Rotor connection structure and chair

Abstract

The invention provides a rotating body connecting structure which can simply mount a rotating body to a rotating shaft. The rotating body connecting structure is a structure (10) for connecting a cushion support (d1), which is a rotating body, to a synchronizing shaft (J2), which is a rotating shaft, and connects the cushion support (d1) so that the cushion support (d1) can rotate around the outer peripheral surface of the synchronizing shaft (J2). A synchronizing shaft mounting part (d11) serving as a communication part for communicating the lower surface and the upper surface of a seat cushion support (d1) and an arc-shaped abutting part (d11b) serving as an abutting part for abutting a synchronizing shaft (J2) inserted from the lower surface side of the synchronizing shaft mounting part (d11) are arranged on the seat cushion support (d1), and an opening hole (d12) communicated with the synchronizing shaft mounting part (d11) is formed in the upper surface of the seat cushion support (d1). A stopper (d13) that is movably fitted to the outer peripheral surface of the synchronizing shaft (d11) and prevents the synchronizing shaft (d11) from falling off from the cushion support (d1) is removably attached to the opening hole (d12).

Description

Technical Field

[0001] The present invention relates to a rotating body connection structure that connects rotating bodies to a rotating body that can rotate along the outer peripheral surface of a rotating axis, and a chair. Background Technology

[0002] For example, Patent Document 1 (Japanese Patent No. 3506901) discloses a structure for performing a so-called synchronized swinging motion, in which the seat cushion of a chair rotates in sync with the backrest. In the conventional chairs including Patent Document 1, during the fitting operation between the synchronizer shaft and the fitting portion formed on the seat cushion support, in order to make the hook-shaped fitting portion formed on the lower surface of the seat cushion support hold the synchronizer shaft, the synchronizer shaft is pressed against the hook-shaped fitting portion, causing the hook-shaped fitting portion to elastically deform, thereby causing the hook-shaped fitting portion to hold the synchronizer shaft.

[0003] Patent Document 1: Japanese Patent No. 3506901 (Claim 1, Figure 1 and Figure 4 wait)

[0004] However, the installation method of mounting this synchronous shaft (rotating shaft) to the seat support (rotating body) requires deformation of the hook-shaped fitting part, which poses a risk of damage to the hook-shaped part due to the force during installation and a decrease in the strength of the hook-shaped part due to long-term aging. In addition, in recent years, from the perspective of sorting and disposal upon disposal, there has been a desire to provide a connected structure that users can easily assemble and disassemble. Summary of the Invention

[0005] In view of the above situation, the present invention aims to provide a rotating body connecting structure and a chair that allows for easy mounting of the rotating body to the rotating axis.

[0006] In order to solve the above problems, the inventors conducted in-depth research and came up with the following structure.

[0007] That is, the present invention is a rotating body connection structure that connects rotating bodies to form a rotating body connection structure that can rotate along the outer peripheral surface of a rotating shaft. The rotating body is provided with a connecting part that connects the lower surface of the rotating body to the upper surface, and an abutting part for the rotating shaft to be inserted from the lower surface side of the connecting part to abut. An opening hole that communicates with the connecting part is formed on the upper surface of the rotating body. A stop body that is movably fitted with the outer peripheral surface of the rotating shaft and used to prevent the rotating shaft from falling off the rotating body is detachably installed in the opening hole.

[0008] Therefore, it is easy to install the rotating body onto the rotating shaft.

[0009] Furthermore, it is preferable that the opening is located in a different plane from the abutment portion.

[0010] Therefore, fewer components are needed to disperse the contact positions relative to the rotation axis along the long side.

[0011] Furthermore, it is preferable that the connecting portion is provided with an inclined surface forming body that is inclined in a front-back direction from the lower surface of the rotating body toward the upper surface of the rotating body, and the opening hole is formed as a reverse inclined hole that is inclined in the opposite direction to the inclined surface formed by the inclined surface forming body.

[0012] Therefore, even when the rotating body with the rotating shaft installed is lifted upwards, the rotating shaft can be prevented from falling off the rotating body.

[0013] Furthermore, it is preferable that an engaging recess is formed in the opening, which engages with a protrusion formed on the rear side of the upper part of the stop to prevent positional displacement, or that an engaging claw is formed in the stop to engage with a portion of the inner circumferential surface of the reverse inclined hole.

[0014] Therefore, it is possible to prevent the stop body installed in the opening hole of the connecting part from shifting position, thereby increasing the difficulty of the rotating shaft falling off the rotating body.

[0015] Furthermore, the present invention is a chair capable of synchronously swinging, causing the seat cushion and backrest to tilt and move in tandem, by means of a rotating shaft. The rotating shaft is disposed in front of the backrest. The seat cushion is provided with a connecting portion that connects the upper surface and the lower surface of the seat cushion, and an abutting portion for the rotating shaft to abut against when inserted from the lower surface side of the connecting portion. A stop body that is movably fitted with the outer peripheral surface of the rotating shaft and used to prevent the rotating shaft from falling off the seat cushion is detachably installed in an opening hole. The opening hole communicates with the connecting portion and is open on the upper surface of the seat cushion.

[0016] Furthermore, the opening is positioned in a different plane from the abutment portion.

[0017] Therefore, it is easy to install the rotating body onto the rotating shaft.

[0018] Furthermore, it is preferable that the connecting portion is provided with an inclined surface forming body that is inclined in a front-to-back direction from the lower surface of the cushion toward the upper surface of the cushion, and the opening hole is formed as a reverse inclined hole that is inclined in the opposite direction to the inclined surface formed by the inclined surface forming body.

[0019] Therefore, even when the rotating body with the rotating shaft installed is lifted upwards, the rotating shaft can be prevented from falling off the rotating body.

[0020] Furthermore, it is preferable that an engaging recess is formed in the opening, which engages with a protrusion formed on the rear side of the upper part of the stop to prevent positional displacement, or that an engaging claw is formed in the stop to engage with a portion of the inner circumferential surface of the reverse inclined hole.

[0021] Therefore, it is possible to prevent the stop body installed in the opening hole of the connecting part from shifting position, thereby increasing the difficulty of the rotating shaft falling off the rotating body.

[0022] As described above, the rotating body connecting structure and the chair structure according to the present invention allow for easy installation of the rotating body and seat cushion onto the rotation axis. Furthermore, the installation of the rotating body and seat cushion onto the rotation axis can be performed without applying unreasonable forces, and damage to the connecting portion during installation of the rotating body and seat cushion onto the rotation axis can be prevented. Attached Figure Description

[0023] Figure 1 This is a perspective view of the front side of the chair in this embodiment. Figure 2 This is a perspective view of the rear side of the chair in this embodiment. Figure 3 This is a front perspective view showing the seat cushion disassembled after the armrests have been removed and it has been detached from the support base. Figure 4 It is a magnified 3D view of the perimeter of the support base. Figure 5 This is a 3D view of the lower side of the seat cushion support. Figure 6 This is a top view of the seat cushion support. Figure 7 yes Figure 6 A rough cross-sectional view of line VII-VII within the interior. Figure 8 (A) is a three-dimensional view of the front side of the pressing plate. Figure 8 (B) is a three-dimensional view of the rear side of the pressing plate. Figure 9 yes Figure 6 A rough cross-sectional view at the IX-IX line within the inner section. Figure 9 (A) is a diagram before the stop is installed. Figure 9 (B) is a diagram after the stop body is installed. Figure 10 (A) is a three-dimensional view of the front side of the stop. Figure 10 (B) is a three-dimensional view of the rear side of the stop. Figure 11 This is a three-dimensional view of the front side of the back support. Figure 12 It is a front-view perspective view showing the backrest in its disassembled state. Figure 13It is a rear three-dimensional view showing the backrest in its disassembled state. Figure 14 (A) is the front view of the first fabric card assembly. Figure 14 (B) is the front view of the second fabric card assembly. Figure 15 This is an explanatory diagram showing the engagement state of the first fabric fastener towards the back frame. Figure 16 It is a 3D view of the back frame and lumbar support. Figure 17 This is the front view of the lumbar support component. Figure 18 This is one of the exploded three-dimensional diagrams of the pelvic operating parts. Figure 19 This is the second exploded three-dimensional view of the pelvic operating part. Figure 20 This is a 3D view of the front of the headrest. Figure 21 This is a front perspective view showing the headrest with the clamp removed. Figure 22 (A) is a rear perspective view of the block of the height adjustment mechanism. Figure 22 (B) is a front perspective view of the block of the height adjustment mechanism. Figure 23 This is a side view showing the state of the block and cam surface. Figure 24 It is a cross-sectional view showing the state of the block and the cam surface. Figure 25 It is a cross-sectional view showing the state in which the block is prevented from falling off by the anti-detachment stop. Figure 26 It is a cross-sectional view showing the state of a block that is not in the installation state, which is restricted by the anti-misinstallation stop. Figure 27 This is a 3D view of the back of the headrest. Figure 28 It means from Figure 27 A rear 3D view showing the state after the decorative frame has been removed. Figure 29 This is an explanatory diagram showing the method of installing fabric with the third and fourth fabric fasteners onto the frame. Figure 30 This is a rear view of the fabric with the third and fourth fabric clips installed. Figure 31 (A) is the front view of the fourth fabric card assembly. Figure 31 (B) is a front view showing the fourth fabric clasp extending along its length. Figure 31 (C) is a front view showing the state of the fourth fabric card assembly compressed along its length. Figure 31 (D) is a front view showing the state of the fourth fabric assembly bent relative to the length direction. Figure 32 This is a front-view perspective view showing the disassembled state of the handrail. Figure 33 It is a rear three-dimensional view showing the disassembled state of the handrail. Figure 34 This is a frontal perspective view showing the elbow support disassembled. Figure 35 (A) is a partial side view showing the state when the elbow support is moved rearward. Figure 35 (B) is a top view representing the main part of the same state. Figure 35 (C) is a top view representing the first path in the same state. Figure 35 (D) is a top view of the second path section representing the same state. Figure 36 (A) is a partial side view showing the state when the elbow support is moved forward. Figure 36 (B) is a top view representing the main part of the same state. Figure 36 (C) is a top view representing the first path in the same state. Figure 36 (D) is a top view of the second path section representing the same state. Figure 37 (A) is a partial side view showing the state when the elbow rest is moved forward and inward. Figure 37 (B) is a top view representing the main part of the same state. Figure 37 (C) is a top view representing the first path in the same state. Figure 37 (D) is a top view of the second path section representing the same state. Detailed Implementation

[0024] An embodiment of the present invention will now be described with reference to the accompanying drawings. In addition, in this specification, “up” and “down”, “front” and “back”, and “left” and “right” are defined based on the person sitting on the seat cushion D of chair A (in other words, “up” and “down”, “front” and “back”, and “left” and “right” as viewed from the person’s perspective).

[0025] This embodiment illustrates the application of the present invention in a connection structure where the seat support d1, which is a rotating body, is connected to the synchronous shaft J2, which is a rotating axis.

[0026] like Figures 1-3As shown, the chair A in this embodiment includes chair legs B, a support base C rotatably supported on the chair legs B, a seat cushion D disposed above the support base C, a backrest structure F supported on the support base C in a way that allows it to tilt backward relative to the support base C, a headrest X mounted on the backrest structure F, and armrests Y mounted on the seat cushion D. The backrest structure F includes a back support body G supported on the support base C and a backrest H supported on the back support body G.

[0027] The following is a detailed description of the various structures of chair A.

[0028] (Chair leg B) Chair leg B comprises multiple leg blades b2 arranged radially with casters b1 at the top, and leg supports b3 erected at the base of these leg blades b2. The leg supports b3 are extendable and retractable in the vertical direction. The leg supports b3 have a gas spring (not shown) that supports the support base C, allowing for vertical repositioning. Furthermore, the specific shape of chair leg B is not particularly limited, and other known structures may be appropriately employed.

[0029] (Support base C) Figure 4 yes Figure 3 A perspective view of the peripheral portion of the support base C in this embodiment. The support base C in this embodiment is formed as a bottomed box shape. A mounting hole c1 is formed on the rear bottom surface of the support base C (see reference). Figure 2 The support base C is installed on the upper part of the chair leg support b3 by inserting the chair leg support b3 into the mounting hole c1. A rotating shaft J1 for swinging motion, a synchronous shaft J2 serving as the rotating shaft, and a locking shaft J3 for locking the first end of the reaction spring c2 during swinging are mounted on the left and right sides of the support base C. The second end of the reaction spring c2 engages with the reaction spring support c3 disposed on the support base C. The rotating shaft J1, synchronous shaft J2, and locking shaft J3 all pass through a chain plate c4, which is disposed between the left and right walls. The arm g1 of the back support body G is connected to the rotating shaft J1. The seat support d1 of the seat cushion D is fitted with the synchronous shaft J2 in a manner that allows rotation about the axis of the synchronous shaft J2, which is positioned further forward than the rotating shaft J1 to which the arm g1 of the back support body G is connected. One end of the reaction spring c2 engages with the locking shaft J3. The chain plate c4 achieves the swinging motion by rotating around the rotating shaft J1. Furthermore, during the swinging motion of the backrest H, the seat cushion D moves synchronously with the swinging motion using the chain plate c4 and the synchronous shaft J2. Thus, the rotating shaft J1, the synchronous shaft J2, the locking shaft J3, and the chain plate c4 form a synchronous swinging mechanism, achieving synchronous swinging motion.

[0030] Furthermore, arc-shaped elongated holes c5 are formed on the left and right walls of the front end portion of the support base C. A shaft J4 is arranged between these elongated holes c5 in a left-right direction. When the backrest H swings, the elongated holes c5 and the shaft J4 guide the movement of the seat cushion D using the chain plate c4 and the synchronous shaft J2, causing it to move along a predetermined trajectory. Furthermore, the shaft J4 also serves as part of the forward tilting mechanism of the seat cushion D, described later. A swing force adjustment lever c6 is arranged on the front right side of the support base C, which adjusts the working force required for the swinging motion. A swing operation lever c7 is arranged on the rear left side of the support base C, which switches the locking on and off at the initial position (standing position) of the swinging motion. Regarding... Figure 3 and Figure 4 The other components of the support base C shown are well known, and therefore their description is omitted here.

[0031] (Seat Cushion D) like Figure 3 As shown, the seat cushion D includes a shell-shaped seat cushion support d1 that serves as a rotating body, and a seat cushion body d2 and a cushion d3 mounted on the seat cushion support d1 in a manner that allows for changing their front and rear positions. Furthermore, as... Figures 5-7 As shown, a recess d4 with an opening on the lower surface is formed on the front side of the lower surface of the seat support d1. Two protrusions d5 with arc-shaped lower surfaces are erected in the recess d4. A shaft receiving hole d6 is provided through the outer side of the protrusions d5 in the left-right direction, and the shaft receiving hole d6 is aligned at the same height as the arc surface of the protrusions d5. The shaft J4 passes through the left and right shaft receiving holes d6. In this state, the upper surface of the shaft J4 abuts against the arc surface of the protrusions d5. An opening d7 is arranged on the upper surface of the seat support d1 in a plane position outside the shaft receiving hole d6 in the left-right direction. As shown in the side cross-sectional view of the seat D, in the opening d7, the spring retainer d8 and the spring d9 are received from the shaft J4 side (lower side) on the upper surface of the shaft J4 in the order described above. In addition, a pressing plate d10 is installed at the opening d7 to accommodate the spring d9 in a stressed state.

[0032] like Figure 8As shown, the pressing plate d10 is rectangular when viewed from above. An upwardly projecting upper protrusion d10a is formed on one end edge along its long side. A front protrusion d10b, projecting along the long side of the pressing plate d10, is formed on the end face opposite to the side where the upper protrusion d10a is formed. A rear entry portion d7a is formed in the opening d7 of the seat support member d1, through which the upper protrusion d10a passes. A fitting hole d7b is formed behind and adjacent to the rear entry portion d7a, for the upper protrusion d10a to engage. Furthermore, a front entry portion d7c is formed in front of the opening d7, allowing the front protrusion d10b to enter. The planar positions of the fitting hole d7b and the front entry portion d7c are aligned with the planar positions of the upper protrusion d10a and the front protrusion d10b of the pressing plate d10. In addition, the depth dimension of the rear entry section d7a is formed to be greater than the length dimension of the long side of the pressing plate d10.

[0033] After the spring retainer d8 and spring d9 are received in the aforementioned opening d7, the pressing plate d10 is installed into the opening d7 while pressing (compressing) the spring d9 downwards. Specifically, the pressing plate d10 slides backwards in the downward-opening state, causing the upper protrusion d10a to temporarily pass through the fitting hole d7b, until the pressing plate d10 is fully received into the opening d7, moving the pressing plate d10 to the inside position of the rear entry portion d7a. After the pressing plate d10 is fully received into the opening d7, if the pressing force on the spring d9 is released, the pressing plate d10 slides forward, and the upper protrusion d10a engages with the fitting hole d7b, and the front protrusion d10b enters the front entry portion d7c. The pressing plate d10 is installed in a state that prevents it from falling off relative to the opening d7. Since the spring d9 is in a state where it is subjected to a predetermined force by the pressing plate d10, the upper protrusion d10a remains engaged with the fitting hole d7b, and the pressing plate d10 will not fall off from the opening d7.

[0034] Thus, the seat support d1 can utilize the shaft J4 held at the support base C, the spring retainer d8 and spring d9 carried on the shaft J4, and the pressing plate d10 to allow the spring d9 to reciprocate within a compressible range between the height position of the upper surface of the shaft J4 and the height position of the lower surface of the pressing plate d10. That is, if the occupant overcomes the force of the spring d9 and applies a downward force (external force) to the front part of the seat cushion D, the seat cushion D can be tilted forward. If the seat cushion D is tilted forward, the force of the spring d9 increases; if the external force applied to the seat cushion D is released, the seat cushion D returns to its initial position due to part of the accumulated force. At this time, the shaft J4 reciprocates obliquely up and down along the elongated hole c5 formed in the support base C.

[0035] In addition, such as Figure 5 As shown, a synchronous shaft mounting portion d11 is provided at the center of the lower surface of the seat support member d1. The synchronous shaft mounting portion d11 is a connecting portion that connects the upper and lower surfaces of the seat support member d1. In this embodiment, the synchronous shaft mounting portion d11 has multiple inclined protrusions d11a, which are inclined surface forming bodies, erected towards the lower side of the seat support member d1, and multiple arc-shaped abutment portions d11b, which are abutment portions with arc-shaped abutment surfaces. Both the inclined protrusions d11a and the arc-shaped abutment portions d11b are formed as ribs and are arranged along the length direction of the synchronous shaft mounting portion d11. When mounting the seat support member d1 to the synchronous shaft J2, simply insert the synchronous shaft J2 along the inclined protrusions d11a into the synchronous shaft mounting portion d11 and abut the outer peripheral surface of the synchronous shaft J2 against the arc-shaped abutment portions d11b. By abutting the synchronous shaft J2 against the arc-shaped abutment part d11b, the seat support d1 can be installed relative to the synchronous shaft J2 in a proper state.

[0036] Figure 9 This is a cross-sectional view of the main part showing the seat support d1 installed on the synchronous shaft J2. From Figure 9 As can be clearly seen from (A), an opening hole d12 is formed on the upper surface of the seat support d1, communicating with and opening the synchronous shaft mounting portion d11. In this embodiment, the opening hole d12 is positioned in the same longitudinal direction as the arcuate abutment portion d11b in the longitudinal (left-right) direction of the synchronous shaft mounting portion d11. Alternatively, the opening hole d12 may be positioned in a different longitudinal direction than the arcuate abutment portion d11b in the longitudinal (left-right) direction of the synchronous shaft mounting portion d11. In a side view, the opening hole d12 is formed in a shape that intersects with the inclined surface d11x of the inclined protrusion d11a. More specifically, an inclined surface d11x is formed on the inclined protrusion d11a, which extends from the lower surface opening that opens downwards and forwards toward the upper rearwards. In this regard, the opening d12 is formed as a reverse inclined hole, which extends along the direction from the lower surface opening that opens downward and backward toward the upper front (inclining in the opposite direction to the inclined surface d11x). As a result, the shape when viewed from the side is V-shaped due to the inclined surface d11x formed by the inclined protrusion d11a and the inner peripheral surface d12x of the opening d12.

[0037] A first engaging recess d12a is formed on the inner circumferential surface d12x of the opening hole d12, and a second engaging recess d12b is formed around the opening of the opening hole d12 on the upper surface of the seat support member d1 (see reference). Figure 6 In addition, such as Figure 9As shown in (B), a stop body d13 is installed in the opening hole d12 to prevent the synchronous shaft J2 from detaching from the synchronous shaft mounting part d11. Figure 9 As shown in (B), by installing a stop body d13 in the opening hole d12, a seat support member and a synchronous shaft connection structure 10 are formed as a rotating body connection structure, and the seat support member d1 is connected so that it can rotate along the outer peripheral surface of the synchronous shaft J2.

[0038] like Figure 10 As shown, the stop body d13 is formed into a generally L-shaped body in side view, having an upper part d13a and an inclined part d13b. The upper surface of the upper part d13a has a grid pattern identical to the grid pattern on the upper surface of the seat support member d1. A rearwardly projecting protrusion d13c, serving as a positional offset prevention protrusion, is formed on the rear side of the upper part d13a. The inclined part d13b is formed to be inclined in the same way as the inner circumferential surface d12x of the opening hole d12, and is configured to allow access to the opening hole d12. A locking claw d13d protrudes from the front of the inclined part d13b. The locking claw d13d is formed as a cantilever beam that can protrude and retract relative to the front of the inclined part d13b through elastic deformation. A lower protrusion d13e is formed at the lower end of the inclined part d13b. A synchronous shaft fitting part d13f is formed by the lower surface side of the upper part d13a and the rear side of the inclined part d13b, which has an arc-shaped inner bottom surface.

[0039] The stop d13 thus formed is installed by inserting the inclined portion d13b along the inner circumferential surface d12x of the opening hole d12 from the upper surface of the seat support d1. At this time, the engaging claw d13d formed in front of the inclined portion d13b moves along the inner circumferential surface d12x of the opening hole d12 while elastically deforming. If the engaging claw d13d reaches the position of the first engaging recess d12a formed in the inner circumferential surface d12x of the opening hole d12, the elastic deformation of the engaging claw d13d is restored, and it engages with the first engaging recess d12a, thus preventing the stop d13 from falling off. In this state, the rear protrusion d13c also engages (fits) with the second engaging recess d12b formed in the opening of the opening hole d12. That is, it can restrict movement in both directions of the synchronous shaft J2 and the synchronous shaft engaging portion d13f from being in a state of active engagement or engagement. In addition, the lower protrusion d13e is used as a reinforcement to strengthen the lower end of the synchronous shaft fitting part d13f.

[0040] Thus, the seat support d1, equipped with the synchronous shaft J2 and the stop body d13, becomes effective even when the seat support d1 is pulled upwards. Figure 9The force in the direction of arrow A within (B) restricts the movement of the seat support d1 in the direction of arrow A by the stop d13. This prevents the seat support d1 from detaching from the synchronizing shaft J2. Furthermore, the seat support d1 can be easily removed from the synchronizing shaft J2 simply by pulling the stop d13 out of the opening d12 of the seat support d1. Thus, the seat support d1 in this embodiment is advantageous in that it can be installed and disassembled onto the synchronizing shaft J2 without the use of tools. Therefore, the seat D installed on the synchronizing shaft J2 is configured to move synchronously with the tilting motion (swinging motion) of the backrest H via the rotating shaft J1, the chain plate c4, and the synchronizing shaft J2.

[0041] (Backrest structure F) The backrest structure F includes a back support body G rotatably supported on the support base C, and a backrest H supported on the support base C by means of the back support body G in a way that allows for a tilting action.

[0042] (Back support body G) like Figure 11 As shown, the back support body G has left and right arms g1 rotatably supported on the rotation shaft J1 and a connecting plate g2 connecting the rear ends of these arms g1. The back support body G is made of metal, and the arms g1 and the connecting plate g2 are joined by welding.

[0043] The left and right arms g1 are plate-shaped arms extending in a pair along the front-rear direction, with shaft holes g3 at their front portions for the rotating shaft J1 and the synchronous shaft J2 to pass through and be fixed. The left and right arms g1 are supported so that they can rotate around the rotating shaft J1, which passes through and is fixed to the shaft hole g3. Multiple bolt holes (not shown) are provided on the rear side (back side) of the connecting plate g2 for multiple bolts (not shown). Nut portions g4 are fixed to the front side (front side) of each bolt hole by welding. Furthermore, a swing operating lever c7 is rotatably mounted on the arm g1.

[0044] (Backrest H) like Figure 12 and Figure 13 As shown, the backrest H includes a back frame h1, a back frame h2 disposed on the front side of the back frame h1, a fabric h3 tensioned on the back frame h2, a lumbar support h4 installed on the back side of the fabric h3 on the back frame h2, and a pelvic operating part h5 that positions the back frame h2 so that its position can be changed relative to the back frame h1 in the front-back direction.

[0045] The backrest H has a back frame h2, on the front side of the back frame h1, with a tensioned fabric h3, configured to be repositionable in the front-to-back direction. With this structure, the back frame h2 is easily elastically deformable, providing a soft, supportive feel to the occupant's back. The backrest H as a whole can tilt backward about a rotation axis J1 located at the support base C. Specifically, the backrest H is supported by a back support body G, allowing it to rotate about the rotation axis J1 of the support base C.

[0046] (Back frame h1) The back frame h1 is capable of tilting backward about a rotation axis J1 provided on the support base C. It includes left and right side frame portions h1a, an upper frame portion h1b spanning the upper ends of the left and right side frame portions h1a, left and right lower frame portions h1c extending forward from the lower ends of the left and right side frame portions h1a respectively, and a lower connecting portion h1d that connects and fixes the left and right lower frame portions h1c together to the connecting plate g2 of the back support body G. The left and right side frame portions h1a, upper frame portions h1b, left and right lower frame portions h1c and lower connecting portion h1d are molded from synthetic resin and assembled as a single unit.

[0047] The left and right side frame portions h1a of the back frame h1 are each shaped as members that gradually widen downwards. The side frame portions h1a of the back frame h1 are located on the inner side of the back side, which is mainly composed of fabric h3 that is tensioned and set on the back frame h2. The left and right side frame portions h1a are roughly V-shaped in both side and front views, and the upper and lower portions of the left and right side frame portions h1a are connected by a curved portion.

[0048] The upper frame portion h1b of the back frame h1 is located on the upper inner side of the back side and is a structural frame that connects the upper ends of the side frame portions h1a to each other. The upper frame portion h1b is provided with elements constituting an upper connecting portion for mounting the upper end of the back frame h2. Specifically, the front of the upper frame portion h1b has multiple recesses h1e and protrusions h1f that open forward in the left-right direction. The bottom surface of the upper frame portion h1b has bolt through holes h1g that communicate with each recess h1e.

[0049] The left and right lower frame portions h1c of the back frame h1 are connected to the left and right side frame portions h1a, and the front portion extends from the lower end of the left and right side frame portions h1a to a position corresponding to the rotation axis J1. That is, a portion of the left and right lower frame portions h1c is located outside the left and right arms g1 in the back support body G. In other words, the left and right lower frame portions h1c are formed to extend in the front-rear direction, and the front end extends to both sides of the support base C located below the seat cushion D. In addition, a second bracket h1h is erected on the lower frame portion h1c.

[0050] (Back frame h2) A back frame h2, positioned in front of the back frame h1, is mounted to the back frame h1 at its upper end and lower left and right sides. A protrusion h2a and a recess h2b are arranged on the back side of the upper end of the back frame h2 in a manner corresponding to the recesses h1e and protrusions h1f. The protrusion h2a engages with the recess h1e formed in the upper frame portion h1b of the back frame h1, and the recess h2b is used to engage with the protrusion h1f. Furthermore, on the back side of the back frame h2, engagement grooves h2c are provided at locations corresponding to the side frame portions h1a and lower frame portions h1c of the back frame h1 for engaging the fabric h3. A first bracket h2d, connected to a pelvic operating part h5, is formed on the lower left and right rear sides of the back frame h2. The pelvic operating part h5 is connected to the back frame h1. That is, the back frame h2 is movably connected to the back frame h1 via the pelvic operating part h5.

[0051] In the fabric h3 tensioned and set in the back frame h2, an attachment is sewn onto the upper edge of the fabric h3. Figure 14 The first fabric fastener h6 shown in (A) is a thin sheet of synthetic resin formed into a strip with a width similar to that of the upper end of the back frame h2. In the first fabric fastener h6, mounting portions h6a and h6b are formed at positions corresponding to the protrusion h2a and recess h2b on the back side of the upper end of the back frame h2, respectively. The mounting portions h6a and h6b have openings that match the shapes of the protrusion h2a and recess h2b. The mounting portion h6a is shaped to open towards the end edge of the first fabric fastener h6 in the width direction, and the mounting portion h6b is shaped as a through hole relative to the first fabric fastener h6.

[0052] Furthermore, a through hole h6c for the locking pin KP to pass through is formed in the central portion of the upper end of the first fabric fastener h6 located on the back frame h2. Additionally, a cutting line h6d is formed around the through hole h6c in an inverted U-shape, allowing for localized elastic deformation when the locking pin KP is inserted into the through hole h6c, thus preventing the first fabric fastener h6 from floating towards the upper end of the back frame h2. Furthermore, a [missing information - likely a type of sewn-on fastener] is installed on the outer periphery of the side portion and lower end of the fabric h3. Figure 14 The second fabric snap fastener h7 shown in (B) is used for inserting into the snap fastener slot h2c.

[0053] In this embodiment, the second fabric snap-fit ​​body h7 has a label positioning slit h7a. The label positioning slit h7a is formed to the same width as the label T. If the label T is sewn onto the fabric h3 with the label inserted into the slit h7a, the label T can be easily installed at a predetermined position on the chair A. The label T can display the manufacturer's name, brand name, or URL of a user manual animation page, advertising page, or SNS (social networking service) referral page for the chair A.

[0054] The tensioning setting of the fabric h3, which has a first fabric fastener h6 and a second fabric fastener h7 sewn along its outer perimeter, towards the back frame h2 will be explained. The back frame h2 is wrapped with the fabric h3 from the front side, as follows: Figure 15 As shown, the mounting portions h6a and h6b of the first fabric engaging body h6, located at the upper edge of fabric h3, are aligned with the protrusions h2a and h2b of the back frame h2. At this time, the mounting portion h6a enters from the upper side of the protrusion h2a. In this state, the protrusion h2a of the back frame h2 engages with the recess h1e of the back frame h1, and the recess h2b of the back frame h2 engages with the protrusion h1f of the back frame h1. The back frame h2, the first fabric engaging body h6, and the back frame h1 are then engaged using the engaging pin KP. Thus, with fabric h3 positioned by the back frame h1 and back frame h2, fabric h3 is clamped, and the upper ends of the back frame h1, back frame h2, and fabric h3 are integrated. Furthermore, the portion of the fabric h3 other than its upper end is installed by inserting the second fabric fastener h7 into the fastening groove h2c formed along the outer periphery of the back side and bottom of the back frame h2. Additionally, as previously described, the lower portion of the back frame h2 is rotatably connected to the back frame h1 via the pelvic operating part h5.

[0055] (lumbar support component h4) like Figure 16 As shown, a waist support h4 is positioned behind (on the back side) of the fabric h3, which is tensioned and set on the back frame h2. The waist support h4 is installed on the lower back side of the back frame h2 in a manner that extends along the width of the back frame h2. Figure 17As shown, the lumbar support member h4 has a retaining portion h4a that abuts against and holds the lumbar region of the seated person, and an insertion portion h4b that is narrow at both ends in the width direction. A C-shaped recess h4c is formed in the insertion portion h4b. The lumbar support member h4 is installed by inserting the insertion portion h4b into an insertion opening h2e formed in the back frame h2. A fitting protrusion (not shown) is formed on the inner side of the insertion opening h2e to engage with the recess h4c. Therefore, by inserting the insertion portion h4b into the insertion opening h2e, the recess h4c of the lumbar support member h4 engages with the fitting protrusion of the back frame h2, thus securing the lumbar support member h4 to the back frame h2 in a way that prevents it from falling off.

[0056] The waist support h4, which is mounted on the back frame h2, can be disengaged by inserting a flathead screwdriver or similar tool between the recess h4c of the waist support h4 and the mating protrusion of the back frame h2 through the insertion opening h2e. In other words, the waist support h4 can be attached to and detached from the back frame h2.

[0057] (Pelvic manipulation section h5) Next, the general structure of the pelvic operating part h5 and the general operation based on the pelvic operating part h5 will be explained. As described above, the back frame h2, on which the lumbar support member h4 is mounted, can change its position relative to the back frame h1 using the pelvic operating part h5. Figure 18 and Figure 19 As shown, the pelvic operating unit h5 includes a main body (first main body) h5a, an operating lever h5b, a stop member h5c, a coil spring h5e as a force-applying member, a first screw h5f, and a main body (second main body) h5g. Furthermore, the second bracket h1h includes a locking portion h5d. A cylindrical portion h5h and a first rotating shaft h5i are formed in the main body h5a. A gripping portion is formed in the operating lever h5b, which is perpendicular to the shaft h5j. The shaft h5j is assembled to the main body h5a by inserting it into the small-diameter side of the cylindrical portion h5h. Additionally, the shaft h5j can rotate inside the cylindrical portion h5h.

[0058] A through hole h5k is formed in the center of the stop member h5c. In this embodiment, the stop member h5c has protrusions and recesses at predetermined angles (60 degrees for example) in the circumferential direction centered on the through hole h5k. The second bracket h1h, which is provided with a locking part h5d, is erected on the lower rear side of the left and right sides of the back frame h1 with the engaging surface facing outward in the left and right directions. A through hole h5l is formed in the center of the locking part h5d. Furthermore, the locking part h5d has an engaging surface with the same shape (corresponding shape) as the stop member h5c, and is paired with the stop member h5c, allowing for protrusion-contact engagement with each other. When the engaging surfaces of the stop member h5c and the locking part h5d are engaged with each other, the through holes h5k and h5l are connected with their center points aligned on the same straight line.

[0059] The coil spring h5e and the stop member h5c are housed in the large-diameter side of the cylindrical portion h5h of the main body h5a in the order described. The stop member h5c is positioned to abut against the other end of the coil spring h5e. In this state, the stop member h5c is threadedly fixed to the threaded hole h5m of the operating lever h5b using a first screw h5f. Furthermore, the large-diameter side opening of the cylindrical portion h5h of the main body h5a is formed at the engagement surface h5n for the stop member h5c to engage with, and the stop member h5c engages with this engagement surface h5n. Additionally, the stop member h5c protrudes from the large-diameter side opening of the cylindrical portion h5h.

[0060] The main body h5a, which houses the operating lever h5b, the coil spring h5e, and the stop member h5c, is assembled so that the exposed portion of the stop member h5c engages with the locking portion h5d. Furthermore, the pelvic operating unit h5 is mounted to the back frame h1 by inserting the second rotation shaft h5o of the main body (second main body) h5g inside the through hole h5l of the locking portion h5d and threading the second screw h5p into the internal thread h5q formed in the main body h5a. The pelvic operating unit h5, thus mounted, utilizes the force of the built-in coil spring h5e to ensure that the stop member h5c is always forced towards the locking portion h5d, thus restricting accidental movement of the back frame h2 (lumbar support h4). Therefore, to change the position of the back frame h2 relative to the back frame h1, the operating lever h5b of the pelvic operating unit h5 must be rotated.

[0061] At the base of the shaft h5j of the operating lever h5b, a conical surface h5r is provided along the outer circumferential surface of the shaft h5j. Inside the cylindrical portion h5h of the main body h5a into which the shaft h5j of the operating lever h5b is inserted, conical surfaces h5s are provided at 180-degree intervals along the circumferential direction. If the operating lever h5b is rotated inside the cylindrical portion h5h, the conical surfaces h5r and h5s slide against each other, and the amount of protrusion of the operating lever h5b in the axial direction of the cylindrical portion h5h increases. As a result, the helical spring h5e is compressed, reducing the force that presses the stop member h5c against the locking portion h5d, allowing the operating lever h5b to rotate and releasing the engagement between the stop member h5c and the locking portion h5d.

[0062] Thus, if the engaging force between the stop member h5c and the locking part h5d is reduced, the stop member h5c can be rotated while the engaging surface between the locking part h5d and the stop member h5c slides, thanks to the rotation of the operating lever h5b. Consequently, the back frame h2 rotates using the shaft h5j formed in the main body h5a and connected to the first bracket h2d of the back frame h2. The pelvic operating part h5 in this embodiment can provide three positions, but the number of positions available from the pelvic operating part h5 can be appropriately varied by designing the engaging surface between the stop member h5c and the locking part h5d.

[0063] Furthermore, in the main body (second main body) h5g, at a required interval in the radial direction of the shaft h5j, a support wall h5t is erected within a required length range along the outer circumferential surface of the shaft h5j. At a predetermined position of the back frame h2 based on the pelvic operating part h5, the first bracket h2d of the back frame h2 is prevented from falling off by the support wall h5t. When removing the back frame h2 from the back frame h1 in the state where the pelvic operating part h5 is installed, the connection between the upper end of the back frame h1 and the back frame h2, which is fixed by a pin, is released, causing the upper end of the back frame h2 to tilt forward. The back frame h2 is pulled out when the forward tilt angle of the back frame h2 relative to the back frame h1 is a predetermined angle, thus releasing the anti-detachment restriction of the first bracket h2d of the back frame h2 by the support wall h5t, and the back frame h2 can be removed from the back frame h1. By setting the positional relationship between the first bracket h2d and the upright wall h5t, the back frame h2 cannot be pulled out from the back frame h1 within the normal range of use.

[0064] (Headrest X) A headrest X is detachably mounted on the upper part of the backrest H. For example... Figure 20 As shown, the headrest X has a mounting part x1 that is mounted to the backrest H and a head abutment part x2 that is rotatable about a horizontal axis extending in the left-right direction at the upper end of the mounting part x1.

[0065] like Figure 20 and Figure 21 As shown, the mounting part x1 includes a clamping part x3 that clamps the upper end of the backrest H, a slider part x4 that is held so as to slide relative to the clamping part x3 in the vertical direction, and a height adjustment mechanism x5 that adjusts the height position of the head abutment part x2 relative to the backrest H.

[0066] The clamping part x3 has a first member x3a that abuts against the upper surface of the upper end of the backrest H and a second member x3b that abuts against the lower surface of the upper end of the backrest H. When the backrest H is clamped by the first member x3a and the second member x3b, they are integrally fixed from the lower surface side of the front end by threads. A block receiving part (not shown) is formed on the back side of the first member x3a. This block receiving part is used to receive the block x5a, which is part of the height adjustment mechanism x5, and a force-applying spring x5b that applies force to the block x5a towards the slider part x4. The force-applying spring x5b and the block x5a are received in the block receiving part in the order described, and the block x5a protrudes from the front end of the block receiving part as part of the block x5a. A guide rail clamping part x3c is formed on the rear (back) side of the first member x3a along the height direction. This guide rail clamping part x3c clamps two rows of guide rails x4a that are erected along the height direction on the front side of the slider part x4 along the width direction. By clamping the guide rail x4a with the guide rail clamping part x3c, the slider part x4 can slide in the height direction.

[0067] like Figure 22 As shown, the height adjustment mechanism x5 in this embodiment includes a block x5a, a force-applying spring x5b, a cam plate x5g, an anti-detachment stop x5j, and an anti-misinstallation stop x5k. The height adjustment mechanism x5 will be described in detail below.

[0068] Block x5a is formed from synthetic resin into a block, and the block has elements of the height adjustment mechanism x5 formed on one rectangular side. A spring receiving hole x5c for receiving a force-applying spring x5b is disposed on the side of block x5a located on the clamping part x3 side. Since the depth dimension of the spring receiving hole x5c is sufficiently smaller than the length dimension of the force-applying spring x5b, even when the force-applying spring x5b is received into the spring receiving hole x5c, the force-applying spring x5b reliably protrudes from the outer surface of block x5a. A mountain-shaped portion x5d, a rib x5e, and an inclined rib x5f, which are elements of the height adjustment mechanism x5, are formed on the side of block x5a opposite to the spring receiving hole x5c.

[0069] The mountain-shaped portions x5d are disposed at both ends of the block x5a in the width direction. The inclined surfaces of the mountain-shaped portions x5d are formed to be different from each other. In this embodiment, it is an asymmetrical shape formed in such a way that the inclination angle of the upper inclined surface of the mountain-shaped portion x5d in the block x5a installed in the standard state is steeper than the inclination angle of the lower inclined surface of the mountain-shaped portion x5d. In addition, a U-shaped rib x5e is erected to fill the space between the two mountain-shaped portions x5d, opening the upper side of the block x5a. The height of the rib x5e relative to the block portion of the block x5a is fixed, and it is formed to be lower than the top height of the mountain-shaped portion x5d. In other words, the rib x5e is formed to be relatively high except for the top of the mountain-shaped portion x5d. An inclined rib x5f is erected at the middle position in the left-right direction of the rib x5e.

[0070] like Figure 20 , Figure 21 , Figure 23 and Figure 24 As shown, in the portion between the two rows of guide rails x4a on the front side of the slider part x4, two rows of cam plates x5g are erected parallel to each other along the height direction at required intervals in the left-right direction. Multiple protrusions x5h, shaped like mountains, are erected at equal intervals on the cam plates x5g, and a large protrusion x5i, higher than the other protrusions x5h, is disposed at the lower end of the cam plate x5g. In this embodiment, the inclined surface of the protrusion x5h is an asymmetrical shape formed such that the inclination angle of the lower inclined surface is greater than that of the upper inclined surface, and it engages with the mountain-shaped portion x5d of the block x5a. Furthermore, the large protrusion x5i is also formed such that the inclination angle of the lower surface inclined surface is greater than that of the upper surface inclined surface.

[0071] Furthermore, on the lower side of the cam plate x5g, anti-detachment stop members x5j are formed in directions orthogonal to the opposite cam plates x5g. At the lower end of the cam plate x5g, in the central portion of the width direction of the two rows of cam plates x5g, an anti-misinstallation stop member x5k is erected parallel to the anti-detachment stop member x5j. The height of the anti-detachment stop member x5j is formed to be the same as the height of the cam plate x5g at the same height position. The anti-misinstallation stop member x5k is formed to be sufficiently low compared to the protrusion height of the protrusion x5h.

[0072] This describes the installation method for mounting block x5a onto cam plate x5g. If block x5a is in its standard state (with the opening of rib x5e facing upwards), and the mountain-shaped part x5d slides on the cam surface of cam plate x5g, then due to the opening of rib x5e and the inclined surface of inclined rib x5f, it can slide upwards onto cam plate x5g without interfering with the anti-misinstallation stop x5k and anti-disengagement stop x5j. For example... Figure 23 and Figure 24As shown, since the convex portion x5h constituting the cam surface can engage with the mountain-shaped portion x5d, if the force of the applied spring x5b is overcome and the block x5a slides on the cam surface, the block x5a engages with the convex portion x5h at the arrangement intervals, accompanied by a click sensation. By selecting the engagement position of the block x5a, the amount of protrusion of the slider portion x4 from the clamping portion x3 (the height position of the head abutting portion x2) can be selected. Figure 25 As shown, the block x5a, which is installed on the cam plate x5g in the standard state, has its bottom surface x5l, which is formed as a flat surface, abutting against the anti-detachment stop x5j, so that the block x5a will not fall off the slider part x4.

[0073] Conversely, if the mountain-shaped part x5d slides on the cam surface of the cam plate x5g while the block x5a is in a non-standard state (the opening of the rib x5e faces downwards), then as... Figure 26 As shown, before the mountain-shaped part x5d mounts onto the cam surface of the cam plate x5g, the bottom side wall surface x5m of the rib x5e abuts against the anti-misinstallation stop x5k, restricting the movement of the block x5a. This prevents the block x5a from entering the cam surface of the cam plate x5g, thus preventing the clamping part x3 from being mistakenly installed onto the slider part x4.

[0074] like Figure 27 and Figure 28 As shown, the head abutment part x2 includes a frame x6 and a fabric x7. As shown in the two rear side perspective views, the frame x6 has a fabric holding frame x6a that holds the fabric x7 and a decorative frame x6b mounted on the rear (back) side of the fabric holding frame x6a. A connecting part x6c that connects to the slider part x4 is disposed on the fabric holding frame x6a. This connecting part x6c can adopt a known structure, so its description is omitted here. A tongue x6d is provided around the outer periphery of the fabric holding frame x6a on the back side. A gap exists between the tongue x6d and the fabric holding frame x6a, in which the outer periphery of the fabric x7 (the third fabric engaging part x7b and the fourth fabric engaging part x7c) is accommodated (see reference). Figure 29 ).

[0075] like Figure 30 As shown, in this embodiment, the fabric x7 is sewn along the outer periphery of the fabric body x7a to attach a third fabric fastener x7b and a fourth fabric fastener x7c. The third fabric fastener x7b is a known structure formed as a thin sheet made of simple synthetic resin. Figure 31As shown, the fourth fabric clasp x7c has X-shaped through holes x7d formed at fixed intervals along its length, and has cutouts x7e arranged aligned with the center portions of each through hole x7d. The cutouts x7e are formed independently of the through holes x7d from both ends of the fourth fabric clasp x7c in the width direction toward the inside of the width direction.

[0076] Furthermore, in the central portion of the fourth fabric clasp x7c in the width direction, through holes x7d are formed at fixed intervals along the length direction, but the inner end of the cut portion x7e in the width direction does not reach the predetermined width range based on the center line in the width direction. Therefore, a relatively large amount of board portion (unprocessed portion) remains in the central portion of the fourth fabric clasp x7c in the width direction. As a result, more seam allowance can be provided when sewing the fourth fabric clasp x7c to the fabric body x7a. In addition, the cut portion x7e of the fourth fabric clasp x7c has a large amount of material removed in the length direction at both ends in the width direction, making it prone to deformation with external force. Thus, the fourth fabric clasp x7c can provide more seam allowance and reduce the unfolding of the fabric body x7a, resulting in a shape that is easily deformed.

[0077] By employing such a fourth fabric tack assembly x7c, the fourth fabric tack assembly x7c can stretch and compress together with the fabric body x7a in the length direction of the fourth fabric tack assembly x7c. Figure 31 (B) and (C)). Furthermore, it can be bent in the same plane relative to the length direction of the fourth fabric card assembly x7c. Figure 31 (D) Utilizing these features of the fourth fabric fastener x7c, even for curved sections with small curvature that the second fabric fastener h7 cannot handle, the fourth fabric fastener x7c can easily deform, thus enabling it to follow the curved section. Using such a fourth fabric fastener x7c, the fabric body x7a and the fourth fabric fastener x7c are fastened together to the gap between the fabric holding frame x6a and the tongue x6d. Therefore, even with long-term use, the undesirable situation of the fabric body x7a being exposed from the fabric holding frame x6a can be reliably avoided.

[0078] In addition, in this embodiment, such as Figure 30 As shown, a third fabric clip x7b and a fourth fabric clip x7c are installed along the outer periphery of the fabric body x7a, but it is also possible to install only the fourth fabric clip x7c. In short, as long as the third fabric clip x7b or the fourth fabric clip x7c can be engaged with the gap between the fabric retaining frame x6a and the tongue x6d along the entire outer periphery of the fabric body x7a, it is acceptable.

[0079] (Handrail Y) In this embodiment, the seat cushion D of chair A is detachably equipped with armrests Y. Figure 32 and Figure 33 As shown, the armrest Y in this embodiment includes a seat cushion mounting part y1, a height adjustment cylinder y2, a sliding cylinder y3, an elbow support y4, an operating lever y5, and a height position holding part y6.

[0080] The seat cushion mounting part y1 has a seat cushion fixing part y1a and a cylindrical part y1b, which are L-shaped by the seat cushion fixing part y1a and the cylindrical part y1b with an open upper surface. A screw hole y1c extending vertically is provided in the seat cushion fixing part y1a. The seat cushion is mounted to the seat cushion D by aligning the screw hole y1c with a threaded hole (not shown) formed on the lower surface of the seat cushion D, and by using a screw y1d fastened from the lower surface of the screw hole y1c. The upper surface of the cylindrical part y1b is open, and the cylindrical part y1b houses the height adjustment cylinder y2 and the sliding cylinder y3 in an assembled state. The cylindrical part y1b and the height adjustment cylinder y2 are fixed by a known method.

[0081] In this embodiment, the height adjustment cylinder y2 is shaped such that the portion of the desired height range has been cut off from the bottom half of the front side. On the rear circumferential surface y2a of the height adjustment cylinder y2, a plurality of through holes y2b are provided at fixed intervals along the height direction. Figure 34 It is evident that two through holes y2b are configured such that the ribs y2c, which extend along the height direction, are sandwiched from the left and right directions at the same height position. Furthermore, the ribs y2c protrude from the front side of the rear circumferential surface y2a. A sliding cylinder y3 is inserted into the height adjustment cylinder y2 in a pluggable manner.

[0082] The sliding cylinder y3 has a cylindrical portion y3a into which the height adjustment cylinder y2 is inserted, and a shell-shaped elbow support portion y3b that supports the elbow support y4. A front groove y3d extending in the height direction is formed on the front peripheral surface y3c of the cylindrical portion y3a. A rear groove y3f extending in the height direction is formed on the rear peripheral surface y3e of the cylindrical portion y3a. Furthermore, an opening y3g is formed at the lower part of the rear peripheral surface y3e, in a configuration that divides the rear groove y3f. The cylindrical portion y3a of the sliding cylinder y3, thus formed, is inserted into the height adjustment cylinder y2 with the rib y2c engaged with the rear groove y3f.

[0083] The height position holding part y6 has a main body y6a, a locking claw y6b, and a force-applying spring y6c. A locking piece y6d is formed on the front of the main body y6a, and the locking piece y6d engages with a groove y3d formed on the front of the sliding cylinder y3. Furthermore, the force-applying spring y6c and the locking claw y6b are arranged in the order described above on the rear of the main body y6a. That is, the force of the force-applying spring y6c, which is positioned between the locking claw y6b and the main body y6a, applies force to the locking claw y6b in a direction protruding from the rear of the main body y6a. The height position holding part y6, thus formed, is received through a lower opening of the sliding cylinder y3. Moreover, the height position holding part y6 is positioned and fixed to the sliding cylinder y3 with the locking piece y6d engaging with the front groove y3d and the locking claw y6b protruding from the opening y3g of the sliding cylinder y3. Therefore, as mentioned above, if the sliding cylinder y3 is inserted into the height adjustment cylinder y2, the sliding cylinder y3 is fixed to the height adjustment cylinder y2 in such a state that the engaging claw y6b engages with the two through holes y2b located at the same height and the rib y2c enters the rear groove y3f.

[0084] Thus, the height-holding part y6, which is installed on the sliding cylinder y3 and engages with the height-adjusting cylinder y2, is connected to the operating lever y5 via the metal wire y7. More specifically, the operating lever y5 is connected to the engaging pawl y6b via the metal wire y7. That is, if the user rotates the operating lever y5, the engaging pawl y6b slides in the opposite direction to the force applied by the force-applying spring y6c via the metal wire y7. By rotating the operating lever y5, the engaging state between the engaging pawl y6b and the through hole y2b of the height-adjusting cylinder y2 is released. By lifting the elbow support part y3b while the operating lever y5 is rotated, the user can pull a portion of the sliding cylinder y3 up from the height-adjusting cylinder y2.

[0085] like Figure 34 As shown, the elbow support y4 is composed of an elbow support portion y21 formed by the overlapping of a first path body y4a and a first retaining body y4b in the vertical direction, and an elbow support body y22 formed by the overlapping of a second path body y4c, a second retaining body y4d, and an elbow support pad y4e in the vertical direction. The elbow support body y22 can slide relative to the elbow support portion y21 in the front-back direction. A guide groove y4m is formed on the rear side of the elbow support body y22, and the fixed shaft N2, which is fixed to the elbow support portion y21, enters the guide groove y4m. A guide groove y4j is formed on the front side of the elbow support portion y21, and the movable shaft N1, which is a stepped screw, of the nut retaining portion y4n of the elbow support y4 enters the guide groove y4j.

[0086] The first path body y4a has: a main body y4g having an opening y4f; an island forming body y4h having a planar region smaller than the opening y4f in the central portion; and a retainer y4i for holding the island forming body y4h in a state of floating in the central portion of the planar region of the opening y4f. As shown, the main body y4g and the island forming body y4h form an annular (approximately mouth-shaped) guide groove y4j. The retainer y4i is formed in an approximately U-shape to avoid the planar position of the guide groove y4j within a desired height range.

[0087] Furthermore, a resistance-applying body y4k is disposed within a portion of the circumferential length of the inner circumferential surface of the opening y4f of the first retainer y4b. The resistance-applying body y4k is configured to protrude inward toward the guide groove y4j of the other party, thereby narrowing a predetermined portion of the guide groove y4j. The resistance-applying body y4k is formed in the first retainer y4b as a spring-like body with a π-shaped top view, but is not limited to this configuration; for example, it may also be formed from an elastic material. Alternatively, the resistance-applying body y4k may not be formed in the first retainer y4b, but rather in the first path body y4a. The width of the guide groove y4j within the range where the resistance-applying body y4k is disposed is smaller than the width of the guide groove y4j within the range where the resistance-applying body y4k is not disposed. Furthermore, when the movable shaft N1 enters the configuration range of the resistance applying body y4k in the guide groove y4j of the other side, the outer peripheral surface of the movable shaft N1 elastically deforms the resistance applying body y4k while passing through the configuration range of the resistance applying body y4k. Therefore, the resistance during movement is greater compared to other ranges. In this embodiment, the first path body y4a and the first retaining body y4b are formed separately and are engaged integrally by the engaging piece y4l formed on the first retaining body y4b. However, the first path body y4a and the first retaining body y4b can also be formed integrally.

[0088] The second path body y4c has the following on its rear side: a guide groove y4m, which is S-shaped; a nut retainer y4n that retains a nut N1a, the nut N1a being threadedly connected to a movable shaft N1 that enters and moves within the guide groove y4m; and an opening y4o and a mounting part y4p for mounting the operating lever y5. The guide groove y4m is formed in a top-view S-shape, configured such that its initial direction from rear to front is substantially consistent with the direction of either of the annular sections in the other guide groove y4j. This allows the elbow support body y22, composed of the second path body y4c, the second retainer y4d, and the elbow support pad y4e, to move on an S-track that can move in both the front-rear and left-right directions. Furthermore, on the fixed shaft N2 entering the guide groove y4m, an O-ring N2b is disposed between it and a washer N2a. The washer N2a is formed to have a width larger than the width of the guide groove y4m and is supported on the upper surface of the guide groove y4m. When the shaft portion N2c of the fixed shaft N2 moves within the guide groove y4m, the elastic deformation of the O-ring N2b prevents vertical wobbling between it and the second path body y4c.

[0089] A nut N1a is housed in a fixed state in the nut retaining part y4n, and the nut N1a is threadedly fixed by an external thread formed on the narrow diameter portion of the movable shaft N1. An O-ring N1c is disposed between the nut N1a and the washer N1b, and sliding resistance is applied by the elastic deformation of the O-ring N1c generated when the movable shaft N1 rotates around the guide groove y4j on the other side.

[0090] An opening y4o is provided through the front peripheral surface of the second path body y4c. The grip portion y5a of the operating lever y5 passes through the opening y4o. The mounting portion y4p is formed as a plate-like body having an opening that engages with the rotation shaft y5b of the operating lever y5, and is erected on the upper surface of the second path body y4c in a manner aligned with the two ends of the rotation shaft y5b along its length. The opening y4o is formed to the height required for the operating lever y5 to rotate within a predetermined angle range in the vertical direction. Because a thick-walled portion y5c is formed at the base of the grip portion y5a of the operating lever y5 to close the gap between the opening y4o and the grip portion y5a, foreign objects are prevented from entering through the gap between the operating lever y5 and the opening y4o.

[0091] The second retainer y4d is formed in a flat plate shape. Multiple engaging tabs y4r are formed on the outer periphery of the second retainer y4d, and these engaging tabs y4r engage with engaging portions y4q formed on the second path body y4c. By engaging the engaging tabs y4r of the second retainer y4d with the engaging portions y4q of the second path body y4c, the upper surface of the second path body y4c becomes closed, preventing foreign objects from entering the second path body y4c. Furthermore, the elbow support pad y4e is mounted removably on the upper surface of the second retainer y4d using a known method.

[0092] As previously described, the operating lever y5 is rotatably mounted on the second path body y4c. A wire engagement part y5d is provided on the rotation axis y5b of the operating lever y5, and the first end of the wire y7 is connected to the wire engagement part y5d. The wire y7 is pulled from one guide groove y4m of the second path body y4c into the interior of the sliding cylinder y3, and the second end is connected to the engagement claw y6b of the height position holding part y6. Thus, by transmitting the rotational motion of the operating lever y5 to the height position holding part y6 via the wire y7, the operating lever y5 can be positioned on the elbow rest y4e (second path body y4c), which can move forward, backward, left, and right. Furthermore, by using one guide groove y4m for manipulating the wire y7 in the elbow rest y4, bending of the wire y7 can be reduced, and the operating lever y5 can be operated smoothly regardless of the position of the elbow rest y4e.

[0093] like Figure 35 and Figure 36 As shown, when the elbow rest body y22 moves from rear to front, it initially moves in an S-shape along the guide groove y4m located on the rear side. Meanwhile, the movable shaft N1, which moves along the other guide groove y4j with the elbow rest body y22, reaches the portion (front end face) in the other guide groove y4j where the resistance-applying body y4k is located, and experiences resistance. When the elbow rest body y22 moves from front to rear, it can move through either side of the annular shape of the other guide groove y4j located on the front side. Thus, by making the other guide groove y4j annular, the occupant can experience multiple movement paths of the elbow rest body y22. Furthermore, since the movable shaft N1, which moves along the guide groove y4j on the other side together with the elbow support body y22, moves from the part in the guide groove y4j where the resistance application body y4k is arranged to the part where the resistance application body y4k is not arranged, there is a sense of resistance at the beginning of the movement, and then it can move without any sense of resistance.

[0094] The path width of the area where the resistance-applying body y4k is disposed in the guide groove y4j on the other side is narrower than the path width of other parts. When the movable shaft N1 passes through this area, it passes through while being pushed aside by the outer periphery of the movable shaft N1. In this way, by causing the resistance-applying body y4k to elastically deform, a sense of resistance to movement can be applied to the movable shaft N1, which makes the chair A feel more luxurious, and allows the occupant to easily identify the current position of the elbow rest y4 and the direction of the next movement. In addition, in this embodiment, sliding resistance is applied due to the elastic deformation of the O-ring N1c generated when the movable shaft N1 rotates around the guide groove y4j on the other side. Therefore, resistance to movement of the movable shaft N1 can be applied by simply arranging either the O-ring N1c or the resistance-applying body y4k.

[0095] like Figures 35-37 As shown, in this embodiment, when the elbow support body y22 moves from rear to front, it follows the S-shaped guide groove y4m, which becomes the movement trajectory of the front end of the elbow support body y22 first moving outward and then gradually moving inward. When moving from front to rear, it can also pass through the annular arbitrary path of the other guide groove y4j. Therefore, it can provide a variety of movement modes that are different from the simple back-and-forth movement track of the elbow support body y22 in the prior art.

[0096] The structure of chair A using the present invention has been described above, but the technical scope of the present invention is not limited to the above embodiments. In the above embodiments, the description is based on the example of the synchronous shaft J2 as the rotation shaft and the example of the seat support d1 as the rotating body, but the present invention can be applied even to rotation shafts other than the synchronous shaft J2 and rotating bodies other than the seat support d1.

[0097] Furthermore, any combination of the methods described in this specification can be used as an embodiment of the present invention. Explanation of reference numerals in the attached figures

[0098] A: Chair B: Chair legs b1: Caster wheel; b2: Chair leg blade; b3: Chair leg support. C: Support base c1: Mounting hole; c2: Reaction spring; c3: Reaction spring support; c4: Chain plate. c5: elongated hole; c6: swing force adjustment rod. c7: Swing control lever D: Seat cushion d1: Seat cushion support (rotating body), d2: Seat cushion body, d3: Cushion, d4: Recess. d5: Protrusion, d6: Shaft receiving hole, d7: Opening. d8: Spring retainer, d9: Spring, d10: Press plate d10a: Upper protrusion, d10b: Front protrusion. d11: Synchronous shaft mounting part (connection part). d11a: Inclined convex part (inclined surface forming body). d11b: Arc-shaped abutment part (abutment part), d12: Opening hole, d12a: First engaging recess, d12b: Second engaging recess (engaging recess). d12x: inner peripheral surface, d13: stopper, d13a: upper part, d13b: Inclined part, d13c: Rear protrusion (protrusion to prevent positional deviation). Rear protrusions d13c, d13d: engaging claws; d13e: lower protrusion. d13f: Synchronous shaft mating part F: Backrest structure G: Back support body g1: Arm, g2: Connecting plate, g3: Shaft hole, g4: Nut part H: Backrest h1: Back frame, h2: Back frame, h3: Fabric, h4: Lumbar support h5: Pelvic operating section; h6: First fabric clasp assembly. h7: Second fabric clasp J1: Rotary shaft, J2: Synchronous shaft (rotating shaft), J3: Locking shaft J4: Shaft T: Tag X: Headrest x1: Mounting part, x2: Head contact part, x3: Clamping part x4: Slider section, x5: Height adjustment mechanism, x6: Frame, x7: Fabric Y: Handrail y1: Seat cushion mounting section, y2: Height adjustment cylinder, y3: Sliding cylinder, y4: Elbow rest. y5: Operating lever, y6: Height position holding part, y7: Metal wire y21: Elbow support section; y22: Elbow support body 10: Seat cushion support and synchronous shaft connection structure (rotating body connection structure).

Claims

1. A rotating body connection structure, wherein rotating bodies are connected to form a structure that allows rotation along the outer circumferential surface of a rotation axis, characterized in that, The rotating body is provided with a connecting portion that connects the lower surface of the rotating body to the upper surface, and an abutting portion for the rotating shaft to be inserted from the lower surface side of the connecting portion to abut against. An opening that communicates with the communicating portion is formed on the upper surface of the rotating body. A stop body that is movably fitted with the outer peripheral surface of the rotating shaft and serves to prevent the rotating shaft from falling off the rotating body is detachably mounted in the opening.

2. The rotating body connecting structure according to claim 1, characterized in that, The opening is located in a different plane from the abutment portion.

3. The rotating body connecting structure according to claim 1 or 2, characterized in that, The connecting portion is provided with an inclined surface forming body that is inclined in a front-back direction from the lower surface of the rotating body toward the upper surface of the rotating body, and the opening hole is formed as a reverse inclined hole that is inclined in the opposite direction to the inclined surface formed by the inclined surface forming body.

4. The rotating body connecting structure according to claim 1 or 2, characterized in that, A locking recess is formed in the opening, and the locking recess is offset from the rear side surface formed on the upper part of the stop body to prevent locking by a protrusion.

5. The rotating body connecting structure according to claim 3, characterized in that, The stop body has an engaging claw that engages with a portion of the inner circumferential surface of the reverse inclined hole.

6. A chair capable of synchronously swinging, causing the seat cushion and backrest to tilt and move in conjunction, via a rotating shaft, characterized in that, The rotating shaft is located at the front of the backrest. The seat cushion is provided with a connecting portion that connects the upper surface and the lower surface of the seat cushion, and an abutting portion for the rotating shaft to be inserted from the lower surface side of the connecting portion. A stop body that is movably fitted with the outer peripheral surface of the rotating shaft and used to prevent the rotating shaft from falling off the cushion is detachably installed in the opening hole, the opening hole communicating with the communicating portion and opening on the upper surface of the cushion.

7. The chair according to claim 6, characterized in that, The opening is located in a different plane from the abutment portion.

8. The chair according to claim 6 or 7, characterized in that, The connecting portion is provided with an inclined surface forming body that is inclined in a front-to-back direction from the lower surface of the cushion toward the upper surface of the cushion, and the opening hole is formed as a reverse inclined hole that is inclined in the opposite direction to the inclined surface formed by the inclined surface forming body.

9. The chair according to claim 6 or 7, characterized in that, A locking recess is formed in the opening, and the locking recess is offset from the rear side surface formed on the upper part of the stop body to prevent locking by a protrusion.

10. The chair according to claim 8, characterized in that, The stop body has an engaging claw that engages with a portion of the inner circumferential surface of the reverse inclined hole.

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