Chair

Abstract

To provide a chair pleasantly performing seat depth adjustment while a person is still seated.SOLUTION: A chair includes a rotary handle 60 as seat depth adjustment means. A slider 66 moves rightward or leftward when a screw shaft 65 is rotated by the handle 60, and a link 36 rotates by the slider 66. An effector 27 is connected to the inner edge of the link 36, and the front edge of the effector is connected to the front edge part of the seat. Even when longitudinally external force is applied to the effector 27, the external force is applied so as to make the slider 66 move rightward or leftward. However, even when the slider 66 moves rightward or leftward, the screw shaft 65 does not rotate, so that a longitudinal position of the seat is maintained in a set condition even when a lock mechanism is not installed.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present invention relates to a chair in which the front end of the seat can be rolled down. [Background technology]

[0002] As a technique for adjusting the front-to-back length of a seat (depth of the front end) in a chair, there is a method of rolling the front part of the seat downward, as disclosed in Patent Document 1, for example. One method for adjusting the seat depth is to move the entire seat back and forth, but this method has the problem of imposing a burden on the user as the user must lift their hips when adjusting the seat back and forth, whereas the rolling-up method as disclosed in Patent Document 1 has the advantage of being easy to operate as it can be operated while remaining seated.

[0003] In addition, because the seat except for the front part that is allowed to deform is fixed to the seat support member, there is also the advantage that the support structure of the seat can be simplified. Also, since the upper surface of the seat is generally recessed to match the profile of the human buttocks and is designed so that the body is supported by the backrest with the buttocks fitting into the recess in the seat, there is a risk that the fit between the recess in the seat and the human buttocks will be impaired if the entire seat moves forward or backward, whereas with the rolling-in method as in Patent Document 1, the front-to-back position of the recess in the seat does not change, there is an advantage that the fit is not impaired and it is comfortable to use. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2015-171653 A Summary of the Invention [Problem to be solved by the invention]

[0005] In Patent Document 1, a forward-backward moving lever is used as a means for adjusting the depth by rolling up and returning the deformable portion of the seat. The lever is connected to a forward-backward moving actuator that is connected to the front end of the deformable portion, and the forward-backward movement of the lever moves the actuator back and forth, thereby rolling up and returning the deformable portion of the seat.

[0006] The method of Patent Document 1 is sufficiently practical and has been highly evaluated in the market, however, it is anticipated that some people may find it difficult to perform fine adjustments by moving the lever back and forth. Therefore, it can be said that there is a latent demand for technology that allows fine adjustments to be performed reliably and easily.

[0007] Furthermore, since the rolling up of the seat when the front end of the seat is moved back is performed by deforming the deformable parts of the seat (the inner shell and the seat cushion material) against elasticity, there is resistance when rolling up the seat, and therefore the rolling up of the seat should be performed with as little force as possible. As a cushioning material for seats, etc., there is a three-dimensional net structure made by intertwining and joining a group of elastic resin fibers, which is suitable as a seat cushioning material because it has excellent breathability, durability, and recyclability, but this three-dimensional net structure has a higher elastic resistance than the polyurethane foam that is widely used as a cushioning material for chairs, so when this is used for a chair, it can be said that there is a particularly high demand for a light rolling up operation.

[0008] The present invention has been made to improve this current situation. [Means for solving the problem]

[0009] The present invention includes various configurations, typical examples of which are specified in each claim. The invention of claim 1 is as follows: "A seat having a front portion that can be rolled downward as a deformation-permitting portion, and an adjustment device that is manually operated by a person to wind up or release the deformation-permitting portion, The adjustment device has a handle that can be rotated by a user while seated, and an interlocking mechanism that transmits the rotation of the handle to the deformation-allowing part. The structure is as follows.

[0010] The invention of claim 2 is an example of the development of claim 1. "The portion of the seat that is not the deformable portion is attached to a seat support member disposed below the seat support member, and an actuator whose front end is connected to the front end of the deformable portion is attached to the seat support member as a part of the interlocking mechanism so as to be movable forward and backward. The handle is supported on a side of the seat support member so as to rotate about a left-right longitudinal axis, The interlocking mechanism has a slider that moves left and right in conjunction with the rotation of the handle, and the left and right movement of the slider is converted into forward and backward movement of the actuator. The structure is as follows.

[0011] The invention of claim 3 is an example of the development of claim 2, "The interlocking mechanism is rotated by the handle and includes a screw shaft that is screwed into the slider." The structure is as follows.

[0012] The invention of claim 4 is a development example of claim 2 or 3, "The interlocking mechanism is provided with a release means for causing the handle to spin freely when a predetermined resistance acts on the handle when the handle is rotated in the direction of releasing the deformable portion." The structure is as follows.

[0013] The invention of claim 5 is also an example of the development of claim 2 or 3. "The seat has an inner shell made of synthetic resin and a seat cushion material stretched on the upper surface of the inner shell, and the deformation-permitting portion is formed in the inner shell and the seat cushion material, The seat cushion material has a three-dimensional net-like structure in which a group of elastic fibers made of synthetic resin are intertwined and bonded, and the actuator is biased in the backward direction by a spring. The structure is as follows.

[0014] The invention of claim 6 is also an example of the development of claim 2 or 3. "The portion of the seat that is not the deformation-allowing portion is attached to the seat support member, and a bearing bracket penetrating in the left-right direction is fixed to one or both of the left and right sides of the seat support member with a bolt, The interlocking mechanism including the handle and the screw shaft is assembled to the bearing bracket to form a unit. The structure is as follows.

[0015] The invention of claim 7 is also an example of the development of claim 2 or 3. "The slider and the actuator are connected by a link mechanism that is horizontally rotatable." As an example of the development of claim 7, claim 8 is as follows: "The operating body is attached to the seat receiving member so as to be movable forward and backward, The actuator and the slider are connected by a single link, and the link is inclined in a plan view so that one end connected to the slider is located behind the other end connected to the actuator, and when the slider moves inward, the actuator moves forward. The following configuration is adopted.

[0016] In addition, this application discloses many novel structures that have not been seen before, and these novel structures can be claimed as independent claims in themselves, for example, the spring specified in claim 5 and the links specified in claims 7 and 8 can be claimed as independent claims in themselves. In this case, the seat cushion material is not necessarily limited to a three-dimensional net-like structure, and urethane foam resin, etc. are also included. Effect of the Invention

[0017] In the present invention, the roll-in method is characterized in that the user can adjust the seat depth while remaining seated without lifting their hips, but since the handle is rotatable and the amount of force applied can be adjusted as desired, there is no problem of applying too much force and rolling in or out too much, and the seat depth can be precisely adjusted to the desired state.

[0018] Also, as can be easily understood from the example of the handle that adjusts the elasticity of the backrest elasticity adjustment spring, even if the handle is turned greatly, the forward and backward movement distance of the actuator is small, so that the seat depth can be easily adjusted even if the elastic restoring force of the seat is high. As mentioned above, when a three-dimensional net structure made of resin elastic fiber is used as the seat cushion material, the elastic restoring force is high, but even in this case, the seat depth can be adjusted with a light force.

[0019] The elastic restoring force of the seat acts as an external force that moves the operating body forward, but when the operating body is connected to a slider that moves left and right as in claim 2, the forward external force acting on the operating body almost never acts as an external force that moves the slider backward. Therefore, even without providing a locking means, it is possible to prevent or significantly suppress the phenomenon in which the deformation-permitting portion of the seat returns to its original shape and the front end position of the seat moves forward.

[0020] By adopting a configuration in which the slider moves left and right on the screw shaft as in claim 3, the slider can be moved left and right with a simple structure. Also, when a person's foot hits the front end of the seat and a backward external force acts on the operating body, or conversely, a forward external force acts on the operating body due to the elastic restoring force of the deformation allowance part, an external force in the front-back direction may act on the operating body, but when a screw shaft is used as in claim 3, a force acts on the slider that tries to move it in the axial direction of the screw, so the screw shaft does not rotate naturally and the front-back position of the seat does not change.

[0021] In addition, the seat can be maintained in an adjusted state even if the lead angle is increased by using a multiple start thread, etc. Therefore, the left and right movement distance of the slider per one turn of the handle can be increased, allowing the seat depth to be adjusted quickly.

[0022] Now, because the deformable portion of the seat is trying to return in the winding release direction, the handle can be rotated in the return direction of the deformable portion with a light force, but if the operating body moves all the way forward and the handle suddenly stops from its momentum, there is a risk of damage to the components due to the impact. In contrast, with the configuration of claim 4, even if the seat moves all the way forward, the handle does not suddenly stop but continues to spin freely, preventing damage to the components.

[0023] In addition, when the seat rotates in the direction that winds up the deformable portion, the handle is subjected to rotational resistance, so that the handle is heavy, so that no impact is applied even if the actuator is fully retracted and the handle stops rotating. Therefore, there is no need to allow the handle to spin freely when rotating in the direction that winds up the deformable portion, and conversely, the handle needs to be rotated without spinning freely.

[0024] As mentioned above, using a three-dimensional mesh structure made of entangled resin elastic fibers as a seat cushion material is useful in terms of breathability, etc., but there is a problem in that it has a strong elastic restoring force and therefore high resistance to rolling up. However, by adopting the configuration of claim 5, the operating body is biased in the backward direction by a spring, so that the seat depth can be adjusted easily with little force, even if the seat cushion material has a three-dimensional mesh structure.

[0025] In addition, the spring acts as a resistance against the seat returning to its original position, preventing the seat from naturally returning to its original position due to the repulsive force of the deformation-permitting portion, and further preventing the seat from returning to its original position without resistance when the seat is released from the winding.

[0026] Since the seat depth adjustment device is composed of a fair number of parts, it would take a great deal of time to assemble them individually into the chair, and there is concern that errors in assembly could lead to variations in quality. In addition, parts management would also be a hassle. In contrast, if the screw shaft, handle, etc. are assembled into the bearing bracket as in claim 6 and made into a unit in advance, it would not only be possible to assemble it quickly into the chair, which would improve production efficiency, but it would also stabilize quality and reduce the time and effort required for parts management.

[0027] Using a link mechanism as a means for converting the left-right movement of the slider into the forward-backward movement of the actuator as in claim 7 allows for accurate transmission of movement while simplifying the structure. In this case, using a single link to transmit power as in claim 8 is preferable as it further simplifies the structure. [Brief description of the drawings]

[0028] [Figure 1] 1A is a front perspective view of a chair according to an embodiment, FIG. 1B is a side view, and FIG. 1C is a rear perspective view of the chair according to an embodiment. [Diagram 2] 1A is a perspective view of the seat cushion material separated, and FIG. 1B is a perspective view of the lower part of the seat inner shell separated. [Diagram 3] 1A and 1B are exploded perspective views of the main part, in which (A) is a view from above and (B) is a view from below. [Figure 4] 1A is a bottom view of the seat inner shell, and (B) and (C) are perspective views of the seat cushion material. [Diagram 5] 1A is a perspective view of the seat outer shell with the actuating body attached, and FIG. 1B is a separated perspective view of the actuating body and the seat outer shell. [Figure 6] 4A and 4B are perspective views of the seat inner shell and the actuator when separated from each other, where FIG. 4A is a view of the seat inner shell as viewed from above, and FIG. [Figure 7] 1A is a separated perspective view of the actuating body and the seat outer shell, (B) is a separated plan view showing the overlapping state of the actuating body and the seat outer shell (the actuating body has been flipped over front to back), (C) is a partial perspective view of the actuating body, and (D) is a plan view of the seat outer shell. [Figure 8] 1A is a perspective view of the main parts separated as viewed from above, FIG. 1B is a perspective view of the main parts separated as viewed from below, FIG. 1C is a perspective view showing the ratchet rotor in particular, and FIG. 1D is a cross-sectional view taken along the line DD of FIG. [Figure 9]1A is a plan view of the main parts, (B) is a separated perspective view of the main parts seen from the outside, (C) is a separated perspective view of the main parts seen from the inside, (D) is a separated plan view of the main parts, and (E) is a separated plan view of some components. [Figure 10] FIG. [Figure 11] FIG. [Figure 12] FIG. 11 is a perspective view of a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] Next, an embodiment of the present invention will be described with reference to the drawings. This embodiment is applied to the seat of a swivel rocking chair that is widely used for office work. In this application, terms such as "front / back" and "left / right" are used to specify directions, but these are based on the direction of a person sitting in a normal posture. A front view is the direction facing a person sitting. With regard to inside / outside, the left / right middle side is considered to be inside, and the left / right side is considered to be outside.

[0030] (1) Basic structure of chair and seat First, an overview of the chair will be described mainly with reference to Figures 1 to 3. As shown in Figure 1, the chair to which this embodiment is applied is a swivel chair that is often used in offices, and the chair comprises, as basic elements, a leg device 1, a seat 2, and a backrest 3. The leg device 1 has a structure in which a leg support 4 made of a gas cylinder is erected in the center of a base having five leg blades, and a caster is provided at the tip of each leg blade.

[0031] A base 5 is fixed to the upper ends of the leg supports 4, and left and right first tilting frames 6 and a second tilting frame 7 are connected to the base 5, and an upper back frame 8 is attached to these tilting frames 6, 7. The first tilting frame 6 also serves as the lower back frame, and a back panel 3a is attached to the upper and lower back frames 8 to form the backrest 3. The back panel 3a is covered with upholstery 3b from the front.

[0032] As shown in Fig. 1(B), the front end of the first tilting frame 6 is connected to the base 5 by a main shaft 9. Therefore, the backrest 3 tilts backward with the main shaft 9 as a fulcrum. As shown in Figs. 2(B) and 3(A), a seat outer shell 10 made of synthetic resin is disposed above the base 5 as an example of a seat support member. The seat outer shell 10 has a shell structure with a shallow recess facing downward.

[0033] As shown in FIG. 3, for example, a lateral extension arm 11 located below the rear of the seat outer shell 10 is formed integrally with the first tilting frame 6, and a rear bearing portion 12 provided on the seat outer shell 10 is connected to the tip of the lateral extension arm 11 by a left-right long pin 13.

[0034] On the other hand, as shown in Fig. 3(A), left and right joint mounts 14 are protrudingly provided at the front portion of the base 5, and left and right front support parts 15 provided at the front portion of the seat outer shell 10 are supported and connected to these joint mounts 14. The upper surface of the joint mounts 14 is curved upward in side view, and the front support parts 15 are supported in a state where they can slide smoothly and move. Therefore, when the first tilting frame 6 tilts backward and the backrest 3 reclines, the seat outer shell 10 and the seat 2 supported thereby tilt backward while moving backward.

[0035] As shown in Fig. 2, the seat 2 has a seat inner shell 16 made of synthetic resin and a seat cushion material 17 stretched on the inner shell, and the seat cushion material 17 is attached to the seat outer shell 10. The seat cushion material 17 is covered from above with an upholstery (skin) not shown.

[0036] (2) Seat and seat outer shell As shown in Figures 4(A) and 5, a plurality of (five) horizontally long slits 20 are formed in an area near the front of the seat inner shell 16. Therefore, the area of ​​the seat inner shell 16 having the horizontally long slits 20 serves as a deformable portion 16a that can be rolled up downward. The portion of the seat inner shell 16 behind the deformable portion 16a serves as a wide base portion 16b that does not deform, and the portion in front of the deformable portion 16a serves as a narrow front rigid portion 16c that does not deform.

[0037] When the pair of left and right joint brackets 21 protruding downward from the front rigid portion 16c are pulled backward, the deformable portion 16a is rolled downward together with the front portion of the seat cushion material 17. This allows the front-rear position of the front end of the seat 2 to be adjusted. Therefore, the area of ​​the seat 2 having the horizontal slit 20 serves as the deformable portion 2a.

[0038] The horizontal slits 20 of the seat cushion material 17 extend over the entire length from left to right, and the area between adjacent horizontal slits 20 forms a belt-like portion 22 that is U-shaped and opens downward when viewed from the side, and the adjacent belt-like portions 22 are connected by a lower bridge 23 at the areas near both left and right ends.

[0039] The band-shaped portion 22 at the rear end is connected to the base portion 16b by a lower bridge 23, and the band-shaped portion 22 at the front end is connected to the front rigid portion 16c by a lower bridge 23. Therefore, the deformation-permitting portion 16a is composed of a group of band-shaped portions 22 and a group of lower bridges 23. As shown in Fig. 5(A), notches 24 are formed in the band-shaped portions 22 at the left and right outer portions of the lower bridges 23 in a plan view. Therefore, deformation of each band-shaped portion 22 is facilitated.

[0040] As shown in Figures 4(A) and 6(B), a group of downward engaging claws 25 for fixing the upholstery is formed on the underside of the outer periphery of the inner shell. Although only a portion of them is shown in Figure 9, an edge member 26 made of a resin tape is sewn or welded to the periphery of the upholstery, and the edge member 26 is fitted and attached to the engaging claws 25. Therefore, the edge member 26 has engaging holes.

[0041] 5, the seat outer shell 10 has a bottom 10a, left and right inclined wall portions 10b, and a rear wall portion 10c, and is in the form of a tray that is open upward and forward, and a resin actuator 27 is placed on top of the inside of this seat outer shell 10. The actuator 27 is in the form of a plate with reinforcing ribs, and basically has a left and right width that overlaps the bottom 10a of the seat outer shell 10, but has wing portions 29 that overlap the inclined guide portions 28 of the seat outer shell 10 on both the left and right sides of the front half.

[0042] A pair of left and right side guide ribs 31 are formed on the bottom 10a of the seat outer shell 10 to sandwich the rear part of the actuator 27 from the left and right, and the side guide ribs 31 are provided with anti-slip pieces 32 that overlap the rear side edges of the actuator 27 from above. Therefore, the rear part of the actuator 27 is held by the side guide ribs 31 so as not to shift laterally or to slip upward.

[0043] Also, a front guide rib 33 having an L shape in front view with an upper end formed as an inward horizontal piece is formed in the front part of the bottom 10a of the seat outer shell 10, while a long slot 34 long in the front-rear direction into which the front guide rib 33 fits is formed in the underside of the actuating body 27 as shown in Fig. 6(B), and a retaining piece 35 is formed in the front-rear midway part of this long slot 34, located below the inward horizontal piece of the front guide rib 33. Therefore, the actuating body 27 is held by the front guide rib 33 so that its front part does not shift sideways and cannot come off.

[0044] A link 36 (described later) is disposed on the right side of the seat outer shell 10, and as shown in FIG. 6(B) a link insertion space 37 is formed in the actuator 27 located above the long slot 34, and as shown in FIG. 5(B) and FIG. 11, the front end (inner end) of the link 36 is connected to the plate portion above the link insertion space 37 via a screw 38, a washer 39, and a bearing ring 40.

[0045] Furthermore, as shown in FIG. 5(B), a two-stage square base 44 having upper and lower two stages of outward facing pieces 43a, 43b is provided on the left and right outer sides of the front guide rib 33 of the bottom 10a of the seat outer shell 10, while as shown in FIG. 6(B), a long guide hole 42 long in the front-to-rear direction is provided on both the left and right sides of the actuator 27, and the lower stage of the square base 44 with the outward facing piece 43b is positioned on the upper edge of the long guide hole 42.

[0046] Therefore, the actuating body 27 is guided in its forward and backward movement by the square base 44, while the lower outward piece 43b prevents it from coming off the seat outer shell 10. As shown in Fig. 6(B), a wide insertion hole 45 is continuous with the rear end of the guide elongated hole 42, and when attaching the actuating body 27, the insertion hole 45 is fitted into the square base 44 and then slid backward.

[0047] The actuator 27 is biased rearward by a tension spring 46 disposed on its right side. For this reason, as shown in Fig. 5(B), a rear spring hook 47 is formed on the rear part of the bottom 10a of the seat outer shell 10, to which the rear end of the tension spring 46 is engaged, and a front spring hook 48 is formed on the underside of the front end of the actuator 27, to which the front end of the tension spring 46 is hooked.

[0048] The portion of the seat inner shell 16 behind the deformation-permitting portion 16a is fixed to the seat outer shell 10. First, as shown in Fig. 2(A) and Fig. 4(A), the bottom portion 10a of the seat outer shell 10 is formed with side downward bosses 49 for resting on the seat outer shell 10, and front downward bosses 50 on the left and right longitudinal sides that engage with the above-mentioned rectangular base 44 so as not to be able to turn upward. The front downward bosses 50 rest on the lower stage of the rectangular base 44 and engage with the outward pieces 43a of the upper stage.

[0049] Furthermore, a pair of downward bosses 51 that come into contact with the bottom 10a of the seat outer shell 10 are formed on the left and right sides of the rear part of the seat inner shell 16, and screws inserted into the seat outer shell 10 from below are screwed into the downward bosses 51. Therefore, the base of the seat inner shell 16 is fixed at its rear part to the seat outer shell 10 with screws, with its front part held by the square pedestal 44 of the seat outer shell 10 so as not to move left or right and not to come off upward.

[0050] 6, a pair of left and right joint members 52 provided at the front end of the actuator 27 are connected to the joint bracket 21 provided on the seat inner shell 16. That is, the joint bracket 21 is formed in a gate shape with an opening when viewed from the front, while the joint member 52 has a recess 54 into which the lower part of the joint bracket 21 fits and a hook portion 55 that engages with the opening of the joint bracket 21, and the joint bracket 21 is held in the recess 54 of the joint member 52 so as not to be able to move up and down with the hook portion 55 engaged with the opening.

[0051] For this reason, when the joint member 52 and the actuating body 27 move back and forth, the joint bracket 21 moves back and forth, and the deformable portion 16a of the seat inner shell 16 and the seat cushion material 17 are rolled in and out. The actuating body 27 moves back and forth by rotating the handle 60 shown in FIG.

[0052] FIG. 10 shows the cross section of the seat cushion material 17, which is made of a three-dimensional net-like structure made by entangling and bonding a large number of elastic and winding resin fibers such as polyester fibers. Therefore, it has a breathable structure similar to that of nonwoven fabric. In this case, the seat cushion material 17 is made of a tough base layer 17a made of thick fibers and a soft surface layer 17b made of fine fibers densely entangled, and both are heat-sealed together. Because of the two-layer structure, it is soft to the touch of the user's body and has high elasticity and durability. The seat cushion material 17 bends and deforms together with the deformable portion 16a of the seat inner shell 16. Therefore, in the front part of the seat 2, there is a deformable portion 2a corresponding to the deformable portion 16a of the seat inner shell 16.

[0053] (3) Seat depth adjustment mechanism Next, the seat depth adjustment mechanism (device) will be described. The entire depth adjustment mechanism is shown in a separated form in Figures 9(B) and (C). As shown in these figures, the depth adjustment device includes a handle 60 that is rotated by a person seated on the seat, a ratchet rotor 61 partially fitted into the handle 60 from the inside, a bearing bracket 62 into which the ratchet rotor 61 is partially fitted from the outside, an intermediate member 63 partially fitted into the bearing bracket 62 from the inside, an inner member 64 completely inserted into the intermediate member 63 from the inside, a screw shaft 65 disposed inside the intermediate member 63, and a nut-type slider 66 screwed onto the screw shaft 65, and the outer end of the link 36 is connected to the slider 66.

[0054] In this embodiment, the ratchet rotor 61, the intermediate member 63, the inner member 64, the screw shaft 65, the slider 66, and the link 36 form an interlocking mechanism.

[0055] A hexagonal head 67 is fixed to the outer end of the screw shaft 65, and the head 67 is fitted into a hexagonal frame portion 63a formed at the inner end of the intermediate member 63. Therefore, the intermediate member 63 and the screw shaft 65 rotate together. A pocket portion 69 that holds a nut 68 is formed at the upper end of the hexagonal frame portion 63a, and a screw 70 inserted into the pocket portion 69 is screwed into the nut 68, and the screw 70 is further fitted into the head 67 of the screw shaft 65. Therefore, the screw shaft 65 is held so as not to come off from the intermediate member 63. The inner end of the screw shaft 65 is rotatably held by a bearing portion 71 (see, for example, FIG. 5) provided at the front end of a side guide rib 31 formed on the seat outer shell 10.

[0056] The slider 66 has a forward protruding portion 66a that is circular in plan view, and as shown in Figure 11, for example, the forward protruding portion 66a and the outer end of the link 36 are connected by a screw 38, a washer 39, and a bearing ring 40. The bearing ring 40 is for smoothing rotation, and a positioning protrusion 75 on the underside fits into an engagement hole 76 opened in the link 36.

[0057] The screw 38 is screwed into the link 36. The washer 39 abuts against the upper end of the bearing ring 40, and the height of the cylindrical portion of the bearing ring 40 is slightly greater than the thickness of the forward protruding portion 66a of the slider 66. Therefore, the slider 66 and the link 36 rotate smoothly relative to each other about the vertical axis. The relationship between the inner end of the link 36 and the left-right intermediate portion 27a of the actuator 27 is similar. The inner end of the link 36 is connected to the front end portion of the actuator 27, the left-right intermediate portion 27a (see FIG. 6(A)).

[0058] 9(B) and (C), the inner member 64 has a hollow structure with a flange 64a, and a straight cut-out hole 77 is formed in the cylindrical portion. The inward surface of the intermediate member 63 has an intermediate diameter portion 63b with a smaller diameter than the intermediate frame portion 63, and the bearing bracket 62 has a stepped hole 78 into which the intermediate diameter portion 63b fits.

[0059] A pressing rod 79 is inserted from the outside into the handle 60. A flange 80 is fixed to the outer end of the pressing rod 79, while a recess 81 into which the flange 80 fits is formed in the outer end face of the handle 60, and the flange 80 is fixed to the bottom surface of the recess 81. Therefore, the pressing rod 79 rotates integrally with the handle 60.

[0060] The rod 79 passes through the ratchet rotor 61 and the intermediate member 63, and its tip is fitted into the inner member 64. A pair of fins 82 are formed at the tip of the rod 79, and the fins 82 are fitted into the cut holes 77 in the inner member 64. In this state, the inner member 64 is fixed to the rod 79 with screws 83. Therefore, the inner member 64 rotates integrally with the handle 60. The ratchet rotor 61, bearing bracket 62, and intermediate member 63 are held by the handle 60 and the inner member 64 so that they cannot be separated from each other.

[0061] The ratchet rotor 61 has a portion that fits into the intermediate member 63, and this portion is provided with a pair of fins 84, while the intermediate member 63 is formed with a cut groove 85 into which the fins 84 fit. Therefore, the ratchet rotor 61, the intermediate member 63, and the screw shaft 65 rotate integrally.

[0062] 8(A) and (D), the handle 60 is formed with a circular hollow hole 87 into which the ratchet rotor 61 is partially fitted, and its inner peripheral surface is an uneven surface 88 consisting of a series of triangular peaks and valleys. On the other hand, the portion of the ratchet rotor 61 that fits into the handle 60 is formed with a pair of guide portions 89 that come into sliding contact with the uneven surface 88, and a pair of engaging spring portions 90 that fit into and disengage from the uneven surface 88 against elasticity. The engaging spring portions 90 are in the shape of a pocket with a free tip, and an elastic shaft 91 made of rubber or the like is attached inside.

[0063] Therefore, the engaging spring portion 90 fits onto and disengages from the concave-convex surface 88 against the combined elastic force of its own elastic restoring force and the elastic axis 91. Conversely, the handle 60 can be rotated idly in one direction against the elasticity of the engaging spring portion 90 and the elastic axis 91.

[0064] Furthermore, the engaging spring portion 90 has its tip as a free end facing in the counterclockwise rotation direction shown by the solid-line arrow in FIG. 8(D). Therefore, when the handle 60 is rotated clockwise in the direction of the dotted-line arrow, if the ratchet rotor 61 is in a state of stopping rotation, the engaging spring portion 90 will fall and deform, causing the handle 60 to rotate idly. Conversely, when the handle 60 is rotated counterclockwise in the direction of the solid line, the engaging spring portion 90 presses against the peak of the concave-convex surface 88 of the handle 60, so the handle 60 cannot be rotated idly.

[0065] As shown in FIGS. 8(A) and 8(B), a bulging portion 92 that bulges downward and enters inward is formed on the left inclined wall portion 10b of the seat outer shell 10, and a bearing bracket 62 is superposed on the bulging portion 92 from the outside. The bearing bracket 62 is fixed to the inclined wall portion 10b by two front and rear screws 93.

[0066] For example, as shown in FIG. 11, a nut insertion hole 61a is opened on the inward-facing front surface of the bearing bracket 62, and the screw 93 is screwed into a nut attached to the nut insertion hole 61a. As shown in FIG. 8(A), a hole 94 through which the intermediate member 63 can pass is provided in the bulging portion 92. As shown in FIGS. 8(B) and 8(C) and FIGS. 9(B) and 9(C), the inner end portion 60a of the handle 60 is formed to have a slightly smaller diameter so as to partially enter the bearing bracket 62.

[0067] (4). Summary In the above configuration, the screw shaft 65 is held by the intermediate member 63 and the bearing portion 71 so as not to move left or right, but can only rotate. Since the ratchet rotor 61, intermediate member 63, and screw shaft 65 rotate together, when the handle 60 is rotated, the screw shaft 65 rotates and the slider 66 moves back and forth, which in turn rotates the link 36 horizontally and moves the operating body 27 back and forth, thereby winding and releasing the seat inner shell 16, and the depth of the seat 2 can be adjusted.

[0068] To be precise, if the screw shaft 65 is a right-handed screw, rotating the handle 60 to the left moves the slider 66 forward inward, reeling in the seat 2, and rotating the handle 60 to the right moves the slider 66 backward, unreeling the seat 2.

[0069] When a person's feet hit the front end of the seat 2 from the front and a backward external force acts on the seat 2, an external force that moves the slider 66 back outward acts on the slider 66 via the link 36, and conversely, when an external force that moves the actuator 27 forward acts on the actuator 27 due to the elastic restoring force of the seat cushion material 17 and the seat inner shell 16, an external force that moves the slider 66 inward acts on the slider 66 via the link 36, but because the actuator 27 hits the threads of the screw shaft 65 from the left and right (axial direction), the screw shaft 65 does not rotate. Therefore, the depth of the seat 2 is maintained at the desired adjusted position.

[0070] In other words, the external force in the fore-and-aft direction acting on the actuator 27 acts as an axial thrust force on the threads of the screw shaft 65. Therefore, even if an external force in the fore-and-aft direction acts on the actuator 27, the rotational effect on the screw shaft 65 is extremely small, and there is no risk of the screw shaft 65 rotating naturally and causing a change in the depth of the seat 2.

[0071] In particular, when the slider 66 and the actuator 27 are connected by the link 36 as in the embodiment, the external force caused by the rotation of the link 36 acts to push the slider 66 toward the axial center of the screw shaft 65, so that even if a very large force is applied to the link 36, the pushing action of the link 36 will not cause the screw shaft 65 to rotate. Therefore, even without providing a locking mechanism, the seat 2 has a high function of being able to hold the adjusted state.

[0072] As mentioned above, the three-dimensional mesh structure made of resin elastic fiber used in the seat cushion material 17 has a high restoring force (repulsion force), so there is a large resistance to the rolling up of the deformable portion 2a of the seat 2. However, by arranging the tension spring 46 that biases the actuator 27 in the backward direction as in the embodiment, the deformable portion 2a can be rolled up with a light force.

[0073] If the repulsive force of the seat cushion material 17 is very large, depending on the conditions, it is possible that the screw shaft 65 will spin freely and the reeling will be released naturally. However, by providing the tension spring 46 as in the embodiment, the seat cushion material 17 can be held in a reeled state by the tension spring 46, so that the front end of the seat 2 can be prevented from moving forward naturally even if the repulsive force of the seat cushion material 17 is high. In addition, when the handle 60 is operated in the reeling release direction, the rotation is too light and the seat 2 overruns from the desired position. A compression coil spring can also be used as the biasing means. Alternatively, it is possible to bias the link 36 in the inward rotation direction by using a torsion spring.

[0074] As described above, when the handle 60 is rotated left, the operating body 27 advances, and when the handle 60 is rotated right, the operating body 27 retreats, but as already described, the handle 60 can rotate freely with respect to the ratchet rotor 61 when rotated right, but cannot rotate freely when rotated left. Therefore, even if resistance is exerted against the winding of the deformable portion 2a, particularly from the seat cushion material 17, winding can be reliably performed by rotating the handle 60. On the other hand, since an internal stress acts on the deformable portion 2a to promote release of the winding, the handle 60 can be released from the winding without rotating freely.

[0075] Now, because the deformation-permitting portion 2a of the seat 2 is attempting to return in the direction of releasing the winding, the handle 60 can be rotated with a light force in the direction moving the front end of the seat 2 forward. However, since it is not possible to visually check whether the seat 2 has fully advanced, if the handle 60 and the screw shaft 65 were unable to rotate relative to each other, when the handle 60 was being rotated in the direction moving the seat 2 forward and the actuator 27 had fully advanced, the rotation of the handle 60 would suddenly stop from its momentum, and the impact could damage the components.

[0076] In contrast, if the handle 60 is configured to be able to rotate freely in the direction in which the seat 2 is advanced, as in the embodiment, the handle 60 will not suddenly stop but will rotate freely even when the seat 2 is fully advanced, so that the components will not be damaged. Also, the handle 60 will rotate freely and generate a clicking sound, allowing the user to know that the seat 2 has been fully advanced. Therefore, the ratchet rotor 61 and the uneven surface 88 function as a safety device to prevent damage to the components.

[0077] On the other hand, when the handle 60 is rotated in a direction to wind up the deformable portion 2a of the seat 2, a rotational resistance is acting, so that the handle 60 is in a heavy state, so that no impact is applied even if the operating body 27 is fully retracted and the rotation of the handle 60 stops. Therefore, there is no need to allow the handle 60 to spin freely in the direction to wind up the deformable portion 2a, and conversely, the handle 60 needs to transmit the rotation firmly to the screw shaft 65 without spinning freely.

[0078] As shown in Figure 11, the components constituting the depth adjustment mechanism, except for the slider 66 and the link 36, are integrated with the bearing bracket 62 as the core component. That is, the handle 60, screw shaft 65, etc. are assembled to the bearing bracket 62 to form a single unit. This significantly reduces the effort required for managing components during transportation and storage, and also eliminates assembly errors to stabilize quality.

[0079] In the second embodiment shown in Fig. 12, an auxiliary link 36a is provided. That is, in Fig. 12, first, reference numeral 95 denotes a first base plate, reference numeral 96 denotes a second base plate, and reference numeral 97 denotes a third base plate, and a side frame portion 98 long in the front-rear direction is fixed to the side portion of each of the base plates 95-97, and these base plates 95-97 and the side frame portion 98 form a seat receiving member, and the depth adjustment mechanism members such as the handle 60 and the screw shaft 65 are disposed in the side frame portion 98.

[0080] The actuator 27 is formed in a plate shape and is attached to the first base plate 95 by a long guide hole 99 extending in the front-rear direction and a T-shaped guide body 100 so as to be able to slide freely back and forth. The slider 66 and actuator 27 are connected by a link 36, and the middle part of the link 36 and the second base plate 97 are connected by an auxiliary link 36a.

[0081] As can be seen from a comparison of FIG. 12 with, for example, FIG. 7(D), the link 36 of the first embodiment is in a position that is largely reclined toward the left-right longitudinal line compared to the link 36 of the second embodiment (when the slider 66 is fully advanced, the inclination angle of the link 36 with respect to the left-right longitudinal line is about 15°). Therefore, the component of the forward-backward external force acting on the actuator 27 that causes left-right movement is much smaller in the first embodiment. Therefore, it is possible to reliably prevent the screw shaft 65 from rotating due to a backward or forward external force acting on the actuator 27. The inclination angle of the link 36 with respect to the left-right longitudinal line is preferably about 10 to 30°.

[0082] More specifically, since the screw shaft 65 will not rotate naturally even if the lead angle of the screw shaft 65 is increased, the lead angle can be increased by using a multiple thread, for example, to increase the forward / backward movement dimension of the actuator 27 per unit angle of rotation of the handle 60. In other words, the depth of the seat 2 can be adjusted with as small an angle of rotation as possible.

[0083] In Fig. 10, the edge member 26 fixed to the upholstery is connected to the rigid part 16c of the seat inner shell 16, but as shown in Fig. 4(A), since the engagement claws 25 are also provided on the front end of the base 16b, it is also possible to engage the edge member 26 with the engagement claws 25 of the base 16b and cover the deformation-permitting parts 2a, 16a from below with the upholstery. In this way, even if the fibers of the seat cushion material 17 break during winding and unwinding, generating fragments, the fragments can be received by the upholstery and prevented from falling to the floor.

[0084] Although the embodiment of the present invention has been described above, the present invention can be embodied in various other ways. The screw shaft may be a multiple-start screw such as a double-start screw. Alternatively, the means for converting the rotation of the handle into the forward and backward movement of the actuating body is not limited to a combination of a slider and a link, and a gear mechanism such as a combination of a rack and pinion or a combination of a bevel gear pair may also be used. When a link mechanism is used, it is also possible to use a bell crank type or a parallel link type.

[0085] The seat cushion can be made of urethane foam. A nude seat cushion can also be used. The present invention can also be applied to a seat with a mesh material stretched over a frame that opens at the top and bottom (in this case, the front part of the frame can be configured to bend downward). [Industrial Applicability]

[0086] The present invention can be embodied in a chair, and therefore has industrial applicability. [Explanation of symbols]

[0087] 2nd seat 2a Deformable section 10 Seat outer shell (seat support material) 16 seat inner shell 16a Deformation allowance section 16b base 16c Rigid part 17 Seat cushion material 27 Actuator 36 Links that make up the interlocking mechanism 46 Tension spring as an example of a spring 60 Handle 61 Ratchet rotor that constitutes the interlocking mechanism 62 Bearing bracket 63 Intermediate member constituting the interlocking mechanism 64 Inner member that constitutes the interlocking mechanism 65 Screw shaft that constitutes the interlocking mechanism 66 Slider that constitutes the interlocking mechanism 88 Uneven surface 90 Engagement spring part

Claims

1. A seat having a front portion that is a deformable portion that can be rolled downward; and an adjustment device that is manually operated by a person to wind up or release the deformation-permitting portion, The adjustment device has a handle that can be rotated by a user while seated, and an interlocking mechanism that transmits the rotation of the handle to the deformation allowing portion. chair.

2. a portion of the seat that is not the deformation-allowing portion is attached to a seat support member disposed thereunder, and an actuator having a front end connected to a front end portion of the deformation-allowing portion is attached to the seat support member as a part of the interlocking mechanism so as to be movable forward and backward; The handle is supported on a side of the seat support member so as to rotate about a left-right longitudinal axis, The interlocking mechanism has a slider that moves left and right in conjunction with the rotation of the handle, and the left and right movement of the slider is converted into forward and backward movement of the actuator.

2. The chair according to claim 1.

3. The interlocking mechanism is rotated by the handle and includes a screw shaft screwed into the slider. A chair as claimed in claim 2.

4. The interlocking mechanism is provided with an escape means for causing the handle to rotate freely when a predetermined resistance acts on the handle when the handle is rotated in a direction to release the deformation allowance portion. A chair as claimed in claim 2 or 3.

5. The seat has an inner shell made of synthetic resin and a seat cushion material stretched on an upper surface of the inner shell, and the deformation-allowing portion is formed in the inner shell and the seat cushion material, The seat cushion material has a three-dimensional net-like structure in which a group of elastic fibers made of synthetic resin are intertwined and bonded, and the actuator is biased in the backward direction by a spring. A chair as claimed in claim 2 or 3.

6. A portion of the seat that is not the deformation-allowing portion is attached to the seat support member, and a bearing bracket penetrating in the left-right direction is fixed to one or both of the left and right side portions of the seat support member by a bolt, The interlocking mechanism including the handle and the screw shaft is assembled to the bearing bracket to form a unit. A chair as claimed in claim 2 or 3.

7. The slider and the actuator are connected by a link mechanism that is horizontally rotatable. A chair as claimed in claim 2 or 3.

8. The actuating body is attached to the seat receiving member so as to be movable forward and backward, The actuator and the slider are connected by a single link, and the link is inclined in a plan view so that one end connected to the slider is located behind the other end connected to the actuator, and when the slider moves inward, the actuator moves forward. A chair as claimed in claim 7.

Images