Connection structure between connecting boss and pipe

Abstract

This chair offers excellent stability when unfolded and superior self-standing and nesting capabilities when folded. [Solution] The chair comprises a seat 1, a backrest 2, and front and rear legs 3 and 4. The front legs 3 are fixed to the front end of the side frame 5, and the rear legs 4 are rotatably connected to the rear of the side frame 5. The seat 1 is rotatably connected to the front stay 6, and the seat 1 and the rear stay 7 are connected via an interlocking member 8. When the rear end of the seat 1 is lifted, the interlocking member 8 rotates in conjunction with the rotation of the seat 1, and the rear legs 4 rotate in conjunction with this. By simply lifting the rear end of the seat 1, the front and rear legs 3 and 4 are folded into a position where they intersect in a side view. In the unfolded state, the legs 3 and 4 are positioned so that they spread downwards, providing excellent stability, and in the folded state, they intersect in an X shape, providing excellent self-supporting properties. It is.

Description

Technical Field

[0001] The present disclosure relates to Connection structure between connecting boss and pipe .

Background Art

[0002] For example, in the case of a chair that needs to be stored in a warehouse or a corner of a room when not in use, such as a chair for a conference room, in order to be able to store it in as narrow a space as possible, the chair is configured to be foldable. Also, there are some that can nest multiple legs back and forth while having self - standing ability in the folded state.

[0003] As an example, in Patent Document 1, in a chair in which a seat and a backrest are connected so as to be relatively rotatable, an X - link mechanism is formed by connecting a front leg and a rear leg at their intermediate height positions, the upper end of the front leg is connected to the side surface of the backrest, and the upper end of the rear leg is connected to the side surface of the seat, making it foldable. Further, by bending the lower end portions of the front leg and the rear leg, a configuration is disclosed that enables self - standing and nesting in the folded posture.

[0004] A folding mechanism in which the front and rear legs are connected in an X - shape, similar to Patent Document 1, is also disclosed in Patent Document 2. In this Patent Document 2, the folded posture is held by an engaging means using a pin. On the other hand, for example, as disclosed in Patent Documents 3 to 5, folding mechanisms using link members have also been proposed. In these Patent Documents 3 to 5, in the folded state, the front and rear legs do not cross in side view, and the folded posture is maintained by utilizing the self - weight.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

[0006] The purpose of this disclosure is to provide a connection structure between a connecting boss and a pipe that can fix the connecting boss to the pipe in a way that prevents it from coming loose.

[0007]

[0008] [Means for Solving the Problems]

[0009] The present invention provides a connection structure between a connecting boss and a pipe, wherein the connecting boss is provided with a first bush at its tip, and a retaining member is attached to the tip of the first bush, and the first bush and the retaining member are provided inside the pipe, and a portion of the retaining member is embedded in the inner surface of the pipe. According to the connection structure between a connecting boss and a pipe of the present invention, the connecting boss can be fixed to the pipe in a way that prevents it from coming loose.

[0010] In the connection structure between a connecting boss and a pipe of the present invention, the retaining member includes a petal-shaped retaining washer and a second bush, and the retaining washer may be sandwiched and fixed between the first bush and the second bush.

[0011] Furthermore, the surface of the first bush may be provided with a plurality of ribs.

[0012] Furthermore, the surface of the second bush may be provided with a plurality of ribs.

[0013]

[0014]

[0015]

[0016]

[0017]

[0018]

[0019]

[0020] [Brief Explanation of Drawings]

[0021] [Figure 1]A diagram showing the appearance of an embodiment, where (A) is a front perspective view in the unfolded state, (B) is a front perspective view in the folded state, (C) is a side view in the unfolded state, and (D) is a side view in the folded state. [Figure 2] A diagram showing the appearance of an embodiment, where (A) is a front view in the unfolded state, (B) is a bottom view in the unfolded state, (C) is a rear perspective view in the folded state, and (D) is a bottom perspective view in the unfolded state. [Figure 3] (A) is a partially separated bottom perspective view in the unfolded state, and (B) is a partially separated bottom perspective view. [Figure 4] (A) is a separated bottom perspective view, (B) is a bottom perspective view of the connecting part with a cap between the seat and the interlocking member, and (C) is a bottom perspective view of the connecting part without a cap between the seat and the interlocking member. [Figure 5] (A) is a central side sectional view taken along the line VA-VA of FIG. 2(B), and (B) is a side sectional view taken along the line VB-VB of FIG. 2(B) and FIG. 4(C). [Figure 6] It is a separated bottom perspective view of the upper part. [Figure 7] (A) is a separated upper perspective view of the upper part, and (B) is a sectional view taken along the line VIIB-VIIB of FIG. 1(C) and FIG. 6. [Figure 8] (A) is a rear perspective view in the folded state, (B) is a sectional view taken along the line B-B of (A), and (C) is an alternative example diagram.

Modes for Carrying Out the Invention

[0022] Next, an embodiment (specific example) of the chair disclosed in the present application will be described based on the drawings. Hereinafter, the terms "front and rear" and "left and right" are used to specify directions, and this direction is based on the orientation of a person normally sitting on the chair. The front view direction is the direction facing the seated person.

[0023] (1). Overview First, the chair's outline will be described with reference to Figures 1 and 2. The chair of this embodiment is a type often used in conference rooms and auditoriums, and as shown in Figure 1, it comprises a seat 1, a backrest 2, and rod-shaped (straight) front legs 3 and rear legs 4 that support them. The upper ends of the front legs 3 and rear legs 4 are positioned above the seat 1. The legs 3 and 4 are made of metal pipes such as steel pipes.

[0024] Seat 1, when viewed from above, is the width from left to right towards the rear. but It is formed in a roughly trapezoidal shape that narrows as it moves. On the other hand, the backrest 2 is gently curved in a forward-facing recess when viewed from above, and gently tilted backward when viewed from the side, so as to fit the user's back. The backrest 2 has a small vertical width and a sharp design.

[0025] As can be seen from Figure 1, the seat 1 is made of resin or wood and is in the shape of a board. That is, it has a single structure of one seat board. However, the seat 1 can also be made of a laminated structure in which cushioning material is stretched over the seat board (inner shell), or a type in which mesh material is stretched over a frame with openings at the top and bottom. The backrest 2 is a molded product made of synthetic resin, but it may also be made of wood. Alternatively, a structure in which cushioning material is stretched over the front can also be adopted.

[0026] The backrest 2 has side frames 5 integrally formed on both the left and right ends, extending from front to back. The side frames 5 have a width that allows them to function as armrests. Therefore, it is possible to view the armrests and the backrest 2 as being integrated. As shown in Figures 1(A) and 2, the backrest 2 is made lower in height on both the left and right sides, creating a smooth continuity with the side frames 5. This results in a clean and streamlined design.

[0027] The upper end of the front leg 3 is fixed to the front end of the side frame 5, while the rear leg 4 is connected to the side frame 5 so as to pivot back and forth using its upper end as a pivot point. Therefore, the front leg 3 and rear leg 4 can be folded from an extended state where the distance between them widens downwards when viewed from the side to a state where they intersect in an X shape when viewed from the side.

[0028] For example, as shown in Figures 2(C) and 2(D), the left and right front legs 3 are integrally fixed at the height of the underside of the seat 1 by left and right longitudinal front stays 6, and the front part of the seat 1 is rotatably connected to the front stays 6. On the other hand, the left and right rear legs 4 are also fixed at the height of the underside of the seat 1 via left and right longitudinal rear stays 7, and the rear stays 7 and the seat 1 are connected to the seat 1 via trapezoidally curved interlocking members 8 so as to be able to rotate relative to each other.

[0029] In its unfolded state, the seat 1 is supported at the front and rear by stays 6 and 7. Stays 6 and 7 are made of metal pipes such as steel pipes and are welded to the legs 3 and 4. Therefore, the chair has high support strength. When the rear end of the seat 1 is lifted, the seat 1 rotates around the front stay 6 as a pivot point, and in conjunction with this, the interlocking member 8 is pulled up and rotated so that the rear end is higher. As a result, the rear leg 4 rotates relative to the front leg 3, the seat 1, and the side frame 5, and is folded into the state shown in Figure 1(D).

[0030] For example, as shown in Figures 1(B) and 2(B), the distance between the front legs 3 is greater than the distance between the rear legs 4 in a front view and a top view. Therefore, when folded, multiple chairs can be stacked (nested) in a way that they fit together front to back. A pull rib 9 that protrudes downward is provided at the left and right middle of the rear end of the side frame 5 so that a person can easily grip it with their hands when folding the chair. In addition, a crank-shaped curved portion 7a that protrudes forward is formed on the rear stay 7 so as not to interfere with a person gripping the pull rib 9 with their hands.

[0031] (2) Connection structure between the seat and the front stay For example, as shown in Figure 3, the front part of the side frame 5 is rotatably connected to the front stay 6 by a pair of left and right front bearing parts 11 and a front cap 12 that completely covers them. The front bearing parts 11 are integrally formed on the lower surface of the seat 1 and have a semicircular downward recess 11a. On the other hand, the front cap 12 has a semicircular upward recess 12a that fits onto the front stay 6 from below, and the front cap 12 is fixed to the front bearing parts 11 with screws (not shown). Accordingly, the front cap 12 has screw insertion holes 13 and the front bearing parts 11 have tapped holes 14.

[0032] As clearly shown in Figure 3(B), the front bearing portion 11 (and front cap 12) has numerous ribs (or material-reducing recesses) to reduce friction with the front stay 6 (it is also possible to fill the material-reducing recesses with grease). Since there is a certain amount of space between the front bearing portion 11 and the left and right ends of the seat 1, auxiliary bearing portions 15 having semicircular recesses that fit onto the front stay 6 are provided projecting downward from the lower surface of both the left and right ends of the seat 1. Therefore, the front part of the seat 1 is supported by the front stay 6 at four points in the left and right directions.

[0033] As in the embodiment, providing the auxiliary bearing portion 15 allows the load to be distributed along the entire length of the front stay 6, thereby improving the support strength of the front stay 6. In this case, arranging the auxiliary bearing portion 15 closer to both ends and arranging the connection by the front cap 12 closer to the left and right middle sections has the advantage of eliminating twisting and making the rotation of the seat 1 smoother. It is also possible to connect with the front cap 12 at only one location in the left and right middle sections and provide one or two pairs of auxiliary bearing portions 15 on both the left and right sides.

[0034] It is also possible to manufacture the front bearing portion 11 and the auxiliary bearing portion 15 as separate components from the seat 1 and screw them to the seat 1, but integrally molding them with the seat 1 as in this embodiment has the advantage of preventing misalignment with the front stay 6. It is also possible to place a sleeve made of a resin material with a low coefficient of friction between the front bearing portion 11 and the front cap 12.

[0035] (3) Connection structure between the seat and the rear stay As shown in Figures 3(A) and 4(A), the interlocking member 8 comprises a long base portion 8a on the left and right sides, and long side portions 8b extending backward from both ends of the base portion 8a, giving it a generally trapezoidal shape. The left and right intermediate portions of the base portion 8a are rotatably connected to the lower surface of the seat 1 by a rear bearing portion 16 and a rear cap 17, and the rear ends of the left and right side portions 8b are rotatably connected by a pair of upper and lower clamp-type bearing bodies 18. Note that the rear cap 17 is omitted in Figures 1, 2, and 8.

[0036] The rear bearing portion 16 is integrally formed with the seat 1, and a semicircular downward recess 16a is formed in the middle portion between the front and rear. On the other hand, the rear cap 17 completely covers the rear bearing portion 16 and has a U-shaped upward recess 17a. A synthetic resin sleeve 19 is interposed between the two, and the base portion 8a of the interlocking member 8 is held by the sleeve 19. Therefore, the base portion 8a of the interlocking member 8 is connected to the rear bearing portion 16 and the rear cap 17 via the sleeve 19.

[0037] As shown in Figure 5(A), the rear cap 17 is fixed to the rear bearing portion 16 by a pair of screws 20. Therefore, screw insertion holes 21 are formed in the rear cap 17, and tapped holes 22 are formed in the rear bearing portion 16. In addition, numerous ribs (or material-reducing sections) are formed in the rear bearing portion 16 and the rear cap 17.

[0038] As shown in Figure 5(A), the sleeve 19 is C-shaped with an opening and is fitted onto the base 8a of the interlocking member 8 by expanding against elasticity. The sleeve 19 is positioned with its opening facing upward and has upward-facing stopper projections 23 on the inner surface of its left and right intermediate portions, while the base 8a of the interlocking member 8 has stopper holes 24 into which the stopper projections 23 fit. Therefore, the sleeve 19 is held in a position that prevents sliding and relative rotation with respect to the base 8a of the interlocking member 8.

[0039] As shown in Figures 4(A) and 5(B), damper grooves 25 are formed on both the left and right sides of the sleeve 19, with the depth decreasing in the direction of unfolding and rotation (the X direction in Figure 5(B)) (in other words, the thickness between the base 8a of the interlocking member 8 increases). On the other hand, cylindrical damper pins 26 that can abut and roll in the damper grooves 25 and elastic members 27 that bias the damper pins 26 into the damper grooves 25 are arranged on both the left and right sides of the rear bearing portion 16. These damper pins 26 and elastic members 27 are respectively placed in circular retaining holes 28 and 29 that open laterally, and are held in place by the rear cap 17 so that they cannot be removed.

[0040] As shown in Figures 4(A) and 5(B), damper grooves 25 are formed on both the left and right sides of the sleeve 19, with the depth decreasing in the direction of unfolding and rotation (the X direction in Figure 5(B)) (in other words, the thickness between the base 8a of the interlocking member 8 increases). On the other hand, cylindrical damper pins 26 that can abut and roll in the damper grooves 25 and elastic members 27 that bias the damper pins 26 into the damper grooves 25 are arranged on both the left and right sides of the rear bearing portion 16. The elastic members 27 are made of synthetic resin or natural rubber, but a spring such as a coil spring can also be used.

[0041] These damper pins 26 and elastic bodies 27 are positioned in laterally opening circular retaining holes 28 and 29, respectively, and are held in place by the rear cap 17 to prevent them from coming loose. When the chair is folded, the damper pins 26 are located at the deepest end of the damper groove 25, and as the seat 1 rotates toward a horizontal position, the rotational resistance of the damper pins 26 gradually increases, thereby preventing the seat 1 from tilting and rotating abruptly. In other words, the chair can be unfolded at a slow speed.

[0042] In the damper groove 25, a lock recess 30 is formed in the portion where the damper pin 26 is located in the deployed state, which stably holds the damper pin 26. This prevents continuous pressure from being applied to the elastic body 27 and also maintains the deployed state. Various mechanisms such as friction plates and hydraulic dampers can be used as damper means to provide resistance to the deployment of the chair.

[0043] As shown in Figure 4(A), the upper and lower clamp-type bearing bodies 18 have a semicircular gripping portion 18a that clamps half of the rear stay 7 and a semicylindrical arm portion 18b that fits into the side portion 8b of the interlocking member 8, with a sleeve 31 (see upper right of Figure 4(A)) interposed between the upper and lower gripping portions 18a. The sleeve 31 is rotatably held relative to the upper and lower gripping portions 18a. As can be seen from Figure 4(A), the upper gripping portion 18a has an upward-facing buffer projection 32 that bulges upward and contacts the lower surface of the seat 1. The sleeve 31 has a positioning hole (not shown) formed in the rear stay 7. Fits into A circular positioning projection (not shown) is formed. Therefore, the sleeve 31 is held in a non-rotatable position relative to the rear stay 7. The sleeve 31 is provided on the left and right clamp-type bearing bodies 18.

[0044] The upper and lower arm portions 18b are inserted into the side portion 8b of the interlocking member 8 in an overlapping state and are fixed to the side portion 8b of the interlocking member 8 by screws (not shown). Therefore, screw insertion holes 33 are made in the side portion 8b of the interlocking member 8 and the lower arm portion 18b, and a tapped hole 34 is formed in the upper arm portion 18b. The tapped hole 34 may be formed directly, or it may be formed by embedding or attaching a nut such as a hexagonal nut.

[0045] The procedure for assembling the interlocking member 8 involves first holding the rear stay 7 with the upper and lower clamp-type bearing bodies 18, then inserting the side portion 8b of the interlocking member 8 into the overlapping arm portion 18b and securing it with screws, and finally connecting the base portion 8a of the interlocking member to the rear bearing portion 16.

[0046] As previously described, the rear stay 7 has a crank-shaped curved portion 7a, but as shown in Figure 5(A), the curved portion 7a protrudes forward, and a C-shaped cushioning material 35, which the seat 1 contacts, is fitted to the tip of this curved portion 7a. The cushioning material 35 is made of synthetic resin, like the sleeves 19 and 31, and is held in place by the curved portion 7a in a non-displaceable manner by fitting a downwardly protruding positioning projection 35a into a positioning hole 36 of the curved portion 7a.

[0047] In this embodiment, when deployed, the seat 1 also contacts the gripping portion 18a of the upper clamp-type bearing body 18. Therefore, the rear of the seat 1 is supported by the rear stays 7 at three locations on the left and right sides.

[0048] (4) Supplementary information on deployable damping means (damper means) In folding chairs, the ease with which the seat can be flipped up and rotated into the folded position is inversely related to the ease with which the seat can be tilted and rotated from the folded position to the unfolded position. For example, if the seat can be folded simply by placing your hands on the rear or front end and lifting it, the seat will easily tilt and rotate into the unfolded position due to its own weight.

[0049] Therefore, the ease of folding and unfolding a chair are inextricably linked, but when the seat automatically tilts and rotates due to its own weight, a sudden tilt can produce a loud noise, which is undesirable.

[0050] In this regard, it might seem that a contact member made of an elastic material such as rubber could be provided on the support member to absorb the impact. However, this method does not reduce the impact force, so the phenomenon of the seat returning and rotating due to the recoil after tipping over is likely to occur, and it cannot be said to be a fundamental solution.

[0051] On the other hand, for example, Japanese Patent Publication No. 2001-104085 (Reference 1) discloses a means for holding the seat in a flipped-up position, in which a locking pin is provided on the seat, an engagement hole is formed in the central axis into which the locking pin fits, and the seat is held in a folded position by biasing the locking pin with a spring. In other words, in Reference 1, the locking pin is biased in the forward direction by a spring, and when the seat reaches a predetermined folded position, the locking pin moves forward by the biasing force of the spring, and the seat is held in the folded position.

[0052] Now, when a seat tilts and rotates from an upright position, the speed of tilting and rotation due to its own weight increases as the tilt angle increases. On the other hand, in Reference 1, resistance is applied to the rotation of the seat, but since the magnitude of the resistance is constant, it is difficult to tilt and rotate the seat slowly, and therefore, a technique for tilting and rotating the seat slowly is required.

[0053] The damper mechanism of this embodiment has aspects that meet the above requirements. Furthermore, the damper mechanism (damper device) of this embodiment can be generalized as a chair having the following features.

[0054] In other words, the chair comprises a seat, a backrest, and a pair of front and rear legs on the left and right sides, and is configured such that when the seat is flipped up and rotated so that its front or rear end is raised, it is in a folded position, and when the seat is tilted and rotated in the folded position so that its front or rear end is tilted, it is in an unfolded position where one can sit on the seat, and is provided with a damper means that applies resistance when the seat is tilted and rotated to reduce the speed of the tilting and rotating motion.

[0055] This feature prevents the seat from tilting and rotating suddenly (in other words, from the chair unfolding abruptly), thus preventing any impact during unfolding. This allows the unfolding process to be performed safely and quietly.

[0056] In the first deployment example of this feature, the damper means is set to gradually increase the resistance to the tilting and rotating movement of the seat. In this deployment example, acceleration is prevented from occurring in the tilting and rotating movement of the seat, allowing the entire unit to rotate slowly. Therefore, the safety and quietness of the deployment operation can be further ensured. Since the resistance during deployment and the resistance during folding are inversely related, the resistance gradually decreases during folding. Therefore, the transition to the folded position can also be ensured.

[0057] In the second deployment example, the seat is rotatably connected directly to or via interlocking members to stays located on the left and right front legs or rear legs, the stays or interlocking members being connected to the seat via bearing members, and the damper means is positioned at the connection between the bearing member and the stay or the connection between the bearing member and the interlocking member to provide frictional resistance to the relative rotation between the bearing member and the stay or the relative rotation between the bearing member and the interlocking member.

[0058] In the second development example, the damping mechanism is incorporated into the connection between the seat and the stay, or the connection between the seat and the interlocking member, which allows for a more compact design without compromising aesthetics. In particular, covering the damping mechanism with a bearing cap, as in the embodiment, allows the bearing member to double as the cover, thus simplifying the structure and proving beneficial.

[0059] In the third deployment example, in the second deployment example, the damper means includes a ring-shaped receiving member attached to the stay or interlocking member, a contact provided on the bearing member and abutting the outer circumferential surface of the receiving member, and an elastic body also provided on the bearing member and pressing the contact toward the receiving member, wherein the distance from the axis of the stay or interlocking member to the outer circumferential surface of the receiving member gradually increases in the direction of movement of the contact during deployment.

[0060] The third development example has the advantage of gradually increasing resistance with a very simple structure. In this case, the contact may be made of an elastic material or a hard material such as metal or hard synthetic resin. In either case, the contact will move while being sandwiched between the receiving member and the bearing member.

[0061] In the fourth development example, the contact is a roller shape that rotates around an axis parallel to the stay, a groove is formed on the outer circumference of the receiving member on which the contact rolls, and the distance from the axis of the stay to the groove gradually increases in the direction of movement of the slider.

[0062] In the fourth deployment example, the contact fitting does not detach because it is fitted into the groove. Furthermore, since the contact fitting is roller-shaped and rolls around the axis, it moves like a roller bearing, which can smooth the tilting and rotation of the seat.

[0063] In other development examples, various mechanisms such as friction plates and hydraulic dampers can be used as damping means. The damper groove in the embodiment is an example of a circumferential cam, but it is also possible to use an end face cam.

[0064] The folding method of a chair that can maintain this feature is not limited to the embodiment. For example, it can also be applied to a chair in which the front and rear legs are connected in an X shape when viewed from the side. In this case, it is also possible to incorporate damper means into the connection between the legs. If the chair has front and rear stays as in the embodiment, it is also possible to incorporate damper means into the connection between the seat and the front stay, or between the interlocking member and the rear stay. Furthermore, it is also possible to form grooves such as damper grooves in the bearing part or bearing cap without using a receiving member as in the embodiment.

[0065] (5) Connection structure between the legs and the side frame For example, as shown in Figure 7(B), the side frame 5 is basically a plate-like structure with a width sufficient to support a person's elbows and a flat top surface, and has downward-facing ribs 5a extending along its entire length on the inside. Therefore, the side frame 5 has roughly an inverted L-shape in cross-section. Furthermore, because the side frame 5 has downward-facing ribs 5a, it is slim yet its rigidity against loads from above is significantly improved.

[0066] At the front end of the side frame section 5, a front boss section 37 is formed, which tapers downwards as an example of a front leg mounting section. The coupling shaft 39 is forcibly fitted into this front boss section 37 to prevent it from coming loose. The upper bush 40, retaining washer 41, and lower bush 42 are fixed to the coupling shaft 39 with screws 43, and these attitude-maintaining bushes 40, 42 and retaining washer 41 are forcibly fitted to the front leg 3.

[0067] In other words, the joint unit is composed of a joint shaft 39, upper and lower position-holding bushings 40 and 42, a retaining washer 41, and a screw 43, and the side frame 5 is fixed to the front leg 3 by the joint unit. The joint shaft 39 has multiple annular grooves formed for adhesive filling. The bushings 40 and 42 have multiple elongated ribs formed to absorb dimensional errors.

[0068] The retaining washer 41 is formed in an upward-flaring petal shape and is sandwiched and fixed by the upper and lower bushings 40 and 42. The retaining washer 41 then narrows and enters the interior of the front leg 3 downward, while being held in place so that it cannot be removed upward. In other words, the retaining washer 41 bites into the inner surface of the front leg 3, preventing it from coming loose. Therefore, the front leg 3 is fixed to the front boss portion 37 in a way that it cannot come loose. A small diameter portion 37a into which the front leg 3 fits is formed at the lower end of the front boss portion 37. The front leg 3 may also be fixed to the front end of the side frame portion 5 by other means (for example, a downward-facing shaft portion provided at the front end of the side frame portion 5 can be fitted to the front leg 3).

[0069] Similar to the front leg 3, a joint unit consisting of bushings 40 and 42 for maintaining the upper and lower posture, a retaining washer 41, and a screw 43 is fitted onto the rear leg 4 from above. A joint (lever portion) 44 is integrally formed on the upper bushing 40, and the joint 44 is connected to a rear boss portion 45 formed on the side frame portion 5 by a pivot pin 46. The rear boss portion 45 is an example of a rear leg mounting portion.

[0070] The rear boss portion 45 is integrally connected to the downward-facing rib 5a, and a groove 47 is cut open to form into which the joint 44 is fitted from below. The joint 44 is connected to the rear boss portion 45 by a pivot pin 46 having longitudinal axes on the left and right sides. Therefore, the rear leg 4 rotates back and forth with the pivot pin 46 as the pivot point. As shown in Figure 7(B), the pivot pin 46 is held in place by a screw 46a so that it cannot be removed.

[0071] In this embodiment, as previously described, the side frame portion 5 is formed in an inverted L shape with downward-facing ribs 5a, but the rear boss portion 45 does not protrude outwards, and the connecting portion of the rear leg 4 is hidden in the space below the side frame portion 5. Therefore, it has a superior aesthetic appearance. In addition, although a person may grasp the side frame portion 5 with their hands when sitting down or getting up, even in this case, the rear boss portion 45 or the pivot pin 46 will not come into contact with the palm of the hand, so the person will not feel any discomfort.

[0072] The joint 44 has a shape that is close to an inverted L when viewed from the side, with its upper end protruding forward, and a connecting hole 48 is provided at its front. When deployed, the portion of the upper surface 44a of the joint 44 behind the connecting hole 48 is set to contact the inner bottom surface of the rear boss portion 45. Therefore, even if a large downward load is applied to the side frame portion 5, the load does not act on the pivot pin 46, but rather on the upper surface 44a of the joint 44. In other words, the downward load applied to the side frame portion 5 acts on the rear leg 4 as an axial compressive force. As a result, it has high support strength.

[0073] When a user sits down in or stands up from a chair, they may grip the side frame 5 and put their weight on it. In this case, a significant portion of the user's weight acts as a downward load on the side frame 5. However, in this case, the load acts as an axial compressive force on the front and rear legs 3 and 4, so the load can be firmly supported.

[0074] (6) Supplementary information regarding the connection structure between the legs and the side frame Now, in the microfilm of Japanese Utility Model Publication No. 57-104946 (Reference 2), a reclining chair equipped with armrests and in which the seat and backrest are flexibly connected is disclosed, in which a) the front legs are integrally attached to the front end of the armrest, b) the rear legs are rotatably connected to brackets projecting downward from the middle of the front and rear of the armrest, c) the rear end of the armrest and the backrest are connected by two flexibly connected link members, d) the front legs and the seat are connected by a single link member, e) the front end of the seat is supported by a roller provided on the front legs, and f) the seat and the front legs are connected by a stepless angle adjustment device. In this Reference 2, when the backrest 2 is tilted forward, the seat rotates so that its rear end is facing upward, and the front and rear legs cross in an X shape in a side view and fold down.

[0075] While adding armrests, as shown in Reference 2, improves comfort and makes the chair more user-friendly, the problem with Reference 2 is that the seat and backrest are connected, which limits the folding position and thus restricts design flexibility. Furthermore, the need for a stepless angle adjustment mechanism to maintain posture complicates the structure.

[0076] The chair of this embodiment is characterized by the shape of the side frame 5 and the connection structure between the side frame 5 and the front and rear legs 3 and 4, and these characteristics represent an improvement on the above-mentioned problems.

[0077] These features can be summarized as follows: First, the chair comprises a seat and backrest that are separate from each other, a pair of front legs and a pair of rear legs on the left and right sides, and longitudinal side frames positioned on the left and right sides of the seat in a plan view. The seat, front legs, and rear legs are interconnected so that when the seat is flipped up and rotated so that its front or rear end is raised, the front legs and rear legs rotate in a way that brings them closer together, resulting in a folded position.

[0078] Furthermore, in addition to the above configuration, the chair with these features has a side frame that comprises a main body and a leg mounting portion provided as an integral or separate component of the main body, and one or both of the front legs and the rear legs are directly or indirectly connected to the leg mounting portion so as to be rotatable relative to each other, so as to be able to change the angle between the front legs and the rear legs in a side view.

[0079] In this feature, the side frame may be integrally connected to the backrest or it may be separate from the backrest. If the side frame and backrest are separate, the backrest is attached to either the front or rear leg. Furthermore, the side frame may or may not function as an armrest. If it functions as an armrest, it is possible to attach padding material.

[0080] This feature allows the side frame to function as an armrest, thereby improving its usability. Furthermore, regardless of whether it functions as an armrest, a person can grasp the side frame with their hands and lean their weight on it to assume a semi-crouching position when sitting down or getting up. In other words, the side frame 5 can be used as a handhold for sitting down and getting up.

[0081] Furthermore, because the backrest and seat are separate, there are fewer constraints on the folding position, allowing for greater design flexibility. The stepless angle adjustment device used in Reference 2 is unnecessary, thus simplifying the structure. Since the front and rear legs are separate components from the side frame, the side frame and legs can be manufactured from different materials, thus offering greater flexibility in terms of design and strength.

[0082] Furthermore, as in this embodiment, a configuration is adopted in which downward-facing ribs 5a are formed on the side frame portion 5 along the front and rear longitudinal directions, and the front leg mounting portion and rear leg mounting portion are covered from the side by the downward-facing ribs. and The side frame section 5 is reinforced by downward-facing ribs 5a, allowing for a slimmer design while maintaining high strength. Therefore, people can grasp it with their hands and apply their weight when sitting down or getting up without any problems. Furthermore, the leg attachment sections 37 and 45 are covered from the side by the downward-facing ribs 5a, which suppresses the exposure of the leg attachment sections 37 and 45 and improves the aesthetics. In addition, since the downward-facing ribs 5a act as a cover for the leg attachment sections (37 and 45), it is also possible to prevent fingers from getting caught between the rear legs 4 and the side frame section 5 when folding the chair.

[0083] Furthermore, integrally forming the downward-facing rib 5a with the side frame portion 5 simplifies the structure and contributes to cost reduction. It also improves the appearance. Moreover, forming the downward-facing rib 5a on the inner edge of the side frame portion 5 and integrally connecting the rib 5a with the backrest 2 results in a continuous, seamless appearance between the backrest 2 and the downward-facing rib 5a.

[0084] (7) Means for holding the folded state The chair in this embodiment is designed to allow for easy unfolding while maintaining its folded state. Specifically, as shown in Figure 3, for example, a magnet 49 facing downward and backward is screwed to the front part of the rear leg 4 of the front stay 6 as a means for holding the chair in the folded state. As shown in Figure 8, in the folded state, the magnet 49 is in contact with the rear leg 4 and magnetically attached, holding the chair in the folded state. When a certain amount of force is applied, the magnet 49 and the rear leg 4 separate, so the ease of unfolding is not impaired.

[0085] Figure 8(C) shows an example of a means for holding the folded state, in which a catch member 50 is provided that holds the rear stay 7 from both the left and right sides. The catch member 50 is fixed to the front stay 6 with screws 51. The catch member 50 may be made of a metal plate such as a leaf spring, or it may be made of synthetic resin.

[0086] The means for maintaining the folded state is not limited to magnets 49 and catch members 50 as in the embodiment; for example, hook-and-loop fasteners or vacuum suction devices can also be used. The mounting location can also be set arbitrarily. For example, it is possible to provide it on the outer surface of the front leg 3 or the inner surface of the rear leg 4 to maintain the crossed position of the front leg 3 and the rear leg 4.

[0087] Now, while folding chairs are typically lifted and moved in their folded state, the legs and seat can sway and rotate, making them difficult to carry. Therefore, it is preferable to have a mechanism to maintain the folded state. Furthermore, it is desirable that the chair remains folded even when stored on the floor.

[0088] In this regard, Japanese Patent Publication No. 6276974 (Reference 3) discloses a folding chair in which the front and rear legs are connected in an X-shape, similar to Patent Document 1, in which the folded state is maintained using a spring-biased ball or pin. Specifically, in Reference 3, one leg is provided with a spring-biased projection (ball or pin) that protrudes toward the other leg from a direction intersecting the folding direction, and the other leg is provided with a recess (elongated hole) into which the ball or pin fits when the chair is folded. When the chair is unfolded from the folded state, the projection retracts against the spring.

[0089] Therefore, in Reference 3, when the chair is folded, a ball or pin on one leg engages with a recess on the other leg in conjunction with the folding motion, maintaining the folded state. When a certain amount of force is applied to unfold the chair from the folded state, the ball or pin disengages from the recess, and the chair unfolds. Consequently, there is no need for manual unlocking each time.

[0090] Reference 3 states that the chair can be kept in the folded state without compromising the ease of folding and unfolding, but since the protrusions, such as balls or pins, move in a direction perpendicular to the folding direction, there are concerns that the chair may not be able to be kept in the folded state if the protrusions do not move forward, or that the chair may not be able to be unfolded if the protrusions do not retract from the recesses.

[0091] The chair of this embodiment is characterized in terms of its means for holding it in a folded state, and this feature represents an improvement on the problems described above.

[0092] Furthermore, this feature can be summarized as a chair with the following configuration: The chair comprises a seat and a backrest, and a pair of front legs and rear legs on the left and right sides, and from an unfolded position in which the seat can be seated, the front and rear legs are folded by flipping up and rotating the seat so that its front or rear end is raised, and in the folded position the chair can stand on its own on the floor, and in the folded position one or both of the two members that are facing each other in the front-to-back direction and are close or in contact with each other, are equipped with catch members that hold the two members in contact or close to each other in the folded position, and these catch members are positioned so as to face the direction in which the two members are approaching each other.

[0093] In this feature, the catch member may be a separate member from the two relative moving members, or it may be integrally formed on one or both of the two members. It is also possible to provide a catch member on one member and use the catch member to capture the other member, or to provide catch members on both members and connect the catch members together.

[0094] In this feature, the catch member is oriented so that the two members move towards each other. Therefore, when the chair moves into the folded position, the catch member can function without hindering the folding of the chair, thus maintaining the folded position. Conversely, when moving from the folded position to the unfolded position, the catch member can be reliably separated. Thus, the chair can be held in the folded position without hindering the folding and unfolding functions.

[0095] As one example of how this feature can be applied, one of the two components can be made of a magnetic material, and a magnet that magnetically attaches to the other component can be attached to the other component as the catch component. In this configuration, because a magnet is used as the catch component, the folded position can be held with a very simple structure. Furthermore, when a magnet is used as the catch component, the folded position is automatically held in place by the magnetic pulling action at the end of the folded state, resulting in excellent workability.

[0096] Furthermore, when unfolding from the folded position, applying a certain amount of force to the chair in the unfolding direction will cause the magnet to detach from the other component, thus ensuring a smooth transition to the unfolded position. In addition, since the magnet's function is achieved by utilizing the fact that at least the other component is a magnetic material, and the other component is used as a means of holding the folded position, it offers further advantages in terms of structural simplification.

[0097] When using magnets as catch components, it is possible to attach magnets to both components, or to attach a magnet to one component and a magnetic material to the other. In this case, the other component may be made of a non-magnetic material (for example, aluminum or synthetic resin).

[0098] (8) Summary As already explained, when the rear end of seat 1 is lifted in the deployed state, seat 1 is pivoted upward so that its rear end is higher, using the front stay 6 as a pivot point, and in conjunction with this, the base 8a of the interlocking member 8 is pulled upward. Then, the rear leg 4 rotates using its upper end as a pivot point.

[0099] Then, when the seat 1 is fully rotated by lifting the entire chair so that it is suspended above the floor, or by lifting it so that only the lower ends of the front legs 3 are touching the floor, the center of gravity will be directly below the pull handle rib 9. As a result, the front legs 3 will change to a forward-leaning position and the rear legs 4 will change to a backward-leaning position. Consequently, the front legs 3 and rear legs 4 will be in an X-shaped position when viewed from the side. Therefore, the folded chair can stand on its own. In addition, the chair's own weight acts to widen the gap between the lower ends of the front legs 3 and the lower ends of the rear legs 4, thus maintaining the folded state.

[0100] Since the front end of the seat 1 is connected to the front stay 6, the seat 1 can be rotated by placing your hand on the pull handle rib 9 at its rear end and lifting it up. However, because the span from the pull handle rib 9 to the front stay 6 is large, the seat 1 can be reliably flipped up and rotated.

[0101] Then, simultaneously with the flip-up rotation of the seat 1, the interlocking member 8 begins to rotate with its rear end as the pivot point, and the rear legs 4 also begin to rotate accordingly. However, since the base 8a of the interlocking member 8 is connected to the middle of the front and rear of the seat 1, the interlocking member 8 rotates smoothly due to the lever action. Consequently, the rotation of the interlocking member 8 and the rotation of the rear legs 4 are smooth, and when the entire chair is lifted, or when the rear legs 4 are lifted with the lower ends of the front legs 3 touching the floor, the shift in the center of gravity causes the front legs 3 to tilt forward and the rear legs 4 to tilt backward, automatically transitioning to the folded state.

[0102] When the chair is lifted by placing a hand on the rear end of the seat 1, the entire weight of the chair rests on the seat 1, resulting in a large moment acting on the connection between the interlocking member 8 and the seat 1. Consequently, the damper pin 26 reliably disengages from the lock recess 30 against the elasticity of the elastic body 27. As folding progresses, the moment on the connection between the interlocking member 8 and the seat 1 decreases, but the frictional resistance between the damper pin 26 and the damper groove 25 decreases in proportion to the progress of folding, so the chair reliably transitions to the folded position simply by lifting it.

[0103] When the unit is folded, the magnet 49 on the front stay 6 magnetically attaches to the rear leg 4, maintaining the folded state. Therefore, when moving the unit to a warehouse or other location while lifted, the front and rear legs 3 and 4 do not swing around, allowing for stable transport.

[0104] Furthermore, when unfolding from the folded position, the rotational moment of the seat 1 increases in proportion to the rotation angle. Without any measures, the rotational speed of the seat 1 increases in proportion to the rotation angle, making it prone to sudden stopping and generating impact. However, in this embodiment, the friction between the damper pin 26 and the damper groove 25 increases gradually, so the seat 1 tilts and rotates slowly without any impact. Therefore, the unfolding operation can be performed safely and quietly.

[0105] As previously mentioned, the chairs can be nested because they stand on their own when folded. As can be seen from Figure 8, in the nested state, the front surface (seat) of the seat 1 of the chair located behind comes into contact with the clamp-type bearing 18 of the chair located in front. Therefore, damage to the seat 1 can be prevented. More precisely, the seat 1 of the chair behind comes into contact with the clamp-type bearing 18, which is positioned higher in the unfolded state, thereby restricting the front-to-back position of the chairs. Thus, one clamp-type bearing 18 serves as both a cushioning material for the seat 1 in the unfolded state and a cushioning material in the nested state. This is one of the advantages of this embodiment.

[0106] To unfold the chair, for example, one can lift the chair by placing one hand on the backrest 2 and then push down on the rear end of the seat 1. In this case, as previously described, resistance is applied to the rotation of the interlocking member 8 and the seat 1 by the damper mechanism, preventing the seat 1 from rotating suddenly and allowing for a gradual transition to the unfolded state.

[0107] The embodiments of the concept described herein have been explained above, but this concept can be implemented in various other ways. For example, it is possible to connect the seat 1 to the rear stay 7 and the interlocking member 8 to the front stay 6, and to flip up the seat 1 so that its upper end is facing upwards. Furthermore, as a means of rotating the interlocking member 8, for example, the base of the interlocking member 8 can be connected to the lower surface of the seat 1 so as to be slidable back and forth. [Note] While configurations that directly connect the front and rear legs, as shown in Patent Documents 1 and 2, have the advantage of simplifying the structure, the downward load from sitting strongly acts on the connection point between the front and rear legs, causing bending forces to be applied to the legs. This can easily reduce the durability of the legs (connection point) and also results in an unattractive appearance. On the other hand, folding mechanisms using link members, such as those described in Patent Documents 3-5, are advantageous in terms of leg strength because the load from sitting does not act as a bending force on the legs, but they have the problem of being prone to structural complexity. Against this backdrop, improvements are desired regarding folding chairs, particularly in terms of their folding mechanism and design. [Note 1] The seat and backrest are separated from each other, One pair each of front legs and hind legs, Equipped with, The configuration is such that, from an unfolded position in which a person can sit on the seat, the seat is flipped up and rotated so that its front or rear end is raised, causing the front and rear legs to move into a folded position, and in the folded position the seat is able to stand upright on the floor, The front leg and the rear leg are connected directly or indirectly so as to be able to rotate relative to each other in accordance with the switching between the deployed position and the folded position. The seat is connected to one of the front and rear legs in such a way that it can be flipped up and rotated, and to the other leg via an interlocking member that causes the front and rear legs to rotate relative to each other in conjunction with the flipping up and rotation. Folding chair. [Note 2] The aforementioned left and right front legs are connected integrally by long front stays on both sides. The aforementioned left and right rear legs are connected as a single unit by long rear stays on both sides. The seat is rotatably connected to one of the front and rear stays, and the seat and the other stay are connected by the interlocking member in such a way that the distance between the seat and the other stay can change in width. The folding chair described in Appendix 1. [Note 3] The interlocking member is positioned on the lower surface of the seat. A folding chair as described in Appendix 1 or 2. [Note 4] The aforementioned interlocking member has a continuous form with left and right longitudinal base portions and front and rear longitudinal side portions. The base is connected to the seat, and the tip of the side portion is connected to the other stay. A folding chair as described in Appendix 2 or 3. [Note 5] The interlocking member is rotatably connected to the seat and the other leg via a bearing, pin, or other pivot member, respectively. A folding chair as described in one of the appendices 1-4. [Note 6] By making the distance between the left and right front legs and the distance between the left and right rear legs different, other folding chairs can be nested front to back in the folded position. A folding chair as described in one of the appendices 1-5. [Note 7] In the deployed position, the front and rear legs are in a V-shape when viewed from the side. Of the aforementioned front and rear legs, the upper end of one leg is positioned above the seat and fixed to the side frame to which the backrest is attached, while the upper end of the other leg is rotatably connected to the side frame. In the aforementioned folded position, the front and rear legs intersect in an X-shape when viewed from the side. A folding chair as described in any of the appendices 1-6. The chair according to the first viewpoint comprises a seat and backrest that are separate from each other, and a pair of front legs and rear legs on the left and right sides. From an unfolded position in which the seat can be sat on, the front and rear legs are folded by flipping up and rotating the seat so that its front or rear end is raised. In the folded position, the chair is able to stand on its own on the floor. Furthermore, the front leg and the rear leg are directly or indirectly connected so as to be able to rotate relative to each other in accordance with the switching between the deployed position and the folded position. The seat is connected to one of the front leg and the rear leg so as to be able to flip up and rotate. The seat is connected to the other leg via an interlocking member so as to cause the front leg and the rear leg to rotate relative to each other in conjunction with the flip-up rotation. This configuration allows the seat to form part of the mechanism for folding the chair. For example, by placing a hand on the rear or front end of the seat and lifting it, it can be folded using its own weight. Therefore, it contributes to making the folding process easier. Furthermore, by indirectly connecting the front and rear legs, a form similar to a four-legged pipe chair can be easily adopted, making it easy to realize a form with excellent support stability and design. Now, while Patent Documents 3 and 4 require two types of link rods, Patent Document 5 requires a seat that is connected to the front and rear legs and also requires a link rod, resulting in a complex structure. In contrast, in the chair according to the first aspect of the present application, the seat can be used as an element of the mechanism for folding the chair, so only one interlocking member (one type) is needed, thus simplifying the structure. Furthermore, because the structure is simple, folding and unfolding can be done smoothly without twisting. In the chair relating to the second viewpoint, the left and right front legs are integrally connected by left and right longitudinal front stays. The left and right rear legs are integrally connected by left and right longitudinal rear stays. The seat is rotatably connected to one of the front stays or the rear stays. The seat and the other stay are connected by the interlocking member in such a way that the distance between the seat and the other stay can change in width. While various configurations can be used for the connection structure between the seat and the legs, using front and rear stays, as in the chair described in the second perspective, improves support stability and further simplifies the structure because the stays can be used as both reinforcing and connecting members. In the third aspect of the chair, the interlocking member is positioned on the underside of the seat, as is the case with the first or second aspect of the chair. This allows the interlocking member to be positioned in a way that is not visible while still being of the required size, thereby improving aesthetics while ensuring smooth folding and unfolding. In the chair relating to the fourth viewpoint, in the chair relating to the second or third viewpoint, the interlocking member has a continuous form with left and right longitudinal bases and front and rear longitudinal side portions, the bases being connected to the seat and the tips of the side portions being connected to the other stay. As a result, the interlocking member can be easily manufactured by bending pipe material or rod material, thus reducing costs. The interlocking member can be selected in various forms, for example, a U-shape or trapezoidal shape can be adopted. In the chair relating to the fifth viewpoint, in any of the chair relating to the first viewpoint to the fourth viewpoint, the interlocking member is rotatably connected to the seat and the other leg via a bearing, pin, or other pivot member, respectively. This results in a simple structure and smooth movement, which is advantageous in terms of cost reduction and improved ease of folding and unfolding. As a means of connecting the interlocking member to the seat and the leg so that they can move relative to each other, a sliding mechanism can also be used, for example. The chair relating to the sixth viewpoint is designed so that, in the folded position, other folding chairs can be nested front to back, by making the distance between the left and right front legs and the distance between the left and right rear legs different, as is the case with any of the chairs relating to the first viewpoint to the fifth viewpoint. This allows for efficient use of space when storing the chair in the folded position. In the chair relating to the seventh viewpoint, in any of the chair relating to the first viewpoint to the sixth viewpoint, the front legs and rear legs, in the unfolded position, form a V-shape when viewed from the side. The upper end of one of the front legs and rear legs is fixed to a side frame positioned above the seat to which the backrest is attached. The upper end of the other leg is rotatably connected to the side frame. In the folded position, the front legs and rear legs intersect in an X-shape when viewed from the side. For example, as shown in Patent Documents 1 and 2, when the front and rear legs are connected in an X-shape, there are problems in terms of strength and aesthetics. However, the chair according to the seventh aspect has the same appearance as a four-legged pipe chair when in use, thus being superior in strength and aesthetics. Furthermore, when folded, the front and rear legs intersect in an X-shape, resulting in excellent self-support in the folded position. In addition, since each leg does not need to be bent in a complex manner, it is also advantageous in terms of cost. [Industrial applicability]

[0108] The concept described herein can be embodied in a folding chair. Therefore, it can be used industrially. [Explanation of symbols]

[0109] 1 seat 2 Backrest 3 front legs 4. Hind legs 5. Side frame section 5a Downward rib 6 Front Stay 7 Rear Stay 8 Interlocking Member 8a Base of the interlocking member 8b Side portion of the interlocking member 9 Pull tab rib 11 Front bearing section 12 Front cap 16 Rear bearing section 17 Rear cap 18. Clamp-type bearing 26 Damper pins 27 Elastic members 37 Front boss section 44 joints 45 Rear boss section 49 Magnet as an example of a means for maintaining a folded state

Claims

1. The seat and backrest are separated from each other, One pair each of front legs and hind legs, Equipped with, From an unfolded position in which a person can sit on the seat, the seat is flipped up and rotated so that its front or rear end is raised, causing the front and rear legs to move into a folded position, in which the seat is able to stand upright on the floor. The front leg and the rear leg are connected directly or indirectly so as to be able to rotate relative to each other in accordance with the switching between the deployed position and the folded position. The seat is connected to one of the front and rear legs in such a way that it can be flipped up and rotated, and to the other leg via an interlocking member so as to cause the front and rear legs to rotate relative to each other in conjunction with the flipping up and rotation. Folding chair.

2. The left and right front legs are connected integrally by long front stays, and the left and right rear legs are connected integrally by long rear stays. The seat is rotatably connected to one of the front and rear stays, and the seat and the other stay are connected by the interlocking member in such a way that the distance between the seat and the other stay can change in width. A folding chair as described in claim 1.

3. The interlocking member is positioned on the lower surface of the seat. A folding chair as described in claim 1 or 2.

4. The interlocking member has a continuous form with left and right longitudinal base portions and front and rear longitudinal side portions, the base portions being connected to the seat, and the tips of the side portions being connected to the other stay. A folding chair as described in claim 2 or 3.

5. The interlocking member is rotatably connected to the seat and the other leg via a bearing, pin, or other pivot member, respectively. A folding chair as described in any one of claims 1 to 4.

6. By making the distance between the left and right front legs and the distance between the left and right rear legs different, other folding chairs can be nested front to back in the folded position. A folding chair as described in any one of claims 1 to 5.

7. In the unfolded position, the front and rear legs form a V-shape when viewed from the side, with the upper end of one leg positioned above the seat and fixed to the side frame to which the backrest is attached, and the upper end of the other leg rotatably connected to the side frame, and in the folded position, the front and rear legs intersect in an X-shape when viewed from the side. A folding chair as described in any one of claims 1 to 6.

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