;

[0034] Sub waist rest 20; transverse waist hole 20a; support body 21; connecting frame 22; first connecting rod 22a; second connecting rod 22b; guide rail 23; plug-in block 24; plug-in slot 25;

[0035] Backrest plate 30; vertical waist hole 30a; front panel 30b; back panel 30c; support beam 30d; protruding part 31; recessed part 32;

[0036] Fastener 40;

[0037] Shoulder rest 50. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in combination with the drawings and specific embodiments. Although the exemplary embodiments are disclosed in the drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided so as to make the present application more thoroughly understood and to enable the complete conception of the present application to be conveyed to those skilled in the art.

[0039] As Figures 1 to 8As shown, one embodiment of the present application provides a seat backrest, which comprises a main lumbar support 10 having a connecting portion 10a, a sub-lumbar support 20 having a transverse lumbar hole 20a, a backrest plate 30 having a vertical lumbar hole 30a, and a fastener 40. The connecting portion 10a is capable of passing through the transverse lumbar hole 20a and the vertical lumbar hole 30a to connect the main lumbar support 10, the sub-lumbar support 20 and the backrest plate 30 together. The fastener 40 has a first mechanical coupling state and a second mechanical coupling state with the connecting portion 10a, and is configured to allow the connecting portion 10a to move in the transverse lumbar hole 20a to adjust the position of the sub-lumbar support 20 relative to the main lumbar support 10 and to move in the vertical lumbar hole 30a to adjust the position of the main lumbar support 10 relative to the backrest plate 30 when the two are in the first mechanical coupling state, and to lock the main lumbar support 10, the sub-lumbar support 20 and the backrest plate 30 relative to each other when the two are in the second mechanical coupling state.

[0040] In the present embodiment, the backrest plate 30 is disassembled into a front panel 30b and a back panel 30c which are fixedly connected (e.g. by screws, bolts, gluing, etc.) to each other, and the vertical lumbar hole 30a is formed in the front panel 30b and the back panel 30c respectively.

[0041] In other embodiments, the backrest plate 30 can have only one of the front panel 30b or the back panel 30c, which is capable of supporting the back of a seated person, and the vertical lumbar hole 30a is formed in the front panel 30b or the back panel 30c.

[0042] In the present embodiment, the support beam 30d is fixedly (e.g. by screws, bolts, gluing, etc.) embedded in the backrest plate 30, and the vertical lumbar hole 30a is also formed in the support beam 30d to allow the connecting portion 10a to pass through the transverse lumbar hole 20a and the vertical lumbar hole 30a to connect the main lumbar support 10, the sub-lumbar support 20 and the backrest plate 30 (including the support beam 30d) together. The support beam 30d and the backrest plate 30 can have various embedding manners. For example, the support beam 30d is wrapped by the front panel 30b and the back panel 30c and is not exposed. For another example, in the case of having only one of the front panel 30b or the back panel 30c, the middle part of the front panel 30b or the back panel 30c can have a bent accommodating area, and the support beam 30d is embedded in the bent accommodating area. The positions of the vertical lumbar holes 30a formed in the front panel 30b and / or the back panel 30c and the support beam 30d are aligned.

[0043] In the present embodiment, a thread 10b is formed on the end of the connecting portion 10a, and the fastener 40 is a nut that matches the thread 10b of the connecting portion 10a. For example, a common nut or a petal-shaped hand nut. The first mechanical coupling state refers to rotating the fastener 40 counterclockwise / clockwise, loosening the main lumbar support 10 and the secondary lumbar support 20 relative to the backrest plate 30 (and the support beam 30d), so that the components can be independently adjusted in position. The second mechanical coupling state refers to rotating the fastener 40 in the opposite direction, pressing the secondary lumbar support 20 against the backrest plate 30 (and the support beam 30d) using the close coupling of the fastener 40 and the connecting portion 10a, so that the main lumbar support 10, the secondary lumbar support 20, and the backrest plate 30 are locked to each other.

[0044] In other embodiments, the fastener 40 can also be mechanically coupled with the connecting portion 10a by means of insertion, etc. For example, at least two slots or holes can be provided along the length of the connecting portion 10a, when the fastener 40 is arranged in one of the slots or holes, the main lumbar support 10 and the secondary lumbar support 20 are loosened relative to the backrest plate 30 (and the support beam 30d), so that the components can be independently adjusted in position. When the fastener 40 is arranged in the other slot or hole, the secondary lumbar support 20 is pressed against the backrest plate 30 (and the support beam 30d) using the close coupling of the fastener 40 and the connecting portion 10a, so that the main lumbar support 10, the secondary lumbar support 20, and the backrest plate 30 are locked to each other. For another example, the connecting portion 10a can be a straight rod with one end thick and one end thin, and the fastener 40 is an annular elastic piece that can be sleeved on the connecting portion 10a. When the fastener 40 is pulled to move on the connecting portion 10a to the thin end, the main lumbar support 10 and the secondary lumbar support 20 are loosened relative to the backrest plate 30 (and the support beam 30d), so that the components can be independently adjusted in position. When the fastener 40 is pulled to move on the connecting portion 10a to the thick end, the secondary lumbar support 20 is pressed against the backrest plate 30 (and the support beam 30d) using the close coupling of the fastener 40 and the connecting portion 10a, so that the main lumbar support 10, the secondary lumbar support 20, and the backrest plate 30 are locked to each other.

[0045] Those skilled in the art should understand that the extension range of the vertical lumbar hole 30a is the vertical adjustable movement range of the main lumbar support 10 relative to the backrest plate 30. The extension range of the transverse lumbar hole 20a is the transverse adjustable movement range of the secondary lumbar support 20 relative to the main lumbar support 10. That is, the connecting portion 10a not only realizes the connection function, but also realizes the sliding function, so that the structure of the seat backrest is simpler and the manufacturing cost is reduced.

[0046] When people of different body types are seated, the connecting portion 10a and the fastener 40 are first in the first mechanical coupling state, then the vertical height of the main waist rest 10 is adjusted so that it can push against the waist of the seated person forward, preventing the seated person from sitting for a long time with the waist suspended or collapsed backward, and the lateral extension of the auxiliary waist rest 20 is adjusted so that it can wrap the waist of the seated person from both sides, preventing the seated person from unconsciously tilting the body when sitting for a long time, causing the lumbar spine to rotate and bend sideways, and having a certain correcting and supporting effect on the lumbar spine. Finally, the connecting portion 10a and the fastener 40 are in the second mechanical coupling state, and the main waist rest 10, the auxiliary waist rest 20 and the backrest plate 30 are locked with each other.

[0047] Referring to Figure 9 Further, the length L1 of the connecting portion 10a in the first direction is equal to the width of the lateral waist hole 20a, and the length L2 of the connecting portion 10a in the second direction is equal to the width of the vertical waist hole 30a.

[0048] Those skilled in the art should understand that "equal" should be understood as equal or substantially equal, so that the connecting portion 10a is in a small gap fit with the lateral waist hole 20a and the vertical waist hole 30a, and the connecting portion can slide in the lateral waist hole 20a and the vertical waist hole 30a without rotating, that is, the main waist rest 10 can only adjust the height in the up and down directions along a straight line with respect to the backrest plate 30 (and the support beam 30d), and cannot rotate with respect to the backrest plate 30 (and the support beam 30d), and the auxiliary waist rest 20 can only adjust the extension range in the left and right directions along a straight line with respect to the backrest plate 30 (and the support beam 30d), and cannot rotate with respect to the backrest plate 30 (and the support beam 30d), thereby ensuring the stability of movement.

[0049] Referring to Figures 10 to 11 Further, the main waist rest 10 is connected to the connecting portion 10a by the elastic element 10c, and the main waist rest 10 can be kept in close contact with the waist of the seated person under the action of the elastic element 10c.

[0050] In this embodiment, the elastic element 10c can be a spring with a relatively large elastic modulus, one end of which is connected to the main waist rest 10 and the other end of which is connected to the connecting portion 10a, and the elastic deformation direction is substantially perpendicular to the backrest plate 30 (and the support beam 30d). The selection of the elastic modulus of the spring makes the main waist rest 10 not only provide a certain supporting force when the seated person leans back, so that the waist rest is not pressed too much by the waist of the seated person, causing the reverse arching of the spine (excessive deformation of the physiological curvature of the lumbar spine), but also provides a certain elasticity, so that the seated person does not feel that the waist rest is too large and uncomfortable.

[0051] As can be understood by those skilled in the art, the main waist rest 10 can push against the waist of the seated person (provide support for the waist) by virtue of the elastic restoring force provided by the elastic element 10c when people of different body types are seated. Even if the seated person's sitting posture is slightly offset, the main waist rest 10 will not easily come off the waist of the seated person (follow the waist of the seated person), thereby being able to prevent the seated person from sitting for a long time with the waist suspended, and being beneficial to the protection of the lumbar spine (and the cervical spine).

[0052] Referring to Figures 5 to 8 Further, as shown in the drawings, the auxiliary waist rest 20 includes a support body 21 arranged on both sides of the main waist rest 10, a connecting frame 22 connected to each support body 21, a transverse waist hole 20a formed on the connecting frame 22, and a pair of parallel guide rails 23 formed on one of the two connecting frames 22, the extension direction of the guide rails 23 being the same as the extension direction of the transverse waist hole 20a, so that the other can move transversely relative to the former under the guidance of the guide rails 23.

[0053] Further, the connecting frame 22 includes a first connecting rod 22a partially embedded in the support body 21, a second connecting rod 22b on which the transverse waist hole 20a is formed, and a plug block 24 formed on the exposed end of the first connecting rod 22a and one of the second connecting rods 22b, and a plug slot 25 formed on the other.

[0054] In this embodiment, the pair of parallel guide rails 23 are formed on the second connecting rod 22b on the right side, and are manifested as a pair of strip-shaped convex ribs arranged on the upper and lower edges of the second connecting rod 22b, which can also be regarded as strip-shaped flanges. In other embodiments, the pair of parallel guide rails 23 can also be formed on the second connecting rod 22b on the left side.

[0055] In this embodiment, one end of the first connecting rod 22a is embedded in the support body 21, and the other end is exposed from the support body 21. A columnar plug block 24 is formed on the other end exposed from the support body 21. A transverse waist hole 20a is formed on one end of the second connecting rod 22b, and a columnar plug slot 25 is formed on the other end. The plug block 24 can be inserted into the plug slot 25 from top to bottom or from bottom to top, thereby achieving the connection of the first connecting rod 22a and the second connecting rod 22b.

[0056] Further, after the plug block 24 is combined with the plug slot 25, an included angle is formed between the first connecting rod 22a and the second connecting rod 22b.

[0057] Those skilled in the art should understand that the setting of the guide rail 23 helps the two connecting frames 22 to keep moving along the extension direction of the transverse waist hole 20a, and the connecting frames 22 will not be deflected during the movement. The split type auxiliary waist rest 20 can make the support body 21 and the connecting frame 22 be made of different materials, the support body 21 is made of flexible material (for example, polyurethane and memory foam), and the connecting frame 22 is made of rigid material (for example, stainless steel or aluminum alloy). In this way, it is ensured that the auxiliary waist rest 20 has good supporting strength, and the support body 21 has good comfort when wrapping the waist of the seated person from both sides. The split type connecting frame 22 can be set to more angles between the first connecting rod 22a and the second connecting rod 22b, so that it can be selected according to the needs of the seated person.

[0058] Referring to Figures 1 to 4 Further, as shown in the figure, the protruding part 31 is formed on the backrest plate 30, the recessed part 32 is formed on both sides of the protruding part 31, the support beam 30d is embedded in the protruding part 31, and the second connecting rod 22b passes through the backrest plate 30 and can move transversely in the recessed part 32.

[0059] Those skilled in the art should understand that the recessed part 32 provides a space for the second connecting rod 22b extending out of the backrest plate 30 to accommodate and move, so that the second connecting rod 22b moves as much as possible to fit the backrest plate 30 (the front plate 30b), further enhances the stability of the movement, and also makes the second connecting rod 22b not easy to contact the body of the seated person.

[0060] Referring to Figures 1 to 3 Further, as shown in the figure, the seat backrest includes an inclined shoulder rest 50 arranged on the backrest plate 30, and the upper part of the shoulder rest 50 is more protruding than the lower part.

[0061] Those skilled in the art should understand that the upper part of the shoulder rest 50 is more protruding than the lower part, which can make its shape more consistent with the human body structure of the seated person whose back is excessively extended to the shoulder, and provide overall support for the seated person on the waist, back and shoulder.

[0062] Another embodiment of the present application provides an ergonomic chair, which includes any one of the seat backrests as described above.

[0063] Those skilled in the art should understand that the ergonomic seat has the same technical effects as the seat back as described above. For example, those skilled in the art should understand that the extension range of the vertical waist hole 30a is the adjustable moving range of the main waist rest 10 relative to the back plate 30 in the vertical direction. The extension range of the transverse waist hole 20a is the adjustable moving range of the auxiliary waist rest 20 relative to the main waist rest 10 in the transverse direction. That is, the connecting part 10a realizes both the connecting function and the sliding function, thereby simplifying the structure of the seat back and reducing the manufacturing cost.

[0064] In the description of the present specification, the description of the terms "certain embodiments", "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any suitable manner in any one or more embodiments or examples. In addition, the person skilled in the art can combine and combine the different embodiments or examples described in the present specification and the features of the different embodiments or examples without contradiction.

[0065] In the present application, the terms "first", "second", "third" are only for the purpose of description, and cannot be understood as indicating or implying relative importance; the term "multiple" means two or more, unless otherwise explicitly limited. The terms "mounting", "connecting", "connecting", "fixing" and the like should be broadly understood, for example, "connecting" can be fixed connection, can also be detachable connection, or integrally connected; "connected" can be directly connected, or indirectly connected through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application and are not limiting. Although the present application has been described in detail with reference to the embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present application, and they should be covered in the scope of the claims of the present application.

Claims

1. A seat backrest, characterized in that, include: Main lumbar support with connecting parts; A secondary lumbar support with horizontal waist holes; A backrest panel with vertical lumbar holes, wherein the connecting portion passes through the horizontal lumbar holes and the vertical lumbar holes to connect the main lumbar support, the secondary lumbar support, and the backrest panel together; and A fastener having a first mechanical coupling state and a second mechanical coupling state with the connecting portion, and configured as follows: When the two are in the first mechanical coupling state, the connecting part can move in the horizontal waist hole so that the secondary waist support can be adjusted in the horizontal direction relative to the main waist support. The connecting part can also move in the vertical waist hole so that the main waist support can be adjusted in the vertical direction relative to the backrest. When the two are in the second mechanical coupling state, the main lumbar support, the secondary lumbar support and the backrest are locked together.

2. The seat backrest according to claim 1, characterized in that: The length of the connecting part in the first direction is equal to the width of the vertical waist hole, and the length of the connecting part in the second direction is equal to the width of the horizontal waist hole.

3. The seat backrest according to claim 1, characterized in that: The main lumbar support is connected to the connecting part by an elastic element, and the main lumbar support can remain in close contact with the waist of the seated person under the action of the elastic element.

4. The seat backrest according to claim 1, characterized in that, The lumbar support includes: Supports are installed on both sides of the main lumbar support; A connecting frame is connected to each of the supports, the connecting frame having the transverse waist hole formed thereon, and a pair of parallel guide rails are formed on one of the two connecting frames, the extension direction of the guide rails being the same as the extension direction of the transverse waist hole, so that the other can move laterally relative to the former under the guidance of the guide rails.

5. The seat backrest according to claim 4, characterized in that, The connection framework includes: A first connecting rod partially embedded in the support body; A second connecting rod having the aforementioned transverse waist hole is provided. A plug-in block is formed on one of the exposed ends of the first connecting rod and the second connecting rod, and a plug-in groove matching the plug-in block is formed on the other end.

6. The seat backrest according to claim 5, characterized in that: After the plug-in block is engaged with the plug-in slot, an angle is formed between the first connecting rod and the second connecting rod.

7. The seat backrest according to claim 1, characterized in that, include: A support beam is fixedly embedded in the backrest panel, and a vertical waist hole is also formed on the support beam. The connecting part can pass through the horizontal waist hole and the vertical waist hole to connect the main waist backrest, the secondary waist backrest, the backrest panel and the support beam together.

8. The seat backrest according to claim 7, characterized in that: A protrusion is formed on the backrest panel, and recesses are formed on both sides of the protrusion. The support beam is embedded in the protrusion, and the second connecting rod passes through the backrest panel and can move laterally in the recesses.

9. The seat back according to claim 1, characterized in that, include: An inclined shoulder rest is provided on the backrest panel, the upper part of which protrudes more than the lower part.

10. An ergonomic chair, characterized in that, Includes the seat back as described in any one of claims 1 to 9.

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