chair

Abstract

To provide a chair in which cost is reduced among a wide variety of types of products.SOLUTION: An inclined body 12 is provided inside a base 5 and a spring for rocking is also provided inside the base 5, and the body and the spring are unitized. The inclined body 12 includes a rearward projecting part 12a projecting on a rear side of the base 5, and a rear block body 14 is fixed to the rearward projecting part 12a. The rear block body 14 includes a rear part 14b positioned on a rear side of the base 5, and a side part 14a positioned on right-left outer sides of the base 5. An arm support is attached to the rear part 14b, and an armrest device 4 is attached to the side part 14a. The arm support 16 and the armrest device 4 can be attached by using the rear block body 14 while utilizing a unit in which the base 5 and the inclined body 12 are integrally incorporated. With this configuration, the cost can be reduced among a variety of types of chairs.SELECTED DRAWING: Figure 13

Description

[Technical field]

[0001] The present invention relates to a chair fitted (or capable of being fitted) with an armrest device. [Background technology]

[0002] It is common for chairs to have armrest devices attached as standard or optional accessories. There are various mounting structures for armrest devices, and examples of such mounting structures are described in the patent literature. 1,2 The document discloses that an elbow frame attachment part that protrudes outward to the left and right is integrally provided at the middle fore-and-aft section of a horizontal section of a backrest support rod that is connected to a base (support) so as to be able to tilt rearward freely and that extends rearward from a pivot point, and that the lower end of the elbow support is fixed to this elbow frame attachment part with horizontally long screws on the left and right.

[0003] The armrest device can also be fixed to a base or seat support member, but when it is fixed to the tilting frame (back frame) to which the backrest is attached, as in Patent Documents 1 and 2, the armrest device rotates together when rocking, which has the advantage of being highly responsive to the body movements of the occupant. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 3301998 [Patent Document 2] Patent No. 4943113 Summary of the Invention [Problem to be solved by the invention]

[0005] Although Patent Documents 1 and 2 have the above advantages, because the backrest support rod is connected to the base, if the design of the backrest is changed, the backrest support rod must also be modified accordingly. This causes problems in that, when stocking many models, costs increase and parts management is time-consuming.

[0006] In addition, in Patent Documents 1 and 2, the armrest device is attached to the tilting frame behind its rotation fulcrum, so that when the chair is rocked, the armrest device moves backward and downward. However, for example, if the seated person rocks the chair while operating the keyboard or mouse of a personal computer placed on the desk, the person's arms will move backward and downward significantly, which can make it difficult to operate the keyboard or mouse.

[0007] The present invention has been made to improve this current situation. [Means for solving the problem]

[0008] The present invention includes various configurations, typical examples of which are specified in each claim. The invention of claim 1 is as follows: "It comprises a base provided at the upper end of the leg support, a seat supported by the base, a tilting body rotatably connected to a portion of the base behind the leg support by a support shaft so as to tilt backward against a spring, and a block body fixed to the tilting body and to which a backrest or a back support and an armrest device supporting the backrest are attached. The base has left and right side plates and is open upward, and the tilting body is rotatably connected to the base while being disposed inside the base, The block body has a rear portion located at the rear of the base to which the backrest or the back support is attached, and a rear portion located at the left and right outer sides of the base to which the tilting body is rotated. fulcrum and an arm-like side portion extending forward beyond the seat, and a rear link is connected to a front end of the side portion for lowering and moving the seat backward when a person sits on the chair, The armrest device includes an arm support fixed to a side of the tilting body's pivot point on one side of the side of the block body, and an armrest provided on the arm support. Is " The structure is as follows.

[0009] N The block body may be referred to as a relay member.

[0010]

[0011] Claim 2 The invention is as follows: 1 In the elbow support Pillar A boss portion is provided on the side portion of the block body, an engagement hole into which the boss portion fits is formed, and the boss portion is fixed to the side portion with a screw.

[0013] Claim 3 This invention is basically the same as claim 1, with the difference being that the armrest device is not a constituent element, and an armrest holding portion to which the armrest device is attached is provided on the side portion of the block body. Effect of the Invention

[0014] In the present invention, when multiple models of chairs are available, the base and tilting body can be made into a common unit for each model. This makes it possible to reduce costs and the labor required for managing parts when offering a large number of models. In addition, the backrest or armrest support and the armrest device are attached to different locations on the block body, so they do not interfere with each other, allowing for high design freedom and preventing the load from concentrating in a narrow area, which contributes to improving support strength.

[0015] In the present invention, the armrest device tilts backward together with the backrest during rocking. , Elbow Supportis located at the pivot point of the backrest, the armrests hardly drop when rocking, and the amount of backward tilt is also small. Therefore, when rocking while operating a keyboard or mouse placed on a desk, you can simply extend your arms in response to the rocking motion and keep your wrists in the same position. This provides excellent operability for the keyboard and mouse.

[0016] As in claim 2, Boss By adopting a configuration in which the engaging hole fits into the engaging portion, the armrest device can be temporarily held in a predetermined position without having to hold it in one's hands each time it is attached, thereby reducing the labor involved in attaching the armrest device. Boss The fitting between the hole and the bolt increases the connection strength, and the support strength is also excellent. When the screw is screwed in from below, it is not visible, which makes for a good appearance.

[0017] Now, there is a chair in Patent Document 2 in which the seat moves backward and downward when a person sits down. In this chair, at least the lower end of the backrest moves forward in conjunction with the downward movement of the seat, which has the excellent advantage of providing firm support for the occupant's lower back even if the occupant sits shallowly on the chair. Also, when the seat moves backward when the person sits down, the body shifts backward even if the backrest does not move forward, so it still has an excellent function of supporting the occupant's lower back.

[0018] and, The present invention In the 2010 model, the rear link is connected to the side of the block body in front of the pivot point of the tilting body, so the rear of the seat tends to be lifted up slightly during rocking. Therefore, part of the occupant's weight acts as resistance to the rocking, but since this resistance is proportional to the occupant's weight, it is possible to maintain the same resistance to the rocking even if the occupant's weight differs. In addition, the rocking spring can be made smaller by the amount of resistance caused by the occupant's weight. [Brief description of the drawings]

[0019] [Figure 1]1A and 1B are overall views of a chair according to an embodiment, in which (A) is a front view and (B) is a side view. [Diagram 2] 1A and 1B are rear perspective views of a chair according to an embodiment, in which (A) shows the seat material and (B) omits the seat material. [Diagram 3] FIG. 1A is an exploded perspective view of the main components of the chair, and FIG. 1B is a perspective view showing the attachment state of the armrest device. [Figure 4] FIG. [Diagram 5] 1A is an exploded perspective view of the periphery of the base, and FIG. 1B is an exploded perspective view of the tilting frame and the back support. [Figure 6] FIG. 2 is a schematic vertical cross-sectional side view centered on the seat portion. [Figure 7] 13A and 13B are perspective views of a first interlocking link, and FIG. 13B is a separated perspective view of a second interlocking link and a backrest frame body, showing an interlocking means for moving the backrest forward. [Figure 8] 1A is a perspective view showing a first interlocking link and a rear block separated from each other, FIG. 1B is a perspective view showing the first interlocking link attached to the rear block, and FIG. 1C is a partial side view. [Figure 9] FIG. [Figure 10] 1A is a vertical cross-sectional side view of the front end portion of the base, and FIG. [Figure 11] FIG. 4 is a vertical sectional side view showing the relationship between a first interlocking link and a second interlocking link. [Figure 12] FIG. [Figure 13] 1A is a separated perspective view of the base and the rear block, and FIG. 1B is a separated perspective view of the rear block and the elbow support. [Figure 14] FIG. 14 is a cross-sectional view taken along line XIV-XIV of FIG. 12. [Figure 15] FIG. 13 is a cross-sectional view taken along the line XV-XV of FIG. 12. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Next, an embodiment of the present invention will be described with reference to the drawings. In this application, the terms left, right, front and back are used to specify directions, but these are based on a person normally sitting on a chair. The front view is a view seen from the direction opposite the seated person.

[0021] This embodiment is applied to a swivel chair that is widely used in offices. The chair of this embodiment is a type in which the backrest changes its posture by moving the lower end forward when a person sits down, and therefore is the same type as that of Patent Document 2.

[0022] (1) Overview: Seat lowering mechanism First, an overview of the chair and the movement of the seat will be described mainly with reference to Figures 1 to 6. As shown in Figure 1, the chair comprises a leg device 1, a seat 2, and a backrest 3 as essential elements, and also comprises an armrest device 4 as an optional item.

[0023] leg device 1 comprises a leg support 1a made of a gas cylinder, radially extending branches 1b, and side panels 5a, with casters at the tip of each branch 1b. As shown in Figures 3(B) and 4, a roughly box-shaped base 5 that opens upward is fixed to the upper end of the leg support 1a. A lid 6 is fixed to the base 5.

[0024] As shown in Fig. 13, the base 5 has left and right side plates 5a. Also, as shown in Fig. 6 and Fig. 9, the base 5 has horizontally oriented reinforcing plates 5b mounted on the left and right side plates 5a, and bushes 1c are fixed to the bottom plate and reinforcing plates 5b of the base 5 by welding, and the upper ends of the leg supports 1a are fitted into the bushes 1c.

[0025] A front block 7 made of resin or die-cast aluminum is fixed with bolts to the front end of the base 5, and a pair of left and right front links 8 are attached to the front block 7 so as to be rotatable back and forth on a horizontally long pivot shaft 9. In a neutral state where no person is seated, the front links 8 are tilted slightly backward with respect to the vertical line in a side view, and tilt backward when a person is seated.

[0026] As can be seen from Fig. 6, the rearward tilt angle is restricted by a stopper 10 provided on the rotating shaft 9 hitting the bottom surface of a recess 11 provided inside the front block 7. The front link 8 is biased by a spring (not shown) so as to return to the neutral state. The stopper 10 is fixed to the rotating shaft 9 with a screw 9a as clearly shown in Fig. 10. As shown in Figs. 6 and 10, a rearward tilting front plate 5d is disposed in front of the base 5 for reinforcement, and the front plate 5d is fixed to the side plate 5a.

[0027] For example, as can be seen from Figure 13, a tilting body 12 having left and right side plates adjacent to the left and right side plates 5a of the base 5 is arranged inside the base 5, and the tilting body 12 is connected to the base 5 by left and right long support shafts 13 so as to be freely rotatable. For example, as shown in FIG. 9, the support shaft 13 is located at a position on the base 5 behind the leg support 1a. 13, 6 and 9, the tilting body 12 has a rearward protruding portion 12a that protrudes behind the base 5, and an overlapping portion 14c of a rear block 14 is fixed to the rear portion of the rearward protruding portion 12a (details will be described later). In this embodiment, the rear block 14 corresponds to the block body recited in the claims.

[0028] As can be seen from Figures 4, 5(B), and 13(A), the rear block 14 has side portions 14a located on the left and right outer sides of the base 5, and a rear portion 14b that protrudes behind the base 5. A rear link 15 is connected to the front end of the side portion 14a by a pin, while a lower joint portion 16a of the back support 16 is fixed to the rear portion 14b. The side portion 14a is shaped like a forward-facing arm that projects in front of the pivot point (axis 13) of the tilting body 12.

[0029] For example, as shown in FIG. 5, the back support 16 has left and right vertical frames 16b. of The lower ends are connected integrally by a block-shaped lower joint portion 16a, and the upper ends of the left and right vertical frames 16b are connected integrally via an arc-shaped upper connecting portion 16c, with left and right branch portions 16d being provided at the upper ends of the vertical frames 16b.

[0030] On the other hand, the backrest 3 is configured with a mesh material 18 stretched over the front surface of a backrest frame body 17 that is open at the front and rear. To be precise, a sheet material holding frame 19 is attached to the front surface of the backrest frame body 17, and the mesh material 18 is attached to the sheet material holding frame 19. As shown in Fig. 4, the backrest frame body 17 is generally rectangular in front view and has left and right side frames, an upper frame 17a connected to the upper ends of the side frames, and a lower frame 17b connected to the lower ends of the left and right side frames, the upper frame 17a being folded back downward and rearward in side view, and the upper end of the sheet material holding frame 19 being formed into an upper shell 19a that covers the upper frame 17a.

[0031] As shown in Figures 3 and 6, the seat 2 is configured by stretching a cushion 2b on the upper surface of a seat inner shell 2a, and covering the cushion 2b from above with a skin material (not shown). The seat inner shell 2a is attached to a seat outer shell 2c made of resin. For example, as shown in Figure 1(B), 2c is connected to the front link 8 and rear link 15 by a pin 20 (see Fig. 4) that is elongated from side to side. When a person sits down, both links 8, 15 fall backwards against the spring force and rotate, causing the seat 2 to move backward and downward. As mentioned above, as shown in Fig. 3(B), the lid 6 is fixed to the upper surface of the base 5, and as can be seen from Fig. 3(A), the lid 6 is covered with a first cover 21.

[0032] For example, as shown in Fig. 1(A), levers 22a and 22b are located on the left and right lower front parts of the seat. The lever 22a on the left side as seen from the seated person is for adjusting the seat height, and the lever 22b on the right side is for controlling the rocking.

[0033] (2) Locking mechanism Next, the locking mechanism will be described. As described above, the tilting body 12 has a rearward protruding portion 12a, and as shown in Figures 6 and 9, an overlapping portion 14c provided in the left-right middle portion of the rear block 14 overlaps the rearward protruding portion 12a of the tilting body 12 from above, and the overlapping portion 14c and the rearward protruding portion 12a are fixed by a plurality of screws 23 via a pressing plate 24. Therefore, the rear block 14 and the tilting body 12 rotate together. Since the rearward protruding portion 12a, the overlapping portion 14c, and the pressing plate 24 are fastened together by the screws 23, high fixing strength can be ensured even if the rear block 14 is made of resin. Further, the overlapping portion 14c of the rear block 14 is later attached to the tilting body 12 connected to the base 2 with a screw 23.

[0034] As shown in FIG. 13(A), the pressing plate 24 has a plurality of branches 24a protruding rearward, while the overlapping portion 14c of the rear block body 14 has grooves 14c' into which the branches 24a of the pressing plate 24 fit, and the grooves 14c' into which the branches 24a fit are also fastened together with the screws 23.

[0035] 9, a torsion coil spring 25 is fitted around the support shaft 13 as an example of a spring that provides resistance to rocking. One end 25a and the other end 25b of the torsion coil spring 25 protrude in the tangential direction, with the one end 25a abutting against the front end of the rearward protruding portion 12a of the tilting body 12 and the other end 25b abutting from behind against the rear plate 5c fixed to the rear ends of the bottom plate and reinforcing plate 5b of the base 5. When the tilting body 12 tilts backward due to rocking, the torsion coil spring 25 deforms around the axis so that the distance between the one end 25a and the other end 25b narrows, thereby providing resistance to rocking.

[0036] As shown in Figure 9, A spring cover 26 is disposed behind the torsion coil spring 25 so as to cover the torsion coil spring 25. The spring cover 26 is a cover. 6 13, the spring cover 26 is formed with a slit 26a into which the tilting body 12 fits from above.

[0037] 6 and 9, the lower joint part 16a of the back support 16 is fixed to the rear part 14b of the rear block 14 with a screw 28 and a nut 28a. As shown in Fig. 5(B), about the front half of the lower joint part 16a overlaps with the rear part 14b of the rear block 14 from below. In addition, the lower joint part 16a is provided with a pair of left and right forward engaging parts 29, which fit into engaging grooves 30 formed in the rear part 14b of the rear block 14 from below.

[0038] When a seated person leans against the backrest 3, the back support 16, rear block 14, and tilting body 12 tilt backward together around the support shaft 13 while elastically deforming the torsion coil spring 25. In addition, since the rear link 15 is connected to the rear block 14, the rear link 15 also moves together with the rear block 14, but since the tip of the side part 14a to which the rear link 15 is attached is located slightly forward of the support shaft 13, the rear link 15 rises slightly during rocking.

[0039] Therefore, not only the torsion coil spring 25 but also part of the weight of the seated person acts as resistance against rocking, but the magnitude of this resistance is proportional to the weight of the seated person, so it is possible to obtain an appropriate rocking resistance without enlarging the size of the torsion coil spring 25. In other words, the resistance against rocking is proportional to the weight of the seated person. automatically Therefore, the torsion coil spring 25 can be made smaller.

[0040] For example, as shown in Fig. 13, the left and right side plates of the tilting body 12 extend forward along the side plate 5a of the base 5, and a horizontally long rod 12b is mounted between the front ends of the left and right side plates. This rod 12b is for controlling the locking of the backrest 3. In other words, by selectively engaging multiple engagement portions provided on a locking member (not shown) with the rod 12b, the backrest 3 can be tilted backward in multiple stages. One of When the locking member is not engaged with the rod 12b, the backrest 3 is free to tilt.

[0041] As shown in FIGS. 4 and 5, the rear block 14 and Bottom of back support 16 The upper surface of the joint portion 16a is covered with a pair of second covers 31 on the left and right sides. The back support 16 is made of resin or aluminum die-cast. Similarly, the front block 7 and rear block 14, resin It is made of aluminum or die-cast aluminum.

[0042] The side portion 14a of the rear block 14 is provided with an armrest holder at a position generally at the same front-rear position as the support shaft 13. This armrest holder has an elbow rest support outward projection 32, generally triangular in side view, protruding outward to the left and right, and an elbow rest attachment hole 33 opens outward to the left and right in the elbow rest support outward projection 32. This will be described later.

[0043] (3) Backrest advancement mechanism As described above, in this embodiment, when a person sits down, the backrest 3 can change its position so that its lower end moves forward. This change in position of the backrest 3 is achieved by the first interlocking link 35 and the second interlocking link 36, the entirety of which is shown in Fig. 7. The first interlocking link 35 has a base 35a that is long from side to side, arm parts 35b that extend forward from both left and right ends of the base 35a, and a pushing part 35c that extends backward from the middle part of the base 35a. As shown in Fig. 4, the base 35a overlaps the rear block 14 and the lower joint part 16a behind the base 5.

[0044] The left and right arm portions 35b are disposed on the left and right outer surfaces of the base 6, and as shown in FIGS. 7(A) and (B), a pivot hole 37 is formed in the middle of the arm portion 35b in the front to rear direction. As shown in FIGS. 7(A) and 8(B), the pivot hole 37 is fixed to the rear block 14 by a shoulder bolt 35d which also serves as a pin. Side section (Note that in FIG. 8(B) only one shoulder bolt 35d is shown.) Therefore, the first interlocking link 35 can rotate up and down like a seesaw around the pivot hole 37.

[0045] The shoulder bolts 35d are inserted into the pivot holes 37 from the left and right inner sides of the arm portion 35b. Side section As shown in FIG. 8(B) by reference numeral 14f, the rear block 14a has a nut holding hole that opens upward and communicates with the pivot hole 37, and the shoulder bolt 35d is screwed into the nut holding hole 14f. As shown in FIG. 8(C), Side section A through hole 14e is provided in 14a to allow the tip of shoulder bolt 35d to escape.

[0046] As can be seen from FIGS. 8(A) and 8(B), the rear block 14 is provided with a first interlocking link 35. base 35a fits in Polymerization section 14c. In addition, the rear block 14 Side section At the tip of 14a, a space 14d is formed to allow the tip of arm portion 35b to rotate.

[0047] The tip of the arm portion 35b engages with an engagement claw 38 that protrudes downward from the bearing portion 15a of the rear link 15. When the rear link 15 is in a neutral state, the engagement claw 38 extends rearward in a position that is slightly tilted backward from the horizontal, and the tip of the arm portion 35b is formed with an upward-opening engagement groove 39 into which the engagement claw 38 fits from above. Therefore, when a person sits down and the rear link 15 tilts backward, the first interlocking link 35 rotates so that its front end descends and its rear end ascends.

[0048] As shown in Fig. 11, the lower end of the second interlocking link 36 is connected to the rear end (upper end) of the pushing portion 35c of the first interlocking link 35 by fitting from above. 35e On the other hand, a female fitting portion 36a is provided at the lower end of the second interlocking link 36, and these are fitted together and fixed with a screw 41 and a nut 42. Therefore, the relative position between the pushing portion 35c and the second interlocking link 36 does not change.

[0049] As shown in FIG. 7(C), the upper end of the second interlocking link 36 is formed with a clip portion 40 that opens forward in a side view, while the lower frame 17b of the backrest frame body 17 constituting the backrest 3 is provided with left and right ribs 43 that sandwich the clip portion 40 from the left and right, and the left and right ribs 43 are integrally provided with pin portions 44 into which the clip portion 40 fits by deformation against elasticity.

[0050] 11, a boss portion 36b that protrudes toward the front in a side view is formed in the left-right intermediate portion of the second interlocking link 36. A screw 45 is disposed in front of the boss portion 36b, and this screw 45 is for fixing the lower frame 17b of the backrest frame 17 and the lower member of the seat material holding frame 19 together.

[0051] For example, as can be easily understood from Fig. 5(A), the upper end of the second interlocking link 36 is located far above the pivot point of the first interlocking link 35. Therefore, when the first interlocking link 35 rotates due to sitting down, the second interlocking link 36 moves forward as a whole. As a result, the posture of the backrest 3 changes so that its lower end moves forward.

[0052] The amount of forward movement of the backrest should change depending on the posture of the person sitting down. In other words, it is necessary to devise a way to stop the backrest when it comes into contact with the person's back, whether the person is sitting shallowly or deeply, without being pushed forward by the forward movement of the backrest. Therefore, the part of the arm part 35b of the first interlocking link 35 behind the pivot hole 37 is made into a deformation-permitting part 35b', and by bending and deforming this deformation-permitting part 35b' in the vertical direction, the lower part of the backrest 3 comes into contact with the person's back (waist) and does not move forward any further, while allowing the rear link 15 to rotate.

[0053] Patent document 2 also has this kind of function, and in this document a spring means is used to absorb differences in the depth at which a person sits. However, by utilizing the elastic deformation of the first interlocking link 35 as in this embodiment, the number of parts can be reduced, significantly reducing costs, and this has the advantage of contributing to reducing the effort required for assembly and improving assembly accuracy.

[0054] (4) Armrest device mounting structure Next, the mounting structure of the armrest device 4 will be described. For example, as can be easily understood from FIG. 3B, the armrest device 4 of this embodiment is a type that can adjust the height, and has an arm support 47 and an armrest 48. do.

[0055] The elbow support 47 has a hollow standing section 49 and a horizontal section 50 extending inwardly to the left and right from the bottom end of the standing section 49. A lifting body 51 is fitted into the standing section 49 so as to be movable up and down, and an elbow pad 48 is attached to the top end of the lifting body 51 directly or via an intermediate member. A lever 52 for releasing the lock is attached to the top end of the lifting body 51. The armrest device may be a fixed elbow whose height cannot be adjusted.

[0056] As described above, the side portion 14a of the rear block body 14 has an elbow rest support outward protrusion 32 protruding outward, and elbow rest attachment holes 33 open outward to the left and right at the elbow rest support outward protrusion 32. On the other hand, the horizontal portion 50 of the elbow support column 47 has a hole 33 that fits into the elbow rest attachment hole 33. Boss 53 is provided, and as shown in FIG. Boss 53 is fixed to the side portion 14a by two screws 54 at the front and rear.

[0057] Boss A pocket 56, into which a nut 55 fits non-rotatably, is formed in the upper surface of 53 so as to open upward. Also, a countersunk hole 57 into which the head of the screw 54 is hidden is formed in the lower surface of the side portion 14a of the rear block body 14.

[0058] As can be seen from Figure 13(B), Boss53 and the armrest mounting hole 33 are trapezoidal in shape with a narrower top when viewed from the side. Boss When the screw 53 is fitted into the armrest mounting hole 33, the armrest device 4 is held so as not to be able to rotate forward or backward. Therefore, the screw 54 can be screwed in without having to hold the armrest device 4 with one's hand each time.

[0059] Also, Boss The end face 50a of the horizontal portion 50 extends all around the base of the elbow support 47, and overlaps with the tip face of the elbow support outward protrusion 32. Therefore, part of the downward load acting on the elbow support 47 is also supported by the end face 50a of the horizontal portion 50 abutting against the elbow support outward protrusion 32. Therefore, even though it is attached with two screws 54, high fastening strength can be maintained.

[0060] As can be seen from Figure 12, Elbow pads The outward support protrusion 32 is disposed almost directly to the side of the support shaft 13. Therefore, during rocking, the arm support 47 only tilts backward around its lower end, and does not move downward as a whole. For this reason, when a seated person operates a keyboard or mouse placed on a desk, the arm of the seated person does not move backward. stretch Therefore, it is suitable for performing desk work while leaning against the backrest 3.

[0061] When the screw 54 is screwed in from below as in the embodiment, the screw 54 is not entirely visible, which is aesthetically pleasing. Boss Since the screws 53 and 54 are in a crossed position, the fastening strength is also excellent. Boss With respect to the external force in the pull direction of 53, 54 Since a shear force acts on the joint, it provides high fastening strength.

[0062] As shown in Fig. 14, the support shaft 13 is rotatably held on the side plate 5a of the base 5 via bearings 58 provided on both ends. The bearings 58 do not penetrate the side plate 5a, but the side plate 5a and the bottom and reinforcing plate 5b of the base 5 are separate members, and after the support shaft 13 is mounted, the side plate 5a is fixed to the bottom and reinforcing plate 5b. The support shaft 13 is fitted into the tilting body 12 via a bushing 59.

[0063] The base 5, tilting body 12, and spring 25 are integrated into a unit, and this unit can be used for various models. When developing a new model, the rear block body 14 can be designed as a dedicated part, or the rear block body 14 can be used in common and only the back part can be redesigned, thereby saving the effort required for design and manufacturing.

[0064] In this embodiment, the backrest is made of mesh, but it may be made of an inner shell with a cushion. The support structure of the backrest by the block body may be selected appropriately according to the structure of the backrest. The relationship between the base and the tilting body may also be embodied in various ways. For example, the side plate of the tilting body may be disposed outside the base. stomach. [Industrial Applicability]

[0065] The present invention can be embodied in a chair, and therefore has industrial applicability. [Explanation of symbols]

[0066] 3. Backrest 4 Armrest device 5. Bass 12 Tilting body 12a Rearward-facing protrusion 13 Axle that serves as the pivot point for the tilting body 14 Rear block (block body in the claim) 14a Side section 14b Rear section 14c Polymerization part 15 Rear link 16 Back strut 16a Lower joint of back support 23 Screw for fixing the rear block body to the tilting body 28 Screws for fixing the back support to the rear block body 32 Elbow support outward protrusion constituting the armrest holding portion 33 Armrest mounting hole constituting armrest support 47 Elbow Support 48 Elbow pad 49 Standing part 50 horizontal part 51 Lifting body 53 Boss section 54 Screws for fixing the elbow support to the rear block body 55 Nut

Claims

1. The chair comprises a base provided on the upper end of the leg support, a seat supported by the base, a tilting body rotatably connected to a portion of the base behind the leg support by a support shaft so as to tilt backward against a spring, and a block body fixed to the tilting body and to which a backrest or a back support and an armrest device supporting the backrest are attached, The base has left and right side plates and is open upward, and the tilting body is rotatably connected to the base while being disposed inside the base, the block body has a rear portion located behind the base and to which the backrest or back support is attached, and arm-like side portions located on the left and right outer sides of the base and extending forward beyond the pivot point of the tilting body, and a rear link is connected to the front end of the side portion for lowering and moving the seat backward when a person sits down, The armrest device has an arm support fixed to a side portion of the side part of the block body on the lateral side of the pivot point of the tilting body, and an armrest provided on the arm support. chair.

2. The elbow support is provided with a boss portion, The block body has a side portion provided with an engagement hole into which the boss portion fits. The boss portion is fixed to the side portion with a screw.

2. A chair as claimed in claim 1.

3. The chair comprises a base provided on the upper end of the leg support, a seat supported by the base, a tilting body rotatably connected to a portion of the base behind the leg support by a support shaft so as to tilt backward against a spring, and a block body fixed to the tilting body and to which a backrest or a back support supporting the backrest is attached, The base has left and right side plates and is open upward, and the tilting body is rotatably connected to the base while being disposed inside the base, the block body has a rear portion located behind the base and to which the backrest or back support is attached, and arm-like side portions located on the left and right outer sides of the base and extending forward beyond the pivot point of the tilting body, and a rear link is connected to the front end of the side portion for lowering and moving the seat backward when a person sits down, An armrest holder is provided at a portion of the side portion of the block body immediately to the side of the pivot point of the tilting body to attach the armrest of an armrest device having an armrest on the armrest. chair.

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