chair

Abstract

To provide a chair that firmly supports the spine, reduces the load on the spine, and allows a user to sit comfortably. [Solution] The chair comprises a seat portion 2 having a seat surface 1 on the upper surface for the user to sit on, and a backrest 3, the backrest having a pair of left and right bulging portions 13 that bulge out toward the front side, and a recess recessed toward the rear formed in the vertical direction between the left and right bulging portions.

Description

[Technical Field]

[0001] The present invention relates to a chair having a seat portion having a seat surface on the upper surface of which a user sits, and a backrest. [Background technology]

[0002] BACKGROUND ART Chairs that include a seat portion having a seat surface on the upper surface for a user to sit on, and a backrest are known (see, for example, Patent Document 1).

[0003] According to the chair described in the above document, the backrest has a lumbar support section that supports the user's lower back, thereby reducing the burden on the lower back. However, since the backrest is in close contact with the back of the seated user, some people may experience discomfort due to pressure on the protruding parts of the spine (mainly the spinous processes). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6416990 Summary of the Invention [Problem to be solved by the invention]

[0005] To provide a chair that includes a seat having a seat surface on the upper surface for a user to sit on, and a backrest, firmly supports the spine, reduces the load on the spine, and allows a user to sit comfortably. [Means for solving the problem]

[0006] In order to solve the above problems, the chair of the present invention comprises a seat portion having a seat surface on the upper surface for the user to sit on, and a backrest, wherein the backrest has a pair of left and right bulges that bulge out toward the front side, and a recess that is recessed toward the rear and extends in the vertical direction between the left and right bulges.

[0007] The recess may be formed in a wedge shape in a plan cross section.

[0008] The bulge may be a resiliently deformable cushion.

[0009] The front surface of each bulge may be formed in a shape that is inclined or curved forward outward in the left-right direction.

[0010] The seat portion may be formed by stacking a plurality of elastic layers in the vertical direction.

[0011] The seat may have a bottomed hole at a position where the user's buttocks will be placed when seated.

[0012] An armrest may be provided on one side or on both sides, and a grip portion may be formed protruding upward near the front end of the armrest, which can be gripped with the elbow resting on the top surface of the armrest.

[0013] The chair may include legs and a rocking mechanism for rocking the seat and the backrest back and forth relative to the legs. [Effects of the Invention]

[0014] The left and right bulges provide firm support for the back, reducing the strain on the back, and the spine fits into the recess formed between the left and right bulges, allowing for comfortable sitting. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a front view of a chair to which the present invention is applied. [Figure 2] FIG. 1 is a side view of a chair to which the present invention is applied. [Figure 3] FIG. 1 is a plan view of a chair to which the present invention is applied. [Figure 4] FIG. 10 is a side view showing the back-and-forth swinging action of the swinging mechanism. [Figure 5] FIG. 10 is a front view of a chair according to another embodiment of the present invention. [Figure 6] FIG. 10 is a side view of a chair according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0016] Fig. 1 is a front view of a chair to which the present invention is applied, Fig. 2 is a side view of the chair to which the present invention is applied, and Fig. 3 is a plan view of the chair to which the present invention is applied. The chair shown in the figures comprises a seat 2 having a seat surface 1 on the upper surface of which a user sits, a backrest 3, a frame 4 to which the seat 2 and backrest 3 are attached, legs 6, and a rocking mechanism 7 that rocks the seat 2 and backrest 3, which are integrated by the frame 4, back and forth relative to the legs 6 together with the frame 4.

[0017] The frame 4 has a seat-side frame 4a to which the seat 2 is attached, and a back-side frame 4b to which the backrest 3 is attached. The frame 4 is made of, for example, solid wood coated with polyurethane resin paint.

[0018] The seat-side frame 4a has a rectangular shape in plan view, while the backrest-side frame 4b is provided from the rear end of the seat-side frame 4a diagonally upward and rearward, and has an arc shape that curves forward and outward in the left-right direction in plan view.

[0019] The chair shown in the figure is also provided with a pair of armrests 8, 8 located on both the left and right sides. The armrest 8 is attached to the frame 4 by having its rear end portion attached to the left and right outer sides of the backrest-side frame 4b and its bottom end portion attached to the left and right outer sides of the seat-side frame 4a. In addition, a grip portion 9 protruding upward is formed near the front end of the armrest 8, which can be gripped with elbows resting on the upper surface of the armrest 8.

[0020] The upper part of the grip part 9 is a spherical shape that is flattened vertically, and the lower part has a circumferential depression, giving the entire grip part a rhomboid shape. By gripping the upper part of the grip part 9, a seated user can feel a sense of security and can also use it as an aid when standing up from a seated position.

[0021] In the illustrated example, a pair of armrests 8, 8 are provided on both the left and right sides, but an armrest 8 may be provided on only one side.

[0022] The seat 2 is an elastically deformable cushion, and is attached to the seat side frame 4a so that its upper surface forms the seat surface 1. The seat 2 is formed by stacking multiple elastic layers 11, 11 (see FIG. 5) in the vertical direction, each layer being made of an elastic material such as cotton, polyester, urethane, or gel.

[0023] A recess (bottomed hole) 12 is provided in the seat 2 at a location where the user's buttocks will be positioned when seated (in this example, the central and rearward portion in the left-right direction). The recess 12 has its bottom located inside the seat 2, penetrates the seat-side frame 4a, and opens downward. The depth of the recess 12 is set to about half the thickness of the seat 2 and the seat-side frame 4a.

[0024] The backrest 3 has a pair of left and right bulging portions 13, 13 that bulge out toward the front side. A recess 14 that is recessed rearward is formed in the vertical direction between the left and right bulging portions 13, 13. In this example, the recess 14 is formed from the upper end to the lower end of the backrest 3.

[0025] The bulging portions 13 are elastically deformable cushions, and the front surface of each of the bulging portions 13, 13 is formed in a shape that is inclined or curved forward outward in the left-right direction. Specifically, the majority of the front surface of each of the bulging portions 13, 13 (in this example, the portion that comes into contact with the back of the user when seated) is formed in an arc shape that is parallel or approximately parallel to the arc shape of the backrest side frame body 4b described above in a planar cross section.

[0026] The recess 14 is formed so that the inner portions in the left and right directions on the front surface of each of the bulging portions 13, 13 approach each other toward the rear, and thus has a wedge shape in a plan cross section.

[0027] The legs 6 have a pair of left and right front legs 16, 16 arranged below and towards the front of the seat side frame body 4a, a pair of left and right rear legs 17, 17 arranged towards the rear, a left-right crossbeam 18 installed between the midpoints of the left and right front legs 16, 16, an upper left-right support frame (support part) 19 installed between the midpoints of the left and right front legs 16, 16, a pair of left and right front and rear bases 21, 21, a lower support frame (support part) 22 suspended between the midpoints of the left and right bases 21, 21, a connecting frame 23 installed between the upper end of one of the left and right front legs 16 and the upper end of the rear leg 17 to connect and fix them together, and a connecting frame 24 installed between the upper end of the other of the left and right front legs 16 and the upper end of the rear leg 17 to connect and fix them together.

[0028] Each base 21 is formed horizontally in the front and rear directions so as to be stable on the ground, and the lower ends of the front leg 16 and rear leg 17 on the nearest side are attached to support them. The upper support frame 19 and the lower support frame 22 support the frame body 4 and the backrest 3 and seat 2 united therewith so that they can swing back and forth by means of a swing mechanism 7, which will be described later.

[0029] Next, the swing mechanism will be described with reference to FIGS.

[0030] 4 is a side view showing the forward / backward rocking action of the rocking mechanism. The rocking mechanism 7 shown in the figure has the above-mentioned upper support frame 19 and lower support frame 22, supports 27 (specifically, a pair of left and right hinges 27, 27) that support the frame 4 and the seat 2 and backrest 3 unitized thereby (hereinafter referred to as the "chair main body 26") on the upper support frame 19 so that they can rock up and down (swing forward and backward) around the front end of the frame 4, a biasing member 28 that is provided between the lower support frame 22 and the seat 2 and operates to expand and contract, and a restricting mechanism 29 (more specifically, a locking mechanism 29) that restricts the expansion and contracting action of the biasing member 28 to restrict (specifically, stop or prohibit) the rocking action of the chair main body 26.

[0031] Each support 27 has a plate-shaped mounting portion 27a attached and fixed to the bottom side of the frame body 4 (specifically, the seat side frame body 4a) with wood screws or the like, a plate-shaped mounting portion 27b attached and fixed to the rear side of the upper support frame with wood screws or the like, and a rotation shaft 27c that connects the two mounting portions 27a, 27b so that they can rotate relative to each other.

[0032] The left and right supports 27, 27 are positioned so that their rotation axes 27c are coaxial, and the chair body 26 is attached to and supported by the upper support frame 19 (legs 6) so that it can swing about the rotation axis 27c. With this support structure, the backrest 3 swings back and forth relative to the legs 6 about the rotation axis 27c, while the seat 2 swings up and down integrally with the backrest 3.

[0033] The biasing member 28 is a gas spring 28, which is configured to expand and contract as a whole, and is constantly biased in the expanding direction by the oil and gas filled inside. This gas spring 28 is disposed between the leg 6 and the chair body 26, with its upper end attached to the underside of the frame 4 (specifically, the seat-side frame 4a) so as to be rotatable back and forth, and its lower end attached to the upper side of the lower support frame 22 so as to be rotatable back and forth.

[0034] According to this structure, the gas spring 28 also functions as a support member 28 that supports the chair body 26 that is supported by the legs 6 so that it can swing.

[0035] This chair is equipped with a regulating mechanism 29 that regulates (prohibits) the rocking movement of the chair body relative to the legs 6 by regulating the relative forward and backward rotation of either the upper or lower end or both ends of the gas spring 28 with respect to the chair body 26 (legs 6), or by regulating the extension operation of the gas spring 28.

[0036] The illustrated regulating mechanism 29 has a switching operation device 31 and a linking mechanism (not shown) such as a wire that mechanically connects the switching operation device 31 to a switching member (not shown) on the gas spring 28 side.

[0037] This regulating mechanism 29 is configured so that by operating the switching member in one direction, it is switched to a regulating state (a locked state in which the gas spring 28 is locked at the extension length at that time) in which the expansion and contraction of the gas spring 28 is restricted, and by operating the switching member in the other direction, it is switched to a released state in which the restriction (lock) of the gas spring 28 is released and the gas spring 28 is allowed to extend.

[0038] The switching operation device 31 is a switching lever that can be swung left and right. Swinging the switching lever 31 to one side (left or right) results in a restricting operation in which the wire is pulled toward itself to switch the restriction mechanism 29 to the restricting state, and swinging the switching lever 31 to the other side results in a releasing operation in which the restriction mechanism 29 is switched to the released state. The switching lever 31 is constantly biased toward the restricting operation side by a biasing means (not shown) that biases the wire toward the gas spring to pull it toward the gas spring.

[0039] To briefly explain an example of the structure of the gas spring 28, the gas spring has a cylinder, a piston that slides axially within the cylinder, dividing the interior of the cylinder into a contraction chamber and an extension chamber, and a rod that is coaxial with the cylinder and protrudes in a straight line from the piston to one side (the extension side).

[0040] The rod is formed to a length that occupies the range from the inside to the outside of the cylinder. The extension chamber and the contraction chamber are connected by a communication hole (specifically, an orifice) that allows the passage of fluids such as oil or gas sealed in each chamber, and although both chambers are maintained at the same pressure, the surface on the opposite side (the contraction side) of the piston is larger than the extension side by the cross-sectional area of ​​the rod, so the rod is always biased in the extension side.

[0041] The switching member is a switching valve that opens and closes the orifice. When the switching valve closes the communication hole, the flow of fluid between the extension chamber and the contraction chamber is restricted, and the expansion / contraction action of the gas spring is restricted (prohibited). On the other hand, when the switching valve opens the communication hole, the flow of fluid between the extension chamber and the contraction chamber is permitted, allowing the gas spring to expand or contract.

[0042] It should be noted that the configurations of the gas spring 28 and the restriction mechanism 29 are merely examples, and various other configurations can be adopted.

[0043] When the regulating mechanism 29 is in the released state and the weight of the seated user moves backward, the gas spring 28 contracts due to the user's load, causing its upper end to rotate backward relative to the chair body 26 and its lower end to rotate forward relative to the legs 6, and the chair body 26 swings backward around the rotation axes 27c, 27c of the left and right supports 27, 27 as fulcrums, assuming a backward-inclined position as shown by the solid line in Figure 4.

[0044] On the other hand, when the regulating mechanism 29 is in the released state and the weight of the seated user moves forward, the load of the user on the gas spring 28 decreases, causing the gas spring 28 to extend, with its upper end rotating forward relative to the chair body 26 and its lower end rotating backward relative to the legs 6. At the same time, the chair body 26 swings forward around the rotation axes 27c, 27c of the left and right supports 27, 27 as fulcrums, causing the seat 2, shown by the virtual line in Figure 4, to assume an approximately horizontal position.

[0045] According to the rocking mechanism 7 configured as above, the chair body 26 rocks back and forth in response to the weight shift of the user, allowing the user to sit in a relaxed position.

[0046] 4, when the seat 2 is in a substantially horizontal position, the restriction mechanism 29 is released, and the user's weight shifts forward, the gas spring 28 expands, causing its upper end to rotate forward relative to the chair body 26 and its lower end to rotate backward relative to the legs 6. The chair body 26 then swings forward about the rotation axes 27c, 27c of the left and right supports 27, 27 as fulcrums, causing the seat 2 to tilt further forward from the substantially horizontal position. In this example, when the horizontal position of the seat 2 is taken as 0°, the chair body 26 swings forward to a forward tilt angle of approximately -3°, while the chair body swings backward to a backward tilt angle of approximately 9°.

[0047] Next, with reference to Figs. 5 and 6, a chair according to another embodiment of the present invention will be described with reference to the points that differ from the embodiment described above.

[0048] Fig. 5 is a front view of a chair according to another embodiment of the present invention, and Fig. 6 is a side view of a chair according to another embodiment of the present invention. The above-described embodiment is equipped with a rocking mechanism 7, and the legs 6 have a lateral crossbeam 18 extending between the midpoints of the left and right front legs 16, a lateral support 19 extending between the midpoints of the left and right front legs 16, a connecting frame 24 connecting the upper ends of the left and right front legs 16 and the rear legs 17, a grip 9 provided near the tip of the armrest 8, and a chair body 26 configured so that the seat 1 is in a substantially horizontal position in the initial state when the rocking mechanism 7 is not activated. However, the chair shown in the drawings does not have a rocking mechanism, the legs 6 do not have a crossbeam, a support, or a connecting frame, and no grip is provided, and the chair body 26 is tilted backward in the initial state. The front legs 16, 16 and the rear legs 17, 17 are arranged on the left and right outer sides of the seat and are integrally formed with the armrests 8, 8.

[0049] According to this configuration, the swing mechanism and the gripping portion are omitted and the structure of the leg portion is simplified, thereby reducing manufacturing costs.

[0050] The chair body 26 is covered with a removable cover. By replacing the cover, the appearance of the chair body 26 can be changed. The cover may be configured to cover the chair body 26 as a whole, or may be a separate cover that covers the seat 2 and the backrest 3 separately.

[0051] Furthermore, although the configuration shown in Figs. 5 and 6 does not have a grip portion, a grip portion may be provided near the tip of the armrest 8, as in the above-described example. [Explanation of symbols]

[0052] 1 seat 2 Seat part 3 Backrest 6 legs 7. Oscillating mechanism 8 armrests 9 Gripping part 11 Elastic layer 12 Recess (bottomed hole) 13 Bulge 14 Recess

Claims

1. a seat portion having a seat surface on the upper surface thereof for a user to sit on; It is equipped with a backrest, The backrest has a pair of left and right bulging portions bulging forward, Between the left and right bulges, a recessed area was formed in the vertical direction toward the rear. A chair characterized by:

2. The recess is formed in a wedge shape in a plan cross section. The chair of claim 1.

3. The bulge is an elastically deformable cushion. The chair of claim 1.

4. The front surface of each bulge is formed in a shape that is inclined or curved forward toward the outside in the left and right directions. The chair of claim 1.

5. The seat portion is formed by stacking a plurality of elastic layers in the vertical direction. The chair of claim 1.

6. A hole with a bottom is provided in the seat where the user's buttocks will be placed when sitting. The chair of claim 1.

7. An armrest is provided on one side or a pair of armrests is provided on both sides, A grip portion is formed protruding upward at a portion near the front end of the armrest, which can be gripped with an elbow resting on the upper surface of the armrest. The chair of claim 1.

8. The legs and a rocking mechanism for rocking the seat and the backrest back and forth relative to the legs. The chair of claim 1.

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