JP7555249B2 - Chair back support cover - Google Patents

Description

Article 30, paragraph 2 of the Patent Act applies. ・Website posting date: November 17, 2020 ・Website address: https://www.kokuyo-furniture.co.jp/products/office/elua/ ・Publisher: Kokuyo Co., Ltd.

The present invention relates to a chair back support rod cover. More specifically, the present invention relates to an attachment structure for a back support rod cover that covers a back support rod that attaches a backrest to a main frame that supports the chair seat.

Traditionally, there have been chairs in which the backrest is attached to a back support rod that extends rearward from the main frame of the chair. In such cases, a back support rod cover is sometimes attached to hide the back support rod and prevent it from being exposed.

In addition, in the case of chairs in which the backrest is made by combining a rigid shell body and a cushion body and then covering the top with a bag-shaped upholstery, the lower part of the backrest is also exposed, so it is necessary to hide it with a cover material.

In that case, a cover that covers the back support rod and a cover that hides the bottom of the backrest are required (for example, see Patent Document 1). In the invention described in Patent Document 1, the bottom backrest cover and the back cover of the back support rod are molded as a single unit, and the back support rod cover is made up of these two members, including the front cover.

JP 2014-90996 A

However, when molding the lower backrest cover and the rear cover of the back support rod as a single unit, it is necessary to create a molded product with a three-dimensional shape, which results in a large part structure and increases the cost of the part. In other words, there is a problem that the equipment costs will increase because the mold will be larger.

In addition, in the case of the invention described in Patent Document 1, the final step in attaching the back support rod cover involves screwing the lower backrest cover to the lower backrest, which is inefficient in terms of work efficiency.

The present invention aims to provide a chair back support rod cover that can be easily attached using a small component structure.

To achieve this purpose, the back support rod cover described in claim 1 is composed of three parts: a lower back cover that covers the lower part of the chair backrest, a front cover that covers the front side of the back support rod, and a rear cover that covers the rear side of the back support rod. The lower back cover has an opening through which the back support rod passes, and the upper ends of the rear cover and the front cover are provided with edges that can be hooked onto the opening of the lower back cover, and the upper edges of the rear cover and the front cover are attached by hooking them onto the opening of the lower back cover, so that the opening is hidden by the edges.

Here, the under-back cover covers the opening at the lower end of the back panel, has an opening on the bottom surface that covers the opening at the lower end of the back panel, and has a slit through which the back support rod can be introduced and passed , and it is preferable that the slit is elastically deformed to widen the spacing between the slits to allow the back support rod to pass through .

The edge of the rear cover of the back support rod is preferably composed of a step that fills the gap between the edge of the opening of the lower back cover and the back support rod, and a flange that fits behind the edge of the opening, and the edge of the front cover of the back support rod is preferably composed of a flange that is inserted into the gap between the edge of the opening and the back support rod at a position displaced toward the back support rod from the surface of the front cover of the back support rod, and a step that covers the gap between the flange and the opening when the flange is inserted into the gap.

It is also preferable that the front cover of the back support rod and the back cover of the back support rod are each hooked and secured by a locking claw.

Furthermore, the present invention is a chair equipped with a back support rod cover according to any one of claims 1 to 4.

The support rod cover of the present invention is separated into three parts, so by combining the smaller parts, the mold can be made smaller, resulting in lower costs.

1 is a perspective view showing an embodiment of a chair to which the present invention is applied, viewed obliquely from below and behind. FIG. 2 is a front perspective view of the chair seen from diagonally below. FIG. 2 is a perspective view of the chair as seen from diagonally below, with the legs not shown. FIG. 2 is a central vertical cross-sectional view of a main part of the chair. 4 is an enlarged central vertical cross-sectional view showing the relationship between the back support rod and the back support rod cover of the chair. FIG. FIG. 2 is a central vertical cross-sectional view showing one embodiment of a backrest. FIG. 2 is a front perspective view showing one embodiment of a back panel, viewed obliquely from below. FIG. 2 is a perspective view of the back panel from the rear side. FIG. 13 is a perspective view showing the relationship between the back support rod, the main frame, and the back support rod cover. FIG. FIG. 13 is a perspective view showing one embodiment of a back support rod. FIG. 2 is an exploded perspective view showing one embodiment of a back support rod cover, viewed diagonally from below and behind. This is an exploded oblique view of the back support rod cover viewed diagonally from above in front. FIG. 2 is a top perspective view of the assembled back support rod cover. FIG. 2 is a bottom perspective view showing one embodiment of a cushioning material that constitutes a seat. FIG. 2 is a top perspective view showing one embodiment of a seat plate that constitutes a seat. FIG. 2 is a bottom perspective view of one embodiment of a main frame. FIG. 13 is a bottom perspective view of one embodiment of an instruction manual holder. 13 is a perspective view of the main frame with the instruction manual holder attached thereto, as seen from below. FIG. 1 is a vertical, partially sectional perspective view of a state in which an instruction manual holder is attached to a main frame. FIG. FIG. 11 is a perspective view showing another embodiment of a chair to which the present invention is applied, viewed diagonally from above and from the front.

The configuration of the present invention will be described in detail below based on one embodiment shown in the drawings. In the description in this specification, "upper", "lower", "front" and "rear", as well as "left" and "right" are defined based on the seated person sitting on the chair seat (in other words, "upper", "lower", "front" and "rear", as well as "left" and "right" as seen from the seated person). Furthermore, the front side of the backrest refers to the surface that comes into contact with the seated person, and the rear side refers to the surface opposite to that.

Figures 1 to 20 show one embodiment of a chair to which the present invention is applied. The chair of this embodiment comprises, for example, a leg 1, a main frame attached to and supported by the upper end of a support 2 of the leg 1, and a seat and backrest supported by this main frame.

In the present embodiment, as shown in Figs. 1 and 2, the leg 1 has, for example, five leg blades 7 arranged radially from the leg base 6 supporting the support 2, and is molded from a synthetic resin having rigidity, for example, glass fiber reinforced nylon such as PA6-GF (polyamide 6). In this embodiment, a caster 8 is provided at the tip of each of the five leg blades 7. In other words, the chair of this embodiment has legs in a form called a rotating leg. However, it is not essential for the present invention that the leg blades 7 are provided with casters 8, and furthermore, it is not essential for the present invention to adopt a leg of the leg blade type. In other words, the specific shape and form of the leg 1 of a chair to which the present invention can be applied are not limited to a specific one, and an appropriate one is selected appropriately based on the purpose and design of the chair.

In this embodiment, the length of the radially arranged leg wings 7 is set as short as possible compared to that of a typical office chair without impairing the anti-tip function, and the legs have a small leg radius. In other words, in consideration of use as a chair suitable for telecommuting, the legs are designed to fit under a narrow home desk. Of course, this does not exclude the length of the leg wings 7 being set to a large leg radius similar to that of a typical office chair.

In this embodiment, a gas spring with a locking mechanism is used as the support 2 of the leg 1, and is supported so as to be kept perpendicular to the floor surface by fitting into a through hole provided in the leg base 6 and pressing it in to be fixed.

The main frame 3 is attached to the tip of the support 2 (in other words, the upper end of the gas spring rod). At the tip of the gas spring rod, as shown in FIG. 4, an operation button 10 is provided for locking and unlocking the gas spring. The operation button 10 is operated to be pressed in and released by a lifting operation lever 11 that is attached to the main frame 3 so as to be able to swing. By operating the lifting operation lever 11, when the gas spring is unlocked, the main frame 3 (in other words, the seat 4 and backrest 5) can be raised and lowered, while when the gas spring is locked, the height position of the main frame 3 (in other words, the seat 4 and backrest 5) is fixed.

The main frame 3 supports the seat 4 and the backrest 5 via the back support rod 27. In this embodiment, for example, a steel plate is formed into a box shape with a flange portion 15 on the periphery as shown in FIG. 17 by deep drawing, and is fixed to the upper end of the support column 2 by press fitting. The flange portion 15 that protrudes outward from the periphery of the main frame 3 is placed on the underside of the seat plate 41 and fixed to the seat 4 by screws (not shown) that pass through the through holes 17.

In the center of the bottom of the main frame 3, a gas spring through hole 12 is opened through which the tip of the gas spring, which is the top of the support 2, passes. As shown in Figs. 20 and 4, the edge of the hole is bent inward to form a cylindrical shape, and a gas spring support cylinder 13 is fitted into the hole to fix the tip of the gas spring by a tight fit. The gas spring support cylinder 13 is supported by a bridging plate 14 whose upper end crosses the main frame 3. The bridging plate 14 is supported by a portion of the top of both side walls of the main frame 3, which is accommodated together with the flange portion 15 in a portion 16 that is recessed from the surrounding edges. In this embodiment, the bridging plate 14 accommodated in the recess 16 of the main frame 3 and the main frame 3 are fixed by welding or the like, but this is not particularly limited.

The bottom of the front side of the main frame 3 is formed with a slope that rises to the front, and a long hole 18 is provided in the widthwise center with its long axis positioned in the front-to-rear direction. On the other hand, the bottom of the middle region of the main frame 3, for example on the front side, is provided with a through hole 19 in the widthwise center. And, by utilizing the aforementioned long hole 18 and the rear through hole 19, a holder for storing instruction manuals (hereinafter referred to as instruction manual holder 23) can be attached to the back side of the bottom.

In addition, the bottom of the middle area of the main frame 3 is provided with an engagement claw (hereinafter referred to as the main frame side engagement claw 24) to which the engagement claw (hereinafter referred to as the back support rod side engagement claw 34) of the main frame mounting plate 29 at the tip of the back support rod 27 is hooked. In this embodiment, an independent claw member separate from the main frame 3 is attached using a pair of left and right claw attachment holes 20, so that the main frame side engagement claw 24 is formed on the back side of the bottom of the middle area of the main frame 3. Although not shown in detail in this embodiment, this main frame side engagement claw 24 is configured by bending a L-shaped claw portion 24a and multiple, for example, two insertion claw portions 24b that are bent at the base of the claw portion 24a and protrude horizontally so that they are perpendicular to each other. Therefore, the two insertion claw portions 24b are inserted into the two claw attachment holes 20 of the main frame 3, and then the main frame side engagement claw 24 is rotated 90° to be hooked to the bottom of the main frame 3. The main frame side engagement claw 24 may be fixed, for example, by not only hooking the bottom of the main frame 3 and the insertion claw 24b, but also by welding in some cases.

Furthermore, a recess (i.e., a seat surface that supports the spring) 21 is formed at the bottom of the rear area of the main frame 3 to accommodate the spring of the reaction mechanism (not shown). A hole 22 is drilled in the center of this recess 21, and a hanging bolt (i.e., a reaction force adjustment screw) connected to the spring is provided so as to protrude outside the main frame 3. Although the reaction force mechanism is not shown, in this embodiment, a reaction force mechanism using a spring is used that obtains a reaction force by compressing the spring when the backrest 5 tilts backward from the back support rod side engagement claw 34 at the tip of the back support rod. For example, although not shown, a reaction force spring and a plate that covers the upper part of the reaction force spring are provided in the main frame 3, and a reaction force adjustment screw extending downward from the plate penetrates the inside of the spring, the main frame 3, and a hole 33 in the main frame mounting plate 29 at the tip of the back support rod and engages with the grip 25. By turning the grip 25, the plate that serves as the spring lid is pulled toward or away from the seat, compressing or restoring the reaction spring that is located between the bottom of the main frame 3 and the plate, allowing the backrest backward tilt reaction force to be adjusted. In other words, although not shown, a reaction force is applied to the back support rod 27 by the reaction spring that is located between the plate at the head of the reaction adjustment screw and the bottom of the main frame 3.

In other words, in this embodiment, the backrest 5 is mounted so that it can rock by engaging the claws 24, 34 with the main frame 3 and tightening the tightening screw with the reaction spring interposed between them, and the backrest is supported so that it can rock (tilt and rock).

However, it is not essential for the present invention that the backrest be rockable; the seat and backrest may be configured to rock separately, or only one of the seat and backrest may be configured to rock, or even better, neither the seat nor the backrest may be configured to rock.

The back support rod 27 supports the backrest 5 and is attached to the main frame 3 so that it can swing freely. It is, for example, an L-shaped pipe when viewed from the side, and has a back panel attachment plate 28 attached to the back of the back panel 50 at its upper end, and a main frame attachment plate 29 attached to the main frame 3 by being hooked at its tip onto the main frame side engagement claw 24 of the main frame 3.

The back panel mounting plate 28, main frame mounting plate 29, and pipe 27 are each made of metal, such as steel, and are integrated by welding. In this embodiment, the back support rod 27 is made of two round pipes arranged in parallel and fixed to each other by the back panel mounting plate 28, main frame mounting plate 29, and connecting plate 30, but this is not limited to this and it may be, for example, a channel material or an elliptical pipe. In addition, a hole 31 is drilled in the center of the connecting plate 30 so that the reaction force adjustment screw of the reaction force mechanism can pass through.

11, the main frame mounting plate 29 has a downwardly protruding engagement claw 34 at its tip that hooks onto the main frame side engagement claw 24, and is provided with a hole 32 through which the support 2 passes and a hole 33 through which the reaction force adjustment screw passes. In this embodiment, the main frame mounting plate 29 is box-shaped with a pair of left and right side walls extending upward on both sides, and is provided to cover the outside of the main frame 3 by covering the rear half of the main frame 3. The main frame mounting plate 29 is attached to the main frame 3 so that it can swing by hooking the back support rod side engagement claw 34 at the tip onto the main frame side engagement claw 24 of the main frame 3 (specifically, the L-shaped claw portion 24a) with the tip of the support 2 penetrating the through hole 32 and entering the main frame 3. Then, the reaction force adjustment screw (not shown) is passed through the holes 31 and 33 on the rear side and tightened with the tightening grip 25 to be integrated. Furthermore, the front half of the main frame mounting plate 29 is inclined so as not to interfere with the supporting post 2 that passes through it, and is designed to keep the part that is tightened by the grip 25 horizontal.

The back panel mounting plate 28 at the rear end of the back support rod 27 is fixed to the mounting plate mounting base 59 on the back of the back panel 50, for example, by screwing it in place. In other words, the backrest 5 is fixed to the rear end of the back support rod 27.

The chair of this embodiment is designed to be assembled by the consumer who purchases the chair. That is, the seat 4 with the main frame 3 attached, the backrest 5 including the back support rod 27, and the legs 1 are supplied in a separate state, and the consumer is asked to assemble it themselves. More specifically, the back support rod 27 assembled to the backrest 5 is attached to the main frame 3 attached to the bottom surface of the seat 4, while the integrated seat 4 and backrest 5 are fixed by inserting them into the tops of the supports 2 of the legs 1.

However, in the case of chairs that require the purchaser to assemble them themselves, purchasers who do not properly understand how to assemble the chair may not know how to use the main frame side engagement claws 24, and may end up positioning the back mounting surface parallel to the screw before screwing it in. In this case, the main frame side engagement claws 24 and the back support rod side engagement claws 34 are not engaged, and the chair will not function properly.

To prevent assembly errors, as shown in Figure 20, a structure is adopted in which the back support rod side engaging claw 34 at the tip of the back support rod 27 is hooked from above onto the L-shaped main frame side engaging claw 24 of the main frame 3, while an instruction manual holder 23 is positioned so that it covers the main frame side engaging claw 24. This means that unless the back support rod side engaging claw 34 is correctly fitted into the main frame side engaging claw 24, the reaction force adjustment screw (not shown) that connects the main frame 3 to the main frame mounting plate 29 of the back support rod 27 will not protrude outside the main frame mounting plate 29. In other words, if the backrest parts cannot be set correctly on the main frame 3, the reaction force adjustment screw will not be tightened and assembly will not be possible.

That is, a part of the instruction manual holder 23 covers the outside of the main frame side engagement claw 24 and obstructs it, preventing the screw from jumping out of the main frame mounting plate 29. For example, a part of the instruction manual holder 23 is placed on the main frame side engagement claw 24, and a protrusion 35 is provided that protrudes in a direction away from the main frame 3, i.e., downward. When the main frame mounting plate 29 of the back support rod 27 rides up on this protrusion 35, the gap between the main frame mounting plate 29 and the main frame 3 increases, preventing the fastening screw from passing through the hole 33 in the main frame mounting plate 29, and preventing the back support rod 27 from being erroneously attached to the main frame 3. In other words, unless the back support rod side engagement claw 34 at the tip of the main frame mounting plate 29 of the back support rod 27 is inserted so that it fits inside the main frame side engagement claw 24, the fastening screw will not come out of the hole 33 of the main frame mounting plate 29 at the position where it passes through the hole 33 of the main frame mounting plate 29 because the protrusion 35 of the instruction manual holder 23 will be in the way. In other words, the main frame 3 and the back support rod 27 will not be connected to function properly.

Here, in the case of this embodiment, the instruction manual holder 23 is made of, for example, plastic, and as shown in Figures 18, 19, and 20, the four corners of the box part that holds the instruction manual are formed with claws 40 that hold the four corners of the instruction manual, and the rear end part is provided with a recess 36 that covers the main frame side engagement claw 24 and a pressing leg part 37 that also serves as a rib, and when attached to the main frame 3, as shown in Figure 20, a protrusion 35 that rests on the main frame side engagement claw 24 and hangs down from the rear end edge is integrally molded. This instruction manual holder 23 has, for example, a pair of claws (cross ribs) 39 that protrude on the back side, and an engagement claw 38 that protrudes on the back side at the rear side, and is attached by engaging each of the claws 38, 39 while elastically deforming with the long hole 18 and through hole 19 provided in the main frame 3.

In the present embodiment, the backrest 5 is composed of a back panel 50 supported by the back support rod 27, a cushioning material 51 such as molded urethane or slab urethane that is placed on the front side of the back panel 50, and a bag-shaped upholstery 52 that encases these.

Here, as shown in Figs. 7 to 9, the back panel 50 is formed in a shape that is generally convex toward the front in side view (i.e., a dogleg shape), and is made of a resin molded product that is curved to be generally convex toward the rear in plan view. This back panel 50 needs to be both lightweight and rigid enough to support the force of a seated person leaning against it. Therefore, the front side where the seated person leans against it, especially the back surface near the back support point where the seated person's lumbar vertebrae touch, is molded with a panel, and the back of the panel is made of a rib structure to ensure rigidity. On the other hand, the back panel structure can be omitted because the back panel does not come into contact with the seated person. Moreover, it is preferable that the back panel is molded with the rib structure exposed, in order to facilitate the mold structure and simplify the back panel structure. Therefore, in the case of this embodiment, the back panel 50 has an open structure in which the rib structure is exposed for the most part.

In addition, a downwardly facing inclined surface (hereinafter referred to as the skirt portion 54) with a widening recess is formed at the bottom of the back panel 50 to spread and anchor the lower edge of the bag-shaped upholstery 52 so that the back support rod mounting plate 28 and the back support rod 27 can be introduced inside the bag-shaped upholstery 52. In the present embodiment, the skirt portion 54 has an outer contour that is, for example, crescent-shaped when viewed from the bottom, and has a recess on the inside that is similar to the outer contour. Clips 61 are provided at multiple locations, for example, four locations each, at appropriate intervals on the inner wall surfaces of the front and rear sides surrounding the inner recess of the skirt portion 54, which hook the wire 53 on the edge of the bag-shaped upholstery 52 to fix the upholstery. Therefore, the bag-shaped upholstery 52 can be secured by covering the cushioning material 51 and the back panel 50 while leaving the mouth of the lower edge open by hooking the wire 53 on each clip 61. In addition, a female screw 62 for attaching the lower back cover 63 is provided at the bottom of the recess, so that the lower back cover 63 can be screwed in. Furthermore, an opening 55 is formed at the bottom of the recess, through which the back support rod attachment plate 28 and the back support rod 27 pass.

9, the upper side 56 and the lower side (i.e., the outer edge of the skirt portion 54) of the back panel 50 protrude rearward, and the back support rod 27 including the back panel mounting plate 28 and the inner rib area are located forward of the line segment connecting the upper side 56 and the outer edge of the skirt portion 54, which is the lower side. Also, above the mounting position of the back panel mounting plate 28 of the back panel 50, i.e., the mounting plate mounting seat 59, for example, between the mounting plate mounting seat 59 and the handle mounting seat 58, the back side is made into a panel 57, and the strength of the back panel 50 is ensured by forming a rib 60 on the front side. In other words, the back side of the back panel 50 is partially made into a panel. Therefore, the surface of the bag-shaped upholstery 52 stretched along the periphery of the back panel 50 is supported at three points on the back side: the upper side 56, the outer edge of the skirt portion 54, which is the lower side, and the panel 57 between them, and does not come into contact with the rib 60 in other areas. In other words, even if no cushioning material is provided on the rear side of the back panel 50, the ribs 60 will not come into contact with the upholstery 52 and rise above it, so the appearance will not be adversely affected.

In the case of a backrest structure in which the back panel 50 is completely covered with the bag-shaped upholstery 52, if the cushioning material 51 is placed on both the front and back sides of the back panel 50 to wrap it, the bag-shaped upholstery is supported by the cushioning material and the appearance of the backrest is not impaired, but the cushioning material on the back side is wasted because the seated person does not lean on it. On the other hand, it is not preferable to mold both the front and back sides of the back panel 50 into a panel shape because it increases the weight and increases the cost. Therefore, in the case of this embodiment, as shown in FIG. 6, the cushioning material 51 is provided only on the front side of the backrest 5. In other words, the cushioning material 51 is provided only between the front upholstery of the bag-shaped upholstery 52 and the back panel 50, and the cushioning material on the back side is omitted to reduce costs. In addition, the minimum necessary part of the back panel 50 is made into a panel shape, and the other part is formed with ribs 60 to ensure the necessary rigidity as the back panel 50.

However, if the cushioning material 51 is not placed on the rear side, the shape of the rib will stick out from the upholstery, resulting in a poor appearance. In other words, if the pouch-shaped upholstery touches the rib 60 on the rear of the back panel 50, the unevenness of the rib 60 will appear on the pouch-shaped upholstery 52, which could mar the appearance. To prevent this, the upholstery 52 is supported at three points: the upper edge 56, the lower edge (the outer edge of the skirt portion 54), and the flat portion 57 in the middle of the back panel 50, so that the upholstery 52 does not come into contact with the rib 60 and the rib 60 is not visible on the outside.

The upper part of the backrest 5 is provided with a handle 48 for easy carrying. The handle 48 is fixed, for example, by a screw to a handle mounting base 58 on the rear side of the back panel 50 from above the upholstery 52.

The ribs 60 that reinforce the back panel 50 are higher as they approach the center of the back panel 50 and lower as they approach the periphery, and are provided to provide soft support on the periphery of the back panel 50.

A support rod cover, preferably made of a relatively soft synthetic resin such as polyvinyl chloride, is attached to the support rod 27. The support rod cover is made up of three parts: a lower back cover 63 that fits over the lower end opening of the backrest 5, i.e., the skirt portion 54; a support rod front cover 64 that covers the front side of the support rod 27 below the lower back cover 63; and a support rod rear cover 65 that covers the rear side of the support rod.

The back cover 63 covers the lower end opening of the back panel 50, and is shaped to match the left-right curvature and front-rear thickness change of the back panel 50, as shown in FIG. 3 or FIG. 12 and FIG. 13, and has an opening 66 through which the back support rod 27 passes on the bottom surface 69 that covers the lower end opening of the back panel 50, and has a notch (slit 67) at one location for introducing and passing the back support rod 27 through the opening 66. This slit 67 only requires cutting out one location on the periphery of the opening 66, but in this embodiment, it is provided on the back side of the backrest 5, which is the least visible location (i.e., the location that is least visible from the outside). This part is hidden by the skirt part 54 from the normal line of sight. On the other hand, the front side wall surface 68 of the back cover 63 covers and conceals the lower edge of the backrest 5, and because it is exposed to the outside, even though it is hidden behind the seat 4, it may be visible from the front of the chair. Therefore, it is desirable that the front side wall surface 68 of the back cover 63 is a surface without slits. For this reason, in this embodiment, the edge that defines the opening 66 of the bottom surface 69 that closes the lower end surface of the back panel 50 of the back cover 63 is cut out by providing a slit 67 on the rear side. In addition, a screw fixing shaft portion (hole) 70 for passing a screw (not shown) is provided at a position of the bottom surface 69 corresponding to the female thread 62 on the inside of the skirt portion 54 of the back panel 50.

In this embodiment, the opening 66 is an oval hole through which the back support rod 27, which is made of two pipes arranged with a gap between them, is passed. A slit 67 is provided in the narrowest part of the bottom surface 69 that defines the opening 66, which is an oval hole. Therefore, the opening 66 is provided so that the relatively thin part of the back support rod 27 (i.e., the side of the back support rod 27) can pass through by elastically deforming so as to widen the edge part of the opening 66 of the bottom surface 69 separated by the slit 67 at the narrowest width, or to widen the spacing of the slit 67 by elastically deforming alternately up and down.

On the other hand, in the present embodiment, the back support rod front cover 64 has a top plate 78 and a pair of left and right side walls 79 extending downward from each of the left and right edges of the top plate 78, and is generally saddle-shaped with its rear half rising up so as to curve back along the L-shape of the back support rod 27, as shown in Fig. 12 and Fig. 13. Also, as shown in Fig. 5, a rib 71 is formed on the inner surface of the top plate 78 of the back support rod front cover 64, which acts as a spacer at the lowest position, for example, when the back support rod 27 is sandwiched between the top plate 78 and the back support rod rear cover 65, and the rib 71 is abutted against the back support rod 27, causing the inner surface of the top plate 78 to rise up so as not to come into contact with the back support rod 27.

The upper end of the back support rod front cover 64 is hooked onto the opening 66 of the back lower cover 63 and is provided with an edge that conceals the opening 66. For example, in this embodiment, the edge of the upper end of the back support rod front cover 64 is preferably composed of a flange portion 72 that is inserted into the gap between the edge of the opening 66 and the back support rod 27 at a position displaced toward the back support rod 27 from the surface of the back support rod front cover 64, and a step 73 that covers the gap between the flange portion 72 and the opening 66 when the flange portion 72 is inserted into the gap. Specifically, the flange portion 72 is formed to be inserted into the gap between the back lower cover 63 and the back support rod 27, i.e., into the inside of the opening 66. This flange portion 72 is formed with a step 73 so that it is displaced toward the back support rod side with respect to the upper end of the back support rod front cover 64, and is provided so that when the flange portion 72 at the tip is inserted into the gap between the back lower cover 63 and the back support rod 27, the upper end of the back support rod front cover 64 (above the step 73) covers and shields the gap between the flange portion 72 and the periphery of the opening 66 of the back lower cover 63. Note that in this embodiment, the edge of the upper end of the back support rod front cover 64 is composed of the flange portion 72 and the step 73, but this is not particularly limited, and it is sufficient to have at least the flange portion 72 that is inserted into the gap between the edge of the opening 66 and the back support rod 27.

As shown in Figs. 12 and 13, the back support rod front cover 64 has a plurality of, for example, three, engagement holes 75 spaced apart near the lower edge of the side wall 79, which engage with the locking claws 82 of the back support rod rear cover 65. The edge of this back support rod front cover 64 is formed with a protruding portion 74 that fits inside the back support rod rear cover 65, and is provided so that the edge abuts against the edge of the back support rod rear cover 65 and engages with it. In other words, the back support rod front cover 64 and the back support rod rear cover 65 are formed to fit together like a stomp joint. In this embodiment, a stomp joint is formed in which the protruding portion 74 is provided on one joint surface, for example the back support rod front cover 64, and a receptacle (stomp type) is created on the other joint surface, for example the back support rod rear cover 65, to connect them.

The front end of the support rod front cover 64 is formed with a claw 76 that fits into and clamps the edges of both side walls of the main frame mounting plate 29, and a step 77 that abuts against a stopper claw 84 on the front end of the support rod rear cover 65.

In this embodiment, as shown in FIG. 13, the back support rod cover 65 has a bottom plate 86 and a pair of left and right side walls 87 that extend upward from each of the left and right edges of the bottom plate 86, forming a box shape curved along the L-shape of the back support rod 27. The bottom plate 86 at the front of the back support rod cover 65 is hollowed out to form a recess 85 so as not to interfere with the grip 25. Furthermore, the upper part of this back support rod cover 65 is formed with wings 84 that jut out to the left and right like ginkgo leaves to enhance the design.

The inner surface of the bottom plate 86 is provided with a hook portion (i.e., a socket for the inro joint) 83 that supports the protruding portion 74 of the back support rod front cover 64 when the back support rod 27 is sandwiched between the back support rod front cover 64 and the bottom plate 86, and the upper edges of both side walls 87 are provided with multiple, for example, three, locking claw portions 82 that engage with the engagement holes 75 of the protruding portion 74 of the back support rod front cover 64. Furthermore, the tip of the back support rod rear cover 65 is provided with a stopper claw 84 that abuts against the step 77 of the back support rod front cover 64 to position it in the front-rear direction.

On the other hand, the upper end of the back support rod rear cover 65 is provided with an edge that is hooked onto the opening 66 of the lower back cover 63 and is attached to conceal the opening 66. For example, in this embodiment, it is preferable that the edge of the upper end of the back support rod rear cover 65 is composed of a step 80 that fills the gap between the edge of the opening 66 of the lower back cover 63 and the back support rod 27, and a flange 81 that fits behind the edge of the opening 66. Specifically, as shown in Figures 12 and 13, a step 80 that protrudes outward perpendicular to the back support rod rear cover 65 and fills the gap between the edge of the opening 66 of the lower back cover 63 on the side where the back support rod rear cover 65 is inserted and the back support rod 27, and a flange 81 that extends further outward from the lower edge of the step 80 and fits behind the back of the lower back cover 63 are formed. This flange portion 81 is formed so as to be displaced away from the back support rod 27 relative to the upper end of the back support rod rear cover 65, with a step. When the tip flange portion 81 and step portion 80 are inserted from bottom to top into the gap between the edge of the opening 66 of the back lower cover 63 and the back support rod 27, and then rotated 90 degrees from the upper end of the back support rod rear cover 65 as a starting point, the step portion 80 closes the gap between the back support rod 27 and the edge of the opening 66 of the back lower cover 63, and the flange portion 81 is fitted around and fitted onto the peripheral edge of the opening 66 of the back lower cover 63, so that it slips into the back side of the back lower cover 63 (i.e., the upper side in Figures 3 and 14) and becomes engaged. In this embodiment, the upper edge of the back support rod rear cover 65 is made up of a step 80 and a flange 81, but this is not limited to this and it is sufficient that it has at least a flange 81 that fits behind the edge of the opening 66.

The shape and height of the step 80 depend on the shape of the opening 66, since it fills the gap between the periphery of the opening 66 and the back support rod 27. In this embodiment, it is shaped like an oval halved along its long axis. On the other hand, the flange 81 is engaged by slipping into the back side of the back cover 63 and getting caught thereon, so there is no particular limit to its contour shape, but it is preferably, for example, rectangular and of the same length as the long axis of the step 80.

That is, the back support rod rear cover 65 of this embodiment covers the back support rod 27 from below, for example, and the step portion 80 and flange portion 81 at the upper end are hooked onto the back lower cover 63, and the locking claw portions 82 are hooked onto the engagement holes 75 on both side edges of the back support rod front cover 64, so that the back support rod rear cover 65 is suspended from the back support rod front cover 64. In other words, the back support rod front cover 64 and the back support rod rear cover 65 are connected, and the back support rod rear cover 65 is attached so that it is suspended from the back support rod front cover 64.

With the support rod cover constructed as described above, first, the slit 67 of the opening 66 of the under-back cover 63 is oriented toward the side of the support rod 27, i.e., toward the thin part of the pipe diameter only (i.e., the under-back cover 63 is oriented in a direction perpendicular to the backrest 5), and then the support rod 27 is passed through the slit 67 and placed in the opening 66. That is, the edge part of the opening 66 on the bottom surface 69 separated by the slit 67 is the narrowest, so it is easy to expand or to deform alternately up and down, and the spacing of the slit 67 can be changed to allow the relatively thin part of the support rod 27 to pass through.

After passing the back support rod 27 through the opening 66, the back cover 63 is twisted (rotated) 90 degrees and set so that it is attached to the inside of the skirt portion 54 at the bottom end of the backrest 5. Then, it covers the bottom end opening from above the upholstery 52 of the backrest 5, and screws are screwed into the screw holes 70 to fasten it to the skirt portion 54 at the bottom end of the back panel 50. This completely covers the bottom opening of the backrest 5 from above the upholstery, completing the end processing of the upholstery.

Then, insert the flange portion 81 at the top end of the back support rod rear cover 65 upward into the gap between the back support rod 27 and the edge of the opening 66 of the back lower cover 63, and then twist (pivot) it forward 90 degrees, so that the step portion 80 closes the above-mentioned gap.

Furthermore, the flange portion 72 at the upper end of the back support rod front cover 64 is fitted into the gap between the edge of the opening 66 of the back lower cover 63 and the back support rod 27, and is hooked onto the back support rod rear cover 65. When the flange portion 72 at the tip of the back support rod front cover 64 is inserted into the opening 66, the upper end of the back support rod front cover 64 (above the step 73) covers and shields the gap between the flange portion 72 and the periphery of the opening 66 of the back lower cover 63.

The upper ends of the back support rod front cover 64 and back support rod rear cover 65 are locked to the back lower cover 63, which is fixed to the backrest 5 with screws, and are connected to each other by the engagement of the locking claws 82 with the engagement holes 75. Furthermore, the claws 76 on the tip side fit with the edges of both side walls of the main frame mounting plate 29, the stopper claws 84 abut against the stepped portions 77, and the ribs 71 abut against the back support rod 27, so that they are held together with a certain distance between them without any gaps.

On the other hand, the seat 4 is composed of a seat plate 41, a cushion material 42 arranged on the seat plate 41, and an upholstery 43 which is a skin member that covers the cushion material 42. The seat plate 41 is placed on the main frame 3 and fixed, for example, with screws. In this embodiment, the seat upholstery 43 is fixed with a string.

Here, if the seat structure is one in which a flat cushioning material is placed on a flat seat plate 41, the seat does not fit the buttocks well, making the buttocks feel uncomfortable when sitting, or the seating posture is disrupted due to difficulty in maintaining a proper sitting posture. Furthermore, in chairs with a backrest, the buttocks may slip forward when the seated person leans against the backrest. Therefore, there is a chair that prevents forward slipping by forming a rigid outer shell into a recessed shape near the seated person's buttocks on the seat surface and fitting a flexible inner shell to the recessed shape of the outer shell (for example, JP 2014-90991 A). However, in this seat structure, it is necessary to recess the upper surface shape of the outer shell, and in order to form this recessed shape, it is necessary to create the outer shell by molding using a mold, which causes a problem of mold costs. In addition, the need for a flexible inner shell also leads to an increase in costs. Furthermore, the inner shell and outer shell must be made to be dedicated parts for a specific product, which results in low versatility. Therefore, it is desirable to use a seat that can prevent the buttocks from sliding forward without requiring an outer shell or inner shell that is formed with a recess near the buttocks of the seated person.

The seat 4 of this embodiment has a deflection promoting portion 44 formed on the underside 42a of the cushion material 42 in a portion of the area that includes the position of the seated person's buttocks when seated in a plan view, for example, rearward of the center position in the front-to-rear direction. In this embodiment, as shown in FIG. 15, for example, the deflection promoting portion 44 is formed by four linear grooves 45 of the same depth that extend in the left-right direction and are arranged at equal intervals in the front-to-rear direction, but it goes without saying that the shape is not particularly limited to this.

In other words, the seat structure of this embodiment is such that even if the top surface of the seat plate 41 is not concave, in other words even if it is flat, the flexibility-promoting portion 44 of the cushioning material 42 improves the fit to the buttocks when seated and prevents the buttocks from sliding forward.

Here, the deflection promoting portion 44 is intended to make a specific portion of the cushioning material 42 more easily deflectable than other portions, and is preferably, for example, a recess that opens downward.

The recesses 45 constituting the deflection promoting portion 44 are not limited to a specific shape, and may be, for example, continuous recesses, i.e., grooves, or intermittent or single recesses, i.e., depressions. In the case of grooves, they may be linear, as shown in FIG. 15, or may be wavy or other shapes, such as a shape imitating the contour of the buttocks including the base of the thigh (specifically, a generally forward-facing concave shape), although not shown. In the case of depressions, various depressions, such as hemispherical, conical, or pyramidal recesses (or recesses with hemispherical or pyramidal protrusions), may be formed, although not shown. These recesses 45 may be formed in one or multiple locations, or may be arranged so as to be surrounded by multiple layers in some cases. Furthermore, all of the recesses 45 may be the same size or depth, or may be different depths or sizes depending on the location. For example, the depth of the recess 45 may be made deeper or wider in the center of the area defining the bending promotion portion 44 than in the periphery, so that the center is more easily bent than the periphery, thereby adjusting the degree to which the buttocks sink.

Two or more of the above-mentioned straight grooves, wavy grooves, concave grooves, and hemispherical recesses or hemispherical protrusions or pyramidal recesses or protrusions may be used in combination. The depth of the above-mentioned recesses is not limited to a specific value, but is set to an appropriate value, taking into consideration, for example, the softness of the cushioning material 42 and the ease of bending desired to be expressed as the bending promotion portion 44.

The specific structure of the deflection-promoting portion 44 is not limited to a specific configuration or form such as a recess, as long as the portion is more easily deflected than other portions, and various configurations and forms can be selected as appropriate.

For example, the lower surface of the cushion material 42 may be uneven so that the area corresponding to the flexure-promoting portion 44 has more space (in other words, a cavity, a gap) than the other areas, so that the area corresponding to the flexure-promoting portion 44 is more easily flexed than the other areas. Alternatively, the area corresponding to the flexure-promoting portion 44 of the lower edge portion of the cushion material 42 may be made of a material that is more easily flexed than the other areas (in other words, a soft material), so that the area corresponding to the flexure-promoting portion 44 is more easily flexed than the other areas. In this case, the flexure-promoting portion 44 is appropriately set to an appropriate value, taking into consideration, for example, the softness of the cushion material 42 and the flexure desired to be expressed as the flexure-promoting portion 44. For example, a material is selected so that the material is gradually more easily flexed from the outer (periphery) portion of the buttocks to the inner (center) portion when seated, or a space (cavity, gap) is formed so that the cushion material 42 fits the buttocks better when seated, and the seated posture is stabilized.

The range of the flexure-promoting portion 44 is not limited to a specific range in a plan view of the seat, but is set appropriately based on the overall shape of the seat and the expected manner of use, and on the position of the occupant's buttocks when seated, to an appropriate range for sinking the buttocks and preventing forward slippage.

Specifically, for example, the range of the flexure promoting portion 44 is set to a range behind the center position in the front-to-rear direction in a plan view of the underside of the cushion material 42. In this case, a space (cavity, gap) as the flexure promoting portion 44 is formed only behind the center position of the front-to-rear direction on the underside of the cushion material 42, or more space is formed behind the center position of the front-to-rear direction compared to the area in front of the center position of the front-to-rear direction.

In this embodiment, the seat plate 41 is formed, for example, by pressing a steel plate, into a nearly flat plate with appropriate irregularities for increasing rigidity, as shown in FIG. 16. Here, the shape of the seat plate 41 is not limited to a specific shape, as long as it has at least a portion on the upper surface side that supports the cushion material 42 and at least a portion on the lower surface side that is attached to the main frame 3. The material of the seat plate 41 is also not limited to a specific type. Note that the seat plate 41 may be made of a single flat plate (including plywood) when, for example, the upper surface shape is to be completely flat. In some cases, it is preferable to form an air vent at the position of the deflection promoting portion 44 of the cushion material 42 in a plan view of the seat receiving member.

The material of the cushioning material 42 is not limited to a specific type as long as it is elastic and can be formed into any shape, and an appropriate material is selected as appropriate, taking into consideration, for example, the elastic force to be exerted and the ease of forming and processing. Specifically, for example, urethane (either molded urethane or slab urethane may be selected as the material of the cushioning material 42.

This seat 4, i.e., a seat in which the cushion material 42 has a flexure-promoting portion 44 at the buttocks of the seated person, makes the portion of the cushion material 42 at the buttocks more flexible and more easily concave than other portions, allowing the buttocks to sink, suppressing forward shifting of the seated person's buttocks and preventing forward sliding. It also improves the fit of the seat to the buttocks when seated, stabilizing the seated posture, improving seating comfort and improving the comfort of sitting, and ultimately the comfort of using the chair. Moreover, it is possible to make only the portion at the buttocks flexible without having a configuration with two shells, an inner shell and an outer shell, and it is possible to achieve the above-mentioned effects while keeping the seat configuration simple and low cost.

In other words, with this seat, the seat plate 41 is formed as a nearly flat surface, but the cushioning material deforms so that the seated person's buttocks sink in, so that forward slippage of the buttocks is suppressed, particularly when the upper body is tilted backward by leaning against the backrest and pushing backward, preventing forward sliding and stabilizing the seated posture. This makes it possible to improve the comfort of sitting by improving seating comfort, and ultimately the comfort of using the chair. Moreover, it is possible to make only the area where the buttocks are located flexible without having a structure with two shells, an inner shell and an outer shell, and it is possible to achieve the above-mentioned effects while maintaining a simple seat structure and low costs.

The above embodiment is one example of a preferred embodiment of the present invention, but is not limited thereto and can be modified in various ways without departing from the gist of the present invention. For example, the above embodiment has been described mainly as being applied to a chair that is assembled by the customer who purchased the chair, but it goes without saying that the present invention is not limited thereto and can be applied to a type of chair that is assembled in advance at a factory and then shipped. Also, in the above embodiment, a slit 67 is provided in the opening 66 of the lower back cover 63, and the slit 67 is elastically deformed to widen the gap so that the back support rod 27 passes through it from the side and is attached to the lower part of the back plate 50, but the present invention is not limited thereto and can be, for example, inserted from bottom to top or top to bottom into the opening 66 without providing a slit 67.

In the above embodiment, the backrest upholstery 52 is mainly described as being of a bag-wrapped type (upholstery sewn into a bag shape), but this is not particularly limited. In some cases, the upholstery material may be, for example, a mesh-like material.

In addition, the leg 1 in the above embodiment is not equipped with a footstool, but in some cases it may be equipped with one. When attaching a footstool to the leg 1, it is common to attach a ring-shaped or semicircular footstool to the support 2, or to place a footstool molded from a separate member on the leg blade 7 and fasten it to the leg blade 7 with screws or a band. However, as shown in FIG. 21, the footstool 9 may be molded integrally with the leg blade 7 by injection molding so that it straddles the space between adjacent leg blades 7. In this case, problems such as misalignment or insufficient fastening when attaching the footstool 9 can be avoided.

1 Leg 2 Leg support 3 Main frame 4 Seat 5 Backrest 24 Main frame side engagement claw
27 Back support rod 28 Back panel mounting plate 29 Main frame mounting plate 34 Back support rod side engagement claw 34 Back support rod side engagement claw 50 Back panel 51 Cushioning material 52 Bag-shaped upholstery 53 Wire 54 Skirt portion 55 Opening through which the back support rod passes 56 Top edge of the back panel 57 Face plate on the rear side of the back panel 58 Handle mounting base 59 Mounting panel mounting base 60 Rib 61 Clip for hooking the wire 62 Screw hole for attaching the back lower cover 63 Back lower cover 64 Back support rod front cover 65 Back support rod rear cover 66 Opening (back support rod through hole)
67 Slit 68 Side wall surface on the front side of the back cover 69 Bottom surface of the back cover 70 Screw fixing shaft portion (hole) of the back cover
71 Rib (spacer)
72 Flange portion of back support rod front cover 73 Step of back support rod front cover 74 Protruding portion of back support rod front cover that fits inside back support rod rear cover 75 Engagement hole of back support rod front cover 76 Claws 77 that fit into the edges of both side walls of the main frame mounting plate of the back support rod front cover Step portion of back support rod front cover that abuts against the stopper claws of the back support rod rear cover 78 Top plate of back support rod front cover 79 Side wall of back support rod front cover 80 Step portion of back support rod rear cover 81 Flange portion of back support rod rear cover 82 Engagement claws of back support rod rear cover 83 Hook portion of back support rod rear cover (i.e., serves as a socket for the spigot joint)
84 Wing portion of rear cover of back support rod 85 Recess through which grip passes 86 Bottom portion 87 Side wall portion

Claims (5)

It is made up of three parts: a back cover that covers the bottom of the chair backrest, a back support rod front cover that covers the front side of the back support rod, and a back support rod back cover that covers the back side of the back support rod.
The lower back cover is provided with an opening through which the back support rod passes,
The upper ends of the back support rod rear cover and the front support rod cover are provided with edges that can be hooked onto the opening of the back lower cover,
The back support rod rear cover and the back support rod front cover are attached by hooking the edges at their upper ends into the opening in the back lower cover, and the opening is concealed by the edges. The back support rod cover as described in claim 1, characterized in that the back under cover covers the opening at the lower end of the back panel, has the opening on its bottom surface that covers the opening at the lower end of the back panel, and has a slit in the opening for introducing and passing the back support rod , and is configured to elastically deform to widen the spacing of the slit to allow the back support rod to pass through. The edge of the back support rod rear cover is composed of a step portion that fills the gap between the edge of the opening of the back cover and the back support rod, and a flange portion that fits behind the edge of the opening,
A back support rod cover as described in claim 1 or 2, characterized in that the edge portion of the back support rod front cover is composed of a flange portion that is inserted into the gap between the edge of the opening and the back support rod at a position displaced toward the back support rod more toward the back support rod than the surface of the back support rod front cover, and a step that covers the gap between the flange portion and the opening when the flange portion is inserted into the gap. A back support rod cover according to any one of claims 1 to 3, characterized in that the front cover of the back support rod and the back cover of the back support rod are each hooked and secured by a locking claw. A chair equipped with a back support rod cover according to any one of claims 1 to 4.

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