KR102505888B1 - Backlest with lumbar support and chair with the same - Google Patents

Abstract

The present invention relates to a backrest equipped with a lumbar support and a chair having the same applied thereto, the backrest comprising: a frame formed to have a quadrangular frame shape; and the lumbar support mounted on the frame such that the degree of protrusion and the height can be controlled. The lumbar support comprises: an upper coupling part coupled to an upper frame provided in the frame; a lower coupling part coupled to a lower frame; and a lumbar support part connecting the upper coupling part to the lower coupling part and elastically supporting a user's waist region. The lumbar support part is elastically deformable to correspond to a change in the user's posture, and thus the lumbar support can be formed to have a shape corresponding to the user's waist region to elastically support the user's waist region, and the degree of protrusion and height of the lumbar support can be controlled according to a change in the user's posture.

Description

Backrest with lumbar support and chair to which it is applied {BACKLEST WITH LUMBAR SUPPORT AND CHAIR WITH THE SAME}

The present invention relates to a chair, and more particularly, to a backrest having a lumbar support for supporting a user's waist and a chair to which the backrest is applied.

In general, a chair includes a seat, legs, and a backrest.

The backrest is a part that supports from the waist to the back, shoulders, and neck, and is manufactured by applying various shapes and functions by applying ergonomics.

Such a backrest is usually manufactured by attaching a plate material to the inside of the frame and covering the outer surface with a seat made of cloth or leather.

Recently, a lumbar support is installed in the backrest to relieve tension in the lumbar region and reduce the burden on the spine.

On the other hand, a function of adjusting the height of the lumbar support and the forward and backward position protruding toward the user's waist in order to give the user a comfortable sitting feeling as each user has a different sitting height and waist shape. this is being applied.

For example, the present applicant disclosed a technology for adjusting the degree of protrusion of a lumbar support applied to a chair in a number of Patent Documents 1 and 2 below, filed an application, and received registration.

Patent Document 1 includes a back frame for supporting the user's waist and back or a bracket coupled to the seat and a lumbar support fixed by the bracket and supporting the user's waist, and the lumbar support is the user's waist A pedestal for supporting the pedestal, a moving means for adjusting the height of the pedestal by being coupled to the rear side of the bracket and moving up and down along the movement space formed in the bracket, and a through-hole formed in the moving means to be coupled with the pedestal and protruding degree of the pedestal A configuration of a backrest for a chair including an adjusting means for adjusting the is described.

Patent Document 2 includes a frame formed in a rectangular frame shape, a seat portion coupled to the front of the frame, and an adjusting portion adjusting the degree of protrusion of the seat portion to correspond to the shape of the user's waist, and the adjusting portion is rotatably coupled to one side of the frame. A lever, a gear member that converts the rotational motion of the lever in the orthogonal direction, a lifting member that moves up and down by the rotational movement of the gear member, and a rotating member that moves up and down by rotating the lifting member by the rotational movement of the gear member. A configuration of a backrest for a chair is described.

However, Patent Document 1 adjusts the height of the pedestal by moving the moving means in the vertical direction, and easily adjusts the degree of protrusion of the lumbar support using the adjusting means, so that the number of parts constituting the backrest increases and the structure becomes complicated, There was a problem that the working time increased and the production cost increased.

In order to solve this problem, Patent Document 2 removes the lumbar support and adjusts the protruding degree of the seat by moving the elevating member using a gear member.

However, Patent Document 2 has a problem that is inconvenient to operate when adjusting the protruding degree of the seat portion, as it must be rotated by applying force to the lever connected to one side of the gear member.

Therefore, while adjusting the protrusion degree and height of the lumbar support according to the user's physical condition, development of a technology that can be adjusted with simple manipulation, improves workability during manufacturing work, and reduces manufacturing cost by simplifying the structure this is being requested

Republic of Korea Patent Registration No. 10-1174458 (published on August 23, 2012) Republic of Korea Patent Registration No. 10-1468703 (Announced on December 5, 2014)

An object of the present invention is to solve the above problems, and to provide a backrest having a lumbar support that can comfortably support a user's waist and a chair to which the same is applied.

Another object of the present invention is to provide a backrest with a lumbar support capable of adjusting the height and protrusion of the lumbar support according to a change in a user's posture, and a chair to which the lumbar support is applied.

Another object of the present invention is to provide a backrest with a lumbar support and a chair to which the lumbar support is applied, in which the height and protrusion of the lumbar support can be adjusted with a simple operation and the structure can be simplified.

In order to achieve the above object, a backrest with a lumbar support according to the present invention includes a frame formed in a square frame shape, and a lumbar support mounted to the frame to be able to adjust the degree of protrusion and height. The lumbar support includes an upper coupling portion coupled to an upper frame provided in the frame, a lower coupling portion coupled to the lower frame, and a lumbar support portion connecting the upper coupling portion and the lower coupling portion and elastically supporting a waist of a user, , The lumbar support is characterized in that it is provided to be elastically deformable so as to correspond to a change in the user's posture.

In addition, in order to achieve the above object, a chair to which a backrest having a lumbar support according to the present invention is applied has a leg portion, a seat portion connected to the upper side of the leg portion so that a user can sit on it, and a rear portion of the seat portion. It is characterized in that it includes a backrest connected and to which the lumbar support is installed, and the degree of protrusion and height of the lumbar support are adjustable.

As described above, according to the backrest provided with the lumbar support and the chair to which the lumbar support according to the present invention is applied, the lumbar support is formed in a shape corresponding to the waist of the user and elastically supported, and the lumbar support is provided according to the change in the user's posture. The effect of being able to adjust the degree and height of the protrusion is obtained.

Accordingly, according to the present invention, by deforming the lumbar support according to the user's physical condition and maintaining an appropriate posture, an effect of providing comfort and preventing back pain due to improper posture is obtained.

In addition, according to the present invention, the shape of the lumbar support can be changed with a simple operation, and the structure of the lumbar support and the height adjustment unit is simplified to improve workability during manufacturing work and reduce manufacturing costs. .

1 is a perspective view of a chair to which a backrest equipped with a lumbar support according to a preferred embodiment of the present invention is applied;
Figure 2 is a perspective view of the backrest shown in Figure 1 from another angle;
3 is an exploded perspective view of the backrest shown in FIG. 2;
Figure 4 is a rear view of the lumbar support shown in Figure 3;
5 is a front view of the support shown in FIG. 3;
6 and 7 are operation states of the backrest having a lumbar support according to a preferred embodiment of the present invention, respectively.

Hereinafter, a backrest provided with a lumbar support and a chair to which it is applied according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

In this specification, the direction in which the backrest is installed around the seat is referred to as 'the rear of the chair', and the opposite direction is referred to as the 'front of the chair'.

Accordingly, the side of the backrest where the user's waist and back come into contact is referred to as the 'front side of the backrest', and the opposite side is referred to as the 'rear side of the backrest'.

In the present specification, a part of the backrest that supports the user's waist is referred to as a 'lumbar support'.

1 is a perspective view of a chair to which a backrest having a lumbar support according to a preferred embodiment of the present invention is applied.

Hereinafter, terms indicating directions such as 'left', 'right', 'front', 'rear', 'upper' and 'downer' are defined as indicating each direction based on the state shown in each drawing. do.

As shown in FIG. 1, a chair 10 with a backrest equipped with a lumbar support according to a preferred embodiment of the present invention is connected to a leg part 11 to which a plurality of wheels are attached and an upper side of the leg part 11. It may include a seat part 12 for allowing a user to sit down and a backrest 13 connected to the rear side of the seat part 12 and having a lumbar support 20 installed thereon.

Armrests 14 may be mounted on both sides of the seat 12 or the backrest 13 to support the arms of the user.

In addition, a headrest 15 may be installed at an upper end of the backrest 13.

The backrest 13 may include a frame 16 formed in a substantially rectangular shape and a seat 17 installed on the front surface of the frame 16 or in an internal space to support the user's waist and back.

The frame 16 may be formed in a curved shape with central portions of both ends protruding forward to correspond to the user's back and waist.

The seat 17 may be made of cloth or leather, or may be made in a mesh shape.

Next, with reference to FIGS. 1 to 5, a configuration of a backrest having a lumbar support according to a preferred embodiment of the present invention will be described in detail.

FIG. 2 is a perspective view of the backrest shown in FIG. 1 from another angle, FIG. 3 is an exploded perspective view of the backrest shown in FIG. 2, FIG. 4 is a rear view of the lumbar support shown in FIG. 3, and FIG. It is a front view of the support shown in 3.

The backrest 13 provided with the lumbar support 30 according to a preferred embodiment of the present invention includes a frame 16 formed in a substantially rectangular frame shape, as shown in FIGS. An upper frame 21 and a lower frame 22 supporting the lumbar support 30 may be installed between the top and bottom of the ). The upper frame 21 and the lower frame 22 may be formed side by side in a horizontal direction at positions spaced apart from each other by a preset interval.

Therefore, the lumbar support 30 may be installed between the upper frame 21 and the lower frame 22 to be adjustable in height and protrusion.

In addition, the lumbar support 30 includes an upper coupling portion 40 coupled to the upper frame 21, a lower coupling portion 50 coupled to the lower frame 22, and an upper coupling portion 40 and a lower coupling portion 50. It may include a lumbar support 60 that connects and elastically supports the user's waist. Here, the lumbar support unit 60 may be elastically deformable so as to correspond to the user's waist.

The upper coupling part 40 may be rotatably coupled around the support shaft 41 coupled to the central portion of the upper frame 21 .

To this end, the upper coupling portion 40 protrudes upward from the top of the lumbar support portion 60, and is coupled to the coupling block 211 coupled to the center of the upper frame 21 by a support shaft 41 that is coupled through. It may be rotatably coupled with the upper frame 21 .

The lumbar support unit 60 may include a plurality of support plates 61 corresponding to the shape of the user's waist, for example, each lumbar vertebrae, and a connecting member 62 that elastically connects the plurality of support plates 61 to each other.

The lumbar support portion 60 may be manufactured using a synthetic resin material so as to enable elastic deformation according to a change in posture while in contact with the user's waist.

Each support plate 61 may be formed in a substantially oval or polygonal plate shape extending left and right when viewed from the front to correspond to a shape of a waist region including a user's lumbar spine. In addition, each support plate 61 may be formed in a curved shape with both ends protruding forward compared to the central portion so as to cover the user's waist.

The connecting member 62 may be formed in a convexly protruding shape from the rear surface of each support plate 61 toward the rear so that the cross section is approximately '⊃'.

So, each support plate 61 protrudes forward while each support plate 610 and the connection member 62 protrude toward the front during the lifting operation of the lower coupling part 60 by the height adjusting unit 70 to be described below. The degree and overall height can be adjusted.

That is, when the lower coupling part 60 is coupled to the lowermost end of the lower frame 22, the lower end of the lumbar support 60 moves downward to near the lowermost end of the lower frame 22. At this time, the degree of protrusion of the lumbar support portion 60 forward becomes the smallest state.

On the other hand, when the lower coupling part 60 moves upward along the support part 23 of the lower frame 22, the degree of forward protrusion of the lumbar support part 60 gradually increases.

In this way, when the lower coupling part 60 is lifted, the lumbar support 30 is deformed so that the height of the most forward protruding portion rises and the degree of forward protrusion increases.

The lower coupling part 50 may be coupled to the lower frame 22 in a height-adjustable manner.

To this end, a height adjusting portion 70 is provided at the lower coupling portion 50, and a support portion 23 supporting the lower end of the lumbar support 60 may protrude upward from the lower frame 22.

As shown in FIGS. 3 and 5 , a rotating member 24 may be installed on the front of the support 23 . The rotating member 24 may be rotated about the fixed shaft 25 in a state in which it is fixed by the fixed shaft 25 coupled to the support part 23 through the lower end in the front-rear direction. A locking protrusion 26 sequentially caught in a plurality of height adjusting grooves 722 formed in the elevating plate 72 provided in the height adjusting unit 70 may protrude from the front surface of the upper end of the rotating member 24 .

And on both sides of the rotating member 24, for example, on both sides of the upper end, a pair of elastic members 27 providing elastic force so as to maintain the rotating member 24 in its original position, that is, a state vertically disposed along the vertical direction. can be installed

A pair of elastic members 27 may be installed on both sides of the rotating member 24 as a center. So, the inner end of each elastic member 27 is connected to both sides of the upper end of the rotating member 24, and the outer end of each elastic member 27 can be supported by support ribs formed on both sides of the support part 23.

Therefore, when the lifting plate 72 moves upward, the rotating member 24 can rotate so that the locking protrusions 26 are sequentially coupled to the plurality of height adjusting grooves 722 to be caught or separated. In addition, the rotation member 24 may return to its original position by the elastic force provided from the pair of elastic members 27 and remain coupled to one of the height adjustment grooves 722 .

As shown in FIGS. 2 and 3 , the lower coupling part 50 is rotatably coupled around the rotation shaft 51 installed through the front side of the elevating member 73 provided in the height adjusting unit 70. It can be.

As shown in FIGS. 2 to 5 , the height adjustment unit 70 is capable of lifting and lowering the coupling plate portion 71 coupled to the front surface of the support portion 23 and the lifting space 711 formed inside the coupling plate portion 71. It may include an elevating plate 72 and an elevating member 73 coupled to the front surface of the elevating plate 72 and connected to the lower coupling part 50 by a rotation shaft 51.

The elevating member 73 is formed in a substantially plate shape, and a pair of shaft support units 731 coupled to the rotating shaft 51 may be provided on both sides of the front surface of the elevating member 73 . In addition, a pair of control levers 732 may be formed to extend long toward both sides of the pair of shaft support portions 731 so that the user can manually adjust the height thereof.

The coupling plate portion 71 may be formed in a substantially rectangular frame shape so that an elevating space 711 is formed in the central portion.

The elevating plate 72 can slide in the vertical direction by the elevating operation of the elevating member 73 in a state of being coupled to the elevating space 711 formed in the coupling plate unit 71 .

A plurality of height adjustment grooves 722 may be formed side by side in the vertical direction on the rear surface of the elevating plate 72 .

That is, an adjustment member 721 protruding convexly rearward may be provided on the rear surface of the elevating plate 72, and a plurality of height adjustment grooves 722 may be formed on one side of the adjustment member 721. For example, each height adjustment groove 722 may be formed on the left side of the adjusting member 721 inclined toward the lower left side.

And, of both sides of the adjusting member 721, on the side where the plurality of height adjustment grooves 722 are formed, that is, on the left side, the elevating plate 72 engages and releases the locking protrusion 26 of the rotating member 24 while lifting. To do so, an elevated space 723 communicating with each height adjustment groove 722 may be formed.

In addition, a descending space 724 may be formed on the right side of the adjusting member 721 , in which the elevating plate 72 moves downward to the lower end of the support 23 in a state in which the elevating plate 72 rises to the upper end of the support 23 . In addition, at the upper and lower ends of the adjusting member 721, the protrusions 26 are moved from the rising space 723 to the lowering space 724 or from the lowering space 724 to the rising space 723. First and second moving spaces 725 and 726 may be formed.

That is, an ascending space 723 and a plurality of height adjusting grooves 723 are formed in communication with the adjusting member 721 on the left side of the adjusting member 721, and a descending space 724 is formed on the right side of the adjusting member 721. is formed, and first and second moving spaces 725 and 726 may be formed in communication with the ascending space 723 and the descending space 724 at the upper and lower ends of the adjusting member 721, respectively.

Accordingly, the locking protrusion 26 rotates to be disposed in the lifting space 723 when the lifting plate 72 is lifted. So, the protrusion 26 moves along the direction of the arrow A shown in FIG. 4 . That is, the protrusion 26 is relatively lowered as the elevating plate 72 moves upward, and the height of the upper end of the plurality of height adjusting grooves 722 is increased by the elastic force provided by the pair of elastic members 27. From the adjustment groove 722 to the height adjustment groove 722 at the bottom, it can be sequentially coupled and hung.

And when the elevating plate 72 sequentially ascends to the upper end of the support part 23 and then descends to the lower end of the support part 23, the holding protrusion 26 moves along the direction of the arrow B shown in FIG. 4 to the adjusting member 721 rises from the bottom to the top of That is, the protrusion 26 may rise through the second moving space 726, the lowering space 724, and the first moving space 725 and return to the top of the rising space 723 again.

On the other hand, as shown in FIG. 4, a plurality of pairs of locking grooves 712 are formed at both ends of the rear surface of the coupling plate unit 71, and at both ends of the lifting plate 72, respectively, during the lifting operation of the lifting plate 72. , A pair of locking pieces 727 sequentially caught in the plurality of locking grooves 712 may be formed.

Each locking groove 712 is formed concavely toward the outside on the inner surface of both side walls of the coupling plate portion 71 forming the lifting space 711, and each locking piece 727 extends from the outer surface of the lifting plate 72 to the inside and outside. It can be formed to be elastically deformable in the left and right direction, that is, inside and outside of the lifting plate 72 by the slit bent downward.

For example, the locking groove 712 is provided in three pairs to correspond to the number of height adjustment grooves 722, and the front end of each locking piece 727 has a locking protrusion 728 to be hooked on each locking groove 712. may protrude.

In this way, as the locking groove 712 and the locking piece 727 are formed on both sides of the coupling plate 71 and the lifting plate 72, respectively, the lifting plate 72 has a plurality of stages during the lifting operation, for example, the first The height is adjusted from one stage to a third stage, and may be fixed to each stage.

In addition, the lifting plate 72 moves each locking piece 727 inward when a force greater than that of the locking protrusion 728 of each locking piece 727 is applied upward or downward to each locking groove 712. It can move upward or downward while being elastically deformed.

Of course, the present invention is not necessarily limited to this, and the number of the locking groove 712 and the locking piece 727 and the number of height adjustment grooves 7 are variously changed to increase the height of the lifting plate to 2 or 4 steps or more. It can be changed to adjust to the stage.

As described above, according to the present invention, the lumbar support is formed in a shape corresponding to the user's waist, and the degree of protrusion and height of the lumbar support can be adjusted according to changes in posture of the waist.

Next, with reference to FIGS. 6 and 7 , a backrest having a lumbar support according to a preferred embodiment of the present invention and a coupling relationship and operation method of a chair to which the backrest is applied will be described in detail.

6 and 7 are operational state diagrams of a backrest having a lumbar support according to a preferred embodiment of the present invention, respectively.

6 shows a state in which the protrusion of the lumbar support is the smallest, and FIG. 7 shows a state in which the protrusion of the lumbar support is the largest.

First, in the state where the upper and lower frames 21 and 22 are formed on the frame 16 of the backrest 13, the operator attaches the upper coupling part of the lumbar support 30 to the upper frame 21 and the lower frame 22, respectively ( 40) and the lower coupling part 50 are coupled.

At this time, the upper coupling part 40 is rotatably coupled to the coupling block 211 by the support shaft 41, and the coupling block 211 is fixed while being coupled to the upper frame 21 by fastening bolts. .

And, the height adjustment unit 70 connected to the lower coupling unit 50 is coupled to the support unit 23 formed on the lower frame 22 . At this time, the elevating member 73 of the height adjusting unit 70 is rotatably coupled to the lower coupling part 50 by the rotating shaft 732 .

Then, in a state where the lifting plate 72 is placed inside the lifting space 711 of the coupling plate portion 71 so that the lifting operation is possible, the coupling plate portion 71 and the support portion 23 are coupled by fastening bolts.

Subsequently, a bolt is fastened through the elevating member 73 to couple the elevating member 73 and the elevating plate 72 .

Then, the degree and height of the lumbar support 60 provided between the upper coupling portion 40 and the lower coupling portion 50 may be adjusted forward by the lifting operation of the height adjusting unit 70 .

That is, as shown in FIG. 6, the lumbar support unit 60 protrudes forward minimally when the elevation member 73 and the elevation plate 72 of the height adjusting unit 70 are disposed at the lowermost end of the support unit 23. It becomes regulated as much as possible.

At this time, the height of the central portion protruding forward from the lumbar support 60 is also adjusted to the lowest position.

Here, the locking protrusion 26 of the rotation member 24 provided on the support part 23 is disposed in the uppermost height adjustment groove 722 among the plurality of height adjustment grooves 722 formed on the elevating plate 72, It may be disposed in the first moving space 725 above the adjusting member 721 .

On the other hand, when the user presses or pulls the control lever 732 provided on the height adjusting unit 70 upward, the elevating member 73 and the elevating plate 72 rise.

Then, the locking protrusion 26 rotates so as to be sequentially engaged and released from the plurality of height adjustment grooves 722 formed in the elevating plate 72 . At this time, the locking protrusion 26 returns to its original position, that is, a state disposed in the vertical direction, by the elastic force provided from the pair of elastic members 27 installed on both sides of the rotating member 24.

So, as the lumbar support 60 is maintained in a state in which the protrusion 26 is coupled to any one height adjustment groove 722, the corresponding height and protrusion are fixed.

On the other hand, when the elevating plate 72 of the lumbar support unit 60 is raised to the top of the support unit 23, as shown in FIG. 7, the degree of forward protrusion becomes maximum. At this time, the most protruding part forward from the lumbar support 60, that is, the central part is higher than the height of the central part shown in FIG.

Through the process as described above, the present invention can form the lumbar support in a shape corresponding to the user's waist, and adjust the degree of protrusion and height of the lumbar support according to changes in posture of the waist.

Accordingly, the present invention can provide comfort and prevent back pain due to improper posture by modifying the lumbar support according to the user's physical condition and maintaining an appropriate posture.

In addition, the present invention can change the shape of the lumbar support with a simple operation, and simplify the structure of the lumbar support and the height adjusting unit to improve workability during manufacturing operations and reduce manufacturing costs.

Although the invention made by the present inventors has been specifically described according to the above embodiments, the present invention is not limited to the above embodiments, and various changes can be made without departing from the gist of the present invention.

That is, in the above embodiment, the configuration of the chair has been described with reference to FIG. 1, but the present invention is not necessarily limited thereto.

For example, the present invention may be modified to be applicable not only to legs and seats, but also to chairs having various shapes and structures in which armrests and headrests are removed or modified.

The present invention forms a lumbar support in a shape corresponding to the user's waist, supports it elastically, and adjusts the degree of protrusion and height of the lumbar support according to the change in the user's posture. applies to

10: chair 11: leg
12: seat portion 13: backrest
14: armrest 15: headrest
16: frame 17: sheet
21: upper frame 211: coupling block
22: lower frame
23: support 24: rotating member
25: fixed axis 26: stumbling block
27: elastic member
30: lumbar support
40: upper coupling part 41: support shaft
50: lower coupling part 51: rotation shaft
60: lumbar support
61: support plate 62: connecting member
70: height adjustment unit
71: coupling plate 711: lifting space
712: control groove
72: lifting plate 721: adjusting member
722: height adjustment groove 723: rising space
724: descending space 725,726: first and second moving spaces
727: obstacle part 728: obstacle part
73: lifting member 731: shaft support
732: control lever

Claims (7)

A frame formed in a rectangular frame shape;
Including a lumbar support that is mounted to the frame to be able to adjust the degree of protrusion and height,
The lumbar support is an upper coupling portion coupled to an upper frame provided on the frame;
A lower coupling part coupled to the lower frame and
A lumbar support portion connecting the upper coupling portion and the lower coupling portion and elastically supporting a user's waist,
The lumbar support is provided to be elastically deformable to correspond to a change in the user's posture,
The lower coupling portion is provided with a height adjustment unit,
A support portion supporting the lower end of the lumbar support is formed on the lower frame,
The height adjustment unit coupling plate portion coupled to the support portion,
An elevating plate installed to enable an elevating operation in an elevating space formed inside the coupling plate unit, and
A backrest with a lumbar support, characterized in that it comprises an elevating member coupled to the front surface of the elevating plate and connected to the lower coupling portion by a rotating shaft. According to claim 1,
The lumbar support unit includes a plurality of support plates corresponding to the shape of the user's waist;
Includes a connecting member that elastically connects between the plurality of support plates,
The plurality of support plates are each formed in a long plate shape to correspond to the shape of the waist region including the user's lumbar spine, and are provided with a lumbar support, characterized in that formed in a curved shape to surround the user's waist region back of a chair. delete According to claim 1,
The support portion includes a rotating member that rotates around the lower end;
A pair of elastic members connected to both sides of the rotating member to provide elastic force to return the rotating member to its original position are installed,
The rotation member is provided with a backrest with a lumbar support, characterized in that the locking protrusions are formed which are sequentially coupled to the plurality of height adjustment grooves formed on the elevating plate to be engaged or released. According to claim 4,
An adjustment member is formed on the elevating plate toward the support portion,
On one side of the adjusting member, the plurality of height adjusting grooves are formed side by side along the vertical direction,
A backrest with a lumbar support, characterized in that each height adjustment groove is formed inclined toward one side downward. According to claim 4,
A plurality of pairs of locking grooves are formed at both ends of the coupling plate portion, respectively,
A backrest with a lumbar support, characterized in that at both ends of the elevating plate, a pair of locking pieces are formed that are sequentially caught in the plurality of locking grooves and temporarily fixed during the lifting operation of the elevating plate. In the chair applied with the backrest provided with the lumbar support according to any one of claims 1, 2, and 4 to 6,
leg part,
A seat portion connected to the upper side of the leg portion so that the user can sit on it; and
A backrest connected to the rear of the seat and having the lumbar support installed thereon;
A chair with a lumbar support, characterized in that the degree of protrusion and height of the lumbar support are adjustable.

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