JP7191426B1 - Chair - Google Patents

Abstract

[PROBLEMS] To provide a chair that allows a user to unconsciously balance the center of gravity in the front, rear, left, and right directions by simply sitting on a seat, promotes a posture in which the pelvis is naturally erected, and maintains the posture. A chair having four legs, front, back, left, and right, and a seat surface, comprising a plurality of seat plates whose longitudinal direction is the user's front-back direction, and the seat surface is downwardly convex. A front support member that supports a plurality of seat plates with an ellipse and connects the front two legs out of the four legs, and an ellipse with a downwardly convex seat surface that supports the plurality of seat plates. a rear support member connecting the rear two legs of the legs of the book. The curve of the seat surface is a curve whose curvature increases from the longitudinal center of the front support member and the rear support member toward the left and right ends of the chair. [Selection diagram] Fig. 1

Description

The present invention relates to chairs. In particular, it relates to a chair for promoting maintenance of a correct posture with the pelvis upright.

In a general chair, a person is seated in a posture in which both feet are placed on the floor, the legs are bent almost at a right angle, the buttocks are placed on the seat surface of the chair, and the upper body is leaned against the backrest.

In such a chair, a person sitting on a chair leans his or her upper body against the backrest, or when eating or drinking toward a table, the upper body naturally bends toward the table, bending the spinal cord and correcting the posture itself. Deteriorate. In addition, sitting for a long time with the spinal cord flexed puts pressure on the internal organs, causing fatigue and stress.

For example, in Patent Document 1, in order to provide a chair in which the user can sit in a correct posture with the pelvis upright and the back straight, and which does not cause pain in the shins, there is a seating portion in contact with the buttocks, a shin guard portion in contact with the shins, and a seat. Disclosed is a chair composed of a chair body that supports a foot and a shin guard, and a footrest on which the soles of the feet are placed.

JP 2020-74874 A

In Patent Literature 1, the seat portion is inclined forward in order to allow the user to sit in a correct posture with the pelvis upright and the back straight. In addition, by tilting the seat forward, the load concentrated on the shin guard is distributed to the shin guard and the footrest in order to prevent the shin from being hurt by the shin guard.

However, the seat is still tilted forward, and a constant load is applied to the shin guards, making it difficult to completely eliminate the pain caused by the shin guards. Therefore, sitting for a long time puts a burden on the body.

Further, in Patent Document 1, although the center of gravity in the front and back of the user is taken into consideration, it is not taken into consideration that the user unconsciously balances the center of gravity in the front, back, left and right just by sitting on the seat. No.

To provide a chair in which a user unconsciously balances the center of gravity in the front, back, left and right directions by simply sitting on a seat, promotes a posture in which the pelvis is naturally erected, and maintains the posture. is.

One mode of a chair for solving the above-mentioned problems is a chair having at least four legs in front, back, left, and right, and a seat surface, wherein the seat surface comprises a plurality of seats whose longitudinal direction is the user's front-back direction. A seat plate, a front support member that supports the plurality of seat plates in a curved line with the seat surface protruding downward, and connects the front two legs out of the four legs, and the plurality of seat plates as described above. a rear support member that supports the seat surface with a downwardly convex curve and connects the rear two legs out of the four legs,
The seat surface is
It is a downwardly convex curve that is symmetrical with respect to the center of the longitudinal direction of the front support member and the rear support member, and the front support member and the rear support member on the adjacent seat plates of the plurality of seat plates. The curvature of the upper shape of is a curve that increases from the center of the longitudinal direction of the front support member and the rear support member toward the left and right ends of the chair.

According to the present invention, by sitting on a chair, the user can be guided to a "posture with the pelvis upright (correct posture)" and can continue to maintain that posture.

It is the perspective view which looked at the chair of a present Example from upper direction. It is a figure which shows a mode that it sat down on the chair by the correct posture. It is a figure explaining the dimension of the main parts of a pelvis. It is a figure explaining the dimension of the seat surface of the chair of a present Example. It is the figure which showed the ellipse of the seat surface part by the difference of the physique. It is a figure showing the seat surface of the chair of a present Example. It is a figure which shows the seat surface of the chair of a present Example, Comprising: The seat surface comprised with two types of seat plates. FIG. 10 is a diagram showing an example of the seat surface of the chair of the present embodiment, in which the number of seat plates having the same width is an odd number. It is a figure explaining the reaction force of the seat surface of the chair of a present Example. It is a figure explaining the reaction force direction of the seat surface of the chair of a present Example. It is the top view (a) of the chair of a present Example, a side view (b), and a front view (c).

When the chair of this embodiment is seated, it naturally encourages a posture in which the pelvis is erected, and maintains that posture.

"Posture with the pelvis upright" means "the pelvis is in the correct position." In other words, by raising the pelvis, you can create the correct posture. Even if you are sitting on a chair, you can sit with your pelvis in the correct position by raising your pelvis.

The "posture with the pelvis upright" means the following states (a) and (b).

(a) The pelvis is horizontally horizontal. Normally, when sitting on a chair, it is necessary to consciously create a posture in which the positions of the knees are symmetrical.

(b) The pelvis is upright. FIG. 2 shows a state in which the pelvis is standing while sitting on a chair. As shown in FIG. 2, when the pelvis is viewed from the side, it is neither tilted forward nor tilted backward, just standing straight. When the lumbar spine and pubic line are straight, the pelvis is in the correct upright position.

Continuing to sit while the pelvis is not standing puts a burden on the pelvis, which leads to a chain reaction that causes headaches, stiff shoulders, and fatigue. In addition, there is a danger that the pelvis will be distorted.

If you do not keep your pelvis upright when sitting on a chair, your pelvis will tilt backwards, making it difficult to support your heavy upper body. Therefore, by rounding the spine, the head is forward and balanced. These conditions create incorrect “bad posture”. If it becomes a habit to work in a bad posture, it will lead to distortion of the pelvis and spine, and if the distortion of the pelvis and spine becomes serious, it will be difficult to correct it.

In particular, the pelvis supports the internal organs for those with a body type that easily gains weight. In other words, it is in a state where the internal organs are on top of the pelvis. If you continue to sit in a posture that puts a strain on your body without sitting with your pelvis upright, your pelvis will become distorted as mentioned above. If the pelvis is distorted, the viscera on top of the pelvis will drop down, and the viscera will gather in the pelvis. As a result, metabolism and blood flow deteriorate, causing a “body type that is easy to gain weight” and “lower body fatness”. On the other hand, you can expect a diet effect by sitting with the correct pelvis. In addition, breathing becomes easier and stress can be eliminated.

In order to sit with your pelvis upright, you should sit deeply in the chair, and when you sit in the chair with your back straight, be aware that your sit bones are firmly in contact with the seat surface of the chair. It is necessary to be conscious of keeping it horizontal.

In other words, it is necessary for the person (user) who sits on the chair to be aware of the "posture with the pelvis upright," that is, the correct posture. It is possible to be aware of the correct posture for a while after sitting down, but it is actually difficult to continue to be aware of the correct posture when sitting for a long time or working at a desk.

By sitting on the chair of the present embodiment, the user can be guided to the "posture with the pelvis upright (correct posture)" without being conscious of it, and can continue to maintain that posture.

In addition, the chair of this embodiment maintains a correct posture, thereby balancing the user's postural muscles and strengthening the user's trunk.

In addition, the chair of the present embodiment trains the user's postural muscles and trunk, thereby training the user's ability to walk.

Preferred embodiments of the present invention will now be described with reference to the drawings. In the drawings below, for the sake of simplification of the description, the same reference numerals are given to members and portions having the same function, and redundant description may be omitted or simplified. Also, the dimensional relationships (length, width, thickness, etc.) in each drawing may not necessarily accurately reflect the actual dimensional relationships. Matters other than those specifically mentioned in this specification, which are necessary for carrying out the present invention, can be grasped as design matters by those skilled in the art based on the prior art in the relevant field. The present invention can be implemented based on the contents disclosed by the specification and drawings and the common general technical knowledge in the field. Additionally, the invention is not limited to the following examples.

Hereinafter, embodiments will be described in detail with reference to the drawings.

FIG. 1 is a perspective view of the chair of Example 1 as seen obliquely from above.

The chair 1 of this embodiment has four legs: legs 10, 11, 12 and 13 (not shown). The left leg 10 and leg 11 seen from the front are connected and supported by a left lower support member 14 and an upper support member 18 that also serves as an armrest. A member composed of the leg 10, the leg 11, the lower support member 14, and the upper support member 18 is called a left A-shaped frame. As is well known, the shape of the A-shaped frame is such that the two legs are symmetrical when viewed from the side of the chair.

They are connected and supported by a right leg 12, a leg 13, a right lower support member 15 supporting the legs 12 and 13, and an upper support member 20 which also serves as an armrest. A member composed of the leg 12, the leg 13, the lower support member 15, and the upper support member 20 is called a right A-shaped frame.

The left A-shaped frame and the right A-shaped frame are connected and supported by a front support member 16 and a rear support member 17 .

The left A-shaped frame is configured symmetrically when viewed from the lateral direction of the chair, and the interval between the legs 10 and 11 is widened downward and narrowed upward. That is, the legs 10 and 11 are evenly inclined forward and backward on the front left side. The position of the intersection point A (not shown) between the longitudinal center line of the leg 10 and the longitudinal center line of the leg 11 corresponds to the height of the user's head when the user is seated on the chair 1. do.

The right A-shaped frame is similar to the left A-shaped frame, and the chair 1 is bilaterally symmetrical when viewed from the lateral direction of the chair. The interval between the legs 12 and 13 is wider downward and narrower upward. That is, the legs 12 and 13 are evenly inclined forward and backward on the front right side. The position of the intersection point B (not shown) between the longitudinal center line of the leg 12 and the longitudinal center line of the leg 13 corresponds to the height of the user's head when the user is seated on the chair 1. do.

The height of the intersection point A and the intersection point B is the height of the head when the user is seated, so that the front-rear balance of the chair 1 can be configured with the minimum necessary materials (leg length). . That is, increasing the inclination of the legs 10 and 11 increases the length of the legs and increases the weight of the chair. On the other hand, when the inclination of the legs 10 and 11 is small, it is difficult to maintain the front-rear balance of the chair 1, and the chair tends to tip over. In addition, the proper inclination of the legs 10 and 11 encourages the user to maintain balance in the front-rear and left-right directions.

The front support member 16 and the rear support member 17 connect and support the left A-shaped frame and the right A-shaped frame, and also play a role of supporting a plurality of seat plates 19 that constitute the seat surface. The seat plate 19 is a straight plate having a predetermined width in the longitudinal direction. The curved line is symmetrical with respect to the center of the member 17 in the longitudinal direction and is convex downward. Details of this curve will be described later.

The front support member 16 supports the plurality of seat plates 19 in the vicinity of one end of the front (front) of the plurality of seat plates 19 so that the seat surface forms a bilaterally symmetrical curved surface that protrudes downward, and has four legs. are connected to the front two legs (leg 10, leg 12), respectively.

The rear support member 17 supports the plurality of seat plates 19 near the other rear end of the plurality of seat plates 19 so that the seat surfaces form a bilaterally symmetrical curved surface that protrudes downward, and the rear of the four legs. are connected to the two legs (leg 11, leg 13) of each. The shapes of the upper surfaces of the front support member 16 and the rear support member 17 and the seat plate 19 will be described in detail with reference to FIGS. 3 to 8. FIG. In this embodiment, four legs are used, but the number of legs is not limited to four. In this case, the front support member 16 and the rear support member 17 function as a structure for supporting the seat plate 19 forming the seat surface on the curved surface.

Before explaining the shapes of the upper surfaces of the front support member 16 and the rear support member 17, that is, the shapes of the front support member 16 and the rear support member 17 on which the seat plate 19 is installed, the dimensions of major parts of the human pelvis will be explained. do. As shown in FIG. 3, let Dx be the distance between the left and right ends of the left and right ilium, Dy be the distance from the upper end of the ilium to the lower end of the ischial bone, and Dz be the distance between the lower ends of the left and right ischial bones.

Hereinafter, the upper shapes of the front support member 16 and the rear support member 17 are symmetrical curves with respect to the center of the longitudinal direction of the front support member 16 and the rear support member 17 (lateral direction of the chair 1). The curvatures of the upper shapes of the front support member 16 and the rear support member 17 at the left and right adjacent seat plates (for example, the center of the seat plate) are different curves, and the upper portions of the front support member 16 and the rear support member 17 have different curvatures. The curvature of increases from the lateral center of the chair 1 toward the left and right ends of the chair 1 . More specifically, the radius of curvature r becomes a value close to infinity at the center of the chair 1 in the lateral direction, and at both ends of the seat surface, it has a value of W/5 or less of the seat width W, that is, 20% of the seat width W. Below. An elliptical example will be described below assuming that this curve is a symmetrical downward convex curve, but the upper shape of the front support member 16 and the rear support member 17 is not limited to an ellipse.

The ellipses of the upper surfaces of the front support member 16 and the rear support member 17 are symmetrical ellipses centered on the center line of the front support member 16 and the rear support member 17 . The front support member 16 and the rear support member 17 basically have the same shape, and the elliptical shape of the upper surface thereof has an optimum value determined by the above Dx, Dy, and Dz. Incidentally, in determining the elliptical shape, the width W of the seating surface composed of the plurality of seating surface plates 19 may be taken into consideration.

FIG. 4 is a diagram for explaining the dimensions of the seat surface of the chair of this embodiment. The upper surfaces of the front support member 16 and the rear support member 17 are ellipses represented by Equation 1 in FIG. Here, the ellipse is 2a in the x direction (length of the major axis) and 2b in the y direction (length of the minor axis). A distance 2c between the two focal points F1 and F2 of the ellipse is represented by Equation 2 in FIG.

In this embodiment, the relationship between the distance 2c between the focal points F1 and F2 and the width W of the seat surface of the chair 1 is represented by Equation 3 in FIG. In other words, the distance 2c between the focal points F1 and F2 is equal to the width W of the seat surface, or 1.15 times W or less.

The curvature greatly changes between the central side and the outer side of the focal points F1 and F2. If the focal length is too short, for example, if the focal point is inside the edge of the seat, the user will feel cramped when sitting. In addition, the thighs are subjected to an inward rotation force, making it impossible to disperse body pressure appropriately, making it impossible to maintain the front-rear balance of the user's sitting posture. As a result, the posture becomes collapsed, and the user feels pressured and easily gets tired.

On the other hand, if the focal length is too long, the seat surface becomes almost flat, and body pressure tends to be concentrated near the ischial tuberosities, making it easier to feel the gap between the bottom and the bottom. This is because the shape of the surface cannot be expected to maintain the left-right balance of the user of the chair.

Since the seat width of a general chair is 40 to 45 cm in consideration of the general body shape of the user, the seat width of the chair is assumed to be 45 cm in this embodiment. If the seat width is 45 cm, the distance between the focal points F1 and F2 is also 45 cm. However, the width of the seat surface is not limited to 45 cm, but can be appropriately determined according to the body shape of the user. In this embodiment, the distance between the focal points F1 and F2 is the width W of the seat surface of the chair 1. .15 W), the effect of guiding the pelvis to a standing posture is obtained.

In describing the distance Dx between the left and right ends of the left and right ilium, the distance Dy from the upper end of the ilium to the lower end of the ischial bone, and the distance Dz between the lower ends of the left and right ischial bones, Dx is 28 cm, Dy is 21 cm, and Dz is 7 cm.

Let the length in the y direction from the lowest point of the ellipse to the focal point F1, F2 be the distance Dy from the upper end of the ilium to the lower end of the ischium. That is, b, which is half the length of the short axis, is determined according to the distance Dy from the upper end of the ilium of the user of the chair 1 to the lower end of the ischium.

The inventors have repeatedly conducted various studies and found that the lateral shape of the seat surface viewed from the front of the chair is
(2) The distance between the focal points F1 and F2 of the ellipse is the seat width W (the distance between the focal points F1 and F2 is the seat surface width Dy). It is a part of a bilaterally symmetrical ellipse that is approximately equal to the width W (W≤2c≤1.15W).

As a result, it was found that the body pressure was easily distributed around the ischial tuberosity. Assuming that the lateral shape of the seat surface seen from the front of the chair is as described above, the human skeleton is bilaterally symmetrical, so the user's own weight naturally balances the front, back, left, and right of the pelvis, postural muscles, etc. can. In addition, in order to effectively balance the left and right of the user's postural muscles, the seat surface should be part of a symmetrical ellipse, and the front-rear direction of the seat surface when viewed from the front of the chair should be a straight line. was found to be most effective.

In other words, by making the front and back shape of the seat surface as seen from the front of the chair a straight line, unnecessary reaction force does not occur in the front and back direction, so the effect of making it a part of the symmetrical ellipse is maximized and can be used. It is possible to guide the person to the "posture with the pelvis upright (correct posture)" and to maintain that posture.

Based on the above premises, when the major axis and the minor axis are obtained, the distance between the major axis 2a is 58.56 to 62.36 cm, and a is about 30 cm.

The upper surface of the front support member 16 is made up of an ellipse with a of 30 cm, b of 21 cm, and a distance between the focal points of 45 cm. The upper surface of the rear support member 17 has the same shape as that of the front support member 16, and is similarly elliptical. To be precise, the thickness of the seat plates 19 must be considered, and the upper surfaces of the seat plates 19 mounted on the front support member 16 and the rear support member 17 are 30 cm in a and 21 cm in b. , constitute an ellipse with a focal distance of 45 cm.

The optimum value of the above dimension varies depending on the distance Dy from the upper end of the user's ilium to the lower end of the ischial bone. That is, when Dy is 17 cm, a is 28.2 cm. Also, when Dy is 25 cm, a is 33.6 cm.

FIG. 5 is a diagram showing the ellipse of the seat surface portion due to the difference in physique. An ellipse 51 is shown when Dy is 17 cm (physique), an ellipse 52 is shown when Dy is 21 cm, and an ellipse 53 is shown when Dy is 25 cm. It should be noted that the ellipse 51, 53 is not adapted to the condition that the bearing surface width W is the distance 2a between the focal points. As shown in FIG. 5, the shapes of the upper surfaces of the front support member 16 and the rear support member 17 are substantially the same regardless of the difference in Dy, that is, the difference in the physique of the chair user. Therefore, the upper surfaces of the front support member 16 and the rear support member 17 should be elliptical with a basic body shape Dy (=b) of 21 cm and a seat width W equal to the distance between two focal points (2a). Therefore, it is possible to configure a general-purpose chair that can accommodate users of any system to some extent.

In addition, on the premise that the standard figure Dy is 21 cm and the seat width W is 45 cm, the length 2b of the minor axis of the ellipse, the seat width W, and the seat height H are approximately the same. If the value is (±5 cm), the effect of guiding the user to "posture with the pelvis upright (correct posture)" and maintaining that posture can be expected regardless of the user's body shape.

However, if the user of the chair is a child, the seat width W' is 36 cm and Dy (=b) is approximately 18 to 21 cm. Appropriate values are obtained from Equations 2 and 3.

Also, if the user of the chair is an infant, the seat width W'' is 26.5 cm and Dy (=b) is about 15 cm, so it is necessary to configure the seat surface with a different ellipse. Appropriate values are obtained from the equations 2 and 3 of 4.

The curvature radius r1 of the right and left ends of the seat surface is ⅕ or less of the seat width W, regardless of whether the user of the chair is an adult, a child, or an infant. Formula 4 in FIG. 4 is a formula for obtaining the radius of curvature r of the ellipse.

Substituting the aforementioned constraint conditions, that is, 2c=W, b=Dy, and the x-coordinate of the focal point (determined from the relationship of Equation 2 in FIG. 3) into Equation 4, the radius of curvature r1 of the bearing surface end is: , 61.5 mm.

If the bearing surface width W is used to approximate the curvature radius r1 of the bearing surface end, it is W/7.

Substituting various values of Dy and seat width W as dimensions of a general chair and approximating the radius of curvature r1 at the end of the seat with the seat width W, the range of W/10<r1<W/5 is.

As described above, the curved line formed by the front support member 16 and the rear support member 17 that support the plurality of seat plates 19 is a curved line in which the seat surface is convex downward. It is a downwardly convex curve that is symmetrical with respect to the center in the longitudinal direction. More preferably, the curve formed by the front support member 16 and the rear support member 17 is such that the curvature of the upper shape of the front support member 16 and the rear support member 17 on adjacent seat plates of the plurality of seat plates 19 is equal to the front support member. The curve increases from the longitudinal center of the member 16 and the rear support member 17 toward the left and right ends of the chair. A suitable shape for that purpose is to configure the curve formed by the front support member 16 and the rear support member 17 as an ellipse, and increase the radius of curvature r of the ellipse of the seat surface from a value close to infinity at the center to the end of the seat surface. gradually decrease. The range of the radius of curvature r is W/10<r<infinity.

It is said that raising the pelvis is effective in clarifying the mind, establishing independence, and improving health. In other words, as the mind becomes clearer, the head becomes clearer, one can concentrate on anything, the ability to make judgments, the acquisition of practical wisdom, the mind tightens, and one's motivation rises. As independence is established, the ability to concentrate, to be able to sustain, to work willingly, to be proactive, to be tenacious and to endure, and to acquire practical ability. To be healthy, correct posture eliminates pressure on the internal organs, eliminates anorexia, and makes movements more agile.

According to the chair of the present embodiment, the user is naturally guided to a posture in which the pelvis is erected without being conscious of it just by sitting down.

It should be noted that the shape of the seat formed by the plurality of seat plates 19 is one of the important factors for allowing the pelvis to stand up when the user sits on the chair. Therefore, the front support member 16 and the rear support member 17 can adopt various modifications as long as the seat surface can be configured by supporting a plurality of seat plates 19 in a downward convex shape. For example, the seat surface composed of a plurality of seat plates 19 is a curved line that is symmetrical with respect to the center in the horizontal direction of the chair 1 and convex downward. It is a curve that becomes larger as it approaches the left and right ends of the chair 1 from the center of the direction. Preferably, the radius of curvature r0 of the center in the horizontal direction of the chair 1 is close to infinity, and the radius of curvature r1 of the right and left ends of the seat surface is less than or equal to W/5 of the seat width. An ellipse is the most efficient shape for creating this seating surface.

In Example 2, as in Example 1, the seat surface composed of the plurality of seat plates 19 is a curved line that is symmetrical with respect to the center of the chair 1 in the horizontal direction and convex downward. The curvature of the seat plate is a curve that increases from the lateral center of the chair 1 toward the left and right ends of the chair 1 . Preferably, the radius of curvature r0 of the center in the horizontal direction of the chair 1 is close to infinity, and the radius of curvature r1 of the right and left ends of the seat surface is less than or equal to W/5 of the seat width. Since such a seat surface is composed of a plurality of seat surface plates 19, the shapes of the upper surfaces of the front support member 16 and the rear support member 17 are configured as described in the first embodiment.

6A is a top view of the seat surface of the chair of Example 2. FIG. In FIG. 1, seat plates 19 with the same width are used, but in FIG. 6A, six seat plates 19 with three different widths are used to form the seat surface. The seat plate 19a and the seat plate 19f placed near the seat end have the same width w1 (horizontal direction), and the seat plate 19b and the seat plate 19e have the same width w2 (horizontal direction). , the seat plate 19c and the seat plate 19d near the center line 61 of the seat have the same width w3 (horizontal direction). The width of the seat plate 19 has a relationship of w1≦w2<w3. This is because when the user sits on the chair 1, a greater load is applied near the center line 61, so that the strength of the seat plate 19 is ensured and the difference in the distance Dz between the lower ends of the user's sit bones is absorbed. is. That is, among the plurality of seat plates 19, the widths of the two seat plates 19c and 19d near the center line 61 of the seat surface are determined by the position of the user's sitting bones.

On the other hand, near the edge of the seat, a large load is not applied, but the width of the seat plate is reduced in order to make it easier to feel the reaction force (pressure) acting on the user when the user's posture collapses to the left or right. there is

Also, the centers 54 and 55 of the respective center lines 62 and 63 of the seat plate 19c and the seat plate 19d near the center line 61 of the seat surface should coincide with the position of the ischium when the user sits on the chair 1. is preferred. Assuming that the width of the sit bone is 7 cm, the distance between center points 54 and 55 is 7 cm.

Each seat plate 19 has a length of 350 mm and widths w1, w2, and w3. do. Therefore, the cross-section of the seat surface in the front-rear direction is a straight line, and does not have a curved shape with the buttocks recessed like a common chair. This is because the pelvis is evenly distributed on the left and right sides, and in order to make the pelvis stand upright, it is necessary to maintain the left-right equal reaction force (which will be described later as the reaction force of the normal vector to the tangent line of the ellipse) and balance the left and right sides. It is based on the knowledge that it is effective. In other words, it is based on the knowledge that if the buttocks are recessed forward and backward, the effect of balancing the right and left sides is rather hindered. Therefore, the seat surface plate 19 is used, and the cross section of the seat surface in the front-rear direction is a straight line.

Although FIG. 6A shows an example in which the seat plate 19 is composed of three types of seat plates, the number of seat plates in the figure may be an even number. Also, regardless of the number of the seat plates 19, the width of the seat plate is made smaller toward the right and left ends of the seat surface. Alternatively, the width of the two seat plates at both ends of the seat surface may be made smaller than the width of the other seat plates.

Further, as another example of configuring the seat surface, the seat surface can be configured with two types of seat plates as shown in FIG. 6B. In order to absorb the difference in the distance Dz between the lower ends of the sitting bones of the user, the width w4 of the two central seat plates is larger than the width w5 of the other seat plates. By using a wide seat plate in the center of the seat surface, it is possible to efficiently absorb the difference in the position of the user's ischium, to reliably support the user's ischium with one seat plate, and to have a width of w5. is the width of the standard cedar board, the standard cedar board can be used for many seat boards that make up the seat.

In the example of FIG. 6B, the seat surface is composed of eight seat plates, but the number of seat plates is not limited to this. A plurality of seat plates having the same width can be used if the pressure felt by the user from the seat plates at the left and right ends is not considered.

FIG. 6C shows an example in which the number of seat plates having the same width w6 is an odd number.

The width of the seat plate 19 is the width of a standard Japanese cedar board of 45 mm. Ability to absorb differences in lower end of person's ischium. It is preferable that the center line of each of the seat plates 19b and 19c in the left-right direction coincide with the position of the ischium when the user sits on the chair 1. As shown in FIG. By adopting such a configuration, it is possible to absorb the difference in the position of the user's ischium, and to reliably support the user's ischium with a single seat plate. Moreover, since the width of the standard cedar board can be used to configure the seat surface, the processing cost can be reduced and the manufacturing efficiency can be improved.

FIG. 7 is a diagram illustrating an example of the reaction force of the seat surfaces of the chairs of Examples 1 and 2. FIG.

A load 71 acts on the seat plate 19 that constitutes the seat surface. The load 71 is represented by a normal vector 72 and a horizontal vector 73 when the load 71 is represented by a vector in the normal direction and the horizontal direction of the seat plate 19. be able to. The normal direction is the normal to the tangent to the ellipse of the upper surface of the front support member 16 or the rear support member 17, and the reaction force of the normal vector 72 is evenly distributed to the left and right toward the center line of the seat surface of the chair 1. works.

FIG. 8 is a diagram for explaining the reaction force direction of the seat surface of the chair of this embodiment.

On the minor axis of the ellipse, that is, at the point of contact S between the ellipse and its tangent, the reaction force of the normal vector acts along the y-axis. At the point of contact T between the ellipse and the tangent, which is slightly outside the point of contact S, the reaction force of the normal vector intersects with the point of intersection P on the y-axis. At the point of contact U between the ellipse and the tangent, which is farther outward from the point of contact T, the reaction force of the normal vector intersects with the point of intersection Q on the y-axis. Further outside from the point of contact U, on the long axis, the reaction force of the normal vector is directed to the x-axis, ie, the center O of the ellipse.

In this way, the point of intersection between the reaction force of the normal vector and the y-axis approaches the center O of the ellipse from infinity on the y-axis toward the outside of the ellipse. This is because when the user sits on the chair 1 with a correct posture, the user receives a reaction force along the y-axis and is less likely to get tired. Therefore, the user unconsciously maintains this comfortable posture, so that the posture muscles are well-balanced. When the user's posture is tilted to the left or right, a reaction force of the normal vector is generated according to the tilt, and the user is naturally guided to a state in which the left and right are balanced.

In addition, since the user's buttocks are evenly supported so as to be pinched from the left and right, the user is guided to the "posture with the pelvis upright (correct posture)" without being conscious of it by sitting on the chair. You can keep your posture.

Also, by maintaining a correct posture, the trunk of the user can be strengthened.

Also, by training the trunk of the user, it is possible to train walking power. That is, it is possible to train a group of abdominal muscles called postural muscles, iliopsoas muscles, quadriceps femoris muscles, renal muscles, and erector spinae muscles in a well-balanced manner. In addition, by maintaining the correct posture, you can train your postural muscles, hamstrings, and trapezius muscles in a well-balanced manner. You can maintain a well-balanced body that is less likely to get tired.

The height of the intersection point Q between the reaction force of the normal vector at the end of the seat surface and the y-axis is near the center of gravity of the user's upper body when seated on the chair.

Solid cedar wood is used for all materials constituting the chair 1 . By using cedar, it is possible to obtain the characteristics of cedar, such as moisture retention, heat retention, and antibacterial action. In addition to maintaining correct posture, the scent of cedar helps to recover from fatigue and relieve stress, and the earthing effect prevents poor health caused by static electricity. In particular, if the seat plate 19 is made of cedar wood, the moderate friction of the cedar wood contributes to the maintenance of the correct posture of the user for a long period of time.

In the above embodiment, Dx, Dy, Dz, and W represent the optimum values of the ellipses of the upper surfaces of the front support member 16 and the rear support member 17 of the chair. The ellipse on the upper surface of is not limited to an optimum value, and is symmetrical from the center of the seat surface and convex downward (a curved line that is symmetrical and convex downward with respect to the center of the horizontal direction of the chair 1) , the curvature of the adjacent seat plates increases from the center in the horizontal direction of the chair 1 toward the left and right ends of the chair 1). .

As described above, according to the chair of this embodiment, the user can sit on the chair by evenly supporting the user's buttocks from the left and right with the curved surface of the seat that is convex downward. , without being conscious of it, you can be guided to the "posture with the pelvis upright (correct posture)" and continue to maintain that posture.

In addition, the right and left ischial bones of the user can be reliably supported by a single seat plate.

FIG. 9 illustrates the plan view (a), side view (b), and front view (c) of the chair 1 of Example 1 using specific numerical values.

In this embodiment, the upper surfaces of the front support member 16 and the rear support member 17 are supported in a downwardly convex curve. As described in the first embodiment, this downwardly convex curve shows that the curvature of the upper shape of the front support member 16 and the rear support member 17 changes from the lateral center of the chair 1 toward the left and right ends of the chair 1. Therefore, it is a curve that grows, and an ellipse is also included.

The width of the seat surface is 45 cm, the height of the seat surface is also 45 cm, and the radius of curvature r1 of the left and right ends of the seat surface is the same value. Although it is necessary to adjust the dimensions according to the size of the user's body, by setting the height of the seat, the width of the seat, and the radius of curvature r1 of the left and right ends of the seat to W/2 or less, When the user sits on the chair, the user's upper body is balanced in the front, back, left, and right directions so that the user feels most comfortable.

As shown in FIG. 9(b), a left A-shaped frame is composed of a leg 10, a leg 11, a left lower support member 14, and a left upper support member 18. As shown in FIG. Similarly, the right A-shaped frame is composed of the leg 12, the leg 13, the right lower support member 15, and the right upper support member 20. As shown in FIG.

As shown in FIGS. 9(a) and 9(c), the nine seat plates 19 are supported on the upper surfaces of the front support member 16 and the rear support member 17 in downward convex curves. As the center of the front support member 16 and the rear support member 17 approaches the left A-shaped frame 96 and the right A-shaped frame 97, the inclination increases. As the right A-shaped frame and the left A-shaped frame are approached, the reaction force of the user's weight moves toward the center of the curve (ellipse) of the upper surface of the front support member 16 and the rear support member 17, that is, when the user is seated. Aimed at the center of gravity of the upper body.

In this embodiment, the height of the seat surface, the width of the seat surface, the diameter of the arc of the seat surface, and the like are changed to the same values according to the body shape of the user.

By evenly supporting the user's buttocks from the left and right sides of the seat surface with a downward convex curve, the user is guided to the correct posture without being conscious of it by sitting on the chair. You can keep holding that position. Convex curves include ellipses, parabolas, and circles.

Dowels 95 are provided to secure leg 10, leg 11, left lower support member 14, and left upper support member 18 to the left A-frame. The same applies to the right A-type frame.

In FIG. 9A, the thickness (horizontal direction) of legs 10, 11, 12, and 13 is about 30 mm, and the left A-shaped frame and the right A-shaped frame are separated by 450 mm.

Please refer to the side view of FIG.9(b). The left and right A-frames have upper ends with a length of about 315 mm, and the lower support member 12 is installed at a height 26 of about 250 mm from the ground to connect the legs 10 and 11 . The width of the leg 10, leg 11 and lower support member 12 is 45 mm.

A method of fixing the front support member 16 and the rear support member 17 to the legs 10, 11, 12 and 13 will be described with reference to FIG. 9(b). Since the fixing method is basically common to all legs, the fixing of the front support member 16 to the leg 10 will be described. The front support member 16 is secured to the leg 10 by two dowels 95d, 95e. Since the two dowels 95d and 95e are provided side by side in the vertical direction, the load received by the seat surface is transmitted vertically to the leg 10, so the load from the two dowels is evenly distributed and transmitted to the leg 10. . The rear supporting member 17 is fixed to the leg 11 by two vertically aligned joints, and the legs 12 and 13 are fixed to the front supporting member 16 and the rear supporting member 17 by two dowels, respectively. .

Also, as shown in FIG. 9(b), the legs 10 and 11 of the left A-type frame are bilaterally symmetrical (anteroposteriorly symmetric in FIG. 9(a)). The distance is narrower. The position of the intersection of the extended center lines of the legs 10 and 11 is the height of the user's head when the user is seated on the chair 1 .

The height H of the seat surface, the width W of the seat surface, and the curvature radius r1 of the left and right ends of the seat surface shown in the third embodiment are set to the width of the seat surface W/5 (including ±10%). , the fixing of the front support member and the rear support member that support the legs and the seat surface with dowels, and the intersection point where the center lines of the two legs in the longitudinal direction are extended on the left and right sides of the chair 1 can be applied to the first embodiment. can.

As described above, according to the chair of each embodiment, the trunk of the user can be adjusted by maintaining the correct posture.

Also, by training the trunk of the user, it is possible to train walking power. That is, it is possible to balance the abdominal muscle group called postural muscles, the iliopsoas muscle, the quadriceps femoris muscle, the renal muscle, and the spinal erector muscle.

In addition, by guiding the user to the correct posture for a long period of time, the user is less likely to get tired and the user's concentration can be maintained for a long period of time.

In addition, by maintaining the correct posture, you can train your postural muscles, hamstrings, and trapezius muscles in a well-balanced manner. You can create a well-balanced body that is less likely to get tired. Correcting your posture will also help you breathe easier.

In addition, according to the chair of the present embodiment, together with the material of cedar, the user is guided to a correct posture with the pelvis upright, and by maintaining this posture for a long time, the posture of the user is corrected and the posture muscles are strengthened. can be balanced. By sitting for a long time, the standing posture becomes well-balanced, and a well-balanced body that does not get tired even after walking for a long time can be created.

When the chair of this embodiment is used, the body remembers to sit in the correct posture, so even when using other general chairs, the user sits in the correct posture.

Therefore, when the chair of this embodiment is used in a waiting room of a hospital or a rehabilitation center, the patient can be efficiently placed in the correct posture. It is possible to reduce the labor of accompanying patients and nurses.

In addition, the chair according to this embodiment has the effect of regulating breathing and making the pelvis stand upright. It is said that if you raise your pelvis, your mind will become clearer, your independence will be established, and you will become healthier. In other words, as the mind becomes clearer, the head becomes clearer, one can concentrate on anything, the ability to make judgments, the acquisition of practical wisdom, the mind tightens, and one's motivation rises. As independence is established, the ability to concentrate, to be able to sustain, to work willingly, to be proactive, to be tenacious and to endure, and to acquire practical ability. To be healthy, correct posture eliminates pressure on the internal organs, eliminates anorexia, and makes movements more agile. According to the chair of this embodiment, since it exhibits an increase in concentration and a continuous effect, it can be expected to promote growth and improve scholastic ability by using it in a nursery school, school, or cram school.

Solid cedar wood is used for all materials constituting the chair 1 . By using cedar, it is possible to obtain the characteristics of cedar, such as moisture retention, heat retention, and antibacterial action. In addition to maintaining correct posture, the scent of cedar helps to recover from fatigue and relieve stress, and the earthing effect prevents poor health caused by static electricity. In particular, if the seat plate 19 is made of cedar wood, the moderate friction of the cedar wood contributes to the maintenance of the correct posture of the user for a long period of time.

With the chair of the present invention, the present inventors have aroused new demand for using solid cedar wood for chairs, which are familiar furniture. It is hoped that this tradition will be passed on to the composition.

1: Chair 10: Leg 11: Leg 12: Leg 13: Leg 14: Left lower support member 15: Right lower support member 16: Front support member 17: Rear support member 18: Left and right connecting member 19: Seat plate

Claims (5)

A chair having four legs provided on the front, back, left and right, and a seat surface, and is configured symmetrically in the front and back direction,
a plurality of seat plates forming the seat surface, the longitudinal direction of which is the front-rear direction of the user, and which are straight in the front-rear direction;
a front support member that supports the plurality of seat plates in a curve in which the seat surface protrudes downward and connects the front two legs out of the four legs;
a rear support member that supports the plurality of seat plates in a curved line in which the seat surface is convex downward and connects the rear two legs out of the four legs;
has
Curves in which the seat surfaces of the front support member and the rear support member are convex downward are
A chair that is a part of a bilaterally symmetrical ellipse convex downwards with respect to the longitudinal center of the front support member and the rear support member. A chair according to claim 1,
The chair, wherein the focal distance of the ellipse is the width of the seat in the left-right direction. A chair according to claim 1,
The curve in which the bearing surface is convex downward is
A chair in which the radius of curvature at both ends of the front support member and the rear support member is 1/5 or less of the width of the seat surface in the left-right direction. A chair according to claim 1 ,
Among the plurality of seat plates, the width of the seat plate near the center line of the seat surface is larger than the width of the seat plate near the left and right ends of the seat surface. A chair according to any one of claims 1 to 4 ,
A chair in which the seat plate is made of solid cedar wood.

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