Folding chair

Abstract

To provide a foldable chair having a simple design and excellent support stability of a seat.SOLUTION: A chair comprises a seat 1, a leg device 2 and a backrest 3. The leg device 2 is a four-leg type having horizontal upper frames 6, and the rear parts of the left and right upper frames 6 are connected by a beam material 8. The upper frames 6 are hidden below the seat 1, and the seat 1 is rotatably connected to a support bracket 29 disposed in the beam material 8. The chair can be used anywhere without discomfort due to that a member for folding is not viewed in a state that the seat 1 is leaned, and a four-leg type design is simple. The front and back two parts of the seat 1 are supported by the left and right upper frames 6 in a state that both ends are supported so as to secure high support strength without using a member such as a reinforcement frame.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a chair that can be folded by lifting and rotating the seat upward (flip-up rotation). [Background technology]

[0002] Folding chairs can be raised, rotated, and folded up, allowing multiple chairs to be nested one behind the other, making effective use of storage space and making them popular for meetings and lectures.

[0003] In folding chairs, the leg device that supports the seat has left and right leg frame bodies, and the leg frame bodies are often formed in an inverted Y shape (a human shape or a square shape) when viewed from the side, as shown in Patent Document 1, for example. In this case, the entire leg frame body is exposed on the left and right outside of the seat, and two beam members, one at the front and one at the back, are mounted on the left and right leg frame bodies, with the seat connected to the rear beam member and supported by the front beam member.

[0004] On the other hand, in Patent Documents 2 to 4, the leg frame is formed in a gate-like shape (a downward-opening U-shape) when viewed from the side, consisting of front and rear foot bodies and an upper frame connected to their upper ends, and the rear foot bodies protrude upward to form a back support, and the rear end of the seat is connected to a support shaft connected to the left and right back supports, while the front parts of the left and right upper frames are connected by left and right long beam members, and the beam members support the front part of the seat. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6436750 [Patent Document 2] Patent No. 4719902 [Patent Document 3] Patent No. 6076700 [Patent Document 4] Patent No. 6443962 Summary of the Invention [Problem to be solved by the invention]

[0006] In Patent Document 1, the left and right leg frames are entirely exposed to the outside of the seat, so the overall width is inevitably much larger than the width of the seat, which makes it difficult to make the chair compact. Also, because the leg frames are too conspicuous, the folding function is too obvious and gives people an impression of being ostentatious, which raises concerns that it may not fit in with the surrounding environment or atmosphere and be difficult to use in some places.

[0007] On the other hand, in Patent Documents 2 to 4, the front part of the leg frame is hidden under the seat, but the upward part at the rear of the seat is connected to the inside surface of the back support pillar, so the rear part of the leg frame and the back support pillar extend outward to the left and right of the seat.As a result, the left and right width of the chair has to be significantly larger than the left and right width of the seat, just like Patent Document 1, and there is the problem that it cannot be made compact, just like Patent Document 1.

[0008] Furthermore, the leg frame is conspicuous, just like in Patent Document 1, so the folding function is too obvious and it is not possible to prevent it from giving people an impression of being ostentatious.

[0009] The present invention was made against the backdrop of this current situation, and aims to disclose a four-legged folding chair that can be made compact without changing the seating area from conventional chairs, and that also has excellent design. [Means for solving the problem]

[0010] The present invention includes various configurations, typical examples of which are specified in each claim. The invention of claim 1 is as follows: The seat is connected to the leg device so that it can be raised and rotated with its rear part as a fulcrum. It In the folded state with the seat raised and rotated, multiple units can be nested front and back. It is possible , The leg device Upper and lower long front and rear legs A horizontal upper frame with a longitudinal length between the top ends of the butThe upper frame of the left and right leg frame bodies is connected to each other, and the left and right longitudinal beam members connect the upper frame of the left and right leg frame bodies only at the rear end portion. There are " In this basic configuration, " The upper frame is integrally connected to the front legs, and the front upper frame extends rearward from the upper ends of the front legs, and is arranged so as not to protrude beyond the left and right outer sides of the seat, A backrest is attached to a back support located behind the seat. " The structure is as follows.

[0011] The invention of claim 2 is the same as claim 1, " before When the seat is tilted forward, its left and right sides are supported by the upper frame. The structure is as follows.

[0012] The invention of claim 3 is the same as claim 1 or 2, "The rear portion of the seat is rotatably connected to the beam material, and when tilted forward, the portion in front of the beam material is supported by the left and right upper frames in a state where both ends are supported." The structure is as follows.

[0013] The invention of claim 4 is the same as claim 3, "The seat is connected to a support bracket that projects upward from the beam." The upward protrusion specified in claim 4 means that the upper end of the bearing part is higher than the beam material. Therefore, it includes both a position where it protrudes directly above the beam material in a side view and a position where it is inclined in a side view.

[0014] The invention of claim 5 is the same as claim 4, "The support bracket is formed from a rod material, and the upper end is horizontal, and the seat is connected to the horizontal portion." The structure is as follows.

[0015] The invention of claim 6 is in parallel with claim 1, The seat is connected to the leg device so that it can be raised and rotated with its rear part as a fulcrum. ItIn the folded state with the seat raised and rotated, multiple units can be nested front and back. It is possible , The leg device Upper and lower long front and rear legs Between the upper ends of the legs, a horizontal upper frame is connected to the left and right leg frame bodies. And, The seat is tilted forward and supported at both ends by the left and right upper frames. In this basic configuration, " The upper frame is integrally continuous with the front legs, and the front upper frame extends rearward from the upper ends of the front legs, and is arranged so as not to protrude outside the left and right sides of the seat, and the upper frame is arranged so that the entirety or most of it is located below the seat, A backrest is attached to a back support located behind the seat. " The structure is as follows.

[0016] The invention of claim 7 is any one of claims 1 to 6, "The above left and right hind legs Extends upward The back support is formed And left and right back The top ends of the pillars are connected together. The structure is as follows.

[0017] The invention of claim 8 is any one of claims 2 to 7, The seat has an outer shell that is rectangular in shape when viewed from above and has open top and bottom edges, an inner shell attached to the outer shell from above, and a cushioning material placed on the upper surface of the inner shell. The outer shell is a strength member, and its front horizontal section is supported by the left and right upper frames. The structure is as follows. [Effects of the Invention]

[0018] In each of the present inventions, the leg frame constituting the leg device is roughly U-shaped with an opening facing downwards when viewed from the side, and the rear of the seat is connected to this leg device. Me, legs It is easy to conceal most of the frame body below the seat.

[0019] Therefore, the leg device can be prevented from being exposed on the left and right outer sides of the seat. As a result, the chair can be made compact while maintaining its functionality without reducing the seating area, and the folding function is not overemphasized, resulting in a very simple and neat design despite being foldable. In short, the chair can have a simple appearance that blends in anywhere, similar to a non-folding four-legged chair with a fixed seat.

[0020] Furthermore, if the upper frame of the leg frame is in a horizontal position, the left and right upper frames must be arranged in a V-shaped position that widens forward in a plan view to allow nesting. However, because the beam material is connected only to the rear of the upper frame, the nesting pitch can be made smaller. This allows for effective use of space when storing. It also has a neat appearance even when folded.

[0021] In claim 2 Is, seat When the chair is tilted forward, the left and right sides are supported by the upper frame, which has the advantage of improving the stability of the seat when seated.

[0022] In addition, in each patent document, the connecting portion of the seat also serves as a load support portion, so it must be structured to ensure both smooth rotation and strength. 1, In 2, the weight of the seat can be supported by the leg frame, so by separating the connecting function from the supporting function, there is an advantage in that the freedom of design of the connecting part can be improved and smooth rotation can be ensured.

[0023] The seat can be connected to the leg frame with a member separate from the beam, but the structure can be simplified by connecting it to the beam as in claim 3. In this case, the seat can also be connected directly to the beam, but connecting it to a support bracket that protrudes upward as in claim 4 has the advantage of increasing installation precision and, because the pivot point of the seat is higher, the seat can be folded to a height that does not interfere with nesting.

[0024] From the standpoint of leg unit strength, it is preferable to position the beam as far forward as possible while still ensuring the required nesting pitch, but by configuring the support bracket in a rearward tilted position as in the embodiment, the beam can be positioned as far forward as possible while shifting the pivot point of the seat rearward, which allows the seat to be positioned as far back as possible in the folded state, thereby minimizing the nesting pitch while still ensuring the strength of the leg unit. It also makes it easy to raise and rotate the seat without its rear edge hitting the upper frame.

[0025] The support bracket can take various forms, but forming it into a U-shape using a rod such as a round bar as in claim 5 has the advantage of simplifying the structure while ensuring high strength. Another advantage is that the support bracket can be used to restrict left and right movement of the seat.

[0026] In a folding chair, the seat must be supported at two points, the front and the back, when the seat is folded down and unfolded. In each of the patent documents, the front part of the seat is supported by a beam member attached to the leg device. Therefore, when the seat is folded down, the entire beam member is exposed, which can be said to lack simplicity. Furthermore, because the beam member is in linear contact with the seat, there are concerns that a metal reinforcing frame will be necessary, as disclosed in patent documents 1 and 4.

[0027] In contrast, in the invention of claim 6, the seat is supported at both ends by the left and right upper frames, so no beam material is required to support the seat. This simplifies the structure and also gives the chair a simple appearance even when folded, contributing to improved marketability.

[0028] In addition, because the upper frame is located below the seat and the left-right spacing of the upper frame is smaller than the left-right width of the seat, the seat can be stably supported without taking special measures such as installing a metal reinforcing frame. This ensures the necessary strength while preventing the structure from becoming too complicated.

[0029] As in claim 7, by connecting the upper ends of the left and right back supports together, the entire chair frame becomes a robust structure, which has the advantage of ensuring high strength even when the left and right leg frames are connected by a single beam material.

[0030] Chair seats often have an outer shell made of synthetic resin as a strength member, but in the invention of claim 8, the outer shell is open at the top and bottom, allowing bending of the seat to improve comfort, while the long horizontal parts at the front and back function as beams to ensure high strength. In addition, it is possible to save on the material of the outer shell while ensuring the necessary strength, which also contributes to cost reduction.

[0031] In addition, when the cushion is folded, the square-shaped outer shell is exposed and the inner shell is visible through the opening, so if the inner shell has slits for promoting bending, these can be seen by people, letting people know that the cushion has excellent cushioning properties and improving its marketability. [Brief explanation of the drawings]

[0032] [Figure 1] 1A and 1B are external views of a chair according to an embodiment, in which (A) is a perspective view in an unfolded state, (B) is a perspective view in a folded state, and (C) is a partial rear perspective view. [Figure 2] (A) is a front view, (B) is a plan view, (C) is a bottom view, and (D) is a partially enlarged view of FIG. 1(B). [Figure 3] FIG. [Figure 4] (A) is a perspective view of the seat and the cushioning material separated, and (B) is a perspective view of the cushioning material turned upside down. [Figure 5] 1A is an exploded perspective view showing the connecting structure of the seat, FIG. 1B is a perspective view of the bearing portion, and FIG. 1C is a perspective view of the rear part of the outer shell. [Figure 6] 2(C) and (B) is a perspective view of the connecting portion of the seat with the beam material omitted. [Figure 7]4A is a cross-sectional view taken along line VIIA-VIIA in FIG. 4A, and FIG. 4B is a plan view showing the nesting state. [Figure 8] 10A and 10B are diagrams showing another embodiment, in which (A) is a side view in the middle of nesting, (B) is a bottom view of the chair alone, and (C) is a partial perspective view of yet another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0033] (1) Overview Next, embodiments of the present invention will be described with reference to the drawings. First, a first embodiment shown in FIGS.

[0034] As shown in FIG. 1, the chair includes a seat 1, a leg device 2 supporting the seat, and a backrest 3. The leg device 2 is Vertically long The chair is provided with left and right leg frame bodies 7, each having a longitudinal horizontal upper frame 6 connected between the upper ends of the front legs 4 and rear legs 5, and a single longitudinal beam member 8 connecting the upper frames 6 of the left and right leg frame bodies 7 only at the rear end portions thereof, and the seat 1 is connected to the beam member 8 so as to be rotatable up and down.

[0035] The front legs 4 and the upper frame 6 are integrally formed by bending a single metal pipe (steel or aluminum pipe), and the rear end of the upper frame 6 is welded to the rear legs 5. Back support columns 9 are integrally formed with the rear legs 5 and extend upward, and the upper ends of the left and right back support columns 9 are connected together via connecting rods 9a. The backrest 3 is made of plywood or resin, and is fixed to the back support columns 9 with two screws 10 on each side. In the case of a resin backrest 3, a synthetic resin positioning portion 3a can be provided on the back surface of the backrest, with either the inner periphery or the outer periphery, or both, protruding rearward, as shown by the dashed dotted line in Figure 1(C).

[0036] The left and right front legs 4 and the left and right hind legs 5 are inclined at a slight angle to the vertical so as to form a V shape in a front view. The front legs 4 and the hind legs 5 are also inclined at a slight angle to the vertical so as to form a V shape in a side view (the front legs 4 are inclined backward, and the hind legs 5 are inclined forward). By making the distance between the left and right front legs 4 wider than the distance between the left and right hind legs 5, multiple chairs can be nested front to back when the seat 1 is upright and rotated. Therefore, the left and right upper frames 6 form a V shape with a widened front in a plan view.

[0037] A horizontally swivelable caster 11 is attached to the bottom end of each of the legs 4, 5. Therefore, the bottom end of each of the legs 4, 5 is in a vertical position. Note that the caster 11 is not essential. There are also types that use synthetic resin or rubber ground contact bodies instead of casters.

[0038] The chair of this embodiment is equipped with a memo pad 12 as an optional accessory. As shown in Figure 1(B), memo pad 12 is attached to a frame member 13 that is fixed by welding to the right upper frame 6. Frame member 13 is bent in a crank shape, with a horizontal section 13a at its upper end. A bearing cap 14 that holds horizontal section 13a from below is fixed with a screw near one corner of memo pad 12, making memo pad 12 rotatable. Furthermore, a U-shaped position-maintaining member 15 that surrounds bearing cap 14 from below is fixed to horizontal section 13a of frame member 13 by welding.

[0039] Therefore, the memo stand 12 is maintained in a horizontal position by its underside abutting against the position maintaining member 15. The vertically raised position is maintained by a part of the memo stand 12 abutting against the upright portion of the frame member 13. Furthermore, the horizontal portion 13a of the frame member 13 is inclined so that it shifts inward to the left and right as it goes forward in a plan view. For this reason, as shown in Figure 7(B), the chair equipped with the memo stand 12 can be nested.

[0040] As shown in Figure 2(C), when the memo stand 12 is reclined to a horizontal position, it is tilted in a plan view (and bottom view) so that the distance from the backrest 3 increases as it moves away from the pivot point. When the seat 1 and memo stand 12 are reclined and in the unfolded state, the user of the chair sits down or leaves the seat by moving their body sideways from the side where the memo stand is not installed (the left side). In this embodiment, however, the space between the memo stand 12 and the backrest 3 widens toward the side where people enter and exit, preventing the memo stand 12 from getting in the way when the user moves their body sideways, allowing them to sit down or leave the seat smoothly.

[0041] Furthermore, since the memo pad 12 is located to the right of the seated person, the user will use a laptop computer or the like with their body twisted slightly to the side. However, if the memo pad 12 is tilted so that its left end is away from the backrest 3, as in the embodiment, the user's body will be directly facing the memo pad 12, allowing the user to use the laptop computer or the like in a natural position, which has the advantage of making it easier to use the laptop computer or the like.

[0042] 2(C) and (D), one of the features of this embodiment is that most of the left and right upper frames 6 are positioned below the seat 1, and the seat 1 is supported by the left and right upper frames 6. To soften the impact of the seat 1, a shock absorber (bumper member) 16 made of synthetic resin and formed with an arc-shaped cross section that is long from front to back is fixed to the top surface of the upper frame 6 with screws 17 at the front and rear.

[0043] The front end 16a of the cushioning material 16 is bent downward to cover the upper ends of the front legs 4, and the rear end 16b of the cushioning material 16 is bent inward to cover the ends of the beam material 8. Also, as shown in Figure 4(B), the cushioning material 16 is formed with a group of ribs 18, one pair on each side that come into contact with the upper frame 6, and multiple pairs on the front and back.

[0044] (2) Seat and its mounting structure As shown in Figure 3, the seat 1 comprises an outer shell 20 made of synthetic resin that is open at the top and bottom, an inner shell 21 made of synthetic resin attached to the top surface of the outer shell 20, and a cushion material 22 that is placed on top of the inner shell 21, and the cushion material 22 is covered with a skin material. The inner shell 21 has a large number of slits 23 formed in the longitudinal direction and at an angle to allow it to bend downward (expand) due to the load caused by sitting on it.

[0045] Although not shown in detail, the inner shell 21 is attached to the outer shell 20 by fitting engagement claws provided on the front, rear, left, and right sides into engagement holes in the outer shell 20. A large rectangular opening 24 is formed in the outer shell 20, so that a person can see the underside of the inner shell 21 through the opening 24 when the inner shell 21 is folded. Therefore, a person can see the slits 23 of the inner shell 21 through the opening 24 when the inner shell 21 is folded.

[0046] As clearly shown in Figure 3, the outer shell 20 is shaped like a shallow tray, with a wall that forms the outer periphery and a wall that forms the inner periphery, and inside it are formed several reinforcing ribs 25 that extend long in the left-right and front-rear directions. The seat 1 is supported by the left and right upper frames 6 in a state where both ends are supported, and the presence of the groups of reinforcing ribs 25 ensures high support strength despite the large opening 24 (the left and right outer shells 20 are hidden below the seat 1, and the small support span of the seat 1 also contributes to the high support strength).

[0047] As shown in Figures 4 and 7(A), contact members 26 that rest on the cushioning material 16 are attached to the left and right sides of the rear feet 5. The contact members 26 are made of a soft material such as rubber or elastomer, and as shown in Figure 7(A), are fitted by being pressed into mounting holes 27 provided in the outer shell 20. In addition, on the inside of the contact members 26 located at the rear front of the outer shell 20, anti-vibration projections 28 protrude downwards and are close to the cushioning material 16. This allows the user to rest their body in a seated position. left and right Even if the seat is shifted to the left or right, the seat 1 can be prevented from swinging left or right.

[0048] The inner shell 21 and the cushion material 22 are shaped to bulge downward (concave downward) so as to encase the buttocks of the seated person from below, and therefore the lower surface of the outer shell 20 also has a shape that bulges downward when viewed from the front. As can be seen from Figure 4, the beam material 8 is bent so as to bulge downward following the shape of the lower surface of the outer shell 20.

[0049] A U-shaped support bracket 29 having a horizontal support shaft 29a and left and right arm portions 29b tilted backward in side view is fixed to the beam material 8 by welding, and the outer shell 20 of the seat 1 is connected to the support shaft 29a of the support bracket 29. The support bracket 29 is made of a round bar material, and the seat 1 rotates up and down around the support shaft 29a of the support bracket 29. The arm portions 29b of the support bracket 29 are tilted backward in side view so that the support shaft 29a is located behind the beam material 8.

[0050] As can be seen from Figures 2(C) and 4(A), the seat 1 and the portion near its rear end are connected to the support shaft 29a, but since the support shaft 29a is located higher and further back than the beam material 8, the seat 1 can be raised and rotated without its rear edge hitting the outer shell 20.

[0051] To elaborate further, when connecting the left and right outer shells 20 with the beam material 8, it is preferable to position the beam material 8 as far forward as possible in order to increase the strength of the leg device 2, but by tilting the support bracket 29 backward when viewed from the side as in this embodiment, the beam material 8 is positioned as far forward as possible within the range that ensures the required nesting pitch, while the rear end of the seat 1 is connected to the support shaft 29a, allowing the seat 1 to be raised and rotated.

[0052] In this embodiment, the support shaft 29a is inserted inside the outer shell 20, so when the seat 1 is tilted forward, the underside can be brought close to the outer shell 20, improving the stability of the seat 1 when in use, and when the seat 1 is raised and rotated, the height can be lowered, improving running stability when moving.However, because the support bracket 29 is in an inclined position, it is possible for the support shaft 29a to be inserted inside the outer shell 20.

[0053] (3) Details of the connecting structure 4 and 5, the base 1 is connected to the support shaft 29a via an upper bearing cap 31 made of a metal plate and a lower bearing cap 32 made of synthetic resin. The lower bearing cap 32 has a width that allows it to fit between the left and right arm portions 29b of the support bracket 29 with a small gap, while the upper bearing cap 31 has a width that is significantly smaller than that of the lower bearing cap 32, and the upper and lower bearing caps 31 and 32 sandwich the support shaft 29a in half from above and below.

[0054] The upper bearing cap 31 has flanges 31a and 31b at the front and rear of the portion surrounding the support shaft 29a, and these flanges 31a and 31b overlap with the lower bearing cap 32. The lower bearing cap 32 bulges downward and has numerous ribs 33 formed inside. A rectangular positioning hole 34a is formed in the rear flange 31b of the upper bearing cap 31, and the lower bearing cap 32 has a positioning protrusion 34b that fits into the positioning hole 34a from below. The positioning protrusion 34b is formed by a group of ribs.

[0055] As shown in Figures 4 and 5, a recess 36 into which the bearing cap 32 fits is formed in the outer shell 20, and the recess 36 has an escape hole 37 to prevent interference between the bearing portion of the upper bearing cap 31 and the positioning protrusion 34b of the lower bearing cap 32, and the lower bearing cap 32 overlaps the step surrounding the escape hole 37 with the upper bearing cap 31 interposed therebetween.

[0056] As shown in Figure 5(A), three cylindrical portions 34c are formed side by side at the front of the lower bearing cap 32, and upward screws 38 are inserted into the cylindrical portions 34c from below and pass through the front flange 31a of the upper bearing cap 31. As can be seen from Figure 5(A), the upward screws 38 are screwed into a pair of left and right female threaded holes 38a provided in the outer shell 20. In the upper bearing cap 31, the insertion holes through which the upward screws 38 pass are denoted by the reference symbol 38b. The female threaded holes 38a are illustrated as being tapped into the bearing outer shell 20, but it is preferable to attach nuts such as push nuts or plate nuts to the outer shell 20.

[0057] There are three upward screws 38 lined up on the left and right, and the two upward screws 38 at the left and right ends are used to fasten the upper and lower bearing caps 31, 32 together with the outer shell 20, while the middle upward screw 38 is used to temporarily hold the upper and lower bearing caps 31, 32 to the support bracket 29. Therefore, the front flange 31a of the upper bearing cap 31 is formed with a tapped hole 38c (see, for example, Figure 6(A)) into which the middle upward screw 38 is screwed.

[0058] The rear part of the lower bearing cap 32 is fastened together to the outer shell 20 and the upper bearing cap 31 by two downward screws 39 on the left and right as shown in Fig. 5(C). For this reason, as shown in Figs. 5(A) and 5(B), screw insertion holes 40 are formed in the rear end part of the outer shell 20 and the rear flange 31b of the upper bearing cap 31. In addition, as shown in the right end part of Fig. 5(A), the lower bearing cap 32 has a pair of left and right female threaded holes 41 into which the downward screws 39 are screwed.

[0059] As shown in Figure 6(A), a C-shaped sleeve 42 is fitted onto the support shaft 29a of the support bracket 29 and fixed with a screw 43. The sleeve 42 is intended to allow the seat 1 to rotate smoothly, and is made of a synthetic resin with a low coefficient of friction, such as POM resin. The sleeve 42 has a length shorter than the left-right length of the support shaft 29a, and therefore the lower bearing cap 32 is formed with a first recess 46 into which the sleeve 42 fits so that it cannot shift left or right.

[0060] The first recesses 46 are formed in the group of ribs 33, and second recesses 45 that surround the support shaft 29a from below are formed on the left and right outside of the first recesses 46 by similarly cutting out the upper ends of the ribs 33 in an arc shape. In this embodiment, the lower bearing cap 32 is held against the support bracket 29 so that it cannot shift left or right, and therefore the rear part of the seat 1 is held so that it cannot shift left or right.

[0061] Furthermore, a third recess 47 is formed at the bottom of the first recess 46, into which an elastic cylinder 48 made of rubber or elastomer fits in a reclined position. The elastic cylinder 48 functions as a damper that applies resistance to the rotation of the seat 1, and also as a stopper that holds the seat 1 in an upright and rotated position. In other words, because the seat 1 rotates while the elastic cylinder 48 is compressed and deformed, an appropriate amount of resistance is applied to the rotation of the seat 1, and the seat 1 will not suddenly fall over even if you let go of it midway through its tilting rotation (midway through unfolding). Furthermore, as can be seen from Figure 6, when the seat is tilted and in use, the elastic cylinder 48 is compressed and deformed, preventing rattling or floating.

[0062] On the other hand, when the seat 1 is raised and rotated, the elastic cylinder 48 returns to its original position at the slit in the sleeve 42. Therefore, in order to tilt and rotate the seat 1, a certain amount of force must be applied to the seat 1 to compress and deform the elastic cylinder 48, so the seat 1 is maintained in the raised position. Therefore, when the seat 1 is raised and rotated, the center of gravity can be positioned directly above the support shaft 29a or in front of the support shaft (it will not tip over under its own weight).

[0063] If the seat surface of the seat 1 hits the backrest 3 when the seat 1 is raised and rotated, this could easily scratch the backrest 3 or the covering material of the seat 1. Therefore, it is preferable to keep the seat 1 in a state where it does not hit the front of the backrest 3. In this regard, in this embodiment, as shown in FIG. 6(B) (also see FIG. 5(A)), stopper portions 49 are formed on the left and right sides of the recess 36 in the outer shell 20, against which the arm portions 29b of the support bracket 29 hit when the seat 1 is raised, thereby regulating the raised and rotated position of the seat 1.

[0064] As shown in Figure 6(A) (see also Figure 3), a longitudinal relief slot 50 into which the upper end of the upper bearing cap 31 fits is formed at the rear end of the inner shell 21. In other words, by fitting the upper end of the upper bearing cap 31 into the inner shell 21, the support shaft 29a is positioned as high as possible.

[0065] (4) Summary The four-legged form of chair with a fixed seat is the most popular form and is used in a variety of places, but the chair of this embodiment has the appearance of this popular chair when the seat 1 is reclined and rotated in the unfolded state, and does not look like a foldable chair (the folding components are not exposed). Therefore, although it is a folding chair, it does not have the "foldable chair feel" and has a simple and neat appearance.

[0066] If the foldable function is obvious from the exterior, it may be too functional and difficult to use depending on the environment or atmosphere, but in this embodiment, the foldable function is not visible at all when in use, so it can be used in a variety of places without feeling out of place, thereby improving the product value.

[0067] In addition, in the unfolded state, the seat 1 is supported at both ends by the left and right upper frames 6, but because the distance between the left and right upper frames 6 is narrower than the distance between the left and right sides of the seat 1, no special components such as metal support frames are required, and even with an outer shell 20 made of synthetic resin, the necessary support strength can be ensured by simply providing reinforcing ribs 25. This is therefore advantageous in terms of cost as well.

[0068] As already mentioned, there are advantages to locating the beam 8 at the rear and to having the pivot point of the seat 1 located inside the seat 1. It is possible to place another beam behind the illustrated beam 8, but in this case, it will be necessary to take measures such as curving it downward so as not to interfere with the rotation of the seat 1.

[0069] When the outer shell 20 is formed into a square-shaped loop structure (frame structure) as in the embodiment, the underside of the inner shell 21 can be seen through the opening 24 in the folded state, but the numerous slits 23 catch the eye of the user, and thus, unlike the simple appearance in the unfolded state, the bending function of the inner shell 21 is intuitively apparent to the user. In other words, the appearance is very different between the unfolded and folded states, which is full of surprise. This novelty can improve the commercial value. As already mentioned, it can save materials.

[0070] In this embodiment, the left and right back support columns 9 are integrally connected at their upper ends, so that the robustness of the chair as a whole can be ensured even when the left and right upper frames 6 are connected by only one beam member 8. In other words, when the upper ends of the left and right back support columns 9 are integrally connected, the backrest 3 also functions as a reinforcing member, which can significantly improve the stability of the left and right back support columns 9 (particularly, it can improve resistance to torsion in plan view). This is like connecting the left and right upper frames 6 with two beam members 8, one at the front and one at the back, so that the chair as a whole can ensure high rigidity even when the left and right upper frames 6 are connected by only one beam member 8.

[0071] (5) Other embodiments In the first embodiment, the upper frame 6 was in a horizontal position with a constant height, but in the second embodiment shown in Figures 8(A) and (B), the portion of the upper frame 6 in front of the beam 8 is inclined slightly downward toward the front. This allows the left and right upper frames 6 to be nested while maintaining a parallel position. Because the upper frame 6 is inclined, a downward protrusion 51 is provided at the front of the seat 1 to rest on the inclined portion of the upper frame 6 in order to maintain the seat 1 in a predetermined position.

[0072] For nesting to occur, the left-right spacing between the front legs 4 and the rear legs 5 must be different, but in this embodiment, unlike the first embodiment, the left-right spacing between the front legs 4 is set to a dimension smaller than the left-right spacing between the rear legs 5. Nesting is also possible by forming the upper frame 6 in a stepped shape in side view by stepping down the portion of the upper frame 6 in front of the beams 8. Alternatively, the entire upper frame 6 may be tilted downward at the front.

[0073] In both of the above embodiments, the beam 8 is provided with a support bracket 29 that faces diagonally upward, but it is also possible to provide a bearing boss that projects downward from the underside of the seat 1 and connect the bearing boss to the upper frame 6 or the beam 8. In this case, the rotation fulcrum of the seat 1 will be located below the underside of the seat.

[0074] The seat 1 does not necessarily have to be a cushion type, and may be a single structure made of resin or wood. On the other hand, although the backrest 3 in the embodiment has a single structure, a cushion material may be placed on the front surface of the backrest 3.

[0075] 8(C) as a third embodiment, a plate-shaped bearing bracket (preferably an inverted L-shape in side view with the upper end facing rearward) 52 that fits into the interior of the outer shell 20 may be provided protruding from the rear of the upper frame 6, and a bearing rib provided inside the outer shell may be connected to this bearing bracket 52 with a pin 54. Therefore, a slit 53 into which the bearing bracket 52 fits is formed in the outer shell 20.

[0076] Furthermore, the present invention can be embodied in various forms other than those described above. For example, the front and rear legs and the upper frame can be made of synthetic resin. [Industrial Applicability]

[0077] The present invention can be embodied in a folding chair, and therefore has industrial applicability. [Explanation of symbols]

[0078] 1 seat 2 leg device 3 Backrest 4 front legs 5 Hind legs 6 Upper frame 7 Leg frame body 8 Beam material 9 Back strut 16 Cushioning material 20 outer shell 21 Inner shell 23 Slit 24 Aperture 29 Support bracket 29a Support shaft 31 Upper bearing cap 32 Lower bearing cap 42 Sleeve

Claims

1. The seat is connected to the leg device so that it can be raised and rotated around its rear as a fulcrum, and multiple units can be nested front to back in a folded state with the seat raised and rotated, The leg device is a chair including left and right leg frame bodies in which a front-to-back longitudinal horizontal upper frame is connected between the upper ends of the front and rear legs, and left and right longitudinal beam members that connect the upper frames of the left and right leg frame bodies only at portions near the rear ends thereof, The upper frame is integrally connected to the front legs, and the front upper frame extends rearward from the upper ends of the front legs, and is arranged so as not to protrude beyond the left and right outer sides of the seat, A backrest is attached to a back support located behind the seat. Folding chair.

2. The seat is supported by the upper frame on its left and right sides when tilted forward.

2. A folding chair according to claim 1.

3. The rear portion of the seat is rotatably connected to the beam member, and in the forward tilted state, the portion in front of the beam member is supported by the left and right upper frames in a state where both ends are supported.

3. A folding chair according to claim 1 or 2.

4. The seat is connected to a support bracket that protrudes upward from the beam. A folding chair according to claim 3.

5. The support bracket is formed of a rod material, and the upper end is horizontal, and the seat is connected to the horizontal portion. A folding chair according to claim 4.

6. The seat is connected to the leg device so that it can be raised and rotated around its rear as a fulcrum, and multiple units can be nested front to back in a folded state with the seat raised and rotated, The leg device has left and right leg frame bodies in which a longitudinally long horizontal upper frame is connected between the upper ends of the vertically long front legs and rear legs, and the seat is a chair in a forward tilted state, supported at both ends by the left and right upper frames, The upper frame is integrally continuous with the front legs, and the front upper frame extends rearward from the upper ends of the front legs, and is arranged so as not to protrude outside the left and right sides of the seat, and the upper frame is arranged so that the entirety or most of it is located below the seat, A backrest is attached to a back support located behind the seat. Folding chair.

7. The left and right hind legs extend upward to form the back support, and the upper ends of the left and right back supports are connected together. A chair according to any one of claims 1 to 6.

8. The seat has an outer shell that is rectangular in shape when viewed from above and has left and right horizontally elongated portions, an inner shell attached to the outer shell from above, and a cushioning material arranged on the upper surface of the inner shell, The outer shell is a strength member, and its front horizontally elongated portion is supported by the left and right upper frames. A folding chair according to any one of claims 2 to 7.

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