JP2019037272A - Posture holder - Google Patents

Abstract

To hold an upper half of the body of a seated person in a right posture.SOLUTION: A posture holder 10 includes: a seat part 11; a backrest part 16 rising from the rear end part of the seat part 11; a first support part 17 constituting the backrest part 16, with which a central part in the lateral direction of the back 52 of the seated person 50 is brought into contact; and a pair of second support parts 18 disposed on both of the right and left sides of the first support part 17 constituting the backrest part 16, with which both of the right and left sides of the back 52 of the seated person 50 are brought into contact. The lowermost end part 17L in the upper edge part of the first support part 17 is disposed at a position lower than the uppermost end part 18U in the upper edge part of the second support parts 18.SELECTED DRAWING: Figure 11

Description

  The present invention relates to a posture holder.

  Patent Document 1 discloses a posture holder that holds a seated person in a correct state. The posture holder includes a buttock support portion that supports the buttock of the seated person from below, and a waist support portion that rises from the rear edge of the buttock support portion. The waist support portion has a height capable of supporting the seated person's waist and the lower end of the back, and has a substantially square plate shape as a whole.

JP 2014-12130 A

  In the above posture holder, the front surface of the waist support part (the surface where the waist and the back hit) is generally flat, so that the seated person can tilt the upper body to the left or right or twist the upper body to the left or right. Easy to do. However, this posture retainer cannot stabilize the upper body of the seated person in the correct posture, so that the seated person spends a long time with the upper body tilted left and right or the upper body twisted left and right. There is a concern that

  The present invention has been completed based on the above circumstances, and an object thereof is to hold the upper body of a seated person in a correct posture.

The posture holder of the present invention is
A seat,
A backrest in the form of rising from the rear end of the seat;
A first support part that constitutes the backrest part and abuts the center part in the left-right direction of the back of the seated person;
The backrest part comprises a pair of second support parts that are arranged on the left and right sides of the first support part and contact the left and right sides of the back of the seated person,
The lowermost end portion of the upper edge portion of the first support portion is disposed at a position lower than the uppermost end portion of the upper edge portion of the second support portion.

  The seated person sits in a state where a relatively low part in the center part of the back is applied to the first support part and a relatively high part in the left and right side parts of the back is applied to the second support part. Since the posture holder of the present invention supports the seated person's back with three support parts, the seated person's upper body is restrained from being tilted left and right or twisted right and left, and the seated person's upper body is correct. It can be held in a posture.

The perspective view of the attitude | position holder of Example 1 Front view of posture holder Top view of posture holder AA line sectional view in which the exterior sheet of FIG. 2 is omitted. BB line sectional view in which the exterior sheet of FIG. 2 is omitted CC sectional view in which the exterior sheet in FIG. 2 is omitted. DD cross-sectional view with the exterior sheet of FIG. 2 omitted EE line sectional view which omitted the exterior sheet of FIG. FF line sectional view which omitted the exterior sheet of FIG. GG sectional drawing which omitted the exterior sheet of FIG. HH line sectional view in which the exterior sheet of FIG. 3 is omitted A cross-sectional view corresponding to the line AA in FIG. 2 showing the use state of the posture holder.

In the present invention, the upper end portion of the second support portion may be curved so as to warp obliquely rearward as it goes upward.
According to this configuration, there is no possibility that the upper end edge of the second support part bites into the body of the seated person when the upper body of the seated person is put on the backrest part.

In the present invention, the seat portion constituting plate portion constituting the seat portion and the back portion constituting plate portion constituting the backrest portion are elastically displaced relative to each other with the lower end portion of the backrest portion constituting plate portion as a substantial fulcrum. The backrest portion constituting plate portion is configured so that the back support portion constituting plate portion protrudes obliquely forward from the first support plate portion constituting the first support portion and the left and right side edges of the first support plate portion. The protrusion dimension from the said 1st support plate part in the lower end side area | region of the said 2nd support plate part may become small gradually toward the downward direction.
According to this configuration, when the seated person presses the upper body against the backrest portion, the backrest portion is elastically displaced backward with the lower end edge as a substantial fulcrum. Since the protrusion dimension from the 1st support plate part in the lower end side area | region of a 2nd support plate part becomes small gradually toward the downward direction, the lower end side area | region of a backrest part structural plate part is also elastically deformed. Thereby, stress concentration to the lower end edge of the backrest component plate portion can be prevented.

In the present invention, a first support surface facing the back of the first support portion and a second support surface facing the back of the second support portion are connected via a pair of left and right connecting surfaces. In a plan view, the curvature of the first support surface and the curvature of the second support surface may be smaller than the curvature of the joint surface.
According to this configuration, since the back does not hit the connecting surface having a large curvature, the upper body of the seated person can be stably supported at the three positions of the first support surface and the pair of left and right second support surfaces. .

<Example 1>
A first embodiment of the present invention will be described below with reference to FIGS. In the following description, in the front-rear direction, the left side in FIGS. 4 to 6 and 12 and the lower side in FIGS. For the up and down directions, the directions appearing in FIGS. 1, 2, 4 to 6, 11, and 12 are defined as “upper” and “lower” as they are. For the left and right directions, the directions appearing in FIGS. 2, 3, and 7 to 11 are defined as left and right as they are.

  The posture holder 10 according to the first embodiment is structurally and functionally composed of a seat portion 11 that supports the buttocks 51 of the seated person 50 from below, and a backrest portion 16 that supports the back 52 of the seated person 50 from behind. Constructed and symmetrical. The seat portion 11 and the backrest portion 16 are integrated. In the first embodiment, the “back 52 of the seated person 50” is defined as the back and waist of the seated person 50 (the back side and the side of the trunk of the upper body).

  The planar view shape of the seat part 11 is demonstrated. As shown in FIG. 3, in the front-rear direction, the rear end side support region 12 </ b> R extending from the rear end of the seat 11 to the front approximately 2/3 has a substantially trapezoidal shape that is gradually widened toward the front. In the rear end side support region 12R, the width dimension (the dimension in the left-right direction) of the seat portion 11 is maximized. The outer peripheral edge of the front end side support region 12F ahead of the rear end side support region 12R in the seat portion 11 is composed of a pair of left and right symmetrical front curved edges 13 and a front edge punching portion 14. The front curved edge portion 13 is connected to the left and right side edges of the rear end side support region 12R and constitutes the front edge portion of the seat portion 11. The front edge curling portion 14 has a shape recessed in an obtuse angle at the center portion in the left-right direction of the seat portion 11, and connects the left and right front curved edges 13.

  The front view shape of the seat part 11 is demonstrated. As shown in FIGS. 2 and 11, the seat portion 11 includes a pair of left and right symmetrical support portions 15 that are curved so that the upper surface side is recessed. Since the seat part 11 is high in the center part in the left-right direction and the left and right end parts, it can stably support the buttock part 51 and the base part of the thigh of the seated person 50.

  As shown in FIGS. 1 and 4, the backrest 16 is a form that rises upward from the rear end of the seat 11. The backrest portion 16 includes a first support portion 17 that constitutes a central portion in the left-right direction of the backrest portion 16 and a pair of symmetrical second support portions 18 that constitute left and right side edges of the backrest portion 16. Has been. The left and right second support portions 18 are in a cantilevered form extending obliquely forward from the left and right side edges of the first support portion 17. The extending direction of the left and right second support portions 18 is such that the distance between the left and right directions of the second support portions 18 gradually increases toward the front in plan view.

  The front surface of the backrest 16 is a support surface 19 that contacts or faces the back 52 of the seated person 50. The front view shape of the support surface 19 (backrest part 16) is demonstrated. As shown in FIGS. 2 and 11, in the vertical direction (height direction), the lower end side support region 20 extending from the lower end of the backrest portion 16 to approximately 2/3 above forms a substantially trapezoid gradually widening upward. . The outer peripheral edge of the upper end side support region 21 above the lower end side support region 20 in the backrest portion 16 is composed of a pair of left and right upper curved edge portions 22 and an upper edge turn portion 23. The upper curved edge portion 22 is connected to the left and right side edges of the lower end side support region 20 and constitutes the upper edge portion of the backrest portion 16. The upper turning portion has a shape recessed in an obtuse angle at the central portion in the left-right direction of the backrest portion 16, and connects the left and right upper curved edges 22.

  The upper curved edge portion 22 is formed only on the outer peripheral edge of the second support portion 18. The upper edge punching portion 23 constitutes the entire upper edge portion of the first support portion 17 and a part of the upper edge portion of the second support portion 18. The height dimension of the upper edge portion of the backrest portion 16 is the maximum at the upper end of the upper curved edge portion 22 and is the minimum at the lowermost end (the center in the left-right direction of the backrest portion 16) of the upper edge bend portion 23. In other words, the lowermost end portion 17L at the upper edge portion of the first support portion 17 is disposed at a position lower than the uppermost end portion 18U at the upper edge portion of the second support portion 18. The lowermost end portion 17L at the upper edge portion of the first support portion 17 is at a position higher than the lower end (the height at which the backrest portion 16 has the maximum width) of the upper curved edge portion 22 (upper end support region 21). The lower end of the upper curved edge 22 has a height at which the backrest 16 has the maximum width.

  As shown in FIG. 2, the width dimension of the backrest portion 16 is maximum at the upper end of the lower end side support region 20 (lower end of the upper curved edge portion 22). The maximum width dimension of the backrest part 16 is set slightly smaller than the maximum width dimension of the seat part 11. The width dimension of the backrest portion 16 is the smallest at the lower end portion 16L (that is, the rear end portion of the seat portion 11) of the backrest portion 16 (lower end side support region 20). The interval (width dimension) between the upper ends of the left and right upper curved edges 22 is smaller than the maximum width dimension of the backrest 16. The height dimension of the backrest part 16 is set larger than the front-rear dimension of the seat part 11.

  As shown in FIGS. 2 and 3, the support surface 19 includes a first support surface 24 that constitutes the first support portion 17 and a pair of symmetrical second support surfaces 28 that constitute the second support portion 18. Has been. The first support surface 24 is disposed at the center in the left-right direction of the support surface 19 and forms a vertically long substantially square as a whole. As shown in FIG. 4, the upper end portion of the first support surface 24 is a first upper curved surface 25 that bulges diagonally upward and forward and curves so as to warp diagonally upward and backward.

  As shown in FIG. 4, the lower end portion 24L of the first support surface 24 is smoothly connected to the rear end portion of the seat portion 11 that is curved so as to be inclined upward. A region below the first upper curved surface 25 in the first support surface 24 is a first receiving surface 27 that is substantially planar. The first receiving surface 27 is generally oriented along the vertical direction when the posture holder 10 is used. The vertical dimension of the first receiving surface 27 is approximately ½ of the total height of the first support surface 24.

  The pair of left and right second support surfaces 28 are disposed on the left and right sides of the first support surface 24 of the support surface 19. The second support surface 28 has a shape extending obliquely forward from the left and right side edges of the first support surface 24. The front edge portion of the second support surface 28 has a curved shape so as to swell forward. That is, the dimension in the front-rear direction of the second support surface 28 (the dimension extending from the side edge of the first support surface 24) becomes larger in the upper end side support region 21 of the second support surface 28 as it goes upward. The lower support area 20 of the second support surface 28 becomes smaller as it goes downward.

  A region close to the first support surface 24 in the left-right direction in the second support surface 28 is a second receiving surface 29. The second receiving surface 29 has a substantially planar shape substantially parallel to the extending direction of the second support portion 18. A peripheral portion of the second support surface 28 that surrounds the second receiving surface 29 from above, forward, and below is curved so as to swell obliquely inward and warp obliquely backward.

  The upper end portion of the second support surface 28 is a second upper curved surface 30 that is curved so as to swell diagonally upward and forward and warp diagonally upward and backward. The left and right second upper curved surfaces 30 are smoothly connected to the left and right sides of the first upper curved surface 25. The lower end portion of the second support surface 28 is a second lower curved surface 31 that is curved so as to swell obliquely downward and forward.

  As shown in FIGS. 3 and 11, in plan view, the left and right side edges of the first support surface 24 and the second receiving surface 29 of the second support surface 28 of the support surface 19 are connected to a pair of left and right regions. The connecting surface 32 is recessed in an arc shape. The pair of connecting surfaces 32 are bilaterally symmetric and extend elongated in the vertical direction. In plan view, the curvature of the first support surface 24 (first receiving surface 27) and the curvature of the second support surface 28 (second receiving surface 29) are small values close to zero, whereas the connecting surface 32 The curvature is large. A substantially trapezoidal holding space 33 opened forward is configured by the first support surface 24, the left and right second support surfaces 28, and the left and right connecting surfaces 32 in front of the backrest portion 16. Has been.

  The 1st receiving surface 27 of the 1st support part 17 is an area | region which the center part of the left-right direction of the back 52 of the seated person 50 can hit at the time of seating among the 1st support surfaces 24. The 2nd receiving surface 29 of the 2nd support part 18 is an area | region which the right and left both sides of the seated person's 50 back 52 can contact at the time of sitting among the 2nd support surfaces 28. FIG. The uppermost position of the first receiving surface 27 is set to a position lower than the uppermost position of the second receiving surface 29. The first receiving surface 27 is positioned so as to be sandwiched between the pair of second receiving surfaces 29 in the left-right direction. Therefore, the posture holder 10 can support the back 52 of the seated person 50 at three locations by the one first receiving surface 27 and the pair of left and right second receiving surfaces 29. The three receiving surfaces 27 and 29 have a height difference, and are in a positional relationship with a space left and right and a space before and after.

  As shown in FIG. 12, the posture holder 10 includes an outer shell member 34, a cushion material 39, and an exterior sheet 40 in terms of component configuration. The outer shell member 34 is a single member made of a hard synthetic resin and having a plate shape with a constant thickness over the entire region. The outer shell member 34 is formed in a curved shape so that the shape in side view is generally L-shaped. The outer shell member 34 includes a seat portion constituting plate portion 35 constituting the seat portion 11 and a backrest portion constituting plate portion 36 constituting the backrest portion 16. The seat part constituting plate part 35 has a shape substantially the same as the shape of the seat part 11 described above, and is constituted by a plurality of curved plate parts curved so as to have different curvatures. The backrest component plate portion 36 is configured to rise upward from the rear end portion of the seat component plate portion 35, and includes a first support plate portion 37 and a second support portion 18 that constitute the first support portion 17. It is composed of a pair of symmetrical second support plate portions 38 to be configured.

  The shape of the first support plate portion 37 is substantially the same shape as the first support portion 17 and the first support surface 24 described above. The height region corresponding to the first receiving surface 27 of the first support plate portion 37 is a curved shape so that the shape of the side view swells forward as a whole, and the posture holder 10 is placed on a horizontal plane. The direction is slightly inclined forward from the vertical direction. Moreover, the area | region corresponding to the 1st upper curved surface 25 among the 1st support plate parts 37 is curving so that it may warp diagonally up back. A region of the first support plate portion 37 corresponding to the first lower bending portion 26 has a curved shape so as to be inclined downward and to swell obliquely downward and rearward.

  The pair of second support plate portions 38 extends in a cantilever manner so that the left and right side edges of the first support plate portion 37 form a substantially straight line obliquely forward and the distance between the left and right sides expands forward. It is. The shape of the second support plate portion 38 is substantially the same shape as the second support portion 18 and the second support surface 28 described above. A region of the second support plate portion 38 corresponding to the second receiving surface 29 has a substantially flat plate shape, and a peripheral portion of the second support plate portion 38 is curved so as to bend obliquely rearward.

  As shown in FIG. 4, the lower end portion 36 </ b> L of the backrest portion constituting plate portion 36 is connected to the rear end portion of the seat portion constituting plate portion 35, but constitutes the lower end portion 36 </ b> L of the backrest portion constituting plate portion 36. Only the first support plate portion 37 does. That is, the first support plate portion 37 is directly connected to the seat portion constituting plate portion 35, but the second support plate portion 38 is directly connected to the seat portion constituting plate portion 35. Instead, the first support plate portion 37 is connected to the seat portion constituting plate portion 35.

  The outer shell member 34 maintains the overall shape of the posture holder 10, and has rigidity (shape retention) that can stably hold the posture of the seated person 50. However, when a static load caused by the weight of the seated person 50, a dynamic load caused by a change in the sitting posture of the seated person 50, or the like is received, it may be elastically deformed to such an extent that the seated attitude is not affected. It has become. Specifically, the second support plate portion 38 is elastically displaced relative to the first support plate portion 37 so that the left and right side edges of the first support plate portion 37 are expanded in the left-right direction with the fulcrum as a fulcrum. It has come to be able to do.

  When the static load or the dynamic load is applied, the backrest component plate portion 36 (backrest portion 16) is supported by the backrest component plate portion 35 (seat portion 11). The lower end portion 36L (the rear end portion of the seat portion constituting plate portion 35) of the portion 36 can be elastically relatively displaced so as to tilt the posture in the front-rear direction. At this time, the amount of elastic deformation of the backrest component plate portion 36 (stress generated in the backrest component plate portion 36) becomes maximum at the lower end portion 36L, which is a substantially fulcrum of elastic displacement, but the first support plate portion 37. At least the lower end side support region 20 is also elastically deformed. The elastic deformation of the lower support region 20 of the first support plate 37 is preferable as a means for avoiding stress concentration at the lower end 36L of the backrest component plate 36.

  However, the second support plate portions 38 protruding from the left and right side edges of the first support plate portion 37 function as reinforcing ribs that resist elastic deformation of the first support plate portion 37. Therefore, as shown in FIGS. 8 to 10, the projecting dimension from the first support plate portion 37 in the lower end side region of the second support plate portion 38 is set so as to gradually decrease downward. As a result, when the backrest component plate 36 is elastically displaced in the front-rear direction with respect to the seat component plate 35, the lower end side region of the first support plate 37 is also elastically curved and deformed. Yes. In the first embodiment, the lower end side region of the second support plate portion 38 is defined as a region extending from the lower end portion 38L of the second support plate portion 38 to a height of at least about 1/3.

  The cushion material 39 is attached so as to be laminated on the surface of the outer shell member 34 facing the seated person 50 (the upper surface of the portion constituting the seat portion 11 and the front surface of the portion constituting the backrest portion 16). Yes. The cushion material 39 is made of urethane foam, for example, and is a member for avoiding discomfort caused by the buttocks 51 and the back 52 of the seated person 50 hitting the hard outer shell member 34. The thickness of the portion of the cushion material 39 corresponding to the first receiving surface 27 does not have a constant dimension in the vertical direction, but the thickness dimension changes so as to gradually increase in thickness downward. Thereby, when the attitude holder 10 is placed on a horizontal plane, the first receiving surface 27 of the first support surface 24 is in a direction to rise substantially vertically.

  The exterior sheet 40 is made of cloth, and faces the seated person 50 among the outer surface of the outer shell member 34 (the lower surface of the portion constituting the seat portion 11 and the rear surface of the portion constituting the backrest portion 16) and the cushion material 39. The entire surface (the upper surface of the portion constituting the seat portion 11 and the front surface of the portion constituting the backrest portion 16) is covered. When the outer shell member 34 is elastically deformed, the cushion material 39 and the exterior sheet 40 follow and flexibly deform.

  The posture holder 10 can be used in a state where it is placed directly on the floor (not shown) or on a chair 53. FIG. 12 shows a state where it is used on a chair. When the seated person 50 sits on the posture holder 10, the buttocks 51 are supported from below by the seat 11, the upper body trunk is accommodated in the holding space 33, and the back 52 is supported from behind by the backrest 16. At this time, a portion corresponding to the lower thoracic vertebra of the center portion in the left-right direction of the back 52 contacts the first support surface 24, and both left and right portions of the back 52 contact the left and right second support surfaces 28.

  At this time, the contact portion with the second support surface 28 is a position higher than the contact portion with the first support surface 24 and is a position in front of the contact portion with the first support surface 24. . That is, the back 52 can support a plurality of parts having different positions in the three-dimensional direction. In addition, when the seated person 50 is an average body type adult, the contact position with the second support surface 28 is on the back side of the rib and is lower than the scapula.

  The posture holder 10 according to the first embodiment has a seat portion 11 that supports the buttocks 51 of the seated person 50 from below, and a form that stands up from the rear end of the seated portion 11, and the upper body of the seated person 50 from the back 52 side. And a supporting backrest portion 16. The backrest part 16 is disposed on the left and right sides of the first support part 17 so as to contact the center part in the left-right direction of the back 52 of the seated person 50, and on both left and right sides of the back 52 of the seated person 50. And a pair of second support portions 18 with which the portions abut.

  The first support part 17 supports a relatively low part in the center part of the back 52 of the seated person 50 from behind, and the pair of left and right second support parts 18 is higher than the first support part 17 in the left and right side parts of the back 52. Support the part so that it is sandwiched from behind. Therefore, the seated person 50 sits in a state where a relatively low portion in the center portion of the back 52 is applied to the first support portion 17 and a relatively high portion in the left and right side portions of the back 52 is applied to the second support portion 18. . Since the seated person 50 is spaced apart from each other by the three support portions 17 and 18 and can support the back 52 at three places with different heights, the upper body is inclined left and right or the upper body is twisted left and right. To be suppressed. Therefore, the posture holder 10 of the first embodiment can hold the upper body of the seated person 50 in a correct posture.

  Further, the first support portion 17 supports a relatively low portion (the whole or a part of the range from the upper part of the lumbar vertebra to the lower part of the thoracic vertebra) of the back 52 of the seated person 50, and the second support portion 18 compares the back 52. When the seated person 50 deposits his / her weight in the backrest portion 16, the upper part of the rib is supported (all or part of the corresponding part of the back of the rib from the lower part of the thoracic vertebra to the middle height of the thoracic vertebra). The back 52 is supported at a plurality of places with different heights. Thereby, the upper body of the seated person 50 is maintained in a correct posture such that the spine draws an appropriate curve in a side view. Here, the correct posture is a posture in which the thoracic vertebra is curved so as to swell rearward, the lumbar vertebra is curved so as to swell forward, and curved so as to swell rearward from the sacrum to the tailbone.

  In addition, when the height of the upper end of the first support portion 17 is made equal to the height of the upper end of the second support portion 18, the thoracic vertebra portion that is curved so as to bulge backward in the back 52 is the first support portion 17. There is a risk that it will be difficult for the spine to draw an appropriate curve. As a countermeasure, the posture holder 10 according to the first embodiment forms an upper edge rim portion 23 at the upper end edge of the backrest portion 16, and the height of the upper end of the first support portion 17 is set to the upper end of the second support portion 18. Although the lower edge portion 23 is formed, since the space immediately above the first support portion 17 (that is, between the upper ends of the left and right second support portions 18) is formed, the first edge portion 23 is formed. The back 52 cannot be supported immediately above the support portion 17. For this reason, there is a concern that a portion of the upper body of the seated person 50 above the first support portion 17 (a portion where the back 52 is relatively low) warps backward. Since it is supported by the second support portion 18 on both the left and right sides above the first support portion 17, the seated person 50 can be seated in a relaxed state with a moderately open chest.

  Further, in the seated state, the second support portion 18 is elastically displaced obliquely rearward by receiving a pressing force from the upper body of the seated person 50. Therefore, due to the elastic restoring force of the second support portion 18 (second support plate portion 38), The pressure is felt stronger at the left and right sides than at the center of the back 52. Therefore, it can suppress that the upper body of the seated person 50 becomes the attitude | position leaning right and left or the attitude | position twisted right and left.

  In addition, since the second upper curved surface 30 is formed at the upper end portion of the second support portion 18 so as to bend obliquely backward as it goes upward, the upper body of the seated person 50 is placed on the backrest portion 16. The upper edge of the second support part 18 does not bite into the body of the seated person 50 when leaning deeply, and the seated person 50 can sit deeply on the seat part 11. Further, by sitting down deeply, the left and right sides of the back 52 are firmly pressed against the second support 18, so that it is possible to reliably prevent the upper body from being twisted to the left and right. Furthermore, since the upper end portion of the second support portion 18 does not bite into the body of the seated person 50, the upper part of the back 52 can be warped rearward appropriately, so that the seated person 50 can be held in a correct posture. it can.

  The posture holder 10 includes an outer shell member 34 for maintaining the shape of the posture holder 10. The outer shell member 34 includes a seat portion constituting plate portion 35 constituting the seat portion 11 and a backrest portion constituting plate portion 36 constituting the backrest portion 16. The backrest component plate portion 36 is connected to the seat component plate portion 35 so that it can be elastically displaced relative to the lower end portion 36L of the backrest component plate portion 36 as a substantial fulcrum. Therefore, when the seated person 50 strongly presses the upper body against the backrest portion 16, the backrest portion 16 is elastically displaced rearward relative to the seat portion 11 with the lower end portion 36L as a substantial fulcrum.

  At this time, if stress concentrates on the lower end portion 36L of the backrest component plate portion 36, which is a fulcrum of relative elastic displacement, there is a concern that the deterioration progresses due to repeated stress concentration and the durability decreases. . Means for preventing stress from concentrating on the lower end portion 36L of the backrest portion constituting plate portion 36 include not only the lower end portion 36L of the backrest portion constituting plate portion 36 but also at least the lower end side of the backrest portion constituting plate portion 36. It is preferable to elastically deform the region together.

  However, the backrest constituting plate portion 36 constitutes the second support portion 18 by projecting obliquely forward from the first support plate portion 37 constituting the first support portion 17 and the left and right side edges of the first support plate portion 37. Since it consists of a pair of left and right second support plate portions 38, it is difficult to deform. Therefore, the projecting dimension from the first support plate 37 in the lower end side region of the second support plate 38 is gradually decreased downward. Thereby, the backrest part constituting plate part 36 is elastically deformed not only at the lower end part 36L but also at the lower end side region, so that stress can be prevented from concentrating on the lower end part 36L of the backrest part constituting plate part 36. In addition, since the upper end side area | region of the backrest part structure board part 36 has high bending rigidity compared with a lower end side area | region, and is hard to elastically deform, it can hold | maintain the upper body of the seated person 50 stably.

  Further, the first support surface 24 of the first support portion 17 that faces the back 52 and the second support surface 28 of the second support portion 18 that faces the back 52 via the pair of left and right connecting surfaces 32. The curvature of the 1st support surface 24 and the curvature of the 2nd support surface 28 are set smaller than the curvature of the connection surface 32 in planar view. According to this configuration, since the back 52 does not hit the connecting surface 32 having a large curvature, the upper body of the seated person 50 is stabilized at the three positions of the first support surface 24 and the pair of left and right second support surfaces 28. Can be supported.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.
(1) The posture holder of the above-described embodiment is a unit in which the seat portion and the backrest portion are integrally formed, but the posture holder is configured by assembling the seat portion and the backrest portion of separate members. It may be a thing.
(2) In the above embodiment, the upper end portion of the second support portion is curved so as to bend obliquely backward as it goes upward, but the upper end portion of the second support portion is not curved. Also good.
(3) Although the backrest part constituting plate part of the above embodiment is formed by integrally forming the first support plate part and the second support plate part, the backrest part constituting plate part is the first member of the separate member. The first support plate portion and the second support plate portion may be assembled.
(4) In the above embodiment, the projecting dimension from the first support plate portion in the lower end side region of the second support plate portion gradually decreases downward, but in the lower end side region of the second support plate portion. The projecting dimension from the first support plate portion may be substantially constant in the vertical direction.
(5) In the above embodiment, the seat portion and the backrest portion are elastically displaced relatively, but the seat portion and the backrest portion may not be relatively displaced.
(6) In the above-described embodiment, the first support surface and the second support surface are connected via a connecting surface having a large curvature, and the back of the seated person is supported at three points spaced apart from each other, However, the present invention is not limited to this, and the curvature of the connecting surface may be smaller than that of the first embodiment, and the back may be supported in a region continuous in the left-right direction from the left second support surface to the right second support surface. Even in this case, the upper body of the seated person can be prevented from being inclined left and right or twisted left and right.
(7) In the above embodiment, the upper edge rim portion is formed at the upper edge portion of the first support portion so that a space is left in the vicinity of the upper portion of the first support portion (between the upper end portions of the left and right second support portions) However, it is possible to align the height of the upper end of the first support portion and the height of the upper end of the second support portion to substantially the same height without forming the upper edge punching portion. Even if the upper edge of such a backrest has a constant height over a wide range, the degree of backward tilting of the region corresponding to the upper end of the first support portion of the upper edge of the backrest is reduced. If it is deeper than the upper end part of the second support part, when the back is bent backward, it is possible to avoid that the center part in the left-right direction of the back strongly hits the upper edge part of the backrest part.

DESCRIPTION OF SYMBOLS 10 ... Posture holder 11 ... Seat part 16 ... Backrest part 17 ... 1st support part 18 ... 2nd support part 17L ... The lowest end part in the upper edge part of a 1st support part 18U ... Upper edge part of a 2nd support part 24 ... 1st support surface 28 ... 2nd support surface 32 ... Connecting surface 35 ... Seat part component plate part 36 ... Backrest part component plate part 36L ... Lower end part of backrest part component plate part 37 ... First Support plate part 38 ... 2nd support plate part 50 ... Seated person 51 ... Buttocks 52 ... Back

Claims (4)

A seat,
A backrest in the form of rising from the rear end of the seat;
A first support part that constitutes the backrest part and abuts the center part in the left-right direction of the back of the seated person;
The backrest part comprises a pair of second support parts that are arranged on the left and right sides of the first support part and contact the left and right sides of the back of the seated person,
The posture holding tool, wherein the lowermost end portion of the upper edge portion of the first support portion is disposed at a position lower than the uppermost end portion of the upper edge portion of the second support portion.   The posture holding tool according to claim 1, wherein the upper end portion of the second support portion is curved so as to bend obliquely backward as it goes upward. The seat-constituting plate portion constituting the seat portion and the backrest-constituting plate portion constituting the backrest portion can be elastically relatively displaced with the lower end portion of the backrest-constituting plate portion as a substantially fulcrum. In a row
The backrest constituting plate portion includes a first support plate portion constituting the first support portion, and a second support portion projecting obliquely forward from left and right side edges of the first support plate portion. It consists of a support plate part,
The posture holder according to claim 1 or 2, wherein a projecting dimension from the first support plate portion in a lower end side region of the second support plate portion gradually decreases downward. A first support surface facing the back of the first support portion and a second support surface facing the back of the second support portion are connected via a pair of left and right connecting surfaces,
4. The posture holder according to claim 1, wherein the curvature of the first support surface and the curvature of the second support surface are smaller than the curvature of the joint surface in a plan view. 5.

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