JP2013070849A - Chair with backrest - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase strength without causing deterioration in aesthetic appearance in a chair in which a backrest is arranged on the front surfaces of back supports, and is secured with screws.SOLUTION: A back shell plate is divided into a lower back shell plate 9 and an upper back shell plate 10. The lower back shell plate 9 is integrally connected to a seat shell plate 8 through a hinge part 14. A back frame 7 connected to a base 6 has right and left back column supports 29, and the upper back shell plate 10 is fixed to the back column supports 29 with screws 31 inserted into the upper ends of the back column supports 29 from the back. A reinforcing plate 33 being horizontally elongated is arranged on the front surface of the upper back shell plate 10, and the screws 31 are threaded into the reinforcing plate 33. The strength is remarkably increased by the connection function of the reinforcing plate 33.

Description

  The present invention relates to a chair with a backrest.

  In a chair having a backrest, there is a type in which the backrest is supported by a support member disposed behind the backrest.

  For example, Patent Document 1 describes that left and right legs arranged on the left and right sides of a seat protrude above the seat, a horizontally long arm that protrudes inward is fixed to the upper end of the seat, and a backrest is fixed to the arm with a screw. Has been. In Patent Document 1, the backrest has a structure in which a resin-made back shell plate (core material) is covered with a skin material from the front and back, and the arm is also covered with the skin material on the back side.

  On the other hand, in Patent Document 2, in a chair having a seat shell plate and a back shell plate in an integrated structure, a back strut that stands up from the base disposed below the seat at the left and right middle portions of the backrest and is fixed to the back strut It is described that the back shell plate is fixed to the horizontally long bracket with screws. More precisely, in Patent Document 2, the seat and the backrest have an inner shell plate and an outer shell plate that supports the inner shell plate, and the seat inner shell plate and the back inner shell plate are manufactured as an integral structure product. At the same time, the seat outer shell plate and the back outer shell plate are also manufactured as an integral structure. The rear horizontal bracket is arranged in front of the back outer shell plate, and the back inner shell plate is fixed to the rear horizontal bracket.

JP 2006-204732 A Japanese Patent No. 2592108

  In both patent documents, the resin back shell plate is fixed directly to the arm or the horizontal bracket with screws, but the resin product has a lower strength than metal, so the thickness is increased to obtain the required strength. Such measures must be taken, which can make design difficult. In particular, there are cases in which two left and right back struts are placed behind the backrest, and the backrest is fixed to the upper end of the left and right back struts. When not used, the entire backrest tends to be twisted and deformed, so it is more troublesome to ensure the strength without increasing the thickness of the backrest.

  Now, when the whole of the seat shell plate and the back shell plate is molded as an integrated structure as in Patent Document 2, it becomes easy to ensure high rigidity as a whole, but a large mold is required for manufacturing. Manufacturing costs will increase. Therefore, it is advantageous in terms of cost if the shell plates are separated and connected. However, if the connection method is adopted in this way, the strength of the shell plate itself must be lowered. It can be said that the problem concerning the strength is likely to appear remarkably if it is only fixed to the back strut.

  Similarly, when the back shell plate tilts backward with respect to the seat shell plate, the back shell plate is weak against external forces such as torsion, so in this case as well, the back shell plate is simply fixed to the left and right back posts. Then, it can be said that the problem regarding strength tends to appear remarkably.

  The present invention has been made in view of such a situation, and in a chair formed by fixing a backrest to a back column disposed behind the chair, the back portion of the backrest is refreshed and high strength is ensured. It is.

  In the present invention, the backrest has a multilayer structure composed of a back shell plate, a cushion disposed at least on the front surface, and a skin material covering these from both the front and back sides, and a reinforcing plate disposed inside the skin material. And the back shell plate are fastened together with screws to a back column disposed behind the backrest.

  The present invention can be developed in various ways. Examples of this are specified in claims 2 and below. According to a second aspect of the present invention, in the first aspect, the reinforcing plate is disposed so as to overlap the front surface of the back shell plate. According to a third aspect of the present invention, in the first or second aspect, the back strut is divided into two parts on the left and right sides, and the reinforcing plate extends horizontally between the left and right back struts in a front view. It has become.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, the seat shell plate is manufactured separately for the upper back shell plate and the lower back shell plate, and both are connected, and the lower back plate is connected. The shell plate is integrally provided to the seat shell plate via a hinge portion, while the upper back shell plate is fixed to the back column, and the back column is disposed at the seat or below the seat. The backrest is connected to the base so as to be tiltable backward, and the backrest can be locked against the spring means.

  In the present invention, since the presence of the reinforcing plate can prevent stress from concentrating on a specific part, even if the back shell plate is made of resin, it is possible to ensure the strength against bending and twisting without excessively thickening. it can. Moreover, since it is hidden in the inside covered with the skin material, it does not impair the beauty. Therefore, the strength required for the backrest can be maintained without deteriorating the aesthetic appearance or excessively thickening. The reinforcing plate is preferably made of a metal such as a steel plate.

  If the structure of Claim 2 is employ | adopted, since a back shell board is pinched | interposed between a reinforcement board and a back support | pillar, it is excellent in especially strength. Further, the structure of claim 3 is particularly suitable because it has a simple structure in which the backrest is fixed to the two left and right back posts, but the strength can be secured by the horizontally long reinforcing plates.

  As a fastening means by screws (screws, bolts), it is possible to weld a nut to the reinforcing plate or to make a simple tapped hole in the reinforcing plate, but it takes time and effort to weld the nut. In the method of making a simple tapped hole, there is a possibility that the reinforcing plate becomes thicker than necessary in order to secure the screw allowance. On the other hand, when the burring portion is provided as in the embodiment and the female screw is formed thereon, there is an advantage that the screwing function of the screw can be maintained without making the reinforcing plate thicker than necessary.

  When the structure of claim 4 is adopted, the seat shell and the backrest are integrated on the exterior, but the back shell plate is divided into upper and lower parts, thereby avoiding the enlargement of the mold and reducing the manufacturing cost. Since the back shell plate can be restrained and the back shell plate tilts backward with respect to the seat shell plate, the back shell can be tilted backward with no or almost no back tilt. For this reason, it is possible to give the backrest a locking function while the chair and the backrest are integrated in appearance. The strength is also ensured by the presence of the reinforcing plate. Therefore, in the invention of claim 4, it is possible to manufacture a back seat integrated type chair that is excellent in the locking function and secures the strength while suppressing the cost as much as possible.

It is a figure which shows the external appearance of the chair which concerns on embodiment, (A) is a front view, (B) is a side view, (C) is a top view, (D) is a rear view, (E) is a partial perspective view. is there. (A) is the whole isolation | separation perspective view, (B) is the isolation | separation perspective view in the state which turned over the base. (A) is a separated perspective view of a shell plate and a reinforcing plate, and (B) is a separated perspective view of a cushion. FIG. FIG. 5 is a side sectional view of a portion centered on a seat as seen from the VV viewing direction of FIG. 4. FIG. 6A is a partial cross-sectional view taken along the line VIA-VIA in FIG. 5, and FIG. FIG. 7 is a partial sectional view taken along the line VII-VII in FIG. 5. (A) is the isolation | separation perspective view which looked at the body receiving part from back, (B) is the partial perspective view which looked at the lower back shell board from the downward direction. (A) is a separated perspective view of the upper back shell plate and the reinforcing plate, (B) is a perspective view of the lower portion of the upper back shell plate as viewed from the rear, and (C) is a cross-sectional view taken along the line CC of (A). is there. It is a separation plane sectional view of an upper back shell board, a reinforcing board, and a back support. It is sectional drawing after the assembly seen in the location of FIG. (A) is a separated front view of the back shell plate, (B) is a sectional view taken along the line BB of (A) in the connected state, (C) is a sectional view taken along the line CC of (A) in the connected state, (D) is DD sectional view taken on the line (A) in the connected state. It is a vertical side view which shows the relationship between a shell board and a cushion.

  Next, an embodiment of the present invention will be described with reference to the drawings. In the following description, the words “front and rear” and “left and right” are used to specify the direction, but these words are based on the direction of the person who is normally seated. However, the front view refers to the direction facing the seated person. The words “inside” and “outside” are also used, but the direction facing the center of the chair in front view is inward, and the direction from the center of the chair toward the left and right outside in front view is outward.

(1). Outline of Chair First, the outline of the chair will be described with reference to FIGS. The present embodiment is applied to a swivel chair. As shown in FIG. 1, the chair includes a body receiving portion 3 in which a seat 1 and a backrest 2 are integrally continuous, a leg device 5 having a leg column 4, and a leg. It has a base 6 attached to the upper end of the support column 4 and a back frame 7 connected to the base 6 so as to be able to tilt backward. The leg device 5 has branch legs extending in the radial direction, and a caster is provided at the tip of each branch leg. The base 6 and the back frame 7 are an aluminum die cast product or a resin molded product.

  As shown in FIG. 1 (B), there is a space between the rear surface of the base 6 and the front end of the lower portion of the back frame 7, but the space is in a state where the back frame 7 is tilted by locking. Even so, it is set so that a dimension larger than that of a normal adult finger is maintained. Therefore, even if a person inserts a fingertip into the gap between the base 6 and the back frame 7, the person is not caught.

  As can be understood from FIGS. 2 and 3, the body receiving portion 3 has a shell plate and a cushion formed integrally therewith. The shell plate includes a seat shell plate 8 constituting the seat 1, a lower back shell plate 9 integrally connected to the rear portion of the seat shell plate 8, and an upper back shell plate 10 that is separate from the lower back shell plate 9. And the lower end portion of the upper back shell plate 10 is connected to the upper end portion of the lower back shell plate 9. Therefore, the shell plate of the backrest 2 is constituted by the upper and lower back shell plates 9 and 10. The shell plates 8, 9, and 10 are resin molded products, and a plurality of reinforcing ribs extending in the vertical and horizontal directions are formed on the back surface.

  Note that the words “lower” and “upper” used for the back shell plate are used to specify two elements that are divided into upper and lower parts, and are not used to specify the height position. Absent. Therefore, the upper back shell plate 10 may constitute a large part of the backrest 2 (about 70 to 80%) as in the present embodiment, or the lower back shell plate 9 may constitute the majority of the backrest 2. In some cases, the upper and lower shell plates 9, 10 are about half as high.

  As shown in FIG. 3 (B), the cushion is divided into a lower cushion 11 corresponding to the seat shell plate 8 and the lower back shell plate 9, and an upper cushion 12 corresponding to the upper back shell plate 10. These cushions 11 and 12 are insert-molded on the shell plates 8, 9 and 10, respectively. As can be understood from FIG. 13, the lower cushion 11 covers the entire surface of the seat shell plate 8 and the lower back shell plate 9, and winds up to the back side of the end edges of the seat shell plate 8 and the lower back shell plate 9. Molded. On the other hand, the upper cushion 12 is formed so as to wrap the entire front and rear surfaces of the upper back shell plate 10.

  The body receiving part 3 has a skin material 13 having an integral structure, and a portion of the skin material 13 located on the backrest 2 covers the back shell plates 9 and 10 and the cushions 11 and 12 before and after the back shell plates 9 and 10 from above. The part corresponding to the seat 1 in the skin material 13 is wound downward from the outer periphery of the seat shell plate 8.

  The seat shell plate 8 and the lower back shell plate 9 are divided by slits 15 except for the hinge portions 14 at both left and right ends. In other words, the seat shell plate 8 and the lower back shell plate 9 are integrally connected only by the hinge portions 14 at both left and right ends. For this reason, the lower back shell plate 9 (backrest 2) can tilt backward relative to the seat shell plate 8 (relative to the seat 1) due to elastic deformation of the hinge portion 14. The slit 15 is formed in a U shape in plan view with its left and right ends extending forward, and therefore the hinge portion 14 is located in front of the rear end of the seat shell plate 8.

  As shown in FIGS. 2 and 4, the base 6 has a generally rectangular shape in plan view and has a frame structure opened upward and downward. For this reason, the base 6 includes a rear member 16, left and right side members 17, and a front member 18. A leg strut mounting hole 19 is formed in the left and right middle part of the rear member 16, and a rearward projecting part 20 is formed at the rear end part of the rear member 16, and the back frame 7 is a laterally long support shaft on the rearward projecting part 20. 21 is rotatably connected. There is a space between the base 6 and the back frame 7 on both the left and right sides of the rearward projecting portion 20, and as described above, this space is an interval that does not hold a finger.

  As shown in FIGS. 2 and 4, longitudinal rail members 22 are slidably attached to the left and right side members 17 of the base 6, and a seat shell plate 8 is attached to the rail members 22. The rail member 22 moves backward against the spring 23 incorporated therein.

  For example, as shown in FIG. 2 (A), the back frame 7 has a laterally long base 24 that forms the lower end of the back frame 7, and the left and right intermediate portions of the base 24 are connected to the base 6 via a bearing bracket 25. It is connected to the rearward projecting portion 20 by a support shaft 21. Similarly, as can be understood from FIG. 2A, upward bearing ribs 27 located between the left and right bearing portions 26 provided at the rear end of the rail member 22 are provided at the left and right ends of the base 24 in the back frame 7. And a bearing portion 26 of the rail member 22 and a bearing rib 27 of the back frame 7 are connected by a horizontally long pin 28.

  Back struts 29 are formed integrally with the left and right ends of the base 24 in the back frame 7 and are raised backwards and then raised upward. The bosses 30 project forward from the upper ends of the back struts 29. The upper back shell plate 10 is fastened with screws (screws) 31.

  A horizontally long recess 32 that opens forward is formed in the lower part of the front surface of the upper back shell plate 10, and a horizontally long reinforcing plate 33 made of metal (steel plate) is fitted in the recess 32, and screw 31 is screwed into a burring portion 34 formed on the reinforcing plate 33. Therefore, the back column 29, the upper back shell plate 10, and the reinforcing plate 33 are fastened together with the screws 31.

  At the upper end of the back strut 29, an elbow body 36 that is bent outwardly from the left and right and extends forward is integrally formed. The elbow body 36 is attached with an elbow cover 37 that covers the entire upper surface. Yes. The elbow cover 37 is integrally formed with a downward rear wall 37 a that covers the upper portion of the back column 29 from behind.

(2). Supplementary Explanation of Support Mechanism Next, details of each part will be described with reference to FIG. First, the support mechanism part centering on the base 6 is demonstrated.

  As described above, the back frame 7 is connected to the rearward projecting portion 20 of the base 6 through the bearing bracket 25 at the left and right intermediate portions. However, as shown in FIG. 2 (A) and FIG. The base 24 is formed with a recess 41 into which the bearing bracket 25 is fitted so that it cannot be displaced laterally. A screw 42 inserted into the base 24 of the back frame 7 from above is screwed into the bearing bracket 25. The support shaft 21 passes through a side plate 20 a provided in the rearward projecting portion 20 of the base 6, and is held by a recess 41 of the base portion 24 in the back frame 7 so that it cannot be removed from the left and right.

  Next, the location of the rail member 22 will be described. As shown in FIGS. 6 to 7, the rail member 22 has a channel-like (U-shaped) shape that opens downward, and the seat shell plate 8 has a pair of left and right downward regulating ribs 43 that surround the rail member 22 from both left and right sides. It is provided one by one. As shown in FIG. 6B, the downward regulating rib 43 is integrally provided with positioning ribs 44 that are close to the rail member 22 from the inside and outside, and the front and rear longitudinal stoppers 45 cut and raised on the rail member 22 are formed. The engaging claw 46 formed on the downward regulating rib 43 is applied from below. Therefore, the seat shell plate 8 is held so as not to be separated upward with respect to the rail member 22, and the seat shell plate 8 and the rail member 22 can be relatively moved in the front-rear direction.

  As shown in FIGS. 5 and 6A, a horizontally long guide pin 47 is inserted through the front end portion of the rail member 22 so as not to move back and forth. As shown in FIG. Is inserted through a guide hole 49 formed in a guide body 48 fixed to the side member 17 of the base 6. The guide hole 49 is a long hole in the longitudinal direction (see FIG. 5), so that the rail member 22 can slide back and forth together with the seat shell plate 8.

  As shown in FIGS. 5 and 7, a front spring receiver 50 is attached to the front / rear intermediate portion of the rail member 22 to support a spring (compression coil spring) 23 from the front side. The rear end of the spring 23 is supported by a rear spring receiver 51 fixed to the side member 17 of the base 6. Therefore, the rail member 22 can move backward against the elasticity of the spring 23. Since the rear end of the rail member 22 is connected to the back frame 7, when the seated person leans against the backrest 2 and the back frame 7 tilts backward, the rail member 22 moves backward and the backrest 2 tilts backward. .

  In this case, since the upper back shell plate 10 is fixed to the upper end of the back column 29, the upper back shell plate 10 rotates about the support shaft 21, whereas the seat shell plate 8 is a rail member. Since the shell plates 8, 9, and 10 have a rigid structure, the movement of the seat shell plate 8 and the movement of the back shell plates 9, 10 are restricted and cannot be locked. However, in this embodiment, the seat shell plate 8 and the lower back shell plate 9 are connected via the hinge portion 14 that can be elastically deformed. As shown in FIG. 5, a base cover 52 is attached to the upper surface of the rear member 16 in the base 6.

(3). Structure of the backrest Next, the structure of the backrest 2 will be described. For example, as shown in FIG. 8, a large number of reinforcing ribs 54 extending in the vertical and horizontal directions are formed on the back surfaces of the lower back shell plate 9 and the upper back shell plate 10. The hole 55 is vacant. The upper and lower back shell plates 9 and 10 are insert-molded with cushions 11 and 12 on both the front and back surfaces. During insert molding, the resin material passes through the window hole 55 and the back shell plates 9 and 10 Go around the back.

  As described above, the upper back shell plate 10 constitutes a substantial portion (about 70%) of the total height of the backrest 2. Overlapping portion rib plates 56 and 57 are formed on the lower surface of the upper back shell plate 10 and the upper surface of the lower back shell plate 9, respectively. A mating projection 58, side engagement projections 59 located at both left and right ends, and an intermediate positioning projection 60 located between the center engagement projection 58 and the side engagement projection 59 are provided to project downward.

  On the other hand, on the upper portion of the lower back shell plate 9, a center pocket portion 61 into which the center engaging projection 58 is fitted, a side pocket portion 62 into which the side engaging projection 59 is fitted, and an intermediate pocket portion into which the intermediate positioning projection 60 is fitted. 63 is opened upward. As shown in FIG. 12, the center engaging projection 58 is formed with an engaging claw 58a projecting obliquely upward, and this engages and engages with a center engaging hole 61a provided in the center pocket portion 61 from below. Yes.

  Similarly, the side engaging projection 59 is formed with an engaging claw 59a that protrudes obliquely upward, and this engaging claw 59a is engaged with the side engaging hole 62a provided in the side pocket portion 62 from below. doing. The center engaging protrusion 58 is tilted toward the rear side, and the side engaging protrusion 59 is tilted toward the front side. Further, the projections 58, 59, 60 are fitted into the lower back shell plate 9 in the order of the side engagement projection 59, the center engagement projection 58, and the intermediate positioning projection 60.

  The overlap portion rib plate 57 of the lower back shell plate 9 has a shape in which a considerable range including the intermediate portion thereof is recessed downward in a front view, while the overlap portion rib plate 56 of the upper back shell plate 10 is A considerable range including the left and right intermediate portions protrudes downward. That is, the mating surfaces of the upper and lower back shell plates 9 and 10 are uneven as viewed from the front. And the inner side surface 57a of the recessed part of the overlap part rib plate 57 in the lower back shell plate 9 is inclined, and the intermediate pocket part 63 is formed in a state straddling the bottom surface of the recessed part and the inclined inner side surface 57a. Yes. On the other hand, the outer surface 56a of the convex portion of the overlapping portion rib plate 56 in the upper back shell plate 10 is also inclined, and the intermediate positioning projection 60 is formed in a state straddling the lower surface and the inclined surface of the convex portion. .

  For example, as shown in FIG. 9, the lower portion of the upper back shell plate 10 is bent in a concave shape in a plan view, and the reinforcing plate 33 disposed below the upper back shell plate 10 is also bent in a forward shape in a plan view. doing. That is, a considerable range including the intermediate portion of the reinforcing plate 33 is a base portion extending in a horizontally long straight line in a plan view, but a certain range near both the left and right ends includes an inclined portion 33a bent toward the front side. In addition, a laterally long end portion 33b is formed at the tip of the inclined portion 33a in plan view. A burring portion 34 is projected forward from the end portion 33b. As shown in FIGS. 10 and 11, a screw 31 is screwed into the female screw formed on the burring portion 34 from behind.

  Naturally, the upper back shell plate 10 has a screw insertion hole 64. The upper back shell plate 10 is formed with a receiving seat 65 into which the boss portion 30 of the back column 29 is fitted. As shown in FIG. 9B, the receiving seat 65 is formed in a state surrounded by ribs 66. In addition, a counterbore 67 into which the head of the screw 31 enters is formed on the back surface of the back column 29 at the location of the boss 30. Note that a nut may be welded to the reinforcing plate 33 instead of forming the burring portion 34.

  The reinforcing plate 33 is formed with left and right horizontally elongated ribs 68 for reinforcement except for the end portion 33b. Further, positioning holes 69 are provided in the left and right ends of the base portion and the end portion 33b of the reinforcing plate 33, and positioning pin portions 70 that fit into the positioning holes 69 are provided on the upper back shell plate 10 so as to project. . The end portion 33b has a pair of upper and lower positioning holes 69. Further, as shown in FIGS. 9A and 9C, holding claws 71 for holding the reinforcing plate 33 from above and below are provided at portions of the upper back shell plate 10 corresponding to the left and right ends of the base portion of the reinforcing plate 33. Forming. When the reinforcing plate 33 is strongly pushed into the recess 31, the holding claw 71 is elastically deformed and then returned to the original, so that the reinforcing plate 33 is held so as not to drop off.

  As shown in FIG. 2A, an upper hook-like lower engaging claw 72 is projected from the front surface of the back column 29 at a substantially middle height position in the vertical direction. On the other hand, as shown in FIG. 8, on the back surface of the lower back shell plate 9, a pocket-shaped lower receiving portion 73 having an upward opening into which the lower engaging claw 72 is fitted from above is formed. Therefore, the lower back shell plate 9 is also connected to the back column 29 so as not to be separated from the front and rear. The lower back shell plate 9 and the back column 29 can be fastened with screws. However, when the engaging means including the engaging claw 72 and the receiving portion 73 is employed as in this embodiment, the assembly is simple. In addition, there is an advantage that the back surface of the back column 29 is clean.

(4) Summary In the above configuration, the left and right back struts 29 are independent from each other. Therefore, simply fixing the upper back shell plate 10 to the back strut 29 requires that the upper back shell plate 10 be thick. Although there is a possibility that strength against external force such as torsion cannot be secured, in the present invention, since the left and right back struts 29 are integrally connected by the presence of the reinforcing plate 33, the upper back shell plate 10 is excessively moved. The strength of the entire chair can be ensured without increasing the thickness.

  And since the reinforcement board 33 is arrange | positioned in the front surface of the upper back shell board 10, only the back support | pillar 29 is exposed behind the backrest 2, Therefore The chair back surface is refreshed and the appearance is good. In addition, since the reinforcing plate 33 can be assembled in a state where it is set on the upper back shell plate 10 in advance, even if the backrest 2 is a chair of a stool type covered with a skin material 13 from the front and back, it can be assembled without any trouble. Yes. Furthermore, since the screw 31 is screwed from behind, the assembly is easy, but in this embodiment, the head of the screw 31 is exposed because the head of the screw 31 is covered by the rear wall 37a of the elbow cover 37. Deterioration of the appearance due to can also be prevented.

  In addition, if the seat shell plate 8 and the back shell plates 9 and 10 are integrally structured, the seat shell plate 8 and the back shell plates 9 and 10 can be manufactured only by a special large molding machine, which may increase costs and prevent timely manufacture. However, in this embodiment, since the back shell plate is separated into the upper and lower shell plates 10 and 9, the back shell plate can be manufactured using a widely used molding machine. Timely production becomes possible. Further, the reinforcing plate 33 can prevent the strength from being lowered due to the back shell plate being separated into the upper and lower sides.

  Further, in the present embodiment, the lower back shell plate 9 is connected to the seat shell plate 8 only by the hinge portion 14, so that the seat 1 can be horizontally slid to lock the backrest 2 backward when locking, The lower body of the seated person has the advantage that the back tilt angle of the backrest 2 can be increased as much as possible without changing the posture. And if the upper and lower back shell plates 9 and 10 move freely, it becomes easy to twist by an external force, and in order to avoid this, the upper and lower back shell plates 9 and 10 and the back frame 7 must have a sturdy structure. Since the left and right back struts 29 are in the same state as being connected by the reinforcing plate 33, the required strength can be ensured without excessively thickening the upper and lower back shell plates 9, 10.

  When the holding claw 71 that holds the reinforcing plate 33 from above and below is provided as in the present embodiment, the reinforcing plate 33 is positioned, and thus there is an advantage that the screw 31 can be screwed in accurately. Other structures can be used as the positioning means, and can be fixed to the shell plate by insert molding, for example.

(5). Others The present invention can be embodied in various ways other than the above embodiment. For example, the application target chair is not limited to a swivel chair or a back seat integrated system, but can be applied to various types of chairs. The back strut is not limited to the two left and right system, but may be a single system. The shape of the reinforcing plate can be arbitrarily set as necessary. It is also possible to use a plurality of upper and lower reinforcing plates.

  When the present invention is applied to a chair in which a seat and a backrest are integrated, the seat shell plate and the back shell plate can be configured as a single body. Moreover, when it is set as 2 parts structure, it is also possible to isolate | separate into a seat shell board and a back shell board. It is also possible to arrange the reinforcing plate behind the back shell plate or to arrange the reinforcing plate on both the front and back sides of the back shell plate.

  The present invention can be embodied in a chair. Therefore, it can be used industrially.

1 seat (seat)
2 Backrest (back)
DESCRIPTION OF SYMBOLS 3 Body receiving part 6 Base 7 Back frame 8 Seat shell board 9 Lower back shell board 10 Upper back shell board 11, 12 Cushion 29 Back support 30 Boss 32 Recess 31 Screw 33 Reinforcement board 37 Elbow cover

Claims (4)

The backrest has a multilayer structure composed of a back shell plate, at least a cushion disposed on the front surface, and a skin material covering these from both sides of the front and back, and a reinforcing plate disposed inside the skin material and the back shell The plate and the back strut disposed behind the backrest together with screws,
Chair with backrest. The reinforcing plate is disposed on the front surface of the back shell plate,
A chair with a backrest according to claim 1. While the back strut is divided into two left and right, the reinforcing plate is in a horizontally long form extending between the left and right back struts in a front view.
A chair with a backrest according to claim 1 or 2. A seat shell plate is manufactured separately for an upper back shell plate and a lower back shell plate, and both are connected, and the lower back shell plate is integrally provided on the seat shell plate via a hinge portion. On the other hand, the upper back shell plate is fixed to the back strut, and the back strut is connected to the seat or a base disposed below the seat so as to be able to tilt backward, and the backrest resists spring means. And can be locked,
The chair with a backrest as described in any one of Claims 1-3.

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