Mounting Structure of Elbow Pad for Chair

Abstract

To provide a fitting structure of an elbow pad in which an armrest body and a pad material are engaged with each other to make them installable without using screws and in which the installation is made to hardly come off.SOLUTION: An armrest is composed of an armrest body 60 and a pad 50 which is installed on the armrest body. In this armrest, a through hole 63 is drilled that opens in one horizontal direction to the armrest body 60 or the pad 50. The through hole is made to have an elastically deformable projection 55 which contracts when the through hole 63 is passed in the other direction and which expands after the through hole 63 is passed, so that coming off of the through hole 63 is prevented. With the projection 55 fitted in the through hole 63, the pad 50 is installed in the armrest body 60 by making the pad 50 slide into the through hole.SELECTED DRAWING: Figure 16

Description

Technical Field

[0001] The present invention relates to an attachment structure for an elbow pad of a chair. More specifically, the present invention relates to an attachment structure for an elbow pad that can be attached simply by fitting the pad onto the upper surface of the elbow rest body.

Background Art

[0002] Conventionally, there have been many elbow rests for chairs in which a pad material is disposed on the portion of the upper surface of the elbow rest of the chair that is touched by the seated person. This pad material is usually attached by screwing or the like (for example, Patent Document 1).

[0003] There is also a method of attaching a pad material that is simply hooked and locked with a claw or the like (for example, Patent Document 2).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, when the pad is attached to the elbow rest body by screwing, at least the thickness corresponding to the length of the fastening portion of the screw is required, so that the thickness of the pad or the elbow rest body inevitably increases. In recent office chairs, emphasis is also placed on design, and there is a tendency to prefer chairs with a simple and neat appearance. Therefore, it is required that the design of the elbow rest also have a thin thickness.

[0006] In addition, in the case of an attachment structure in which the pad is fixed to the armrest main body by hooking it with a claw or the like, if it is a flexible pad material, there is a risk that it will be easily detached by applying a force in the winding direction. That is, the pad of the armrest is the part that the fingers of the seated person touch the most, and there is a possibility that it may be detached due to mischief or the like.

[0007] Therefore, an object of the present invention is to provide an attachment structure for an elbow pad that enables the armrest main body and the pad material to be fitted and attached without using screws and is difficult to come off.

Means for Solving the Problems

[0008] To achieve such an object, the present invention provides, in an elbow rest composed of an armrest main body and a pad placed on its upper surface, a through hole that opens horizontally in either the armrest main body or the pad, and when passing through the through hole, the other one shrinks, and after passing through the through hole, it expands and cannot come out of the through hole, functioning as a slide prevention mechanism. An elastically deformable First side locking claw is provided On the other hand , Either the armrest body or the pad is provided with an engaging recess that is recessed or penetrates in the same direction as the through hole, and the other is provided with a second side locking claw that protrudes in the same direction as the first side locking claw and is fitted into the engaging recess. By sliding the pad in the width direction of the armrest, the first side locking claw elastically deforms and penetrates through the through hole to engage, and the second side locking claw engages with the engaging recess so that the pad is fixed in three axial directions of the front-rear, left-right, and up-down directions with respect to the armrest body in this way.

[0009] Here, First side locking claw has a wedge portion that is obliquely intersecting with the insertion direction into the through hole, a return portion that is locked to the edge of the through hole, and a leg portion having a length that penetrates the through hole, and is preferably an elastically deformable body that can be elastically deformed in a direction orthogonal to the insertion direction into the through hole.

[0010] In addition, the through hole preferably opens in the width direction of the chair, and the pad is preferably slid in the width direction and fitted.

[0011] Also, A front locking claw is formed at the front edge portion of the pad, and a downward engaging recess into which the front locking claw of the pad fits is formed at the front end of the armrest body. The engaging recess restricts the forward movement of the front locking claw of the pad, but is a cavity that allows movement in the width direction at least by the amount of lateral slide for attaching and detaching the pad is preferable.

[0012] Furthermore, it is preferable to provide an elbow rest to which the attachment structure of the elbow pad according to any one of claims 1 to 4 is applied.

Effects of the Invention

[0013] According to the attachment structure of the elbow pad described in claim 1, By sliding the pad in the width direction of the armrest, the first side locking claw elastically deforms and penetrates through the through hole to engage, and the second side locking claw engages with the engaging recess so that the pad is fixed in three axial directions of the front-rear, left-right, and up-down directions with respect to the armrest body since In the width direction (horizontal) of the armrest the fixing of the pad to the elbow rest main body can be completed by a simple operation of just sliding the pad, and Prevent the positioning and floating of the pad in the front-rear and left-right directions it can be done. Moreover, according to the attachment structure of the same elbow pad , right it can be fixed without using staples, so the elbow rest pad material can be formed thinly.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

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Figure 16

Embodiments for Carrying Out the Invention

[0015] 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 with the seated person as the center. "Front or forward" means the front or forward direction for the chair and the seated person sitting on the seat of the chair in each of the armrest, seat, and backrest. "Rear or backward" means the rear or backward direction for the chair and the seated person in the same way. Also, the direction orthogonal to the front-back direction in the horizontal plane is the left-right direction or width direction for the seated person or the chair in each of the armrest, seat, and backrest. Further, in the armrest, seat, and backrest, the inner side is the side facing the vertical plane in the front-back direction passing through the seated person side or the center of the chair, and the outer side is the side away from the seated person or the side away from the vertical plane in the front-back direction passing through the center of the chair. Furthermore, "up" and "down" are the up and down for the chair and the seated person in each of the armrest, seat, and backrest, and are the up and down in the vertical plane.

[0016] Figures 1 to 2 show an embodiment of a chair to which the present invention is applied. As shown in FIGS. 1 and 2, for example, this chair includes legs 1 provided with casters, a main frame 2 supported by the legs 1, a seat 3 and a backrest 4 that are swingably supported with respect to the main frame 2 and interlock with each other, and armrests 5 fixed to both ends of a rear bridge frame 11 by screws or the like.

[0017] In this embodiment of the chair, as a reaction force mechanism, for example, a reaction force mechanism using a spring that compresses the spring to obtain a reaction force when the back frame 6 tilts backward, and when the backrest is tilted backward, the rear side of the seat support member 30 is lifted in conjunction with each other. Thus, a weight-sensitive (or sensing) reaction force applying mechanism that makes the resistance to back rocking proportional to the user's weight (sensitizes it) is used in combination.

[0018] Here, in the case of this embodiment, the main frame 2 is rotatably supported in a horizontal plane by the leg columns of the legs 1 (in other words, gas springs), while the front is rotatably connected to the bearing portion 34 of the front bridge frame 32 that supports the seat frame 31 via a pair of left and right front links 41. At the same time, by connecting the bearing portion 25 of the rear bridge frame 11 to the rear bracket 42 via the backrest rotation shaft 43, the seat 3 and the backrest 4 are swingably supported.

[0019] Further, although not shown in the figure, a reaction force mechanism including, for example, a compression coil spring is built into the main frame 2, and it is provided between a backrest support member 7 swingably supported on the rear end side of the main frame 2 and a link shaft (not shown) on the front end side of the main frame 2 so as to generate a force that tries to push back the backrest 4 in conjunction with the backward tilt of the backrest 4.

[0020] (Backrest) In the case of this embodiment, the backrest 4 is composed of a back frame 6 that forms a front-view rectangular frame with a hollow inside and a mesh stretched fabric 8 that is stretched across the back frame 6 to form a backrest surface, and is swingably mounted on the main frame 2 via a backrest support member 7. In the case of the backrest 4 in this embodiment, the frame for attaching the mesh stretched fabric 8 is the back frame 6.

[0021] In order to ensure the mechanical rigidity as a structure, the back frame 6 is preferably formed of a synthetic resin having rigidity such as reinforced nylon with glass fiber such as PA6-GF (polyamide 6).

[0022] In this embodiment, as shown in FIGS. 3 and 4 for example, the back frame 6 is formed in a shape that is generally convex forward in a side view (that is, a U-shaped), and is curved so as to be generally convex rearward in a plan view, and constitutes a frame with a hollow inside a front-view substantially vertically long rectangle. Here, a lower side portion 20 forming the lower side of the frame is located at a corner that bends forward in the side-view L-shaped back frame 6, and together with the connecting portion 21 of the back frame 6 that protrudes forward from the lower side portion 20, forms a U-shape that surrounds the back frame attachment portion 12 of the backrest support member 7, and is inserted so as to sandwich the back frame attachment portion 12 from three directions: the left and right sides and the back, and is firmly connected to the back frame attachment portion 12.

[0023] Further, a contact surface 17 that protrudes toward the space inside the frame is provided on the rear end side of the lower side portion 20. This contact surface 17 is composed of a curved surface that is curved in the front-rear direction, and presses the mesh stretched fabric 8 that is stretched across the front surface side of the back frame 6 and protrudes it to the rear side.

[0024] Further, on the back attachment seat 10 on the front surface of the lower side portion 20, a flange groove 22 into which the flange 13 of the back frame attachment portion 12 is inserted is formed. In the middle of this flange groove 22, a vertical rib 23 crossing the groove is formed (that is, the flange groove 22 is formed intermittently), and a female screw 24 for screwing the back frame attachment portion 12 is provided on the vertical rib 23. On the other hand, the flange 13 of the back frame attachment portion 12 is formed intermittently in the circumferential direction so that the flange 13 can be inserted into the flange groove 22 without interfering with the vertical rib 23 provided in the flange groove 22. That is, the lower side portion 20 of the back frame 6 also serves as a portion that fits into the back frame attachment portion 12 of the backrest support member 7.

[0025] On the other hand, the backrest support member 7 has a rear bridge frame 11 and an annular back frame attachment portion 12 (a rectangular frame with a void inside). The rear bridge frame 11 is a wing-shaped frame that extends left and right and curves upward, and together with the annular back frame attachment portion 12 at the rear, creates a space under the seat at the rear of the seat 3. This enables the mesh and cushion that constitute the seat structure (not shown) to bend vertically without interference.

[0026] Furthermore, at the center of the rear bridge frame 11, there is a bearing portion 25 for inserting and swingably connecting the backrest rotation shaft 43 of the bracket 42 at the rear end of the main frame 2, and an arm portion 26 for supporting one member of a spring-type backrest reaction force mechanism (not shown) that hangs downward obliquely forward. It is provided so as to constitute a spring-type backrest reaction force mechanism that pushes out one member of the spring-type backrest reaction force mechanism forward when the backrest 4 tilts backward. Also, on the upper surfaces at both ends of the rear bridge frame 11, there are provided mounting portions, that is, brackets 28, for swingably mounting the brackets 33 at the rear of the outer frame 31. Incidentally, on the outer peripheral surface of the backrest frame mounting portion 12, a flange 13 for inserting the backrest frame 6 from the rear is formed so as to surround the backrest frame mounting portion 12 so as to project rearward and toward both left and right sides. In this way, the backrest support member 7 has a rational structure in which the rear bridge frame 11, the bearing portion 25, the arm portion 26, the backrest frame mounting portion 12, the seat frame mounting portion (bracket 28), and the seat portion (a recess capable of being screwed, hereinafter referred to as the elbow mounting seat 29) for mounting the elbow rest 5 are integrated into one.

[0027] Therefore, the flange groove 22 formed in the backrest mounting seat 10 on the front surface of the lower side portion 20 forming the bottom side as the frame body of the backrest frame 6 is fitted to the flange 13 of the backrest frame mounting portion 12 of the backrest support member 7 and screwed, so that the backrest frame 6 and the backrest support member 7 are integrated into a continuous L-shape in side view. The screwing is, for example, by screwing a screw (not shown) from the inside of the annular backrest frame mounting portion 12 toward the outer backrest mounting seat 10 to connect the backrest frame mounting portion 12 and the backrest frame 6 (that is, the backrest mounting seat 10). That is, the U-shaped backrest mounting seat 10 that protrudes forward of the backrest frame 6 without showing the screw on the appearance is connected and integrated with the backrest frame mounting portion 12. As a result, in this embodiment, the backrest support member 7 and the backrest frame 6 are configured with a neat appearance of a continuous L-shape in side view.

[0028] In this embodiment, the attachment of the mesh fabric 8 to the frame body is carried out by providing a locking member 9 serving as a core material at the periphery of the mesh fabric 8, while on the frame body side, a groove (hereinafter referred to as the fabric groove 18) is provided for inserting the edge of the mesh fabric 8 and the locking member 9 in a direction opposite to the tension application direction applied to the mesh fabric 8, preferably in the reverse direction. The mesh fabric 8 and the locking member 9 are inserted into the fabric groove 18 and hooked. Here, as the locking member 9, for example, a flat plate-shaped polypropylene cord (generally called a PP cord) with a thickness of about 1 mm and a rectangular cross-section can be used. This flat plate-shaped PP cord with a rectangular cross-section is relatively rigid in the width direction (longitudinal direction) and exhibits flexibility in the thickness direction (short transverse direction). However, the locking member 9 is not limited to the aforementioned PP cord. In this embodiment, the locking member 9 is arranged and sewn along the periphery of the mesh fabric 8, and is inserted together with the mesh fabric 8 into the fabric groove 18 in a vertical arrangement (that is, with the width direction in which the PP cord exhibits rigidity as the insertion direction into the groove). Incidentally, the mesh fabric 8 is heat set (which means heat-treating the mesh fabric portion whose periphery is fixed by the back frame or the seat frame and forming it by applying a desired tension through heat shrinkage). Thus, a desired tension is applied.

[0029] In the case of the backrest 4, the mesh fabric 8 is fixed to the back frame 6 by providing the fabric groove 18 on the side surfaces and the bottom surface facing the outer sides of the upper side 6a and the side sides 6b of the back frame 6 and inserting it while applying tension to the mesh fabric 8.

[0030] Here, in the case of this embodiment, the stretching groove 18 of the lower side portion 20 forming the bottom side of the frame body is not formed in the back frame 6 itself, but is formed in the back lower mesh mounting member 14 of a separate member, and is provided so as to be attached to the lower side portion 20 of the back frame 6 via the back lower mesh mounting member 14. In the case of this embodiment, as shown in FIG. 6, the back lower mesh mounting member 14 has, for example, a substantially U-shaped cross-sectional shape, and is applied and fixed so as to cover the back surface of the lower side portion 20 under the contact surface 17. On the inner surface of the back lower mesh mounting member 14 facing the back surface of the lower side portion 20, there is provided a stretching groove 15 into which the edge of the mesh stretching ground 8 and the locking member 9 are inserted and fixed after being folded back one or two times. Further, on the front surface of the back lower mesh mounting member 14, that is, the surface facing the back surface of the lower side portion 20, there is provided a hole for screwing in the fastening screw 16 screwed in from the front side of the lower side portion 20. With the mesh stretching ground 8 inserted into the stretching groove 15, the back lower mesh mounting member 14 is connected to and integrated with the back frame 6. Therefore, the lower end portion of the mesh stretching ground 8 stretched on the front surface of the back frame 6 forms a curved surface without corners while being sandwiched between the back surface of the lower side portion 20 and the back surface of the contact surface 17, and near the contact plate surface 17, as shown in FIG. 2, it is applied to the back side of the contact plate surface 17.

[0031] In the case of this embodiment, as shown in FIG. 7, the locking member 9 of the backrest 4 is divided into four parts: a first cord 9a fitted into a region including the upper side 6a of the back frame 6 and the corner portions 6c at both ends thereof, a second cord 9b and a third cord 9c fitted into both sides of the back frame 6, and a fourth cord 9d fitted into the lower side (bottom side) of the back frame. Further, the mesh stretching ground 8 for the backrest is provided with cuts (not shown) along the end faces of the respective cords at the boundary portions of the first to fourth cords 9a to 9d so as to allow folding back for each of the cords 9a to 9d.

[0032] The first code 9a forms a substantially U-shape similar to the contour shape of the back frame 6 which is a frame body including the upper side 6a of the back frame 6 and the corner portions 6c at both ends thereof, and includes a substantially straight portion along the upper side 6a of the back frame 6 and a curved corner portion 9e along the tensioning groove 18 opening on the side surface of the corner portion 6c. This first code 9a is sewn along the edge on the surface of the mesh tensioning 8.

[0033] On the other hand, the second and third codes 9b, 9c are inserted into the tensioning grooves 18 of the substantially straight side edges 6 of the back frame 6. Here, in the case of the backrest 4, there is a risk that the mesh tensioning 8 may be easily torn at the outer edge portion of the side edge 6a which may collide with a relatively hard substance such as the top plate of a surrounding furniture item such as a chair. To prevent this, it is preferable to interpose a material such as an elastomer material that functions as a buffer between the mesh tensioning 8 outside the tensioning groove 18 and the back frame 6 at the outer edge portion of the side edge 6a of the back frame 6.

[0034] Therefore, in the case of this embodiment, for the second and third codes 9b and 9c, a known PP code with an elastomer (for example, refer to Japanese Unexamined Patent Application Publication No. 2020-62350) having an insertion part that functions as a locking member and an elastomer part that functions as a buffer member is adopted. Although illustration is omitted, the insertion part is made of a synthetic resin, such as polypropylene (PP), which has a hardness such that it is easy to push in when inserted into the tensioning groove 18 and does not easily bend so as not to come out of the fitted state. On the other hand, for the elastomer part, it is preferable to use a material, such as an olefin-based thermoplastic elastomer, that functions as a buffer member against the collision of an object from the outside while being interposed between the mesh tensioning 8 and the side 6b of the back frame 6. And since it is preferable in terms of handling that the elastomer material and the locking member are integrated, for example, it is formed as a resin code (that is, a PP code with an elastomer) in which the insertion part and the elastomer part are integrated by two-color extrusion molding. In this case, with the insertion part, which is the locking member, inserted into the groove of the back frame 6, the elastomer part is folded back and arranged so as to be sandwiched between the mesh tensioning and the front surface of the back frame outside the tensioning groove 18. Therefore, the elastomer part will lift up the mesh tensioning. Thus, as shown in FIG. 5, a depression 19 is formed from the edge of the tensioning groove 18, particularly on the side 6a of the back frame 6, toward the front side of the back frame 6, so that it is lower by the amount of the elastomer part than the surrounding surface. This prevents a step from occurring between the surface of the surrounding back frame even when the elastomer part is interposed between the mesh tensioning and the back frame, reducing the sense of discomfort both in terms of design and when touched by hand.

[0035] Here, according to the second and third cords 9b and 9c each consisting of a locking member with an elastomer part, after sewing to the surface of the mesh backing 8 and then folding back twice (rotating 360°), since the elastomer part is disposed inside on the back side of the mesh backing, the elastomer part will be inserted into the groove 18 for the backing. Therefore, the second and third cords 9b and 9c are attached by sewing to the mesh backing 8 with the insertion part (the part of the locking member) disposed outside and the elastomer part disposed inside along the peripheral edge of the back surface of the mesh backing 8. Then, it is folded back once (rotated 180°) at the boundary between the insertion part (the part of the locking member) and the elastomer part, and the insertion part (the part of the locking member) and the mesh backing 8 are inserted into the groove 18 for the backing.

[0036] Furthermore, in the case of this embodiment, for example, as shown in FIG. 6, the fourth cord is attached via a lower-back mesh attachment member 14 fixed to the bottom edge 20 of the back frame 6. In the case of this embodiment, the central part of the lower-back mesh attachment member 14 is gently curved backward when viewed from below. Therefore, the groove 15 for the backing formed on the inner surface of the lower-back mesh attachment member 14 and the fourth cord 9d inserted therein are also gently curved backward as a whole. Therefore, similar to the first cord 9a, the fourth cord 9d is sewn to the surface of the mesh backing 8, folded back twice to form a curvature in the same direction as the groove 15 for the backing of the lower-back mesh attachment member 14, and then inserted. Then, for example, with the mesh backing and the PP cord 9 inserted, the lower-back mesh attachment member 14 is placed on the back side of the back attachment seat 10 of the back frame 6 and fixed to the back frame 6 by screwing from the front.

[0037] According to the attachment structure of the meshed ground configured as described above, the first cord 9a sewn on the surface of the meshed ground 8 is folded back to the back side, and the meshed ground 8 is wound around the sewing position (i.e., the attachment position) 44 of the first cord 9a, and the tip side part (in other words, the edge side of the ground) 8e of the meshed ground 8 is folded back (see FIGS. 11(A) and (B)). Then, by folding back to the back side once again, the meshed ground 8 is wound around the tip of the first cord 9a (in other words, the edge side of the meshed ground 8), and the meshed ground 8 inside the sewing position 44 is folded back (see FIG. 11(C)). At this time, the edge side part 8e of the meshed ground 8 is caught in the folded part, and a part of the first cord 9a, that is, the part 45 inside the sewing position 44, is exposed and becomes bare. Therefore, it becomes easy to insert the locking member, the first cord 9a, and the meshed ground 8 into the ground groove 18, and the edge of the meshed ground 8 does not protrude from the ground groove 18, eliminating the need to push the edge of the meshed ground 8 into the groove 18. The same applies to the fourth cord 9d.

[0038] Here, except for exceptional locking members such as the locking members with elastomer parts (i.e., the second and third cords 9b, 9c), in the case of the locking member 9, particularly the first cord 9a having the corner portion 9e, it is important that the attachment of the locking member 9 to the mesh ground 8 is on the surface side of the mesh ground 8. When the locking member 9 is attached to the back side of the mesh ground 8 by sewing or the like, in the case of a locking member such as the first cord 9a including the corner portion 9e, it will not take the shape along the locking member by being wrapped by the mesh ground. That is, a locking member such as the corner portion 9e cannot rotate 360° in the first place and cannot be fitted into the ground groove. Also, even for a linear locking member, even if the locking member is rotated 360° while folding the mesh ground, the entire locking member will be wrapped by the mesh ground 8, so that only the mesh ground 8 will become double and the thickness will increase, and it is impossible to obtain the ease of fitting into the ground groove such as the terminal structure where a part of the locking member shown in this embodiment is exposed and functions as a guide. Furthermore, since the entire locking member is wrapped by the mesh ground 8, there is a problem that a protruding portion, for example, an ear portion 39 cannot be formed at the edge of the locking member.

[0039] Furthermore, the attachment position of the retaining member 9 and the mesh fabric 8, i.e., the sewing position 44 in the case of sewing, is not limited to the center position in the width direction. It can be implemented even closer to the edge or at a position away from the edge, and effects such as facilitating the insertion of the mesh fabric 8 into the fabric groove 18 are not lost. Further, when the sewing position 44 of the first cord 9a to the mesh fabric 8 is set approximately at the center position in the width direction of the cord 9a, it will be folded back by a distance corresponding to the width of one cord in two folds. Therefore, the end of the first cord 9a, i.e., the end of the corner portion 9e, will be arranged at the same position as when the second and third cords (PP cords with elastomers) 9b and 9c are folded back once. For this reason, in the folded state, the corner portions 9e at both ends of the first cord 9a and the ends of the second and third cords 9b and 9c will be at the same position, that is, there will be no difference in the cord position in the insertion direction of the fabric groove. Also, the corner portions 9e at both ends of the first cord 9a forming an inward curve will return to their original curved state by rotating 360°. Therefore, they will have a shape along the curved shape of the fabric groove 18 of the back frame 6 (the corner portion 9c between the upper side 9a and the side 9b) and can be inserted into the fabric groove 18 of the back frame 6. For this reason, there is no risk of the mesh fabric 8 coming off at the corner portion 9e.

[0040] (Seat structure) In the case of this embodiment, the seat 3 is composed of, for example, as shown in FIGS. 8 and 9, a mesh fabric 37 forming a seat surface, an annular inner shell 35 for attaching the mesh fabric 37, and a seat support member 30 including an outer shell 31. It is mounted on the main frame 2 via the seat support member 30 so as to be swingable by the front link 41 and the backrest support member 7 of the main frame 2. In the case of the seat 3 in this embodiment, the inner shell 35 and the outer shell 31 as the frame for attaching the mesh fabric 37 are assembled by placing the inner shell 35 on the outer shell 31 and screwing from below.

[0041] The seat support member 30 of this embodiment is not limited to a specific structure and shape. For example, it has an annular outer shell (a rectangular frame with a cavity inside) 31, a front bridge frame 32 that supports the front of the outer shell 31, and a bracket 33 for connecting the seat support member 7 at a position slightly closer to the rear than the middle of the outer shell 31. The bearing portion 34 at the central part of the front bridge frame 32 is swingably connected to and supported by the front link 41 of the main frame 2. On the other hand, the bracket 33 on the rear side of the outer shell 31 is connected to the bracket 28 of the seat support member 7 by a rotating shaft (not shown) and is swingably supported. Therefore, the seat 3 will move in conjunction with the movement of the backrest 4.

[0042] The front bridge frame 32 is a wing-shaped frame that extends horizontally and curves upward. In combination with the rear bridge frame 11 of the seat support member 7 and the back frame mounting portion 12, it creates a space under the seat (see FIGS. 1, 2, and 8). This enables the mesh fabric 37 to bend vertically without interfering with the main frame 2. Also, it has the effect of making it look lighter in terms of design.

[0043] Here, the mounting position of the bracket 33 on the rear side of the outer shell 31 with respect to the rear bridge frame 11 is provided in front of the backrest rotation axis 43 of the rear bridge frame 11, and is in a position where the seat support member 30 (that is, the seat 3) can be lifted when the backrest support member 7 tilts backward. That is, as the backrest 4 tilts backward, the seat 3 is lifted, and a part of the weight of the seated person acts as a resistance against the backward movement of the backrest 4 (the locking resistance is weight-sensitive). It is provided to constitute a weight-sensing reaction force applying mechanism (or a weight-sensitive reaction force applying mechanism).

[0044] In the seat 3 of the present embodiment, the attachment of the mesh tensioning member 37 to the inner shell 35 is performed, for example, in the same manner as in the case of the backrest 4 described above, by fitting the mesh tensioning member 37 provided with a locking member 38 such as a PP cord along the periphery into the tensioning groove 36 formed on the outer peripheral side surface of the inner shell 35 together with the locking member 38. In the case of the seat 3, a tensioning groove 36 that encircles the outer sides of the front side 35a, the left and right side edges 35b, the rear side 35d of the inner shell 35, and the corner portions 35c therebetween is provided, and it is fixed by inserting while applying tension to the mesh tensioning member 37.

[0045] Further, as shown in FIG. 10, the locking member 38 is divided into a first cord 38a that is fitted into a region including the front side 35a of the inner shell 35 and the corner portions 35c at both ends thereof, a second cord 38b and a third cord 38c that are fitted into the left and right side edges 35b of the inner shell 35, and a fourth cord 38d that is fitted into a region including the rear side 35d of the inner shell 35 and the corner portions 35c at both ends thereof.

[0046] The first cord 38a forms a substantially U-shape similar to the contour shape including the front side 35a of the inner shell 35 and the corner portions 35c at both ends, and is sewn along the edge on the surface of the mesh tensioning member 37. On the other hand, the second and third cords 38b, 38c are generally linear and are sewn along the edge on the surface of the mesh tensioning member 37. Further, the fourth cord forms a substantially U-shape similar to the contour shape including the rear side 35d of the inner shell 35 and the corner portions 35c at both ends, and is sewn along the edge on the surface of the mesh tensioning member 37. In the case of the present embodiment, corner portions 38e are included at both ends of the first cord 38a and the fourth cord 38d, but it is not particularly limited thereto. For example, corner portions 38e may be included on the sides of the second and third cords 38b, 38c, or in some cases, only the corner portions 38e may be made independent as locking members. Also, in some cases, corner portions 38e may be included at each end of each of the first cord 38a to the fourth cord 38d.

[0047] As shown in Fig. 12, the conventional method of attaching the locking member (PP cord) to the backing involves sewing it along the edge of the backing on the back surface of the mesh backing 37. Then, the mesh backing 37 is folded back once so as to wrap the locking member 38, and then inserted into the backing groove 36 (see Fig. 12(B)). However, according to this method, at the mesh backing portion 37e beyond the sewing location (i.e., the attachment location) 44, the mesh backing may lift away from the locking member 38, making it difficult to properly fit into the backing groove 36. In some cases, the edge 37e on the tip side beyond the stitching location 44 of the mesh backing 37 may be inserted into the groove 36 in a folded-back state, or may not be inserted at all. Further, when the portion lifted away from the locking member 38 protrudes from the backing groove 36, it is necessary to use a jig or the like to tuck it into the backing groove, which increases the number of working steps.

[0048] Furthermore, in the case of a curved locking member, i.e., the corner (edge) portion 38e, when the locking member is rotated once, the curve shape of the corner portion 38e faces outward (the direction of the curve is reversed) and cannot enter the backing groove 36, so there is a problem that the locking member 38 cannot be used. For this reason, at the corner portion 38e, only the mesh backing 37 remains, so it is necessary to use a jig to push the mesh backing at the corner portion into the backing groove. For this reason, there is a problem that it is necessary to perform the labor and working steps of pushing the mesh backing at the corner portion into the backing groove in order to improve the appearance. Moreover, since only the mesh backing is pushed in without the presence of the locking member, there is a problem that the mesh backing is likely to come off.

[0049] Therefore, in the present embodiment, the locking member 38 is sewn along the periphery on the surface of the mesh backing 37. First, the locking member 38 is folded back once to the back surface side of the mesh backing 37, and then folded back once again so as to wrap the locking member 38 with the mesh backing 37 (conveniently, folded back twice), and then inserted into the backing groove 36.

[0050] The above-described first to fourth codes 38a, 38b, 38c, and 38d are sewn onto the surface side of the mesh ground 37 by sewing. Then, cuts parallel to the ends of the resin codes are made in the ground located at the boundary portions of the first to fourth codes 38a, 38b, 38c, and 38d, and are provided to allow folding back for each code.

[0051] In the case of the seat of the present embodiment, for each of the cords 38a, 38b, 38c, and 38d, by folding it twice (rotating the cord 360°) on the back side of the meshed fabric, a part of each of the cords 38a, 38b, 38c, and 38d is wrapped by the meshed fabric 37, and the tip-side part 45 of each of the cords 38a, 38b, 38c, and 38d is exposed from the sewing position 44 to the meshed fabric 37 and is inserted into the fabric groove 36 while remaining exposed. That is, as shown in FIG. 11, while the cord 38 sewn on the front side of the meshed fabric 37 and the meshed fabric 37 rotate twice, the meshed fabric 37 is folded back starting from the sewing position 44 and further wound around the edge of the base-end side part 46 of the cord 38. Therefore, the tip-side part 45 of the cord 38 is inserted into the fabric groove 36 in an exposed state. Therefore, at the edge of the fabric groove 36, the folded meshed fabric 37 is formed so as to cover the base-end side part 46 outside the sewing position 44 of the cord 38 and the edge 37e of the meshed fabric, so that the shape of the edge of the meshed fabric 37 is adjusted. Moreover, since the edge 37e of the meshed fabric 37 is not exposed on the tip side in the insertion direction of the meshed fabric 37, the meshed fabric 37 does not protrude from the fabric groove 36, the process of pushing it in becomes unnecessary, one process can be reduced, and the appearance also improves. Also, since a part of the cord, that is, the tip-side part 45, is exposed, it can be inserted into the fabric groove 36 prior to the cord 38, and the operation of inserting the edge 37e of the meshed fabric 37 into the fabric groove 36 becomes easier. Also, in the corner part 38e which is a locking member curved inward (toward the center of the fabric), since the cord 38 and the meshed fabric 37 are rotated 360°, the corner part 38e returns to its original curved state, so that it has a shape along the curved shape of the fabric groove 36 of the inner shell 35 (the corner part 35c between the front side 35a and the side 35b) and can be inserted into the fabric groove 36 of the inner shell 35. For this reason, the risk of the meshed fabric 37 coming off at the corner part 38e is eliminated. Also, the same applies to the corner part 38e of the fourth cord 38d.

[0052] Furthermore, since the external force / load applied to the seat 3 is greater than that applied to the backrest 4, in order to ensure that the respective cords 38a, 38b, 38c, and 38d for the seat are fully protected against the mesh fabric coming off, it is preferable that ear portions 39 for screwing are formed. The position of this ear portion 39 is arbitrary and may be provided at any location on any of the cords, but it is particularly preferable that the ear portions 39 are formed at both ends of the first cord 38a and the fourth cord 38d, that is, at the ends of the corner portion 38e. The ear portion 39 is provided at the inner edge when sewing the respective cords 38a, 38b, 38c, and 38d to the mesh fabric 37. Each of the cords 38a, 38b, 38c, and 38d is sewn to the surface of the mesh fabric, folded back twice toward the back side, and then inserted into the fabric groove 36, so that the ear portion 39 protrudes toward the inside of the frame body. Therefore, as shown in Fig. 11(D), the ear portion 39 is fixed to the inner shell 35 by, for example, screwing a fastening screw 40 from the lower surface side of the inner shell 35 in a state where it is inserted into the fabric groove 36. Since this ear portion 39 is arranged in a direction (inward) away from the edge of the mesh fabric 37 when sewing the respective cords 38a, 38b, 38c, and 38d along the edge of the mesh fabric 37 by machine sewing, it does not interfere during machine sewing and does not reduce work efficiency. In addition, in this embodiment, the screwing of the ear portion 39 of each cord is for safety (to increase the load-bearing capacity of the seat) and may not be provided in some cases. Also, the ear portion 39 is not limited to the locking member 38 for the seat and may be provided on the locking member 9 for the backrest in some cases. Further, the fixing method of the ear portion 39 to the inner shell 35 is not limited to the above-described screwing and may be tacking or other fixing means.

[0053] In addition, in the case of this embodiment, the attachment method of the locking members (for example, PP cords) 9, 38 to the mesh fabrics 8, 37 is not limited to a specific method as long as they can be attached so as to be reversible. Other methods such as adhesion and welding are possible in addition to sewing, but sewing is preferable.

[0054] In the case of this embodiment, as shown in FIGS. 1 and 16 for example, the armrest 5 is composed of an armrest body 60 made of aluminum die-cast and a pad 50 made of synthetic resin attached to the upper surface thereof. Of course, the materials of the armrest body 60 and the pad 50 are not particularly limited to those described above and are to be appropriately selected. In addition, in this embodiment, an example of applying to a fixed armrest in which the position, height, orientation, etc. of the armrest are fixed with respect to the chair will be mainly described. However, it is not particularly limited to this, and it goes without saying that it may be applied to a movable armrest in which the position, height, orientation, etc. of the armrest are variable.

[0055] When the pad 50 is attached to the armrest body 60 by screwing, since at least the thickness corresponding to the length of the fastening portion of the screw is required, there is a problem that the pad 50 or the armrest body 60 inevitably becomes thick and looks clumsy in terms of design. In recent office chairs, design is also emphasized, and chairs with a simple and neat appearance tend to be preferred. Therefore, the design of the armrest is also required to have a thin thickness.

[0056] On the other hand, in the case of an attachment structure in which the pad 50 is fixed to the armrest body 60 by hooking with a claw or the like, if it is a flexible pad material, there is a risk that it will easily come off by applying a force in the winding direction. That is, the pad 50 of the armrest is the part that the fingers of the seated person touch most often, and there is a possibility that it will come off due to mischief or the like. In addition, there is a risk that it will easily come off when a strong force acts. For example, when trying to lift the body from the chair while grasping near the front end of the armrest or while pushing it down, the entire weight of the seated person acts as a force (sliding force) moving the pad forward, so there is a risk that the pad will shift or fall off.

[0057] Therefore, in the case of this embodiment, while achieving attachment to the armrest main body 60 by sliding the pad 50 horizontally, the pad material 50 and the armrest main body 60 are fitted and attached without using screws. Of course, although not shown, the pad 50 may be slid in the front-rear direction to achieve attachment to the armrest main body 60.

[0058] The armrest main body 60 of this embodiment, as shown in FIG. 13 for example, has a frame shape with a hollow inside in a trapezoidal shape in side view having an upper side 70, a front side 71, a rear side 72, and a bottom side 73, and is screwed to the elbow mounting seat 29 via the mounting arm portion 74 and supported by the backrest support member 7. Further, in the armrest main body 60, a recess 75 is formed in which a part of the upper surface portion 66 and the inner side wall portion (hereinafter referred to as the inner wall portion 67) from the upper side 70 to the front side 71 is removed, and the pad 50 is housed in this recess 75 to form the surface (i.e., the top surface) of the armrest. In the case of this embodiment, the armrest main body 60 is formed by aluminum die casting, but the material is not particularly limited.

[0059] In the recess 75, in the case of this embodiment, a locking rib 61 for supporting the resin pad 50 in the width direction of the chair is formed between the outer wall portion (hereinafter referred to as the outer wall portion 68) of the upper side 70 of the armrest main body 60. Further, between the outer wall portion 68 of the upper side 70 of the armrest main body 60 and the locking rib 61, at least one supporting rib 62 for vertically supporting the middle part of the upper portion 51 of the pad 50 is formed so that no dent occurs when an external force is applied to the pad 50. This supporting rib 62 may not be provided in some cases. Needless to say, these ribs 61 and 62 also serve the original role of ribs for reinforcing the reduction in rigidity due to the loss of the inner wall portion 67 and the upper surface portion 66 of the armrest main body 60.

[0060] The locking rib 61, for example, has a space for supporting the inner side wall portion (hereinafter referred to as the inner wall portion 53) of the resin pad 50 at the bottom 69 of the upper side 70 of the armrest main body by the locking rib 61 InsideIt is provided on the side (i.e., the seated person side). Specifically, for example, a locking rib 61 is provided at a position offset outward by an amount corresponding to the thickness of the inner wall portion 53 of the resin pad 50 from the inner end of the bottom portion 69 of the armrest body 60. Of course, the position of the locking rib 61 is not particularly limited to the above, and can be changed as appropriate, but it is preferable to secure at least a space sufficient to support the inner wall portion 53 of the resin pad 50. On the other hand, the supporting rib 62 is provided at a position further Outside offset to the side than the locking rib 61. In the case of the illustrated supporting rib 62, it is formed thicker than the locking rib 61, but it is not particularly limited to this, and it goes without saying that it can be made to have an arbitrary thickness or number. Further, these ribs 61 and 62 are formed lower than the original top surface height of the upper side 70 of the armrest body 60 so that the pad 50 fits into the recess 75 of the upper side 70 of the armrest body 60. Specifically, for example, it is formed at a height lower by the thickness of the upper portion 51 of the pad 50 or a slightly thinner thickness, and when the pad 50 is mounted so as to cover it, the resin pad 50 is provided so as to fit flush with or slightly higher than the top surface of the upper side 70 of the armrest body 60.

[0061] As a structure for attaching the pad 50 to the armrest body 60, it utilizes the fitting of unevenness in three orthogonal axial directions. For example, a front locking claw 57 is provided at the tip edge portion of the pad 50, a first side locking claw 55 is formed on the inner surface side of the inner wall portion 53, and a second side locking claw 56 is formed on the outer surface side of the outer side wall portion (hereinafter referred to as the outer wall portion 52). On the other hand, in the armrest body 60, a through hole 63 through which a first side locking claw 55 protruding outward from the inner wall portion 53 of the pad 50 penetrates the locking rib 61, a locking recess 64 into which a second side locking claw 56 protruding outward from the outer wall portion 52 of the pad 50 is fitted in the outer wall portion 68, and a downward engaging recess 65 into which the front locking claw 57 of the pad 50 is fitted is formed at the front end of the recess 75 leading to the front side 71. The engaging recess 65 restricts the forward movement of the front locking claw 57 of the pad 50, but is a cavity that allows movement in the width direction at least by the amount of lateral slide for attaching and detaching the pad 50.

[0062] The first lateral locking claw 55 is formed, for example, integrally with the pad 50 (therefore, formed of resin), so as to project from the inner surface of the inner wall portion 53 of the pad 50 toward the outer wall surface 52 on the opposite side. This first lateral locking claw 55 is an elastically deformable protrusion having a return that narrows when passing through the through hole 63 and widens after passing through the through hole 63 and cannot come out of the through hole 63. For example, it consists of a wedge portion 55c that is obliquely intersecting with respect to the insertion direction into the through hole 63, a return portion 55b that is locked to the edge of the through hole 63 of the locking rib 61, and a leg portion 55a having a length that penetrates the locking rib 61, and is composed of an elastically deformable body that can be elastically deformed in a direction orthogonal to the insertion direction into the through hole 63 (see Fig. 15). That is, the first lateral locking claw 55 is a so-called house-shaped or mushroom-shaped elastic protrusion that functions to pass the through hole 63 while narrowing the return portion 55b that expands in a wedge shape, and after passing through the through hole 63, the return portion expands and gets caught.

[0063] In the example shown in the figure, the first lateral locking claws 55 are provided at five locations on the inner surface of the inner wall portion 53 of the pad 50 at substantially regular intervals. Note that the number of the first lateral locking claws 55 is not limited to the example shown in the figure, and is appropriately set to an appropriate number in consideration of, for example, ensuring the engagement force between the pad 50 and the armrest body 60.

[0064] Also, a rib 58 that slightly projects in the width direction of the armrest is formed at a position substantially in the middle between adjacent first lateral locking claws 55 and first lateral locking claws 55. This rib 58 consists of, for example, a linear protrusion extending in a direction perpendicular to the upper portion 51 of the pad 50. That is, by alternately forming the rib 58 and the first lateral locking claws 55, a reaction force is applied to the first lateral locking claws 55 that penetrate the through hole 63 of the locking rib 61 to absorb play. The inner side wall portion 53 of the pad 50 that abuts against the rib 58 is pulled by the fitting of the first lateral locking claws 55 between the ribs 58 and the through hole 63, so it receives a force to bend slightly, and a load is constantly applied so that no play occurs between the first lateral locking claws 55 and the through hole 63.

[0065] The forming direction of the first side locking claw 55 is not particularly limited, but it depends on the direction of the through hole 63 formed in the locking rib 61 of the armrest main body 60. For example, when a horizontally long rectangular through hole 63 is provided in the locking rib 61 along the bottom 69 of the armrest main body 60, in the case of the first side locking claw 55 in the illustrated example, it is formed to protrude from the inner wall portion 53 to the outer wall portion 52 of the pad 50 so that the elastic deformation direction is set in the horizontal direction. Note that the forming directions of the plurality of first side locking claws 55 may all be the same, or may be adjusted so that the plurality of first side locking claws 55 can firmly respond as a whole to an external force, or may be adjusted in consideration of the direction of the external force applied by the part of the pad 50 being assumed.

[0066] The engaging recess 65 formed on the front side of the armrest main body 60 has a clearance in the width direction so that the pad 50 can slide in the width direction while the front locking claw 57 at the tip of the pad 50 is fitted. Further, when the front locking claw 57 is inserted into the engaging recess 65, an inclined surface for generating a wedge effect is provided at the tip in order to generate a force that biases the pad 50 rearward between the pad 50 and the armrest main body 60. Therefore, at the same time as the front locking claw 57 is inserted into the engaging recess 65, the front surface side of the front locking claw 57 is in close contact with the front inner surface of the engaging recess 65 without a gap in the front-rear direction, a force that biases the pad 50 rearward is applied, and the pad 50 is positioned so as not to shift forward.

[0067] The pad 50 has the second lateral locking claw 56 inserted and engaged in the engaging recess 64, and the first lateral locking claw 55 inserted and engaged in the through hole 63. At the same time, the first lateral locking claw 55 penetrates through the through hole 63 while elastically deforming and then expands again, thereby functioning as a retaining mechanism in the width direction, i.e., a lateral slide prevention mechanism. On the other hand, the rear edge 54 of the pad 50 abuts against the wall surface of the recess 75 of the armrest body 60 (the end face of the upper side 70 exposed by the recess 75), while the front edge 59 abuts against the wall surface of the engaging recess 65 (the end face of the front side 71 exposed by the engaging recess 65), and the tip-side locking claw 57 fits into the engaging recess 65 and functions as a retaining means, so that the pad 50 is fixed immovably in the front-rear direction. That is, the pad 50 is engaged in a direction orthogonal to the sliding direction of the pad 50 by the fitting of the engaging recess 64 and the second lateral locking claw 56.

[0068] In addition, the engaging recess 64 on the outer wall portion 68 of the armrest body 60 made of aluminum die-casting is a depression that does not penetrate the outer wall portion 68 so as not to impair the appearance, and thus is formed by post-processing such as cutting or grinding. Further, since the through hole 63 of the locking rib 61 is a through hole, for example, a rectangular hole, it is formed simultaneously during die-casting.

[0069] The second lateral locking claw 56 is a so-called protrusion that is inserted into the engaging recess 64, and by fitting into the engaging recess 64, the armrest body 60 and the pad 50 are engaged in a direction orthogonal to the sliding direction of the pad 50. That is, the second lateral locking claw 56 is not limited to a specific form such as the illustrated protrusion as long as it serves to position the pad 50 in the front-rear direction and prevent it from floating.

[0070] In the case of the present embodiment, the second lateral locking claw 56 and the engaging recess 64 are arranged substantially on the extension line of the position where the first lateral locking claw 55 and the through hole 63 are engaged, but it is not particularly limited thereto, and they may be arranged at an arbitrary position, for example, shifted in the front-rear direction from the engaging position of the first lateral locking claw 55 and the through hole 63.

[0071] In the example shown in the figure, the first lateral locking claw 55 and the second lateral locking claw 56 are provided on the side of the pad 50, and the through hole 63 and the engaging recess 64 are provided on the side of the armrest body 60. However, the arrangement of the first lateral locking claw 55, the through hole 63, the second lateral locking claw 56, and the engaging recess 64 is not limited to the example shown in the figure. Additionally, the arrangement where the second lateral locking claw 56 is provided on the side where the first lateral locking claw 55 is provided as in the example shown in the figure is not limited either. Specifically, for example, as an example only, the first lateral locking claw 55 may be provided on the pad 50 and the second lateral locking claw 56 may be provided on the armrest body 60.

[0072] In this embodiment, while the first lateral locking claw 55 and the second lateral locking claw 56 are provided on the pad 50, the through hole 63 and the engaging recess 64 are provided on the armrest body 60, and it has an attachment structure that slides in the width direction of the armrest for attachment. However, it is not limited to this. The first and second lateral locking claws 55, 56, the through hole 63, and the engaging recess 64 may be provided on at least one of the armrest body 60 and the pad 50. For example, although not shown, a second lateral locking claw 56 that protrudes inwardly may be provided on the armrest body 60, and an engaging recess in the form of a recess or a through hole may be provided on the outer wall portion 52 of the pad 50. Of course, the first lateral locking claw 55 may be provided on the armrest body 60 and the through hole 63 may be provided on the pad 50.

[0073] In addition, the attachment structure of the pad 50 to the armrest body 60 in this embodiment is detachably provided by the first lateral locking claw 55 that elastically deforms and engages with the through hole 63 of the armrest body 60. However, it is not limited to this, and a non-detachable connection structure may also be used.

[0074] The first lateral locking claw 55 fitted into the through hole 63 does not easily come off from the through hole 63 of the armrest body 60, but will come off when pulled with an appropriate force. That is, it is pulled out from the through hole 63 while narrowing the return portion that spreads out in the shape of a wedge of the first lateral locking claw 55.

[0075] With the first side locking claw 55 and the through hole 63, the binding force between the pad 50 and the armrest body 60 is appropriately ensured, and the pad 50 can be removed from the armrest body 60 as needed, such as when replacing the pad. That is, a detachable and yet difficult-to-remove engagement / connection is realized.

[0076] According to the pad mounting structure of the armrest configured as described above, while fitting the outer wall portion 52 of the pad 50 between the outer wall portion 68 of the armrest body 60 and the support rib 62, and positioning the inner wall portion 53 of the pad 50 inside the locking rib 61, covering the pad 50 over the recess 75 of the armrest body 60, and sliding the pad 50 in the width direction from the inside to the outside of the armrest 5 while the front locking claw 57 on the front end side of the pad 50 slides inside the engaging recess 65, the first side locking claw 55 of the pad 50 elastically deforms, penetrates the through hole 63 of the armrest body 60 and engages therewith, and the second side locking claw 56 engages with the engaging recess 64 of the armrest body 60 and is fixed in the three axial directions of the front-rear, left-right, and up-down directions.

[0077] During the use of the product, a forward force is likely to act on the armrest 5. However, since the pad 50 does not move forward, there is no risk of coming off from the armrest body 60. Also, since it is a non-screw fixing, the pad 50 and the armrest body 60 can be formed thinly.

[0078] Therefore, it is possible to prevent the first side locking claw 55 from being displaced or deformed and the engagement with the through hole 63 from being unexpectedly disengaged, and it is possible to improve the usefulness and reliability of the engagement structure, and it is also possible to improve the safety and comfort of use of the backrest and chair to which the engagement structure is applied.

[0079] Also, in the illustrated embodiment, the pad 50 is attached to the armrest main body 60 by sliding it in the width direction from the inside to the outside of the armrest 5. However, it is not particularly limited to this. In some cases, it may be attached to the armrest main body 60 by sliding it in the width direction from the outside to the inside of the armrest 5. In this case, it goes without saying that the arrangement of the locking rib 61, the supporting rib 62, and the remaining outer wall portion 68, and the positional relationship between the first side locking claws 55 and the second side locking claws 56 of the pad are symmetric with respect to the axis in the front-rear direction as in the case of the illustrated embodiment.

[0080] Therefore, to attach the pad 50 to the armrest main body 60, while fitting the front locking claw 57 at the tip edge portion of the pad 50 into the engaging recess 65 on the front side 71 of the armrest main body 60, the outer wall portion 52 of the pad 50 is received between the outer wall portion 68 and the supporting rib 62 of the armrest main body 60, and the pad 50 is placed over the recess 75 on the upper side 70 of the armrest main body 60 so that the first side locking claw 55 on the inner wall portion 53 is aligned with the through hole 63 of the locking rib 61, and then slid laterally. As a result, the first side locking claw 55 on the inner wall portion 53 of the pad 50 and the second side locking claw 56 on the outer wall portion 52 are fitted into the through hole 63 of the locking rib 61 and the engaging recess 64 on the outer wall portion 68 of the armrest main body 60. Thereby, the pad 50 is locked in the three axial directions of front-rear, left-right, and up-down, and is fixed to the armrest main body 60.

[0081] Incidentally, the form of the attachment structure of the mesh stretching ground described above is an example of a preferred form of the present invention, but it is not limited thereto, and various modifications can be made without departing from the gist of the present invention. For example, in the above-described embodiment, the locking member at the upper side portion of the backrest or the locking members at the front end and the rear end portions of the seat were described by giving an example of a locking member in which a straight portion and a curved corner portion are continuously formed, but it is not particularly limited thereto. For example, in the above-described embodiment, corner portions are included at both ends of the first cord, but it is not particularly limited thereto, and it may be included only at one end or on the side of other cords, for example, the second and third cords. In some cases, only the corner portions 9e, 38e may be made independent as the locking members. In any case, the locking member of the corner portion is provided on the surface of the stretching ground and forms the same orientation as before folding by folding back twice, so that it fits into the groove for the stretching ground. Also, an example using a PP cord with an elastomer was described for the side of the backrest, but it is not particularly limited thereto, and for example, a PP cord without an elastomer portion may be used. In this case, it is preferable to sew the locking member on the surface side of the mesh stretching ground and fold it back twice and insert it into the groove. Also, in this case, the corner portion 9c may be included at one end of the first cord 9a and the ends of the second or third cords 9b, 9c on the other end side. Incidentally, in the case of this embodiment, corner portions 38e are included at both ends of the first cord 38a and the fourth cord 38d, but it is not particularly limited thereto, and for example, the corner portion 38e may be included on the side of the second and third cords 38b, 38c, or in some cases, only the corner portion 38e may be made independent as the locking member. Also, in some cases, the corner portion 38e may be included at each one end of the first cord 38a to the fourth cord 38d.

[0082] In addition, the configuration of the chair to which the present invention can be applied, particularly, the specific shape and mode of each component member such as the inner shell 35 or the back frame 6 constituting the frame over which the mesh stretching ground is stretched, are not limited to those in the above-described embodiment, and are appropriately selected in consideration of the use and design of the chair.

[0083] Furthermore, in this embodiment, an example using a stretch fabric of a mesh material rich in elasticity is described, but the present invention is not particularly limited thereto. For example, in a full wrap (a method of wrapping the inner shell and the cushion entirely with an upper stretch fabric), it may be applied to an embodiment that covers the back frame 6 or the seat inner shell 35.

[0084] Furthermore, the armrest 5 is fixed to the arm mounting seats 29 at both ends of the rear bridge frame 11 by screws or the like as necessary. Therefore, when the armrest 5 is not required, the arm mounting seats 29 are covered with a cover, that is, a cover configured by a surface that is continuously connected to the outer shell surface of the rear bridge frame 11.

[0085] Furthermore, in the above-described embodiment, an example of applying the present invention to a synchro locking mechanism that combines a weight-sensitive reaction force applying mechanism that generates a force to push back the backrest by raising the seat in conjunction with the backward tilt of the backrest of the chair and a reaction force applying mechanism using a compression spring has been described. However, the chair to which the present invention is applied is not particularly limited thereto. The present invention can also be applied to a chair having only one of a weight-responsive reaction force applying mechanism and a reaction force applying mechanism having a coil spring, for example, a non-weight sensing synchro locking mechanism in which the rear end side sinks while the seat moves backward in conjunction with the backward tilt of the backrest, a locking mechanism in which only the backrest tilts backward independently, or a locking mechanism in which only the seat performs a locking operation. Needless to say, the present invention can also be applied to a chair having no locking mechanism.

Explanation of Reference Numerals

[0086] 1 Leg 2 Main Frame 3 Seat 4 Backrest 5 Armrest 6 Back Frame 6a Upper Side 6b Side 6c Corner Portion 7 Backrest Support Member 8 Mesh Stretch Fabric (for Backrest) 9 Locking Member 9a First Cord 9b Second code 9c Third code 9d Fourth code 9e Corner part 10 Rear mounting seat 11 Rear bridge frame 12 Rear frame mounting part 13 Flange (rear frame mounting part) 14 Rear lower mesh mounting member (part of rear frame) 15 Grounding groove (of rear lower mesh mounting member) 16 Fastening screw 17 Contact surface (rear frame) 18 Grounding groove (of rear frame) 19 Front concave part on the side of rear frame 20 Lower side part of rear frame 21 Connecting part 22 Flange groove (for flange 13) 23 Vertical rib (flange groove 22) 24 Female screw (flange groove 22) 25 Bearing part (of backrest support member) 26 Arm part (of backrest support member) 27 Reaction receiving part (of backrest support member) 28 Bracket (supporting outer shell) 29 Elbow mounting seat 30 Seat support member 31 Outer frame 32 Front bridge frame 33 Bracket (behind seat frame) 34 Bearing part 35 Inner shell 35a Front side 35b Side 35c Corner part 35d Rear side 36 Grounding groove (inner shell) 37 Seat grounding 38 Locking member (for seat) 38a First code 38b Second code 38c Third code 38d Fifth code 38e Corner member 39 Ear part 40 Screw 41 Front link 42 Rear bracket 43 Backrest rotation axis 44 Sewing location of the locking member and the mesh tensioning area (i.e., the mounting location) 45 Tip side part on the inner side (opposite edge side) of the sewing location of the locking member 46 Base end side part on the outer side (edge side) of the sewing location of the locking member 50 Pad 51 Upper part (top surface part) of the pad 52 Outer side wall part of the pad 53 Inner wall part of the pad 54 Rear edge of the pad 55 First side locking claw 55a Leg part 55b Return part 55c Wedge part 56 Second side locking claw 57 Front locking claw 58 Rib 59 Front edge of the pad 60 Elbow rest body 61 Locking rib 62 Supporting rib 63 Through hole through which the first side locking claw of the pad penetrates 64 Engaging recess into which the second side locking claw of the pad fits 65 Engaging recess into which the front locking claw of the pad fits 66 Upper surface part of the upper side of the elbow rest body 67 Inner side surface part of the upper side of the elbow rest body 68 Outer side wall part of the upper side of the elbow rest body 69 Bottom part of the upper side of the elbow rest body 70 Upper side of the elbow rest body 71 Front side of the elbow rest body 72 Rear side of the elbow rest body 73 Bottom side of the elbow rest body 74 Mounting arm part of the elbow rest body The recess in the upper side of the 75 elbow rest body

Claims

1. In an armrest composed of an armrest main body and a pad placed on the upper surface thereof, a through hole that opens horizontally is provided in either the armrest main body or the pad, and when passing through the through hole to the other side, it shrinks, and after passing through the through hole, it expands and cannot pass through the through hole and functions as a slide prevention mechanism, and is provided with an elastically deformable first side locking claw, while an engaging recess that is recessed or penetrates in the same direction as the through hole is provided in either the armrest main body or the pad, and the other side is provided with a second side locking claw that protrudes in the same direction as the first side locking claw and is fitted into the engaging recess, By sliding the pad in the width direction of the armrest, the first side locking claw elastically deforms and passes through the through hole to engage, and the second side locking claw engages with the engaging recess, so that the pad is fixed in the three axial directions of the front-rear, left-right, and up-down directions with respect to the armrest main body. The mounting structure of the elbow pad of a chair, characterized by the above.

2. The first side locking claw includes a wedge portion that is obliquely intersecting with respect to the insertion direction into the through hole, a return portion that is locked to the edge of the through hole, and a leg portion having a length that passes through the through hole, and is an elastically deformable elastic body in a direction orthogonal to the insertion direction into the through hole. The mounting structure of the elbow pad of a chair according to Claim 1, characterized by the above.

3. The through hole opens in the width direction of the chair, and the mounting structure of the elbow pad of a chair according to Claim 1 or 2, characterized by sliding the pad in the width direction and fitting it.

4. A front locking claw is provided at the front edge portion of the pad, and a downward engaging recess into which the front locking claw of the pad is fitted is formed at the front end of the armrest main body. The engaging recess restricts the forward movement of the front locking claw of the pad, but is a cavity that allows movement in the width direction by at least the amount of lateral slide for attaching and detaching the pad. The mounting structure of the elbow pad of the chair according to any one of claims 1 to 3, characterized by the above.

5. A chair comprising an armrest to which the mounting structure of the elbow pad according to any one of claims 1 to 4 is applied.

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