Elbow rest and chair equipped with the same

Abstract

To provide an arm rest that is superior in an exterior appearance because screws for fixing are not exposed at the time when attaching a panel to an elbow body having a frame-like part.SOLUTION: A chair 100 comprises: an elbow body 61 mounted at a main body of the chair, and having a frame-like part 62; and a panel 66 mounted to an opening 62A of the frame-like part 62. An arm rest 60 is characterized in that a concave hole 65 is disposed as a recess being at least one first locking part in an inner circumferential surface of the opening 62A, and a shoulder screw 69 is disposed as a protrusion being a second locking part paired with the first locking part in the outer circumferential surface of the panel 66. The chair 100 with this is provided.SELECTED DRAWING: Figure 1

Description

Technical Field

[0004] ,

[0005] , ,

[0001] The present invention relates to an armrest attached to a chair and a chair including the same, and more particularly to an armrest having an excellent appearance and a chair including the same.

Background Art

[0002] Conventionally, a chair to which an armrest including an elbow body formed with a frame portion is attached has been known. As a modification of such an armrest, a configuration in which a panel is attached to an opening of the frame portion is also known. As an example of the configuration when attaching a panel to the opening of such a frame portion, Patent Document 1 (Japanese Patent Application Laid-Open No. 2001-321242) has been proposed by the applicant. <000001]0>[[ID=]14]

Prior Art Document

Patent Document

[0003] <0>000016>

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The armrest disclosed in Patent Document 1 employs a configuration in which, after attaching a core material so as to span an opening of a frame portion and sandwiching the core material between two panels, the panels are fixed to the core material using screws from the outer surfaces of the respective panels. Although this configuration enables the panels to be attached and detached reliably and easily, there is a problem that the screws for fixing the panels to the core material are exposed and the appearance is not excellent.

Means for Solving the Problems

[0005] Therefore, in the present invention, when attaching a panel to an elbow body having a frame portion, an object is to provide an armrest with an excellent appearance and a chair including the same without exposing the screws for fixing the elbow body and the panel.

[0006] In other words, the present invention is an armrest comprising an armrest body attached to the body of a chair and having a frame-shaped portion, and a panel fitted into the opening of the frame-shaped portion, wherein at least one first locking portion is provided on the inner circumferential surface of the opening, and a second locking portion paired with the first locking portion is provided on the outer circumferential surface of the panel.

[0007] This eliminates the need for screws to secure the armrest body to the panel, resulting in no exposed screws on the panel surface and providing an armrest with a superior appearance.

[0008] Furthermore, it is preferable that the first locking portion is a recess or a protrusion, and it is even more preferable that the recess is a machined hole, and the protrusion is formed by the large diameter portion and screw head portion of a stepped screw that is erected on the inner circumferential surface of the opening or the outer circumferential surface of the panel.

[0009] These features allow for a simplification of the configuration of the first and second locking parts, reducing manufacturing costs, improving the dimensional accuracy of the engaging parts, and enhancing the accuracy of attaching the panel to the elbow body.

[0010] Furthermore, it is preferable that screws are screwed from the outer circumferential surface of the frame-shaped portion to the frame-shaped portion at positions opposite to the positions where the first and second locking portions are located, and it is even more preferable that the first locking portion is located on the lower, front, or rear side of the inner circumferential surface of the opening, the second locking portion is located on the lower, front, or rear side of the inner circumferential surface of the panel, and that the screws are covered by a cover attached to the outer circumferential surface of the frame-shaped portion.

[0011] These features allow for a stronger fixation of the panel to the elbow joint. Furthermore, when screws are used to secure the panel to the elbow joint, the cover attached to the elbow joint prevents the screws from being exposed, thus achieving both improved fixing strength and a better appearance.

[0012] Furthermore, it is preferable that the opening is formed in a frustum shape that gradually narrows outward from the seat side.

[0013] Furthermore, it is preferable that the outer diameter of the inner surface material, which is the seating surface side, and the outer diameter of the outer surface material, which is the outer surface, are different.

[0014] As a result, the panel attached to the elbow joint can be prevented from falling off the elbow joint during normal use without the need for fixing screws.

[0015] Furthermore, the chair of the present invention is characterized by being equipped with an armrest as described in any of the above. [Effects of the Invention]

[0016] According to the configuration of the armrest and chair equipped therewith in the present invention, when attaching a panel to the armrest body having a frame-like portion, the screws for fixing the armrest body and the panel are not exposed, making it possible to provide an armrest and chair equipped therewith with an excellent appearance. [Brief explanation of the drawing]

[0017] [Figure 1] This is a front perspective view showing a chair with armrests attached according to this embodiment. [Figure 2] This is a rear perspective view showing a chair with armrests attached according to this embodiment. [Figure 3] This is a perspective view showing the chair shown in Figure 1 with the leg supports, right armrest, and backrest removed. [Figure 4] This is an exploded view of Figure 3 with the left armrest removed. [Figure 5] This is a perspective view of the seat support member. [Figure 6] This is an exploded view of the backrest support member and the backrest itself. [Figure 7] This is a detailed diagram of the back mounting section. [Figure 8] It is a side view of the back frame. [Figure 9] It is a front perspective view of the back frame. [Figure 10] It is a perspective view from the lower rear of the back shell. [Figure 11] It is a perspective view showing the elbow body of the armrest in this embodiment. [Figure 12] It is a perspective view showing the panel in this embodiment. [Figure 13] It is a perspective view showing the state where the inner surface material and the stepped screw are removed from the panel shown in FIG. 12. [Figure 14] It is a perspective view showing the attachment situation of the panel shown in FIG. 12 to the opening of the elbow body shown in FIG. 11. [Figure 15] It is a perspective view showing the attachment situation of the screw for fixing the elbow body and the panel. [Figure 16] It is a cross-sectional view showing the internal structure of the armrest in the state where the fixing screw is attached. [Figure 17] It is a perspective view of the armrest in this embodiment.

Mode for Carrying Out the Invention

[0018] Hereinafter, the configuration of the present invention will be described in detail based on the embodiments shown in the drawings. In this specification, the front-back, left-right directions are defined centering on the seated person. That is, "front or forward" means the front or forward for the chair 100 and the seated person in each of the seat �0 and the backrest 50, and "rear or backward" means the rear or backward for the chair 100 and the seated person in the same way. Further, the direction orthogonal to the front-back direction in the horizontal plane is the left-right direction for the seated person in each of the seat 30 and the backrest 50, and is also the width direction of the chair 100. Furthermore, "up" and "down" are the up and down for the chair 100 and the seated person in each of the seat & and the backrest 50, and are the up and down in the vertical plane.

[0019] Figures 1 and 2 show one embodiment of a chair 100 equipped with the armrest 60 of the present invention. The chair 100 in this embodiment comprises a leg support 10, a main frame 20 attached to the leg support 10, a seat 30 and a backrest support member 40 pivotably connected to the main frame 20, a backrest 50 attached to the backrest support member 40, and an armrest 60. A headrest 55 is attached to the backrest 50. The armrest 60 is detachably attached to the rear bridge frame 41 by screws.

[0020] (Leg support 10) In this embodiment, the leg support column 10 has casters 11 attached to each of its ends, and each of its base ends is attached radially to the lower end of the leg support column 10 in a plan view, and has five leg vanes 12. In addition, the leg support column 10 in this embodiment has a built-in lifting mechanism (not shown) for extending and retracting the leg support column 10 in the height direction. This lifting mechanism is operated by operating a lifting lever 37 located at the right end of the front bridge frame 33. As shown in Figures 1, 3, and 4, the main frame 20 is attached to the upper end of the leg support column 10 formed in this way.

[0021] (Mainframe 20) The main frame 20 has a backrest support member 40 pivotably connected to a bracket 21 located at the rear, for attaching the backrest 50, and a seat support member 31 pivotably connected to a front link 23 located at the front, for attaching the seat 30. The main frame 20 is box-shaped to increase the mechanical rigidity of the structure (especially torsional rigidity, etc.) and to house a reaction force mechanism (not shown) inside. This reaction force mechanism generates a force that pushes the backrest 50 back in conjunction with the backward tilt of the backrest 50 between the backrest support member 40 pivotably supported at the rear end of the main frame 20 and the link shaft at the front end of the main frame 20 (in this embodiment, this also serves as an operating shaft for adjusting the reaction force: not shown).

[0022] The main frame 20 is supported by the leg support 10 by the fitting of a gas spring on the leg support 10 into a cylindrical portion 29 on its rear lower surface. A shaft hole 25 is formed in a bracket 21 erected on the rear upper surface, and the bearing portion 44 of the rear bridge frame 41 is connected to this shaft hole 25 via a backrest rotation shaft SJ (see Figure 1), thereby pivotably supporting the seat portion 30 and the backrest support member 40 (backrest 50). A pair of left and right front links 23 are arranged in front of the main frame 20. The bearing portion 33A of the front bridge frame 33, which supports the seat frame 32, is rotatably connected via the front links 23. The main frame 20 in this embodiment is integrally molded from aluminum die-cast or the like, but is not limited to this, and may be molded from steel or the like by welding into a box shape or other shape having a bearing portion. Furthermore, a switching lever 27 for switching between the oscillation and fixing of the front link 23 is provided on the right side of the main frame 20. Inside the main frame 20, a reaction force mechanism including a compression coil spring is provided. Since this reaction force mechanism can adopt a known configuration disclosed in Japanese Patent Application Publication No. 2021-61967, a detailed explanation is omitted here.

[0023] In this embodiment, as shown in Figure 3, the front link 23 is formed on a surface that is almost identical to the surfaces (side, bottom, and top) that make up the main frame 20, and is designed to appear as if it is part of the main frame 20 when viewed from the side. For example, it has a top section (not shown) and a bottom section (not shown) that close the space between the left and right front links 23 without interfering with the bearing section 33A, etc., and provides design continuity with the main frame 20. The main frame 20 and the front link 23 are elements that appear as a single, sleek mass that becomes thinner towards the tip, but are actually separated into parts, the front link 23 and the main frame 20, by grooves cut in a semicircular shape. Specifically, for example, the tip side is formed in an oval shape with a smaller diameter than the base side and becomes thinner towards the tip overall. The top surface of the main frame 20 is made up of a main frame top cover (not shown).

[0024] The positional relationship between the main frame 20 and the front link 23 is such that they are positioned on a single axis in the initial position (when no one is seated). In other words, the main frame 20 is positioned so that it extends along the extension of the line connecting the front end of the front link 23 and the backrest rotation axis SJ. This design consideration gives the impression of a single component and a clean, streamlined appearance. In this way, the mechanical parts under the seat can be made smaller and thinner, improving space efficiency and resulting in a smart, aesthetically pleasing appearance.

[0025] (Seat 30) The seat portion 30 is not limited to a specific structure and shape, but in this embodiment, as shown in Figures 3 to 5, it is a so-called fully enclosed seat structure in which the inner shell 35 is completely covered with cushioning material 36 and a bag-shaped upholstery (not shown), and is pivotably mounted on the main frame 20 via a seat support member 31.

[0026] The seat support member 31 of this embodiment has an annular seat frame (a rectangular frame with an open inner side) 32, a front bridge frame 33 that supports the front of the seat frame 32, and a bracket 34 for connecting the seat frame 32 to the backrest support member 40 at a position slightly rearward from the middle. The bearing portion 33A in the central part of the front bridge frame 33 is pivotably connected to and supported by the front link 23 of the main frame 20, while the bracket 34 on the rear side of the seat frame 32 is pivotably connected to the bracket 47 of the backrest support member 40 by a pivot shaft (not shown) and supported. Therefore, the seat portion 30 moves in conjunction with the movement of the backrest 50.

[0027] The front bridge frame 33 is a curved, wing-shaped frame with a convex central section that extends downwards and upwards on both sides. Together with the rear bridge frame 41 and back shell mounting portion 42 of the backrest support member 40, it creates space beneath the seat (see Figures 3 and 4). This allows the mesh and cushions that make up the seat structure to flex vertically without being obstructed. It also has the effect of making the design appear lighter.

[0028] Here, the mounting position of the rear bracket 34 of the seat frame 32 to the rear bridge frame 41 is located in front of the backrest rotation axis (i.e., the axis hole 25) of the rear bridge frame 41, and is positioned to lift the seat frame 32 (i.e., the seat portion 30) when the backrest support member 40 tilts backward. In other words, the seat portion 30 is lifted as the backrest 50 tilts backward, and a portion of the seater's weight acts as resistance to the backward tilting movement of the backrest 50 (the rocking resistance is weight-sensitive), thus constituting a weight-sensitive reaction force application mechanism (or weight-sensitive reaction force application mechanism).

[0029] On the other hand, in this embodiment, the seat structure, prioritizing comfort, consists of an annular inner shell (core) 35 stretched with mesh (not shown) as a structural member that evenly distributes and supports the weight of the sitter, a cushioning material 36 such as urethane foam placed on top of the mesh of the inner shell 35, and upholstery (not shown) that wraps the cushioning material 36 and the inner shell 35. It is placed on the seat frame 32 (corresponding to the outer shell) and fixed in place by screws from below, for example, through screw holes 39. The upholstery in this embodiment is of the type that has, for example, a loop for threading a string around the periphery, and the cushioning material 36 and the inner shell 35 are wrapped by pulling the string to tighten the upholstery, which requires finishing the ends of the string. Therefore, an annular string groove 35A (see Figure 5) is provided in the center of the upper surface of the seat frame 32 to accommodate the wrapping string, and the string (not shown) is stored in the string groove 35A of the seat frame 32 so that it is not visible. Of course, not only the strings, but the edges of the upholstery itself can be enclosed within the string groove 35A so that they are not visible. Furthermore, while the seat structure in this embodiment uses a double elastic support structure of mesh and urethane to improve seating comfort, it is not limited to this, and elasticity can be provided by using only urethane or only mesh.

[0030] In this embodiment, the front bridge frame 33 and the seat frame 32, as well as the rear bridge frame 41 and the back shell mounting portion 42, are integrally molded, but in some cases they may be molded separately and then connected.

[0031] (Lifting lever 37) A cavity 38 is provided in the wall section rising towards the seat frame 32 at the right end of the front bridge frame 33, into which a lifting lever 37 for operating the opening and closing of the gas cylinder valve of the leg support column 10 is fitted. This streamlines the frame shape of the seat support member 31 and allows for a smart placement of the lifting lever 37. Furthermore, the routing of the operating wire W can be laid out along the front bridge frame 33. Moreover, instead of creating a lever receiver (box-shaped) on the frame itself, the lifting lever 37 is equipped by housing an independent lever in the cavity 38 of the front bridge frame 33, thereby reducing parts and assembly costs. The ball portion WT at the tip of the operating wire W is anchored to the ball receiving portion at the upper end of one side of an L-shaped link (a so-called bell crank; not shown) that is pivotably supported by a link holder (not shown), and is designed so that the other side pushes down the gas cylinder valve when the operating wire W is pulled.

[0032] (Backrest support member 40) As shown in Figures 3 and 6, the backrest support member 40 has a rear bridge frame 41 and an annular back shell mounting portion 42 (a rectangular frame with an open inner side). The rear bridge frame 41 is a curved, wing-shaped frame with a central portion that is convex downwards and extends upwards on both sides. Together with the rear annular back shell mounting portion 42, it creates a space under the seat at the rear of the seat portion 30. This allows the mesh and cushions that make up the seat structure (not shown) to flex vertically without being obstructed. It also has the effect of making the design appear lighter.

[0033] Furthermore, at the center of the lowest part of the rear bridge frame 41, as shown in Figures 3 and 6, there is a bearing portion 44 for inserting the backrest rotation axis SJ of the bracket 21 at the rear end of the main frame 20 and connecting it so that it can swing freely, and an arm portion 45 that hangs down diagonally downward and forward to receive and support one of the spring mounts (not shown) of the spring-type backrest reaction mechanism, and is provided to constitute a spring-type backrest reaction mechanism that pushes one of the spring mounts of the spring-type backrest reaction mechanism forward when the backrest 50 tilts backward. In addition, brackets 47, which are mounting portions for swingably attaching the rear bracket 34 of the seat frame 32, are provided at both ends of the upper surface of the rear bridge frame 41.

[0034] Here, as shown in Figures 3 and 6, the bracket 47 is positioned in front of the bearing portion (i.e., the shaft hole 25 which is the backrest rotation axis) 44, that is, in a position that lifts the seat portion 30 when the rear bridge frame 41 tilts backward. For example, the backrest support member 40 is inclined such that, when the bearing portion (i.e., the shaft hole 25 which is the backrest rotation axis) 44 of the rear bridge frame 41 is centered, the rear bridge frame 41 protrudes diagonally upward and forward, and the rear back shell mounting portion 42 of the rear bridge frame 41 is inclined to protrude diagonally upward and backward, so that the position is such that when the bearing portion (in other words, the shaft hole 25 which is the backrest rotation axis) 44 of the rear bridge frame 41 lifts the seat portion 30 when the backrest 50 is tilted backward.

[0035] Furthermore, as shown in Figures 3 and 6, armrest mounting seats 48 for attaching armrests 60 are provided at both ends of the rear bridge frame 41. When the armrests 60 are not present, these armrest mounting seats 48 are exposed as recesses and are covered by a cover, that is, a cover made of a surface that is flush with the outer shell surface of the rear bridge frame 41. However, the backrest support member 40 has a rational structure that integrates the rear bridge frame 41, bearing portion 44, arm portion 45, back shell mounting portion 42, seat frame mounting portion (bracket 47), and armrest mounting seats 48 into a single unit.

[0036] (Backrest 50) The backrest 50 is not limited to a specific structure or shape. As shown in Figure 6, the backrest 50 of this embodiment is composed of a back shell 51 and a back covering material (not shown), and employs a so-called full-coverage structure in which the back shell 51 is completely covered with cushioning material 54 and a bag-shaped upholstery (not shown). The headrest 55 has a main body part 55A and a fixing part 55B, and the fixing part 55B is fixed to the back side of the back plate 52 that constitutes the back shell 51 by screws. The back side of the headrest 55 is formed in a lattice shape, achieving both mechanical strength and lightness. The backrest 50 thus formed is pivotably mounted on the main frame 20 via a backrest support member 40.

[0037] In this embodiment, the backrest 50 is constructed by placing a flexible back plate 52 in the center of the back shell 51, and supporting both sides with rigid back frames 53, thereby covering the entire back. Specifically, as shown in Figure 6, the back shell 51 in this embodiment is composed of a pair of rigid back frames 53 and a flexible back plate 52, resulting in a component configuration that is rational in terms of strength.

[0038] As shown in Figure 6, the backrest 50 in this embodiment is formed in a shape that is convex towards the front in a side view (i.e., a V-shape), and is curved so as to be convex towards the rear in a plan view. The backrest mounting seat 56 at the lower end of the back shell 51 is fitted into the flange 43 of the back shell mounting portion 42 of the backrest support member 40 and screwed in, creating a continuous L-shape in side view. The screwing is done by screwing a screw (not shown) from the inside of the annular back shell mounting portion 42, so that the U-shaped back mounting seat 56 that protrudes forward of the back shell 51 is connected to the back shell mounting portion 42 and integrated without being visible from the outside. As a result, in this embodiment, the backrest support member 40 and the back shell 51 of the backrest 50 are configured to have a clean appearance with a continuous L-shape in side view.

[0039] As shown in Figure 7, the back mounting base 56 of the back shell 51 (i.e., the part that fits into the back shell mounting portion 42 of the back support member 40) is L-shaped in side view, bent forward, and the back frame portions 53 on both sides protrude further forward than the central back plate 52, forming a U-shape in plan view that surrounds the back shell mounting portion 42. The structure is designed to firmly connect to the back shell mounting portion 42 by being inserted and sandwiched from three directions: the left and right sides and the back.

[0040] The back frame 53 is preferably molded from glass fiber reinforced nylon such as PA6-GF (polyamide 6) to ensure mechanical rigidity as a structure. On the other hand, the back plate 52 is preferably made of a certain degree of flexibility to improve the comfort of leaning against it as a backrest 50, and is preferably molded from olefin resin such as PP (polypropylene). In other words, the strength of the backrest 50 is ensured by the back frames 53 on both sides, while the softness of the backrest 50 is ensured by the back plate 52 in the center.

[0041] In this embodiment, the back frame 53 has a vertically elongated shape, as shown in Figures 6 to 9, for example, and preferably extends to the lower left and right sides of the back plate 52, for example, to the majority of the back plate 52, for example, to the area above the back support point (the part that is pressed against the seated person's lower back). This allows it to function as a reinforcing member of the back shell 51. On the other hand, the back plate 52 is formed in a desired shape, for example, a roughly rectangular shape in front view with reinforcing edges provided, including the part to which the back frame 53 is attached.

[0042] The back plate 52 and the back frames 53 on both sides are connected and integrated by interlocking grooves parallel to the front surface of the backrest 50 and by screw fastening of the interlocking parts with screws. In this state, it is attached to the annular back shell mounting portion 42 at the rear of the backrest support member 40. Note that the reference numeral 52C in the figure indicates a screw hole.

[0043] To make the connection between the back frame 53 and the back plate 52 strong and smooth and continuous with minimal irregularities, steps 52A are provided on both side edges of the back plate 52, as shown in Figures 6 to 9. These steps 52A partially overlap with the back frame 53 (i.e., form a flange 52B), while a U-shaped fitting portion 53B is formed on the inner side surface of the back frame 53 facing the back plate 52, forming a groove 53A into which the flange 52B of the back plate 52 is fitted. In this way, the back plate 52 and the back frame 53 are integrated by fitting the flange 52B and the groove 53A together. The rigidity of the back frame 53 is further increased by the fact that the fitting portion 53B that overlaps with the back plate 52 has a U-shaped cross-sectional structure and can be bent into an L-shape. Moreover, the rigidity is further increased by fitting the flange 52B of the back plate 52 into the groove 53A. Furthermore, in this embodiment, the backrest 50 has a U-shaped fitting portion 53B that forms a groove 53A into which the flange 52B of the back plate 52 is fitted. A rear support portion 53C that wraps around to the rear side of the back plate 52 is projected inward from one edge portion (i.e., by changing its length). This provides a portion that overlaps with the back plate 52 in the front-rear direction, further increasing its strength. In this embodiment, the backrest 50 has a so-called all-over structure that completely covers the back shell 51, so the fitting portion between the flange 52B of the back plate 52 and the groove 53A of the back frame 53 is concealed.

[0044] On the other hand, the back mounting base 56 of the back shell 51 has a flange groove 56A formed therein, facing the back shell mounting portion 42 of the back support member 40. For example, as shown in Figures 6 to 10, it has a flange groove 56A in the center for fitting the flange 43 of the back shell mounting portion 42, and above and below it are grooves 56B for the front upholstery and grooves 56C for the back upholstery, respectively, for sandwiching the upholstery together with the locking member, such as a PP (polypropylene resin) cord sewn to the edge (i.e., the edge) of the upholstery.

[0045] In this embodiment, the back shell 51 is divided into three parts: the left and right back frames 53 and the central back plate 52. Since the die-cutting direction for each part is unidirectional, the mold structure does not need to use a sliding mold or the like, thus simplifying the mold structure and reducing costs.

[0046] Furthermore, a position is provided on the inner surface of the U-shaped back mounting base 56 on the side opposite to the top edge, i.e., the bottom edge, that can be fixed to the upholstery while applying tension to the full upholstery that covers the back shell 51 (see Figure 7). For example, on the outer surface of the bottom edge of the back shell 51 (the bottom edge of the back panel 52), two grooves for upholstery are formed, one above the other, into which the edges of the upholstery equipped with thin plate-shaped locking members are fitted. These grooves are a front upholstery groove 56B into which the front upholstery edge of the opening of the full upholstery is inserted, and a back upholstery groove 56C into which the back upholstery edge is inserted. This upholstery fixing structure prevents the locking members from coming out of the grooves even when tensile force is applied to the upholstery, as they catch on the grooves.

[0047] Furthermore, a flange groove 56A is formed between the front upholstery groove 56B and the back upholstery groove 56C, into which the flange 43 of the back shell mounting portion 42 is inserted. A vertical rib 56D is formed in the middle of this flange groove 56A, crossing the flange groove 56A (i.e., the flange groove 56A is formed intermittently), and the vertical rib 56D is provided with a female thread 56E for screwing the back shell mounting portion 42 in place. On the other hand, the flange 43 of the back shell mounting portion 42 is formed intermittently in the circumferential direction so that the flange 43 can be inserted into the flange groove 56A without interfering with the vertical rib 56D provided in the flange groove 56A. Therefore, the edges of the back walnut are hidden, resulting in a neat upholstery storage method, while also ensuring strong clamping and fixing strength for the upholstery.

[0048] In this embodiment, the grooves 56B for the front upholstery and 56C for the back upholstery are provided on the inner circumferential surface of the U-shaped back mounting base 56 of the back shell 51. However, they are not limited to this, and can be provided in any position where they can be fixed while tension is applied to the walnut. For example, they could be on the top edge of the back shell 51 or on the side. In addition, instead of using the back shell 51, the back may be placed over and fixed to a back frame (a hollow frame) not shown in the figure.

[0049] (Reaction mechanism: Weight-sensitive type) The chair 100 of this embodiment uses a combination of a reaction force mechanism, which is a spring-based reaction force mechanism that compresses the spring to obtain a reaction force when the backrest 50 is tilted backward, and a weight-sensitive (or sensing) reaction force application mechanism that, by linking the backrest 50 with the seat frame 32 to lift when the backrest 50 is tilted backward, makes the resistance to rocking of the backrest 50 proportional to (sensitive to) the user's weight. Since a known configuration can be adopted for such a reaction force application mechanism, a detailed explanation is omitted here.

[0050] (Armrest 60) An armrest 60 is attached to the armrest mounting base 48 of the backrest support member 40, which is the main body of the chair 100. In this embodiment, the armrest 60 has a panel 66 attached to a frame-shaped part 62 provided on the armrest body 61. The structure of the armrest 60 in this embodiment will be described below with reference to Figures 11 to 17. Although the armrests 60 are attached to the left and right positions of the seat 30, they have a symmetrical configuration, so only one armrest 60 will be described here. As shown in Figure 11, the armrest body 61 has a frame-shaped part 62 and a connecting arm 63 formed integrally with the frame-shaped part 62. In this embodiment, the opening 62A of the frame-shaped part 62 has a so-called inverted trapezoid shape, but the shape of the opening 62A is not particularly limited. In this embodiment, the opening 62A is formed in a frustum shape in which the outer opening surface 62Y is smaller than the inner opening surface 62X. Furthermore, two recessed holes 65, which serve as first locking portions, are formed on the lower inner circumferential surface of the opening 62A at required intervals. Such recessed holes 65 can be machined holes produced by a machine tool such as a milling machine, but are not limited to machined holes.

[0051] Next, the panel 66 to be attached to the opening 62A of the frame-shaped part 62 will be described. Figure 12 is a perspective view of the panel 66 in this embodiment. Figure 13 is a perspective view showing the panel 66 shown in Figure 12 with the inner surface material 67 and the stepped screw 69, which is a second locking part, removed. In this embodiment, the panel 66 has four core materials 64A to 64D arranged along the contour line of the opening 62A, which are sandwiched in the thickness direction by the inner surface material 67 and the outer surface material 68. The core materials 64A to 64D and the inner surface material 67 and the outer surface material 68 are integrated by a known method such as an adhesive. Both the inner surface material 67 and the outer surface material 68 are formed as a laminate of a substrate and a decorative plate. Stepped screws 69, which are second locking parts, are erected on the outer circumferential surface of the panel 66 formed in this way at two locations corresponding to the positions of the recessed holes 65. Here, the stepped screw 69 is erected on the lower core material 64A such that the entire diameter portion of the stepped screw 69 and the screw head are exposed from the outer surface of the panel 66.

[0052] The thickness of the panel 66 formed in this manner is the same as the thickness of the frame-shaped portion 62. Furthermore, in accordance with the fact that the opening 62A of the frame-shaped portion 62 is formed in a frustum shape where the outer opening surface 62Y is smaller than the inner opening surface 62X, the outer diameters of the inner surface material 67 and the outer surface material 68 are made different, and the panel 66 is also formed in a frustum shape. In this way, the panel 66 that is fitted into the opening 62A of the frame-shaped portion 62 is also formed in a shape that matches the shape of the opening 62A, so the accuracy of fitting the panel 66 to the frame-shaped portion 62 can be improved.

[0053] Next, as shown in Figure 14, the panel 66 is tilted from the side of the inner opening surface 62X, and the screw head and large diameter portion of the stepped screw 69 are inserted into the recessed hole 65 formed in the opening 62A, as indicated by arrow A. After this, as indicated by arrow B, the panel 66 is mounted by fitting it into the opening 62A while standing the panel 66 upright so that the inner surface of the panel 66 is flush with the inner opening surface 62X. By using a stepped screw 69 as the protruding portion, which is the second locking portion, as in the panel 66 of this embodiment, the protrusion height of the stepped screw 69 from the lower outer peripheral surface of the panel 66 can be easily adjusted, and the accuracy of mounting the panel 66 to the opening 62A of the frame-shaped portion 62 can be improved. In this embodiment, a stepped screw 69 is used as the protruding portion, which is the second locking portion, but it is of course possible to use a regular screw. In this case, it is preferable to mark the required height position on the outer peripheral surface of the screw in order to adjust the screw insertion depth into the core material 64A.

[0054] After the panel 66 is attached to the elbow body 61, it is preferable to fix the frame-shaped part 62 and the panel 66 to the upper core material 64B from the outer peripheral surface side of the frame-shaped part 62 using fixing screws 80, as shown in Figure 15. Figure 16 shows the internal structure of the elbow rest 60 with the fixing screws 80 attached. As shown in Figure 16, the panel 66 attached to the opening 62A of the frame-shaped part 62 has the large diameter portion and screw head portion of the stepped screw 69 erected on the lower outer peripheral surface of the panel 66 inserted into the recessed hole 65 formed on the lower inner peripheral surface of the frame-shaped part 62. In addition, fixing is performed by fixing screws 80 on the side opposite to the side where the recessed hole 65 and the stepped screw 69 are located, so that the frame-shaped part 62 and the panel 66 are firmly fixed together. In addition, while it is preferable that the positions of the recessed hole 65, which is the first locking part, and the stepped screw 69, which is the second locking part, and the position into which the fixing screw 80 is screwed are opposite each other, the arrangement is not limited to this positional relationship.

[0055] In this embodiment, the fixing screws 80 will be exposed on the outer surface of the frame-shaped portion 62. However, since the armrest 90 is attached to the upper surface of the frame-shaped portion 62, the appearance will not be spoiled even if the fixing screws 80 are attached to the upper surface of the frame-shaped portion 62. In this way, the armrest 60 shown in Figure 17 can be assembled. The armrest 60 formed in this way can be fixed by inserting the connecting arm 63 of the armrest body 61 into the insertion hole (not shown) formed in the rear bridge frame 41 of the backrest support member 40 and fastening it with screws from the bottom surface of the rear bridge frame 41.

[0056] Although a chair 100 equipped with the armrest 60 according to the present invention has been described in detail above, the armrest 60 of the present invention is not limited to the above embodiments. For example, in the above embodiments, an example is shown in which the armrest 60 is attached to the armrest mounting seat 48 of the backrest support member 40 of the chair 100, but the armrest 60 can be attached to the main body of the chair 100. Examples of the main body of the chair 100 include the seat support (seat frame 32) and the backrest support member 40.

[0057] Furthermore, the armrest 60 according to the present invention is also suitable when retrofitting a panel 66 to a standard armrest body 61 (without a first locking portion) that is pre-attached to the main body of a chair 100. In this case, the armrest body 61 can be removed from the chair 100, and a recessed hole 65, which serves as a recess for the first locking portion, can be cut into the inner circumferential surface of the frame-shaped portion 62 of the armrest body 61 using a milling machine or the like, thereby retrofitting the panel 66 used in this embodiment. Since the armrest body 61 is fitted with an armrest 90 as a cover, even if the fixing screws 80 that secure the armrest body 61 and the panel 66 are attached from the outer circumferential surface of the armrest body 61, the fixing screws 80 can be hidden by attaching the armrest 90 over the fixing screws 80, making it possible to maintain a good appearance for the armrest 60.

[0058] Furthermore, although this embodiment illustrates a configuration in which the first locking portion is disposed on the lower inner circumferential surface of the frame-shaped portion 62, the location of the first locking portion on the inner circumferential surface of the frame-shaped portion 62 is not limited to the lower inner circumferential surface, but may be the upper inner circumferential surface, the front inner circumferential surface, or the rear inner circumferential surface. In particular, when the first locking portion is disposed on the upper inner circumferential surface of the frame-shaped portion 62, the fixing screws 80 that fix the frame-shaped portion 62 and the panel 66 are attached from the lower outer circumferential surface of the frame-shaped portion 62. Therefore, this configuration is particularly advantageous because, under normal usage conditions, the appearance of the armrest 60 can be kept in good condition without the need to attach a cover to conceal the fixing screws 80.In this embodiment, the armrest 60 is illustrated in a configuration in which a recessed hole 65, which serves as the first locking portion, is disposed in the frame-shaped portion 62 of the armrest body 61, and a stepped screw 69, which serves as the second locking portion, is disposed on the outer circumferential surface of the panel 66, but the embodiment is not limited to this configuration. As a variation of this configuration, a recess serving as a first locking portion is provided on the outer circumferential surface of the panel 66, and a protrusion serving as a second locking portion is provided on the inner circumferential surface of the frame-shaped portion 62 of the elbow body 61.

[0059] Furthermore, while the armrest 60 in this embodiment is illustrated using four core materials 64A to 64D, a frame-shaped core material (not shown) can also be used. Also, while the armrest 60 in this embodiment is illustrated using a stepped screw 69 as the second locking portion (protrusion), it is not limited to this configuration. Additionally, the second locking portion (protrusion) can be integrally formed with the frame-shaped core material on its outer surface.

[0060] Furthermore, in addition to the configuration of this embodiment described above, it is also possible to adopt a configuration in which the selectable components described in the specification are omitted. Moreover, it is also possible to adopt a configuration that appropriately combines the modified examples described in the specification with other known configurations. [Explanation of Symbols]

[0061] 10: Leg support 11: Caster, 12: Leg feather 20: Mainframe 21: Bracket, 22: Front bridge frame, 23: Front link, 25: Axle hole, 27: Switching lever, 29: Cylinder part 30: Seat part 31: Seat support member, 32: Seat frame, 33: Front bridge frame, 33A: Bearing section, 34: Bracket, 35: Inner shell, 35A: Strap groove, 36: Cushioning material, 37: Lifting lever, 38: Hole, 39: Screw hole 40: Backrest support member 41: Rear bridge frame, 42: Rear shell mounting section, 43: Flange, 44: Bearing section, 45: Armrest, 47: Bracket, 48: Elbow mounting base 50: Backrest 51: Back shell, 52: Back plate, 52A: Step, 52B: Flange 53: Back frame, 53A: Groove, 53B: Fitting part, 53C: Rear support part 54: Cushioning material, 55: Headrest, 55A: Main body, 55B: Fixing part 56: Back mounting seat, 56A: Groove for flange, 56B: Groove for front side upholstery, 56C: Groove for back side upholstery, 56D: Vertical rib, 56E: Female thread 60: Armrest 61: Elbow body, 62: Frame-shaped part, 62A: Opening, 62X:Inner opening surface, 62Y:Outer opening surface, 63: Connecting arm, 64A-64D: Core material, 65: Recessed hole, 66: Panel, 67: Inner surface material, 68: Outer surface material, 69: Stepped screw 80: Fixing screw 90: Armrest 100: Chair SJ: Backrest rotation axis W: Operating wire WT: ball part

Claims

1. an armrest body attached to the chair body and having a frame-shaped portion; a panel attached to the opening of the frame-shaped portion, At least one first locking portion is disposed on an inner circumferential surface of the opening, The armrest is characterized in that a second locking portion that forms a pair with the first locking portion is arranged on the outer peripheral surface of the panel.

2. The armrest according to claim 1, wherein the first engaging portion is a recess or a protrusion.

3. The armrest according to claim 2, characterized in that the recess is a machined hole, and the protrusion is formed by the thick-diameter portion and head portion of a shoulder screw raised on the inner surface of the opening or the outer surface of the panel.

4. An armrest as described in any one of claims 1 to 3, characterized in that a screw is threaded from the outer surface of the frame-shaped portion to the frame-shaped portion at a position opposite to the arrangement positions of the first locking portion and the second locking portion.

5. the first engaging portion is disposed on one of a lower side, a front side, and a rear side of the inner circumferential surface of the opening, the second engaging portion is disposed on one of a lower side, a front side, and a rear side of the inner circumferential surface of the panel, 5. The armrest according to claim 4, wherein the screws are covered by a cover attached to the outer peripheral surface of the frame-shaped portion.

6. The armrest according to any one of claims 1 to 5, wherein the opening is formed in a truncated cone shape that gradually narrows from the seat side toward the outside.

7. 7. The armrest according to claim 6, wherein the outer diameter of the inner surface material of the panel, which is the surface on the seat side, is different from the outer diameter of the outer surface material of the panel, which is the outer surface.

8. A chair comprising an armrest according to any one of claims 1 to 7.

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