CONVENIENTLY ADJUSTABLE SEAT BACKREST STRUCTURE

Abstract

An adjustable seat backrest structure, including a support, an adjusting component, and backrest plates; an adjusting groove extending along an up-down direction is formed at a middle part of the support; a front side of the adjusting component is connected to the backrest plates; an adjusting part is arranged on a rear side of the adjusting component; a left end and a right end of the adjusting part engage with a left side edge and a right side edge of the adjusting groove respectively so that the adjusting part is slidable up and down in the adjusting groove and being capable to be fixed at any position with respect to the adjusting groove, but not capable of moving front and back with respect to the adjusting groove.

Claims

1. An adjustable seat backrest structure, comprising: a support, an adjusting component, and backrest plates; an adjusting groove extending along an up-down direction is formed at a middle part of the support; a front side of the adjusting component is connected to the backrest plates; an adjusting part is arranged on a rear side of the adjusting component; a left end and a right end of the adjusting part engage with a left side edge and a right side edge of the adjusting groove respectively so that the adjusting part is slidable up and down in the adjusting groove and being capable to be fixed at any position with respect to the adjusting groove, but not capable of moving front and back with respect to the adjusting groove.

2. The adjustable seat backrest structure of claim 1, wherein a rotary knob is arranged on a back surface of the adjusting part; two press blocks are arranged on a left side and a right side of the rotary knob respectively; rotation of the rotary knob is capable of driving the two press blocks to slide at the left end and the right end of the adjusting part so as to removably press against the left side edge and the right side edge of the adjusting groove respectively.

3. The adjustable seat backrest structure of claim 2, wherein two clamping grooves penetrating up and down through the adjusting part are arranged at the left end and the right end of the adjusting part respectively; the left side edge and the right side edge of the adjusting groove are fitted into the clamping grooves respectively to limit the adjusting part to move front and back with respect to the adjusting groove and to allow the adjusting part to slide up and down in the adjusting groove by allowing sliding of the left side edge and the right side edge of the adjusting groove in the clamping grooves as the adjusting part slides up and down in the adjusting groove.

4. The adjustable seat backrest structure of claim 3, wherein the adjusting part comprises an adjusting main body and an adjusting back shell; the adjusting back shell covers on a rear side of the adjusting main body; the two clamping grooves are formed between a left side of the adjusting back shell and the rear side of the adjusting main body and between a right side of the adjusting back shell and the rear side of the adjusting main body respectively.

5. The adjustable seat backrest structure of claim 2, wherein the two press blocks are slidably assembled on the left end and the right end of the adjusting part respectively; two press parts are formed at outer ends of the two press blocks respectively; the press parts removably abut against the left side edge and the right side edge of the adjusting groove respectively; two arc-shaped convex surfaces are formed at inner ends of the two press blocks respectively; the rotary knob is rotatably mounted at the adjusting part, and a rotary knob main body of the rotary knob is located between the inner ends of the two press blocks; two driver parts are arranged on an outer circumference of the rotary knob main body spaced apart from each other by 180 degrees; each of the driver parts comprises a convex part and a concave part distributed adjacently along a circumferential direction of the rotary knob main body; two press blocks are connected to each other by a tension spring; the tension spring provides an elastic force to enable the inner ends of the two press blocks to abut against the driver parts respectively; when the rotary knob rotates to enable the convex parts of the two driver parts to simultaneously abut against the arc-shaped convex surfaces of the two press blocks, the press parts of the press blocks press against the left side edge and the right side edge of the adjusting groove; when the rotary knob rotates to enable the concave parts of the two driver parts to simultaneously abut against the arc-shaped convex surfaces of the two press blocks, the press parts of the two press blocks do not press against the left side edge and the right side edge of the adjusting groove.

6. The adjustable seat backrest structure of claim 5, wherein the adjusting part comprises an adjusting main body and an adjusting back shell; the adjusting back shell covers on a rear side of the adjusting main body; a mounting chamber is arranged between the adjusting back shell and the adjusting main body; the rotary knob main body of the rotary knob is rotatably mounted at a middle part of the mounting chamber, and a rotating handle exposed from a rear side of the adjusting back shell is arranged on a rear side of the rotary knob main body; the two press blocks are mounted in two sliding grooves on a left side and a right side of the mounting chamber respectively; the tension spring is located in front of the rotary knob, and two ends of the tension spring are connected to two hook parts protruding towards front sides of the two press blocks respectively.

7. The adjustable seat backrest structure of claim 6, wherein rotating grooves are formed in the mounting chamber on the rear side of the adjusting main body; rotating parts are formed at a middle part of a front side of the rotary knob main body, and the rotating parts are rotatably inserted into the rotating grooves respectively; two limiting plates spaced apart from each other by 180 degrees are arranged on outer circumferential side walls of the rotating grooves respectively; two limiting grooves spaced apart from each other by 180 degrees are formed on a circumferential area surrounding outer peripheries of the rotating parts of the rotary knob main body; the two limiting plates are located within the two limiting grooves respectively; when each of the limiting plates abuts against a first end of a corresponding limiting groove, the convex parts of the driver parts abut against the two press blocks; when each of the limiting plates abuts against a second end of the corresponding limiting groove, the concave parts of the driver parts abut against the two press blocks.

8. The adjustable seat backrest structure of claim 2, wherein a vertically extending teethed portion is arranged on each of the left side edge and the right side edge of the adjusting groove, and the teethed portion is engagable with an outer end of a corresponding press block.

9. The adjustable seat backrest structure of claim 1, wherein the support is a frame, and a middle part of the frame is provided with the adjusting groove; the support is configured to be integrally connected with a seat or detachably attached to the seat.

10. The adjustable seat backrest structure of claim 1, wherein two connecting parts are arranged on the front side of the adjusting component; the backrest plates are detachably connected with the two connecting parts respectively through elastic cantilevers; a connecting chamber is provided inside each of the two connecting parts; an inserting groove communicating with an external environment is formed on one side of the connecting chamber; a front end of a corresponding elastic cantilever is connected with a corresponding backrest plate; an inserting piece is arranged at a rear end of the corresponding elastic cantilever; the inserting piece is removably inserted into and detachably fixed in the inserting groove.

11. The adjustable seat backrest structure of claim 10, wherein a rotatable pressing plate is mounted inside the connecting chamber; one end of the pressing plate is a locking hook part; the locking hook part is located within the connecting chamber; another end of the pressing plate is a pressing part; the pressing part protrudes out of the connecting chamber; the pressing part is connected to a spring; the spring provides an elastic force to push the pressing part to bias the locking hook part to pivot at a position where the locking hook part fixes the inserting piece.

12. The adjustable seat backrest structure of claim 11, wherein the inserting piece is provided with an inserting hole; a locking block protrudes from the locking hook part; the locking block is removably inserted into the inserting hole of the inserting piece inserted into the inserting groove.

13. The adjustable seat backrest structure of claim 11, wherein a quantity of the backrest plates is two, and the two backrest plates are arranged side by side in a left-right direction; the two connecting parts are also arranged side by side in the left-right direction corresponding to the two backrest plates; the two connecting parts are arranged to a left side and to a right side of the adjusting part respectively and positioned in front of the adjusting part; each of the two connecting parts comprises a connecting main body and a connecting front cover; the connecting front cover is closed on a front side of the connecting main body; the connecting chamber is defined between the connecting front cover and the connecting main body.

14. The adjustable seat backrest structure of claim 13, wherein the connecting front cover of any one of the two connecting parts is closed at an outer side of the connecting main body of said any one of the two connecting parts which is a side far away from the connecting main body of another one of the two connecting parts; a spring groove is formed inside the connecting main body; the pressing part of the pressing plate is located on a front side yet spaced apart from said front side of the spring groove; the spring is mounted to the spring groove, and two ends of the spring abut against a bottom of the spring groove and a rear side of the pressing part respectively.

15. The adjustable seat backrest structure of claim 12, wherein a rotating shaft is arranged between the locking hook part and the pressing part of the pressing plate, and the rotating shaft is rotatably mounted within the connecting chamber; an inclined surface is formed on a side of the locking block facing an opening of the inserting groove.

16. The adjustable seat backrest structure of claim 10, wherein each of the elastic cantilevers 5 is an elastic sheet.

17. The adjustable seat backrest structure of claim 1, wherein each of the backrest plates comprises a frame plate and a flexible back cushion; a rear side of the frame plate is connected to the front side of the adjusting component; the flexible back cushion is detachably fixed on a front side of the frame plate.

18. The adjustable seat backrest structure of claim 17, wherein connecting holes are formed around the frame plate; upper and lower parts of the flexible back cushion are embedded with connecting pieces; connecting columns extending out of a rear side of the flexible back cushion are arranged on a left side and a right side of each of the connecting pieces, and each of the connecting columns is detachably inserted into a corresponding connecting hole.

19. The adjustable seat backrest structure of claim 17, wherein each of the backrest plates is provided with a vibrating motor; the frame plate has a concaved middle part, and a plurality of through holes are formed on the frame plate; the vibrating motor is fixed to a rear side of the flexible back cushion and is located within one of the through holes of the frame plate.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0044] FIG. 1 is a front perspective view of an embodiment of the present invention;

[0045] FIG. 2 is a rear perspective view of the embodiment of the present invention;

[0046] FIG. 3 is a left side view of the embodiment of the present invention;

[0047] FIG. 4 is an exploded view of the embodiment of the present invention;

[0048] FIG. 5 is a first sectional view of the embodiment of the present invention;

[0049] FIG. 6 is a second sectional view of the embodiment of the present invention;

[0050] FIG. 7 is a first exploded view of a partial structure of the embodiment of the present invention;

[0051] FIG. 8 is a second exploded view of a partial structure of the embodiment of the present invention; and

[0052] FIG. 9 is an exploded view of the backrest plates of the embodiment of the present invention.

[0053] Description of reference numerals: support 1, adjusting groove 11, side edge 111, teethed portion 112, adjusting component 2, adjusting part 21, adjusting main body 211, adjusting back shell 212, mounting chamber 213, sliding groove 214, rotating groove 215, limiting plate 216, rotary knob 22, rotary knob main body 221, driver part 222, convex part 2221, concave part 2222, rotating handle 223, rotating part 224, limiting groove 225, blocking block 2251, press block 23, press part 231, arc-shaped convex surface 232, hook part 233, clamping groove 24, tension spring 25, connecting part 26, connecting main body 261, connecting front cover 262, connecting chamber 263, inserting groove 264, spring groove 265, pressing plate 27, locking hook part 271, locking block 2711, inclined surface 2712, pressing part 272, rotating shaft 273, spring 28, backrest plate 3, frame plate 31, through hole 311, connecting hole 312, flexible back cushion 32, connecting piece 321, connecting column 322, vibrating motor 4, elastic cantilever 5, inserting piece 51, and inserting hole 511.

DETAILED DESCRIPTION OF THE INVENTION

[0054] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions according to the embodiments of the present application will be clearly and thoroughly described below with reference to the drawings of the embodiments of the present application. It is evident that the described embodiments are some but not all embodiments of the present application. Components of the embodiments of the present application generally described and illustrated in the drawings herein may be arranged and designed in various configurations.

[0055] As shown in FIGS. 1 to 4, a conveniently adjustable seat backrest structure of the present invention comprises a support 1, an adjusting component 2, and backrest plates 3.

[0056] As shown in FIGS. 2 and 4, an adjusting groove 11 extending along an up-down direction is formed at a middle part of the support 1; heights of the adjusting component 2 and the backrest plates 3 are adjustable thanks to the adjusting groove 11.

[0057] A front side of the adjusting component 2 is connected to the backrest plates 3; the backrest plates 3 are used for backing and supporting a user's back, and each of the backrest plates 3 is concaved in a middle part thereof to relieve back fatigue of the user when sitting for too long.

[0058] An adjusting part 21 is arranged on a rear side of the adjusting component 2; a left end and a right end of the adjusting part 21 engage with two side edges 111 (a left side edge and a right side edge) of the adjusting groove 11 respectively so that the adjusting part 21 is slidable up and down in the adjusting groove 11 to an arbitrary position with respect to the adjusting groove 11 as desired and being capable to be fixed to that arbitrary position with respect to the adjusting groove 11, but not capable of moving front and back with respect to the adjusting groove 11. The operation of the present invention is simple and convenient, and sliding and fixing are fast and convenient. Therefore, the up-down height adjustment of the backrest plates 3 can be achieved by using the adjusting component 2 to adapt to users of different heights, and the user's experience of backrest plates adjustment can be improved.

[0059] Specifically, a rotary knob 22 is arranged on a back surface of the adjusting part 21; two press blocks 23 are arranged on a left side and a right side of the rotary knob 22 respectively; rotation of the rotary knob 22 is capable of driving the two press blocks 23 to slide at the left end and the right end of the adjusting part 21 so as to removably press against the two side edges 111 of the adjusting groove 11.

[0060] Therefore, when the heights of the backrest plates 3 require adjustment, the rotary knob 22 is first rotated so that the two press blocks 23 do not press tightly against the two side edges 111 of the adjusting groove 11, and in this case, the adjusting component 2 can slide up and down in the adjusting groove 11 and thus drive the backrest plates 3 to slide up and down as well; after reaching a desired height, the rotary knob 22 is rotated reversely to enable the two press blocks 23 to press tightly against the two side edges 111 of the adjusting groove 11, thereby achieving positioning and fixing of the adjusting component 2 and the backrest plates 3. The operation of the present invention is simple and convenient. A relative position between the adjusting component 2 and the adjusting groove 11 can be adjusted by simply rotating the rotary knob 22; the two press blocks 23 can also press against and thus being fixed to any heights of the adjusting groove, such that sliding and fixing are fast and convenient, and the user's experience of backrest plates 3 adjustment can be improved.

[0061] As shown in FIGS. 4 and 5, in this embodiment, two clamping grooves 24 penetrating up and down through the adjusting part 21 are arranged at the left end and the right end of the adjusting part 21 respectively; the two side edges 111 of the adjusting groove 11 are fitted into the clamping grooves 24 respectively to limit the adjusting part 21 to move front and back with respect to the adjusting groove 11 and to allow the adjusting part 21 to slide up and down in the adjusting groove 11 by allowing sliding of the two side edges 111 in the clamping grooves 24 as the adjusting part 21 slides up and down in the adjusting groove 11. The clamping grooves 24 can increase sliding stability of the adjusting component 2 and prevent the adjusting component 2 from detaching from the support 1.

[0062] In this embodiment, the two press blocks 23 are slidably assembled on the left end and the right end of the adjusting part 21 respectively; two press parts 231 are formed at outer ends of the two press blocks 23 respectively; the press parts 231 removably abuts against the two side edges 111 of the adjusting groove 11 respectively; two arc-shaped convex surfaces 232 are formed at inner ends of the two press blocks 23 respectively; the press parts 231 can be made of a flexible material to abut tightly against the two side edges 111 of the adjusting groove 11, thereby improving the effect of tight fitting.

[0063] The rotary knob 22 is rotatably mounted at the adjusting part 21, and a rotary knob main body 221 of the rotary knob 22 is located between the inner ends of the two press blocks 23; two driver parts 222 are arranged on an outer circumference of the rotary knob main body 221 spaced apart from each other by 180 degrees; each of the driver parts 222 comprises a convex part 2221 and a concave part 2222 distributed adjacently along a circumferential direction of the rotary knob main body 221; two press blocks 23 are connected to each other by a tension spring 25; the tension spring 25 provides an elastic force to enable the inner ends of the press blocks 23 to abut against the driver parts 222 respectively. Therefore, when the rotary knob 22 rotates to enable the convex parts 2221 of the two driver parts 222 to simultaneously abut against the arc-shaped convex surfaces 232 of the two press blocks 23, the press parts 231 of the press blocks 23 press tightly against the two side edges 111 of the adjusting groove 11; when the rotary knob 22 rotates to enable the concave parts 2222 of the two driver parts 222 to simultaneously abut against the arc-shaped convex surfaces 232 of the two press blocks 23, the press parts 231 of the two press blocks 23 do not press against the two side edges 111 of the adjusting groove 11.

[0064] The tension spring 25 provides an elastic force to bias the two press blocks 23 to be biased towards each other, and the convex parts 2221 of the two driver parts 222 of the rotary knob 22 are also located between the two press blocks 23 to provide a counter supporting force, such that the two press blocks 23 can press tightly against the two side edges 111 of the adjusting groove 11 so that the adjusting component 2 will not drop downwardly in the adjusting groove 11 due to gravity.

[0065] The arc-shaped convex surfaces 232 of the two press blocks 23 facilitate sliding movements of the two press blocks 23 driven by the driver part 222 in a way that rotational movement of the rotary knob 22 can be transformed into left-right sliding movements of the two press blocks 23 through the convex parts 2221 and the concave parts 2222.

[0066] Referring to FIGS. 7 and 8, the adjusting part 21 comprises an adjusting main body 211 and an adjusting back shell 212; the adjusting back shell 212 covers on a rear side of the adjusting main body 211; the adjusting main body 211 and the adjusting back shell 212 can be fixed through screws.

[0067] A mounting chamber 213 is arranged between the adjusting back shell 212 and the adjusting main body 211; the two clamping grooves 24 are formed between a left side of the adjusting back shell 212 and the rear side of the adjusting main body 211 and between a right side of the adjusting back shell 212 and the rear side of the adjusting main body 211 respectively.

[0068] The rotary knob main body 221 of the rotary knob 22 is rotatably mounted at a middle part of the mounting chamber 213, and a rotating handle 223 exposed from a rear side of the adjusting back shell 212 is arranged on a rear side of the rotary knob main body 221 for the user to conveniently hold the rotating handle 223 to rotate the rotary knob 22.

[0069] The two press blocks 23 are mounted in two sliding grooves 214 on a left side and a right side of the mounting chamber 213 respectively; the tension spring 25 is located in front of the rotary knob 22, and two ends of the tension spring 25 are connected to two hook parts 233 protruding towards front sides of the two press blocks 23 respectively.

[0070] Rotating grooves 215 can be formed in the mounting chamber 213 on the rear side of the adjusting main body 211; rotating parts 224 are formed at a middle part of a front side of the rotary knob main body 221, and the rotating parts 224 are rotatably inserted into the rotating grooves 215 respectively; two limiting plates 216 spaced apart from each other by 180 degrees are arranged on outer circumferential side walls of the rotating grooves 215 respectively; two limiting grooves 225 spaced apart from each other by 180 degrees are formed on a circumferential area surrounding outer peripheries of the rotating parts 224 of the rotary knob main body 221; the two limiting plates 216 are located within the two limiting grooves 225 respectively. In this embodiment, each of the limiting grooves 225 is formed between two blocking blocks 2251 protruded from an outer periphery of a front side of the rotary knob 22.

[0071] When each of the limiting plates 216 abuts against a first of the two blocking blocks 2251 disposed along a circumferential direction of a corresponding limiting groove 225, the convex parts 2221 of the driver parts 222 abut against the two press blocks 23 so that the two press parts 231 abut against the two side edges 111 of the adjusting groove 11; when each of the limiting plates 216 abuts against a second of the two blocking blocks 2251 disposed along the circumferential direction of a corresponding limiting groove 225, the concave parts 2222 of the driver parts 22 abut against the two press blocks 23 so that the two press parts 231 no longer abut against the two side edges 111 of the adjusting groove 11; in other words, when the rotary knob 22 rotates, excessive rotation of the rotary knob 22 can be prevented by the limiting plates 216 which limit the rotary knob 22 to rotate within a range defined by the two limiting grooves 225, thereby ensuring that each of the driver parts 222 and the corresponding press block 23 are in contact either through the corresponding convex part 2221 or the corresponding concave part 2222. For example, FIG. 5 shows a state where the convex parts 2221 of the driver parts 222 abut against the two press blocks 23, and the limiting plates 216 abut against first blocking blocks of the limiting grooves 225 (which are the blocking blocks 2251 which the limiting plates 216 abut when the rotatory knob 22 is rotated clockwise); when the rotary knob 22 is controlled to rotate counterclockwise so that the concave parts 2222 of the driver parts 222 abut against the two press blocks 23, the limiting plates 216 will then abut against second blocking blocks of the limiting grooves 225 (which are the blocking blocks 2251 which the limiting plates 216 abut when the rotatory knob 22 is rotated counterclockwise).

[0072] In this embodiment, a vertically extending teethed portion 112 is arranged on each of the two side edges 111 of the adjusting groove 11, and the teethed portion 112 is engagable with the outer end of a corresponding press block 23, thereby improving the fixing and positioning effect of the adjusting component 2 in the adjusting groove 11.

[0073] In this embodiment, the support 1 is an independent frame, and the middle part of the frame shape is provided with the adjusting groove 11; the support 1 can be detachably attached to a backrest of a seat by using a binding band (not shown).

[0074] Alternatively, the support 1 can also be designed to be integral with the seat, in other words, the seat backrest structure of the present invention can be directly used as the backrest of the seat.

[0075] As shown in FIGS. 2, 3, and 9, each of the backrest plates 3 can be provided with a vibrating motor 4. The vibrating motor 4 can be used to achieve massage function of each backrest plate 3 to massage the back of the user.

[0076] Specifically, in this embodiment, each of the backrest plates 3 comprises a frame plate 31 and a flexible back cushion 32.

[0077] The frame plate 31 is substantially a structure with a concaved middle part, and a plurality of through holes 311 are formed on the frame plate 31 to reduce the weight of the frame plate 31 while maintaining the structural strength of the frame plate 31.

[0078] A rear side of the frame plate 31 is connected to an elastic cantilever 5.

[0079] The flexible back cushion 32 is detachably fixed on a front side of the frame plate 31.

[0080] Connecting holes 312 are formed around the frame plate 31; upper and lower parts of the flexible back cushion 32 are embedded with connecting pieces 321; connecting columns 322 extending out of a rear side of the flexible back cushion 32 are arranged on a left side and a right side of each of the connecting pieces 321, and each of the connecting columns 322 is detachably inserted into a corresponding connecting hole 312.

[0081] In this embodiment, an upper-left corner, a lower-left corner, an upper-right corner, and a lower-right corner of the frame plate 31 are each provided with a respective connecting hole 312, and the left side and the right side of each of the connecting pieces 321 are each provided with a respective connecting columns 322. Accordingly, installation and detachment of the flexible back cushion 32 are achieved, thereby facilitating replacement and cleaning.

[0082] The vibrating motor 4 is fixed to the rear side of the flexible back cushion 32 and is located within one of the through holes 311 of the frame plate 31.

[0083] Therefore, the vibrating motor 4 is directly fixed on the flexible back cushion 32, and so a better massage effect can be achieved. The flexible back cushion 32 can be a silicone cushion or the like.

[0084] As shown in FIGS. 1, 2, and 9, in this embodiment, a quantity of the backrest plates 3 can be two, and the two backrest plates 3 are arranged symmetrically left and right. However, a specific quantity of the backrest plates 3 shall not be limited to two.

[0085] The backrest plates 3 on both left and right sides can be detachably connected to the front side of the adjusting component 2 through corresponding elastic cantilevers 5 respectively. In this embodiment, for example, each of the elastic cantilevers 5 is a U-shaped elastic sheet.

[0086] In this embodiment, two connecting parts 26 arranged symmetrically are arranged on the front side of the adjusting component 2; the two connecting parts 26 can be arranged to a left side and to a right side of the adjusting part 21 respectively and positioned in front of the adjusting part 21.

[0087] The elastic cantilevers 5 and the connecting parts 26 can be detachably connected by screws, or can be quickly disassembled and assembled by using the following structure: referring to FIGS. 7 and 8, each of the connecting parts 26 comprises a connecting main body 261 and a connecting front cover 262, the connecting front cover 262 is closed on a front side of the connecting main body 261, and the connecting main body 261 and the connecting front cover 262 can be fixed through screws.

[0088] A connecting chamber 263 is defined between the connecting front cover 262 and the connecting main body 261; an inserting groove 264 communicating with an external environment is formed on one side of the connecting chamber 263; a front end of a corresponding elastic cantilever 5 and a corresponding backrest plate 3 can be connected and fixed through screws; an inserting piece 51 is arranged at a rear end of the corresponding elastic cantilever 5, the inserting piece 51 is provided with an inserting hole 511, and the inserting piece 51 is inserted into the inserting groove 264.

[0089] A rotatable pressing plate 27 is mounted inside the connecting chamber 263; one end of the pressing plate 27 is a locking hook part 271; the locking hook part 271 is located within the connecting chamber 263; a locking block 2711 protrudes from the locking hook part 271; another end of the pressing plate 27 is a pressing part 272; the pressing part 272 protrudes out of the connecting chamber 263; the pressing part 272 is connected to a spring 28, and the spring 28 pushes the pressing part 272 to bias the locking hook part 271 to pivot at a position where the locking block 2711 is inserted into the inserting hole 511 of the inserting piece 51 inserted into the inserting groove 264.

[0090] Therefore, in this embodiment, each of the backrest plates 3 can achieve quick disassembly and assembly with a corresponding connecting part 26 of the adjusting component 2 through the inserting piece 51 of a corresponding elastic cantilever 5, thereby facilitating the replacement, maintenance, and the like of the backrest plates 3.

[0091] Specifically, the connecting front cover 262 is closed at an outer side of the connecting main body 261 which is a side far away from a middle part of the adjusting component 2, and a spring groove 265 is formed inside the connecting main body 261; the pressing part 272 of the pressing plate 27 is located on a front side yet spaced apart from said front side of the spring groove 265; the spring 28 is mounted to the spring groove 265, and two ends of the spring 28 abut against a bottom of the spring groove 265 and a rear side of the pressing part 272 respectively. The spring 28 pushes the pressing part 272 of the pressing plate 27 forward, such that the locking hook part 271 is pivoted backward to firmly hold the inserting piece 51 within the inserting groove 264; when the backrest plates 3 need to be detached, it is only required to press the pressing part 272 to compress the spring 28 to pivot the pressing plate 27 towards an opposite direction, such that the locking block 2711 of the locking hook part 271 is separated from the inserting hole 511 of the inserting piece 51; accordingly, the inserting piece 51 can be pulled out from the inserting groove 264 to achieve separation between a corresponding backrest plate 3 and a corresponding connecting part 26.

[0092] In this embodiment, a rotating shaft 273 is arranged between the locking hook part 271 and the pressing part 272 of the pressing plate 27, and the rotating shaft 273 is rotatably mounted within the connecting chamber 263 so that the pressing plate 27 is pivotable.

[0093] Further, in this embodiment, an inclined surface 2712 can be formed on a side of the locking block 2711 facing an opening of the inserting groove 264. Therefore, as the inserting piece 51 is in contact with the locking block 2711 during insertion into the inserting groove 264, the inserting piece 51 can be conveniently inserted into the inserting groove 264 by conveniently lifting up the locking hook part 271 through the inclined surface 2712, and then the locking block 2711 is quickly positioned and inserted into the inserting hole 511 of the inserting piece 51 due to elastic force of the spring 28, thereby achieving quick installation.