CN210540079U - Chair back structure and chair - Google Patents

Abstract

The utility model discloses a chair back structure and a chair, which comprises a backrest and a waist rest, wherein the backrest comprises a back frame and a chair back support rod which is integrated with the back frame, the back frame comprises frame sides which are opposite at a left and a right interval and a top transverse part which is connected with the upper ends of the two frame sides; the waist rest is of a U-shaped structure with an open upper end, the waist rest comprises a transverse section and a longitudinal section extending upwards from two ends of the transverse section, the upper end of the longitudinal section is connected with the lower end of the frame side through a connecting piece, the upper end of the longitudinal section rotates around the lower end of the frame side, and a buffer mechanism is arranged between the upper end of the longitudinal section and the lower end of the frame side; the utility model discloses a chair back structure, because the waist rest is the U-shaped structure with the upper end open, the waist rest and the back frame are combined into a complete square structure, and a complete chair back frame structure is still formed from the appearance, thereby facilitating the integrated configuration of the mesh cloth; in addition, the waist support is rotatably connected with the back frame and matched with the buffer mechanism, so that the waist support can realize the self-adaptive support effect on the waist of the human body.

Description

Chair back structure and chair

Technical Field

The utility model relates to the field of furniture, in particular to back of chair structure and seat.

Background

The ergonomic chair is an indispensable product in office furniture, has wide comfortable functions and wide applicability, and is popular with consumers. The waist support chair in the current market is basically of a structure that a backrest and a waist support are completely separated, the backrest and the waist support are connected together through a spring and other structures, and the separated structure is designed to ensure that a certain hollow part is formed between the lower part of the backrest and the upper part of the waist support, so that the back or the waist of a user cannot be well supported in the using process; and the spring in the prior art is generally externally arranged at the rear end of the chair back, is very obvious and is not beautiful enough.

Specifically, for example, patent CN2728310Y discloses a multi-section chair back structure, in which a chair back plate 2 (corresponding to a "backrest") and a waist plate 3 (corresponding to a "waist rest") are completely separated, the chair back plate 2 and the waist plate 3 are connected by fittings such as an elastic rod 25, a cross rod 22 and a pivot joint 33, the waist plate 3 is elastically supported by the elastic rod 25, but the elastic rod 25 is disposed behind the chair back, which is obvious.

Furthermore, CN207870635U discloses an ergonomic chair, in which a waist support frame 5 and a back support frame 6 are of a split structure, the waist support frame 5 and the back support frame 6 are respectively fixed on a back support beam 4, lower transverse edges 601 of the back support beam 4 and the back support frame 6 are provided with arc-shaped supporting members 7, and the waist support frame 5 and the back support frame 6 support the waist and the back by the elastic deformation principle of the arc-shaped supporting members 7;

for example, patent CN106820697A discloses an intelligent health chair, in which the backrest part 4 and the lumbar part 5 are designed as separate bodies, wherein the lumbar part 5 is divided into left and right lumbar parts 51, 52, the left and right lumbar parts 51, 52 are fixed on the backrest support 2 through left and right reclining adjusting devices 53, 54, respectively, the backrest part 4 and the lumbar part 5 are mounted on the backrest support 2, and the backrest support 2 can rotate and drive the backrest part 4 and the lumbar part 5 to move through the reclining adjusting device 6, so as to achieve the purpose of supporting the waist and the back; however, in the embodiment of the patent, the reclining device 6 specifically adopts an angle adjuster used in an automobile seat, which is not a common structure, and has a complex structure and high cost;

although the above 3 patents can all achieve the function of supporting the waist and the back of a human body, the backrest and the waist rest are of split structures, the structure is complex, the number of accessories is large, and the cost is high during production and transportation; and after the backrest and the waist rest are designed in a split manner, a gap is easily generated between the waist and the backrest, so that the phenomenon that the back or the local waist of a human body is not supported by a supporting piece in the using process is caused.

Particularly, the backrest and the lumbar support are designed integrally, and the spring is hidden, so that the seat is simpler in manufacturing process and low in manufacturing cost, and the whole seat back looks more attractive while the better effects of the lumbar support and the backrest are achieved; designing a reasonably structured backrest structure is a technical problem to be solved currently.

SUMMERY OF THE UTILITY MODEL

The utility model overcomes the defects in the prior art, firstly, the chair back structure is provided, the waist rest and the backrest are integrated, and the problem of the split arrangement of the waist rest and the backrest in the prior art is solved; thereby reducing the cost, facilitating the integrated configuration of the mesh cloth, having no difference with the traditional mesh back, but increasing the function of the elastic waist support; and the buffer mechanism of the chair back structure is of a hidden design and is hidden in the chair back structure, and compared with the existing chair back structure, the hidden design is more attractive.

Still further, the utility model discloses provide a seat simultaneously again, the device uses with the cooperation of above-mentioned back of the chair structure, has simplified backrest and back of the waist structure in the past, can also satisfy the effect of supporting back, waist.

The technical scheme of the utility model is realized like this:

a chair back structure comprises a backrest and a waist rest, wherein the backrest comprises a back frame and a chair back support rod which is integrally formed with the back frame, the back frame comprises frame sides which are opposite to each other at a left-right interval and a top transverse piece which is connected to the upper ends of the two frame sides; the waist is by for the open U font structure in upper end, the waist is by including horizontal section and by the vertical section of horizontal section both ends upwards extension, and vertical section upper end passes through the connecting piece with frame side lower extreme and links to each other and vertical section upper end rotates around frame side lower extreme, is equipped with buffer gear between vertical section upper end and the frame side lower extreme simultaneously.

In the chair back structure of the utility model, the upper end of the longitudinal section of the waist rest is hung at the lower end of the frame side through the connecting piece, and the waist rest is in a U-shaped structure with an open upper end, so that the waist rest and the back frame form a complete square-shaped structure, and a complete chair back frame structure is still formed from the appearance, thereby facilitating the further integrated configuration of the screen cloth; in addition, the waist rest is rotatably connected with the back frame and is matched with the buffer mechanism, so that the waist rest can realize self-adaptive support effect on the waist of the human body, and the human body feels more comfortable; furthermore, the lower end of the waist rest is in a natural sagging state, the upper end of the waist rest is connected with the lower end of the backrest, and the buffer mechanism is hidden between the upper end of the waist rest and the lower end of the backrest, so that the whole body is more attractive.

Preferably, the buffer mechanism is a compression spring or a torsion spring. The buffer mechanism provides reset elasticity for the back and forth rotation of the waist support.

Preferably, the buffer mechanism adopts a pressure spring, and two ends of the pressure spring respectively abut against the inner surface of the upper end of the longitudinal section and the front surface of the lower end of the frame side. The compression spring is directly compressed when the waist rest rotates, and the elasticity of the compression spring directly acts on the waist rest forwards to help the waist rest to reset when the pressure disappears.

Preferably, the positioning device further comprises a positioning column and a cavity which are oppositely arranged, wherein the positioning column is arranged on one of the inner surface of the upper end of the longitudinal section or the front surface of the lower end of the frame side, and the cavity is arranged on the other of the inner surface of the upper end of the longitudinal section or the front surface of the lower end of the frame side; one end of the pressure spring is accommodated in the cavity, and the positioning column is inserted into the other end of the pressure spring. The cavity prevents that the pressure spring from deviating from between longitudinal segment and the frame side, and the reference column is inserted in the pressure spring other end, prevents that the pressure spring from sending the skew, further fixes a position the pressure spring, prevents that it from breaking away from the cavity.

Preferably, the length of the spring in a natural state is greater than that of the positioning column, and the length of the spring in a fully compressed state is greater than or equal to that of the positioning column. Thus, the positioning column can be ensured not to interfere the rotation of the waist rest.

Preferably, the connecting piece is a strip-shaped connecting plate, the upper end of the connecting piece upwards exceeds the upper end of the longitudinal section and is fixedly connected with the front surface of the lower end of the frame side through a first screw, the lower end of the connecting piece is attached to the outer surface of the upper end of the longitudinal section and penetrates through the upper end of the longitudinal section through a second screw to be in threaded connection with the lower end of the frame side, and a waist-shaped groove for the second screw to penetrate through and for avoiding the second screw when the waist rest rotates is formed in the upper end of the longitudinal section. The height of the waist-shaped groove is larger than the width of the waist-shaped groove, and the generated avoidance gap can enable the second screw to have an avoidance space in the process of rotating the waist; specifically, the upper end and the lower end of the connecting piece are respectively provided with a first mounting hole and a second mounting hole, and the front surface of the lower end of the corresponding frame side is provided with a first screw hole and a second screw hole; the connecting piece is connected with the frame side through the first screws, and then the lower end of the connecting piece is connected with the upper end of the longitudinal section and the lower end of the frame side through the second screws in sequence.

Preferably, still include an arc arch and avoid the breach with it complex, the arc arch rotates around avoiding the breach, be equipped with an inner chamber that holds the connecting piece latter half on the surface of longitudinal segment upper end, the arc arch setting on one of inner chamber end or connecting piece internal surface, avoid the breach setting on another in inner chamber end or connecting piece internal surface. The arc-shaped protrusion forms a rotating shaft, so that the waist rest can rotate orderly when rotating, and the connecting piece can serve as a rotary support of the waist rest, thereby achieving two purposes at one stroke.

Preferably, the arcuate projections are disposed adjacent the upper surface of the longitudinal segments. Therefore, the rotating point is positioned at the upper end of the longitudinal section, and the tilting amplitude of the upper end of the longitudinal section is limited when the longitudinal section rotates, so that the connecting piece is not obtrusive and cannot be influenced.

Preferably, a groove is formed in the front surface of the lower end of the frame side, the groove comprises a shallow upper groove and a deep lower groove, the shape and the size of the upper groove are matched with those of the upper half part of the connecting piece, the shape and the size of the lower groove are matched with those of the upper end of the longitudinal section, the outer surface of the upper end of the longitudinal section is flush with the bottom of the upper groove after the upper end of the longitudinal section is buckled in the lower groove. The longitudinal section of the waist support and the connecting piece can be hidden in the groove by the arrangement, so that the waist support and the backrest can form a whole, the mesh cloth is more beneficial to configuration, and after the waist support and the backrest are installed, the outer surface of the connecting piece, the outer surface of the longitudinal section and the front surface of the frame side are positioned on the same surface, so that the mesh cloth does not protrude outwards at the junction of the backrest and the waist support.

Preferably, a side stop is formed in the recess on the side thereof adjacent to the outer peripheral edge of the frame side, said side stop being higher than the recess. The side block can block a part of the upper end of the longitudinal section to prevent hands from being clamped.

Preferably, the thickness of the lower half part of the connecting piece is gradually reduced from top to bottom, a slope is correspondingly arranged in the inner cavity, and the inner surface of the lower half part of the connecting piece is abutted against the slope in a free state. The lower half part of the connecting piece becomes thin to reserve space for the rotation of the longitudinal section, and meanwhile, the rotation of the longitudinal section can be limited.

Preferably, the longitudinal section is in the shape of a forward convex arc. So that the supporting and supporting can be formed for the waist of the human body after the mesh cloth is arranged.

Preferably, the frame further comprises clamping strips and a mesh, clamping grooves are formed in the front surface of the side of the frame, the front surface of the top transverse part, the outer surfaces of the longitudinal section and the outer surfaces of the transverse sections, and the mesh is clamped in the clamping grooves by means of the clamping strips.

Preferably, the upper end of the backrest support rod is formed with two forked rods extending obliquely forward, the forked rods are connected with the lower end of the frame side, and a space is reserved between the waist rest and the backrest support rod. The chair back support rod provides integral support, and the crotch rod extends forwards obliquely to leave a gap between the waist support and the chair back support rod, so that the rotation of the waist support is not hindered.

A seat comprises the chair back structure.

Adopted above-mentioned technical scheme the utility model discloses a design departure point, theory and beneficial effect are:

the chair back structure of the utility model integrates the backrest and the waist rest, requires fewer accessories, reduces the cost, and also leads the whole chair back structure to be simpler and the waist rest line to be smoother due to the integrated design; the lower edge of the backrest is the upper edge of the waist support, and the backrest and the waist support are connected in a seamless manner, so that the back and the waist of a user can be completely supported in the using process, and the support effect of the chair back structure on a human body is better; just the utility model discloses an elastic construction hides inside the back of the chair to it is comparatively succinct, pleasing to the eye on the whole.

Drawings

Fig. 1 is an exploded perspective view of an embodiment of the present invention;

fig. 2 is a schematic view of a back-to-back three-dimensional structure in an embodiment of the present invention;

fig. 3 is a schematic view of a waist rest in an embodiment of the present invention;

fig. 4 is a schematic perspective view of a connecting member according to an embodiment of the present invention;

fig. 5 is a schematic perspective view of the seat according to the embodiment of the present invention after partially cutting;

fig. 6 is a schematic perspective view of a seat according to an embodiment of the present invention;

fig. 7 is a schematic perspective view of the embodiment of the present invention, wherein the backrest and the waist rest are combined, and the connecting member is installed on one side, and the connecting member is not installed on one side;

fig. 8 is a schematic perspective view of the backrest and the lumbar support of the present invention after being combined in an embodiment;

FIG. 9 is an enlarged view of a portion a of FIG. 1;

FIG. 10 is an enlarged view of the portion b in FIG. 2;

FIG. 11 is an enlarged view of the portion c of FIG. 3;

fig. 12 is a front view of a connector according to an embodiment of the present invention;

fig. 13 is a cross-sectional view of a kidney groove in an embodiment of the present invention;

the figures are numbered: backrest 1, backrest lower end 1a, connecting member 2, connecting member upper end 2a, connecting member lower end 2B, connecting member outer surface 201, connecting member inner surface 202, first and second mounting holes 201a, 202B, lumbar support 3, lumbar support lower end 3a, lumbar support upper end 3B, transverse section 301, transverse section outer surface 301a, longitudinal section 302, longitudinal section upper end 302a, longitudinal section upper end inner surface 302B, longitudinal section upper end outer surface 302c, longitudinal section upper end upper surface 302d, buffer mechanism 4, end a, end B, back frame 5, first screw hole 5a, second screw hole 5B, frame side 501, frame side lower end 501a, frame side lower end front surface 501B, top transverse member 502, top transverse member front surface 502a, back support bar 6, mesh 7, positioning post 8, cavity 9, first screw 10, second screw 11, waist-shaped groove 12, height 12a, Width 12b, protrusion 13, relief notch 14, cavity 15, groove 16, upper groove 16a, lower groove 16b, side stop 17, ramp 18.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention more clearly understood, the present invention will be described in further detail with reference to the accompanying drawings and detailed description. It should be noted that the embodiments and features of the embodiments of the present application may be combined with each other without conflict.

In the description of the present invention, the term "at least one" means one or more unless explicitly defined otherwise. The terms "first," "second," "third," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

The specific implementation manner of the utility model is as follows:

as shown in fig. 1-4 and 7-13, the present embodiment first provides a chair back structure, which includes a backrest 1 and a lumbar support 3, wherein the backrest 1 includes a back frame 5 and a chair back support bar 6 connected thereto, the back frame 5 includes frame sides 501 opposite to each other at a left-right interval, and a top cross member 502 connected to upper ends of the two frame sides 501; the lumbar support 3 is of a U-shaped structure with an open upper end, the lumbar support 3 comprises a transverse section 301 and an arc-shaped longitudinal section 302 extending upwards from two ends of the transverse section 301, and the arc-shaped longitudinal section is in a forward convex shape, so that a supporting support can be formed for the waist of a human body after mesh cloth (not shown) is arranged; the upper end 302a of the longitudinal section is connected with the lower end 501a of the frame side through the connecting piece 2, the upper end 302a of the longitudinal section rotates around the lower end 501a of the frame side, meanwhile, a buffer mechanism 4 is arranged between the upper end 302a of the longitudinal section and the lower end 501a of the frame side, and the buffer mechanism 4 in the embodiment adopts a pressure spring and can provide reset elasticity for the front and back rotation of the lumbar support 3.

Two crotch bars 66 extending obliquely forward are formed at the upper end of the back support bar 6, the crotch bars 66 are connected to the lower end of the frame side 501, and a space 77 is left between the lumbar support 3 and the back support bar 6. That is, the back support rod 6 provides the whole support, and the crotch rod extends obliquely forward to form a space 77 between the lumbar support 3 and the back support rod 6, so that the rotation of the lumbar support 3 is not hindered.

In addition, the positioning column 8 is arranged on the inner surface 302b of the upper end of the longitudinal section, and the cavity 9 is arranged on the front surface 501b of the lower end of the frame side; one end 4a of the pressure spring is accommodated in the cavity 9, the positioning column 8 is inserted into the other end 4b of the pressure spring, the length of the pressure spring in a natural state is greater than that of the positioning column 8, and the length of the pressure spring in a fully compressed state is greater than or equal to that of the positioning column 8. This ensures that the positioning post 8 does not interfere with the rotation of the lumbar support 3. The cavity 9 prevents the compression spring from falling out between the longitudinal section 302 and the frame side 501, and the positioning column 8 prevents the compression spring from shifting, so that the compression spring is further positioned and prevented from falling out of the cavity 9.

The compression spring is directly compressed when the lumbar support 3 rotates, and the elasticity of the compression spring directly acts on the lumbar support 3 forwards to help the lumbar support 3 reset when the pressure disappears. The upper end 302a of the longitudinal section of the waist support 3 is hung at the lower end 501a of the frame side through the connecting piece 2, and the waist support 3 is of a U-shaped structure with an open upper end, so that the waist support 3 and the back frame 5 are connected together to form a complete square-shaped structure, and a complete chair back frame structure is still formed in appearance, so that the mesh cloth (not shown) can be conveniently and integrally configured; in addition, the waist rest 3 is rotationally connected with the back frame 5 and matched with the pressure spring, so that the waist rest 3 can realize self-adaptive support effect on the waist of the human body, and the human body feels more comfortable; furthermore, the lower end 3a of the waist rest is in a natural drooping state, the upper end 3b of the waist rest is connected with the lower end 1a of the backrest, and the buffer mechanism 4 is hidden between the two, so that the whole body is more attractive.

The connecting piece 2 is a strip-shaped connecting plate, the upper end 2a of the connecting piece upwards exceeds the upper end 302a of the longitudinal section and is fixedly connected with the front surface 501b of the lower end of the frame side through a first screw 10, the lower end 2b of the connecting piece is attached to the outer surface 302c of the upper end of the longitudinal section and is connected with the lower end 501a of the frame side through a second screw 11 passing through the upper end 302a of the longitudinal section, and the upper end 302a of the longitudinal section is provided with a waist-shaped groove 12 for the second screw 11 to pass through and for avoiding the second screw 11 when the waist rest 3 rotates. The height 12a of the waist-shaped groove 12 is larger than the width 12b thereof, and the generated avoidance gap can ensure that the second screw 11 has an avoidance space in the rotation process of the lumbar support 3; specifically, the upper end 2a and the lower end 2b of the connecting piece are respectively provided with a first mounting hole 201a and a second mounting hole 202b, and the front surface 501b of the lower end of the corresponding frame side is provided with a first screw hole 5a and a second screw hole 5 b; the connecting member 2 is connected to the frame side 501 by first screws 10, and then the lower end 2b of the connecting member is connected to the upper end 302a of the longitudinal section and the lower end 501a of the frame side by second screws 11.

Still include one set up near the protruding 13 of arc and the matched avoidance breach 14 of longitudinal segment upper end upper surface 302d department, the protruding 13 of arc is equipped with an inner chamber 15 that holds the connecting piece 2 the latter half on longitudinal segment upper end surface 302c around avoiding the breach 14 rotation, and protruding 13 of arc sets up at the bottom of inner chamber 15 chamber, avoids breach 14 to set up on connecting piece internal surface 202. The arc-shaped bulge 13 forms a rotating shaft, the rotating point is positioned at the upper end 302a of the longitudinal section, and the upwarp amplitude of the upper end of the longitudinal section 302 is limited when the longitudinal section rotates, so that the connecting piece 2 is not influenced by a sharp feeling; the waist leans on 3 when rotating, can rotate in order, and connecting piece 2 plays two birds with one stone as the rotatory support of waist leans on 3 simultaneously. The thickness of the lower half 55 of the connecting element 2 is gradually reduced from top to bottom, a slope 18 is correspondingly arranged in the inner cavity 15, and the inner surface of the lower half of the connecting element 2 is abutted against the slope 18 in a free state. The thinning of the lower half of the link 2 leaves room for the longitudinal section 302 to rotate and at the same time provides a limit to the rotation of the longitudinal section 302.

The frame side lower end front surface 501b is provided with a groove 16, the groove 16 comprises a shallow upper groove 16a and a deep lower groove 16b, the upper groove 16a is matched with the shape and size of the upper half part of the connecting piece 2, the lower groove 16b is matched with the shape and size of the upper end 302a of the longitudinal section, and after the upper end 302a of the longitudinal section is buckled in the lower groove 16b, the outer surface 302c of the upper end of the longitudinal section is flush with the bottom of the upper groove 16 a. This arrangement allows the longitudinal section 302 of the lumbar support 3 and the connecting member 2 to be hidden in the recess 16, which facilitates the formation of a single piece with the backrest 1, and is more advantageous for the arrangement of a mesh (not shown).

As shown in fig. 7, when installed, the outer surface 201 of the connecting member, the outer surface 302c of the upper end of the longitudinal section and the front surface 501b of the frame side are in the same plane, so that the mesh (not shown) does not protrude outward at the junction of the backrest 1 and the lumbar support 3.

A side stop 17 is formed in the recess 16 on the side thereof adjacent the outer periphery of the frame side 501, said side stop 17 being elevated above the recess 16. The side stop 17 can stop a part of the upper end of the longitudinal section 302, thereby reducing the exposure of the seam and preventing the hand from being clamped.

The frame comprises a front surface of the frame side 501, a front surface of the top transverse member, the longitudinal section 302 and the outer surface 301a of the transverse section, and clamping grooves (not shown) in which the mesh (not shown) is clamped by the clamping strips.

As shown in fig. 5 and 6, the present embodiment further provides a seat comprising the seat back structure described above.

Claims (13)

1. The utility model provides a back of chair structure, includes back, waist and leans on, its characterized in that: the backrest comprises a back frame and a backrest support rod connected with the back frame, and the back frame comprises frame sides which are opposite at a left-right interval and a top transverse part connected to the upper ends of the two frame sides; the waist is by for the open U font structure in upper end, the waist is by including horizontal section and by the vertical section of horizontal section both ends upwards extension, and vertical section upper end passes through the connecting piece with frame side lower extreme and links to each other and vertical section upper end rotates around frame side lower extreme, is equipped with buffer gear between vertical section upper end and the frame side lower extreme simultaneously.

2. The chair back structure of claim 1, wherein: the buffer mechanism is a pressure spring or a torsion spring.

3. The chair back structure of claim 2, wherein: the buffer mechanism adopts a pressure spring, and two ends of the pressure spring respectively abut against the inner surface of the upper end of the longitudinal section and the front surface of the lower end of the frame side.

4. The chair back structure of claim 3, wherein: the positioning column is arranged on one of the inner surface of the upper end of the longitudinal section or the front surface of the lower end of the frame side, and the cavity is arranged on the other one of the inner surface of the upper end of the longitudinal section or the front surface of the lower end of the frame side; one end of the pressure spring is accommodated in the cavity, and the positioning column is inserted into the other end of the pressure spring.

5. The chair back structure of claim 4, wherein: the length of the pressure spring in a natural state is larger than that of the positioning column, and the length of the spring in a fully compressed state is larger than or equal to that of the positioning column.

6. The chair back structure of claim 1, wherein: the connecting piece be a rectangular form connecting plate, the connecting piece upper end upwards surpasss vertical section upper end and links to each other through first screw and frame side lower extreme front surface is fixed, the connecting piece lower extreme pastes in vertical section upper end surface and passes vertical section upper end and frame side lower extreme threaded connection through the second screw, open the waist type groove that supplies the second screw to pass and be used for dodging the second screw when the waist leans on the rotation on the upper end of vertical section.

7. The chair back structure of claim 6, wherein: still include an arc arch and dodge the breach with it complex, the arc arch rotates around dodging the breach, be equipped with an inner chamber that holds the connecting piece the latter half on the surface of longitudinal section upper end, the arc arch set up at the bottom of the inner chamber or on one of them in the connecting piece internal surface, dodge the breach setting at the bottom of the inner chamber or on another in the connecting piece internal surface.

8. The chair back structure of claim 7, wherein: the arc-shaped bulge is arranged at a position close to the upper surface of the longitudinal section.

9. The chair back structure of claim 7, wherein: the frame side lower extreme front surface be equipped with the recess, the recess include shallower upper groove and darker lower groove, upper groove and connecting piece first half shape, size match, lower groove and vertical section upper end shape, size match, after vertical section upper end lock is in the inslot down, vertical section upper end surface and upper groove tank bottom parallel and level.

10. The chair back structure of claim 9, wherein: a side stop is formed on the side of the groove close to the outer periphery of the frame side, said side stop being higher than the groove.

11. The chair back structure of claim 7, wherein: the thickness of the latter half of connecting piece from top to bottom thins gradually, corresponds in the cavity and is equipped with a slope, and under free state, the internal surface of connecting piece the latter half offsets with the slope.

12. The chair back structure of claim 1, wherein: the longitudinal section is in a forward convex arc shape.

13. A seat, characterized by: comprising a chair back structure as claimed in any one of claims 1 to 12.

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