chair

Abstract

To provide a technique which allows a user to easily replace a backrest of a chair.SOLUTION: A backrest 5 has a back inner shell 21 and a back cushion body 22 stretched on a front surface thereof, and the back inner shell 21 is inseparably held forward on a back outer shell 10 by male catches 62 and 64 to 66 and female catches 63 and 67 to 69. A coupling bracket 76 projects downward to a lower end of the back inner shell 21, and the coupling bracket 76 is fixed to the back outer shell 10 via another bracket 42. Since it is visually seen that the backrest 5 which releases the fixation of the coupling bracket 76 can be detached, a user can easily replace the backrest 5.SELECTED DRAWING: Figure 10

Description

Technical Field

[0001] The present invention relates to a chair having an inner shell. The backrest

Background Art

[0002] Although the seats and backrests of chairs have various structures, a structure in which a cushion body is stacked on an inner shell and the inner shell is fixed to a receiving member such as an outer shell or a back frame is frequently used.

[0003] As an example, in Patent Document 1, as a structure in which a back inner shell (back body) is attached to a back frame having a structure in which left and right support portions are connected by stays (back main body attachment seats), the connection between the lower end portion of the back inner shell and the stay of the back frame is a screw fixation type, and the connection between the support column of the back frame and the back inner shell is a connection by a claw member.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Now, the backrest of a chair may get dirty or the cloth (skin material, upholstery) may wear out, and in such cases, the user may want to replace the backrest. Or, even if it is not damaged, the user may want to change it to a different color.

[0006] ​In these cases, the user would have to remove and replace the backrest, but in the case of Patent Document 1, the structure of Patent Document 1 makes it difficult to see the screws and the claw members are not visible from the outside at all, so it is not clear how to remove the backrest. Consequently, the user would have to either give up on replacing the backrest and continue using the chair, or buy a new chair, which is hardly user-friendly, and in the latter case it would also go against the efficient use of resources.

[0007] The present invention was made against this backdrop, and the user is back- re The aim is to provide chairs that can be easily replaced. [Means for solving the problem]

[0008] The present invention includes various configurations, the typical ones of which are specified in each claim. Of these, the chair according to claim 1 is: " It has a backrest with a back cushion body positioned on the front of the back inner shell, and a back outer shell positioned behind the back inner shell, The back inner shell is held in a position where it cannot move forward relative to the back outer shell by an engaging means that engages when the back inner shell is moved downward while superimposed on the back outer shell. " This is the basic structure.

[0009] And in addition to the basic configuration described above, " A connecting bracket is provided at the lower end of the back inner shell, exposed below the back cushion body, and the connecting bracket is connected to the back outer shell by a rotary or push-type fastener. " This configuration has been added.

[0011] The engagement mechanism involves the fitting or catching of an engaging portion provided on the inner shell and an engaged portion provided on the seating member. The engaging portion and the engaged portion can be in various configurations, such as a combination of an engaging claw and an engaging bar, a combination of an engaging claw and an engaging hole, or a combination of engaging claws. engagement It is preferable to hold the inner shell in a state where it does not move from side to side by means of a mechanism. In other words, it is preferable to have a rattle prevention function in the engaging mechanism.

[0013] Claim 2 The invention is claimed 1 This is an example of the development of the invention, "The engagement means is the BackIt is composed of a group of rear-facing male catches provided in multiple stages on the rear surface of the inner shell and a group of forward-facing female catches provided in multiple stages on the front surface of the back outer shell. It has such a structure.

[0014] centre As fasteners, screws or expandable push rivets can be used. ru.

[0015] Claim 3 The invention of is a realization of Claim 1 or 2 and has a structure of "The coupling bracket is hidden from the front by the seat." It has such a structure.

[0016] Claim 4 The invention of is an expansion example of Claim 3 and has a structure of "The coupling bracket is fastened to the bracket provided on the back outer shell with a fastener." It has such a structure. Claim 5 uses screws as fasteners.

Advantages of the Invention

[0018] Now, as a means for preventing the movement of the backrest or the seat, it may be considered to attach the inner shell to the receiving member only with fasteners such as screws. However, in this case, there are problems such as the time-consuming installation and, in the case of the backrest, the problem that the head of the fastener is exposed on the rear surface, which impairs the aesthetic feeling. Moreover, in the retaining means using the engaging claws that elastically deform, there are problems such as it is not clear from the appearance how to disengage the engaging claws from the receiving member and it is troublesome to move the inner shell while maintaining the state where the engaging claws are disengaged, which is difficult for the user to handle.

[0019] On the contrary, The present invention If the movement prevention means (Connecting brackets and fasteners) is adopted in such a way that it is exposed from the cushion body, Downward since the movement prevention means comes into contact with the user's eyes, the user can RenoIt is natural to try to release the fixing mechanism that prevents movement in order to remove it, and after releasing the fixing mechanism that prevents movement , the backrest Pull it towards you or downwards.

[0020] Then, by the user backrest The direction of movement of the mechanism and the engagement direction of the engagement means coincide, The backrest is the back outer shell. To deviate from it. Therefore, users can perform common-sense tasks that are visually apparent without having to consult the instruction manual. Backrest Outer shell It can be easily removed. backrest After removing it, Backrest and back outer shell By visually inspecting the engagement means provided on the mating surface, the structure of the engagement means can be understood, and new backrest It can be installed.

[0021] Therefore , backrest This makes replacement easier and meets user needs. Furthermore, since there's no need to replace the entire chair, it contributes to the efficient use of resources.

[0022] Engagement means teeth Various structures can be adopted, but 2 This configuration makes it easy to visually identify the combination of the male and female catches, allowing for quick installation.

[0023] The present invention As shown above, by providing an exposed coupling bracket on the lower part of the back cushion as a means of preventing movement, the coupling bracket will always be visible to the user, and the user will know how to remove the backrest. glance This allows for easier monitoring, further improving the ease of replacing the backrest. Also, The present invention When a connecting bracket is provided as described above, 3 By concealing the connecting bracket from the front with the seat, the connecting bracket is not visible from the outside when the chair is in use, making it easy to replace the backrest without compromising aesthetics.

[0024] In the present invention, the connecting bracket may be directly fixed to the back outer shell, but the claim 4 As shown, connecting the bracket to the back outer shell with a fastener prevents the structure of the back outer shell from becoming overly complex. Furthermore, the high degree of design flexibility between the connecting bracket and the bracket on the back outer shell allows for the placement of the connecting bracket in the appropriate position. [Brief explanation of the drawing]

[0027] [Figure 1] These are external views of the chair according to the embodiment, where (A) is a perspective view seen from the front and above, (B) is a perspective view seen from the rear and above, (C) is a perspective view seen from the front and below, and (D) is a perspective view seen from the rear and below. [Figure 2] (A) is a perspective view showing the backrest and seat inner shell separated, (B) is a perspective view showing the seat separated, and (C) is a partial side view. [Figure 3] This is a perspective view showing the inner and outer shells of the seat separated. [Figure 4] (A) is a separate perspective view of the seat outer shell and the rear spring support, (B) is a separate perspective view of the support mechanism, and (C) is a perspective view showing the relationship between the back outer shell and the base. [Figure 5] (A) and (B) are perspective views showing the relationship between the seat outer shell and the base, and (C) is a perspective view primarily of the back inner shell seen from the rear. [Figure 6] (A) is a perspective view showing the lifting mechanism and the tilt locking mechanism, (B) is a separated perspective view showing the relationship between the support mechanism and the back outer shell, and (C) is a perspective view centered on the locking mechanism. [Figure 7] (A) is a longitudinal side view of the left and right middle section of the seat, (B) is a cross-sectional view taken from the VII-VII viewing direction in Figure 3, and (C) is a partial enlargement of (A). [Figure 8] (A) is a separate perspective view showing the installation procedure for the seat inner shell, (B) is a perspective view of the seat inner shell seen from the underside, and (C) is a perspective view of the multi-functional bracket seen from below. [Figure 9](A) is a perspective view with the seat outer shell and back cushion omitted, (B) is a perspective view with the back inner shell separated, and (C) is a partial front view. [Figure 10] (A) is a plan view of the back inner shell, and (B) is a perspective view of the back inner shell separated. [Figure 11] The diagram shows a reference example of a backrest, with (A) being a perspective view, (B) being a partial front view of the back inner shell, and (C) being a perspective view of the back inner shell separated. [Figure 12] (A) is a perspective view with the back inner shell separated, and (B) is a partial perspective view of the back inner shell seen from the reverse side. [Modes for carrying out the invention]

[0028] Next, embodiments of the present invention will be described based on the drawings. In the following description, the terms "front and back" and "left and right" will be used to indicate direction, but these terms are based on the direction a person sitting in a chair in a normal posture is facing. The front view is a view from the direction opposite to the seated person.

[0029] (1) Overview First, let me explain the overview. The chair of this embodiment is a swivel chair commonly used for office work. As shown in Figures 1 and 2, the chair comprises, as its main elements, a leg assembly 1 having a leg support (gas cylinder) 2 and multiple leg wings, a base 3 fixed to the upper end of the leg support 2, a seat 4 positioned above the base 3, and a backrest 5 connected to the base 3 so as to be able to tilt backward. Casters are provided at the tip of each leg wing that makes up the leg assembly 1.

[0030] An armrest 7 is attached to the underside of the base 3, specifically the part in front of the leg support 2, via an armrest bracket 6. Although only one armrest 7 is shown on the left side in the diagram, a pair is installed on both the left and right sides. The armrest 7 is an optional item and may not be installed. If the armrest 7 is not installed, the armrest bracket 6 is also not installed. Therefore, the armrest bracket 6 is a dedicated part for attaching the armrest 7.

[0031] For example, as shown in Figures 2(A) and 2(C), the chair comprises a front seat outer shell 8 and a rear seat outer shell 9 to which the seat 4 is attached from above, and a back outer shell 10 to which the backrest 5 is attached from the front, with the rear seat outer shell 9 and the back outer shell 10 being integrated. ru. Fu The rear end of the front seat outer shell 8 and the front end of the rear seat outer shell 9 are connected by the left and right longitudinal connecting shafts 11 shown in Figure 2(B), allowing for relative rotation (details will be described later).

[0032] As shown in Figures 2(A) and 3, the chair's support mechanism includes a spring (compression coil spring) 12 that expands and contracts in the front-to-back direction as an example of an elastic support means for reclining, and the backrest 5 tilts backward against the spring 12, with the connecting shaft 11 as the pivot point. In addition, the seat outer shells 8 and 9 move forward in conjunction with the backward tilting movement of the backrest 5.

[0033] Furthermore, since the rear seat outer shell 9 is integrated with the back outer shell 10, the rear seat outer shell 9 tilts backward together with the back outer shell 10, but the front seat outer shell 8 only moves forward without tilting backward. Consequently, the front seat outer shell 8 (front of seat 4) and the rear seat outer shell 9 (rear of seat 4) rotate relative to each other in conjunction with the backward tilting of the backrest 5.

[0034] As shown in Figures 2(A) and 3, the synthetic resin seat inner shell 13 that constitutes the seat 4 is connected by a flexible hinge portion 14 to a front portion 13a that overlaps the front seat outer shell 8 and a rear portion 13b that overlaps the rear seat outer shell 9, thereby allowing relative rotation between the front seat outer shell 8 and the rear seat outer shell 9. Therefore, when the backrest 5 is reclined (rocked), the seat 4 as a whole moves forward while bending with the hinge portion 14 as the pivot point.

[0035] The front portion 13a of the seat inner shell 13 is attached to the front seat outer shell 8, and the rear portion 13b is attached to the rear seat outer shell 9. As shown in Figure 1, an optional hanger 15 can be attached to the upper end of the back outer shell 10.

[0036] (2) Details of the support mechanism Next, we will explain the details of each part. First, we will explain the support mechanism centered on the base 3. For example, as shown in Figures 3, 4(B)(C), and 6(B), the base 3 is made of sheet metal and has an upward-opening box shape with a bottom plate and left and right side plates 3a, and is long in the front-to-back direction. As shown in Figures 6(B) and 7(A), a bush 19 is fixed inside the base 3 via a U-shaped reinforcing bracket 18, and the upper end of the leg support 2 is fitted into the bush 19 from below. As shown in Figures 3, 4(B)(C), etc., the upper ends of the left and right side plates 3a that make up the base 3 are provided with left and right outward-facing side flanges 3b that are long in the front-to-back direction.

[0037] As shown in Figure 7(A), the seat 4 mainly consists of the resin seat inner shell (seat plate) 13 mentioned earlier and the seat cushion body 20 placed on top of it, and the seat cushion body 20 is covered with a surface material such as cloth or leather. For example, as shown in Figure 8(B), the hinge portion 14 of the seat 4 is composed of many U-shaped connecting pieces that curve downward, and there are slits between adjacent connecting pieces.

[0038] For example, as schematically shown in Figure 2(A), the backrest 5 mainly consists of a synthetic resin back inner shell (back panel) 21 and a back cushion body 22 positioned in front of it, the back cushion body 22 being covered with a surface material such as cloth. The back inner shell 21 is attached to the back outer shell 10 described above.

[0039] As previously described, the rear seat outer shell 9 is integrally formed with the lower end of the back outer shell 10, but as shown in Figure 6(B), for example, the rear seat outer shell 9 is separated on both the left and right sides of the base 3. Therefore, the rear seat outer shell 9 is bifurcated.

[0040] Furthermore, the aforementioned connecting shaft 11 is stretched across bearing portions provided at the front ends of the left and right rear seat outer shells 9 via bearings, while as shown in Figures 4(A) and 4(B), a plurality of downward-facing ribs 23 are provided at the rear end of the front seat outer shell 8, arranged on the left and right, and projecting downwards. A sheet metal rear spring support 24, which is U-shaped in plan view and has left and right rearward-facing side plates 24a, is superimposed on the downward-facing ribs 23 from the front, and the connecting shaft 11 passes through the side plates 24a of the rear spring support 24 and the downward-facing ribs 23 of the front seat outer shell 8.

[0041] Therefore, the front end of the rear seat outer shell 9 and the rear end of the front seat outer shell 8 are connected by a connecting shaft 11 so as to be able to rotate relative to each other. As can be seen from Figure 4(C), the inner parts 9a of the left and right rear seat outer shells 9 overlap the side flanges 3b of the base 3 from below. Therefore, the rear seat outer shell 9 can rotate downwards with the connecting shaft 11 as the pivot point, but it cannot rotate upwards (the backrest 5 does not rotate forwards even when tilted backwards).

[0042] For example, as shown in Figure 4(B), the front end of the spring 12 is held in place by the front spring support 25 to prevent displacement. The front spring support 25 is fitted into a hole provided in the front wall of the base 3.

[0043] For example, as shown in Figures 5(A) and 5(B), the rear end of the base 3 is an overhang 3c that extends diagonally upward, and the left and right longitudinal tilting guide shafts 26 are fixed to the rear end of the overhang 3d such that both ends are exposed to the outside of the base 3, and a resin slider 27 is attached to the exposed part of the tilting guide shaft 26. Meanwhile, as shown in Figure 6(B), for example, an arc-shaped tilting guide groove 28 is formed at the lower end of the back outer shell 10 into which the slider 27 slides freely.

[0044] Therefore, the backrest 5 is guided by the tilting guide groove 28, tilting backward and descending while its lower end moves forward, and the seat 4 moves forward in conjunction with this. As a result, the lower part of the back outer shell 10 is recessed below the seat surface, and when reclining, the lower part of the back outer shell 10 is recessed below the base 3. As shown in Figure 6(B), the front end (lower end) of the tilting guide groove 28 is connected to a relief groove 29 that allows the slider 27 to be fitted when assembling the chair.

[0045] Furthermore, the lower part of the tilting guide groove 28 extends to the rear seat outer shell 9. In other words, the tilting guide groove 28 is formed to span both the rear seat outer shell 9 and the back outer shell 10.

[0046] For example, as shown in Figure 5(B), guide bars 30, which are longitudinal on both sides, are fixed to the upper front end of the base 3 with both ends exposed to the outside of the base 3. On the other hand, as also shown in Figure 5(B), the front seat outer shell 8 is formed in the shape of a rectangular frame in plan view with a rectangular opening, and longitudinal guide grooves 33 are formed on the left and right inner surfaces of the downward-facing wall 32 surrounding the opening 31, into which the guide bars 30 can slide freely. The front seat outer shell 8 has a basic shallow dish shape and has numerous ribs formed inside.

[0047] Therefore, the front seat outer shell 8 moves back and forth supported by the guide bar 30, is held in place by the guide bar 30 so as to be unable to move upward, and also moves back and forth while supported by the connecting shaft 11. In this case, the connecting shaft 11 slides along the upper surface of the side flange 3b of the seat 4, but because the rear seat outer shell 9 is close to the side flange 3b of the base 3 from below, the connecting shaft 11 is held in place so as to be unable to move upward, and the front seat outer shell 8 as a whole is also held in place so as to be unable to move upward.

[0048] As clearly shown in Figure 5(B), a notch 34 is formed at the rear of the guide groove 33 of the front seat outer shell 8, and the notch 34 is closed by a plug 35 that is fitted onto the front seat outer shell 8 from above. This is a measure to enable the assembly of the front seat outer shell 8. During assembly, the guide bar 30 is inserted into the left and right ends of the guide bar 30 through the relief groove 33a formed in the downward-facing wall 32 so as to communicate with the front end of the guide groove 33, and then the notch 34 is closed with the plug 35.

[0049] As shown in Figure 6(B), the mounting material 38 for the lifting mechanism is fixed with screws to the part of the base 3 behind the reinforcing bracket 18, and the right side of the mounting material 38 rotatably holds the pivot shaft portion 39a of the lifting operation lever 39 that pushes the push valve of the leg support column 2. A bearing groove 38a is formed on the right side of the mounting material 38 for fitting the pivot shaft portion 39a of the lifting operation lever 39. As shown in Figure 1(D), the lifting operation lever 39 is exposed outward (to the right) through a hole provided on the lower surface of the base 3.

[0050] As shown in Figures 6(A) and 6(C), the lower end of the tilt lock body 40 is fitted into the mounting material 38 for the lifting mechanism, and the lower end of the tilt lock body 40 is connected to the mounting material 38 for the lifting mechanism by the base end of the tilt operation lever 41. The base end of the tilt operation lever 41 is fitted to the tilt lock body 40 so as not to rotate relative to it, and the tilt lock body 40 rotates when the tilt operation lever 41 is rotated.

[0051] The tilting locking body 40, by rotating, switches between a tilting lock position in which it contacts the multi-functional bracket 42 fixed to the lower inner surface of the back outer shell 10, and a free position in which it does not contact the multi-functional bracket 42 (when the tilting locking body 40 rotates downward, it returns to the free position). Naturally, in the locked position, the backrest 5 is held in a position where it cannot tilt backward, and in the free position, the backrest 5 is held in a position where it can tilt backward freely.

[0052] (3) Mounting structure of the seat inner shell Next, the mounting structure of the seat inner shell 13 will be described. As shown in Figure 8, the lower surface of the front portion 13a of the seat inner shell 13 has a plurality of plate-shaped bosses 44 that rest on the front seat outer shell 8.

[0053] On the other hand, an engaging claw 45, which is hook-shaped (L-shaped) in side view and has a rearward-facing hook portion 45a, is provided projecting downward from the lower surface of the rear end of the rear portion 13b of the seat inner shell 13, while an engaging frame portion 46 is formed in the rear seat outer shell 9 into which the hook portion 45a of the engaging claw 45 is fitted from below. The engaging frame portion 46 has an engaging bar portion 46a into which the hook portion 45a of the engaging claw 45 engages (gets caught), and side frame portions 46b connected to both the left and right ends of the engaging bar portion 46a, forming a U-shape in plan view.

[0054] For example, as shown in Figures 8(A) and 7(B), a guide groove 47 is formed on the front side of the engagement frame portion 46 of the rear seat outer shell 9, which guides the engagement claw 45 to fit into the engagement frame portion 46. Furthermore, as shown in Figure 3, for example, the front seat outer shell 8 has upward-bulging land portions 56 formed in three places on its front side: the left and right middle portions and the left and right side portions, and these land portions 56 are connected to the front seat outer shell 8 by expandable push rivets 48.

[0055] Therefore, a downward-facing boss portion 49 is formed on the front of the inner seat shell 13, while the front outer seat shell 8 has an upward-facing bulge formed on the receiving seat 50, which the downward-facing boss portion 49 abuts against from above, and a cylindrical upward-facing boss portion 51 is formed on the receiving seat 50 into which the downward-facing boss portion 49 fits with almost no gap. Mounting holes 52 are provided in the downward-facing boss portion 49 and the receiving seat 50.

[0056] The expandable push rivet 48 has a flange 53a at its base end and a split outer cylinder 53, and a rod 54 fitted into the outer cylinder 53 from its base end. When the rod 54 is retracted to narrow the outer cylinder 53, the outer cylinder 53 is inserted into the mounting hole 52 from below, and then the rod 54 is pushed in, the outer cylinder 53 expands due to the action of the tapered surface formed at the tip of the rod 54.

[0057] The rod 54 that constitutes the expandable push rivet 48 also has a flange 54a at its base end. When the rod 54 is pushed in, the two flanges 53a and 54a overlap. The flange 54a at the base end of the rod 54 is slightly smaller in diameter than the flange 53a of the outer cylinder 53, and the flange 53a of the outer cylinder 53 has a relief groove 55 formed therein so that a fingernail or the like can be hooked onto the flange 54a of the rod 54. Therefore, when replacing the seat 4, the rod 54 should be retracted and the expandable push rivet 48 should be removed.

[0058] (4) Structure of the back Next, the backrest 5 and the back outer shell 10 will be described. As shown in Figure 10(B), a pair of vertically elongated main ribs 58 are formed on the rear surface of the back inner shell 21, extending vertically over approximately the entire height. As shown in Figure 5(C), the upper part 59a of the reinforcing pipe 59 is inserted from below into a downwardly opening tunnel portion 58a provided at the lower part of the vertically elongated main ribs 58.

[0059] The reinforcing pipe 59 has an upper part 59a that is long in the vertical direction, a lower part 59 that is long in the front-to-back direction, and an inclined part 59c that connects the two. The lower part overlaps the rear seat outer shell 9 from above, and the inclined part 59c mainly overlaps the lower part of the back outer shell 10. It is held in place by a flap 42a provided on the multi-functional bracket 42 so as not to detach from the back outer shell 10 (it may also be held in place by the multi-functional bracket 42). As can be seen from Figure 10(B), the lower part 59b of the reinforcing pipe 59 is located inside the engagement frame part 46.

[0060] As shown in Figure 10(B), the left and right vertically elongated main ribs 58 are connected by a pair of horizontally elongated ribs 60 that are separated vertically, and a cross rib 61 is provided inside the enclosure between the vertically elongated main ribs 58 and the horizontally elongated ribs 60. Also as shown in Figure 10(B), a pair of first male catches 62 are provided on the upper part of the rear surface of the back inner shell 21 and inside the vertically elongated main ribs 58, while a first female catch 63 is provided on the upper part of the back outer shell 10 into which the first male catches 62 fit from above.

[0061] As shown in Figure 10(B), the outer portion of the vertically elongated main rib 58 of the back inner shell 21 has, from top to bottom, a second male catch 64, a third male catch 65, and a fourth male catch 66 projecting backward. On the other hand, the front surface of the back outer shell 10 has a second female catch 67 into which the second male catch 64 fits from above, a third female catch 68 into which the third male catch 65 fits from above, and a fourth female catch 69 into which the fourth male catch 66 fits from above, all projecting forward. Each of the male catches 62, 64-66 and female catches 63, 67-69 is an example of the engagement means described in the claims.

[0062] Each female catch 63, 67-69 has at least its outer surface inclined in a plan view such that the distance between them narrows towards the front. On the other hand, the first male catch 62, the second male catch 64, and the fourth male catch 66 are provided with left and right outward-facing locking flaps 70. As a result, the back inner shell 21 (backrest 5) is held in a position where it cannot move forward at the locations of the first male catch 62, the second male catch 64, and the fourth male catch 66. When the tunnel portion 58a of the back inner shell 21 is fitted from above onto the upper part 59a of the reinforcing pipe 59, the downward movement of the back inner shell 21 causes each male catch 62, 64-66 to engage with the female catches 63, 67-69.

[0063] The multi-functional bracket 42 is made of synthetic resin and, as shown in Figure 6(C), has a base portion 71 fixed to the back outer shell 10 with screws 76b (see the right end of Figure 7(A)), a lock receiving portion 72 protruding downward from the base portion 71 and in contact with the tilting locking body 40, and an enclosure frame portion 73 protruding upward from the base portion 71.

[0064] As can be seen from Figure 6(B), the arc-shaped tilting guide groove 28 is formed on the inner surface of the projection 74 that extends continuously from the lower part of the back outer shell 10 to the rear seat outer shell 9, and the base 71 of the multi-functional bracket 42 is fixed to the top surface of the projection 74 with screws. Therefore, the base 71 of the multi-functional bracket 42 has a screw insertion hole, and the nut 75 shown in Figure 8(C) is attached inside the projection 74.

[0065] As shown in Figure 10(B), the enclosure frame 73 of the multi-functional bracket 42 has left and right side plates 73a and a back plate 73b continuous therewith, and a connecting bracket 76 provided at the lower end of the back inner shell 21 via left and right arm-shaped ribs 76a is fixed to the back plate 73b of the enclosure frame 73 with screws 76b. The connecting bracket 76 is formed to overhang behind the lower rear surface of the back inner shell 21. The bis76b is an example of a fastener.

[0066] When fixing the connecting bracket 76 with screws 76b, tapped holes for screwing the screws 76b may be formed in the back plate 73b of the enclosure frame 73, or nuts may be attached. Alternatively, without using screws 76b, the same procedure as for the seat 4 may be used. , as a zipper It is also possible to use the expandable push rivet 48.

[0067] As clearly shown in Figure 9(C), the connecting bracket 76 of the back inner shell 21 is exposed below the back cushion body 22. Therefore, the screws 76b or expandable push rivets 48 that secure the connecting bracket 76 also have their heads exposed below the back cushion body 22. Thus, when a user replaces the backrest 5, the user can immediately understand that they only need to remove the screws 76b or expandable push rivets 48.

[0068] After removing the screws 76b or the expandable push rivets 48, the user will typically pull the backrest 5 forward or upward, so the user can easily remove and replace the backrest 5 without reading the instruction manual. Furthermore, the connecting bracket 76 is not visible when the seat 4 is attached, so there is no deterioration in aesthetics. The reinforcing pipe 59 and the tunnel section 58a also function as engagement means.

[0069] (5) Reference example In Figures 11 and 12, Reference example This indicates this. Reference example First, a convex cutout 78 is formed in the lower part of the back inner shell 21, and a movable catch 79 is integrally formed at the location of the cutout 78. The movable catch 79 has an elastically deformable arm portion 80, a lateral engaging portion 81 provided at the tip of the arm portion 80, a push-button 82 protruding forward from the tip of the arm portion 80, and return prevention pieces 83 protruding left and right from the middle of the front and rear of the arm portion 80. Return prevention piece 83 is, It constitutes part of the control measures.

[0070] On the other hand, the back outer shell 10 is provided with a pair of left and right inward-facing projections (locking parts) 84 into which the engaging part 81 of the movable catch 79 engages from below. The inward-facing projections 84 are formed on the bracket 85, and the fixed catch 85 is formed by the inward-facing projections 84 and the bracket 85. When the movable catch 79 rotates, the engaging part 81 of the movable catch 79 can move to the back side of the inward-facing projections 84.

[0071] When the push operation part 82 is pressed via the back cushion body 22, the arm portion 80 of the movable catch 79 bends and deforms, causing the engaging portion 81 to move behind the inward projection 84, thereby releasing the engagement between the inward projection 84 and the movable catch 79. The back inner shell 21 is provided with a support piece 86 on which the return prevention piece 83 rests when the arm portion 80 of the movable catch 79 bends and deforms. As a result, the arm portion 80 is held in a bent and deformed state, allowing the backrest 5 to be moved upward. The support piece 86 works in cooperation with the return prevention piece 83 to constitute a regulating means.

[0072] The front surface of the bracket 85 is an inclined surface 85a that slides downward and towards the front. When the back inner shell 21 is attached, the downward movement of the back inner shell 21 guides the engaging portion 81 to the inclined surface 85a of the bracket 85, causing it to elastically deform and rotate forward. Once the back inner shell 21 has reached its lowest point, the arm portion 80 rotates back due to its elastic restoring force, causing the engaging portion 81 to move to the lower surface of the inward projection 84. As a result, the back inner shell 21 is held in a position where it cannot move upward.

[0073] this Reference example When the push operation part 82 of the movable catch 79 is pressed via the back cushion body 22, the engaging part 81 of the movable catch 79 disengages from the inward projection 84 of the fixed catch, and the regulating means consisting of the support piece 86 and the return prevention piece 83 keeps the movable catch 79 in a free state with the engaging part 81 disengaged from the inward projection 84 of the fixed catch. Therefore, the user can use both hands to move the backrest 5 upward and remove it from the back outer shell 10.

[0074] When attaching the new backrest 5, the movable catch 79, due to the downward movement guided by the male catches 62, 64-66 and female catches 63, 67-69, contacts the inclined surface 85a of the bracket 85 in the fixed catch, rotates forward against elasticity, then, after disengaging from the bracket 85, rotates back backward, and the engaging portion 81 contacts or approaches the inward projection 84 of the fixed catch from below. Therefore, the backrest 5 is held in an irremovable position on the back outer shell 10 simply by overlapping it and sliding it downward.

[0075] The movable catch 79 engages (approaches) the inward projection 84 of the fixed catch from below when it is not elastically deformed. Therefore, the movable catch 79 will not become free unless the back cushion body 22 is locally compressed and the push operation part 82 is retracted. However, even if the lower back of the seated person comes into contact with the lower part of the back cushion body 22, the push operation part 82 will not retract, so the unforeseen situation in which the movable catch 79 becomes free while the chair is in use will not occur.

[0076] Reference example In this case, it is also possible to apply a circular or other mark by printing or embroidering to the part of the surface material covering the backrest 5 that is located in front of the push operation part 82, as a marker for the bush position.

[0077] The embodiments of the present invention have been described above, but the present invention can be materialized in various other ways. For example, If, As a jointing method, a combination of dovetail grooves and rail-shaped dovetail tenons can also be employed. [Industrial applicability]

[0078] The present invention can be implemented in a chair. Therefore, it can be used industrially. [Explanation of Symbols]

[0079] 3 base 4 seats 5. Backrest 9. Rear seat outer shell 10 Back outer shell as an example of a support member 11 Connection shaft (support shaft) 13-seat inner shell 21 Back Inner Shell 22 Back cushion body 42 Multifunctional bracket located on the back outer shell (Bracket of the claim) 48 Expandable push rivets 62, 64~66 Male catch constituting the engagement means 63, 67~69 Female catch constituting the engagement means 73 Enclosure frame section 73b back plate 76 A coupling bracket as an example of a means of preventing movement 76b Screw as an example of a fastener 79 Movable catch constituting a means of preventing movement 80 Arm section 81 Engaging part 82 Push operation section 83 Return prevention piece constituting the regulating means 84 Inward-facing projection of the fixed catch 85 Brackets that make up the fixed catch 86 Support piece constituting the regulating means

Claims

1. A backrest having a back cushion body positioned on the front of a back inner shell, and a back outer shell positioned behind the back inner shell, The chair is held in a way that the back inner shell cannot move forward relative to the back outer shell by an engaging means that engages when the back inner shell is moved downward while superimposed on the back outer shell, A connecting bracket is provided at the lower end of the back inner shell, exposed below the back cushion body, and the connecting bracket is connected to the back outer shell by a rotary or push-type fastener. chair.

2. The engaging means comprises a group of rearward-facing male catches arranged in multiple stages on the rear surface of the back inner shell, and a group of forward-facing female catches arranged in multiple stages on the front surface of the back outer shell. The chair described in claim 1.

3. The coupling bracket is hidden from the front by the seat, The chair according to claim 1 or 2.

4. The coupling bracket is fastened to a bracket provided on the back outer shell, The chair described in claim 3.

5. The fastener is a screw, The chair according to claim 1 or 2.

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