Folding chair

Abstract

To provide a foldable chair having a simple and elegant external appearance.SOLUTION: A leg device 2 has left and right leg frame bodies 7. The leg frame bodies 7 have four legs having horizontal upper frames 6 and the left and right upper frames 6 have their rear parts coupled by a beam material 8. A seat 1 comprises an outer shell 20 as a strength member. A support bracket 29 provided at the beam material 8 enters a recess 36 of the outer shell 20. A spindle 29a of the support bracket 29 is held and retained by upper and lower bearing caps 31, 32 inserted in the recess 36. Because a coupled part cannot be viewed in an expansion state, the chair has simplicity that is not common for a foldable one. A state of the lower bearing cap 32 forms the same plane with the outer shell 20, which provides an elegant external appearance even in a folded state.SELECTED DRAWING: Figure 4

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 Documents 1 and 2. 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] In Patent Document 1, the seat is supported by a metal reinforcing frame, and the left and right sides of the reinforcing frame are connected (fitted) to a rear (upper) beam material. Therefore, in this case, the beam material acts as a support shaft. In contrast, in Patent Document 2, in the same case as Patent Document 1, the seat is supported by a metal reinforcing frame, but left and right brackets that protrude diagonally rearward and upward in side view are fixed to the rear (upper) beam material, and the reinforcing frame is rotatably connected to the left and right brackets.

[0005] On the other hand, in Patent Document 3, the beam material located at the rear is used as a support shaft, but a bearing cap that surrounds the beam material from below is fixed to the underside of the seat, so that the seat can rotate around the axis of the rear beam material (to be precise, in Patent Document 3, the beam material is bent so that the left and right middle parts are shifted downward, and the seat is connected to the left and right middle parts of the beam material via a bearing cap. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-90792 [Patent Document 2] Patent No. 6436750 [Patent Document 3] Japanese Patent Publication No. 2020-62353 Summary of the Invention [Problem to be solved by the invention]

[0007] In Patent Document 1, the reinforcing frame is exposed when the seat is upright and folded, so it is hard to say that it looks good when folded, and it lacks a sense of neatness and simplicity. On the other hand, in Patent Document 2, the reinforcing frame is covered with a cover, so it can be said that it has been treated aesthetically, but the rear part of the cover is quite thick, so it is hard to say that it is simple and neat enough. Similarly, in Patent Document 3, the entire bearing cap protrudes from the underside of the seat, so it is hard to say that it is simple and neat enough when folded.

[0008] In addition, in both patent documents, the left and right leg frames that make up the leg device are entirely exposed below the seat, which means that the width of the entire chair is inevitably much larger than the width of the seat, making it difficult to make it 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.

[0009] Furthermore, in all of the patent documents, the connection between the seat and the leg device also serves as a load support, so the structure must ensure both smooth rotation and strength, which creates the problem of many design restrictions.

[0010] The present invention was made against the background of the current situation, and aims to disclose a folding chair that is excellent in design and the like. [Means for solving the problem]

[0011] The present invention includes various configurations, typical examples of which are specified in each claim. The folding chair according to the invention of claim 1 is as follows: "The seat is connected to the leg device so that it can be raised and rotated around its rear as a fulcrum, and in the folded state with the seat raised and rotated, multiple units can be nested one behind the other." In this basic configuration, "The leg device has left and right leg frames and left and right longitudinal beam members connected to the rear portions thereof. A recessed portion with an opening facing downward is formed in a portion of the seat behind the beam material, The beam material is Towards the recess A support bracket is provided that enters from below. hand , The support bracket In the recess of Enter The upper part The seat is rotatably connected to the It has the following characteristics.

[0012] The invention of claim 2 is the same as claim 1, "The seat has an outer shell as a strength member and an inner shell disposed thereon, and the left and right intermediate portions of the outer shell to the above While the recess is formed, The support bracket is U-shaped and has left and right arms and a support shaft connected between the upper ends thereof, and the arms are tilted backwards in a side view, with the lower bearing cap supporting the support shaft from below being positioned within the recess. The structure is as follows.

[0013] The invention of claim 3 is the same as claim 2, "The support shaft is held from above by an upper bearing cap, and the upper bearing cap, lower bearing cap and outer shell are fastened together with screws." The structure is as follows.

[0014] The invention of claim 4 is the same as claim 2 or 3, "When the seat is raised and rotated, the outer shell is set to contact the left and right arms of the support bracket, and the left and right arms prevent the outer shell from shifting left and right." The structure is as follows.

[0015] The invention of claim 5 is the same as claim 3 or 4, "An elastic resistor that holds the seat in an upright and rotated state is disposed on the lower bearing cap or the upper bearing cap, and the seat is rotated upright by elastically deforming the elastic resistor." The structure is as follows.

[0016] The invention of claim 6 is an independent claim that exists alongside claim 1. the law of nature, The seat is connected to the leg device so that it can be raised and rotated with its rear part as a fulcrum. the law of nature, The leg device has a longitudinal length between the upper ends of the front legs and the rear legs. of The upper frame has left and right leg frames that are connected together. The left and right leg frames are formed in a V-shape that widens forward in a plan view, so that multiple chairs can be nested front to back when the seat is raised and rotated to fold. In this basic configuration, 「 The left and right upper frames is in a horizontal position The entire seat is located inside the left and right outer ends of the seat, and the rear part is At a site in front of the hind legs Connected by long beams on the left and right In the deployed state, the seat is supported by the upper frame at a position in front of the beam material, and, The seat is rotatably connected to a support bracket provided on the beam or upper frame in a state where the pivot point does not extend forward of the axis of the beam. The structure is as follows. [Effects of the Invention]

[0017] In claim 1, the support bracket is recessed into the seat and the pivot point is located inside the seat, preventing components from being exposed from the underside of the seat when folded, contributing to a simple and clean appearance. Furthermore, because the connecting parts are hidden below the seat surface, there is no need for connecting components to protrude on both sides of the seat, which increases the design freedom of the leg frame. As a result, the leg frame is prevented from or prevented from being exposed on the left and right sides of the seat, simplifying the design when the seat is unfolded.

[0018] Furthermore, because the pivot point of the seat is located inside the seat, the seat can be prevented from swinging too far when rotated, allowing the beam to be moved as far back as possible while bringing the seat close to the backrest in the folded state. The nesting pitch of the chair is determined by the position of the beam, but because the beam can be moved as far back as possible, the nesting pitch can be made as small as possible, contributing to the effective use of storage space.

[0019] As in claim 2, when the outer shell is used as a reinforcing member of the seat, the outer shell also functions as a cover, which is particularly beneficial in terms of aesthetics. In addition, because the lower bearing cap is housed in a recess in the outer shell, it appears as if the lower bearing cap is part of the outer shell, ensuring a simple and neat appearance when folded.

[0020] In addition, because the support bracket is tilted backward in side view, the pivot point of the seat is located behind and above the beam, so the seat can be rotated to fold and unfold without any problems. Also, even if the upper frame that constitutes the leg frame is located below the seat, as in the embodiment, the seat can be rotated without its rear end hitting the upper frame.

[0021] When connecting the seat to the beam, the middle part of the beam toAlthough it is theoretically possible to bend the crank portion to form a support bracket, forming a crank portion on a beam is a tedious process, and there is also the risk that the strength of the beam will be reduced by bending.In contrast, as in claim 2, if the support bracket is made as a separate member from the beam and fixed to the beam by welding or the like, the problem of reduced strength of the beam will not occur at all. In addition, the underside of the seat is often curved so that it bulges downward when viewed from the front in order to match the profile of the user's buttocks, but in claim 2, the beam material can be formed into a curved state without any problems, which has the advantage of avoiding interference with the seat.

[0022] In this case, the support brackets are not subjected to heavy loads, so they can be made from thin materials that are easy to bend, while the upper frame and beams are made to a suitable thickness to ensure high strength, allowing each component to be selected optimally while still maintaining its functionality. In other words, it is possible to use the right material in the right place.

[0023] In the configuration of claim 3, the support shaft is surrounded from above by an upper bearing cap and from below by a lower bearing cap, improving the connection strength of the support shaft and the stability of the seat. In this case, if the configuration of claim 4 is adopted, the arm can function as a stopper to keep the seat upright and prevent the seat from swaying side to side, improving the quality of the chair without complicating the structure.

[0024] Fitting a sleeve onto the support shaft as in the embodiment is preferable because it allows the seat to rotate smoothly. Also, providing an elastic resistor as in claim 5 allows the seat to be held in the folded state without impairing the ease of rotation of the seat, preventing the seat from tipping over and rotating due to vibrations or the like while moving in the folded state.

[0025] Furthermore, since the elastic resistor functions as a damper that applies resistance to the rotation of the seat, even if a person releases their hands from the seat while reclining, the seat will not suddenly collapse, but will collapse smoothly and smoothly. This creates a sense of luxury and improves the product value. Using a sleeve to hold the seat in the folded state, as in the embodiment, is advantageous because it simplifies the structure.

[0026] In the invention of claim 6, the leg frame body constituting the leg device roughly forms a downward-facing open U-shape in side view, making it easy to hide most of the leg frame body under the seat. Therefore, the leg device is prevented from being exposed to the left and right 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, allowing for a very simple and neat design despite the folding mechanism.

[0027] To put it simply, the design has a simple and clean appearance whether it is unfolded or folded, so it can blend in anywhere with the same simple appearance as a non-folding four-legged chair with a fixed seat.

[0028] 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 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.

[0029] Furthermore, when the seat is tilted forward, the left and right sides are supported by the upper frame. can This has the advantage of improving the stability of the seat when seated. Furthermore, in claim 6, since the leg frame can support the load of the seat, by separating the connecting function from the supporting function, there is also the advantage of improving the freedom of design of the connecting part by the support bracket and ensuring smooth rotation.

[0030] In addition, in claim 6, the upper frame is positioned below the seat and the left-right distance between the upper frame is smaller than the left-right width of the seat, so the seat can be stably supported without taking special measures such as providing a metal reinforcing frame. Therefore, the necessary strength can be ensured while preventing the structure from becoming complicated. [Brief explanation of the drawings]

[0031] [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

[0032] (1) Overview Next, embodiments of the present invention will be described with reference to the drawings. First, a first embodiment shown in FIGS.

[0033] As shown in Figure 1, the chair comprises a seat 1, a leg device 2 supporting the seat, and a backrest 3. The leg device 2 comprises left and right leg frame bodies 7, each of which has a horizontal upper frame 6 that is longitudinal from front to back and connected between the upper ends of the front legs 4 and rear legs 5, and a single beam member 8 that is longitudinal from left to right and connects the upper frames 6 of the left and right leg frame bodies 7 only at positions near their rear ends. The seat 1 is connected to the beam member 8 so as to be able to rotate up and down. Therefore, the beam 8 is located in front of the rear legs 5 .

[0034] 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).

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] As shown in Figure 2(C), when the memo pad 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 pad 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 pad 12 is not installed (the left side). In this embodiment, however, the space between the memo pad 12 and the backrest 3 widens toward the side where people enter and exit, preventing the memo pad 12 from getting in the way when the user moves their body sideways, allowing them to sit down or leave the seat smoothly.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] (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 23 that is placed on top of the inner shell 21, and the cushion material 23 is covered with a skin material. The inner shell 21 has many 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.

[0044] 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.

[0045] 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).

[0046] 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, a downward-facing anti-vibration protrusion 28 is provided on the inside of the contact member 26 located at the rear front of the outer shell 20, close to the cushioning material 16. This prevents the seat 1 from swaying left and right even if the user shifts their body while seated.

[0047] 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.

[0048] 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 with a smaller diameter than the beam material 8 and the leg frame body 7, and the seat 1 rotates up and down around the support shaft 29a of the support bracket 29 as a fulcrum. The arms 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.

[0049] 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.

[0050] 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.

[0051] 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, but 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. This is a major feature of this embodiment and can be considered an independent invention.

[0052] (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 arms 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.

[0053] 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.

[0054] As shown in Figures 4 and 5, a recess 36 into which the lower 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.

[0055] 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 labeled 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.

[0056] 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 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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] Furthermore, a third recess 47 is formed at the bottom of the first recess 46, into which an elastic cylinder 48 (elastic body) made of rubber or elastomer fits in a reclined position. The elastic cylinder 48 is an example of an elastic resistor as defined in the claims, and functions as both a damper means that applies resistance to the rotation of the seat 1 and a stopper that keeps 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 will not suddenly collapse even if you let go of it midway through the 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 rattles and lifting.

[0061] 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).

[0062] 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.

[0063] 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.

[0064] (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 look like a folding chair and has a simple and neat appearance.

[0065] 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.

[0066] 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.

[0067] The lower bearing cap 32 is flush with the underside of the outer shell 20 (is flush with the lower bearing cap 32), and is like a part of the outer shell 20, so that the seat has a simple and natural appearance even in the folded state. The advantages of having the beam member 8 located at the rear and having the pivot point of the seat 1 located inside the seat 1 have already been described.

[0068] By sandwiching the support shaft 29a between the upper and lower bearing caps 31, 32 as in the embodiment, it is possible to prevent a load from being applied to a narrow portion of the outer shell 20, thereby ensuring high support strength. Furthermore, the advantages of the sleeve 42 and the elastic cylinder 48 have already been described. In this embodiment, the bearing caps 31, 32, the sleeve 42, and the elastic cylinder 48 can be unitized with a single upward screw 38, which reduces the effort required for managing parts and improves assembly accuracy.

[0069] In this embodiment, the arm portion 29b of the support bracket 29 can be used to determine the upright position of the seat 1, and the arm portion 29b can also be used to determine the left and right position of the seat 1, thereby simplifying the structure and improving the quality of the chair. Also, in this embodiment, the left and right back support columns 9 are connected together at their upper ends, so even if the left and right upper frames 6 are connected by only one beam member 8, the chair as a whole can ensure high robustness.

[0070] In the embodiment, the sleeve 42 is formed in a C-shape, but the support shaft 29a may be a separate member from the arm 29b, and the sleeve 42 may be formed as a cylinder. In this case, a hole into which the elastic cylinder 48 fits in the folded state may be provided in the sleeve 42.

[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 pivot point of the seat 1 will be located below the underside of the seat. Note that the seat 1 does not necessarily have to be a cushion type, and may be a single-piece structure made of resin or wood. On the other hand, although the backrest 3 in the embodiments has a single-piece structure, a cushion material may be placed on the front surface of the backrest 3.

[0074] 8(C), a support bracket 52 having an inverted L shape in side view is welded to the inner surface of the upper frame 6 at a position rearward of the beam material 8, and a rearward protruding portion 52a of the support bracket 29 is inserted into a slit 53 formed in the outer shell 20, and the rearward protruding portion 52a is connected to a rib (not shown) of the outer shell 20 by a pin 54. The pin 54 is preferably inserted into the rearward protruding portion 52a and the rib via a bushing.

[0075] In this embodiment as well, the pivot point of the seat 1 is located above and behind the axis of the beam 8, so the seat 1 can be rotated without its lower edge hitting the upper frame 6. Also, because the pin 54 is located inside the outer shell 20, only a portion of the support bracket 54 is exposed in the folded state, resulting in a simple appearance. A bearing cap may be located inside the outer shell as a support means for the pin 54.

[0076] It is also possible to fix the support bracket 54 to the beam material 8. It is also possible to fix the support bracket 52 to the upper frame 6 or the beam material 8, while providing a downward boss portion protruding from the outer shell 20 and connecting the boss portion and the support bracket 52 with a pin.

[0077] 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. The outer shell can be a type that does not have openings at the top or bottom. Square elastic bodies or leaf springs can also be used as elastic resistors. The connecting structure of the present invention can also be applied to chairs whose leg devices are composed of inverted Y-shaped leg frames. [Industrial Applicability]

[0078] The present invention can be embodied in a folding chair, and therefore has industrial applicability. [Explanation of symbols]

[0079] 1 seat 2 leg device 4 Front legs 5 Hind legs 6 Upper frame 7 Leg frame body 8 Beam material 20 outer shell 21 Inner shell 29,52 Support bracket 29a Support shaft 29b Arm 31 Upper bearing cap 32 Lower bearing cap 36 Recess 42 Sleeve 48 Elastic cylinder (elastic resistor)

Claims

1. A chair in which the seat is connected to a leg device so that it can be raised and rotated around its rear portion as a fulcrum, and in which a plurality of chairs 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 and left and right longitudinal beam members connected to the rear portions thereof, and a recess with an opening facing downward is formed in a portion of the seat behind the beam members, A support bracket is provided on the beam member and extends from below toward the recess of the seat, The seat is rotatably connected to an upper portion of the support bracket that is inserted into the recess of the seat. Folding chair.

2. The seat has an outer shell as a strength member and an inner shell disposed thereon, and the recess is formed in the left-right intermediate portion of the outer shell. The support bracket is U-shaped and has left and right arms and a support shaft connected between the upper ends thereof, and the arms are tilted backwards in a side view, with the arms tilting upwards and backwards, and a lower bearing cap that supports the support shaft from below is arranged to fit within the recess.

2. A folding chair according to claim 1.

3. The support shaft is held from above by an upper bearing cap, and the upper bearing cap, lower bearing cap and outer shell are fastened together with screws. A folding chair according to claim 2.

4. When the seat is raised and rotated, the outer shell is set to contact the left and right arms of the support bracket, and the left and right arms prevent the outer shell from shifting left and right. A folding chair according to claim 2 or 3.

5. An elastic resistor is disposed on the lower bearing cap or the upper bearing cap to hold the seat in an upright rotated state, and the seat is rotated upright by elastically deforming the elastic resistor. A folding chair according to claim 3 or 4.

6. The seat is connected to the leg device so that it can be raised and rotated around its rear as a fulcrum, The leg device has left and right leg frame bodies in which an upper frame in the front and rear longitudinal directions is integrally connected between the upper ends of the front legs and the rear legs, and the left and right leg frame bodies form a V-shape that widens in front in a plan view, so that multiple chairs can be nested front and back in a folded state with the seat raised and rotated, The left and right upper frames are positioned horizontally and entirely inside the left and right outer ends of the seat, and their rear portions are connected by left and right longitudinal beam members at positions forward of the rear feet, and the seat is supported by the upper frames at a position forward of the beam members in the unfolded state, The seat is rotatably connected to a support bracket provided on the beam or the upper frame in a state where the pivot point does not extend forward of the axis of the beam. Folding chair.

Images