chair

Abstract

To provide a structure capable of stably rotating a seat without rattling even without a margin in upper and lower spaces, in a chair obtained by fitting the seat to a leg device such as a rod leg type in a horizontally rotatable manner.SOLUTION: A base 5 is fixed to the top end of the leg device, and the center hole 15 of a seat receiver 6 is fitted to the center shaft 34 provided in the base 5. The center shaft 34 has a sleeve 39 closely fitted via a bush 38 in a rotatable manner, and the seat receiver 6 is closely fitted to the sleeve 39 so as not to be rotatable relatively. The sleeve 39 is pressed and held from above via a thrust bearing 41 and a disc spring washer 42. As the sleeve 39 is pushed strongly from above and does not fall, a seat 2 is rotatable horizontally without rattling even when the center shaft 34 is short.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a chair in which the seat rotates horizontally while the leg device does not have a rotating shaft like a rod leg and is not a gas cylinder type.

Background Art

[0002] There are various types of chairs. From the perspective of the structure of the leg device, it can be roughly classified into a type in which the leg post is composed of a gas cylinder and the seat height can be adjusted (for example, Patent Document 1), and a type in which the seat height cannot be adjusted like a so-called pipe chair (for example, FIGS. 10 and 11 of Patent Document 2).

[0003] In a chair in which the leg post is composed of a gas cylinder, usually, the seat or the seat receiver is fixed to the outer cylinder constituting the gas cylinder, and the seat rotates by the rotation of the outer cylinder with respect to the inner cylinder. However, in Patent Document 1, the outer cylinder constituting the gas cylinder is non-rotating. Therefore, while a shaft cylinder is fitted to the upper end of the gas cylinder, a bearing cylinder that fits from the outside through a bush is fixed to a mounting base (seat receiver) that supports the seat. The bearing cylinder is supported by a flange provided at the lower end of the shaft cylinder, and a C-ring for preventing the bearing cylinder from coming off is fastened to the upper end of the shaft cylinder.

[0004] Among FIGS. 10 and 11 of Patent Document 2, the legs are of a four-leg type and the seat does not rotate horizontally. However, Patent Document 3 discloses that in a chair having four rod legs, the seat is horizontally rotatably supported by the legs via a large-diameter thrust bearing. In this Patent Document 3, the thrust bearing has a structure in which a large number of balls are arranged between an upper plate and a lower plate. [[ID=***]]

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

[0006] Chairs that do not have gas cylinders, such as the type of chair shown in Figures 10 and 11 of Patent Document 2 and the type of chair shown in Patent Document 3, often do not have casters and are widely used in homes, shops, offices, etc. Because they do not have casters, they can be easily used on hardwood floors, making them suitable for use with a table when working from home.

[0007] However, when used with a table, it is inconvenient to have to move the chair backward or forward each time you sit down or get up. Therefore, Patent Document 3 describes a design in which the seat can rotate horizontally to facilitate sitting down and getting up.

[0008] In chairs with leg mechanisms such as a four-legged system, the problem when rotating the seat horizontally is to stably support the seat in a space with limited vertical space. In this regard, by using a thrust bearing with a large diameter, as in Patent Document 3, the seat can be stably supported in a way that prevents it from tipping over, while remaining close to the leg members.

[0009] On the other hand, Patent Document 2 allows a single type of seat to be shared between a leg device consisting of a gas cylinder and a leg device with a four-legged configuration. However, if a large thrust bearing disclosed in Patent Document 3 is used, the leg member and the seat must have a dedicated structure, which presents a problem in that it becomes difficult to standardize components such as the seat.

[0010] The present invention was made against this backdrop, and aims to disclose a technology that enables stable horizontal rotation of the seat in a chair having a seat and legs positioned by a central axis and a central hole, with a compact structure. [Means for solving the problem]

[0012] The present invention teeth, "The leg device comprises a base fixedly attached to the leg device and a seat positioned on the base, wherein a central axis that serves as the horizontal rotation center of the seat is projected upward from the base, and a central hole is formed in the seat or the seat support that receives it, into which the central axis fits from above." A chair in which the seat or seat support is mounted to the base so as to be horizontally rotatable via a tipping prevention member that maintains the load acting on the seat so as to act exclusively in the vertical direction. In, "The central axis is straight and has the same outer diameter." The aforementioned anti-tilting member comprises a sleeve rotatably fitted tightly onto the central axis, a thrust bearing superimposed on the sleeve, and a bolt that holds and secures the thrust bearing. The outer diameter of the sleeve is formed on a tapered surface that narrows towards the top, The central hole of the seat or seat support is formed in a tapered shape that narrows towards the top, so as to fit the sleeve non-rotatably. It possesses the following characteristics.

[0013] Claim 2 The invention is claimed 1 This is an example of its development, "The sleeve is rotatably held via a bush that is in close contact with the central shaft, The thrust bearing is held in place by the bolt via an elastic ring that elastically deforms in the vertical direction. This claim has the following features. 2 As a preferred example of the invention, 3 So, the elastic ring teeth It is made of spring washers. While spring washers come in various structures, flat washers have the same shape all around, which allows for equalization of the pressing force and makes them suitable for use.

[0016] As a specific example of a thrust bearing, 「 Upper lace and lower lace Overlapping directly or through a lubricant」 The structure of Can be hired is as follows.

Advantages of the Invention

[0017] In the present invention, basically, while allowing the horizontal rotation of the seat by the fitting relationship between the central hole and the central axis, the anti - toppling member can horizontally rotate the seat in a stable posture where toppling is prevented. Therefore, the usability of a non - gas cylinder type chair provided with a seat or a seat receiver having a central hole can be improved.

[0018] When the structure of claim 1 is adopted as the anti - toppling member, since the anti - toppling member is within the range overlapping the central hole in plan view, the anti - toppling structure can be significantly compacted. Moreover, since the outer peripheral surface of the sleeve and the central hole are tapered surfaces, they can be tightly fitted (press - fitted) without play. Moreover, since the sleeve is pressed from above by the thrust bearing, the horizontal rotation of the seat can be performed smoothly while reliably preventing toppling.

[0019] When the thrust bearing is pressed from above by an elastic ring as in claim 2 , since the state where the sleeve is pressed by the thrust bearing can be firmly maintained, the anti - toppling function can be significantly improved.

[0020] Although an elastic ring that compresses and deforms, such as hard rubber, can be used, when a spring washer such as a dish - shaped one is used as in claim 3 , since commercially available products can be used as they are, it is advantageous in terms of cost. In addition, since a large elastic force can be applied, it is also suitable in terms of ensuring the pressing function.

[0021] This is shown as an example.As shown above, using a ring-shaped rotating support as a fall prevention member allows the load acting on the seat to be distributed over a wide area, thus reliably preventing the seat from falling over. In this case, since the ring-shaped rotating support is positioned to surround the central axis and central hole, it does not take up space and compactness is not compromised.

[0022] While ring-shaped thrust bearings with multiple balls can also be used, Already mentioned Adopting a design in which the upper and lower ring bodies directly overlap, as shown above, is preferable because it can reduce costs. Grease is suitable as a lubricant. [Brief explanation of the drawing]

[0023] [Figure 1] The diagram shows the external appearance of the chair according to the embodiment, where (A) is a perspective view seen from the front and above, (B) is a front view, and (C) is a perspective view seen from the front and below. [Figure 2] (A) is a separated perspective view seen from above, and (B) is a partially separated perspective view seen from below. [Figure 3] This is a separated perspective view from the same direction as Figure 2(A). [Figure 4] This is a perspective view showing the main components separated. [Figure 5] Figure 4 is a longitudinal cross-sectional front view as seen from the VV viewing direction. [Figure 6] This is a reference example of a longitudinal front view, specifically the VI-VI cross-sectional view in Figure 7(A). [Figure 7] (A) is a separated plan view of the ring-shaped rotational aid, and (B) is a partial cross-sectional view of (A) as seen from the BB viewing direction. [Modes for carrying out the invention]

[0024] Next, embodiments of the present invention will be described based on the drawings. In the following, the concepts of front / back and left / right will be used to specify directions, but these directions are based on the view from a person normally seated in a chair. The front view direction is the direction opposite to the seated person.

[0025] (1) Overview of the chair First, the chair's outline will be described primarily with reference to Figures 1 and 2. As shown in Figure 1, the chair comprises, as basic elements, a leg assembly 1, a seat 2, and a backrest 3. The leg assembly 1 consists of four rod legs 4, and as shown in Figures 1(C) and 2(B), a circular, upward-opening, dish-shaped base 5 is fixed to the upper ends of the four rod legs 4. An inward-facing portion 4a is bent and formed at the upper end of each rod leg 4, and this inward-facing portion 4a penetrates the base 5 and is welded to the base 5 from the inside of the base 5.

[0026] As shown in Figure 1(C), a seat support 6, which is roughly rectangular in bottom view (and top view), is fixed to the upper surface of the base 5. As shown in Figure 2(A) (see also Figure 3), an intermediate member 7 is mounted on the seat support 6 so as to be able to move back and forth, and the seat 2 is fixed to the intermediate member 7. The seat 2 has a structure in which a cushioning material 9 is stretched over a seat plate (seat inner shell) 8 and covered with a surface material, and the seat plate 8 is attached to the intermediate member 7 by claw engagement. The base 5 is a sheet metal product, the seat support 6 is, for example, an aluminum die-cast product, and the seat plate 7 is, for example, a molded product of synthetic resin. The seat plate 8 is mounted on the seat support 6 so as to be able to slide back and forth.

[0027] The chair has an upper support frame 10 positioned higher than the seat 2, surrounding the sitter from behind and to the sides, and the backrest 3 is attached to the upper support frame 10. The upper support frame 10 is supported by left and right side supports 11 which are fixed to the seat support 6. The backrest 3 can rotate forward and backward at a certain angle using the upper support frame 10 as a pivot point.

[0028] A grip 12 is attached to the upper end of the side support column 11, giving the appearance of an upper support frame 10 extending forward. The chair of this embodiment is basically the same as that described in Patent Document 2, and can share components with a chair having a gas cylinder type leg device. However, in a chair with a gas cylinder type leg device, the lock of the gas cylinder can be released by rotating the grip 12.

[0029] In this embodiment, when a seated person leans back against the backrest 3, the upper support frame 10 first tilts backward relative to the side support 11, performing a first stage of rocking. Then, when the upper body is bent backward, the backrest 3 tilts backward relative to the upper support frame 10, performing a second stage of rocking. Also, when a seated person leans back against the backrest 3, the seat 2 moves forward against the spring.

[0030] (2) Structure of the seat Next, the structure of the seat will be explained, mainly with reference to Figure 3. The seat support 6 has a shallow tray-like shape that is roughly rectangular in plan view and opens upwards. A central hole (mounting hole) 15 for attaching to the base 5 is located approximately in the center of the seat support 6. To ensure the height of the central hole 15, a downward-facing boss portion (cylindrical portion) 16 is formed on the seat support 6. The inner circumferential surface of the central hole 15 is a tapered surface that narrows in diameter towards the top.

[0031] As shown in Figure 3,2(A), numerous slits 17 are formed side by side in the front portion of the seat inner shell 8, and therefore the front portion of the seat 2 can rotate downward against the elasticity of the seat inner shell 8. Accordingly, as shown in Figure 3, a spring 18 that supports the front portion of the seat inner shell 8 is arranged at the front of the intermediate member 7.

[0032] As shown in Figure 3,2(A), a large rectangular opening 19 is formed in the center of the intermediate member 7 in plan view. The intermediate member 7 also has a shallow tray-like shape, and numerous reinforcing ribs extending vertically and horizontally are formed inside.

[0033] As already mentioned, the intermediate member 7 is mounted on the seat support 6 so as to be able to slide back and forth. As a means of sliding, first, as shown in Figure 3, front elongated holes (not shown) are formed on both the left and right sides of the front of the intermediate member 7, extending from front to back and through vertically. The flanged front guide shaft 21, which is inserted through these front elongated holes, is fixed to the seat support 6 by screws 22.

[0034] Furthermore, as shown in Figure 3, downward-facing bearing pieces 23 are provided on the left and right side edges of the opening 19 of the intermediate member 7, at two locations on the left and right of the rear, while the seat 6 has elongated holes 24 that are longitudinally oriented and open to the left and right, through which the guide shaft 25, which is inserted through the bearing piece 23, is inserted into the elongated holes 24 so as to be able to slide back and forth. The guide shaft 25 is held in place by screws 26 so as not to come out of the bearing piece 23.

[0035] A roller 27 is positioned at the front of the seat support 6 via a pair of upward-opening roller receiving recesses on the left and right. On the other hand, a metal receiving plate 28 that contacts the roller 27 is attached to the lower surface of the intermediate member 7. A longitudinal spring (compression coil spring) 29 is positioned at the front of the seat support 6 to provide resistance to the forward movement of the intermediate member 7. The spring 29 is positioned on both the left and right sides, with its front end supported by a front spring support provided on the seat support 6, and its rear end supported by a rear spring support (not shown) that protrudes downward from the intermediate member 7.

[0036] As shown in Figure 3, the lower end of the side support column 11 has an inward-facing portion 11a that fits from the outside into a lateral hole 30 formed in the seat receiver 6, and the inward-facing portion 11a is fixed to the seat receiver 6 by a screw 31.

[0037] (3) Mounting structure of the seat support Next, the mounting structure of the seat support 6 to the base 5 will be described mainly with reference to Figures 4 and 5.

[0038] As shown in Figure 4, the inward-facing portion 4a of the leg 4 penetrates the lower outer circumference of the base 5 and extends into the interior of the base 5, and this extended portion is welded to the base 5. The bottom plate of the base 5 has an upward-bulging annular projection 33, and the inward-facing portion 4a of the leg 4 is welded to overlap the inner circumference of the base 5 and the annular projection 33. The inward-facing portion 4a of the leg 4 is flattened into a square shape to increase the contact area with the base 5.

[0039] As clearly shown in Figure 5, a central shaft 34 projecting upward is welded to the center of the base 5. The central shaft 34 is straight, with an outward-facing flange 35 formed at its lower end and a small-diameter portion 36 formed at its upper end. Therefore, a shoulder portion 37 is formed at the upper end of the central shaft 34. A circular reinforcing plate 5b is welded to the lower surface of the base 5 (the reinforcing plate 5b may also be welded to the upper (bottom) surface of the base 5).

[0040] A sleeve 39 is rotatably fitted to the central shaft 34 from the outside via a bush 38, and the central hole 15 of the seat 6 is fitted into the sleeve 39. As previously described, the central hole 15 is a tapered hole that narrows towards the top, so the outer surface of the sleeve 39 is also tapered towards the top. On the other hand, the inner surface of the sleeve 39 is straight, and a bush 38 made of a plate material of equal thickness and friction is interposed between the sleeve 39 and the central shaft 34. The bush 38 is coated with a resin film with a low coefficient of friction on its inner surface (or outer surface or both surfaces). Therefore, the sleeve 39 can rotate while being tightly fitted to the central shaft 34.

[0041] As shown in Figure 4, the bush 38 is formed in a non-loop shape by the slit 40, and as the spacing of the slit 40 narrows, it tightly fits between the sleeve 39 and the central shaft 34. Therefore, fitting the bush 38 and sleeve 39 onto the central shaft 34 is done by force using a device such as a pressurizer.

[0042] The sleeve 39 rests on the lower end of the central shaft 34 via the lower flange 38a of the bush 38. Therefore, the load acting on the seat 2 is mainly supported by the flange 35 of the central shaft 34 via the sleeve 39.

[0043] An inward-facing flange 39a is formed at the upper end of the sleeve 39, with a slight gap between it and the upper end of the bush 38. A thrust bearing 41 is placed on top of the upper end of the sleeve 39, and the thrust bearing 41 is held in place from above by a bolt (screw) 44 via a disc washer 42 and a flat washer 43.

[0044] The thrust bearing 41 has a structure in which numerous balls are arranged between the upper and lower races, and the lower race is fitted onto the small diameter portion 36 of the central shaft 34 (it is also possible to fit the upper race onto the small diameter portion 36 of the central shaft 34). The disc washer 42 is an example of an elastic ring, and is positioned with its concave side facing downwards and is held in an elastically deformed state. In this way, the sleeve 39 is strongly pressed by the elastic restoring force of the disc washer 42, but because the thrust bearing 41 is interposed between the disc washer 42 and the sleeve 39, the sleeve 39 can rotate horizontally smoothly together with the seat 6.

[0045] In this embodiment, the sleeve 39, bush 38, thrust bearing 41, and disc washer 42 constitute the tilt-preventing member described in the claims, but in particular, the thrust bearing 41 and disc washer 42 form its core. Since the sleeve 39 is strongly pressed via the disc washer 42, it does not tilt relative to the axis of the central shaft 34 (relative to the vertical line) and rotates horizontally in a stable state without wobbling.

[0046] Now, the center of gravity of the downward load acting when a person sits on the seat is mostly offset from the axis of the central axis 34. As a result, a moment is generated in the seat 2 that tries to tilt it relative to the axis of the central axis 34. Therefore, if the upper or lower surface of the sleeve 39 lifts up due to the person sitting on it, the seat 2 becomes more prone to tipping over and looseness is likely to occur.

[0047] In contrast, in this embodiment, the sleeve 39 is tightly fitted onto the central shaft 34 via the bush 38, and the sleeve 39 is strongly pressed from above via the washer 42 and thrust bearing 41. As a result, the upper surface of the central shaft 34 is in close contact with the thrust bearing 41, and the lower surface is in close contact with the flange 35 of the central shaft 34. Therefore, the sleeve 39 does not tip over, and as a result, the seat 2 can be rotated horizontally in a stable position.

[0048] Furthermore, if the vertical height of the central shaft 34 and the central hole 15 can be increased to a certain extent, the seat 2 can be rotated without wobbling simply by fitting the sleeve 39 onto the central shaft 34. However, as in this embodiment, when the seat support 6 is positioned close to the base 5, the height (thickness) of the seat support 6 cannot be increased, so simply fitting the sleeve 39 onto the central shaft 34 will result in wobbling of the seat 2.

[0049] In contrast, in this embodiment, the sleeve 39 is strongly pressed downward via the thrust bearing 41 and the washer 42, which prevents the sleeve 39 from tipping over and allows the seat 2 to rotate in a stable position without wobbling.

[0050] As in the embodiment, forming an inward flange 39a on the sleeve 39 and stacking the thrust bearing 41 on it has the advantage of stably supporting the thrust bearing 41. In the embodiment, there is a gap between the flange 39a of the sleeve 39 and the shoulder portion 37 of the central shaft 34, so the lower end of the sleeve 39 can be firmly in contact with the flange 35, ensuring high stability. Furthermore, since the members constituting the tilt prevention member are completely hidden by the base 5, the aesthetics are not compromised.

[0051] It is also possible to directly press the flat washer 42 with the head of the bolt 44 without using a flat washer. Furthermore, it is possible to stack multiple flat washers 42 (in this case, it is preferable to have the convex surfaces facing each other, or the concave surfaces facing each other). The thrust bearing 41 can also be a metal type instead of a ball type. That is, the upper and lower... Lace (ring) It is also possible to use one where the two overlap with a lubricant in between. Alternatively, the upper and lower race A type that incorporates a slider with a low coefficient of friction between the elements can also be adopted.

[0052] Furthermore, since the upper part of the leg 4 extends diagonally downward from the outer surface of the base 5, there is a large gap between the leg 4 and the seat support 6. Therefore, even if a seated person places their fingertips on the upper part of the leg 4 and rotates the seat 2, their fingers will not get caught between the leg 4 and the seat support 6.

[0053] (4) Reference example Next, as shown in Figures 6 and 7 Reference example This will be explained. Reference example The outer circumference of the central shaft 34 and the inner circumference of the central hole 15 are formed in a straight line, and a bush 46 is tightly fitted between them to facilitate rotation. The bush 46 is fruit Similar to the mounting configuration, it is formed in a non-loop shape by a slit. The seat 6 is held in a non-removable position on the central shaft 34 by a flat washer 49 and a bolt 48. Grease is applied between the flat washer 49 and the seat 6, and an annular groove 50 is formed on the upper surface of the seat 6 to serve as a grease reservoir.

[0054] this Reference example As a fall prevention member, a large-diameter, ring-shaped rotational assist body 51 is used, which overlaps the flange 5a of the base 5 from above. The rotational assist body 51 is a type of thrust bearing and consists of an upper ring 52 and a lower ring 53 that overlap each other, with grease applied between them as a lubricant. The lower ring 53 has multiple annular grooves 54 that serve as grease reservoirs (one may also be used).

[0055] Furthermore, the lower ring 53 has a downward-facing cylindrical portion 55 that surrounds the flange 5a of the base 5 from the outside, and an upward-facing cylindrical portion 56 located on the outside of the upper ring 52. The downward-facing cylindrical portion 55 is centered concentrically with the central axis 34, while the annular recess 57 formed on the inside of the upward-facing cylindrical portion 56 serves as a grease receiver.

[0056] Furthermore, as shown in Figure 7, the upper ring 52 is provided with multiple inward-facing protrusions 58, which are fixed to the seat receiver 6 with screws 59, while the lower ring 53 has multiple positioning protrusions 60 formed on its lower surface, which fit into positioning holes 61 provided on the upper surface of the flange 5a of the base 5. Thus, the lower ring 53 is held concentric with the central axis 34 and unable to rotate horizontally.

[0057] The upper ring 52 is provided with one or more upward-facing protrusions 62, which are fitted into positioning holes 63 formed in the seat receiver 6.

[0058] this Reference example Therefore, because the diameter of the large-diameter, ring-shaped rotating assist body 51 is large, when a seated person rotates the seat, its center of gravity is located inside the rotating assist body 51, allowing the seat 2 to rotate horizontally in a stable position without wobbling.

[0059] Although embodiments of the present invention have been described above, the present invention can be implemented in various other ways. For example, the leg device is not limited to the rod-leg type, but can be implemented in various shapes and structures, such as a type having left and right frames formed in a U-shape or square shape when viewed from the side. Furthermore, the seat does not need to slide back and forth, and may be a type that only rotates horizontally. In addition, it is possible to fit the inner shell or outer shell constituting the seat onto the central axis. [Industrial applicability]

[0060] The present invention can be implemented in a chair. Therefore, it can be used industrially. [Explanation of symbols]

[0061] 1 leg device 2nd seat 4 stick feet 5 Base 5a Flange 6 seat support 7 Intermediate member 15 center hole 34 Center axis 35 Flange 36 Small diameter section 37 Shoulder 38,46 Bush 39 sleeves 41 Thrust bearings constituting the anti-tilting member 42. Pan washers (elastic rings) that constitute the anti-tipping member 44 Vol to

Claims

1. The leg device comprises a base fixedly attached to the leg assembly and a seat positioned on the base, wherein a central axis that serves as the horizontal rotation center of the seat is projected upward from the base, and a central hole is formed in the seat or the seat support that receives it, into which the central axis fits from above. A chair in which the seat or seat support is mounted to the base so as to be horizontally rotatable via a tipping prevention member that maintains the load acting on the seat so as to act exclusively in the vertical direction, The aforementioned central axis is straight and has the same outer diameter. The aforementioned anti-tilting member comprises a sleeve rotatably fitted tightly onto the central axis, a thrust bearing superimposed on the sleeve, and a bolt that holds and secures the thrust bearing. The outer diameter of the sleeve is formed on a tapered surface that narrows towards the top, The central hole of the seat or seat support is formed in a tapered shape that narrows towards the top so as to fit the sleeve non-rotatably. chair.

2. The sleeve is rotatably held via a bush that is in close contact with the central shaft, The thrust bearing is held in place by the bolt via an elastic ring that elastically deforms in the vertical direction. The chair described in claim 1.

3. The elastic ring is a spring washer. The chair described in claim 2.

Images