chair

Abstract

To improve ease in fitting a mesh material and design in a mesh type backrest.SOLUTION: A backrest 4 is a structure in which a seat material 18 (a mesh material) is stretched over a back frame 17. A side member 19 of the back frame 17 is a cross-sectional triangular shape having a front surface 26, an outer peripheral surface 27, and an inner peripheral surface 28. The seat material 18 is wound behind the side member 19 and reaches the inner peripheral surface 28, is exposed on the outer peripheral surface 27, and is covered with a side cover 70 on the inner peripheral surface 28. Since the seat material 18 covers the outer peripheral surface 27, a mesh type is emphasized in a back view. As the seat material 18 is fixed to the inner peripheral surface 28, fitting is easy with the seat material 18 stretched tightly, while a fixing part of the seat material 18 is covered with the side cover 70, so that an appearance does not worsen.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a chair having a backrest structure in which a flexible sheet such as a mesh material is stretched over a back frame with openings at the front and rear. [Background technology]

[0002] It is common for chairs to have a mesh-type backrest, where the back frame is open at the front and back and is covered with mesh material. Mesh-type backrests are not only functionally superior in terms of breathability and cushioning, but also highly acclaimed for their clean appearance and design.

[0003] While mesh-type chairs have many advantages, the problem is how to attach the mesh material to the back frame in a taut, secure, and beautiful manner. In this regard, Patent Document 1 discloses a method in which a tape-like edging material is fixed to the outer edge of the mesh material (upholstery material), while a groove is formed on the outer surface of the back frame and the edging material is fitted into the groove.

[0004] On the other hand, Patent Document 2 discloses that when the back frame is made of a resin member, the back frame is molded with a mesh material fixed to a mold. That is, Patent Document 2 discloses that the mesh material is fixed to the back frame by an insert molding method. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-255076 [Patent Document 2] Japanese Patent Application Laid-Open No. 2002-240817 Summary of the Invention [Problem to be solved by the invention]

[0006] There are cushion types of chair backs in which cushioning material is placed on the front of the inner shell (backboard) and covered with a covering material. Mesh-type backrests are thinner than cushion types and have a unique, clean aesthetic appearance. However, in Patent Documents 1 and 2, the edges of the mesh material are exposed on the outer periphery of the back frame, which may cause discomfort to some people, and therefore it cannot be said that they are necessarily satisfactory in terms of aesthetics.

[0007] Furthermore, in the case of Patent Document 1, when attaching the mesh material to the left and right side members of the back frame, one edge material must be fitted into the groove of one side member, and then the other edge material must be fitted into the groove of the other side member while the mesh material is pulled tightly, making the work of attaching the mesh material troublesome.

[0008] In contrast, in the case of Patent Document 2, although attaching the mesh material is not time-consuming, it is not necessarily easy to hold the mesh material in a mold while it is under tension, so it is not easy to obtain a backrest with a taut mesh material. Another problem with Patent Document 2 is that the mesh material cannot be replaced.

[0009] It is also possible to form the entire mesh material into a bag shape and then completely cover the back frame from above, or to form the outer periphery of the mesh material into a bag-like portion and fit the bag-like portion into the back frame. When the entire mesh material is formed into a bag shape, the mesh material simply overlaps the back frame, which can cause problems such as making it difficult to keep the mesh material taut.

[0010] In addition, the method of forming the outer periphery of the mesh material into a bag shape has the problem that the knitting process becomes complicated, making the cost of the mesh material very high, and because the bag-shaped portion must be fitted into one end of the back frame from one end, the structure of the back frame is limited and it lacks versatility.

[0011] The present invention was made to improve this current situation, and its main purpose is to realize a design-oriented form for a backrest made of flexible sheet material such as mesh material by taking advantage of the properties of the sheet material. [Means for solving the problem]

[0012] The present invention can be developed in various ways, and typical configurations are specified in the claims.

[0013] The invention of claim 1 is "It has a seat and a backrest placed behind it, and the backrest has a back frame with left and right side members that are vertically long and open at the front and back, and a flexible sheet material that overlaps the back frame from the front." This is the basic configuration.

[0014] In the above basic configuration, "The side members of the back frame have an inward ridge that protrudes inward in the left-right direction, an outward ridge that protrudes outward in the left-right direction, and a rearward ridge that protrudes rearward, and the area between the inward ridge and the rearward ridge is an inner surface, and the area between the outward ridge and the rearward ridge is an outer surface, The left and right side portions of the sheet material are rolled rearward and extend along the outer surface and rearward-facing ridge of the side member to the inner surface, and the portion of the sheet material located on the inner surface of the side member is covered from behind by a side cover that is separate from the backrest. The structure is as follows.

[0015] The invention of claim 2 has the same basic structure as claim 1, "The side members of the back frame are formed in a mountain shape in plan cross section with a rearward-facing ridge line, and the portions on the left and right outer sides of the rearward-facing ridge line have inclined outer surfaces, while the left and right side portions of the sheet material are rolled up to the inner surfaces of the side members via the inclined outer surfaces and the rearward-facing ridge line, and the portions of the sheet material located on the inner surfaces of the side members are covered with side covers, Since the outer surface of the side member is inclined, the portion of the sheet material that overlaps the outer surface of the side member is exposed to the rear side so as to be visible to people when viewed from behind. hand, The portion of the seat material that is wrapped around the inner surface of the side member is covered from behind by a side cover that is separate from the backrest. " The structure is as follows.

[0016] The invention of claim 3 is the same as claim 1 or 2, The structure is such that "the inner surface of the side member of the back frame is formed with a locking portion that can temporarily hold the sheet material before it is fixed."

[0017] The invention of claim 4 is the same as claim 1 or 2, The upper part of the back frame is made up of an upper member that is continuous with the upper ends of the left and right side members, The upper member has an upper outer surface that is continuous with the outer surface of the side member and an upper inner surface that is continuous with the inner surface of the side member, and the upper part of the sheet material is rolled in from the upper outer surface to the upper inner surface, and the portion of the sheet material that overlaps the upper outer surface of the upper member is exposed, and the portion that is located on the upper inner surface of the upper member is covered with an upper cover. The structure is as follows. [Effects of the Invention]

[0018] In the present invention, the side members of the back frame have a generally triangular shape with a front surface, an outer surface, and an inner surface, but because the entire frame is covered with a sheet material and a cover, the bare surface of the side members is not exposed and cannot be seen. In addition, because the outer surface is also covered with a sheet material, the state in which the outer surface is covered with the sheet material can be clearly seen in a rear view of the chair.

[0019] In other words, the state in which the side members are wrapped around the rear by the seat material is clearly visible when viewed from behind. This creates a design effect that emphasizes the seat material and gives a fresh impression compared to conventional chairs, where the back frame is largely exposed when viewed from behind. In addition, because the inside surfaces of the side members are covered from behind with side covers, it is possible to conceal the edges of the seat material, and the side covers also have an accent effect, demonstrating a high level of design that does not feel strange to the user.

[0020] In addition, in the case of Patent Document 1, the mesh material (sheet material) When installing the mesh material, first Attach it to one of the side members. Then, Because the mesh material must be pulled tight before the other edge material is fitted into the groove of the other side member, there is a problem that the tension in the mesh material loosens slightly after the left and right edge materials are fitted into the grooves of the left and right side members.However, with the present invention, the sheet material can be fixed to the inside surface of the side member while maintaining a constant tension, so the sheet material will not loosen after installation.

[0021] Therefore, the present invention maintains the advantage of being able to easily attach the sheet material in a stretched state, while improving the aesthetic appearance by covering the attachment portion of the sheet material with a side cover. As mentioned above, the side cover has an accent effect, ensuring a high aesthetic appearance not seen in conventional products.

[0022] Various methods can be adopted for attaching the sheet material, but if welding or fastening is used as in claim 1, edging materials as in Patent Document 1 are not required, which reduces costs.

[0023] Now, welding of sheet material is done by pressing the tip face of the horn against the sheet material, and fixing work using fasteners such as a tacker is done by placing the tip of a driving tool loaded with the fastener against the sheet material to drive the fastener out, so in either case, tools must be used.

[0024] In this case, the tool is applied to the inner surface of the side member from the direction perpendicular to the inner surface. However, since the tool has a certain size, if the perpendicular to the inner surface is parallel to the front of the backrest, when fixing to one side member, the tool may come into contact with the other side member. to In particular, when the fixing work is performed using an automated machine, the space required for the tools becomes considerably large, making it difficult to fix the sheet material.

[0025] In contrast, if the perpendicular line of the first surface to which the sheet material is fixed is inclined inward toward the rear in plan view, as in the embodiment, even if the tool for welding or fastening is large, it can be positioned so as not to interfere with the spine frame, which has the advantage that the welding or fastening process can be carried out without any problems. Therefore, it is particularly useful when the sheet material is fixed using an automated machine.

[0026] Furthermore, when the outer surface and the second surface intersect at an acute angle as in the embodiment, the sheet material is folded back significantly at the connection between the outer surface and the second surface, providing strong resistance to tension acting on the sheet material, thereby further suppressing tension acting on the fixing portion of the sheet material and significantly contributing to improving the support strength of the sheet material.

[0027] As described above, in the present invention, the sheet material can be held in a taut state with a predetermined tension while the fixing work is being performed. However, if the configuration of claim 3 is adopted, the entire sheet material can be held in a taut state while the fixing work is being performed, so the fixing work can be performed without manual work. in Whether the fixing work is done manually or using an automatic machine, the fixing work can be done reliably and easily.

[0028] Furthermore, if the side members and upper members are configured so that their surfaces are continuous, as in claim 4, the sheet material is continuous on the outer surfaces of the side members and the upper outer surfaces of the upper members, resulting in a unified overall appearance, which is particularly advantageous in terms of improving aesthetics. [Brief explanation of the drawings]

[0029] [Figure 1] 1A and 1B are diagrams showing an embodiment, in which (A) is a front view, (B) is a perspective view seen from the front, and (C) is a perspective view seen from the rear. [Figure 2] 1A is a rear view, FIG. 1B is a side view, FIG. 1C is a perspective view of the upper cover and the side cover separated, and FIG. 1D is a perspective view of the upper cover and the side cover in contact with each other. [Figure 3] FIG. [Figure 4] FIG. [Figure 5] 1A is a perspective view of the back frame and the auxiliary frame separated from each other, and FIG. 1B is a perspective view of the back frame and the tilting frame separated from each other. [Figure 6] (A) is a front view of the lower part of the back frame, and (B) is a separated view with the tilting frame facing forward and the back frame facing backward. [Figure 7] 10A and 10B are perspective views showing the connection between the back frame and the tilting frame, where (A) is a view from the rear, and (B) is a view from the front with the positions of the frames reversed. [Figure 8] 1A is a perspective view of the tilting frame and the back cover separated from each other, FIG. 1B is a perspective view of the back cover, and FIG. 1C is a partial perspective view of the tilting frame as seen from the front. [Figure 9] 1A is a perspective view of the tilting frame and the armrest as seen from the front, and FIG. 1B is a perspective view of the tilting frame and the armrest as seen from the side. [Figure 10] (A) is a partially cutaway front view of the spine frame, and (B) is a partially cutaway rear view of the spine frame. [Figure 11](A) is a separated perspective view of the back frame and the side cover, (B) is a perspective view of the lower part of the side cover, and (C) is a partial perspective view of the tilting frame seen from the front. [Figure 12] (A) is a partial perspective view of the back frame seen from the rear, and (B) is a sectional view taken along the line XIIB-XIIB of FIG. 4. [Figure 13] It is a sectional view taken along the line XIII-XIII of FIG. 4. (A) is a view in a state where the side cover is omitted, and (B) is a view in a state where the side cover is attached. [Figure 14] It is a sectional view taken along the line XIV-XIV of FIG. 4. (A) is a view in a state where the upper cover is omitted, and (B) is a view in a state where the upper cover is attached. [Figure 15] It is a longitudinal side view of the central part of the back frame and is a sectional view taken along the line XV-XV of FIG. 6(B). [Figure 16] (A) is a sectional view taken along the line XVIA-XVIA of FIG. 6(B), and (B) is a sectional view taken along the line XVIB-XVIB of FIG. 6(B).

Embodiments for Carrying Out the Invention

[0030] Next, embodiments of the present invention will be described based on the drawings. In the following description, the terms "front and rear" and "left and right" are used to specify directions, but these terms of front and rear and left and right are based on a seated person. The front view direction is the direction facing the seated person. Therefore, the left and right in the front view are opposite to the left and right seen from the seated person.

[0031] (1). Outline of the Chair First, the outline of the chair will be described mainly with reference to FIGS. 1 to 4. This embodiment is applied to a swivel chair frequently used for office work or the like. The chair includes a leg device 1 having a leg support column made of a gas cylinder, a base 2 fixed to the upper end of the leg support column, a seat 3 disposed on the base 2, and a backrest 4 on which a seated person can lean.

[0032] For example, as shown in Figure 3, a tilting frame 5 having left and right arms 5a is connected to the base 2 so as to be able to tilt backward. Also, as shown in Figure 2(B), a seat support body 6 to which a seat 3 is fixed is connected to the base 2 so as to be able to move backward, and the seat support body 6 is connected to the arms 5a of the tilting frame 5 so as to be able to rotate relative to the seat support body 6. Therefore, the seat 3 tilts backward slightly while moving backward in conjunction with the backrest 4.

[0033] The seat 3 has a structure in which a cushion is placed on the upper surface of a resin seat inner shell and covered with a skin material, and the seat inner shell is fixed to the seat support body 6 directly or via a seat outer shell.

[0034] As can be seen from Fig. 1, the tilting frame 5 has left and right back support columns 7 that curve upward in an arch shape, and the back support columns 7 and base 8 are smoothly connected so as to curve upward when viewed from the front (and rear). The tilting frame 5 has an inward ridge 9, an outward ridge 10, and a rearward ridge 11, and roughly forms a triangular cross-section. Therefore, the tilting frame 5 has a front surface 12 shown in Fig. 3 and an inclined outer peripheral surface 14 and an inclined inner peripheral surface 13 shown in Fig. 1(C), and the inclined outer peripheral surface 14 and the inclined inner peripheral surface 13 intersect in a mountain shape to reach the rearward ridge 11.

[0035] Furthermore, the portion of the tilting frame 5 consisting of the base 8 and the back support 7 tapers toward both the left and right ends. Therefore, the inclined outer peripheral surface 14 and the inclined inner peripheral surface 13 are widest in the middle portion and narrow toward both the left and right ends. As shown in Figures 2(A) and 4, an optional armrest 15 can be attached to the outer surface of the back support 7. When the armrest 15 is not attached, the outer surface of the back support 7 is covered with a back cover 16.

[0036] For example, as shown in Figure 3, the backrest 4 comprises a back frame 17 that is open at the front and rear and a sheet material (mesh material) 18 stretched over the front surface of the back frame 17. As shown in Figure 3, the back frame 17 is made up of left and right side members 19 that are vertically long, an upper member 20 that is horizontally long, and a lower member 21 that overlaps the front surface of the base 8 of the tilting frame 5 and the back support 7. The lower member 21 is curved upward in an arch shape to match the shape of the tilting frame 5. Each of the members 19, 20, and 21 is made of synthetic resin. The tilting frame 5 is made of aluminum die-cast, but it can also be made of synthetic resin.

[0037] The side members 19 of the back frame 17 are provided with an inward ridge line 23 that protrudes inward in the left-right direction, an outward ridge line 24 that protrudes outward in the left-right direction, and a rearward ridge line 25 that protrudes rearward between the inward ridge line 23 and the outward ridge line 24. Therefore, the area between the inward ridge line 23 and the outward ridge line 24 forms a front surface 26, the area between the outward ridge line 24 and the rearward ridge line 25 forms an outer surface (outer peripheral surface) 27, and the area between the rearward ridge line 25 and the inward ridge line 23 forms an inner surface (inner peripheral surface) 28, with the outer surface 27 and the inner surface 28 inclined in opposite directions.

[0038] 1, the ridges 23, 24, 25 and faces 26, 27, 28 of the side member 19 are continuous with the upper member 20. That is, the front face 26 of the side member 19 is continuous with the front face 26a of the upper member 20, the outer face 27 of the side member 19 is continuous with the upper outer face 27a of the upper member 20, and the inner face 28 of the side member 19 is continuous with the upper inner face 28' of the upper member 20.

[0039] On the other hand, with respect to the lower member 21, the ridges 23, 24, and 25 of the side member 19 are continuous with the ridges of the tilting frame 5, so that the ridges 23b, 24b, and 25b and faces 26b, 27b, and 28b of the lower member 21 are stepped down from those of the side member 19. The lower portion of the lower member 21 forms a cutout 21a, and an auxiliary frame 29 is connected to this cutout 21a.

[0040] Furthermore, the front surface 26b of the lower member 21 is continuous with the front surface 26 of the side member 19, but the lower member 21 does not have any surfaces corresponding to the outer surface 27 and inner surface 28 of the side member 19, and has a rear surface 28c (see Figure 6(C)) that is stepped down from the outer surface 27 and inner surface 28 of the side member 19.

[0041] The sheet material 18 is fixed directly to the side members 19, the upper member 20 and the upper part of the lower member 21 by ultrasonic welding, but at the location of the lower member 21, the sheet material 18 is fixed to an auxiliary frame 29 and is attached to the lower member 21 via the auxiliary frame 29.

[0042] In Figures 1, 2(A), and 3, the sheet material 18 is shown with dotted parallel diagonal lines, and the front surface of the spine frame 17 is shown as is, but in reality, the front surface of the spine frame 17 is hidden by the sheet material 18 and cannot be seen (depending on the type of sheet material 18, it may be slightly visible through it).

[0043] (2) Connection structure between the back frame and the tilting frame Next, a description will be given of the connection structure between the back frame 17 and the tilting frame 5. The drawings will be mainly referred to in FIGS.

[0044] For example, as shown in Figure 5, a main recess 31 that opens forward is formed in the front surface 12 of the base 8 of the tilting frame 5, and a number of reinforcing ribs 32 extending vertically and horizontally are formed inside the main recess 31. Also, a center recess 33 for attaching the rear end of a locking gas cylinder 33a (slightly visible in Figures 2(A) and (B)) is formed in the left-right intermediate portion of the base 8 (the left-right intermediate portion of the main recess 31). The center recess 33 is surrounded by ribs.

[0045] As also shown in Figure 5, a pair of left and right positioning protrusions 34 are provided on the lower member 21 of the back frame 17 so as to protrude rearward, while a positioning hole 35 (see also Figure 16(A)) into which the positioning protrusions 34 fit from the front is formed in the base 8 of the tilting frame 5. The positioning hole 35 is surrounded by a rib. The positioning protrusion 34 has a fairly large protrusion dimension, and fits into the positioning hole 35 with almost no clearance, so that the back frame 17 is attached to the tilting frame 5 in a state where it can firmly support the rearward load.

[0046] 7, for example, side recesses 36 that open toward the front and upward are formed at the upper end of the back support pillar 7 of the tilting frame 5, while side protrusions 37 that fit snugly into the side recesses 36 are formed at the left and right upper end of the lower member 21 of the back frame 17, and the side protrusions 37 and the side recesses 36 are fastened together with bolts 38 and nuts 39. The positioning protrusions 34 are inclined in substantially the same direction as the axial direction O3 of the back support pillar 7 (see FIG. 2(B)).

[0047] The side recess 36 and the side protrusion 37 are formed in the shape of a truncated pyramid, and the side protrusion 37 has a horizontal pocket hole 40 in which the nut 39 is held non-rotatably, while the bottom plate of the side recess 36 has a bolt insertion hole 41.

[0048] As can be seen from Figure 5, the lower part of the side recess 36 of the back support part 7 of the tilting frame 5 is a back recess 42 that opens backward, and the bolt 38 is inserted from the auxiliary recess 42a that is continuous with the back recess 42 to the bottom plate of the side recess 36.

[0049] The back frame 17 is fixed by the engagement of the positioning projection 34 and the positioning hole 35. Tilting frame 5 Because the back frame 17 is positioned, it is firmly fixed to the tilting frame 5 even when fastened with only two bolts 38, one on the left and one on the right. In addition, because the side protrusion 37 and the side recess 36 are shaped like a truncated triangular pyramid, when the bolt 38 is tightened, the side protrusion 37 tightly fits into the side recess 36. As a result, the back frame 17 is firmly fixed to the tilting frame 5 by the two bolts 38 without any rattle.

[0050] (3) Armrest and back cover mounting structure The tilting frame 5 is formed with side recesses 36 that open forward and back recesses 42 that open backward, so when the base 8 and back support 7 of the tilting frame 5 are viewed as a whole, the back recess 42 that opens backward is present between the side recesses 36 that open forward and the main recess 31.

[0051] 8(A) and 9(B), the back recess 42 is generally rectangular and tapered so that the cross-sectional area decreases toward the bottom, and a slight step 43 is formed at the opening edge. The step 43 extends downward from the back recess 42.

[0052] 1 and 2, the armrest 15 is shown with a fixed armrest 15a and a movable armrest 15b overlapping each other. In reality, only one of them is attached. FIG. 9 shows the fixed armrest 15a, and a truncated quadrangular pyramid-shaped positioning boss 45 is formed at the base of the fixed armrest 15a, which fits into the back recess 42 of the tilting frame 5. The armrest base 15a is fastened to the tilting frame 5 with a bolt 46 inserted through the positioning boss 45 from the outside. Therefore, a tapped hole 47 into which the bolt 46 screws is formed at the bottom of the back recess 42 of the tilting frame 5.

[0053] As shown in Figure 9(B), the base of the fixed armrest 15a is formed with a countersunk hole 48 in which the head of the bolt 46 is hidden. The fixed armrest 15a is also integrally formed with a flange plate 49 that overlaps with a step 43 on the outer periphery of the back support 7. The movable armrest 15b has a base body fixed to the back support 7, an intermediate arm attached to the base body so that it can rotate up and down and rotate horizontally, and an armrest attached to the tip of the intermediate arm so that it can rotate horizontally. The base of the base body is similar to the base of the fixed armrest 15a. of The armrest 15a is fixed to the back support 7 with the same bolt 46 as the fixed armrest 15a.

[0054] As described above, when the armrest 15 is not attached to the tilting frame 5, the back recess 42 is covered with the back cover 16. The back cover 16 is adapted to fit into the step portion 43 of the tilting frame 5, and is attached to the tilting frame 5 by an upward-facing first engagement claw 50, a pair of second engagement claws 51 that fit into the back recess 42 of the back support portion 7, and two third engagement claws 52 that protrude forward below the back recess 42.

[0055] Therefore, a pair of first engagement holes 53 into which the first engagement claws 50 fit and engage are formed at the upper end of the back support column 7, a second engagement hole 54 into which the second engagement claws 51 engage after elastic deformation is formed inside the back recess 42 of the back support column 7, and a pair of third engagement holes 55 into which the third engagement claws 42 engage after elastic deformation are formed below the back recess 42. The third engagement holes 55 are formed in the step portion 43.

[0056] The first engagement hole 53 is bag-shaped and opens only rearward, and the first engagement claw 50 engages with the first engagement hole 53 by sliding it upward. Therefore, the upper end of the back cover 16 is held so that it cannot slide upward or be raised backward. On the other hand, the second engagement hole 54 and the third engagement hole 55 open to the front and back. The pair of second engagement claws 51 have hooks with different orientations, and they elastically deform and fall in different directions. Therefore, they are highly effective at preventing slippage. The hooks of the pair of third engagement claws 52 face the same direction.

[0057] Additionally, an auxiliary protrusion 56 that fits into the third engagement hole 55 is provided below the third engagement claw 52 and protrudes forward. Therefore, the back cover 16 is held immovable upward by the first engagement claw 50, and is held immovable downward by the auxiliary protrusion 56. Therefore, the back cover 16 is securely attached without any rattle. Furthermore, the back cover 16 is fitted into the step portion 43 of the tilting frame 5, and the surface of the back cover 16 and the inclined outer peripheral surface 14 of the tilting frame 5 are flush with each other, which not only provides an aesthetically pleasing appearance but also makes it difficult to lift up.

[0058] In this embodiment, the back frame 17 is fastened to the tilting frame 5 with bolts 38, utilizing the back recesses 42 for attaching the armrests 15. That is, the back recesses 42 for attaching the armrests 15 are used as spaces for arranging the bolts 38 for fixing the back frame 17. Therefore, the heads of the bolts 38 are not exposed, which provides an excellent aesthetic appearance.

[0059] (4) Back frame and sheet material Next, the structure of the back frame 17 and the attachment structure of the sheet material 18 will be described, mainly with reference to FIGS.

[0060] As already mentioned, the side members 19 and upper members 20 in the back frame 17 have three ridges 23-25 ​​and three faces 26-28 that are continuous with each other. Therefore, as shown in Figures 12-14, the side members 19 and upper members 20 have rearward-facing ridges 25 and have triangular cross-sectional shapes, but both members have multiple recesses 59 formed in their front faces 26, 26a to reduce weight (this can also be seen as long grooves formed in the front faces 26, 26a and ribs arranged in the long grooves. In any case, the front faces 26, 26a are not flat surfaces).

[0061] 12 and 13, the outer surface 27 of the side member 19 is gently curved and bulges outward. In addition, a V-shaped longitudinal groove 60 is formed in the edge of the front surface 26 of the side member 19 close to the outward ridge 24, and a buffer edge 60a is disposed in the longitudinal groove 60.

[0062] 12(B) and 13, the inner surface 28 of the side member 19 has a second surface 28a that is rounded and intersects with the outer surface 27 in a generally V-shape (at an acute angle) in a plan view, and a first surface 28b that intersects with the first surface 28a in a dogleg-like shape (at an obtuse angle), and the sheet material 18 is fixed to the first surface 28b by welding (the welded portion is indicated by reference numeral 65). As clearly shown in Fig. 12(B), a perpendicular line O1 to the first surface 28b of the inner surface 28 is inclined obliquely inward so as to face rearward and fall toward the inside of the back frame 17 in a plan view.

[0063] 11(A) and 12(A), for example, a number of hooks 63 are formed at appropriate intervals above and below on the inner surface 28 of the side member 19 as an example of a fastening portion for temporarily fastening the sheet material 18 before it is put on. Therefore, temporary fastening holes 64 into which the hooks 63 fit are formed intermittently in the circumferential direction on the long side edge of the sheet material 18.

[0064] The hook 63 has a hollow gate shape in side view. As can be clearly seen in Fig. 13, a relief groove 63a is formed on the inside of the hook 63 due to the use of a slide mold to mold the hook 63. The protrusion 62 forms a bridge portion 62a at the location of the relief groove 63a.

[0065] At the side member 19, the sheet material 18 is wrapped around from the front surface 26, through the outer surface 27, and onto the inner surface 28, with the leading edge reaching close to the protrusion 62. The sheet material 18 is fixed to the first surface 28b at both the upper and lower portions of the hook 63 by ultrasonic welding.

[0066] In this embodiment, sheet material 18 is welded to spine frame 17 by an automatic machine. The automatic machine includes a drive unit that reciprocates horn 66 shown in Fig. 12(B) and a receiving stand (jig, anvil) that securely holds spine frame 17. For example, by moving horn 66 forward and backward while horizontally moving and rotating the receiving stand, each welded portion 65 is formed in order.

[0067] In this case, since the drive unit to which the horn 66 is attached has a certain size, if the perpendicular line O1 of the first surface 28b on the inner surface 28 is parallel to the front surface of the backrest 4, there is a risk that during the welding process to one side member 19, the drive unit will hit the other side member 19, making it impossible to perform the welding.

[0068] In contrast, in this embodiment, when the perpendicular line O1 of the first surface 28b faces rearward and inclined diagonally inward, even if the drive unit is large, the drive unit can be prevented from hitting the back frame 17, and the sheet material 18 can be welded to the side member 19. Furthermore, because the sheet material 18 is folded back significantly at the joint between the outer surface 27 and the second surface 28a, the tension acting on the sheet material 18 is significantly reduced from being transmitted to the welded portion 65. Therefore, the support strength of the sheet material 18 can be significantly improved.

[0069] The same is true for the upper member 20, where, as shown in Figures 12(A) and 14, a large number of hooks 63 are formed on the upper inner surface 28' of the upper member 20, and the sheet material 18 is welded to the upper member 20 between adjacent hooks 63. If the perpendicular line to the first mesh material 28b', which is the welding surface, is taken as O2, the perpendicular line O2 faces backward and inclined diagonally inward in side view, so welding to the upper member 20 can be performed while preventing the drive part of the automatic machine from hitting the lower member 21.

[0070] Also, in the upper member 20, the upper inner surface 28' has a first surface 2ba' and a second surface 28a' that intersect in a V-shape (obtuse angle), and the second surface 28a' intersects with the upper outer surface 27a in a generally V-shape that forms an acute angle while being rounded. Therefore, the tension acting on the sheet material 18 can be significantly suppressed from acting on the welded portion 65.

[0071] (5) Side covers and upper covers The inner surface 28 of the side member 19 is covered by a vertically elongated side cover 70, and the upper inner surface 28' of the upper member 20 is covered from below by an upper cover 71. Therefore, the edges and welded portions 65 of the sheet material 18 are also covered by the covers 70, 71.

[0072] 2(D), the side cover 70 and the upper cover 71 are continuous, while the side cover 70 and the inclined inner peripheral surface 13 of the tilting frame 5 are continuous, as shown in FIG. 1(C), for example. Therefore, although there are seams, the four surfaces of the inclined inner peripheral surface 13 of the tilting frame 5, the left and right side covers 70, and the upper cover 71 form a looped inner peripheral surface that is flush with the entire surface. This provides an excellent aesthetic effect.

[0073] The covers 70, 71 are basically attached by engaging (hooking) forward-protruding engagement claws 72 with engagement step portions 73 formed on the side member 19 and upper member 20, as shown in Figures 11(A), 13(B), and 14(B).

[0074] In this case, the hook 63 is formed in a hollow gate shape, and the engagement step 73 is formed at the hook 63, so that the engagement claw 72 is inserted into the hook 63. This has the advantage that the engagement claw 72 is positioned by the hook 63. Furthermore, the engagement claw 72 is inserted into the engagement step 73 through a temporary fastening hole 64 formed in the sheet material 18. Therefore, there is no need to machine a hole in the sheet material 18 to allow the engagement claw 72 to escape.

[0075] As described above, when injection molding is performed using a metal mold, the hook 63 is formed using a slide mold, and the engaging step 73 is also formed using a slide mold. Therefore, the temporary fastening means for the sheet material 18 and the attachment means for the covers 70 and 71 can be easily formed.

[0076] 11(A), 12(B), and 14(B), for example, forward-facing inclined ribs 74 are provided on the side cover 70 and the upper cover 71 at the locations of the respective engaging claws 72, thereby forming V-shaped engaging portions 75 that sandwich the bridge portions 62a of the protrusions on the side member 19 and the upper member 20. Therefore, even if a person places their fingertips on the inner edges of the covers 70, 71 and pulls them backward, the covers 70, 71 will not be turned up.

[0077] 11(B) and (C), a downward piece 76 is provided on the inner surface of the lower end of the side cover 70, and this downward piece 76 is fitted from above into a gap 77 formed between the upper end of the back support column 7 and the back frame 17 (see arrow 76a in FIGS. 11(B) and (C)). Therefore, the lower end of the side cover 70 is held inward and cannot be separated.

[0078] 2(C)(D) and 4, an inward-facing portion 70a is formed at the upper end of the side cover 70, and a stepped-down portion 78 provided at the tip of the inward-facing portion 70a overlaps from below with stepped-up portions 79 formed at both left and right ends of the upper cover 71. This increases the unity between the side cover 70 and the upper cover 71, and holds the upper cover 71 in a downward, inseparable state.

[0079] Furthermore, the upper ends of the side covers 70 are held so as not to shift inward due to the overlapping of the stepped-up portions 79 and the stepped-down portions 78. Therefore, the side covers 70 are held so as not to separate in any of the front-rear, left-right, or up-down directions, and as a result, the upper covers 71 are also held so as not to separate in any of the front-rear, left-right, or up-down directions.

[0080] Optional items such as a headrest and a hanger can be attached to the upper member 20. These optional items are fixed to the upper member 20 with screws, and the optional items have flange plates of the same shape as the upper cover 20, so that the upper inner surface 28' of the upper member 20 is covered by the optional items with flange plates. Therefore, the aesthetic appearance is not impaired.

[0081] (6) Auxiliary frame Next, the auxiliary frame 29 will be described with reference to Figures 5, 6, 15 and 16.

[0082] 5, auxiliary frame 29 is narrow in the left-right middle portion and widens toward both left and right ends, with a curved, concave top surface. A horizontally oriented support shaft 80 is formed via a bracket piece on lower member 21 at a position outside positioning protrusion 34 in the left-right direction, while auxiliary frame 29 is formed with a catch 81 that engages with support shaft 80 from the front against elastic force. Therefore, auxiliary frame 29 is rotatable about the axis of support shaft 80.

[0083] A pair of left and right engagement holes 82 are formed in a downward-opening state at the lower end of the tilting frame 5 in a region sandwiched between the positioning protrusions 34, while engagement claws 83 are provided on the auxiliary frame 29 so as to protrude upward and fit unslip into the engagement holes 82. The engagement claws 83 are U-shaped in plan view.

[0084] With auxiliary frame 29 in a generally horizontal position, catch 81 can be fitted onto support shaft 80 from below as shown by arrow 84 in Fig. 5(A). Next, when auxiliary frame 29 is rotated downward as shown by arrow 85 in Fig. 5(B), engaging claw 83 is elastically deformed and fits into engaging hole 82 from the front as shown by arrow 86 in Fig. 5(A). This maintains the position of auxiliary frame 29.

[0085] Furthermore, in this embodiment, as shown in Figure 16(B), a pair of left and right stopper protrusions 87 are provided on the auxiliary frame 29 protruding rearward, and these stopper protrusions 87 are fitted from the front into forward-facing stopper holes 88 formed by ribs on the base 8 of the tilting frame 5.

[0086] The lower part of the sheet material 18 is fixed in advance to the rear surface of the auxiliary frame 29 by welding or a stapler. Then, in the welding process of the sheet material 18, the auxiliary frame 29 is connected to the support shaft 80 and rotated toward the front, and the peripheral part of the sheet material 18 is engaged with the group of hooks 63. Once the sheet material 18 has been temporarily fastened to the hooks 63, the auxiliary frame 29 is rotated backward to fit the engaging claws 83 into the engaging holes 82. This holds the sheet material 18 in a taut state on the spine frame 17. Therefore, the sheet material 18 is welded to the spine frame 17 in a taut state.

[0087] The backrest 4, with the seat material 18 fixed to the back frame 17, is fixed to the tilting frame 5 with bolts 38, but if the auxiliary frame 29 is held in position on the back frame 17 only by the engaging claws, when a large tension is applied to the seat material 18 due to a seat occupant leaning back, the auxiliary frame 29 may rotate back and loosen the seat material 18. Therefore, in the past, the auxiliary frame 29 was fixed to the tilting frame 5 with screws.

[0088] In contrast, in this embodiment, the auxiliary frame 29 cannot be separated from the lower member 21 unless it is rotated around the axis of the support shaft 80. However, since the stopper protrusion 87 is located below the support shaft 80, when the back frame 17 is fixed to the tilting frame 5, the stopper protrusion 87 fits into the stopper hole 88, preventing the auxiliary frame 29 from rotating back due to the weight of the seated person. This can reliably prevent the auxiliary frame 29 from rotating back due to the weight of the seated person without using screws. This can also reduce costs.

[0089] (7) Summary For example, as shown in Figure 1(C), in this embodiment, the outer surfaces 27 of the side members 19 and the upper outer surfaces 27a of the upper members 20 that make up the back frame 17 are covered with sheet material 18, so that the entire backrest 4 appears to be made of sheet material 18, presenting a unique aesthetic appearance.

[0090] Moreover, rather than covering the entire periphery of the side member 19 with the sheet material 18, the inner surface 28 is covered with the side cover 70, which provides an accentuating effect and creates a sharp and sophisticated design. Furthermore, since the sheet material 18 is fixed to the inner surface 28 of the side member 19, it can be easily fixed in a taut state, but since the fixed portion is covered with the side cover 70, there is no problem with aesthetics.

[0091] In other words, the side cover 70 has both the aesthetic effect of adding an accent to the seat material 18 and the aesthetic effect of hiding the fixing portion of the seat material 18. In particular, when the inner surface 28 of the side member 19 is continuous with the inner peripheral surface 13 of the tilting frame 5 as in the embodiment, a loop-shaped inner peripheral surface is formed, which is particularly preferable.

[0092] Furthermore, if the sheet material 18 extending to the lower end of the back frame 17 were visible from behind, it could be too visible and detract from the aesthetic appearance, but in this embodiment, the lower member 21 of the back frame 17 is not visible from behind, and the sheet material 18 is exposed on the outer surfaces 27 of the side members 19 and the upper outer surfaces 27a of the upper member 20, so that the sheet material 18 is only exposed to a moderate extent and is unlikely to give a sense of incongruity to people. In this respect as well, the design exhibits excellent features.

[0093] 12(B) and 13, the side member 19 has three faces 26, 27, and 28 and has a roughly triangular cross-sectional shape, but because the width of the outer face 27 is the widest, the wraparound state of the seat material 18 is emphasized, resulting in an unprecedented and innovative design. In addition, because the front-to-back width of the side member 19 is greater than the left-to-right width, it has excellent strength to support the weight of a seated person without increasing the cross-sectional area.

[0094] The characteristic shape of the welding surface has already been described, but by combining it with the temporary fastening hooks 63, the backrest 4 can be manufactured efficiently and with high quality using an automatic welding device. This is also one of the advantages of this embodiment. The same effect can be obtained even if fastening is performed using a fastener such as a tacker.

[0095] The present invention can be embodied in various ways other than those described above. For example, as a means for temporarily fastening the sheet material 18, it is possible to attach hooks to the outer periphery of the sheet material 18 and form an engagement portion on the spine frame 17 to which the hooks can be hooked. Furthermore, various structures other than welding and fastening can be used as a fastening means. For example, it is possible to fasten a tape-like edge member to the outer periphery of the sheet material and engage this with a hook formed on the spine frame. [Industrial Applicability]

[0096] The present invention can be embodied in a chair, and therefore has industrial applicability. [Explanation of symbols]

[0097] 3 seats 4 Backrest 5 tilting frame 7. Back support of tilting frame 8 Tilt frame base 9 Inward ridge of tilting frame 10 Outward ridge of tilting frame 11 Rearward facing ridge of tilting frame 12 Front of tilting frame 13 Inclined inner surface of tilting frame 14 Inclined outer surface of tilting frame 15 Armrest 16 Back cover 17 Back frame 18 Sheet material (mesh material) 19 Side members 20 Upper Member 21 Lore Member 23 Inward ridge of spine frame 24 Outward ridge of spine frame 25 Back frame rearward ridge 26 Front of side member 27 Outer surface (periphery) of side member 27a Upper outer surface (outer periphery) of upper member 28 Inner surface (inner circumference) of side member 28a,28a′ 2nd side 28b,28b′ 1st ​​page 28' Upper inner surface of upper member (inner circumferential surface, lower surface) 29 Auxiliary Frame 63 Hook as an example of a temporary fastening part 64 Temporary fixing holes for sheet material 65 Welded area 66 Horn 70 Side cover 71 Upper cover O1 Normal to the welding surface of the side member O2 Normal line to the welded surface of the upper member

Claims

1. The seat has a seat and a backrest arranged behind it, and the backrest has a back frame having left and right side members in the vertically long direction and opening in the front and rear, and a flexible sheet material overlapping the back frame from the front, The side members of the back frame have an inward ridge line that protrudes inward in the left-right direction, an outward ridge line that protrudes outward in the left-right direction, and a rearward ridge line that protrudes rearward, and the area between the inward ridge line and the rearward ridge line is an inner surface, and the area between the outward ridge line and the rearward ridge line is an outer surface, The left and right side portions of the seat material are rolled rearward and extend along the outer surface and rearward-facing ridge of the side member to the inner surface, and the portion of the seat material located on the inner surface of the side member is covered from behind by a side cover separate from the backrest. chair.

2. The seat has a seat and a backrest arranged behind it, and the backrest has a back frame having left and right side members in the vertically long direction and opening in the front and rear, and a flexible sheet material overlapping the back frame from the front, The side members of the back frame are formed in a mountain shape in a plan cross section with a rearward ridge line, and the portions on the left and right outer sides of the rearward ridge line have inclined outer surfaces, the left and right side portions of the sheet material are rolled up along the inclined outer surfaces and the rearward-facing ridge lines of the side members to the inner surfaces thereof, and the portions of the sheet material located on the inner surfaces of the side members are covered with side covers, Since the outer surface of the side member is inclined, the portion of the sheet material that overlaps the outer surface of the side member is exposed to the rear side so as to be visible to people in a rear view, The portion of the seat material that is wrapped around the inner surface of the side member is covered from behind by a side cover that is separate from the backrest. chair.

3. A locking portion is formed on the inner surface of the side member of the back frame, which can temporarily hold the sheet material before fixing it. A chair according to claim 1 or 2.

4. The upper part of the back frame is composed of an upper member that is continuous with the upper ends of the left and right side members, The upper member has an upper outer surface continuous with the outer surface of the side member and an upper inner surface continuous with the inner surface of the side member, an upper portion of the sheet material is rolled in from the upper outer surface to the upper inner surface, a portion of the sheet material overlapping the upper outer surface of the upper member is exposed, and a portion located on the upper inner surface of the upper member is covered with an upper cover. A chair according to claim 1 or 2.

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