JP6112768B2 - Seating device - Google Patents

Description

  The present invention relates to a sitting device such as a chair or a wheelchair, and in particular, while reducing the physical load at the time of sitting, the head can hold the sitting posture in a comfortable manner for a long time with the head facing the front. It relates to a seating device.

  First, the human trunk and lower limbs are connected via a pelvis, and the upper part of the pelvis is connected to the fifth lumbar vertebra by the sacral base and the lower part is connected to the femoral head by a joint with the acetabulum. The bones that make up the pelvis are the sacrum, the tailbone, and the left and right hipbones. The hipbone consists of three parts: the iliac bone, the pubic bone, and the ischial bone.

  When the person is in an upright posture (the posture in which the spinal column has a double S shape when viewed from the side), the pelvis is in a vertically stable shape with the ischia positioned at the lowest side. And the state where the ear holes, shoulders (shoulders), greater trochanter (bone at the base of the hip joint), slightly forward of the knee, and the external fruit (external ankle) are in a straight line, the beautiful posture (side) The posture in which the spinal column is drawn in a double S shape as viewed from above.

  Traditionally, the posture with the back stretched like when standing upright has been oriented as an ideal beautiful figure. For this reason, chairs have been made that maintain the stretched state of the back like an upright posture when sitting, by devising the position and angle of the seat and back.

  However, if sitting in this posture, a large load is applied to the sciatic bone, and a biased load is applied to a part of the buttocks contacting the seat surface. In addition, in order to maintain the same posture for a long time, extra muscular strength was required because of the impossible posture.

Therefore, in order to maintain a comfortable seating posture, for example, a low-resilience urethane resin is used to devise the cushion on the seating surface so as to be suitable for body pressure dispersion (see, for example, Patent Document 1). .), Chairs are known that employ a double-Russell structure or make a three-dimensional depression in the seat according to the shape of the buttocks.
However, even if the body pressure is dispersed, the load applied to the sciatica and lower back is not reduced only by devising the seating surface. It was not enough to solve the problem of becoming tired.

  In addition, there is a chair in which the shape of the backrest is curved so as to follow the S-shaped curve of the lumbar portion of the human spine and the S-shaped curve of the cervical vertebra (see, for example, Patent Document 2). However, it is a chair for holding the spine in an upright position even when sitting, so the pelvis is sitting in a state of being held vertically with the sciata positioned directly below, as in the upright position. In terms of local fatigue of the buttocks, it was still not enough.

Therefore, the inventor of the present application positively avoids a state where a load is applied to the lumbar part in the first place, and from the idea that it is effective to reduce the load on the lumbar part, a curved plate-like shape with the seating part side inside is used. A rear support having a non-fixed state attached to a base frame provided in a raised state at the rear of the seat, with the vicinity of both ends of the upper edge of the rear support as pivot points; An apparatus was invented (see, for example, Patent Document 3).
As a result, when the rear support is tilted, the lower edge thereof protrudes toward the seated person, and the load on the body part located above from the rib cage is received.

However, since the rotation fulcrum is near both ends of the upper edge, it is not necessarily optimal in the sense of avoiding load concentration at a specific location on the waist, and part of the cushion that contacts the back is aligned horizontally. It felt like a strong contact. That is, it is not suitable for the entire cushion of the rear support to be received as a soft and uniform surface, and it is not sufficient in that it is supported by the surface.
This is because when the tilting cushion comes into contact with the back, the load tends to concentrate near the rotation fulcrum shaft, and although the lower edge comes into contact with the overhang, it simply stays in contact, and the overhanging portion is the load. This is because it did not lead to the load being received in a well-balanced manner by the entire cushion.

  On the other hand, chairs that can tilt the backrest deeply so that you can recline the backrest so that you can support the torso comfortably are generally known, but if you lay your body in a reclining posture, you can get an easy state However, it is not a seating means suitable for daily life or work such as sitting on a chair and not suitable for such use. This is because, since the backrest is inclined in a plane, a person cannot view the front in a straight line with the skeleton stabilized.

In view of this, from the viewpoint of ergonomics, a chair has been devised which is referred to as a balance chair in which a seat part tilted forward and a knee abutment part positioned in front of the seat part are integrally connected (see, for example, Patent Document 4). .) This is because, in the sitting posture in which the upper body is kept vertical and the thighs of both legs are bent 90 degrees so as to be seated, the S-shaped curve of the spine is difficult to maintain, so By tilting forward 30 degrees, the S-shaped curved posture of the spine is maintained and it is easy to stand upright.
Certainly, the posture is corrected by extending the back muscles, and the load is distributed to the lower back and below the knees, which makes it difficult to get tired. However, because there is no backrest and the seating surface is tilted forward, it is suitable for use by healthy people, but it is difficult to achieve a comfortable chair that can be easily applied to a wide range of people including people with disabilities. In order to properly support the seat and the cushion under the knee, the interval must be finely adjusted according to the size of the human body.

  Therefore, the present inventor further considers the balance between the skeleton and muscle tension in terms of ergonomic differences in posture between standing and sitting, and the back is rounded when relaxed during sitting as follows. I found out that it was natural.

  First, when a person is standing in an upright position, the two muscles of the lower abdominal side, the iliopsoas muscle group, and the buttocks side, the gluteal muscle group, act as antagonistic muscles. The pelvis is firmly and stably held in the “standing position” where the sciatic bone is located directly under the tension that pulls each other across a stable joint. That is, when standing upright, the balance is established by the tension of the front and rear antagonist muscles, so that the posture can be easily maintained without using much muscle strength.

  By the way, when a person takes a sitting posture and the hip joint bends nearly 90 degrees, the “gastro-lumbar muscle group” on the lower abdomen side becomes closer because the positions of the lumbar vertebrae and the femur are close to each other. Tension is weakened because the muscles that had been loosened. On the other hand, the “gluteal muscle group” on the buttock side is extended so as to wrap around from the pelvis to the femur centering on the hip joint, so that a high tension is applied.

So, when these antagonistic muscles that support the pelvis in the sitting posture try to balance the tension, the pelvis that was in the “standing position” vertically with the sciatic bone in the standing position, Tilt to push out to become “tilted position”.
That is, the muscle tension in the standing posture in which the pelvis is stabilized in the vertical position acts as the muscle tension that tilts the pelvis around the hip joint in the sitting posture.

  Then, since the base pelvis is tilted, extra muscular strength is required to maintain the vertebral column including the lumbar vertebrae located above the pelvis in a straight S shape. Whether you are a healthy person or a disabled person, when you sit relaxed, your pelvis tilts naturally and your back becomes round accordingly.

  The inventor of the present application has attempted to develop a seating device for obtaining a natural sitting posture of the human body, and has invented a seating device that supports the back surface along the curvature of the back muscles (for example, (See Patent Document 5). However, with such a seating device, when sitting in an almost normal posture that does not take a supine state deeply, up to the action effect in the direction that actively avoids the load on the waist and reduces the load on the waist I do not have. In addition, if such a chair can be provided, it will be easy to maintain the posture and will not require muscle strength, however, in order to guide the natural sitting posture, the position and shape of the chair that will be the optimal sitting posture for each individual will be specified. Therefore, it has not always been easy to obtain an application immediately when each person uses it.

JP 09-51918 A JP 2006-75257 A JP 2011-139840 A No. 03-16518 JP 2007-307347 A

  One of the problems to be solved by the present invention is that the posture is such that the head of the human body is directly facing the front in front of the human body, while assuming that the pelvis is in an inclined position when seated. It is to provide a seating device that can be maintained comfortably for a long period of time and is suitable for both healthy and disabled people.

  When sitting with the pelvis tilted in consideration of the balance of muscle strength, it is desirable that the buttocks move forward. However, since it comes to be seated on the near side of the chair, it becomes a so-called posture with a normal chair, and in that case, the load on the back side is greatly applied to the seat side. As a result, a large load is applied to a part of the seating surface, and the seating posture cannot withstand long-time use.

Further, in order to achieve a posture in which the head is directly facing the front in front with the pelvis tilted, the posture is different from that in the upright state where the spinal column has an S shape. Therefore, since it is a way of applying a load due to a change from the upright position, it is required to provide a back support that matches the difference.
Furthermore, the inventor of the present application has found that when the fulcrum shaft of the backrest is positioned on the extension line between the center of the second lumbar vertebra and the third lumbar vertebra of the human body, the load can be evenly applied to the backrest and seated without any sense of incongruity.

  Therefore, one of the problems to be solved by the present invention is to sit down at a position where the buttocks moved slightly forward and hold the body on the back side, and support it at an appropriate position from the back side, thereby supporting the sternum. Applied to various forms such as chairs and wheelchairs that can distribute the load on the upper back evenly on the back side of the back and also distribute the load on the seat surface of the buttocks, reducing local concentration It is to provide a seating device that can be used.

  Means for Solving the Problems In the first means, the first means includes a seating portion supported by the frame, and an upper column supported by the frame on the back side of the seating unit, and the horizontal column is placed on the upper column. A seating device provided with a curved waist support portion that is provided with left and right rotation shafts with the direction as an axial direction and is supported by the left and right rotation shafts so as to be rotatable and tiltable. Has a contact surface for supporting the human body on the curved inner surface, and the central portion of the curved inner surface of the corresponding contact surface is a closest position point within a radius of 2 cm from the fulcrum axis line connecting the left and right rotation axes. And the height of the upper end of the center portion of the contact surface is 4 to 8 cm higher than the height of the fulcrum axis at a position where the curved inner surface of the contact surface is upright. .

  The second means includes a seating portion supported by the frame, and an upper support supported by the frame on the back side of the seating portion, and the left and right rotation shafts having a horizontal direction as an axial direction are provided on the upper support. A seating device provided with a curved waist pad portion supported by the left and right rotation shafts so as to be rotatable and tiltable, wherein the curved waist pad portion supports the human body on the curved inner surface. When the height of the rotary shaft provided on the upper support is in contact with the waist of the human body seated by tilting and rotating the waist pad, the left and right sides of the waist pad The seating device is characterized in that the fulcrum axis line connecting the rotation axes of the two is positioned so as to be close to a distance within 2 cm from the intervertebral disc plane between the second lumbar vertebra and the third lumbar vertebra of the seated human body.

  Further, in the third means, the upper support column is provided with an adjustment mechanism capable of changing the horizontal height position of the rotating shaft up and down, and the height of the waist pad portion can be changed to a predetermined position and can be pivotally supported. A seating device according to claim 1 or claim 2, characterized in that.

  The fourth means includes a seating portion supported by the frame, and an upper column supported by the frame on the back side of the seating unit, and the upper column is provided with left and right rotation shafts with the horizontal direction as the axial direction. A seating device provided with a curved waist pad portion supported by the left and right rotation shafts so as to be rotatable and tiltable, wherein the curved waist pad portion supports the human body on the curved inner surface. When the height of the rotary shaft provided on the upper support is in contact with the waist of the human body seated by tilting and rotating the waist pad, the left and right sides of the waist pad The fulcrum axis connecting the two rotation axes can be changed up and down so that it can be positioned close to a distance of 2 cm or less from the intervertebral disc plane between the second and third lumbar vertebrae of the seated human body. And a central portion of the curved inner surface of the corresponding contact surface The height of the upper end of the center of the contact surface at the position where the closest contact point is at a position within a radius of 2 cm from the fulcrum axis connecting the left and right rotation axes and the curved inner surface of the contact surface is upright Is a seating instrument characterized by being 4 to 8 cm higher than the height of the fulcrum axis.

  According to the present invention, a healthy person or a handicapped person sitting in a chair or a wheelchair keeps his / her comfortable and comfortable posture so that his / her back is brought into contact with his / her hip rest, and the upper body (mainly above the sternum) ) Can be placed evenly on the waist rest, so that the sitting posture can be maintained while the front can be viewed. And since the load concerning the seating surface of a seating part can be disperse | distributed and it can avoid that a load concentrates locally, it becomes suitable for sitting for a long time.

  By setting the height of the upper end of the abutment portion to an appropriate height so that the upper end of the abutment surface of the waist pad is defined as the first means, the body pressure due to the load applied from the upper body to the waist is equalized. Thus, local concentration can be avoided more easily.

  Also, by positioning the height of the rotating shaft as in the second means, the optimal seating position that is less likely to get tired can be accurately determined, so that body pressure is naturally distributed properly when sitting, It is possible to simply provide a seating device suitable for use.

  In addition, if the height of the rotary shaft can be adjusted easily as in the third means, it is possible to easily position the waist rest correctly on the waist, so that the optimal seating position that is more comfortable and comfortable can be obtained. It becomes possible to provide a seating device. Further, by combining the first means and the second means as in the fourth means, it is possible to more accurately define the positional relationship of the abutting surfaces that abut the waist, so that the dispersion of body pressure is ensured. As a result, it is possible to provide a seating device that is more comfortable and can be used for a long time.

It is the perspective view which looked at the chair of the seating instrument of this invention from the plane, the back, and the left side. It is the figure which looked down at the chair of the seating instrument of this invention from the back upper side. It is a figure which shows the positional relationship of the fulcrum axis line of the seating instrument of this invention, and the center part of a contact surface. It is a figure which shows the positional relationship of the height of the upper end and instruction | indication axis line when the contact surface of the seating instrument of this invention stands upright perpendicularly | vertically. It is a figure which shows the position of the instruction | indication axis line of the seating instrument of this invention, and the positional relationship of the disc plane between the 2nd lumbar vertebra and the 3rd lumbar vertebra. It is the perspective view seen from the left side upper surface of the chair of the seating instrument of this invention. It is a figure of the measurement result which shows a mode that the body pressure disperse | distributes when sitting on the seating instrument of this invention. (1) indicates the pressure applied to the seat surface, and (2) indicates the pressure applied to the back surface. It is a figure of the measurement result which shows the change of the body pressure when changing the position of the waist pad part of a sitting instrument. It is a figure of the measurement result which shows the change of the body pressure when changing the position of the waist pad part of a sitting instrument. It is a figure of the measurement result which shows the change of the body pressure when changing the position of the waist pad part of a sitting instrument. It is a figure of the measurement result which shows the change of the body pressure when changing the position of the waist pad part of a sitting instrument. It is a figure of the pressure measurement result at the time of seating about the chair which aimed at provision of the comfortable posture called an easy seat as the comparative example 1. FIG. (15) is the back surface, and (16) is the pressure applied to the seat surface. It is a figure of the pressure measurement result at the time of sitting on the chair leap of STEELCASE as the comparative example 2. (17) indicates the pressure applied to the back surface, and (18) indicates the pressure applied to the seat surface. It is a figure of the pressure measurement result at the time of sitting on the wheelchair made from a Panthera company as the comparative example 3. FIG. (19) indicates the pressure applied to the back surface, and (20) indicates the pressure applied to the seat surface.

Hereinafter, the case where the embodiment of the present invention is applied to a chair will be described as appropriate with reference to FIGS.
First, the seating device of the present invention is mainly fixed to a seating part for placing a hip of a human body, a frame-like frame body that supports and fixes the seating part at a height below the knee, and a frame on the back side of the seating part. The seating device is provided with an upper strut that is formed and a waist rest that is pivotally supported by a rotation shaft provided above the upper strut. The seating device may be a chair used in combination with a general desk or table, or may be a seating device that can be cast as a lowermost part of the frame or can be moved as a wheelchair.

  The frame of the present invention can be appropriately selected from metal, wood, plastic resin, etc., as long as it has an appropriate strength that can withstand the load caused by the operation of a person standing or sitting. In other words, the part that becomes the leg is formed skeletally. This is a frame frame formed by combining a plurality of pipes and wood having a circular, oval or rectangular cross section. The members of the frame have a frame shape that is firmly fixed by bending, welding, fastening with bolts, adhesion, joints with mortise and tenon, etc., and the frame as a whole can fully support the load It has become.

  Above the frame body, there is provided a seat for placing a human buttock, which is supported and fixed by the frame. The seating portion may be a single wooden board or a cushioning material such as polyurethane foam at the contact portion of the heel portion. An upper column for pivotally supporting the waist rest portion is supported and fixed to the frame on the back side of the seating portion. This upper support column may be two support columns formed upward from the left and right frame positions on the back side, or one upper support column provided upward from the center of the frame on the back side. . In addition, any upper column may be fastened and fixed with a frame and screws or bolts, or the frame and the upper column may be integrally formed.

  The waist rest part of the seating device can be rotated and tilted in the horizontal direction with the support axis line connecting the left and right rotating shafts as a tilting axis while being supported by the left and right rotating shafts provided at the upper end of the upper support column. It has a structure. When this upper support column is composed of two left and right, the rotation shaft provided at the upper end on the inner surface facing each of the left and right upper support columns can be rotated and tilted by sandwiching the waist pad from both sides. Will be supported. In addition, when there is only one upper support, the load is supported by bifurcating the upper part of the upper strut and pinching the waist pad so that it can be rotated and tilted by holding it with both left and right rotating shafts. Will be.

  As an embodiment of the seating device of the present invention, FIG. 1 shows a frame body of a wooden frame 2, and a chair 1 provided with cushions of cushioning members 5 on the seating portion 3 and the waistrest portion 4, respectively. The wooden frame 2 of the chair 1 is made up of chamfered end-face rectangular squares having a thickness of 2 to 3 cm and a width of 4 to 5 cm. The frame 2 is configured as a frame. The seating portion 3 is composed of a bottom plate and a cushioning member 5 made of polyurethane foam material having an exterior surface covered with a woven fabric on the upper portion thereof. The top plate of the seating portion 3 and the frame 2 are fastened with bolt screws, and the seating portion 3 is fixedly supported. As the polyurethane foam, it can be said that the use of a low-repulsion foamed polyurethane foam having a high density and a low repulsive force is preferable for dispersion of body pressure. However, even if the seating portion is a hard plate material made of a simple wooden top plate, in the present invention, body pressure dispersion can be appropriately achieved, so that even if used, there is no immediate problem.

  In the waist pad portion 4 of FIG. 1, the inner surface side gently curved in an arc shape becomes the contact surface 6 and comes into contact so as to wrap around the waist portion of the back of the human body. The contact surface 6 on the inner surface side of the waist pad portion 4 is provided with a buffer member 7 containing a foamed polyurethane foam material inside the outer surface covered with a fabric. The waist pad 4 receives the load applied to the upper body from the waist when contacting the human body, and supports the body pressure while dispersing not only the buttocks but also the waist. Note that the abutting surface 6 does not necessarily need to include the buffer member 7, and only the curved plate material may be used as the waist rest portion 4.

  The waist pad portion 4 is pivotally supported on the rotary shafts 10 and 10 provided to face the inner surface side of the upper end portions 9 of the left and right upper columns 8 rising upward from the back side of the frame 2. The waistrest portion 4 tilts with the horizontal fulcrum axis 11 connecting the left and right rotating shafts 10 and 10 as the rotating shaft 12. That is, when the waist part comes into contact with the contact surface 6, the waist pad part 4 is tilted around the rotation shaft 12 so that the lower part is on the front side and the upper end 13 is on the back side. The rotary shaft 10 has a structure that supports the main shaft of the waist pad 4 using a general rolling bearing. However, the main shaft can be formed into a circular hole in the upper support column without using the rolling bearing. You may rotate by inserting.

  Further, the central portion 14 of the curved inner surface of the contact surface 6 of the waist pad portion 4 is the closest position within a radius of 2 cm from the fulcrum axis 11 when observed from the direction of the rotation axis (that is, from the side of the chair 1). It has a point 15. That is, the central portion 14 of the curved inner surface of the contact surface 6 is located near the fulcrum axis 11. In FIG. 3, the central portion 14 of the curved inner surface of the contact surface 6 is positioned so as to substantially overlap the fulcrum axis 11. As a result, when the waist pad 4 is tilted, the waist is supported without shaking the load on the waist around the fulcrum axis 11, so that the back can be swung by tilting lightly. Therefore, the human body can be supported comfortably without causing discomfort when swinging.

  Further, the upper end 13 of the curved inner surface of the abutment surface 6 of the waist pad 4 is 4 to 8 cm higher than the height of the fulcrum axis 11 in a state where the curved inner surface is upright. Is in position. In other words, the waist pad portion 4 does not tilt in the form of hanging downward from the position of the rotating shaft 10 but protrudes at a height 15 of 4 to 8 cm further upward than the height of the rotating shaft 10, so that the balance Can tilt well. And when the upper end 13 of the abutment surface 6 tilts backward to the back side, the upper end supports the waist part of the back of the human body slightly above, so rather than simply supporting from directly above the fulcrum axis 11 It becomes easy to disperse without concentration of load. FIG. 4 shows that the height 15 of the upper end 13 at the center of the abutting surface 6 is 4 to 8 cm higher than the height of the fulcrum axis in a state where the waist pad 4 is vertical.

  As described above, the central portion 14 of the curved inner surface of the abutting surface 6 tilts at a position close to the fulcrum axis 11 (within 2 cm), and in addition, the height of the upper part of the waist pad when standing is the height of the fulcrum axis. Because it has a shape that is 4-8 cm higher than the height, when it is tilted, it can support the load of the waist more widely and in a balanced manner, so that the load from the waist support is evenly applied to the fulcrum axis. Therefore, it is suitable for dispersion of body pressure.

  FIGS. 7 to 14 are diagrams of measurement results of pressure distributions measured under various conditions with respect to the difference in how the load is applied when a person is seated on the seating device of the present invention and the comparative example. These measurements were conducted under the guidance of Assistant Professor Tadahiko Kagaya of Department of Occupational Therapy, Department of Occupational Therapy, Gunma University School of Health Sciences. Each pressure is displayed in shades from black to white. Black is the part with the lowest pressure, and white indicates the part with the highest pressure. A measurement sheet having a large number of pressure sensors arranged on the entire seat surface was placed on the seat surface or the back surface, and a person was seated on the measurement sheet.

  The pressure notation in FIGS. 7 to 14 is indicated by mmHg because the measurement result of the measuring device is shown as it is. In terms of SI units, black 5 mmHg corresponds to approximately 667 Pa, 100 mmHg corresponds to 13,332 Pa, 130 mmHg corresponds to 17,332 Pa, 150 mmHg corresponds to 19,998 Pa, and 200 mmHg corresponds to 26,664 Pa. The white color of 200 mmHg or higher is only displayed in white because of the measurement limit.

  In addition, 200 mmHg is generally said to cause pressure ulcers in a few minutes, and maintaining the posture as it is for a long time causes a so-called bed slip, so it is not at all suitable for long use as a chair. It shows that it is in a state. In particular, when it is viewed as a sitting device applied by persons with disabilities who cannot independently change their posture independently, it can be said that there are many problems where pressure is concentrated.

  First, FIG. 7 illustrates the result of measuring the state of body pressure dispersion when sitting on the seating device of the present invention. (1) is a seat surface, (2) is a figure of the pressure concerning a back surface. 8 to 11 show how the load is applied to the waist pad according to the present invention and when the waist pad 4 is located outside the range defined by the present invention. The state of the pressure change applied to 4 is sequentially illustrated. That is, the difference in height between the upper end 13 of the central portion 14 of the curved inner surface of the abutting surface 6 of the waistrest portion 4 and the position of the indicated axis 11 is measured as shown in FIG. When the height is 15, the state where the value of height 15 is +6 cm is the standard position 0. FIG. 7 shows the measurement at the standard position 0.

  FIG. 8 shows the waist pad 4 in the case where the height of the upper end 13 of the central portion 14 of the curved inner surface is increased upward at the position where the contact surface 6 of the waist pad 4 is vertically raised. It is the figure which showed the mode of the change of the pressure concerning. The results are obtained at a position where (3) is +10 mm, (4) is +20 mm, and (5) is +30 mm with respect to the standard position 0.

  FIG. 9 shows the state of pressure change when the height of the upper portion of the waist pad portion 4 is lowered and the height 15 is changed in the direction of decreasing. (6) is the result of −10 mm, (7) is −20 mm, and (8) is the result of −30 mm with respect to the standard position 0.

  From the results of FIGS. 7 to 9, it is confirmed that the load is concentrated below the waist pad portion 4 as the height is increased, and the load is concentrated above the waist pad portion 4 as the height is decreased. It was confirmed that the height of the upper end of the waist rest part 4 was important. That is, with respect to the value of the height 15 related to the position of the waist pad portion 4, the body pressure is generally dispersed up to 20 mm above and below the standard position 0 (the value of the height 15 is 6 cm). I understand that. Particularly, up to 10 mm above and below, the body pressure is dispersed on average, which is a preferable state. Therefore, as the value of the height 15, 4 to 8 cm exhibits the effects of the present invention, and 4 to 7 cm is particularly preferable.

  In addition, as for the feeling of fatigue and discomfort when sitting, under the conditions of (2), (3) and (6), the body pressure is evenly distributed and the sense of discomfort is recognized as the weight is firmly laid on the waist rest part 4. I couldn't. On the other hand, in the case of (4), it feels that a load is applied to the lower part of the waist pad portion 4 slightly, and in the case of (7), it feels that a load is applied to the upper part slightly, but the feeling of getting on the weight is obtained. It was. On the other hand, in (5), the load was felt extremely downward, and in (8), the load was felt extremely upward, and the sense of weight gain was lost.

  From the above results, the “position where the curved upper surface of the contact surface is upright and the height of the upper end of the central portion of the corresponding contact surface is 4 to 8 cm higher than the height of the fulcrum axis” of the present invention is useful. And “a position where the height of the upper end of the center portion of the contact surface is 5-7 cm higher than the height of the fulcrum axis at a position where the curved inner surface of the contact surface is upright” is particularly suitable and can achieve excellent body pressure dispersion. Was confirmed.

  10 and 11, when the chair 1 is observed from above, the central portion 14 of the curved inner surface of the contact surface 6 of the waist pad portion 4 in the vertical orientation is directed to the indication axis 11 that connects the left and right rotating shafts 10. On the other hand, it is the figure which measured a mode that the pressure of body pressure dispersion | variation changes at the time of separating ahead or back.

(2) in FIG. 7 is the standard position, and the separation distance is zero. When the separation to the front side is represented by + and the separation to the back side is represented by −, FIG. 10 is separation to the back side, (9) is −10 mm, (10) is −20 mm, and (11) is −30 mm. It is. Further, FIG. 11 is separated from the front side, and (12) is +10 mm, (13) +20 mm, and (14) +30 mm.
When the waist pad portion 4 is moved to the front side, the experiment of FIG.

  From the results of FIG. 10 and FIG. 11, body pressure dispersion is generally well achieved from (2) to (9) and (12), that is, from a separation distance of 0 to 10 mm before and after that. Although it was confirmed, in (10), (11), (13), and (14) where the separation distance becomes larger than that, the white color was gradually shown in the upper part of the contact surface 6 of the waist pad 4. It was confirmed that a high pressure part was recognized, the body pressure was not sufficiently dispersed, and a large load was applied to a part of the back surface, particularly above the waist.

In addition, as for the feeling of sitting and feeling of fatigue and discomfort, (2), (9) and (12), the body pressure was evenly distributed and the feeling of discomfort was recognized as the weight rested firmly on the waist pad 4. I couldn't. On the other hand, in the cases of (10) and (13), although the sensation of being in contact with the abutting surface 6 of the waist rest part 4 was slightly weakened over the entire surface, the sense of support of the contact area was slightly reduced. It was confirmed that the weight was on the contact surface 6 of the waist pad 4.
On the other hand, in the case of (12) and (14), the feeling of touching with a line was remembered, and the feeling of overall support was lost, and the user felt uncomfortable.

  From the results of FIGS. 7, 10, and 11, the central portion of the contact surface 6 of the curved inner surface of the waist pad 4 is “closest to a position within a radius of 2 cm from the fulcrum axis 11 that connects the left and right rotating shafts 10. In the case of “having a dot”, the body pressure was dispersed, which proved useful. In particular, when the center portion of the contact surface 6 of the curved inner surface of the waist pad portion 4 has “the closest position point at a position within a radius of 1 cm from the fulcrum axis 11 connecting the left and right rotating shafts 10”, It was found that body pressure dispersion was achieved evenly and more suitable.

On the other hand, the measurement result about the pressure about the various chairs which aimed at the comfort of the other company's product is illustrated in FIGS. 12-14 as Comparative Examples 1-3.
Fig. 12 shows the result of an experiment on a general easy chair sold by domestic mail order sales. The body pressure applied when seated on the product name "Rakuza Chair" made by Japan New Furniture (15) ( 16). Looking at (16), it can be seen that a white part is recognized very widely in the buttocks of the seating surface, and an extremely high pressure is applied to the seating surface as it is. Since the white part is extensive, it can be said that a congested part is likely to occur, and strongly suggests that it is not adapted to use for a long time.

  FIG. 13 shows the result of pressure measurement when sitting on a chair / leap chair of STEELCASE. As shown in (18), four locations at the center of the seating surface and a location showing pressure concentration of 150 mmHg or more were recognized.

  Comparative Example 3 in FIG. 14 shows the results when seated on a wheelchair made by Panthera, Sweden. A white spot showing extremely high pressure concentration on both the left and right sides is recognized behind the buttocks on the seat surface side of (20). From this, it can be said that it is not always preferable to sit on the seat as it is when the handicapped person is extremely disabled.

  Moreover, the chair 1 which is other embodiment makes the waist pad part 4 tilt-rotate the height position of the rotating shafts 10 and 10 of the waist pad part 4 so that the effect of dispersion | distributing body pressure can be exhibited suitably. The fulcrum axis 11 connecting the left and right rotation shafts 10, 10 of the waist rest portion 4 when in contact with the lumbar portion of the seated human body is in contact with the second lumbar vertebra L2 and the third lumbar vertebra of the seated human body. The chair 1 is positioned close to a distance within 2 cm from the intervertebral disc plane 16 of the L3 vertebra. That is, it is the chair 1 provided with the waistrest part 4 in which the separation distance of the support axis from the intervertebral disc plane is within 2 cm.

  When the boundary plane between the second lumbar vertebra L2 and the third lumbar vertebra L3 is the intervertebral disc plane 16, the intervertebral disc plane 16 is a plane that intersects perpendicularly with a straight line connecting the second lumbar vertebra L2 and the third lumbar vertebra L3. In order to move the support axis 11 connecting the left and right rotating shafts 10 and 10 in the linear direction connecting L2 and L3, that is, in the direction of the arrow indicating the distance from the intervertebral disc plane, The position of the rotary shaft 10 and the position of the rotary shaft 10 are changed in advance, or an adjustment mechanism 19 for adjusting the height is provided between the upper support column 8 and the frame 2, and the rotary shaft 10 and the support axis 11 are stepwise or steplessly provided. This can be realized by making it possible to change the horizontal height position.

  In particular, the horizontal height adjusting mechanism 19 is appropriately selected in a stepwise manner, for example, by providing a slider or a notch at an interval of 1 mm in advance, or by fixing a bolt by inserting a bolt into a prepared hole. it can. The adjusting mechanism 19 that can freely slide between the upper support column 8 and the frame 2 may be slid steplessly, so that the upper support column 8 and the frame 2 are in strong contact with each other so as not to move. It is also possible to use a mechanism in which the entire surface is brought into contact with a bolt and tightened with bolts.

When the intervertebral disc plane 16 between the second lumbar vertebra L2 and the third lumbar vertebra L3 and the separation distance 17 of the support axis 11 from the intervertebral disc plane 16 are within 2 cm, the support axis 4 Since the load applied around 11 is distributed evenly as a whole, the user does not feel a sense of incongruity due to the body pressure applied to a part of the user. Therefore, even if used for a long period of time, it can be used comfortably, and the front can be easily viewed.
On the other hand, if the support axis 11 is too far away from the intervertebral disc plane 16 between the second lumbar vertebra L2 and the third lumbar vertebra L3, which is the central position of the lumbar vertebra, the effect of the present invention that the lumbar part is supported and supported from below is sufficiently obtained Not exerted, body pressure concentrates in part, and the waist is fatigued.

  In addition, since it is desirable to fit the waist rest portion 4 to the waist portion, even in the first means, if the height can be easily adjusted according to the person sitting, as a versatile chair, It will be easy to market. Therefore, an adjustment mechanism that can adjust the height of the upper column may be provided.

  Further, as in the fourth means, the waist pad shown in the first means can be applied to the position described in the second means and applied in combination. As a result, an evenly balanced waist pad can be applied to a more appropriate position, and a chair that is less likely to get tired can be provided very simply.

DESCRIPTION OF SYMBOLS 1 Chair 2 Frame 3 Seating part 4 Lumbar rest part 5 Buffer member 6 Contact surface 7 Buffer member 8 Upper support | pillar 9 Upper end part 10 Rotating shaft 11 Support axis 12 Rotating shaft 13 Upper end 14 Center part of curved inner surface 15 Height 16 Intervertebral disk plane 17 Spacing distance of support axis from intervertebral disc plane 18 Torso 19 Adjustment mechanism L2 2nd lumbar vertebra L3 3rd lumbar vertebra

Claims (3)

  A seating portion supported by the frame; and an upper support supported by the frame on the back side of the seating portion, the left and right rotation shafts having a horizontal direction as an axial direction are provided on the upper support, and the left and right rotation shafts A seating device provided with a curved waist pad portion that is pinched by and pivotally supported so as to be rotatable and tiltable, the curved waist pad portion having a contact surface for supporting a human body on the curved inner surface, When the height of the rotary shaft provided on the upper column is brought into contact with the waist of the human body seated by tilting and rotating the hip pad, the left and right rotary shafts of the hip pad are connected. A seating device in which the fulcrum axis is positioned so as to be close to a distance within 2 cm from the intervertebral disc plane between the second lumbar vertebra and the third lumbar vertebra of the seated human body.   The upper support column includes an adjustment mechanism capable of changing the horizontal height position of the rotary shaft up and down, and can change the height of the waist pad portion to a predetermined position and pivotally support it. A seating device as described in 1. A seating portion supported by the frame; and an upper support supported by the frame on the back side of the seating portion, the left and right rotation shafts having a horizontal direction as an axial direction are provided on the upper support, and the left and right rotation shafts A seating device provided with a curved waist pad portion that is pinched by and pivotally supported so as to be rotatable and tiltable, the curved waist pad portion having a contact surface for supporting a human body on the curved inner surface, When the height of the rotary shaft provided on the upper column is brought into contact with the waist of the human body seated by tilting and rotating the hip pad, the left and right rotary shafts of the hip pad are connected. An adjustment mechanism that can be changed up and down so that the fulcrum axis can be positioned close to a distance within 2 cm from the intervertebral disc plane between the second and third lumbar vertebrae of the seated human body, And the central part of the curved inner surface of the corresponding contact surface is the left and right rotation It has a closest position point with respect to the pivot axis to a position within a radius 2cm from connecting it fulcrum axis a, and fulcrum height of the upper end of the central portion of the abutting surface at a position where the curved inner surface of the contact surface is upright A seating device having a position 4 to 8 cm higher than the height of the axis.