WO2004037047A1

WO2004037047A1 - Structure of chair backrest

Info

Publication number: WO2004037047A1
Application number: PCT/JP2003/012919
Authority: WO
Inventors: Takashi Nakamura
Original assignee: Kokuyo Furniture Co.,Ltd.; Takano Co., Ltd.
Priority date: 2002-10-11
Filing date: 2003-10-08
Publication date: 2004-05-06
Also published as: CN1713841A; CN100420404C; AU2003272952A1

Abstract

A structure of a chair backrest that can be used with a back board set at a preferred angle of bend. The structure comprises a back support member (61) having a first back frame (1) tiltably attached to a seat-receiving member (8) and a second back frame (5) tiltably attached to the first back frame (1), and comprises a back board (2) having a back board-bending region (2e), a back board upper portion (2a) positioned more upward than the back board-bending region (2e), and a back board lower portion (2b) positioned more downward than the back board-bending region (2e). The back board lower portion (2b) is fixed to the first back frame (1), and the back board upper portion (2a) is supported by the second back frame (5). The back board (2) is bendable forward by deforming the back board-bending region (2e). A bending angle-adjusting mechanism (3) is provided in the structure, and the mechanism makes it possible that an angle of bend of the back board is varied and fixed by adjusting the tilt angle of the second back frame (5) with respect to the first back frame (1).

Description

Specification

Chair backrest structure

The present invention relates to a chair backrest structure. More specifically, the present invention relates to an improvement in a back plate supporting structure that allows the shape of the backrest to be deformable.

Background art

2. Description of the Related Art Conventionally, a backrest structure of a chair in which a backboard is bent in accordance with the weight of a seated person has been known (EP 0 519 933 A1). As shown in Fig. 46, this backrest structure has a back support rod 101, which is elastically deformable in the front-rear direction and is supported by a shaft 103. 0 4 is provided, and the lower end of the back plate 102 is displaced to the back support rod 101 by inserting the pin 105 attached to the lower end of the back plate 102 into the long hole 104. It is connected as much as possible. A spring 106 for urging the back plate 102 forward is provided between the back support rod 101 and the back plate 102.

The back support rod 101 is attached to the seat plate 107 so as to be tiltable, and is constantly urged by a spring mechanism (not shown) in a direction in which it is erected. Since the back support rod 101 is tilted against the urging force of the spring mechanism, when the occupant leans lightly on the back plate 102, the back support rod 101 tilts slightly backward. On the other hand, when the occupant leans strongly against the back plate 102, the back support rod 101 is greatly inclined backward.

When the occupant leans on the backboard 102, the upper part of the backboard 102 is pushed more strongly at the top and bottom, and as shown by the two-dot chain line in Fig. 46, the backboard 1 02 tilts around the shaft 103 so that the upper side is tilted backward. At this time, since the lower end of the back plate 102 is connected to the dorsal support 101 by the pin 105, it cannot move forward, but moves upward in the elongated hole 104. . Therefore, the lower portion of the back plate 102 near the center protrudes forward below the shaft 103, and the entire back plate 102 is deformed into a bent shape.

When the occupant leans lightly on the back plate 102, the back plate 102 bends slightly, and when leaning strongly, the back plate 102 bends greatly. That is, the bending angle of the back plate 102 changes according to the strength with which the seated person leans on the back plate 102. However, in the above-described backrest structure, since the bending angle of the back plate 102 changes according to the strength with which the occupant leans, the occupant leans strongly and pushes the back support rod 101 back largely. If it is tilted, the back plate 102 will bend significantly. For this reason, the back support rod 101 could not be largely tilted backward with the back plate 102 bent slightly.

Also, when the seated person leans lightly and tilts the back support rod 101 backward slightly, the back plate 102 cannot be bent significantly. For this reason, the back support rod 101 could not be tilted backwards slightly while the back plate 102 was largely bent. Further, unless the seated person leans on the backrest, the backboard 102 cannot be bent and maintained in that state. In other words, the chair could not be used with the bending angle of the back plate 102 set to the desired angle.

Further, as a conventional backrest structure capable of changing the shape of the backrest, for example, there is a chair disclosed in Japanese Patent Application Laid-Open No. 2000-237778. In this chair, as shown in Fig. 47, a pair of back support rods arranged on the left and right are composed of a rigid upper frame 201 and a lower frame 202, which are hard to deform. The upper frame 201 and the lower frame 202 are connected by a pivotal member 203 so that the angle is variable. In addition, a rigid bracket 204 that is hard to deform is mounted near the upper end of the upper frame 201 so as to be variable in angle, and a resin or the like is provided between the bracket 204 and the lower frame 202. A belt 205 is attached as a bendable reinforcing member formed of a material having the above elasticity. The back plate 206 is attached to the bracket 204 and the lower frame 202 so as to sandwich the left and right belts 205.

The back plate 206 includes a lower shell 206 b and an upper shell 206 c, and is connected to bend at a bent portion 206 a. When the occupant leans against the backrest, the lower shell 206b moves rearward, and the tension of the belt 205 and the elasticity of the backplate 206 causes the upper seal 206c to rotate forward. . For this reason, the back of the seated occupant can be supported by the backrest, for example, when looking at the monitor screen of the personal computer while leaning on the backrest.

However, this backrest support structure is designed so that The back plate 206 is made of a flexible material such as resin, or a slit is formed in the middle of the back plate 206 because it is rigidly supported at both ends of the back plate 206. Even if the back plate 206 is easily deformable, it can be deformed in the front-back direction (the depth direction of the chair), but the center of the backrest is centered on the axis passing in the longitudinal direction (mainly the vertical direction) It is impossible to impart torsion or deformation to the backboard 206, and it is difficult to deform the backboard 206 according to the posture of the seated person with the torsion. For example, if the occupant twists his body and leans on the right side of the backrest, taking a reclining posture while deforming the back plate 206 along the occupant's back so as to twist it to the right rear side, etc. It was difficult. Furthermore, the backrest support structure cannot deform the backboard so that the waist portion is pushed forward when the backrest is tilted backward.

An object of the present invention is to provide a chair backrest structure that can use a chair in a state where a bending angle of a backboard is set to a desired angle. Further, an object of the present invention is to provide a backrest structure of a chair capable of satisfactorily deforming a backboard according to a posture of a seated person.

Disclosure of the invention

In order to achieve the object, a chair backrest structure of the present invention includes at least one first back frame tiltably attached to a seat receiving member, and a tiltably attached to the first back frame. A back support member having at least one second back frame, a back plate bending region, a back plate upper portion located above the back plate bending region, and a lower side of the back plate bending region. A back plate having a lower back plate positioned thereon, and one of the upper back plate and the lower back plate is fixed to the first back frame, and one of the other is supported by the second back frame. The backboard can be bent as a whole by deforming the backboard bending area and tilting the other back and forth with respect to one side, and adjusts the tilt angle of the second backframe with respect to the first backframe. To change the bending angle of the backboard And a bending angle adjusting mechanism for fixing the bending angle.

Therefore, the bending angle of the backboard can be adjusted to a desired angle by operating the bending angle adjusting mechanism. After adjusting the bending angle of the backboard to the desired angle, operate the bending angle adjustment mechanism to fix the bending angle, that is, to prevent the bending angle from changing. Even if the occupant leans strongly against the back plate, the bending angle of the back plate is maintained by the bending angle adjustment mechanism. It is. As described above, the back plate can be used in a state where the bending angle is adjusted to a desired angle, so that it is possible to improve the sitting comfort, use, and operability of the chair.

In addition, the backrest structure of the present invention includes a lower back plate fixed to the first back frame, an upper back plate tiltable in the front-rear direction, a bending angle adjustment mechanism, and a lower end of the first back frame. A second back frame, the upper end of which can be tilted in the front-rear direction around the connection point, and a connection connecting the upper end of the second back frame to the upper part of the back plate while absorbing these relative displacements Means, a connecting point force between the first back frame and the second back frame, and a displacement means provided at a remote position to change a distance between the first back frame and the second back frame. It is provided with.

Therefore, when the distance between the first back frame and the second back frame is changed by operating the displacement means, the second back frame tilts with respect to the first back frame. Since the upper end of the second back frame is connected to the upper portion of the back plate, the tilt angle of the second back frame changes the bending angle of the back plate. At this time, since the amount of movement of the upper end of the second back frame is different from the amount of movement of the second back frame connecting portion of the back plate, the upper end of the second back frame is connected to the second back frame of the back plate. Although the relative displacement occurs between the first and second portions, the connecting portion absorbs the relative displacement, and makes the tilting of the second back frame and the bending of the back plate smooth. That is, the bending angle of the backboard can be adjusted by operating the displacement means, and the bending angle of the backboard can be adjusted to a desired angle by a simple adjustment operation. In addition, since the relative displacement generated between the upper end of the second back frame and the second back frame connecting portion of the back plate can be absorbed by the connecting means, the mechanism can be established.

The backrest structure of a chair according to the present invention includes a deformable backplate and at least one back support member at least a portion connected to the backplate is formed of a flexible resin. is there. Therefore, when the occupant leans on the back plate, the back support member flexes according to the magnitude, direction, and position of the applied load, and the back plate is easily deformed. The back plate is deformed, so that the leaning comfort can be improved.

Further, the backrest structure of the chair according to the present invention includes a connecting means for connecting the upper end of the back support member to the upper part of the back plate while absorbing these relative displacements. In this case, When the plate is deformed, a relative displacement occurs between the upper end of the back support member and the connecting portion of the back support member of the back plate, but the connection portion absorbs the relative displacement, and the back plate is deformed larger and more smoothly. Let it. That is, the relative displacement between the back support member and the back plate can be absorbed by the connecting means. For this reason, it is possible to prevent an excessive force from being applied to the connecting portion between the back support member and the back plate, and it is possible to further easily deform the back plate, thereby further improving the reclining comfort.

Further, the backrest structure of the chair according to the present invention includes: at least one first back frame tiltably attached to the seat receiving member; and at least one first back frame tiltably attached to the first back frame. A back support member having a second back frame, a back plate bending region, an upper portion of the back plate positioned above the back plate bending region, and a first position positioned below the back plate bending region and And a connecting means for connecting the upper end of the second back frame to the upper part of the backboard while absorbing these relative displacements. By deforming and tilting the upper part of the backboard in the front-back direction with respect to the lower part of the backboard, the backboard can be bent as a whole, and at least the upper part of the backboard can be deformed, and the second back frame can be used. It is made of flexible resin It is.

Therefore, when the seated person leans on the backboard, the second back frame tilts the upper part of the backboard, so that the backboard can be bent in the front-rear direction around the backboard bending area. At the same time, the back plate is easily deformed with a radius depending on the magnitude, direction, and position of the load applied to the second back frame, and the back plate follows the posture of the seated person and is deformed with twisting or locally. Easy to deform. Therefore, the leaning comfort can be improved.

Further, the backrest structure of the chair according to the present invention includes: at least one first back frame tiltably attached to the seat receiving member; and at least one first back frame tiltably attached to the first back frame. A back support member having a second back frame, a back plate bending region, an upper portion of the back plate positioned above the back plate bending region, and a first position positioned below the back plate bending region and The backboard has a backboard fixed to the back frame of the backboard, and the backboard can be bent as a whole by deforming the bending area of the backboard and tilting the top of the backboard forward and backward with respect to the lower backboard The bending angle of the back plate is changed and the bending angle is fixed by adjusting the tilt angle of the second back frame with respect to the first back frame. A second back frame having a lower end connected to the first back frame and an upper end capable of tilting in the front-rear direction about the connection point; Connecting means for connecting the upper end of the second back frame to the upper part of the back plate while absorbing these relative displacements, and provided at a position distant from a connection point between the first back frame and the second back frame. Displacement means for changing the distance between the first back frame and the second back frame, wherein at least the upper part of the back plate is deformable, and the second back frame is flexible It is formed of a resin having

In this case, when the occupant leans on the back plate, the second back frame bends easily according to the magnitude, direction, and position of the applied load, so that the deformable back plate is easily deformed. In other words, it is possible to suppress the deformation of the back plate from being hindered by the second back frame, so that the back plate deforms locally or with a twist according to the posture and movement of the seated person, The leaning comfort can be improved. In addition, by operating the bending angle adjusting mechanism, the bending angle in the front-rear direction around the bending region of the backboard can be adjusted to a desired angle. If the bending angle of the backboard is adjusted to the desired angle and the bending angle is fixed, the bending angle of the backboard is maintained by the bending angle adjustment mechanism even if the occupant leans strongly against the backboard.

That is, when the distance between the first back frame and the second back frame is changed by operating the displacement means, the second back frame tilts with respect to the first back frame. Since the upper end of the second back frame is connected to the upper part of the back plate, the tilt angle of the second back frame changes the bending angle of the back plate. At this time, since the amount of movement of the upper end of the second back frame is different from the amount of movement of the second back frame connecting portion of the back plate, the upper end of the second back frame is connected to the second back frame of the back plate. Although the relative displacement occurs between the first and second portions, the connecting portion absorbs the relative displacement, and makes the tilting of the second back frame and the bending of the back plate smooth. That is, the bending angle of the back plate can be adjusted by operating the displacement means, and the bending angle of the back plate can be adjusted to a desired angle by a simple adjustment operation. In addition, since the relative displacement generated between the upper end of the _second back frame and the _second back frame connecting portion of the back plate can be absorbed by the connecting means, the mechanism can be established. Further, in the backrest structure of the chair according to the present invention, the displacement means includes a first back frame and a second back frame. An adjusting screw provided on one of the back frames, a female screw member provided on one of the other sides and having a screw hole into which the adjusting screw is inserted, and an angle of at least one of the adjusting screw and the female screw member in a vertical direction. It is provided with angle changing means for changing.

Therefore, when the adjusting screw is rotated, the screwing amount of the female screw member into the screw hole changes. Therefore, the distance between the first back frame and the second back frame at a position apart from the connection point between the first back frame and the second back frame changes, and the tilt angle of the second back frame changes. And the bending angle of the backboard changes. That is, the bending angle of the back plate can be adjusted by rotating the adjusting screw. In addition, with the change in the tilt angle of the second back frame and the bending angle of the back plate, the opposing angle between the adjusting screw of the displacement means and the screw hole also changes, but this change is absorbed by the angle change means, so the displacement No excessive force is generated in the means, light! / Can be operated by force.

In the backrest structure for a chair according to the present invention, the connecting means includes a shaft portion having a circular contour formed at least at an upper end of the second back frame, and is relatively rotatable relative to the shaft portion and slidable in the axial direction. It has a flexible connecting portion and a shaft supporting means for attaching the connecting portion to the back plate so as to be rotatable in a vertical direction, and the connecting portion has a length that does not fall off the shaft portion.

Therefore, the relative displacement of the second back frame in the axial direction is absorbed by, for example, the cap-shaped connecting portion sliding in the axial direction with respect to the shaft portion. In addition, the vertical rotation of the connecting portion with respect to the back plate, that is, the angle change, absorbs the change in the vertical angle between the second back frame and the back plate. Further, the rotation of the connecting portion with respect to the shaft portion absorbs a change in the horizontal angle between the second back frame and the back plate. In other words, the relative displacement in the axial direction of the second back frame, the change in the vertical angle between the second back frame and the back plate, and the change in the horizontal angle between the second back frame and the back plate are well absorbed. can do.

Further, in the backrest structure of the chair of the present invention, the connecting means includes a shaft portion having a circular contour formed at least at an upper end of the second back frame; A shaft receiver having an inlet formed therein, and a member provided above the shaft receiver and defining a space for allowing movement of the tip of the shaft portion. Things.

Therefore, when the shaft moves in the axial direction with respect to the shaft receiver, the second back frame is moved. Absorbs relative displacement in the axial direction of one meter. (4) The shaft portion makes a razor movement with respect to the entrance, thereby absorbing a vertical angle change and a horizontal angle change between the second back frame and the back plate. Further, the rotation of the shaft with respect to the shaft receiver absorbs a change in the horizontal angle between the second back frame and the back plate. As a result, the degree of freedom of movement of the connecting portion between the second back frame and the back plate can be improved. In addition, the number of components is reduced, and the number of manufacturing processes is accordingly reduced, so that manufacturing costs can be reduced.

Further, in the backrest structure of the chair of the present invention, at least one slit is formed in the backboard bending region so that the upper portion or the lower portion of the backboard can be tilted in the front-rear direction. In this case, the rigidity of the back plate is locally reduced due to the presence of the slit, and the back plate is easily deformed in the portion where the rigidity is intentionally reduced, that is, in the bent region of the back plate. It can be easily tilted in any direction. That is, the back plate can be bent in the front-rear direction with a simple configuration. In this case, if the shape of the slit is at least a shape protruding in one direction, for example, a U-shape, a part of the back plate can be protruded to form the support portion. Further, by making the shape of the slit linear, it is possible to prevent a part of the back plate from protruding. The back plate bending area is intentionally formed to enable bending of the back plate at an arbitrary position.However, in some cases, a region where the back plate is bent and deformed is also included, and the back plate is fixed. It is formed between the portion and the connecting portion. The backrest structure of the chair according to the present invention is further characterized in that a support member for assisting the backrest is rotatably attached to the upper end of the backboard, and the support member and the first back frame are connected by a link, thereby bending the backboard. The support member is rotated in conjunction with. Therefore, even if the occupant leans against the backboard and takes a posture in which the head is raised, the head and the like can be supported by the support member. For this reason, the usability of the chair can be improved.

Further, in the backrest structure of the chair of the present invention, the resin is glass-filled nylon.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a sectional view showing an embodiment of a backrest structure of a chair according to the present invention. Fig. 2 is a cross-sectional view showing the backrest structure of the chair, with the backboard bent significantly. Fig. 3 is a rear view showing the back plate of the backrest structure of the chair. Fig. 4 shows the connecting means of the backrest structure of the chair, and is a cross-sectional view seen from above. Fig. 5 shows the connecting means and is a cross-sectional view from the side. Fig. 6 is a cross-sectional view showing a first example of a displacement means of the backrest structure of the chair. Fig. 7 shows the same displacement means, and is a cross-sectional view of the back plate with the back plate bent significantly. Fig. 8 is a perspective view showing the angle changing means of the displacement means. Fig. 9 is a plan view showing the gas spring attached to the backrest structure. Fig. 10 is a side view showing the gas spring. Fig. 11 is a rear view showing the cover of the backrest structure of the chair. Fig. 12 is a rear view showing the cover attached to the back plate. Fig. 13 is a side view showing another embodiment of the connecting means constituting the backrest structure of the chair of the present invention. Fig. 14 is a sectional view showing a second example of the displacement means of the backrest structure of the chair. Fig. 15 shows a second example of the displacement means, and is a cross-sectional view in a state where the back plate is greatly bent. Fig. 16 is a sectional view showing a third example of the displacement means of the backrest structure of the chair. Fig. 17 shows a third example of the displacement means, and is a cross-sectional view of the state where the back plate is greatly bent. Fig. 18 is a sectional view showing a fourth example of the displacement means of the backrest structure of the chair. Fig. 19 shows a fourth example of the displacement means, and is a cross-sectional view of the back plate with the back plate largely bent. FIG. 20 is a side view showing a first modification of the backrest structure of the chair of the present invention. Fig. 21 is a side view showing a second embodiment of the backrest structure of the chair of the present invention, showing a state where the lower portion of the backboard is tilted forward. Fig. 22 is a diagram showing the use state of the chair of Fig. 20. Fig. 23 shows the chair in use, showing the lower part of the backboard tilted forward. Fig. 24 is a side view showing a third embodiment of the backrest structure of the chair of the present invention. Fig. 25 is a side view showing a second modification of the backrest structure of the chair of the present invention, and showing a state where the lower portion of the backboard is tilted forward. Fig. 26 is a sectional view showing a fourth embodiment of the backrest structure of the chair according to the present invention. Fig. 27 shows the use state of the chair to which the backrest structure of Fig. 26 is applied, and shows how the chair is used by children. Fig. 28 shows the use of the chair to which the backrest structure of Fig. 26 is applied, showing how an adult uses it. Fig. 29 shows a fifth embodiment of the backrest structure of the chair to which the present invention is applied, and is a cross-sectional view showing a state where the headrest is moved rearward. Fig. 30 shows a fifth embodiment of the backrest structure of the chair, in which the headrest is moved forward. FIG. Fig. 31 shows the use state of the chair to which the backrest structure of Fig. 29 is applied, in which the headrest is moved backward. Fig. 32 shows the use state of the chair to which the backrest structure is applied, in which the headrest is moved forward and the entire backrest is reclined. Fig. 33 is a rear view showing the slits on the back plate with steps. Fig. 34 is a rear view showing the appearance of two slits on the back plate. Fig. 35 is a rear view showing a single slit in the back plate. Fig. 36 is a cross-sectional view showing another embodiment of the connecting means constituting the backrest structure of the chair to which the present invention is applied. Fig. 37 is a conceptual diagram for explaining the shape of the insertion port and the movement of the projection. Fig. 38 is a sectional view showing still another embodiment of the connecting means constituting the backrest structure of the chair to which the present invention is applied. Fig. 39 shows a sixth embodiment of the backrest structure of the chair according to the present invention, which is provided with a support member for supporting from the scapula portion of the seated person to the head as a support member. It is a figure of the state where it is moving back. FIG. 40 shows a sixth embodiment of the backrest structure, in which the support body is moved forward and the entire backrest is reclined. Fig. 41 is a perspective view showing how the upper part of the backboard is twisted and deformed. Fig. 42 is a perspective view showing how the center of the back plate is deformed so as to protrude backward. Fig. 43 is a perspective view showing how the back plate is deformed so that one side protrudes backward. FIG. 44 is a schematic configuration diagram of a first back frame, a back plate, and a second back frame showing a seventh embodiment of the backrest structure of the chair of the present invention. Fig. 45 shows a seventh embodiment of the backrest structure of the chair of the present invention, and is a schematic configuration diagram of the first back frame, the back plate, and the second back frame with the back plate reclining. is there. Fig. 46 is a side view showing the backrest structure of a conventional chair. Fig. 47 is a side view showing the backrest structure of another conventional chair.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the configuration of the present invention will be described in detail based on the best mode shown in the drawings. In each of the embodiments, the same members are denoted by the same reference numerals, and redundant description will be omitted.

1 to 12 show a first embodiment of a backrest structure for a chair according to the present invention. The backrest structure of the chair (hereinafter, simply referred to as a backrest structure) includes at least one first back frame 1 that is tiltably attached to the seat receiving member 8 and the first back frame. A back support member 61 having at least one second back frame 5 tiltably attached to 1; and a back plate upper portion having a back plate bending region 2 e and being higher than the back plate bending region 2 e. A back plate 2 having a back plate 2a and a back plate lower portion 2b below the back plate bending region 2e is provided. One of the upper back plate 2a and the lower back plate 2b is fixed to the first back frame 1, and the other is supported by the second back frame 5, and the back plate bending area 2e By tilting the upper back 2a or the lower back 2b in the front-back direction with respect to the lower back 2b or the upper back 2a, the back plate 2 can be bent as a whole. I have.

In the backrest structure of the present embodiment, the back plate lower portion 2b is fixed to the first back frame 1, and the back plate upper portion 2a is connected to the second back frame 5 so as to be able to be linked in the front-rear direction. By tilting the upper back plate 2a in the front-rear direction with respect to the lower back plate 2b, the back plate bending region 2e is deformed so that the back plate 2 can be bent around the bending region 2e. Have been. However, the mounting relationship of the back plate 2 to the back support member 61 is not limited to the above embodiment, and the upper portion 2a of the back plate is fixed to the first back frame 1 and the lower portion 2b of the back plate 2 The support frame 2 may be supported by the back frame 5.

The back support member 61 for supporting the backrest in the backrest structure of the present embodiment is composed of two side plates 1 d swingably mounted on the seat member 8 and a back plate mounting wall 1 f and a reinforcing plate 1. One first back frame 1 connected and integrated with g, etc., and two rigid rod-like rods such as steel pipes that are attached to the side plate 1 d of the first back frame 1 so as to be tiltable. It is composed of one second back frame 5 in which objects are connected by connecting plates 11 and 12 and integrated.

Further, the backrest structure includes a bending angle adjusting mechanism 3 that changes the bending angle of the back plate 2 and fixes the bending angle by adjusting and fixing the tilt angle of the second back frame 5 with respect to the first back frame 1. Is provided. The bending angle adjusting mechanism 3 of the present embodiment utilizes a feed screw mechanism, and has a variable distance between the first back frame 1 and the second back frame 5. That is, the lower end of the second back frame 5 is connected to the rear end of the first back frame 1 by the pin 4, and is provided so as to be tiltable in the front-rear direction about the connection pin 4. This second back frame ⁵ , connecting means 6 for connecting the upper end of the second back frame ^{5 to} the upper part 2a of the back plate, and a position away from the connecting pin 4 And a displacement means 7 for connecting the first back frame 1 and the second back frame 5 to change the distance between the first back frame 1 and the second back frame 5 in the first embodiment. 3 are configured.

The first back frame 1 is attached to the seat receiving member 8 so as to be tiltable. The lower back 2b of the back plate 2 is fixed to the first back frame 1. The first back frame 1 is swingably attached to the seat receiving member 8 by a connecting pin 8 1 so that the back plate 2 is always erected by a reaction force unit 8 3 mounted on the seat receiving member 8. Has been biased. The seat receiving member 8 has a long hole 85 at the distal end side, and a shaft 84 is passed through the long hole 85 to support the seat 9 so as to be able to move back and forth. The rear end of the seat 9 is hooked on a shaft 82 penetrating the back support member 61 and is supported by the back support member 61. Therefore, the seat 9 moves back and forth with the tilt of the back support member 61, and sinks or lifts the rear side.

The lower part 2b of the back plate is fixed by screws or screws using the back plate mounting wall 1f. In addition, a member denoted by reference numeral 1 g in the figure is a connecting member that connects the left and right first back frames 1.

The back plate 2 is made of, for example, a flexible material. In the present embodiment, the back plate 2 is formed of, for example, a resin such as polypropylene or nylon. However, the resin used as the material of the back plate 2 is not limited to these, and the back plate 2 may be formed of a material other than the resin. In the present embodiment, the back plate 2 is made to be bendable by being made of a flexible material such as resin, but the back plate upper portion 2a and the back plate lower portion 2b of the back plate 2 are formed as separate members. The back plate 2 may be bendable by connecting the back plate upper portion 2a and the back plate lower portion 2b with a hinge or the like. In this case, the hinge is the back plate bending area 2 e. The hinge is, for example, integrally formed with the upper back plate 2a and the lower back plate 2b of the back plate 2, and is more flexible than the resin used as the material of the upper back plate 2a and the lower back plate 2b. It is possible to apply a resin hinge formed by using a certain resin, and it is formed integrally with the back plate upper part 2a and the back plate lower part 2b of the back plate 2, and the back plate upper part 2a and the back plate lower part 2b It is possible to apply a hinge that has flexibility by making it thinner.

In the present embodiment, the back plate 2 has both side edges curved forward. However, by forming the slit 10, a bending region 2 e that is easily bent in the front-rear direction is formed. Is formed. In the present embodiment, a slit having a shape protruding at least in one direction, for example, a U-shaped slit 10 is employed, but the shape of the slit 10 is not limited to this, and for example, However, the shape may be an inverted U-shape, H-shape, V-shape or inverted V-shape, W-shape, or a shape similar to a pseudo-mark, or other shapes. The protruding portion of the slit 10 of the back plate 2, in this embodiment, the upper portion is a tongue piece 2c. Further, the shape of the slit 10 is not limited to the U-shape shown in the figure, and may be a linear shape. In this case, it is sufficient that at least one slit 10 exists, for example, two slits 1 ° may be provided as shown in Fig. 34, or one slit 10 as shown in Fig. 35. A slit 10 may be provided, and three or more slits 10 may be provided. In this manner, the slit 10 is formed to be easily deformed, and the upper part 2a of the backboard above the bending area 2e or the lower part 2b of the lower backboard is tilted in the front-back direction about the bending area 2e. Make it possible. Here, the bending region 2 e is a region between a portion where the back plate 2 is fixed to the first back frame 1 and a portion where the back plate 2 is connected to the second back frame 5. More specifically, the bending region 2 e is a region near the hinge that functions similarly to the slit 10 ゃ slit 10, and is generally represented by Figs. 3, 33, and 3. 4. In the range indicated by the imaginary line in Fig. 35, it is the area where positive elastic deformation is presumed. The bent region 2e is intentionally formed to allow the back plate 2 to bend at an arbitrary position, but may include a region which is bent as a result in some cases.

As shown in Fig. 3 etc., when the shape of the slit 10 is U-shaped and the tongue piece 2c is formed, that is, when the tongue piece 2c is projected downward, When the upper part of the plate 2 is inclined backward and bent, the tongue piece 2c can be projected forward, and the protruded tongue piece 2c can support the waist of the occupant. When it is not necessary to protrude the tongue piece 2c or when it is not preferable to protrude the tongue piece 2c, the shape of the slit 10 may be linear, or the bent area 2e may be continuous. It is composed of typical resin hinges. That is, by making the shape of the slit 10 linear, it is possible to prevent a part of the back plate 2 from projecting even if the back plate 2 is bent. The second back frame 5 is fixed to the first back frame 1 with the bending area 2 e as a boundary. In the case of the present embodiment, the back plate portion 2a above the bending region 2e is rotatably and slidably connected to the back plate 2 at the back plate portion opposite to the side of the back plate. It supports 2a. In the case of the present embodiment, for example, a circular pipe is employed as the second back frame 5, and two second back frames 5 are provided on the left and right sides, for example, so as to support both ends in the width direction (horizontal direction) of the back plate 2. . The second back frame 5 is connected by two connecting plates 11 and 12. At a lower end of the lower connection plate 12, a pair of brackets 12 a arranged to sandwich the first back frame 1 from both sides are fixed. By connecting a connecting shaft (hereinafter simply referred to as shaft 4) to each bracket 12 a and the first back frame 1, the lower end of the connection plate 12, that is, the second back frame 5 is attached to the first back frame 1. It is rotatably connected to the frame 1 around the shaft 4, and the upper end can be moved in the front-rear direction. The second back frame 5 is formed in a substantially Y-shape by connecting the two pipes with the connecting plates 11 1 and 12, and the arm portion above the connecting plate 11 has a gap between them. It is spread and the upper end is connected to the vicinity of the upper corner of the back plate 2 by connecting means 6. The number of the second back frames 5 is not limited to two, but may be one or three or more. For example, in the case of one second back frame 5, the center of the back plate 2 may be supported, or a T-shape may be used to support both ends of the back plate 2. The left and right pipe second back frames 5 are connected by two connecting plates 11 and 12. However, in some cases, one connecting plate requires at least rigidity as the second back frame 5. May be connected. Further, the second back frame 5 is formed of a circular pipe material, but may be a solid rod material or, in some cases, a square pipe or a square material.

For example, as shown in FIG. 5, the connecting means 6 includes a shaft 13 having a circular contour formed at least at the upper end of the second back frame 5, and a shaft rotatable relative to the shaft 13. A connecting part 14 slidable in the direction is provided, and a shaft support means 15 for rotatably attaching the connecting part 14 to the back plate 2 around a horizontal axis. In the present embodiment, since the second back frame 5 is a pipe having a circular cross section, the upper end of the second back frame 5 forms the shaft portion 13. The connecting portion 14 is a cap (hereinafter, referred to as a cap 14) having a circular inner peripheral surface that is fitted into the shaft portion 13 with a slight gap. However, the connecting portion 14 is not limited to the cap, and may be, for example, a ring or the like. It may be. In addition, the outer peripheral shape of the shaft portion 13 and the inner peripheral surface shape of the connecting portion 14 do not have to be circular in a strict sense, and rotation can be allowed in a movable range required between them. Any shape is sufficient.

The shaft support means 15 is rotatably connected to a bracket 14a fixed to the cap 14 and a bracket 2d fixed to the back plate 2 through these brackets 2d and 14a. This is a hinge joint composed of a shaft 16 to be mounted.

The cap 14 is fitted into the shaft 13 from above. By making the inner diameter of the cap 14 slightly larger than the outer diameter of the shaft 13, the cap 14 is rotatable with respect to the shaft 13 and slidable in the axial direction. The cap 14 has such a length that it does not fall off the shaft portion 13 within the range of movement of the second back frame 5. That is, even if the cap 14 slides with respect to the shaft portion 13 due to the tilting of the second back frame 5 and the bending of the back plate 2, the cap 14 does not come off from the shaft portion 13.

In the case of the present embodiment, the displacement means 7 includes an adjusting screw 17 provided on one of the first back frame 1 and the second back frame 5, and a female screw member 21 provided on the other. ing. The female screw member 21 has a rod shape, has a screw hole 18 into which an adjusting screw 17 penetrating in the radial direction is screwed, and is disposed so as to be orthogonal to the adjusting screw 17. The female screw member 21 and the adjusting screw 17 are attached to the first back frame 1 and the second back frame 5 so as to be adjustable in angle. In the present embodiment, an adjusting screw 17 is attached to the connection plate 12 that connects the second back frame 5, and a female screw member 21 is provided on the first back frame 1.

More specifically, the adjusting screw 17 is opened to the connection plate 12 having a slightly larger diameter or a longer hole (longer in the height direction of the backrest) than the adjusting screw 17 via the thrust bearing 20. It is attached to the connecting plate 12 so as to be rotatable, tiltable and adjustable in position, and not fall off by passing through a hole (not shown). Further, the female screw member 21 is disposed between the side plates I d and 1 d protruding from the back plate mounting wall 1 f of the first back frame 1, and both ends thereof are connected to the side plates 1 d of the first back frame 1. , Id and are screwed and supported on coaxial screws 22 and 22. The screws 22 pass through through holes 1 e formed in the side plate 1 d of the first back frame 1 and are screwed into screw holes formed at both ends of the female screw member 21. Therefore, the female screw member 21 is The first back frame 1 is rotatably supported on the screw 22 by angle changing means 19 rotatably supported by the screw 22 and the side plate 1d.

The screw hole 18 penetrates the center of the female screw member rod 21 in the radial direction. At the tip of the adjusting screw 17 screwed into the screw hole 18, a stop disk 23 is attached so that the adjusting screw 17 does not come out of the screw hole 18. An operating lip 43 is fixed to an end of the adjusting screw 17, and is provided so as to rotate the adjusting screw 17 using the grip 43.

In this backrest structure, the bending angle of the back plate 2 can be adjusted to a desired angle as described below.

In the state shown in Fig. 1 and Fig. 6, if the distance between the first back frame 1 and the second back frame 5 is increased by turning the adjusting screw 17, the second back frame 5 It falls backwards centering on ft4. At this time, the upper end of the second back frame 5 pulls the upper back plate 2a of the back plate 2 backward against the lower back plate 2b fixed to the first back frame 1, so that the back plate 2 is It bends by elastic deformation in the bending area 2e (Fig. 2, Fig. 7).

When the rotation operation of the adjusting screw 17 is stopped, the interval between the first back frame 1 and the second back frame 5 does not change, so that the tilt angle of the second back frame 5 is kept constant, and therefore, The bending angle of the back plate 2 can be kept constant, and the chair can be used in this state.

When the adjustment screw 17 is rotated in the opposite direction to the above operation, the distance between the first back frame 1 and the second back frame 5 is reduced, and the second back frame 5 is moved around the shaft 4. Rotate forward to raise backboard 2. As a result, the pulling force of the second back frame 5 in the direction of the back plate 2 is reduced, and the bending angle of the back plate 2 is reduced. That is, as shown in FIGS. 1 and 6, the bending angle of the back plate 2 can be returned to the original.

As described above, by adjusting the tilt angle of the second back frame 5 with respect to the first back frame 1, the bending angle of the back plate 2 can be changed and the bending angle can be fixed. Here, when the second back frame 5 is largely tilted with respect to the first back frame 1, the back plate 2 can be greatly bent, and the second By tilting the back frame 5 slightly, the back plate 2 can be bent slightly. That is, the bending angle of the back plate 2 can be adjusted.

According to the backrest structure of the present invention, when the occupant leans against the backboard 2 and tilts the backboard 2 with respect to the seat receiving member 8, that is, a force for rotating the adjustment screw 17 even during reclining. Since the bending does not occur, the bending angle of the back plate 2 does not change during use.

That is, the occupant can adjust the bending angle of the backboard 2 to a desired angle by operating the adjustment screw 17, and can use the chair with the backboard 2 bent at the desired angle. As a result, the usability of the chair can be improved. Further, it is easy to rotate the adjusting screw 17 and the adjusting work is also simple. This also improves the usability of the chair.

By using the chair with the bending angle of the backboard 2 increased, for example, when the first back frame 1 is tilted and the entire backrest is reclined, the back muscles can be further extended, A better stretching effect can be obtained.

The first back frame 1 is tilted with respect to the seat receiving member 8 by expanding and contracting a gas spring 24 with a lock mechanism that connects the rear end of the seat receiving member 8 and the middle of the first back frame 1. It becomes possible. That is, the gas spring 24 with the lock mechanism capable of restricting the expansion and contraction operation at an arbitrary position constitutes a triangular link mechanism together with the seat receiving member 8 and the first back frame 1 and locks the gas spring 24. When the mechanism can be released and extended, the first back frame 1 can be tilted, but the locking mechanism, for example, the locking mechanism that prevents the flow of the working gas, activates the gas spring 24. If the length is fixed, the first back frame 1 cannot be tilted. The length of the gas spring 24 is fixed or released by opening and closing a release valve that prevents the flow of the working gas by operating the lever 25. This lever 25 is located in the space below the side edge of the backboard 2 so that the occupant does not bend forward, and can be grasped simply by lowering his hand with his back on the backboard 2. It can be operated as it is. Therefore, it is easy to perform the lever operation, and it is also easy to perform the operation of pushing the back plate 2 with the back while operating the lever 25. Also, the gas spring 24 is linked from the valve operation part to the left and right direction of the chair. By extending 26, the lever 25 can be directly attached to the link 26, and a reasonable arrangement can be adopted. In other words, the gas spring 24, the link 26, the wrapper 25, and the like can be assembled to the chair in a previously assembled state, and the chair can be easily assembled.

When the inclination angle of the second back frame 5 changes, the height and inclination of the adjusting screw 17 change accordingly, so that the intersection angle between the female screw member 21 and the adjusting screw 17 changes, but the adjusting screw By rotating the female screw member 21 by the fine adjustment means and the angle changing means 19 with respect to the connection plate 12 of 17, the adjustment screw 17 and the screw hole 18 are always arranged in a straight line, and the adjustment screw 17 is It can always rotate smoothly. For this reason, the adjusting screw 17 can be operated with a light force, and is excellent in usability.

When adjusting the bending angle of the back plate 2 by tilting the second back frame 5, a portion connecting the movement amount of the upper end of the second back frame 5 and the second back frame 5 of the back plate 2. That is, since the movement amount of the link connecting portion is different, a relative displacement occurs between the upper end of the second back frame 5 and the link connecting portion of the back plate 2. However, this relative displacement is absorbed by the connecting means 6. That is, the relative displacement of the second back frame 5 in the axial direction can be absorbed by sliding the cap 14 in the axial direction with respect to the shaft portion 13. The change in the vertical angle between the second back frame 5 and the back plate 2 is absorbed by changing the relative angle between the back plate 2 and the cap 14 around the support shaft 16 of the shaft support means 15. can do. Further, a change in the horizontal angle between the second back frame 5 and the back plate 2 can be absorbed by the rotation of the cap 14 with respect to the shaft portion 13.

In this manner, the relative displacement generated between the upper end of the second back frame 5 and the link connecting portion of the back plate 2 can be absorbed by the connecting means 6, so that the second back frame 5 is A mechanism for bending the back plate 2 by tilting can be established. Also, since no excessive force acts on the connection between the second back frame 5 and the back plate 2, the back plate 2 can be moved smoothly, and the back plate 2 can be bent with a light force. And the feel is better. Furthermore, since an excessive force is prevented from acting on the connecting portion between the second back frame 5 and the back plate 2, it is possible to prevent damage and wear of members and components due to stress concentration, and to prolong the product life. it can. In addition, the degree of freedom in the selection of materials for each member and part, and the degree of freedom in the combination of materials between sliding and contacting parts and parts are improved. Can be

In addition, the back plate 2 of the present embodiment made of a flexible material has a structure in which the cap 14 rotates with respect to the shaft portion 13 so that, as viewed from above, as shown in FIG. It becomes easy to curve the back plate 2 so that the center of the back plate 2 projects rearward. That is, when the occupant leans on the back plate 2, the back plate 2 is easily curved in accordance with the shape of the back. Therefore, the sitting comfort can be further improved.

Although not shown in Figs. L to 3, 6, and 7, the cushioning material 27 stored in the bag-like cover 28 is provided on the front of the back plate 2. Installed. As shown in Fig. 11, the cover 28 has a pocket-shaped folded portion 28a at the upper edge of the back surface and a pocket portion opening upward at a position facing the slit 10 of the back plate 2. 28 b are provided respectively. Incidentally, the shape of the pocket portion 28b is a shape corresponding to the shape of the slit 10 and the tongue piece portion 2c. An elastically deformable insole plate 29 is placed in the folded portion 28a to adjust the shape of the upper edge of the cover 28 and to prevent the folded portion 28a from wrinkling or bending. To make it easy to turn over the folded part 28a.

To attach the cushioning material 27 covered with the force par 28 to the back plate 2, first, pass the cover 28 to the tongue piece of the back plate 2 through the slit 10 of the back plate 2. After covering over 2c from below, it is sufficient to cover the upper edge of the back plate 2 while turning over the upper folded portion 28a. At this time, cover 28 covers pocket 28b on tongue 2c of backboard 2 so that it can be hooked, and then extends upward while pulling back folded part 28a of backboard 2. It can be attached by putting it on the upper end. Also, since the folded part 28a of the force par 28 is placed on the upper edge of the back plate 2 and the bocket 28b is placed on the tongue piece 2c, the cover 28 is left and right with respect to the back plate 2. There is no deviation in the direction. In this way, the cushioning material 27 can be attached to the back plate 2 simply by covering the folded portion 28a of the cover 28 from above and covering the pocket portion 28b from the bottom through the slit 10. Installation work is very easy. In addition, the cushion material 27 can be attached at an accurate position both vertically and horizontally.

That is, in the conventional method, when the cover 28 for storing the cushioning material 27 is attached to the back plate 2, the cover 28 is fixed to the back plate 2 with a pin or a hook-and-loop fastener. (The so-called magic tape). In some cases, a folded part 28 a was provided on the upper edge of the cover 28 to cover the upper edge of the back plate 2, but even in this case, the lower part of the cover 28 was pinched using pins or hook-and-loop fasteners. It was stopped on board 2. Therefore, in the conventional method, it was troublesome to attach the force par 28 containing the cushioning material 27 to the back plate 2, and the workability was poor. On the other hand, according to the cover-mounting method of the present embodiment, there is no need to perform a troublesome work of stopping using pins or hook-and-loop fasteners. Since there is no need to perform work such as positioning on the back plate, workability is extremely excellent, and manufacturing costs can be reduced.

Also, since the folded part 28 a and the pocket part 28 b of the force par 28 can be seen from the back of the chair, the color of the back plate 2 and the color of the cover 28 can be different so that the folded part 28 The a and the boket part 28b become components on the design, making it a design that has never existed before, and can be differentiated from other types of chairs.

Further, with the cover 28 attached to the back plate 2, the pocket 28b can be used as a pocket for storing small items such as a mobile phone. The above-described embodiment is an example of a preferred embodiment of the present invention, but is not limited thereto, and various modifications can be made without departing from the gist of the present invention. For example, in the embodiment of FIGS. L to 12, the back plate 2 is formed of a material or a structure that can be deformed in any direction, and the second back frame 5 is formed as a flexible structure. May be. Specifically, the back plate 2 is made of a resin such as polypropylene or nylon similarly to the above-described embodiment. Further, at least a portion of the second back frame 5 connected to the back plate 2 is formed of a flexible resin. Here, the resin forming the second back frame 5 is preferably a resin filled with a reinforcing material such as glass fiber or carbon fiber, but the back plate 2 is satisfactorily deformed according to the posture of the occupant. There is no particular limitation as long as it has the required rigidity to form the backrest structure. In the present embodiment, for example, nylon containing glass is used. Further, it is not necessary to make all the portions of the second back frame 5 have the same rigidity, and the rigidity may be partially changed. For example, the rigidity of this arm portion is lower than the rigidity of the lower portion than the portion connected by the connection plate 11 of the second back frame 5. May be smaller. As a means of changing the rigidity, for example, the filling amount of glass in nylon is made different between the upper side and the lower side, and in some cases, the upper half is made of nylon with glass fiber and the lower half is made of metal and joined It is possible to do. In this manner, when the back plate 2 is made deformable and at least a portion connected to the back plate 2, for example, the second back frame 5 is formed of a flexible resin, the back plate 2 follows the posture and movement of the seated person. As a result, the back plate 2 is easily deformed, so that the leaning comfort can be improved.

For example, if the occupant leans on one side of the backboard 2 (a position deviated from the centerline 59 of the backboard 2), the fork branches above the connection point of the second back frame 5 by the connection plate 11. Of the two arms, the arm with the stronger weight of the occupant has a larger radius, and the arm with no weight acts on the back plate 2 due to the deformation of the back plate 2. Is pulled forward. That is, as shown in Fig. 41, the back plate 2 is deformed so that the upper end of the back plate 2 is twisted about the center line 59 of the back plate 2. That is, since the arm portion of the second back frame 5 bends, it is difficult to hinder the deformation of the back plate 2, and the back plate 2 can be largely deformed into a shape that follows the posture of the seated person. When the occupant leans on the center of the backboard 2 (on the center line 59), the two arms of the second back frame 5 bend inward. As shown in Fig. 5, the center of the back plate 2 is greatly curved so as to protrude backward. That is, since the arm portion of the second back frame 5 bends, it becomes difficult to hinder the deformation of the back plate 2, and the back plate 2 can be largely deformed into a shape that follows the posture of the seated person. Furthermore, as shown in Fig. 43, it is possible to deform only one side of the backboard 2. In other words, only one of the two arm portions of the second back frame 5 is largely deflected, and the back plate 2 can be largely deformed into a shape that follows the posture of the seated person. Further, the upper side of the back plate 2 may be curved so as to be warped backward. In these cases, the connecting means 6 smoothes the movement of the back plate 2 and the second back frame 5 without suppressing the movement of twisting and bending. The first back frame 1 in addition to the second back frame 5 may be formed of a flexible resin such as nylon reinforced with glass fiber or the like. In this case, the back plate 2 is more easily deformed than when only the second back frame 5 is formed of a flexible resin, and in particular, as shown in FIG. This is effective when the plate 2 is torsionally deformed. In the present invention, at least a portion connecting the back plate 2 of the second back frame 5 is formed of a flexible resin so that the deformation of the back plate 2 is not hindered. Therefore, the degree of freedom of deformation of the back plate 2 can be increased with a simple structure, and the number of parts does not increase.

Further, in the above-described backrest structure in which at least a portion of the back plate 2 and the back support member 61 that supports the upper portion of the back plate 2 can be deformed, it is necessary to bend the seat plate 2 from the bending region in the front-rear direction. In this case, the first support frame 61 made of metal and the second back frame 5 made of reinforced resin do not constitute the back support member 61, but the first The back frame 1 and the second back frame 5 may be integrally formed. That is, it is sufficient that at least a portion of the back support member 61 that is connected to the back plate 2 and supports the back plate 2, for example, the upper portion is formed of a flexible resin so as to be easily bent. That is, at least the upper portion of the back support member 61 may be formed of a flexible resin as long as the back plate 2 can be deformed favorably.

Further, the mounting structure of the cushion material 27 can be applied to the back plate 2 provided with the slit 10 and forming the tongue piece portion 2c irrespective of the structure of the back support member 61. .

Further, although the above-described pocket portion 28b is opened upward, the pocket portion 28b may be opened downward. In this case, as shown in FIG. 33, the slit 10 is formed in an inverted U shape so that the tongue piece 2c is formed upward.

In addition, it is a matter of course that a means that can be engaged with the tongue piece 2c, for example, a band or the like may be provided instead of the pocket 28b. For example, when a band is provided instead of the pocket 28b, the band is formed even if the slit 10 is U-shaped, even if the slit 10 is inverted U-shaped. The cover 28 can be attached to the back plate 2 by locking the tongue piece 2 c. As shown in Fig. 33, the slit 10 may be provided with a step 10a to prevent the band 28c from coming off the tongue 2c.

Further, in each of the above-described embodiments, the connecting means 6 includes the shaft portion 13, the cap 14, and the shaft supporting means 15, but the configuration is not necessarily limited to this. For example, as shown in the connection means 6 shown in Fig. 13, the link bracket is attached to the upper end of the second back frame 5. Along the axial direction of the second back frame 5, a slot 31 is provided along the axial direction of the second back frame 5, and a back plate side bracket 32 is fixed to the back plate 2, and a long A pin 33 passing through the hole 31 may be attached. By moving the pin 33 in the elongated hole 31, the relative displacement of the second back frame 5 in the axial direction can be absorbed. In addition, the rotation of the pin 33 in the elongated hole 31 can absorb a change in the vertical angle between the second back frame 5 and the back plate 2. In the example of Fig. 13, the long hole 31 is provided on the second back frame 5 side and the pin 33 is provided on the back plate 2 side, but the pin 33 is provided on the second back frame 5 side. An elongated hole 31 may be provided on the back plate 2 side.

Further, as shown in FIGS. 34 to 36, for example, the connecting means 6 includes a shaft portion 51 having a circular contour formed at least at an upper end of the second back frame 5 and a back surface of the back plate 2. A shaft portion 51 provided with the shaft portion 51 inserted from below to allow the shaft portion 51 to be tilted; a shaft portion bearing 53 formed with an inlet 52; and a shaft portion provided above the shaft portion bearing 53; A member 55 that defines a space 54 that allows the movement of the tip of 51 may be provided. In the example of Fig. 36, a box (hereinafter referred to as a box 55) is formed on the back of the back plate 2 as the member 55, and the bottom wall of the box 55 is a bearing 53, a box. The interior space of 55 is defined as space 54. However, it is a matter of course that the structure for forming the bearing 53 and the space 54 is not limited to the box 55.

Fig. 37 shows the concept of the insertion port 52. The opening of the insertion opening 52 is formed with a conical surface extending toward the inside of the shaft portion bearing 53 and to both surfaces on the front side. For this reason, it is easy for the shaft 51 inserted into the inlet 52 to make a razor movement with respect to the shaft bearing 53, and the relative position between the back plate 2 and the second back frame 5 is increased. The degree of freedom of movement is improved as compared with the combination of the cap 14 and the shaft 13 of FIG.

When adjusting the bending angle of the back plate 2 by tilting the second back frame 5, a portion connecting the movement amount of the upper end of the second back frame 5 and the second back frame 5 of the back plate 2. In other words, since the movement amount of the link connecting portion is different, a relative displacement occurs between the upper end of the second back frame 5 and the link connecting portion of the back plate 2, and the connecting means 6 absorbs the relative displacement. I do. That is, the relative displacement of the second back frame 5 in the axial direction can be absorbed by moving the shaft portion 51 in the axial direction with respect to the shaft portion bearing 53. In addition, the relative angle change between the second back frame 5 and the back plate 2 is such that the shaft portion 51 is misaligned with the shaft portion bearing 53. It can be absorbed by rubbing. Further, a change in the horizontal angle between the second back frame 5 and the back plate 2 can be absorbed by the rotation of the shaft 51 with respect to the shaft bearing 53. '

In this type of connecting means 6, the shaft supporting means, that is, the hinge 15 required for the connecting means 6 shown in FIG. 5 can be omitted. For this reason, the structure is simpler than that shown in Fig. 5, and the number of parts can be reduced, and the number of manufacturing processes can be reduced. Can be lowered.

However, as shown in Fig. 38, the box part 55 of the connecting means 6 is connected to the back plate 2 by the pin 56, and the box part 55 is attached to the back plate 2 so as to be rotatable vertically. You may do it.

The displacement means 7 is a combination of a long hole 34 having a plurality of concave portions 34 a and a pin 36 passing through the long hole 34, as shown in FIGS. 14 and 15. The structure may be composed of This displacement means 7 attaches a plate 35 on which a long hole 34 having a plurality of recesses 34 a is formed to the second back frame 5 or the connecting plate 12, and attaches the first back frame 1 to the first back frame 1. Pin 36 is attached so that pin 36 passes through slot 34. A long hole 37 is provided in the vicinity of the lower end of the plate 35, and the shaft 4 is passed through the long hole 37 so that the second back frame 5 can move up and down as a whole. I have.

According to the displacement means 7, when changing the tilt angle of the second back frame 5, the second back frame 5 is lifted, and the pin 36 is removed from the concave portion 34a of the elongated hole 34, and the second back frame 5 is removed. The tilt angle of the back frame 5 is changed so that the pin 36 faces the adjacent or other concave portion 34a, and the second back frame 5 is lowered in this state. That is, the bending angle of the back plate 2 can be adjusted by changing the position of the concave portion 34 a into which the pin 36 is fitted. The weight of the second back frame 5 and the like can prevent the pins 36 from coming off the recesses 34a, so that the tilt angle of the second back frame 5 can be fixed, and during use, The bending angle of the back plate 2 can be fixed.

FIGS. 14 and 15 show an example in which two concave portions 34 a are provided. The number of the concave portions 34 a is not limited to two. Number of recesses 3 4 a By increasing the number, the number of tilt angles of the second back frame 5 that can be selected is increased, and the bending angle of the back plate 2 can be adjusted in multiple stages.

Further, the displacement means 7 may have a cam structure. Fig. 16 and Fig. 17 show an example where the displacement means 7 has a cam structure. In this displacement means 7, a cam plate 38 is rotatably attached to a flange 12b provided so as to protrude from the back plate 2 side of the connection plate 12 by a pin 46. A long hole 38a is formed in the cam plate 38, and the rotation angle of the cam plate 38 is limited to a certain range by passing the fixing pin 39 through the long hole 38a. I have. By rotating an operation lever (not shown), the cam plate 38 can be rotated to change the distance between the second back frame 5 and the back plate 2. When the distance between the second back frame 5 and the back plate 2 is reduced by operating the cam plate 38, that is, when the cam plate 38 is operated from the state of Fig. 17 to the state of Fig. 16 In other words, the back plate 2 does not separate from the cam plate 38 because the back plate 2 tries to return to the original shape by its own elastic force and tries to reduce the bending angle. That is, when the pushing force by the cam plate 38 is released, the back plate 2 reduces the bending angle due to its own natural force. In the rotation operation of the cam plate 38, the cam plate 38 itself may be directly driven, or the pin 46 may be rotated. In the displacement means 7 using a cam structure, the rotation angle of the cam plate 38 can be fixed to an arbitrary angle, so that the bending angle of the back plate 2 can be adjusted steplessly. In addition, by making the shape of the cam portion of the cam plate 38 into a polygon, the tilt angle of the second back frame 5 can be changed stepwise, and the bending angle of the back plate 2 can be changed in multiple steps. Can be adjusted.

Further, the displacement means 7 may have a link structure as shown in FIGS. In this displacement means 7, the connecting plate 12 fixed to the second back frame 5 and the back plate 2 are connected by two links 40, 41 which are flexibly connected to each other. A return spring 42 is mounted between the back plate 2 and the back plate 2 in a compressed state. In the state shown in Fig. 19, the second back frame 5 is tilted backward while the two links 40, 41 are extended by the urging force of the return spring 42, and the bending angle of the back plate 2 is increased. I have. Also, when the two links 40, 41 are contracted or bent against the urging force of the return spring 42, as shown in Fig. 18, The second back frame 5 stands and the bending angle of the back plate 2 decreases. The bending angle of the back plate 2 can be adjusted by changing the bending angle of the two links 40 and 41 by operating means (not shown) and fixing the bending angle. In the displacement means 7 using the link structure, the bending angle of the back plate 2 can be adjusted steplessly by fixing the two links 40 and 41 at an arbitrary bending angle.

In the above description, the bending angle of the back plate 2 is increased by tilting the upper end of the second back frame 5 rearward, so that, for example, during reclining, the back of the occupant can be stretched more. Although it was possible to obtain the better stretching effect, it is not always necessary to use this configuration.

For example, as shown in FIGS. 20 to 23, the lower back 2b of the back plate 2 may support the buttocks of the seated person. In this example, the first back frame 1 is extended upward, and the back plate upper portion 2 a of the back plate 2 is fixed to the first back frame 1. Also, the lower portion 2b of the back plate 2 can be tilted in the front-rear direction. The upper end of the second back frame 5 is rotatably attached to the first back frame 1 so as to be suspended. The lower end of the second back frame 5 is connected to the lower back plate 2 of the back plate 2. By tilting the second back frame 5 back and forth by operating the displacement means 7, it is possible to change the bending angle of the back plate 2 and tilt the back plate lower portion 2b back and forth. For example, by tilting the lower back plate 2b of the back plate 2 toward the front, the lower back plate 2b becomes a buttocks support for supporting the buttocks of the occupant, and a feeling of support when sitting can be obtained. A bent region 2e is formed at the boundary between the upper portion 2a of the back plate 2 and the lower portion 2b of the back plate 2 by a resin hinge or the like.

As shown in Figs. 24 and 25, the second back frame 5 is omitted, and a displacement means 7 is provided between the first back frame 1 and the lower portion 2b of the back plate 2. Alternatively, the displacement of the displacement means 7 may be directly transmitted to the lower portion 2b of the back plate. Also in this case, the lower part 2b of the back plate, that is, the buttocks support can be tilted back and forth by changing the bending angle of the back plate 2 by operating the displacement means 7.

Further, as shown in Fig. 26, the height of the back plate 2 may be adjustable. The first back frame 1 is further divided into a lower frame 1a and an upper frame 1b, and a vertically-opening cylindrical portion 1c provided at a tip of the lower frame 1a is formed into an upper frame. 1b is inserted, and the height of the back plate 2 is adjusted by sliding the upper frame 1b with respect to the cylindrical portion 1c. The connection between the upper frame 1b and the cylindrical portion 1c is performed, for example, by connecting the plurality of holes 47 provided in the upper frame 1b with the holes 48 of the cylindrical portion 1c in a state where the connecting pins 49 are aligned. This is performed by penetrating through. By locking the upper frame 1b to the cylindrical portion 1c, the back plate 2 can be fixed at the adjusted height. By adjusting the height of the back plate 2, the height of the bent portion of the back plate 2 can be changed. As shown in Fig. 27 and Fig. 28, adjusting the height of the back plate 2 according to the physique of the occupant improves the sitting comfort. Fig. 27 shows a child sitting, and Fig. 28 shows an adult sitting.

As shown in FIGS. 29 to 32, a support member for assisting the backrest may be provided in addition to the backrest. That is, the support member 44 is attached to the upper end of the back plate 2 so as to be rotatable in the front-rear direction, and the support member 44 and the first back frame 1 are connected by the link 45 so as to interlock with the bending of the back plate 2. Alternatively, the support member 44 may be tilted. As the support member 44, for example, a headrest 44 can be cited. The usage conditions are shown in Fig. 31 and Fig. 32. The lower end of the headrest 44 is rotatably attached to the upper end of the back plate 2, and the upper end of the head rest 44 is connected to the first back frame 1 by a link 45. The link 45 is rotatably connected to the headrest 44 and the first back frame 1. As shown in Fig. 29 and Fig. 31, when the back plate 2 is not bent so much, the headrest 44 moves backward and does not obstruct the occupant. When the backboard 2 is bent from this state, the headrest 44 moves forward as shown in FIGS. 30 and 32, and can support the head of the seated person.

Note that the support member 44 is not limited to a headrest that supports the head of a seated person. For example, as shown in Fig. 39 and Fig. 40, it may be possible to support the seated person from the scapula to the head. The support members 44 of Fig. 39 and Fig. 40 are, for example, if the user leans on the backboard 2 while operating the personal computer, the occupant raises the upper back slightly to see the monitor. It looks like this. Even in such a case, the upper body of the seated person can be lifted by the support body 57. In the above-described embodiment, the link member 45 is provided to operate the servo member 44 in conjunction with the bending of the back plate 2. However, the movement of the support member 44 is controlled by the bending of the back plate 2. It does not need to be linked to. The support member 44 may be fixed to the back plate 2 or, in some cases, an operation means for operating the support member 44 independently of the bending of the back plate 2 is provided. May be tilted.

Although not shown, an operation lever or the like is provided at a position where the occupant can easily operate, and displacement means 7 such as an adjusting screw 17, a cam plate 38, and links 40 and 41 use the operation lever or the like. It is also possible to operate it.

In addition, as a driving means of the displacement means 7, an electric motor for rotating the adjusting screw 17, the cam plate 38, the link 40, 41, etc. is adopted, and the electric motor is started and stopped by a switch operation. The displacement means 7 may be operated electrically.

In addition, a bag that expands and contracts with a fluid is provided as the displacement means 7, and the bag is connected to the second back frame 5 and the back plate 2, and a fluid such as air is injected or sucked into the bag. The bag may be expanded or contracted to tilt the second back frame 5, that is, to change the bending angle of the back plate 2.

Further, the present invention may be applied to a seat, and the bending angle of the seat plate may be adjusted. A seat frame, a front portion or a rear portion fixed to the seat frame, and a rear portion or the front portion capable of bending upward and downward; and a bending angle adjustment for changing a bending angle of the seat plate and fixing the bending angle. It may be a seat structure of a chair provided with a mechanism.

Further, the seat structure of the chair includes a seat plate having a front portion fixed to the seat frame and a rear portion capable of bending vertically, and a bending angle adjusting mechanism for changing a bending angle of the seat plate and fixing the bending angle. Alternatively, when the lower portion of the back plate 2 is fixed to the rear portion of the seat plate and the rear portion of the seat plate is bent downward, the back plate 2 may be tilted rearward following this.

Further, in the backrest structure of Fig. 1, the second back frame 5 is formed by connecting the two pipes by welding or the like with the connecting plate 12 of another member. It may be formed integrally. That is, the second back frame 5, the connection plate 12, and the bracket 12a may be integrally formed by, for example, metal die casting such as aluminum die casting. Also, it is not limited to one-piece molded products by metal die casting. It may be an integrally molded product made of resin or an integrally molded product made of a metal press.

In addition, the flexible back plate 2 and the back support structure that supports the back support member 61 with at least a portion connected to the back plate 2 with flexibility are shown in Fig. l to Fig. 12 have already been described as being practicable in the embodiment shown in FIGS. 13 to 45. Needless to say, the embodiment can be also performed in the embodiments shown in FIGS. That is, the backrest structure in which the backboard 2 is deformed in accordance with the posture when the seated person leans on the backboard 2 can be implemented alone, or the backboard 2 can be bent back and forth in the bending area 2 e. It can be carried out simultaneously with the leaning structure.

For example, the present invention can be applied to a chair without the bending angle adjusting mechanism 3, that is, a chair having a structure in which the back plate 2 is directly supported by the back support member 61. In these cases as well, the back plate 2 can be easily deformed and deformed and follow the movement of the occupant, making it easy to lean on.The simple structure increases the degree of freedom of deformation of the back plate 2. This is similar to the above-described backrest structure in that the number of parts can be reduced and the number of parts is not increased.

For example, one set of resin back support members 61 in which the amount of a reinforcing agent such as glass fiber is adjusted so that only the portion connected to the upper portion of the back plate 2 exhibits flexibility is prepared. The lower part of the back plate 2 is fixed and supported at the relatively rigid part of the member 61, while the upper part of the back plate 2 is rotatable and slidable on the tip of the flexible back support member 61. The left and right back support members 61 may be separately tilted to deform the backrest according to the posture of the seated person leaning on the back. Here, the back support members 61 may be tilted independently on the left and right, or may be connected to each other by a lateral reinforcing member on the side of the mounting portion to the seat receiving member 8 rather than the portion for fixing the lower portion of the seat. And may be integrated. For example, the first back frame 1 tiltably attached to the seat receiving member 8 with the displacement means 7 omitted, and the second back frame 5 tiltably attached to the first back frame 1 A back support member 61 having a back plate bending region 2 e, a back plate upper portion 2 a positioned above the back plate bending region 2 e, and a lower position positioned below the back plate bending region 2 e And a back plate 2 having a back plate lower portion 2b fixed to the first back frame 1 and an upper end of the second back frame 5 connected to the back plate upper portion 2a while absorbing these relative displacements. The connecting means 6 may be provided. In this case, the backboard bending area 2e is deformed, and the backboard upper section 2a is tilted in the front-back direction with respect to the backboard lower section 2b. 2 can be bent, and at least the upper portion 2a of the backboard 2 can be deformed. Here, by forming the second back frame 5 from a flexible resin, the back plate 2 can be further deformed so as to be twisted in a horizontal plane. This example is shown in Fig. 44 and Fig. 45. When the occupant leans on the backboard 2, the second back frame 5 bends the upper part 2 a of the backboard 2. Also, at the same time, the second back frame 5 bends following the posture of the seated person, so that the upper portion 2a of the back plate 2 can easily be deformed following the posture of the seated person. That is, also in this case, the deformation of the back plate 2 is easy, the deformation is easy to follow the movement of the occupant, and the sitting comfort is improved, and the degree of freedom of the deformation of the back plate 2 is simple. This is similar to the above-described backrest structure in that the number of parts can be increased and the number of parts is not increased.

Claims

The scope of the claims

1. A back having at least one first back frame tiltably attached to the seat receiving member and at least one second back frame tiltably mounted to the first back frame. A back plate having a support member, a back plate bending region, a back plate upper portion located above the back plate bending region, and a back plate lower portion located below the back plate bending region; One of a back plate upper portion and the back plate lower portion is fixed to the first back frame, and one of the other is supported by the second back frame, thereby deforming the back plate bending region. By tilting the other in the front-to-rear direction with respect to the one, the back plate can be bent as a whole, and the tilt angle of the second back frame with respect to the first back frame is adjusted to adjust the tilt angle of the second back frame. Changing the bending angle of the back plate and bending A chair backrest structure comprising a bending angle adjusting mechanism for fixing a bending angle.

2. The lower part of the back plate is fixed to the first back frame, and the upper part of the back plate is tiltable in the front-rear direction. The lower end of the bending angle adjusting mechanism is connected to the first back frame. The second back frame, the upper end of which can be tilted in the front-rear direction around the connection point; and a connection for connecting the upper end of the second back frame to the upper part of the back plate while absorbing these relative displacements. Means, and a distance between the first back frame and the second back frame provided at a position away from the connection point between the first back frame and the second back frame. 2. The backrest structure for a chair according to claim 1, wherein the backrest structure is provided with a displacement means for changing the distance.

3. A backrest structure for a chair, comprising: a deformable back plate; and at least one back support member having at least a portion connected to the back plate formed of a flexible resin. .

4. The backrest structure for a chair according to claim 3, further comprising a connecting means for connecting an upper end of the back support member to an upper portion of the back plate while absorbing these relative displacements.

5. A back support member having at least one first back frame tiltably attached to the seat receiving member and at least one second back frame tiltably mounted to the first back frame. And the backboard bending area, and from the backboard bending area A back plate having a back plate upper portion also located on the upper side, a back plate lower portion located below the back plate bending region and fixed to the first back frame, and a second back frame. Connecting means for connecting the upper end to the upper part of the backboard while absorbing these relative displacements, by deforming the bent area of the backboard and tilting the upper part of the backboard forward and backward with respect to the lower part of the backboard. The back plate is bendable as a whole, and at least the upper portion of the back plate is deformable, and the second back frame is formed of a flexible resin. Characterized chair backrest structure.

6. A back support member having at least one first back frame tiltably attached to the seat receiving member and at least one second back frame tiltably mounted to the first back frame. A back plate bending region; a back plate upper portion located above the back plate bending region; and a back plate bending region located below the back plate bending region and

A back plate having a back plate fixed to the back frame of the back plate, wherein the back plate bending region is deformed to tilt the upper portion of the back plate in the front-rear direction with respect to the lower portion of the back plate. A bending angle adjustment mechanism that changes the bending angle of the back plate and fixes the bending angle by adjusting the tilt angle of the second back frame with respect to the first back frame. The second back frame having a lower end connected to the first back frame, and an upper end capable of tilting in the front-rear direction about the connection point; Connecting means for connecting the upper end of the back frame to the upper portion of the back plate while absorbing these relative displacements; and a position separated from the connection point between the first back frame and the second back frame. The first back frame provided in the Displacement means for changing the distance from the second back frame is provided, and at least the upper part of the back plate is deformable, and the second back frame is made of a flexible resin. A chair backrest structure characterized by being formed.

7. The displacement means has an adjustment screw provided on one of the first back frame and the second back frame, and a screw hole provided on one of the other, and into which the adjustment screw is inserted. 7. The female screw member according to claim 2, further comprising: a female screw member; and angle changing means for changing at least one angle of the adjusting screw and the female screw hole member in a vertical direction. Chair backrest structure.

8. The connecting means includes a shaft portion having a circular contour formed at least at an upper end of the second back frame; a connecting portion rotatable relative to the shaft portion and slidable in the axial direction; 3. The vehicle according to claim 2, further comprising: a shaft supporting means for attaching a connecting portion to the back plate so as to be rotatable in a vertical direction, wherein the connecting portion has a length that does not drop off from the shaft portion. The chair backrest structure according to any one of paragraphs 4, 5, and 6.

9. The connecting means includes a shaft portion having a circular contour formed at least at an upper end of the second back frame, and a shaft portion provided on the back surface of the back plate, wherein the shaft portion is inserted from below and the shaft portion is provided. A shaft bearing having an inlet formed to allow inclination of the shaft portion, and a member provided above the shaft bearing and defining a space for allowing movement of a tip of the shaft portion. The chair backrest structure according to any one of claims 2, 4, 5, and 6.

10. The range of claim 1, wherein at least one slit is formed in the bent region of the back plate so that the upper portion of the back plate or the lower portion of the back plate can be tilted in the front-rear direction. Item 7. The chair backrest structure according to any one of items 5, 5 and 6.

11. A support member for assisting a backrest is rotatably attached to an upper end of the back plate, and the support member and the first back frame are connected by a link, and the support member is interlocked with the bending of the back plate. The backrest structure for a chair according to any one of claims 1, 2, 5, and 6, wherein the support member is rotated.

12. The backrest structure for a chair according to any one of claims 3 to 6, wherein the resin is nylon with glass.