A folding chair formed of cardboard

Abstract

Provided is a folding chair formed of cardboard with improved strength. 【Solution means】The folding chair includes a pair of flat portions 110 and 120 arranged to face each other in a first direction, a first folding portion 130 that connects one side of the pair of flat portions and can be folded inside the pair of flat portions via a fold line along one side, a second folding portion 140 that connects the other sides of the pair of flat portions and can be folded inside the pair of flat portions via a fold line along the other side, a seat portion joined to the upper end of the first flat portion, where the tip portion of the seat portion engages with the second flat portion when the pair of flat portions are separated, and a bending member in which at least three plate-like portions having a size corresponding to the width between the opposing inner surfaces of the pair of flat portions are connected via fold lines and are located between the opposing inner surfaces of the pair of flat portions.

Description

Technical Field

[0001] The technology disclosed in this specification relates to a folding chair formed of cardboard.

Background Art

[0002] Conventionally, folding chairs formed of cardboard have been known. For example, a folding chair includes a foldable square tube and a seat plate arranged to cover the upper end opening of the square tube (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the conventional folding chair, there has been room for improvement in terms of strength.

[0005] This specification discloses a technology capable of solving at least a part of the above-described problems.

Means for Solving the Problems

[0006] The technology disclosed in this specification can be realized in the following forms.

[0007] (1) The folding chair disclosed in this specification is a folding chair formed of cardboard, and includes a cylindrical base having a first flat portion and a second flat portion disposed opposite to each other in a first direction, a first folding portion that connects one side of the first flat portion and the second flat portion and is foldable inside the base through a fold along the one side, and a second folding portion that connects the other side of the first flat portion and the second flat portion and is foldable inside the base through a fold along the other side; a seat portion that covers one opening of the base, wherein a proximal end portion of the seat portion is joined to one end of the first flat portion, and a distal end portion of the seat portion engages with the second flat portion in a state where the first flat portion and the second flat portion are separated from each other in the first direction; and a bending member located inside the base and having a size corresponding to an inner wall surface of the first flat portion, the at least three plate-like portions being connected through folds. According to this folding chair, by having the first folding portion, the second folding portion, and the bending member, the strength of the folding chair formed of cardboard can be improved.

[0008] (2) In the above folding chair, which is a folding chair formed of cardboard as described in (1), the at least three plate-like portions include a first plate-like portion and a pair of second plate-like portions respectively connected to both ends of the first plate-like portion, and the bending member may be configured to be bent at a fold between the first plate-like portion and one of the second plate-like portions and at a fold between the first plate-like portion and the other second plate-like portion, and the free ends of the pair of second plate-like portions are joined together to form a triangular tube shape. According to this configuration, since the bending member has a triangular tube shape, the bending member is more stably held inside the base.

[0009] (3) In the above folding chair, which is a folding chair formed of the cardboard described in (2), the bending member may be arranged in the base such that the outer surface of the first plate-like portion faces the inner surface of the first flat portion, and the free ends of the pair of second plate-like portions face the inner surface of the second flat portion. According to this configuration, the bending member can be easily attached to and detached from the base.

[0010] (4) In the above folding chair, which is a folding chair formed of the cardboard described in (2) or (3), the bending member may have a first notch extending from one end of the free end of one of the second plate-like portions to the other side, and a second notch extending from one end of the free end of the other second plate-like portion to the other side. According to this configuration, the first notch and the second notch can prevent, for example, the first plate-like portion and the second plate-like portion from interfering with the second flat portion when the bending member is arranged in the base.

[0011] (5) In the above folding chair, which is a folding chair formed of the cardboard described in (1), the seat portion may be foldable via a folding line parallel to the boundary between the seat portion and the first flat portion, and in a state where the first flat portion and the second flat portion are close to each other, the inner surface of the seat portion may face the outer surface of the second flat portion. According to this configuration, by the inner surface of the seat portion facing the outer surface of the second flat portion, one surface of the folded chair can be made flat.

[0012] (6) In the above folding chair, which is a folding chair formed of the cardboard described in (1) or (2), the width of the plate-like portion may be longer than the opposing distance between the inner wall surfaces of the first flat portion and the second flat portion in a state where the first flat portion and the second flat portion are separated. According to this configuration, the strength of the chair formed of cardboard can be further improved.

[0013] (7) In the folding chair described above, which is a folding chair formed of the cardboard described in (6), the surface of the plate-shaped portion that contacts the seat portion may be configured to have recesses at both ends. According to this configuration, the assembly of the folding chair can be made easier.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Mode for Carrying Out the Invention

[0015] A. Embodiment: A-1. Configuration of Chair 1: FIG. 1 is an external view of the chair 1 in the present embodiment. FIG. 2 is a bottom view of the chair 1 in the present embodiment. FIG. 3 is an external view of the seat portion 15 of the chair 1 in the present embodiment unfolded. In FIGS. 1 to 3, XYZ axes orthogonal to each other for specifying directions are shown. In this specification, for convenience, the positive direction of the Z axis is referred to as upward, the negative direction of the Z axis is referred to as downward, the positive direction of the X axis is referred to as forward, the negative direction of the X axis is referred to as backward, the positive direction of the Y axis is referred to as rightward, and the negative direction of the Y axis is referred to as leftward. The front-rear direction is an example of the first direction. The chair 1 may actually be installed in a direction different from such a direction. The same applies to FIGS. 4 and later.

[0016] The chair 1 is a foldable chair formed of cardboard. Specifically, as shown in FIG. 1, the chair 1 has a substantially rectangular parallelepiped shape. The bottom surface of the chair 1 is open (see FIG. 2). The chair 1 includes a chair body 10 and a bending member 20 as shown in FIGS. 2 and 3. The chair body 10 forms the external appearance of the chair 1. The inside of the chair body 10 is a cavity (hereinafter referred to as "internal space R"). The bending member 20 is disposed in the internal space R of the chair body 10. The bending member 20 is plate-shaped. The bending member 20 is a member having a plurality of bent portions.

[0017] (Configuration of the chair body 10) The chair body 10 includes a base 11 and a seat portion 15. The base 11 has a square tube shape that is open in the vertical direction (see FIGS. 2 and 3). The seat portion 15 is provided on the base 11 so as to be able to open and close the upper opening of the base 11.

[0018] The base 11 has a front side surface portion 110, a rear side surface portion 120, a left side surface portion 130, and a right side surface portion 140. The front side surface portion 110 is an example of the first flat portion. The rear side surface portion 120 is an example of the second flat portion. The left side surface portion 130 is an example of the first folding portion. The right side surface portion 140 is an example of the second folding portion.

[0019] The front side face 110 and the rear side face 120 are plate-shaped members of the same size. The front side face 110 and the rear side face 120 are flat rectangles. In this embodiment, the front side face 110 and the rear side face 120 face each other in the front-rear direction of the chair body 10. In the assembled state of the chair 1, the front side face 110 and the rear side face 120 are spaced apart in the front-rear direction.

[0020] The left side face 130 connects the left side (an example of "one side") of the front side face 110 and the left side of the rear side face 120. The right side face 140 connects the right side (an example of "the other side") of the front side face 110 and the right side of the rear side face 120. The left side face 130 and the right side face 140 are a pair of plate-shaped members of the same size. The left side face 130 and the right side face 140 are rectangular. In this embodiment, the left side face 130 and the right side face 140 face each other in the left-right direction of the chair body 10.

[0021] The left side face 130 has a left folding line 130F that is a fold in the center in the front-rear direction. The left folding line 130F is linearly formed along the up-down direction of the left side face 130. The left side face 130 is folded into the internal space R (right direction) of the chair 1 via the left folding line 130F. The right side face 140 also has a right folding line 140F that is a fold in the center in the front-rear direction. The right folding line 140F is linearly formed along the up-down direction of the right side face 140. The right side face 140 is folded into the internal space R (left direction) of the chair 1 via the right folding line 140F.

[0022] The seat portion 15 of the chair body 10 has an upper seat portion 150 and a lower seat portion 160. The upper seat portion 150 is an example of a seat portion. The upper seat portion 150 and the lower seat portion 160 are arranged in order from above in the upper opening of the base 11 (see FIG. 1). The upper seat portion 150 and the lower seat portion 160 are rectangles of the same size.

[0023] The front side edge of the upper seat portion 150 is connected to the side edge above the front side surface 110 (an example of "the upper end of the first flat portion") as shown in FIG. 3. A folding line L15 is formed at the connection portion between the upper side edge of the front side surface 110 and the front side edge of the upper seat portion 150. Due to the folding line L15, the upper seat portion 150 can be folded with respect to the front side surface 110. The inner (lower) side of the upper seat portion 150 has a groove (hereinafter referred to as "the folding line 150F") parallel to the folding line L15.

[0024] [[ID=z3]] An insertion portion 152 extends from the rear side (the side opposite to the front side surface 110) of the upper seat portion 150. The rear side edge of the upper seat portion 150 (an example of "the tip portion of the seat portion") is connected to one side edge of the insertion portion 152 (the upper side edge in FIG. 1). A folding line L17 is formed at the connection portion between the rear end of the upper seat portion 150 and the side edge of the insertion portion 152. Due to the folding line L17, the insertion portion 152 can be folded with respect to the upper seat portion 150. In the present embodiment, the insertion portion 152 is rectangular. The longitudinal length of the insertion portion 152 connected to the upper seat portion 150 is half of the length of the side edge of the upper seat portion 150 on the side of the insertion portion 152. The side edge of the insertion portion 152 is located at the center of the side edge of the upper seat portion 150.

[0025] The rear side edge of the lower seat portion 160 is connected to the upper side edge of the rear side surface 120 as shown in FIG. 3. A folding line L16 is formed at the connection portion between the upper side edge of the rear side surface 120 and the rear side edge of the lower seat portion 160. Due to the folding line L16, the lower seat portion 160 can be folded with respect to the rear side surface 120.

[0026] The insertion part 162 extends from the front of the lower seat part 160 (the side opposite to the rear side surface 120). The front side edge of the lower seat part 160 is connected to one side edge of the insertion part 162 (the upper side edge in the state where the chair body 10 is folded). A folding line L18 is formed at the connection part between the front end of the lower seat part 160 and the side edge of the insertion part 162. Due to the folding line L18, the insertion part 162 can be folded with respect to the lower seat part 160. In the present embodiment, the insertion part 162 is rectangular. The longitudinal length of the insertion part 162 connected to the lower seat part 160 is the same as the lateral length of the lower seat part 160. In the assembled state of the chair body 10, the insertion part 162 is inserted into the internal space R of the chair body 10 along the inner surface of the front side surface 110 (see FIG. 8). Thereby, the lower seat part 160 closes the upper opening of the base 11.

[0027] The lower seat part 160 (or the rear side surface 120) has a slit h1 which is a horizontally long hole along the folding line L16. The length of the hole in the lateral direction of the slit h1 is the same as the lateral length of the insertion part 152. In the assembled state of the chair body 10, the insertion part 152 is inserted into the slit h1 (see FIG. 1). Thereby, the upper seat part 150 is arranged to cover the upper surface of the lower seat part 160. In the present embodiment, the slit h1 is formed at the center in the lateral direction of the folding line L16.

[0028] Note that the seat part 15 has a hole h2 penetrating from the outside to the inside rearward as shown in FIG. 1. In the present embodiment, the hole h2 is semi-circular. The hole h2 has a hole h21 and a hole h22. The hole h21 is formed in the upper seat part 150. The hole h21 is along the folding line L17. The hole h22 is formed in the lower seat part 160. The hole h22 is along the folding line L16. The hole h22 and the slit h1 are connected.

[0029] (Expansion view of the chair body 10) FIG. 4 is an expansion view of the outer surface side of the chair body 10. The chair body 10 is formed by a single cardboard. The flute direction of the cardboard forming the chair body 10 is the vertical direction.

[0030] The base 11 of the unfolded (before formation) chair body 10 is rectangular. The unfolded base 11 is arranged in the order of a right side face portion 140, a front side face portion 110, a left side face portion 130, and a rear side face portion 120 from left to right. A folding line L11 is formed between the right side face portion 140 and the front side face portion 110. Due to the folding line L11, the right side face portion 140 and the front side face portion 110 are foldable. A folding line L12 is formed between the front side face portion 110 and the left side face portion 130. Due to the folding line L12, the front side face portion 110 and the left side face portion 130 are foldable. A folding line L13 is formed between the left side face portion 130 and the rear side face portion 120. Due to the folding line L13, the left side face portion 130 and the rear side face portion 120 are foldable.

[0031] Fitting portions 122 and 142 are arranged on the side edges at both ends of the unfolded base 11. The fitting portion 122 and the fitting portion 142 are arranged at positions shifted from each other in the vertical direction. A folding line L14a is formed at the connecting portion between the left side of the fitting portion 122 and the right side of the rear side face portion 120. Due to the folding line L14a, the fitting portion 122 is foldable with respect to the rear side face portion 120. A folding line L14b is formed at the connecting portion between the right side of the fitting portion 142 and the left side of the right side face portion 140. Due to the folding line L14b, the fitting portion 142 is foldable with respect to the right side face portion 140. The fitting portion 122 has a notch 122n. The notch 122n extends downward from the upper end of the fitting portion 122. The fitting portion 142 has a notch 142n. The notch 142n extends upward from the lower end of the fitting portion 142.

[0032] When each folding line (L11, L12, L13, L14a, L14b) of the base 11 is valley-folded and the notch 122n of the fitting portion 122 and the notch 142n of the fitting portion 142 are engaged with each other, a square tubular base 11 is formed (see FIG. 3).

[0033] In the unfolded chair body 10, as shown in FIG. 4, the upper side edge above the front side surface portion 110 of the base 11 and the lower side edge of the upper seat portion 150 (the front side edge in FIG. 1) are connected. Also, the upper side edge above the rear side surface portion 120 of the base 11 and the lower side edge of the lower seat portion 160 (the rear side edge in FIG. 1) are connected.

[0034] Before forming the chair body 10 (in the unfolded state), the respective lengths (width W11) in the left - right direction (front - rear direction) of the right side surface portion 140, the front side surface portion 110, the left side surface portion 130, and the rear side surface portion 120 are the same. Also, the respective lengths (width W12) in the up - down direction of the right side surface portion 140, the front side surface portion 110, the left side surface portion 130, and the rear side surface portion 120 are the same. The width W13 in the left - right direction of the lower seat portion 160 of the chair body 10 is the same as the width W11. The width W14 in the up - down direction (front - rear direction in FIG. 1) of the lower seat portion 160 is shorter than the width W11 and the width W13. Also, in this embodiment, the width W15 between the folding line 150F and the bending line L15 of the upper seat portion 150 is approximately the same as the thickness of four sheets of cardboard. Also, the lengths (width W16) in the up - down direction of the insertion portion 152 and the insertion portion 162 are the same.

[0035] (Configuration of the bending member 20) As shown in FIGS. 2 and 3, the bending member 20 has a left plate - like portion 210, a middle plate - like portion 220, and a right plate - like portion 230. The left plate - like portion 210, the middle plate - like portion 220, and the right plate - like portion 230 are rectangular shapes of the same size. Note that the middle plate - like portion 220 is an example of a first plate - like portion. The left plate - like portion 210 and the right plate - like portion 230 are examples of a pair of second plate - like portions.

[0036] FIG. 5 is a developed view of the bending member 20. As shown in FIG. 5, the bending member 20 is formed from a single piece of cardboard. The direction of the flutes of the cardboard forming the bending member 20 is the vertical direction. The developed bending member 20 is arranged in order from left to right as a left plate-like portion 210, a middle plate-like portion 220, and a right plate-like portion 230. A bending line L21, which is a fold line, is formed between the left plate-like portion 210 and the middle plate-like portion 220. A bending line L22, which is a fold line, is formed between the middle plate-like portion 220 and the right plate-like portion 230. The left plate-like portion 210 and the middle plate-like portion 220 can be bent by the bending line L21. The middle plate-like portion 220 and the right plate-like portion 230 can be bent by the bending line L22. Note that the left and right sides of the bending member 20 (the left side of the left plate-like portion 210 and the right side of the right plate-like portion 230 in FIG. 5) are an example of free ends.

[0037] In the present embodiment, the lateral width W21 of each of the plate-like portions 210, 220, 230 is approximately the same length as the width W11 of the left side surface portion 130 of the chair body 10 when it is unfolded. Also, the vertical width W22 of each of the plate-like portions 210, 220, 230 is the same length as the width W12 of the left side surface portion 130 of the chair body 10 when it is unfolded.

[0038] The left plate-like portion 210 has rectangular recesses 210a and 210b at the upper ends of both corners. Similarly, the middle plate-like portion 220 has recesses 220a and 220b, and the right plate-like portion 230 has recesses 230a and 230b. Each of the recesses (210a, 210b, 220a, 220b, 230a, 230b) has the same shape. Note that the recess 210a is an example of a first notch. The recess 230b is an example of a second notch.

[0039] The vertical length of each of the recesses (210a, 210b, 220a, 220b, 230a, 230b) at both ends of the upper end of each of the plate-like portions (210, 220, 230) is the width W26, and the horizontal length is the width W27. The width W26 is longer than the vertical width W16 of the insertion portion 152 of the upper seat portion 150. The width W27 is longer than the length in the thickness direction of the cardboard of the chair body 10.

[0040] The bent member 20 is formed by bending at the location between the bending line L21 and the bending line L21. In the present embodiment, the bent member 20 is mountain-folded along the bending line L21 and valley-folded along the bending line L22. The bent member 20 is disposed in the internal space R of the chair body 10 with each recess (210a, 210b, 220a, 220b, 230a, 230b) facing upward (see FIG. 3). The bent member 20 disposed in the internal space R of the chair body 10 forms an N shape when viewed from below the chair 1.

[0041] A-2. Folding of the chair 1: FIGS. 6 and 7 are external views of the folded chair body 10 in the present embodiment. FIGS. 8 and 9 are external views of the chair body 10 during the folding process in the present embodiment. That is, FIG. 6 is an external view of the folded chair body 10 as viewed from the front direction. FIG. 7 is an external view of the folded chair body 10 as viewed from the rear direction (opposite side of FIG. 6). FIGS. 8 and 9 are external views of the chair body 10 during an intermediate process among the steps from the assembled chair 1 shown in FIG. 1 to the folded chair body 10 shown in FIG. 6.

[0042] As shown in FIG. 6, the folded chair body 10 exposes the entire surface of the front side face portion 110 forward. As shown in FIG. 7, the folded chair body 10 exposes a part of the rear side face portion 120, a part of the lower seat portion 160, and a part of the upper seat portion 150 rearward. The folded chair body 10 exposes a part of the upper seat portion 150 upward. The upper seat portion 150 is folded by the folding line 150F.

[0043] The assembled chair 1 can be folded as shown in FIG. 6 (FIG. 7) through the states shown in FIG. 8, FIG. 3, and FIG. 9 from the state shown in FIG. 1. The folding procedure of the chair 1 is as follows.

[0044] As shown in FIG. 8, the insertion portion 152 of the upper seat portion 150 is taken out from the slit h1 of the rear side surface portion 120 (lower seat portion 160). The side on the rear side of the upper seat portion 150 is separated from the rear side surface portion 120 (lower seat portion 160). Thereby, the lower seat portion 160 is exposed above the chair body 10. Note that due to the hole h2, the insertion portion 152 of the upper seat portion 150 can be easily taken out from the slit h1 of the rear side surface portion 120.

[0045] As shown in FIG. 3, the insertion portion 162 of the lower seat portion 160 is taken out from the internal space R of the chair body 10. The side on the front side of the lower seat portion 160 is separated from the front side surface portion 110. Thereby, the internal space R of the chair body 10 is exposed.

[0046] Take out the bending member 20 arranged on the chair 1 from the internal space R of the chair body 10. Thereby, the left side surface portion 130 of the chair body 10 can be folded further toward the internal space R side of the chair body 10 via the left folding line 130F. Also, the right side surface portion 140 of the chair body 10 can be folded further toward the internal space R side of the chair body 10 via the right folding line 140F. Thereby, the left side surface portion 130 and the right side surface portion 140 of the chair body 10 are folded as shown in FIG. 9.

[0047] As shown in FIG. 9, the lower seat portion 160 of the chair body 10 is bent rearward by the bending line L16 and further bent downward. The outer surface of the lower seat portion 160 (the surface that was in contact with the upper seat portion 150 in FIG. 1) is in contact with the outer surface of the rear side surface portion 120 (see FIG. 7).

[0048] As shown in FIGS. 6 and 7, the upper seat portion 150 of the chair body 10 is bent rearward by the bending line L15. Further, the upper seat portion 150 is bent downward via the folding line 150F. The inner surface of the upper seat portion 150 folded via the folding line 150F (the surface that was in contact with the lower seat portion 160 in FIG. 1) is in contact with the surface of the lower seat portion 160 (the surface on the internal space R side in FIG. 1). The inner surface of the upper seat portion 150 faces the outer surface of the rear side surface portion 120.

[0049] A-3. Effects of this Embodiment: According to this embodiment, by having the left side surface 130, the right side surface 140, and the folding member 20, the strength of the foldable chair 1 formed of cardboard can be improved.

[0050] When the chair body 10 is assembled, the upper side surface of the left side surface 130 and the left side surface of the lower seat portion 160 face each other (see FIG. 1). Here, as shown in FIG. 4, the width W14 of the left side surface of the lower seat portion 160 is shorter than the width W11 of the upper side surface of the left side surface 130. Due to this difference in width, when the chair body 10 is assembled, the left side surface 130 of the chair body 10 is folded inward of the chair body 10 along the left folding line 130F. Since the left side surface 130 and the right side surface 140 have the same shape, the relationship between the right side surface 140 and the lower seat portion 160 is the same. Also, since the lower seat portion 160 and the upper seat portion 150 have the same shape, the relationship between the upper seat portion 150, the left side surface 130, and the right side surface 140 is the same. The length of the assembled chair 1 in the front-rear direction is the width W14. The length of the chair 1 in the left-right direction is the width W11. In the assembled chair body 10, the left side surface 130 and the right side surface 140 are folded into the internal space R in the left-right direction by the left folding line 130F and the right folding line 140F. Most of the upper side edge of the base 11 is in contact with the inner surface of the seat portion 15 (the inner surface of the lower seat portion 160). Thereby, the strength of the chair body 10 in the up-down direction is improved. Also, the left side surface 130 and the right side surface 140 extend in a direction different from both the front-rear direction and the left-right direction with respect to the horizontal direction of the chair body 10. Thereby, the stress in the left-right direction and the front-rear direction with respect to the chair body 10 can be dispersed. Therefore, the strength of the chair body 10 is improved.

[0051] In this embodiment, the upper seat portion 150 can be folded along a folding line 150F parallel to the boundary between the upper seat portion 150 and the front side face 110. When the front side face 110 and the rear side face 120 are close to each other, the inner surface of the upper seat portion 150 may face the outer surface of the rear side face 120. According to this configuration, since the inner surface of the upper seat portion 150 faces the outer surface of the rear side face 120, the front side face 110 of the folded chair 1 can be made flat. When the chair 1 is in a folded state, the entire surface of the front side face 110 is exposed. Therefore, the surface of the front side face 110 can secure the maximum space for describing illustrations, messages, and the like.

[0052] In this embodiment, the width W21 of each of the plate-like portions 210, 220, 230 may be longer than the width W14 of the inner surfaces of the front side face 110 and the rear side face 120 facing each other in a state where the front side face 110 and the rear side face 120 are separated from each other. According to this configuration, the strength of the chair 1 formed of cardboard can be further improved.

[0053] The lateral width W21 of each of the plate-like portions 210, 220, 230 of the bending member 20 is longer than the lateral width W14 of the chair body 10. When each of the plate-like portions 210, 220, 230 is disposed in the internal space R of the chair body 10, it contacts the inner surface of the front side face 110 and the inner surface of the rear side face 120 in the front-rear direction. At this time, due to the width W21, each of the plate-like portions 210, 220, 230 is not perpendicular to the inner surface of the front side face 110 and the inner surface of the rear side face 120. Thereby, the stress in the lateral direction and the front-rear direction with respect to the chair 1 can be further dispersed. As a result, the strength of the chair body 10 is improved.

[0054] In this embodiment, the surfaces of each of the plate-like portions 210, 220, 230 that contact the upper seat portion 150 may be configured to have recesses (210a, 210b, 220a, 220b, 230a, 230b) at both ends. According to this configuration, the assembly of the chair 1 can be made easier.

[0055] The vertical width W26 of each of the concave portions (210a, 210b, 220a, 220b, 230a, 230b) of the bending member 20 is longer than the vertical width W16 of the insertion portion 152 of the upper seat portion 150. The width W27 is longer than the length in the thickness direction of the cardboard of the chair body 10. Thereby, when the bending member 20 is disposed in the internal space R of the chair body 10, the bending member 20 does not interfere with the insertion portion 152 and the insertion portion 162 due to each of the concave portions (210a, 210b, 220a, 220b, 230a, 230b). That is, the chair body 10 and the bending member 20 do not interfere with each other, and the assembly of the chair 1 can be made easier. B. Modification example: The technology disclosed in this specification is not limited to the embodiments described by the above description and drawings, and includes various aspects such as the following, for example.

[0056] The configuration of the chair 1 in the above embodiment is merely an example, and can be variously modified. In the above embodiment, the chair body 10 is formed of a single cardboard, but may be formed of a plurality of cardboards. Further, the bending member 20 is formed of a single cardboard, but may be formed of a plurality of cardboards. Further, the chair body 10 and the bending member 20 may be formed of a single cardboard.

[0057] The front side surface portion 110, the rear side surface portion 120, the left side surface portion 130, and the right side surface portion 140 of the chair body 10 in the above embodiment are rectangular shapes of the same size, but may not be of the same size. They may not be of the same shape. For example, the front side surface portion 110 and the rear side surface portion 120 may have the same shape, and the left side surface portion 130 and the right side surface portion 140 may have the same shape but both may have a shape different from that of the front side surface portion 110.

[0058] The rear side surface portion 120 and the right side surface portion 140 of the chair body 10 in the above embodiment form the base 11 by engaging the fitting portion 122 and the fitting portion 142 when manufacturing the chair body 10, but the fitting method may be another method. For example, they may be joined with glue or the like. Further, they may be attached by a removable method such as a hook-and-loop fastener.

[0059] Although the bending member 20 in the above embodiment is composed of three plate-like portions (210, 220, 230), it is not particularly limited as long as there are three or more. For example, it may be four or five. Also, although the bending member 20 in the above embodiment is one member, it may also be a plurality of members.

[0060] Although the above embodiment described the folding procedure of the assembled chair 1, the folded chair 1 can be assembled by going through the reverse process.

[0061] The above embodiment is applicable not only to chairs but also to various cardboard assemblies used for other purposes, such as reception desks, desks, etc.

[0062] The cardboard material forming each member in the chair 1 of the above embodiment is merely an example, and each member may be formed of other cardboard materials (other than paper).

[0063] FIG. 10 is a bottom view of the chair 1 in a modified example. For the same configurations as those of the chair 1 in the above embodiment among the chairs 1 in the modified example, the description thereof will be omitted by attaching the same reference numerals. The appearance of the chair 1 in the modified example is the same as that of the chair 1 in the above embodiment (see FIG. 1).

[0064] In the chair 1 of the modified example, the bending method of the bending member 20 is different from that in the above embodiment. Specifically, the bending member 20 is valley-folded along the folding line L21 and valley-folded along the folding line L22. The bending member 20 disposed in the internal space R of the chair body 10 forms a substantially triangular triangular tube shape when viewed downward from the chair 1. In the modified example, the width W11 is about 1.15 times the width W14. This ratio may be 1.05 times or more and 1.20 times. The width W21 is about 1.1 times the width W14. This ratio may be 1.05 times or more and 1.20 times.

[0065] Even when the front face portion 110 and the rear face portion 120 of the chair 1 move in a direction approaching each other, the triangular prism shape of the bending member 20 is maintained. Specifically, the left plate-like portion 210 and the right plate-like portion 230 of the bending member 20 interfere with each other. Therefore, the height of the triangle formed by the bending member 20 is maintained. Therefore, the lengths of the front face portion 110 and the rear face portion 120 will not be shorter than the height formed by the bending member 20. That is, the rectangular parallelepiped shape of the chair 1 is maintained.

[0066] On the other hand, when the front face portion 110 and the rear face portion 120 of the chair 1 move in a direction away from each other, the three-dimensional shape of the bending member 20 is maintained. Specifically, when viewed from below the chair 1, the left plate-like portion 210 and the right plate-like portion 230 of the bending member 20 can move in a direction away from each other. That is, the length of the bending member 20 in the front-rear direction will not be shorter than the height of the triangle with the middle plate-like portion 220 as the base. That is, the bending member 20 is gripped by the front face portion 110 and the rear face portion 120 of the chair body 10.

Explanation of Reference Numerals

[0067] 1: Chair 10: Chair body 11: Base 15: Seat portion 20: Bending member 110: Front face portion 120: Rear face portion 122: Fitting portion 130: Left side face portion 130F: Left folding line 140: Right side face portion 140F: Right folding line 142: Fitting portion 150: Upper seat portion 150F: Folding line 152: Insertion portion 160: Lower seat portion 162: Insertion portion 210: Left plate-like portion 220: Middle plate-like portion 230: Right plate-like portion R: Internal space h1: Slit h21: Hole h22: Hole h2: Hole

Claims

1. A folding chair formed of cardboard, comprising: a cylindrical base having a first flat portion and a second flat portion disposed opposite to each other in a first direction; a first folding portion that connects one side of the first flat portion and the second flat portion and is foldable inside the base through a fold line along the one side; a second folding portion that connects the other sides of the first flat portion and the second flat portion and is foldable inside the base through a fold line along the other side, the base including the first folding portion and the second folding portion; a seat portion that covers one opening of the base, wherein a proximal end portion of the seat portion is joined to one end of the first flat portion, and a distal end portion of the seat portion engages with the second flat portion in a state where the first flat portion and the second flat portion are separated from each other in the first direction; a bent member located inside the base and having at least three plate-like portions connected through fold lines and having a size corresponding to an inner wall surface of the first flat portion; a folding chair comprising the above components.

2. The folding chair formed of cardboard according to Claim 1, wherein the at least three plate-like portions include a first plate-like portion and a pair of second plate-like portions respectively connected to both ends of the first plate-like portion; the bent member is bent at a fold line between the first plate-like portion and one of the second plate-like portions and at a fold line between the first plate-like portion and the other second plate-like portion, and free ends of the pair of second plate-like portions are joined together to form a triangular cylinder shape.

3. The folding chair formed of cardboard according to Claim 2, wherein the bent member is disposed inside the base such that an outer surface of the first plate-like portion faces an inner surface of the first flat portion and free ends of the pair of second plate-like portions face an inner surface of the second flat portion.

4. The folding chair formed of cardboard according to Claim 2 or Claim 3, wherein the bent member has a first notch extending from one end of a free end of one of the second plate-like portions to the other side and a second notch extending from one end of a free end of the other second plate-like portion to the other side.

5. The folding chair formed of cardboard according to Claim 1, wherein The seat portion is foldable via a folding line parallel to the boundary between the seat portion and the first flat portion, in a state where the first flat portion and the second flat portion are close to each other, the inner surface of the seat portion faces the outer surface of the second flat portion, Folding chair. **Claim 6** A folding chair formed of cardboard according to claim 1 or claim 2, wherein the width of the plate-like portion is longer than the opposing distance between the inner wall surfaces of the first flat portion and the second flat portion in a state where the first flat portion and the second flat portion are separated from each other, Folding chair. **Claim 7** A folding chair formed of cardboard according to claim 6, wherein the surface of the plate-like portion in contact with the seat portion has recesses at both ends, Folding chair.

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