JP6860967B2 - Back pain measures chair - Google Patents

Description

The present invention relates to a chair for the purpose of preventing low back pain that occurs in a sitting position for a long time.

Many people complain of back pain in occupations that require long hours of desk work. The causes of low back pain caused by sitting for a long time are considered to be disc pain, back muscle pain, and buttock compression pain due to persistent lumbar kyphosis.

There are also chairs (balance chairs) in which the backrest of the chair is padded for the purpose of reducing lumbar kyphosis, the backrest is tilted down, and the chair is supported by the knees. In order to reduce the pain in the buttocks caused by long-term compression of the buttocks, some chairs use a low-resilience material for the cushion of the seat surface or have a curved seat surface that matches the shape of the back of the thigh and the buttocks. However, if the back muscles are left in an immobilized state for a long time in the same posture for a long time, blood flow to the muscles is stagnant even when the load is light, causing accumulation of lactic acid and causing dull pain. Furthermore, the facet joints and intervertebral discs, which are nourished by diffusion rather than blood flow, are adversely affected because their diffusion is poor due to the continuous same posture.

There are many chairs in which the backrest can be tilted or the height of the seat can be changed, and the sitting posture can be changed by these movements, but the posture for desk work is naturally suitable for the work. Since it is limited to height, it is not realistic to move it frequently. There are chairs with a rocking mechanism and chairs such as Patent Document 1 in which the seat plate can change the inclination angle in the front-rear direction, but the same is true. In addition, the posterior tilt of the seat increases pressure on the back and back, causing back pain. In addition, the forward inclination of the seat surface causes the buttocks to slide down.

In an agitated chair or a balance ball as in Patent Document 2-4, the seat surface moves and balances in an unstable manner, so that the back muscles are constantly strained and cause muscle fatigue. As in Non-Patent Document 1, there is a chair that passively tilts the seat surface with a constant rhythm by a motor, but it is not possible due to the forced muscle tone caused by posture control due to movements unrelated to one's own intention. With pleasure. Furthermore, in the human body, the lower limbs, pelvis, and lumbar spine are closely related, and the movements of the pelvis and lumbar spine without lower limb movement are not natural movements.

Some chairs, such as Patent Documents 5 and 6, have a seating surface divided into left and right, and the space between them can be changed or the chair can be shaken independently. In addition, as in Patent Document 7, a chair in which the seat surface is divided into left and right and the left and right move up and down in conjunction with each other has been devised. These are intended to improve the fit between the seat surface and the pelvic thigh of the seated person by shaking the seat surface independently on the left and right, but the relaxed posture and walking when the legs are crossed as described later. It is not possible to perform the same quality of movement of both lower limbs-pelvis-lumbar spine as time.

JP-A-2014-46132 JP-A-2005-58719 JP 2006-68223 Japanese Patent Application Laid-Open No. 2008-86614 Patent No. 4546957 JP-A-2005-52317 Japanese Patent Application Laid-Open No. 10-151033

Yuta Chinen, Examination of seat tilt pattern in lumbar load improvement system using chair that can actively tilt seat, Proceedings of 2014 Spring Meeting of the Japan Society for Precision Engineering

You can relax by crossing your legs while sitting. When the legs are crossed, there is a laterality in the flexion angle of the hip joint. Along with this, as shown in FIG. 1, the pelvis 1 is slightly tilted laterally (pelvic lateral tilt), the lumbar spine 2 is scoliotic, and the length of the back muscle 3 is shortened on one side and stretched on the other side, and muscle tone is relieved. To. The intervertebral discs and facet joints also move, and the diffusion of oxygen and nutrients in the same area is promoted. However, crossing the legs for a long time causes discomfort due to the pressure between the legs. The purpose of this invention is to realize the same relaxed posture as when the legs are crossed without the legs crossing each other. In addition, low back pain caused by sitting for a long time is further improved by walking, but the interlocking movements of both lower limbs-pelvis-lumbar spine associated with walking bring about relaxation of systemic muscle tone and improvement of blood flow. It is also an object of this invention to reproduce this with a chair.

In the chair of the present invention, the left and right seat surfaces are interlocked and tilted back and forth alternately, and when one lower limb is extended, the seat surface portion of that one is tilted forward due to the acting force, and the other seat is interlocked with it. The face is tilted backwards and the hip joint of the other lower limb is in a flexed position. This can be done alternately on the left and right.

There is a difference in flexion between the left and right hip joints, and the pelvis is slightly tilted and the lumbar spine is curved, causing movement of the back muscles. This is a relaxed posture similar to when the legs are crossed, although the legs are not crossed, and the back muscle tension can be relaxed. When it is repeated alternately on the left and right, it becomes the same as the interlocking movement of both lower limbs-pelvis-lumbar spine performed during walking, and the harmful effects associated with the continuous same posture are eliminated and the back pain is relieved. The pressure pain is relieved by a large change in the weighting status of the buttocks and thighs on the seating surface. Rather than being upset in multiple directions, it is active and causes specific movements, and there is little discomfort. Since the seat surface tilts forward and backward at the same time, it does not slip off. It does not interfere with desk work while moving.

Schematic diagram of the pelvic lumbar spine. a: When the pelvis is tilted to the left b: Intermediate position c: When the pelvis is tilted to the right. Top view of the seating surface of the embodiment of the present invention. The whole side view of Embodiment 1 of this invention. Bottom view of Embodiment 1 of the present invention. (Cut at a high position on the base) The front view of the interlocking apparatus of Embodiment 1 of this invention. Dynamic side view of Embodiments 1 and 2 of the present invention. a: When the left leg is extended b: When the right leg is extended The whole side view of Embodiment 2 of this invention. Bottom view of Embodiment 2 of the present invention. (Cut at a high position on the base) Bottom view of the interlocking device according to the second embodiment of the present invention. (Cut the outer wall) The front view of the interlocking apparatus of Embodiment 3 of this invention. The dynamic side view of Embodiment 4 of this invention. a: When the left leg is extended b: When the right leg is extended

Embodiment 1 is a reference example will be described with reference to FIGS. 2a, Figure 3-6. As shown in FIG. 2a, the seat surface in contact with the buttocks and thighs when a person sits is divided into left and right on the front side, and is composed of a left seat surface portion 4, a right seat surface portion 5, and a rear seat surface portion 6. There is a base 7 that supports the seat surface. There is a leg 8 under the base 7. There is a backrest 9 at the back. The rear seat surface portion 6 is fixed to the base portion 7 by the rear support member 10. The horizontal support shaft 11 having an axial structure having a long axis in the left-right direction is located on the lower surface of the rear end portion of the left and right seat surface portions 4, 5, and the bearing 111 and the horizontal support shaft 11 fixed to the left and right seat surface portions 4, 5 are Connected, the horizontal support shaft 11 is fixed to a stopper 15 continuous with the base 7. With this structure, the left and right seat surfaces 4 and 5 can be tilted back and forth, respectively. The tilt angle is limited by the stopper 15. There is a bar 12 having a long axis in the left-right direction, and the bar 12 is connected to the lower parts of the left and right seat surfaces 4 and 5 via the arm 13. There is a vertical support shaft 14 having an axial structure having a long axis in the front-rear direction, and the vertical support shaft 14 is fixed to a stopper 15 continuous with the base portion 7. The bar 12 and the vertical support shaft 14 are connected at the center of the bar 12. Due to these structures, the left and right seating surfaces 4 and 5 are interlocked and tilted back and forth alternately as shown in FIG.

Embodiment 2 Ru specific embodiments der of the present invention will be described with reference to FIG. 2a, FIG. 6-9. The second embodiment is a gear type reversing device 17 in which the interlocking device has four bevel gears 16 as shown in FIG. 9, and they are combined at orthogonal positions, and the left and right horizontal support shafts 11 are reversed. The gear type reversing device 17 is located on the lower surface of the trailing edge portion of the left and right seat surface portions 4, 5, and the horizontal support shafts 11 protruding to the left and right from the gear type reversing device 17 are fixed to the left and right seat surface portions 4, 5. It is fixed at 112. The gear type reversing device 17 is fixed to a stopper 15 continuous with the base 7. It is the same as the first embodiment except around the interlocking device. Due to these structures, the left and right seating surfaces 4 and 5 are interlocked and alternately tilted back and forth as shown in FIG. The tilt angle is limited by the stopper 15.

The interlocking device is the same as that of the first embodiment except for the interlocking device, but a structure in which the interlocking device is composed of a lateral arm 18, an oblique arm 19, and a bar 20 fixed to the base portion 7 as shown in FIG. 10 can be considered ( reference). Example 3). As described above, the left and right seat surfaces 4 and 5 are interlocked and tilted back and forth alternately.

The basic elements of the seat surface are as shown in FIG. 2b, in addition to the above-described first and second embodiments, which are composed of the left seat surface portion 4, the right seat surface portion 5, and the rear seat surface portion 6 as shown in FIG. 2a. A form composed of two seating surfaces, a left seating surface 41 and a right seating surface 51 (Embodiment 4), is also conceivable. In the fourth embodiment, the configurations other than the seat surface are the same as described above, and as shown in FIG. 11, the left and right seat surface portions 41 and 51 are interlocked and alternately tilted back and forth.

Claims (2)

In a chair that has a seat surface that is the part where the thighs contact from the buttocks of the seated person and a base that supports the seat surface.
The seat surface is divided into left and right at least in the front part of the seat surface, and the basic elements of the seat surface are composed of the left seat surface portion and the right seat surface portion, or the left seat surface portion, the right seat surface portion, and the rear seat surface portion. Be done,
At the horizontal fulcrum, which is a rotation fulcrum that is directly or indirectly connected to the pedestal and has an axial structure with a long axis in the left-right direction, which is located behind the front three-fifths of the left and right seats. The left and right seats can be tilted back and forth, respectively.
As an interlocking device connected to the left and right seat surfaces, it is equipped with a gear type reversing device that combines multiple gears including the left and right gears.
In the gear type reversing device, the horizontal support shafts, which are the axes of the left and right gears, extend to the left and right and are fixed to the left and right seat surfaces, and the left and right horizontal support shafts are fixed to the left and right seat surfaces, respectively. A gear-type reversing device is fixed directly or indirectly to the base between the two.
When one of the left and right seats tilts forward due to the leg movement of the seated person seated on the left and right seats to extend one lower limb , the left and right lateral shafts are fixed to the seats. When one of them rotates, the other of the left and right horizontal support shafts is inverted and fixed to the horizontal support shaft via a gear centered on the horizontal support shaft and a gear combined with this gear. chair the other seat part is in effect that tilts rearward, the seat surface portion of the left and right, characterized in that that can be tilted back and forth alternately in conjunction. The interlocking device is a gear type reversing device in which four bevel gears including the left and right bevel gears are combined at positions where their respective axes are orthogonal to each other.
In the gear type reversing device, the horizontal support shafts, which are the axes of the left and right bevel gears, extend to the left and right and are fixed to the left and right seat surfaces, and the left and right horizontal supports are fixed to the left and right seat surfaces, respectively. A gear-type reversing device is fixed directly or indirectly to the base between the shafts.
When one of the left and right seats tilts forward due to the leg movement of the seated person seated on the left and right seats to extend one lower limb , the left and right lateral shafts are fixed to the seats. When one of them rotates, the bevel gear about the horizontal support shaft and the bevel gear about the other of the left and right horizontal support shafts are reversed via the bevel gear whose axis is orthogonal to this bead gear. However, according to claim 1, the other seat surface portion fixed to the horizontal support shaft tilts backward, so that the left and right seat surface portions can be interlocked and alternately tilted back and forth. Chair.

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