KR101788642B1 - Up-down and revolution apparatus of a board back for chair - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backrest slide apparatus for a chair, and more particularly, to a backrest sliding apparatus for a chair which includes a seat plate 110 on which a user is seated, a backrest And a backrest frame 130 for supporting the backrest 120 to extend upward from the rear of the seat 110 so as to face the backrest 120. The backrest 120 includes: The backrest 120 is provided to face the upper portion of the backrest frame 130 so as to face the backrest frame 130 in accordance with the pressure applied to the backrest 120 to slide the backrest 120 in the vertical direction The upper and lower slide portions 210 of the upper and lower slide portions 210 and the lower end portions of the backrest 120 and the backrest frame 130, According to provide a chair backrest device for a slide consisting of a plurality of front and rear retractable portion 220 that guides able to compensate for the travel distance and the rotation distance of the backrest (120).

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a back-

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backrest slide apparatus for a chair, and more particularly, to a slide apparatus for a backrest, which is capable of guiding upward and downward slide movement and forward- backward rotation of a backrest between a backrest frame and a backrest, And a backrest slide device for a chair which is slidable upward and downward in accordance with a user's movement according to a physical condition of a user and a sitting posture so as to comfortably support the back of the user while relieving the fatigue of the user and feeling a sense of comfort will be.

Generally, there are various kinds of chairs depending on the use, and most of them have a back which can support the waist of the seated person and the back.

In the case of a chair having such a backrest, a backrest formed in a curved shape corresponding to a human body curve extending from a back portion to a waist so as to support a back part and a waist of a user seated in the seat is applied.

However, when the user's posture changes in the direction in which the waist of the user seated in the chair is separated from the back, the load of the user dispersed through the back is dispersed only through the seat, thereby increasing the fatigue of the user.

In addition, when the user changes his or her posture in a direction in which the backrest is tilted back while the user is seated in the chair, the waist portion is spaced from the backrest as the back portion is stretched in the human body structure, thereby increasing the fatigue of the waist There is a problem.

In order to solve such a problem, Korean Patent Registration No. 1014860 (issued on February 15, 2011) discloses an invention called "waist supporting chair".

1 and 2, the chair disclosed in Japanese Patent Laid-Open Publication No. 10-1486060 includes a seating section 10 in which a user is seated, and a seating section 10, which is opposed to a back section of a user seated in the seating section 10, A backrest frame 30 formed to extend upward from the seat back 10 and a hinge 29 provided at an upper portion of the backrest frame 30 so as to be rotatable to a waist portion of a user seated in the seating portion 10, The backrest 20 and the backrest frame 20 can be moved in a direction in which the lower end of the backrest 20 is away from the backrest frame 30 so as to apply an elastic biasing force to the backrest 20, And an elastic bias portion provided between the first electrode and the second electrode.

The elastic bias portion includes a torsion portion 48 wound in a coil shape and a torsion spring 48 formed in an A shape having first and second support portions 46 and 44 extended to both sides from the torsion portion 48 And a torsion spring 42 is inserted through the torsion portion 48 of the torsion spring 42. The torsion spring 42 is provided at a portion of the backrest frame 30 opposed to the backrest portion 20, And a first engaging piece 33 formed with a supporting groove 33c for receiving the first supporting portion 46 of the torsion spring 42 is formed

The backrest 20 is provided with a support groove 23c having a receiving groove 33c for receiving the first engaging piece 33 and supporting the second supporting portion 44 of the torsion spring 42, The support pin 37 has a hollow portion and a deformed portion 37c in which a terminal portion is deformably deformed and the hinge 29 is engaged with a second engagement piece Through the through hole (24) formed so as to be mutually spaced apart from each other in a state of being inserted through the hollow of the support pin (37), the portion corresponding to the deformation portion (37c) The deformation portion 37c permits the passage of the hinge 29. When the waist portion 29c enters the waist portion 29c, So that the first engaging piece 33 can be retracted so as to block the retraction of the hinge 29. As shown in FIG.

As described above, in the above-mentioned document, a chair is proposed in which a backrest 20 fixed to the upper end of a backrest frame 30 is supported by a backrest 20 while the backrest 20 is attached to the back of a seated person. However, Since it is structured to move back and forth while being tangential, it is not fixedly fixed to the back of a seated person, and thus it is not suitable for a candidate or a person engaged in the task of concentrating their mind.

Korean Patent Registration No. 1547268 (published on Aug. 26, 2015) discloses a chair capable of adjusting the inclination of the backrest plate.

As shown in Fig. 3, the chair disclosed in Japanese Patent No. 1547268 includes a seating portion in which a user is seated, and a back portion extending upward from the seating portion to support a back portion of a user seated in the seating portion, A backrest frame 2 which is rotatably mounted on the backrest frame 2 by a hinge on the upper portion of the backrest frame 2 and extends downward to support a waist portion of the user seated in the seating portion, 2, a backrest plate 3 having an extension protrusion 31 formed at its lower end in contact with the lower extension 21 of the backrest plate 3, a lower extension 31 of the lower end of the backrest plate 3, And a hinge-fixed inclination adjusting unit 4 which is inserted into the seat portion 21 and is capable of adjusting the inclination angle of the backrest plate 3 by allowing the lower end of the backrest plate 3 to protrude forward and backward, .

Here, the backrest frame 2 is formed with a hinge protrusion 22, which is protruded forward and has a square hinge hole 22a formed therein. The hinge protrusion 22 is bent at the lower end of the hinge protrusion 22, 21a are pierced in the direction of the backrest plate 3. The lower extension 21 is formed by bending the lower extension 21 in the direction of the backrest plate 3. [

The backrest plate 3 is formed with a hinge protrusion 32 which is protruded rearward corresponding to the hinge protrusion 22 of the backrest frame 2 and in which a hinge hole 32a is formed, An extension protrusion 31 protruding rearward at a position corresponding to the portion 21 and having an operation hole 31a formed therein is formed.

The actuating hole 31a of the extension projection 31 of the backrest plate 3 is formed with two or more continuously formed curved portions so that the lower portion of the backrest plate 3 can be projected forward.

The inclination adjusting part 4 is formed with a shaft hole 41a formed eccentrically and has a handle 41b on which a user's finger is positioned and pivoted to a portion exposed to the outside, The inserted portion is provided with an axial concave portion 41c extending coaxially with the axial hole 41a and a protruding operation portion 41c projecting from one side of the axial concave portion 41c, And a pivoting main body 41 including a pivot 41d.

With such a configuration, a backrest plate which can be moved back and forth is adjusted by adjusting the inclination adjusting unit provided at the lower end of the backrest plate so that the user of the chair can comfortably use the backrest while being able to support the user's back in a more comfortable posture So that it is possible to sit comfortably while concentrating on the user's work, thereby improving the efficiency of the work.

However, even in the case of a chair capable of adjusting the inclination of the backrest plate disclosed in the above-mentioned document, the backrest plate is rotatably connected to the backrest frame by the hinge so that it can not slide up and down. There is a disadvantage that it can not actively cope with.

On the other hand, in addition to the above-mentioned prior arts, various prior arts related to a chair or a tiltable chair of a backrest capable of adjusting the angle of a chair's backrest have been variously disclosed.

For example, Korean Patent Registration No. 0946664 (issued on March 9, 2010) and Korean Patent Registration No. 1009488 (issued on January 20, 2011) have a chair capable of giving a cushion feeling by elastic rotation of the backrest at a predetermined angle Lt; / RTI >

As described above, various technologies relating to a chair which can feel the comfort of the user and maintain health even during the use of the chair for a long period of time have been researched and developed.

Korean Registered Patent No. 1014860 (issued on February 15, 2011, entitled "Waist Support Chair") Korean Registered Patent No. 1547268 (issued May 2015, issue name: chair capable of adjusting the inclination of the backrest plate) Korean Registered Patent No. 0946664 (issued on March 9, 2010, entitled "Chair with Adjustable Backrest Angle") Korean Patent Registration No. 1009488 (issued on January 20, 2011, entitled "Chair with a tilting backrest")

Accordingly, the present invention has been developed in order to provide a chair having a functional back which can provide comfort and comfort to the user in a form different from that of a chair back which is adjusted or tilted in various angles.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a slide device for guiding the up and down slide movement and the forward and backward rotation of the backrest between the backrest frame supporting the back of the backrest and the backrest, The back and forth sliding movement of the back and forth according to the movement of the user, and the user comfortably supports the back of the user while relieving the fatigue of the user and feeling a sense of comfort.

In order to achieve the above object, according to the present invention, there is provided a seat for a vehicle, comprising: a seat on which a user is seated; a back which extends downward to support a back portion and a waist portion of a user seated on the seat; The backrest being provided so as to be opposed to the left and right between the upper portion of the backrest and the backrest frame so that the backrest is moved up and down relative to the backrest frame in accordance with the pressure applied to the backrest And a pair of upper and lower slide portions provided between the lower end portions of the backrest and the backrest frame so as to oppose each other in the left and right directions so as to move the upper and lower slide portions up and down and the backward movement of the backrest, A plurality of front and rear It has its features to provide a chair backrest device for a slide-part forward and backward.

According to a preferred embodiment of the present invention, the up-and-down slide unit includes a connecting bracket protruding from the back surface of the upper back and lower sliding unit, the hinge pin passing through the connecting bracket and the fixing bracket, A slider guide plate having a connecting pin assembly hole through which a connecting pin is inserted and inserted into one side of the slider, a support plate formed on a lower surface of the slider guide plate, and a slider guide plate coupled to an upper portion of the backrest, And a slider guide hole for guiding a connection pin which is connected to the slider guide plate so as to be movable in a vertical direction along the slider guide plate so as to be in line with the connection pin assembly, A slider having a pressure plate formed thereon, A first elastic member of a compression spring type disposed and mounted between the support plate of the guide plate and the pressure plate of the slider, and a coil spring portion fitted in the hinge pin connecting the connection bracket and the fixing bracket, And a second elastic member having a configuration in which the support portions deployed in the form of being seated on the inner circumferential surface of the connection bracket and the fixing bracket are respectively disposed on both sides of the lower end portion of the back portion of the backrest, And a pin insertion hole formed in the lower end of the backrest frame so as to be mutually fitted so as to be opposite to the moving piece and capable of compensating a moving distance of the moving piece to be inserted, A moving ball for guiding a moving pin which is connected in a state of being positioned on a line is disposed in the longitudinal direction And a backrest sliding device for a chair including a coupling guide formed therein.

According to the present invention, the slide device can be vertically and horizontally slidable between the backrest frame supporting the back of the backrest and the backrest, and the backrest can be slid up and down according to the user's movement, The cushioning feeling is provided to relieve the fatigue of the user and to feel the comfort.

Particularly, according to the present invention, since the slide device constituted by the upper and lower slide portions and the forward and backward advancement and retreating portions are provided at the upper and lower ends of the backrest and the backrest respectively so as to face each other, So that it is possible to stably implement the back and forth movement and rotation of the backrest.

Fig. 1 is a perspective view of a waist supporting chair disclosed in Patent Publication No. 1014860 in the prior art. Fig.
Fig. 2 is an exploded perspective view of the backrest and the backrest frame shown in Fig. 1 according to the prior art; Fig.
FIG. 3 is an exploded perspective view of a chair back portion disclosed in the prior art publication No. 1547268. FIG.
4 is a perspective view schematically showing a state in which a slide device is installed between a backrest and a backrest frame according to the present invention;
5 is an exploded perspective view showing the structure of the upper and lower slide portions of the slide device according to the present invention.
6 is an exploded perspective view showing the configuration of the front and rear forward and backward portions among the slide apparatuses according to the present invention.
FIG. 7 is a view showing a state before operation of the slide device, and FIG. 8 is a view showing a state after operation of the slide device Fig.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In order to explain the preferred embodiments of the present invention, the thicknesses of the lines and the sizes of the components shown in the attached drawings may be exaggerated or omitted for clarity and convenience of description, Terms to be given are terms defined in consideration of the functions of the present invention, which may vary depending on the intention or custom of the user, the operator.

4, the chair 100 according to the present invention has a structure in which the seat panel 110 and the backrest 120 are coupled and supported by a backrest frame 130 having a supporting function, like a conventional chair, A backrest 120, a backrest frame 130, a support leg 140, and an armrest 150. The armrest 150 includes a seat back 110, a backrest 120, a backrest frame 130,

In this case, the seat 110 is configured to be seated and fixed by the support leg 140 and the center shaft 141, which are supported on the ground.

The seat plate 110 is formed of a material having a cushioning feeling on the normal seat frame 111.

The seat frame 111 is connected to a backrest frame 130 which supports the seat 100 so that the user can sit on the seat 110 and can support the backrest 120.

The backrest frame 130 includes a rectangular frame 132 having an internal hollow shape and a frame assembly 131 extending from a lower central portion of the rectangular frame 132 and fitted into the seat frame 111 ).

The backrest frame 130 is mounted on the rear of the seat frame 111 through the frame assembly 131 and fastened and assembled to the backrest frame 130. The backrest frame 130 is mounted on the square frame 132 integrally formed with the frame assembly 131, The backrest frame 130 according to the present invention has a generally skeletal structure in its entire skeleton.

Of course, the backrest frame 130 applied to the present invention is not limited to the shape structure in which the inside of the rectangular frame 132 is formed in an empty state, as shown in the drawing, and the rectangular frame 132 itself may be a complete plate- Structure.

The support leg 140 is composed of a radial bridge which is assembled to a center shaft 141 supporting the bottom surface of the seat 110 and is disposed to abut against the ground surface. .

The armrests 150 are coupled to both side surfaces of the seat frame 111 to form a T-shape so that a seated user can hold his or her arms when the seat is lifted up or down, do.

Reference numerals 160 and 161 denote a headrest 160 assembled to the backrest frame 130 to support a head portion of a seated person and a headrest 160 connected to the backrest frame 130 The connection frame 161 is a connection frame.

In a conventional chair having the above-described structure, the present invention is characterized in that it has the following functional structure so as to improve the backrest function of a chair.

That is, according to the present invention, the backrest 120 is connected to the backrest frame 130 by the slide device 200 as shown in FIG. 4, and moves up and down according to the pressure applied to the backrest 120 And can be actuated back and forth in accordance with the physical condition and sitting posture of the seated person.

4 to 6, the slide device 200 installed between the backrest 120 and the backrest frame 130 according to the present invention includes the upper portion of the backrest 120 and the backrest frame 130) And a plurality of forward and backward advancement and retraction parts 220 installed to face each other between the lower end of the backrest 120 and the backrest frame 130 to face each other.

That is, the upper and lower slide portions 210 and the forward and backward movement portions 220 are symmetrically disposed on the upper and lower four sides of the rectangular frame 132 constituting the backrest frame 130, Four positions on the upper and lower ends of the back surface are coupled to the back frame 130 and can be firmly fixed.

The upper and lower slide units 210 slide up and down in a state in which the backrest 120 is rotated slightly about the hinge pin 216 with respect to the backrest frame 130 according to the pressure applied to the backrest 120 5, the upper and lower slide portions 210 largely include a slider guide plate 211, a slider 212, a first elastic member 217, and a second elastic member 218 .

That is, the slider guide plate 211 is a member hingedly coupled to the upper end of the rectangular frame 132 of the backrest frame 130 through a hinge pin 216 to have a substantially diagonal cross-sectional structure, And a diaphragm-type connection bracket 214 is integrally formed to protrude from the side surface of the hinge pin 216.

The upper end of the rectangular frame 132 of the backrest frame 130 is engaged with the connection bracket 214 so as to be rotatably hinged to the connection bracket 214 of the slider guide plate 211 Shaped locking bracket 215 is formed to protrude toward the front of the backrest 120. As shown in Fig.

The fixing bracket 215 may be integrally formed when the rectangular frame 132 is formed, may be separately manufactured and may be coupled to the rectangular frame 132 by welding or the like, or may be fastened by a fastener to be.

The connection bracket 214 and the fixing bracket 215 are formed with hinge holes 214a and 215a aligned in a mutually engaged state so as to be coupled to each other by the hinge pin 216 in a state of being interlocked with each other, And a pin fixing nut 216a is fastened to one end of a hinge pin 216 fitted into the hinge holes 214a and 215a formed in the connection bracket 214 and the fixing bracket 215, 216 are fastened and fixed so as not to be separated from the hinge holes 214a, 215a.

The connection bracket 214 and the stationary bracket 215 are connected to each other by a hinge pin 216. The hinge pin 216 is connected to the stationary bracket 215 by a spring member A second elastic member 218 made of a metal is mounted and assembled.

When the pressure applied to the backrest 120 is transmitted to the upper and lower slide units 210 and the backrest 120 slides upward and downward by the upper and lower slide units 210, When the pressure acting on the upper and lower slide portions 210 is released by the elastic member which is elastically displaced so as to have an elastic restoring force as the hinge pin 211 is hinged about the hinge pin 216 and is pressed by the rotation pressure, So that the slider guide plate 211 can be returned to the initial state.

5, the second elastic member 180 has a coil spring portion fitted in a hinge pin 216 connecting the connection bracket 214 and the fixing bracket 215, The support bracket 214 and the fixing bracket 215 are arranged on the inner circumferential surface of the connection bracket 214 and the fixing bracket 215 so that the slider guide plate 211 can be pressed against the backrest frame 130 The backrest 120 elastically supports the backrest 120 when the backrest 120 is slid in the vertical direction and rotates back and forth according to the pressure applied to the backrest 120, The operation is returned to the initial state.

The slider 212 has a generally diagonal cross-sectional structure and is coupled to the backrest 120 by being engaged with the slider guide plate 211 so as to be slidable up and down. In a preferred embodiment of the present invention, the slider guide plate 211 Are slidably engaged with each other to form a slider guide plate (211).

At this time, sliding slits 212a are formed on both sides of the slider 212 and a pressing plate 212b is formed on an inner side surface of the slider 212 where the sliding slits 212a are terminated.

The pressing plate 212b of the slider 212 is moved in the upward and downward sliding movement along the slider guide plate 211 fixed to the backrest frame 130 by the pressure applied to the backrest 120, The slider guide plate 211 is formed with a pressing plate 212b formed on the slider 212 and a pressing plate 212b formed on the slider guide plate 211 when the slider guide plate 211 and the slider 212 are coupled to each other. A hollow space having a predetermined height is formed between the support plates 211b so that the first elastic member 217 in the form of a compression spring can be inserted and disposed in the empty space.

When the slider guide plate 211 and the slider 212 are assembled with each other, the connection pin 213 is engaged with the slider guide plate 211 The connection pin assembly 211a and the slide slot 212a formed in the slider 212 are engaged with each other through the connection pin assembly hole 211a and the slide slot 212a.

When the slider 212 is slid up and down along the slider guide plate 211, the connection pin 213 is connected to the connection pin 213 ) Is guided along the slide slot 212a.

At this time, a connection pin fixing hole 213a is formed at one end of the connection pin 213, which is inserted through the connection pin assembly hole 211a and the slide slot 212a, to fix the connection pin fixing hole 213a.

The upper and lower slide units 210 are coupled to each other so as to face each other between the backrest 120 and the backrest frame 130 in a configuration including the slider guide plate 211 and the slider 212, The backrest 120 and the backrest frame 130 are spaced from each other by a predetermined distance from the vertical backrest frame 130 due to the upper and lower slide portions 170, And is provided with sufficient space to be pivotable about the hinge pin (216).

4 and 6, the front and rear forward / backward parts 220 are moved up and down relative to the backrest frame 130 in accordance with the pressure applied to the backrest 120 The lower portion of the backrest 120 is moved back and forth to the back frame 130 in order to compensate for the upward and downward travel distance of the backrest 120 by the up and down slide unit 210. [

To this end, the forward and backward moving parts 200 are composed of a moving piece 221 and a coupling guide piece 222 as shown in FIG.

The back and forth moving parts 220 are connected to both sides of the lower end of the backrest 120 so as to protrude from the back part of the backrest 120. The moving pieces 221 are inserted into the back frame 120, And a coupling guide piece 222 which is formed at the lower end of the base plate 132.

The coupling guide piece 222 is a member having a slide groove in which the moving piece 221 can be inserted and slidably moved while the moving piece 221 is slidable. Is formed.

When the moving piece 221 and the coupling guide piece 222 are coupled to each other in the moving slot 222a, the pin insertion holes 221a formed in the moving piece 221 are positioned on the same line, The moving piece 221 and the coupling guide piece 222 are coupled to each other.

The moving slot 222a serves to guide and guide the moving line within the engaging guide piece 222.

At this time, a pin fixing nut 223a is fastened and assembled to one end of the moving pin 223, which is inserted through the pin insertion hole 221a and the moving slot 222a, to secure the fastened state.

Since the moving piece 221 and the coupling guide piece 222 have a structure in which they are fitted to each other, they have a structure in which they are opposed to each other. In the preferred embodiment of the present invention, The backrest 120 has a rectangular bar type protruding from both sides of the back surface of the backrest 120 toward the backrest frame. In correspondence thereto, the a coupling guide piece 222 has a rectangular pipe shape And has a structure in which a moving slot 222a is formed on a side surface thereof so as to engage with the backrest frame 130 and is coupled to the backrest frame 130 side.

Of course, the shape of the moving piece 221 and the coupling guide piece 222 is not limited to the shape shown in the accompanying drawings, and the moving piece 221 and the coupling guide piece 222 are fitted to each other It is natural that design changes can be made in various forms if they have a shape and a shape structure capable of compensating the movement distance of the backrest due to up-and-down movement and rotation.

When the user uses the chair according to the present invention in which the slide apparatus 200 having the above-described structure is applied between the backrest 120 and the backrest frame 130, as shown in FIGS. 7 and 8, When the user is seated on the seat back 110 and pressure is transmitted to the backrest 120 according to the sitting posture, the backrest 120 is slid up and down about the upper and lower slide portions 210 and the forward and backward advancement portions 220, It will be done.

For example, when the user pushes the hips backward in the sitting posture, the backrest 120 is moved downward about the upper and lower slide portions 210 as pressure is applied to the lower end of the backrest 120 So that the back of the user can naturally come into close contact with the back of the user, thereby stably supporting the back of the user while giving a cushion feeling.

The first and second elastic members 217 and 218 may be disposed in the sliding device 200 between the backrest 120 and the backrest frame 130 according to the pressure applied to the backrest 120. [ The moving distance and the turning angle of the backrest 120 are appropriately adjusted in the vertical direction and the back and forth direction according to the intensity of the pressure applied to the backrest 120, When the pressure is removed, the elastic restoring force of the first elastic member 217 and the second elastic member 218 causes the backrest 120 to return to the initial state.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be construed as limiting the scope of the invention as defined by the appended claims. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.

100: Chair 110: Seat
111: a seat frame 120: a backrest
130: backrest frame 131: frame assembly
132: square frame 140: support leg
141: center shaft 142: wheel
150: Armrest 160: Headrest
161: connection frame 200: slide device
210: upper and lower slide part 211: slider guide plate
211a: Connection pin assembly hole 211b:
212: Slider 212a: Slide slot
212b: pressure plate 213: connecting pin
213a: connection pin fixing member 214: connection bracket
214a, 215a: Hinge hole 215: Fixing bracket
216: Hinge pin 216a: Hinge pin fixing nut
217: first spring member 218: second spring member
220: forward and backward advancing / retracting portion 221:
221a: pin insertion hole 222:
222a: moving slot 223: moving pin
223a: Pin fixing nut

Claims (2)

A backrest 120 extending downward so as to support a back portion and a waist portion of the user seated on the seat back 110 and a backrest 120 facing the backrest 120, And a backrest frame 130 which is formed to extend upward from the rear of the backrest 120 and which supports the backrest 120,
The backrest 120 can be slidably moved in the vertical direction with respect to the backrest frame 130 in accordance with the pressure applied to the backrest 120 by being horizontally opposed between the backrest 120 and the upper end portion of the backrest frame 130, A plurality of upper and lower slide portions 210 for pivotally guiding,
The backrest 120 and the backrest frame 130 are provided so as to face each other in the left and right directions to compensate the movement distance and the rotation distance of the backrest 120 due to the up-and-down slide movement and the front- And a plurality of forward and backward advancing / retracting portions (220)
The upper and lower slide unit 210 includes a connection bracket 214 protruding from the back surface of the backrest frame 130 so as to be opposed to the fixing bracket 215 formed on the upper portion of the backrest frame 130. The connection bracket 214 and the fixing bracket 215 A connecting pin assembly hole 211a through which a hinge pin 216 is pivotally coupled and rotatably engaged with a connecting pin 213 is formed on one side of the hinge pin 216 and a supporting plate 211b is formed on a lower end surface of the connecting pin assembly hole 211a, The slider guide plate 211 is coupled to the upper end of the backrest 120 and surrounds the front surface of the slider guide plate 211 and is assembled so as to face the slider guide plate 211 through the connection pin 213, A slide slot 212a for guiding a connection pin 213 to be inserted and connected in a state in which it is positioned on the same line as the connection pin assembly hole 211a so as to be movable in the vertical direction is formed, The pressure plate 212b A first resilient member 217 of compression spring type disposed and mounted between the support plate 211b of the slider guide plate 211 and the pressure plate 212b of the slider 212, A coil spring portion is fitted to the hinge pin 216 connecting the bracket 214 and the fixing bracket 215. A supporting portion opened at an acute angle around the coil spring portion is connected to the connection bracket 214 and the fixing bracket 215 , And a second elastic member (218) having a shape structure that is seated and disposed on the inner peripheral surface of the second elastic member
The forward and backward movement part 220 includes a moving piece 221 having a pin insertion hole 221a formed on both sides of the lower end of the backrest 120 and protruding therefrom and through which the movement pin 223 can be inserted, The pin insertion hole 221a is coupled to both side surfaces of the lower end portion of the backrest frame 130 so as to be mutually fitted so as to be opposed to the moving piece 221 and to compensate the moving distance of the moving piece 221 to be inserted. And a moving guide hole (222a) for guiding a moving pin (223) inserted and connected in a state of being located on a line is formed in the longitudinal direction.
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