Chair and method for manufacturing the same

Abstract

To provide a chair that allows for easy and stable seating. [Solution] The chair 1 includes a disc-shaped seat plate 3 having a first surface 3a which is the seat surface, an annular first member 5 fixed to the second surface 3b of the seat plate 3 opposite to the first surface 3a, three leg members 6a, 6b, and 6c which are fixed to the first member 5 at intervals in the circumferential direction, with one end of each fixed by a wood screw 11, and which extend in a direction in which the distance between them widens as they move away from the second surface 3b perpendicularly, and an annular second member 7 which is larger in diameter than the first member 5 and is fixed by a wood screw 12 in the middle part between one end of the three leg members 6a, 6b, and 6c and the other end opposite to that end. Each of the three leg members 6a, 6b, and 6c has a first notch 9 which partially fits into the outer circumference of the first member 5, and a second notch 10 which partially fits into the outer circumference of the second member 7. The seat board 3, the first member 9, the three leg members 6a, 6b, and 6c, and the second member 7 are made of wood.

Description

Technical Field

[0001] The present invention relates to a chair and a method for manufacturing the same.

Background Art

[0002] A chair of the prior art is described as a stool in, for example, Patent Document 1. The stool of Patent Document 1 includes a main board and a plurality of legs that extend obliquely downward and sideward from the second surface of the main board. A plurality of cutouts are formed on the outer edge of the main board to engage with the legs of other stools when a plurality of stools are stacked. Each leg is provided with a stopper that abuts on the main board of another stool when a plurality of stools are stacked. The cutout of the main board is formed in a long groove shape with a substantially constant groove width so as to engage with the legs of a plurality of other stools stacked above the main board.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above Patent Document 1, since a plurality of cutouts are provided on the main board, the sitting comfort when sitting is poor, which is not preferable for long-term sitting. When the stool of Patent Document 1 is used outdoors, for example, the ground on which the stool is installed often has undulations with earth and sand. There is a problem that the stability of the stool on such an installation surface with undulations is poor. In addition, it is preferable that a user can easily and stably sit on the seat surface of the chair from any direction.

[0005] In addition, the stool of the above Patent Document 1 has a problem that it has a large number of parts, requires time and effort for manufacturing, and has poor productivity.

[0006] The object of the present invention is to provide a chair that is easy to manufacture, allows for easy and stable seating, and a method for manufacturing the same. [Means for solving the problem]

[0007] The chair according to the present invention comprises a disc-shaped seat plate having a first surface which is the seat surface, A first annular member fixed to the second surface of the seat plate opposite to the first surface, The first member is fixed to one end of each of the three leg members by a first fastener at intervals in the circumferential direction, and the distance between them increases as they move away from the second surface in a direction perpendicular to it. The three leg members are fixed by a second fastener to the intermediate portion between one end and the other end opposite to the first end, and include an annular second member having a larger diameter than the first member, Each of the three leg members has a first notch that partially fits into the outer circumference of the first member, and a second notch that partially fits into the outer circumference of the second member. The seat plate, the first member, the three leg members, and the second member are characterized by being made of wood.

[0008] Furthermore, the chair according to the present invention is characterized in that the first member and the second member are made of a multilayer board formed by laminating multiple plywoods.

[0009] Furthermore, the method for manufacturing a chair according to the present invention is a method for manufacturing a wooden chair, The first step is to prepare a disc-shaped seat plate having a first surface which is a seating surface and a second surface opposite to the first surface, the second surface having an annular groove and a first recess, a second recess, and a third recess formed at intervals from each other around the central axis of the groove, The second step involves preparing the first ring-shaped member, A third step involves preparing a second annular member having a larger diameter than the first member, A fourth step is to prepare three leg members, each having a first notch into which the outer periphery of the first member can be partially fitted, and a second notch into which the outer periphery of the second member can be partially fitted. A fifth step involves applying adhesive to the groove of the seat plate, and fitting one annular end face of the first member into the groove to which the adhesive has been applied and bonding it, A sixth step involves fitting the outer periphery of the first member into the first notches of the three leg members, inclining the three leg members in a direction that widens the distance between them as they move away from the second surface, and fixing the first member to the three leg members with the first fastener. The present invention is characterized by including a seventh step of partially fitting the outer periphery of the second member into the second notch of the three leg members and fixing the second member to the three leg members with a second fastener. [Effects of the Invention]

[0010] In the chair according to the present invention, the first member is fixed to the three leg members by a first fastener, and the second member is fixed to the three leg members by a second fastener. Therefore, even when the chair is placed on soft, uneven ground such as soil during a visit to a grave, the three leg members are supported by the ground, allowing for stable placement. Furthermore, since the seat is disc-shaped, the user can easily and stably sit on the first surface (seat) from any direction by moving their body the shortest distance to the first surface. Moreover, since the first and second members are fixed to the three leg members by the first and second fasteners, respectively, the load when sitting can be distributed from the seat to the three leg members by the first and second members. This makes it possible to provide a chair with high resistance to loads such as impact forces from falls.

[0011] Furthermore, since the first and second members are made of multilayer boards formed by laminating multiple plywoods, high-strength first and second members can be obtained, allowing them to withstand large loads from the three leg members. This provides high resistance to impact forces on the leg members, such as from the chair falling, preventing deformation or damage to the chair.

[0012] According to the manufacturing method of the chair according to the present invention, a disc-shaped seat plate is prepared in the first step, a first member is prepared in the second step, a second member is prepared in the third step, and three leg members are prepared in the fourth step. In the fifth step, an adhesive is applied to the concave groove of the seat plate, and one annular end surface portion of the first member is fitted into the concave groove to which the adhesive is applied and adhered. Thereby, the first member can be adhered to the seat plate in a state of being positioned in the concave groove. In the sixth step, the outer peripheral portion of the first member is fitted into the first notch portions of the three leg members, and the first member is fixed to the three leg members by the first fixing tool. In the seventh step, the outer peripheral portions of the three leg members are fitted into the second notch portions of the outer peripheral portion of the second member, and the second member is fixed to the three leg members by the second fixing tool, and the chair is manufactured. Thus, since the first member is fixed to the three leg members by the first fixing tool and the second member is fixed to the three leg members by the second fixing tool, a chair having high resistance to large loads such as impact force can be easily manufactured.

Brief Description of the Drawings

[0013] [Figure 1] It is a front view showing the chair 1 of one embodiment of the present invention. [Figure 2] It is a rear view of the chair 1. [Figure 3] It is a right side view of the chair 1. [Figure 4] It is a perspective view of the chair 1 seen obliquely from above. [Figure 5] It is a perspective view of the chair 1 seen obliquely from below. [Figure 6] It is a plan view of the chair 1. [Figure 7] It is a cross-sectional view seen from the cutting plane line VII-VII of FIG. 6. [Figure 8] It is a bottom view of the chair 1. [Figure 9] It is a side view of the leg member 6a. [Figure 10] It is a rear view of the leg member 6a seen from the left side of FIG. 9. [Figure 11] It is a front view of the leg member 6a seen from the right side of FIG. 9. [Figure 12] It is a plan view of the leg member 6a. [Figure 13] It is a bottom view of the leg member 6a. [Figure 14] It is a cross-sectional view of the ashtray 41. [Figure 15] It is a flowchart for explaining an embodiment of a method for manufacturing a chair. [Figure 16A] It is a perspective view of the seat plate 3 seen from the side of the second surface 3b. [Figure 16B] It is a perspective view showing the state where the first member 5 is fixed to the seat plate 3. [Figure 16C] It is a perspective view showing the state where three leg members 6a, 6b, and 6c are attached to the first member 5 fixed to the seat plate 3. [Figure 16D] It is a perspective view showing the state where the chair 1 with the second member 7 fixed to the three leg members 6a, 6b, and 6c is inverted vertically.

Embodiments for Carrying Out the Invention

[0014] FIG. 1 is a front view showing the chair 1 of an embodiment of the present invention, FIG. 2 is a rear view of the chair 1, and FIG. 3 is a right side view of the chair 1. FIG. 4 is a perspective view of the chair 1 seen obliquely from above, FIG. 5 is a perspective view of the chair 1 seen obliquely from below, and FIG. 6 is a plan view of the chair 1. The chair 1 of the present embodiment may be used, for example, by worshippers in a cemetery. The chair 1 can be installed and used on an uneven installation surface 13 such as earth and sand or paving stones. The installation surface 13 is not limited to a cemetery, and may be an indoor installation surface such as a floor of a gymnasium, a floor covered with carpet in a lecture hall and a conference room, or an outdoor ground where the ground is exposed without paving, such as a playground, a construction site, and a park.

[0015] The chair 1 of the present embodiment includes a disk-shaped seat plate 3 having a first surface 3a that is circular in plan view, an annular first member 5 that is adhered to the second surface 3b on the opposite side of the first surface 3a of the seat plate 3, three rod-shaped leg members 6a, 6b, and 6c each having one end fixed to the first member 5, and an annular second member 7 that is fixed to an intermediate portion between one end and the other end on the opposite side of each of the three leg members 6a, 6b, and 6c and has a larger diameter than the first member 5.

[0016] The seat board 3, the first member 5, each leg member 6a, 6b, 6c, and the second member 7 are made of wood. The three leg members 6a, 6b, 6c are made of rectangular timbers with a cross-section perpendicular to the axis L2 extending in the longitudinal direction. Hardwood such as beech is preferred as the timber. Each leg member 6a, 6b, 6c is not limited to a rectangular timber with a cross-section perpendicular to the axis L2; ​​other shapes such as circular or elliptical cross-sections can be appropriately selected and used. In addition, each leg member 6a, 6b, 6c may taper from one end to the other. This makes it possible to lighten the chair 1.

[0017] For the materials of each leg member 6a, 6b, and 6c, Douglas fir may be used instead of the aforementioned beech wood. Douglas fir has a high oil content, excellent water resistance for outdoor use, and high durability, so a highly durable chair 1 can be obtained.

[0018] The seat plate 3 is disc-shaped, and its radius r1 centered on the central axis L1 is 300 mm or more and 400 mm or less, preferably selected to be about 350 mm. The thickness T1 of the seat plate 3 is 25 mm or more and 35 mm or less, preferably selected to be about 30 mm. The first surface 3a of the seat plate 3 has an annular groove 8 near the outer edge when viewed from above. The groove 8 has a radial width of 1 mm or more and 3 mm or less, and may have a depth of 1 mm or more and 3 mm or less parallel to the central axis L1 extending from the first surface 3a to the second surface 3b. The first surface 3a has an annular first portion 31 with a width r4 perpendicular to the central axis L1, located radially inward from the groove 8; an annular second portion 32 with a width r5 perpendicular to the central axis L1, located radially outward from the groove 8; and a circular third portion 33 with a radius r6 located radially inward from the first portion 31. The width r4 may be, for example, 20 mm, the width r5 may be, for example, 30 mm, and the radius r6 may be, for example, approximately 140 mm.

[0019] The third portion 33 forms a concave curved surface that is open and facing upward. The radius of curvature R of this curved surface is selected, for example, to be between 600 mm and 1000 mm. Since the seat plate 3 has a first portion 31, a second portion 32, a groove 8 between the first portion 31 and the second portion 32, and a third portion 33, the user can approach the first surface 3a from any position around the second surface 3a by moving their body the shortest distance and can easily and stably sit on the first surface 3a.

[0020] Furthermore, since the seat plate 3 has a groove 8 on the first surface 3a side, it can generate a frictional force in a direction that resists the movement of the user's buttocks when they are seated on the first surface 3a. This suppresses the inadvertent movement of the buttocks on the first surface 3a after sitting down, providing a stable seating experience. In addition, since the third portion 33 is a concave curved surface that opens upward, the buttocks are less likely to move even when the user changes their posture, providing a stable seating experience.

[0021] Since the seat plate 3 has a first portion 31, a groove 8, a second portion 32, and a third portion 33, when the user sits on the first surface 3a, they can intuitively perceive the amount of deviation of their center of gravity from the central axis L1 due to slight changes in the shape of the first portion 31, the groove 8, the second portion 32, and the third portion 33. This allows the user to adjust their seating position to the most stable position for their body and guide them to sit in that most stable position.

[0022] The curved surface of the third part 33 may be composed of, for example, a portion of a sphere with a radius of curvature R. By the third part 33 being composed of a portion of a sphere, the position of the central axis L1 becomes the deepest point relative to the first part 31 and the second part 22, and the user's seating position can be guided so that the center of gravity of the user's body is located approximately on the central axis L1. This improves the safety of the user's seating position, and the user can obtain a safe seating position.

[0023] Figure 7 is a cross-sectional view taken along the line VII-VII of the cross-section in Figure 6, and Figure 8 is a bottom view of chair 1. Each of the three leg members 6a, 6b, and 6c has a first notch 9 into which at least the outer circumference of the first member 5 partially fits, and a second notch 10 into which at least the outer circumference of the second member 7 partially fits. The radius (outer diameter) r2 of the first member 5 may be, for example, 225 mm or more and 255 mm or less, preferably about 235 mm. The radius (outer diameter) r3 of the second member 7 may be, for example, 295 mm or more and 315 mm or less, preferably about 305 mm.

[0024] Therefore, the second member 7 has a larger diameter (r3 > r2) than the first member 5, and each leg member 6a, 6b, 6c is arranged radially on a virtual plane containing the central axis L1, inclined at an inclination angle θ defined by the first member 5 and the second member 7. The inclination angle θ is the angle made between the central axis L2 of each leg member 6a, 6b, 6c and the central axis L1. The inclination angle θ is, for example, 2° or more and 7° or less, and preferably about 5°. By adopting such an inclination angle θ, it is possible to obtain an excellent aesthetic design, and even if the center of gravity of the chair 1 shifts relative to the central axis L1 due to changes in the user's seating position and posture, a larger amount of shift is permitted, allowing the user to sit stably on the installation surface 13, and thus improving stability.

[0025] Furthermore, since the three leg members 6a, 6b, and 6c are positioned at an inclination angle θ, in a plan view, the other ends of each leg member 6a, 6b, and 6c protrude radially outward from the outer edge of the seat plate 3. This ensures that even if the user's center of gravity shifts off-center from the central axis L1 of the chair 1 due to changes in the user's posture or shift in seating position, the user can still enjoy a stable seating experience.

[0026] The materials for the first member 5 and the second member 7 are, for example, multilayer boards made by bending a laminated board of three layers of veneer into a cylindrical shape. Since the three leg members 6a, 6b, and 6c are fixed at 120° intervals in the circumferential direction with respect to the central axis L1, the load on each leg member 6a, 6b, and 6c is distributed by the first member 5 and the second member 7. For example, even if the chair 1 is accidentally dropped and one of the three leg members 6a, 6b, and 6c comes into contact with the mounting surface 13 and a large impact force is applied, that impact force is distributed by the first member 5 and the second member 7 to the remaining two leg members that are not in contact with the mounting surface 13 and is also transmitted to the seat plate 3. This prevents a large load from concentrating on only one leg member that is in contact with the mounting surface 13, which would cause that leg member to deform or break, and provides high resistance to impact forces.

[0027] With the first member 5 fitted into the first notches 9 of each leg member 6a, 6b, and 6c, the first member 5 is fixed to the leg members 6a, 6b, and 6c by wood screws 11, which are first fasteners, screwed in from the radially inward direction. The first member 5 is supported by the bottom surface 9a of the notches of each leg member 6a, 6b, and 6c, and the upper surface 5a of the first member 5 is bonded to the bottom surface of the annular groove 15 of the seat plate 3. Therefore, the first member 5 is sandwiched between the bottom surface of the annular groove 15 of the seat plate 3 and the bottom surface 9a of the notches of each leg member 6a, 6b, and 6c, and is fixed with high strength.

[0028] The second member 7 fits into the second notches 10 of each leg member 6a, 6b, and 6c, and is fixed to each leg member 6a, 6b, and 6c by wood screws 12, which are second fasteners, screwed in from the radially inward direction. When the second member 7 is fixed to each leg member 6a, 6b, and 6c, the upper surface 7a of the second member 7 is supported by the lower surface 10a of the second notch 9. As a result, the forces acting on each leg member 6a, 6b, and 6c are distributed by the second member 7, preventing a large force from concentrating on just one of the three leg members 6a, 6b, and 6c, and reducing excessive load on each leg member 6a, 6b, and 6c. Furthermore, by fixing the second member 7 to the intermediate portion of each leg member 6a, 6b, and 6c, a large rotational torque is suppressed from acting on the joint between the first member 5 and one end of each leg member 6a, 6b, and 6c by the wood screw 11, thereby maintaining a secure attachment between each end of each leg member 6a, 6b, and 6c and the first member 6.

[0029] On the second surface 3b side of the seat plate 3, an annular groove 15 into which one end face portion of the first member 5 fits, and a first recess 14a, a second recess 14b, and a third recess 14c into which the end faces of one end of each leg member 6a, 6b, and 6c can fit are formed. Adhesive is applied to the end face of one end of each leg member 6a, 6b, and 6c, and when fitted into the recesses 14a, 14b, and 14c, it is bonded to the inner surfaces of the first recess 14a, the second recess 14b, and the third recess 14c.

[0030] In this way, one end of each leg member 6a, 6b, 6c is bonded to the inner surface of the seat board 3 that is exposed in the recesses 14a, 14b, 14c, thereby fixing each leg member 6a, 6b, 6c to the seat board 3. As the adhesive used to bond each leg member 6a, 6b, 6c to the seat board 3, a woodworking adhesive, such as a polyvinyl acetate adhesive, or other structural adhesives may be used. By bonding one end of each leg member 6a, 6b, 6c to the seat board 3, even if each leg member 6a, 6b, 6c shrinks due to drying, it is prevented from creating a gap between one end of each leg member 6a, 6b, 6c and the seat board 3, and a secure fixed state can be maintained.

[0031] Figure 9 is a side view of leg member 6a, Figure 10 is a rear view of leg member 6a viewed from the left side of Figure 9, Figure 11 is a front view of leg member 6a viewed from the right side of Figure 9, Figure 12 is a top view of leg member 6a, and Figure 13 is a bottom view of leg member 6a. Since the three leg members 6a, 6b, and 6c are configured symmetrically with respect to a virtual plane containing the central axis L1, we will explain one leg member 6a and omit the explanation of the remaining leg members 6b and 6c.

[0032] The leg member 6a has a first side surface 61, a second side surface 62, a back surface 63, a first surface 64, and a second surface 65, and is made of a rectangular timber with a pentagonal cross-section perpendicular to the axis L2 of the remaining portion excluding the aforementioned first notch 9 and second notch 10. The first side surface 61 and the second side surface 62 are parallel, and the back surface 63 is perpendicular to the first side surface 61 and the second side surface 62. The first surface 64 and the second surface 65 form a predetermined angle α. The predetermined angle α is selected, for example, from 90° to 170°, and preferably from 160°. The first surface 64 and the second surface 65 are connected via an edge 66.

[0033] The remaining leg members 6b and 6c are constructed in the same manner as the aforementioned leg member 6a. The chair 1 is fixed to the seat plate 3 with the sides 66 of each leg member 6a, 6b, and 6c facing radially outward with respect to the central axis L1. This results in a larger cross-section for each leg member 6a, 6b, and 6c compared to a case where the first surface 64 and second surface 65 of each leg member 6a, 6b, and 6c are a single plane, and therefore has a larger second moment of area, allowing it to withstand bending loads, compressive loads, and tensile loads with greater strength.

[0034] Figure 14 is a cross-sectional view showing the ashtray 41. The chair 1 of this embodiment further includes the ashtray 41. As shown in Figure 4, the ashtray 41 can be detachably attached to the second member 7 of the chair 1. The ashtray 41 has a thin, bottomed cylindrical ashtray body 42 and a hook member 43 fixed to the ashtray body 42. The ashtray body 42 has a disc-shaped bottom 44, a short cylindrical frame 45 bonded to one surface 44a of the bottom 44 with adhesive, and a decorative cover 46 made of resin attached to the bottom 44 and the frame 45.

[0035] The hook member 43 is made of metal and is formed by bending a strip of metal plate. The hook member 43 has a first portion 43a, a second portion 43b that is bent at a right angle to the first portion 43a, a third portion 43c that is bent at a right angle to the second portion 43b, a fourth portion 43d that is bent at a right angle to the third portion 43c, and a fifth portion 43e that is bent at a right angle to the fourth portion 43d. The decorative cover portion 46 has an annular surface portion 46a that is bonded to one surface of the frame portion 45, and a cylindrical outer peripheral portion 46b that is bent at a right angle to the outer circumference of the surface portion 46a and bonded to the bottom portion 44 and the outer peripheral surface of the frame portion 45.

[0036] The bottom portion 44 has a through hole 50 into which the first portion 43a of the hook member 43 can be inserted. The first portion 43a is inserted into the through hole 50, the second portion 43b contacts the opposite surface of the bottom portion 44, and the third portion 43c contacts the outer peripheral portion 46b of the decorative cover portion 46, and is fixed to the frame portion 45 by wood screws 51.

[0037] The third portion 43c and the fifth portion 43e are separated by the fourth portion 43d by a gap ΔL that is approximately equal to the thickness T2 of the second member 7. The approximately equal gap ΔL is a dimension slightly larger than the thickness T2 of the second member 7, such that the arc-shaped second member 7 can be manually fitted between the third portion 43c and the fifth portion 43e and removed manually from the fitted state. This allows the ashtray 41 to be detachably attached to the second member 7 by the hook member 43.

[0038] The hook member 43 may be configured to resiliently clamp the second member 7 with the third portion 43c and the fifth portion 43e. This prevents the ashtray 41 from easily detaching from the second member 7 due to contact with the user's leg, and prevents the contents, such as cigarette butts, from falling onto the installation surface 13.

[0039] The surface portion 46a of the decorative cover portion 46 has an opening 48 having the same inner diameter as the inner diameter of the inner circumferential surface 47 of the frame portion 45. The ashtray 41 has a space 49 formed by the aforementioned opening 48, the inner circumferential surface 47 of the frame portion 45, and the surface of the bottom portion 44 on which the frame portion 45 is provided. The space 49 is open upward when the ashtray 41 is hooked onto the second member 7 by the hook member 43, and can contain cigarette ash, cigarette butts, etc. when smoking.

[0040] The material for the cover portion 46 may be a heat-resistant synthetic resin, such as epoxy resin. This prevents the decorative cover portion 46 from easily igniting due to the heat from the cigarette ignition point during smoking. The material for the bottom portion 44 and the frame portion 45 may be beech wood. By using beech wood, for example, scraps generated when creating the seat plate 3 can be utilized.

[0041] In this embodiment of the chair 1, the first member 5 and the second member 7 are fixed to the three leg members 6a, 6b, and 6c, and one end of each leg member 6a, 6b, and 6c is fixed to the seat plate 3, thus providing a chair 1 that is comfortable to sit on and has high strength. Furthermore, even if the installation surface 13 of the chair 1 is not flat but has irregular undulations due to soil or other materials, it can be installed more stably on the installation surface 13 compared to a chair with four or more leg members. Moreover, since the first member 5 and the second member 7 are fixed to the three leg members 6a, 6b, and 6c, the three leg members 6a, 6b, and 6c are connected with high strength and can be integrated with the seat plate 3. As a result, even if the chair 1 is accidentally dropped during transport or comes into contact with another object, deformation or damage to the chair 1 is suppressed, and a chair 1 with excellent resistance to impact force can be obtained.

[0042] Furthermore, the user can easily and stably sit on the backless seat by moving their body in the shortest distance relative to the seat from any direction, providing a chair with excellent usability.

[0043] Because the seat plate 3, the first component 5, the three leg components 6a, 6b, and 6c, and the second component 7 are made of wood, a chair 1 with a moderate weight can be obtained compared to those made of metal or synthetic resin, preventing the chair 1 from tipping over in strong winds. Furthermore, because the seat plate 3, the first component 5, the three leg components 6a, 6b, and 6c, and the second component 7 are made of wood, even when the chair 1 is used for visiting graves, it will have a wooden appearance, so there will be no qualitative incongruity, and a chair with excellent design aesthetics can be provided.

[0044] (Manufacturing method) Figure 15 is a flowchart illustrating one embodiment of the manufacturing method of chair 1. Figure 16A is a perspective view of the seat plate 3 viewed from the second surface 3b side, Figure 16B is a perspective view showing the state in which the first member 5 is fixed to the seat plate 3, Figure 16C is a perspective view showing the state in which the three leg members 6a, 6b, and 6c are attached to the first member 5 fixed to the seat plate 3, and Figure 16D is a perspective view showing the chair 1 inverted vertically, with the second member 7 fixed to the three leg members 6a, 6b, and 6c.

[0045] In this embodiment, the method for manufacturing a chair begins with the preparation step S0, at which point the manufacturing of the chair 1 is initiated. The process then moves from the start step S0 to the first step S1. In the first step S1, the material for the seat plate 3 is prepared. As shown in Figure 16A, the material for the seat plate 3 is processed into a disc shape. On the first surface 3a, a first portion 31, an annular groove 8, a second portion 32, and a third portion 33 are formed. On the second surface 3b, an annular groove 15, a first recess 14a, a second recess 14b, and a third recess 14c are formed. The first recess 14a, the second recess 14b, and the third recess 14c are formed at equal intervals in the circumferential direction with respect to the central axis L1, protruding radially outward from the annular groove 158.

[0046] Once the seat plate 3 is prepared in the first step S1, the process moves to the second step S2. In the second step S2, the annular first member 5 is prepared. Once the first member 5 is prepared, the process moves to the third step S3. In the third step S3, the second member 7 is prepared. Once the second member 7 is prepared, the process moves to the fourth step. In the fourth step S4, three leg members 6a, 6b, and 6c, each having a first notch 9 and a second notch 10, are prepared. The order in which these first member 5, second member 7, and three leg members 6a, 6b, and 6c are prepared is not limited to the second step S2, third step S3, and fourth step S4, and can be changed as appropriate as long as the seat plate 3, first member 5, second member 7, and three leg members 6a, 6b, and 6c are prepared by the fifth step S5.

[0047] Once the seat plate 3, first member 5, second member 7, and three leg members 6a, 6b, and 6c are prepared in steps 1 S1 to 4 S4, the process moves to step 5 S5. In step 5 S5, as shown in Figure 16B, one annular end face of the first member 5 is fitted into the annular groove 15 of the seat plate 3 and bonded. After applying adhesive to the annular groove 15, simply fitting one end face of the first member 5 into the annular groove 15 positions the first member 5 so that it is coaxial with the central axis L1 relative to the seat plate 3. This eliminates the need for positioning the first member 5 relative to the seat plate 3, thus simplifying the manufacturing process.

[0048] In the fifth step S5, when the first member 5 is bonded to the seat board 3, the process moves to the sixth step S6. In the sixth step S6, as shown in Figure 16C, three leg members 6a, 6b, and 6c are fixed to the seat board 3 to which the first member 5 is fixed. When attaching the three leg members 6a, 6b, and 6c to the seat board 3, adhesive is applied to the first recess 14a, the second recess 14b, and the third recess 14c of the seat board 3, respectively. Then, the end faces of one end of the leg members 6a, 6b, and 6c are fitted into the first recess 14a, the second recess 14b, and the third recess 14c, and the outer circumference of the first member 5 is fitted into the first notch 9. The first member 5 is then fixed to each leg member 6a, 6b, and 6c with wood screws 11. As a result, each leg member 6a, 6b, and 6c is positioned in a direction in which each axis L2 is inclined at an angle θ with respect to the central axis L1, eliminating the need for positioning each leg member 6a, 6b, and 6c relative to the seat plate 3, thus simplifying the manufacturing process.

[0049] In the sixth step S6, when the first member 5 is fixed to the three leg members 6a, 6b, and 6c, the process moves to the seventh step S7. In the seventh step S7, as shown in Figure 16D, the chair 1 is manufactured by fitting the outer circumference of the second member into the second notches 10 of the three leg members 6a, 6b, and 6c and fixing it with wood screws 12, which are the second fasteners. In the final step S8, the manufacturing of the chair 1 is completed.

[0050] In the above-described embodiment, the first member 5 and the first notches 9 of the three leg members 6a, 6b, and 6c were fixed with wood screws 11, and the second member 7 and the second notches 10 of the three leg members 6a, 6b, and 6c were fixed with wood screws 12. However, in other embodiments of the present invention, the first and second fasteners are not limited to wood screws 11 and 12, but may be composed of wooden pins and pinholes. In this case, pinholes may be provided in the first member 5 and the second member 7, and pinholes may also be provided in the first notches 9 and the second notches 10 of the three leg members 6a, 6b, and 6c, and the pins may be driven into the pinholes of the first member 5 and the second member 7 and fitted into the pinholes of the first notches 9 and the second notches 10. Furthermore, the pins are not limited to wood, but may be made of bamboo or metal.

[0051] In the embodiment described, the cross-section perpendicular to the central axis L1 of the three leg members 6a, 6b, and 6c is pentagonal. However, in other embodiments, the frontal shapes of the first surface 64 and the second surface 65 may be polygonal with three or more faces, semicircular, or semielliptical. In such a configuration, the same effects as in the above embodiment are achieved, namely, compared to the case where the first surface 64 and the second surface 65 of each leg member 6a, 6b, and 6c have a quadrilateral cross-section on a single plane, the cross-section of the members is larger, and they can withstand loads with greater strength.

[0052] Although embodiments of the chair and its manufacturing method according to the present invention have been described in detail above, the present invention is not limited to the embodiments described above, and various modifications and improvements are possible without departing from the spirit of the invention. It goes without saying that all or part of each of the above embodiments can be combined as appropriate and in a non-contradictory manner. [Explanation of Symbols]

[0053] 3 Seat board 3a 1st page 3b 2nd side 5. First Member 6a,6b,6c Leg members 7. Second Member 7a Top side 8. Grooves 9 First notch 9a Notched bottom 10 Second notch 10a Notched bottom surface 11,12 Wood screws 14a First recess 14b Second recess 14c 3rd recess 31 Part 1 32 Part 2 33 Part 3 41 Ashtray 42 Ashtray body 43 Hook member 44 Bottom 45 Frame section L1 center axis r1,r2,r3 radius r4,r5,r6 width T1 Thickness

Claims

1. A disc-shaped seat plate having a first surface which is the seat surface, An annular first member fixed to the second surface of the seat plate opposite to the first surface, The first member has three leg members, each fixed to one end by a first fastener at intervals in the circumferential direction, and extending in a direction in which the distance between them increases as they move away from the second surface perpendicularly, The leg members are fixed by a second fastener to the intermediate portion between one end and the other end opposite to the first end, and include an annular second member having a larger diameter than the first member, Each of the three leg members has a first notch that partially fits into the outer circumference of the first member, and a second notch that partially fits into the outer circumference of the second member. A chair characterized in that the seat plate, the first member, the three leg members, and the second member are made of wood.

2. The chair according to claim 1, characterized in that the first member and the second member are made of a multilayer board formed by laminating a plurality of plywoods.

3. A method for manufacturing a wooden chair, The first step is to prepare a disc-shaped seat plate having a first surface which is a seating surface and a second surface opposite to the first surface, the second surface having an annular groove and a first recess, a second recess, and a third recess formed at intervals from each other around the central axis of the groove, The second step involves preparing a first ring-shaped member, A third step involves preparing a second annular member having a larger diameter than the first member, A fourth step is to prepare three leg members, each having a first notch into which the outer periphery of the first member can be partially fitted, and a second notch into which the outer periphery of the second member can be partially fitted. A fifth step involves applying adhesive to the groove of the seat plate, and fitting one annular end face of the first member into the groove to which the adhesive has been applied and bonding it, A sixth step involves fitting the outer periphery of the first member into the first notches of the three leg members, inclining the three leg members in a direction that widens the distance between them as they move away from the second surface, and fixing the first member to the three leg members with the first fastener. A method for manufacturing a chair, comprising a seventh step of partially fitting the outer periphery of the second member into the second notch of the three leg members and fixing the second member to the three leg members with a second fastener.

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