CN110200435A - A kind of back structure and seat - Google Patents

Abstract

The invention discloses a kind of back structure and seats, including lean against, Lumbar, it is described lean against including back frame and with its integrally formed back support bar, the back frame includes every opposite frame side and being connected to the top cross-member of two frame sides upper end between left and right；The Lumbar is the U-shaped structure of open upper end, the Lumbar includes traversing section and the longitudinal sections that are upwardly extended by traversing section both ends, longitudinal sections upper end is connected with frame side lower end by connector and longitudinal sections upper end is rotated around frame side lower end, while buffer gear is equipped between longitudinal sections upper end and frame side lower end；Back structure of the invention, since the U-shaped structure that Lumbar is upper end opening from without, still forms a complete seat back frame structure, facilitate unified collocation screen cloth so Lumbar and back frame are combined into a complete buccal glyph shaped structure；In addition, Lumbar and back frame rotation connection cooperation buffer gear allow Lumbar to realize adaptive supporting role to human body waist.

Description

A kind of back structure and seat

Technical field

The present invention relates to field of furniture, in particular to a kind of back structure and seat.

Background technique

Ergonomic side chair is as a product indispensable in office furniture, comfortable function wide applicability, Obtain liking for the majority of consumers.Waist protecting chair currently on the market is substantially and leans against the structure completely seperated with Lumbar, the two Between linked together by structures such as springs, separate structure design so that being formed between the top of the lower part and Lumbar that lean against Certain hollow out, so that user is during use, back or waist have portion that cannot preferably prop up Support；And the spring of the prior art is usually the rear end for being placed outside the chair back, it will thus be apparent that not beautiful enough.

Specifically, for example patent CN2728310Y discloses a kind of Multi-section type chair back structure, the back structure in the patent, Chair back plate 2 (being equivalent to " leaning against ") and waist panel 3 (being equivalent to " Lumbar ") are distinct two structures, by elastic rod 25, The accessories such as cross bar 22 and articulated part 33 connect chair back plate 2 with waist panel 3, and waist panel 3 is flexibly supported by elastic rod 25, But elastic rod 25 is arranged in behind the chair back, more obviously.

Further more, CN207870635U discloses a kind of Ergonomic chair, and in the seat, waist holding frame frame 5 and back bracket frame Frame 6 is seperated structure, and waist holding frame frame 5 and back bracket frame 6 are separately fixed on back support beam 4, back support beam 4 and back The lower horizontal edge 601 of holding frame frame 6 is equipped with curved support part 7, by the flexible deformation principle of curved support part 7, so that waist holding frame frame 5 Play the role of support to waist, back with back bracket frame 6.

Such as patent CN106820697A discloses a kind of intelligent health chair again, in the health seat, backrest part 4 and waist The design seperated by component 5, wherein Lumbar component 5 divides for left and right waist lever 51,52, and 51,52 points of left and right waist lever Regulating device 53,54 is not leaned on to be fixed in back support 2 by left and right, backrest part 4, Lumbar component 5 are mounted on the chair back In support 2, the rotation of back support 2 can be made by lying down regulating device 6 while backrest part 4 and Lumbar component 5 being driven to move, from And achieve the purpose that support waist and back；But regulating device 6 is lied down in the embodiment of the patent specifically using automotive seats Angle adjustor used in chair is not common structure, and structure is complex at high cost.

In addition, patent CN207613490U discloses a kind of back structure, in the back structure, back cushion 20 (is equivalent to " leaning against ") to rest the head on 30 (being equivalent to " Lumbar ") with waist be seperated structure, back cushion 20 and waist rest the head on 30 can be simultaneously relative to chair back sheet Body 10 slides up and down, and chair back ontology 10 is equipped with sliding slot, and back cushion 20 and waist pillow 30 are equipped with the convex block portion 21 to match with sliding slot, sliding Dynamic principle makes back cushion 20 and waist rest the head on 30 up and down motions to play the role of support.

For another example patent CN208114377U discloses a kind of ergonomics fission supporting structure of chair back, the back support In structure, leaning against support portion 3 with Lumbar support portion 4 is seperated design, and when needing to be adjusted the chair back, which needs After being first adjusted by operation adjustment mechanism to back support bar 1, the chair back and Lumbar is driven to reach support human body waist, back Effect；Back support bar 1 is set to behind the chair back, is leaned against since it needs to support, Lumbar, so Design of length is wider, It exposes to behind the chair back, unsightly；

Although above 5 patents are attained by the effect of support human body waist, back, but lean against the knot with Lumbar fission Structure, and structure is complex, number of fitting parts is more, the higher cost in production and transportation；And after leaning against design seperated with Lumbar, Waist and gap is easy to produce between leaning against, so as to cause during use, human body back or waist local location do not have The phenomenon that supports support.

Ad hoc to want to be integrally designed with Lumbar using leaning against, spring hides design, so that seat manufacture craft is more succinct, manufacture It is at low cost, and with preferable Lumbar, lean against effect while the chair back integrally seem more aesthetically pleasing；So design a knot Structure is reasonable and the back structure of buffering supporting role can be played to human body waist is the current technical issues that need to address.

Summary of the invention

The present invention overcomes the deficiencies in the presence of the above-mentioned prior art, a kind of back structure are provided firstly, using waist It leans on, lean against and be structure as a whole, solve the problems, such as split settings both in the prior art；To reduce costs, and it is square Just unified collocation screen cloth and traditional net back are not different, but increase the function of elastic waist support；And the back structure Buffer gear is concealed design, is hidden in inside back structure, and existing back structure is compared, and concealed design is more beautiful It sees.

It further says, the present invention provides a kind of seat again simultaneously, which is used cooperatively with above-mentioned back structure, letter Previous backrest and back structure are changed, additionally it is possible to meet the effect at support back, waist.

The technical scheme of the present invention is realized as follows:

A kind of back structure, including lean against, Lumbar, it is described lean against including back frame and with its integrally formed back support Bar, the back frame include every opposite frame side and being connected to the top cross-member of two frame sides upper end between left and right；It is described Lumbar is the U-shaped structure of open upper end, and the Lumbar includes traversing section and the longitudinal sections that are upwardly extended by traversing section both ends, is indulged It is connected to section upper end with frame side lower end by connector and longitudinal sections upper end is rotated around frame side lower end, while longitudinal sections upper end Buffer gear is equipped between the lower end of frame side.

The longitudinal sections upper end of back structure of the invention, Lumbar is hung on frame side lower end by connector, due to Lumbar For the U-shaped structure of upper end opening, so Lumbar and back frame are combined into a complete buccal glyph shaped structure, from without, still group At a complete seat back frame structure, facilitate further unified collocation screen cloth；In addition, Lumbar and back frame rotation connection cooperate Buffer gear allows Lumbar to realize adaptive supporting role to human body waist, keeps human body sensory more comfortable；Further Say, Lumbar lower end is in and naturally droops state, Lumbar upper end with lean against that lower end is connected and buffer gear is hidden between the two, make It is whole more attractive.

Preferably, the buffer gear is pressure spring or torsional spring.Buffer gear provides reset bullet for the front and back rotation of Lumbar Power.

Preferably, the buffer gear use pressure spring, the both ends of pressure spring respectively with longitudinal sections upper end inner surface, frame side Lower end front surface offsets.Lumbar direct compression press spring when rotating, the direct forward action of elastic force of pressure spring is in Lumbar when pressure disappears Lumbar is helped to reset.

Preferably, further including having the positioning column and cavity being arranged oppositely, the positioning column is set to longitudinal sections upper end In one of them of inner surface or frame side lower end front surface, cavity is then set to longitudinal sections upper end inner surface or frame side lower end On another of front surface；One end of pressure spring is placed in cavity, and positioning column is then inserted in the other end of pressure spring.Cavity prevents from pressing Spring is deviate between longitudinal sections and frame side, and positioning column is inserted in the pressure spring other end, pressure spring sending deviation is prevented, further to pressure spring It is positioned, it is prevented to be detached from cavity.

Preferably, the spring in its natural state length be greater than positioning column length and spring in complete compressive state Under length be greater than or equal to positioning column length.It can guarantee that positioning column does not interfere with the rotation of Lumbar in this way.

Preferably, the connector is a strip connecting plate, connector upper end exceeds longitudinal sections upper end simultaneously upwards It is fixedly linked by the first screw and frame side lower end front surface, connector lower end is affixed on longitudinal sections upper end outer surface and by the Two-screw passes through longitudinal sections upper end and connect with frame side lower thread, is provided in longitudinal sections upper end and passes through and be used for for the second screw The waist type groove of the second screw is avoided in Lumbar rotation.The height of waist type groove is greater than its width, and the evacuation gap of generation can make Obtain Lumbar in the course of rotation, the second screw has avoiding space；Specifically, connector upper and lower end is respectively provided with first, second Mounting hole, corresponding frame side lower end front surface are equipped with the first screw hole, the second screw hole；The first screw is first passed through by connector and frame Frame side is connected, and then successively connector lower end and longitudinal sections upper end, frame side lower end are linked together with the second screw again.

Preferably, further including an arc convex and matched evacuation notch, arc convex is rotated around evacuation notch, Longitudinal sections upper end outer surface is equipped with an inner cavity for accommodating connector lower half portion, and the arc convex is arranged in inner cavity In one of them in bottom of chamber or connector inner surface, the evacuation notch is arranged in inner cavity bottom of chamber or connector inner surface Another on.Arc convex forms shaft, and Lumbar can be achieved in this way in rotation, can orderly rotate, while connector is made It supports, kills two birds with one stone for the rotation of Lumbar.

Preferably, the arc convex is positioned close at the position of longitudinal sections upper surface.Make to rotate point in this way In longitudinal sections upper end, the upper end tilts limited extent when longitudinal sections rotate, and does not have lofty sense, will not cause shadow to connector It rings.

Preferably, be equipped with groove in frame side lower end front surface, the groove includes shallower upper slot and deeper Lower slot, the upper slot are matched with connector top half shape, size, and lower slot is matched with longitudinal sections upper end shape, size, are indulged After being fastened in lower slot to section upper end, longitudinal sections upper end outer surface is concordant with upper slot slot bottom.Setting makes it possible to Lumbar in this way Longitudinal sections and connector are hidden in groove, conducive to lean against shape integral, more beneficial to configuring screen cloth, after installation, connector Outer surface, longitudinal sections outer surface and frame side front surface are on the same face so that screen cloth lean against, Lumbar intersection is without outer It is convex.

Preferably, being formed with side block in this side of the close frame side outer peripheral edge of groove, the side block is higher by recessed Slot.Side block, which can be blocked, blocks a part for longitudinal sections upper end, prevents clamp hand.

Preferably, the thickness of the lower half portion of connector is gradually thinning from top to bottom, it is intracavitary inside to be correspondingly provided with one tiltedly Slope, in a free state, connector lower half portion inner surface are supported with Slope Facies.Connector lower half portion is thinning to be rotated to longitudinal sections Slot milling, and simultaneously longitudinal sections can be rotated to form limit.

Preferably, the longitudinal sections are the arcuate shape of lordosis.So that can be to human body waist shape after configuration screen cloth It is supported at support.

Preferably, further include having strip and screen cloth, front surface, top cross-member front surface and longitudinal direction in frame side Section, traversing section outer surface are equipped with card slot, and the screen cloth is stuck in the card slot by strip.

Preferably, the upper end of back support bar forms two extendable diagonally forward headtrees, the headtree and frame Frame side lower end is connected, spaced between Lumbar and back support bar.Back support bar provides integrated support, and headtree is diagonally forward Extend so that spaced between Lumbar and back support bar, Lumbar rotation is not caused to hinder.

A kind of seat, including the back structure.

It is using design starting point of the invention, theory and the beneficial effect of above-mentioned technical proposal:

Back structure of the invention will lean against with Lumbar integrated design, the number of fitting parts needed is less, reduce costs, And the design of one, but also back structure is whole more succinct, Lumbar lines are more smooth；The lower edge leaned against is Lumbar Upper edge is seamlessly connected therebetween, so that during use, the back of user and waist can obtain whole branch Support, so that the back structure is more preferable to the support effect of human body；And elastic construction of the invention is hidden in inside the chair back, thus whole It is more succinct on body, beautiful.

Detailed description of the invention

Fig. 1 is the stereochemical structure perspective view of the explosion of the present invention in embodiment；

Fig. 2 be the present invention in embodiment lean against schematic perspective view；

Fig. 3 is the Lumbar schematic perspective view of the present invention in embodiment；

Fig. 4 is the connector schematic perspective view of the present invention in embodiment；

Fig. 5 is the schematic perspective view after seat part section in embodiment of the invention；

Fig. 6 is the schematic perspective view of seat in embodiment of the invention；

Fig. 7 is that the present invention leans against combine with Lumbar and side installs connector, the side not yet company of installation in embodiment The schematic perspective view of fitting；

Fig. 8 is that the present invention leans against the schematic perspective view after combining with Lumbar in embodiment；

Fig. 9 is the portion a enlarged diagram in Fig. 1；

Figure 10 is the portion b enlarged diagram in Fig. 2；

Figure 11 is the portion c enlarged diagram in Fig. 3；

Figure 12 is the main view of connector in embodiment of the invention；

Figure 13 is the sectional view of waist type groove in embodiment of the invention；

Each appended drawing reference are as follows: lean against 1, lean against lower end 1a, connector 2, connector upper end 2a, connector lower end 2b, connection Part outer surface 201, connector inner surface 202, first, second mounting hole 201a, 202b, Lumbar 3, Lumbar lower end 3a, in Lumbar Hold 3b, traversing section 301, traversing section outer surface 301a, longitudinal sections 302, longitudinal sections upper end 302a, longitudinal sections upper end inner surface 302b, longitudinal sections upper end outer surface 302c, longitudinal sections upper end upper surface 302d, buffer gear 4, the end the A end 4a, B 4b, back frame 5, One screw hole 5a, the second screw hole 5b, frame side 501, frame side lower end 501a, frame side lower end front surface 501b, top cross-member 502, top cross-member front surface 502a, back support bar 6, screen cloth 7, positioning column 8, cavity 9, the first screw 10, the second screw 11, waist type groove 12, height 12a, width 12b, protrusion 13, evacuation notch 14, inner cavity 15, groove 16, upper slot 16a, lower slot 16b, Side block 17, slope 18.

Specific embodiment

To better understand the objects, features and advantages of the present invention, with reference to the accompanying drawing and specific real Applying mode, the present invention is further described in detail.It should be noted that in the absence of conflict, the implementation of the application Feature in example and embodiment can be combined with each other.

In the description of the present invention, term "at least one" refers to one or more, unless otherwise restricted clearly.Art Language " first ", " second ", " third " etc. are only used for the purpose of description, are not understood to indicate or imply relative importance.

A specific embodiment of the invention is as follows:

Picture 1-4, shown in 7-13, the present embodiment provides firstly a kind of back structure, including leans against 1, Lumbar 3, described Leaning against 1 includes back frame 5 and coupled back support bar 6, and the back frame 5 includes between left and right every opposite frame side 501 And it is connected to the top cross-member 502 of two frame sides, 501 upper end；The Lumbar 3 is the U-shaped structure of open upper end, described Lumbar 3 includes traversing section 301 and the longitudinal sections 302 by the arc that the shape that 301 both ends of traversing section upwardly extend is lordosis, arc Shape designs so that can form support support after configuration screen cloth (not shown) to human body waist；Longitudinal sections upper end 302a and frame side Lower end 501a is connected by connector 2 and longitudinal sections upper end 302a is rotated around frame side lower end 501a, while longitudinal sections upper end Buffer gear 4 is equipped between 302a and frame side lower end 501a, it can be Lumbar 3 that buffer gear 4, which uses pressure spring, in the present embodiment Front and back rotation provide reseting elasticity.

The upper end of back support bar 6 forms two extendable diagonally forward headtrees 66, the headtree 66 and frame side 501 lower ends are connected, spaced 77 between Lumbar 3 and back support bar 6.I.e. back support bar 6 provides integrated support, bifurcated Bar is extendable diagonally forward so that Lumbar 3 and the formation of back support bar 6 interval 77, do not cause to hinder to the rotation of Lumbar 3.

In addition, further including being located at the positioning column 8 of longitudinal sections upper end inner surface 302b and being located at frame side lower end front surface Cavity 9 on 501b；One end 4a of pressure spring is placed in cavity 9, and positioning column 8 is then inserted in the other end 4b of pressure spring and pressure spring exists The length of length and pressure spring under complete compressive state that length is greater than positioning column 8 under natural conditions is greater than or equal to positioning column 8 Length.It can guarantee that positioning column 8 does not interfere with the rotation of Lumbar 3 in this way.Cavity 9 prevents pressure spring abjection longitudinal sections 302 and frame Between frame side 501, positioning column 8 then prevents pressure spring sending deviation, further positions to pressure spring, it is prevented to be detached from cavity 9.

Direct compression press spring when rotating of Lumbar 3, the direct forward action of elastic force of pressure spring is helped in Lumbar 3 when pressure disappears Lumbar 3 resets.The longitudinal sections upper end 302a of Lumbar 3 is hung on frame side lower end 501a by connector 2, since Lumbar 3 is upper Open U-shaped structure is held, so Lumbar 3 and back frame 5 are combined into a complete buccal glyph shaped structure after linking together, from appearance From the point of view of, a complete seat back frame structure is still formed, further unified collocation screen cloth (not shown) is facilitated；In addition, Lumbar 3 Being rotatablely connected cooperation pressure spring with back frame 5 allows Lumbar 3 to realize adaptive supporting role to human body waist, makes human body sensory more It is comfortable；Further say, Lumbar lower end 3a is in and naturally droops state, Lumbar upper end 3b with lean against lower end 1a and be connected and buffer Mechanism 4 is hidden between the two, is made whole more attractive.

The connector 2 is a strip connecting plate, and connector upper end 2a exceeds longitudinal sections upper end 302a upwards and leads to It crosses the first screw 10 to be fixedly linked with frame side lower end front surface 501b, connector lower end 2b is affixed on longitudinal sections upper end outer surface 302c is simultaneously connect across longitudinal sections upper end 302a with frame side lower end 501a by the second screw 11, and in longitudinal sections upper end, 302a is opened There is the waist type groove 12 passed through for the second screw 11 and for avoiding the second screw 11 in the rotation of Lumbar 3.The height of waist type groove 12 12a is greater than its width 12b, and the evacuation gap of generation can make Lumbar 3 in the course of rotation, and the second screw 11 has evacuation empty Between；Specifically, connector upper and lower end 2a, 2b are respectively provided with first, second mounting hole 201a, 202b, corresponding frame side lower end Front surface 501b is equipped with the first screw hole 5a, the second screw hole 5b；It first passes through the first screw 10 and connector 2 is connected with frame side 501, Then connector lower end 2b and longitudinal sections upper end 302a, frame side lower end 501a are successively connected to one with the second screw 11 again It rises.

It further include the arc convex 13 and matched evacuation being positioned close at the upper surface 302d of longitudinal sections upper end Notch 14, arc convex 13 are rotated around evacuation notch 14, and longitudinal sections upper end outer surface 302c is equipped with one and accommodates 2 lower half of connector Partial inner cavity 15, the setting of arc convex 13 avoid notch 14 and are arranged on connector inner surface 202 in 15 bottom of chamber of inner cavity.Arc Shape protrusion 13 forms shaft, and rotation point is in longitudinal sections upper end 302a, and the upper end tilts limited extent when longitudinal sections 302 rotate, Lofty sense is not had, connector 2 will not be impacted；Lumbar 3 can orderly rotate, while 2 conduct of connector in rotation The rotation of Lumbar 3 supports, and kills two birds with one stone.The thickness of the lower half portion 55 of connector 2 is gradually thinning from top to bottom, in inner cavity 15 It is inside correspondingly provided with a slope 18, in a free state, 2 lower half portion inner surface of connector offsets with slope 18.Under connector 2 Half part is thinning to rotate slot milling to longitudinal sections 302, and can rotate to longitudinal sections 302 form limit simultaneously.

It is equipped with groove 16 in frame side lower end front surface 501b, groove 16 includes shallower upper slot 16a and deeper lower slot 16b, upper slot 16a are matched with 2 top half shape of connector, size, lower slot 16b and longitudinal sections upper end 302a shape, size Match, after longitudinal sections upper end 302a is fastened in lower slot 16b, longitudinal sections upper end outer surface 302c is concordant with upper slot 16a slot bottom.In this way Be arranged and make it possible to for the longitudinal sections 302 of Lumbar 3 and connector 2 being hidden in groove 16, conducive to lean against 1 shape integral, more Beneficial to configuring screen cloth (not shown).

As shown in fig. 7, after installation, connector outer surface 201, longitudinal sections upper end outer surface 302c and frame side front surface 501b is on the same face, so that screen cloth (not shown) does not have evagination leaning against 1, Lumbar, 3 intersection.

It is formed with side block 17 in this side of close 501 outer peripheral edge of frame side of groove 16, the side block 17 is higher by recessed Slot 16.Side block 17, which can be blocked, blocks a part for 302 upper end of longitudinal sections, reduces seam and exposes, prevents clamp hand.

It further include having strip (not shown) and screen cloth (not shown), the table before the front surface, top cross-member of frame side 501 Face and longitudinal sections 302, traversing section outer surface 301a are equipped with card slot (not shown), and the screen cloth (not shown) is by strip card In the card slot.

As shown in Figure 5,6, the present embodiment after and provide a kind of seat, including above-described back structure.

Claims (15)

1. a kind of back structure, including lean against, Lumbar, it is characterised in that: it is described to lean against including back frame and the coupled chair back Support rod, the back frame include every opposite frame side and being connected to the top cross-member of two frame sides upper end between left and right； The Lumbar is the U-shaped structure of open upper end, and the Lumbar includes traversing section and the longitudinal direction that is upwardly extended by traversing section both ends Section, longitudinal sections upper end is connected with frame side lower end by connector and longitudinal sections upper end is rotated around frame side lower end, while longitudinal Buffer gear is equipped between Duan Shangduan and frame side lower end.

2. back structure according to claim 1, it is characterised in that: the buffer gear is pressure spring or torsional spring.

3. back structure according to claim 2, it is characterised in that: the buffer gear uses pressure spring, the both ends of pressure spring It offsets respectively with longitudinal sections upper end inner surface, frame side lower end front surface.

4. back structure according to claim 3, it is characterised in that: it further include having the positioning column and cavity being arranged oppositely, The positioning column is set in one of them of longitudinal sections upper end inner surface or frame side lower end front surface, and cavity is then set to On another of longitudinal sections upper end inner surface or frame side lower end front surface；One end of pressure spring is placed in cavity, and positioning column is then It is inserted in the other end of pressure spring.

5. back structure according to claim 4, it is characterised in that: length is greater than positioning to the spring in its natural state The length of length and spring under complete compressive state of column is greater than or equal to positioning column length.

6. back structure according to claim 1, it is characterised in that: the connector is a strip connecting plate, even Fitting upper end exceeds longitudinal sections upper end upwards and is fixedly linked by the first screw and frame side lower end front surface, connector lower end It is affixed on longitudinal sections upper end outer surface and longitudinal sections upper end is passed through by the second screw and connect with frame side lower thread, in longitudinal sections Upper end is provided with the waist type groove passed through for the second screw and for avoiding the second screw in Lumbar rotation.

7. back structure according to claim 6, it is characterised in that: further include an arc convex and matched evacuation Notch, arc convex are equipped with one and accommodate connector lower half portion around evacuation notch rotation, longitudinal sections upper end outer surface Inner cavity, the arc convex are arranged in one of them in inner cavity bottom of chamber or connector inner surface, the evacuation notch It is arranged on another in inner cavity bottom of chamber or connector inner surface.

8. back structure according to claim 7, it is characterised in that: the arc convex is positioned close in longitudinal sections At the position on surface.

9. back structure according to claim 7, it is characterised in that: in frame side, lower end front surface is equipped with groove, described Groove include shallower upper slot and deeper lower slot, the upper slot is matched with connector top half shape, size, lower slot It is matched with longitudinal sections upper end shape, size, after longitudinal sections upper end is fastened in lower slot, longitudinal sections upper end outer surface and upper slot slot bottom Concordantly.

10. back structure according to claim 9, it is characterised in that: in this of the close frame side outer peripheral edge of groove Side is formed with side block, and the side block is higher by groove.

11. back structure according to claim 7, it is characterised in that: the thickness of the lower half portion of connector is from top to bottom Gradually thinning, intracavitary inside to be correspondingly provided with a slope, in a free state, connector lower half portion inner surface is supported with Slope Facies.

12. back structure according to claim 1, it is characterised in that: the longitudinal sections are the arcuate shape of lordosis.

13. back structure according to claim 1, it is characterised in that: it further include having strip and screen cloth, the table before frame side Face, top cross-member front surface and longitudinal sections, traversing section outer surface are equipped with card slot, and the screen cloth is stuck in described by strip Card slot in.

14. back structure according to claim 1, it is characterised in that: the upper end of back support bar forms two diagonally forward The headtree of extension, the headtree are connected with frame side lower end, spaced between Lumbar and back support bar.

15. a kind of seat, it is characterised in that: including such as described in any item back structures of claim 1-14.