Seat device having a function of retaining person's seated position

Abstract

A seat device has an upper body support member having an upper body support surface that supports an upper back of a person. The support surface has aid ridges for shoulder blades. The aid ridges are located to be fit to a range of fifth to seventh ribs of the ribs in a vertical direction of the seat member, and are substantially horizontal in a width direction of the seat device. The support surface is located such that a length from a center line of the support surface in a width direction thereof to a center-line-side end of each of the aid ridges is equal to or larger than a length from a backbone center line to a backbone end of the person and equal to or smaller than a length from the backbone center line to a shoulder blade of the person.

What is claimed is: 
     
         1 . A seat device capable of retaining a person's seated position, comprising:
 an upper body support member having an upper body support surface that supports an upper body back of a person to be seated on the seat device,   wherein the upper body support surface has aid ridges for shoulder blades, the aid ridges i) being located to be fit to a range of fifth to seventh ribs of the ribs in a vertical direction of the seat member, ii) being substantially horizontal in a width direction of the seat device, and iii) being located such that a length from a center line of the upper body support surface in a width direction thereof to a center-line-side end of each of the aid ridges is equal to or larger than a length from a backbone center line to a backbone end of the person and equal to or smaller than a length from the backbone center line to a shoulder blade of the person.   
     
     
         2 . The seat device of  claim 1 , comprising a seat member having a seat surface on which the person is seated. 
     
     
         3 . The seat device of  claim 1 , wherein the upper body support surface has horizontal ridges for lower ribs, the horizontal ridges i) being located to be fit to a range of tenth to twelfth ribs of the ribs in the vertical direction and ii) being substantially horizontal to the seat surface. 
     
     
         4 . The seat device of  claim 2 , wherein the upper body support surface has a pair of support projections for ilia, which are fit to a pair of ilium projections of the person, the ilium projections being projected rearward when the person is seated on the seat surface of the seat member, and
 the seat surface has a pair of accommodating recesses for ischiums, which accommodates therein a pair of ischium projected portions of the person, the ischium projected portions being projected downward.   
     
     
         5 . The seat device of  claim 1 , wherein the upper body support surface has slant ridges for ribs, the slant ridges touching the ribs of the person from beneath and being slanted according to the ribs, the ribs descending with person's exhalation. 
     
     
         6 . The seat device of  claim 5 , wherein the slant ridges are formed to touch a person's upper body back between a ninth rib and a tenth rib of the ribs. 
     
     
         7 . The seat device of  claim 2 , wherein the seat surface has a pair of reference ridges each of which is fit to a recess between a biceps femoris muscle and a semimembranosus muscle of each of thighs of the person. 
     
     
         8 . The seat device of  claim 2 , wherein the upper body support member is configured such that at least an upper part of the upper body support member is movable to the seat surface in the vertical direction, the upper part being higher than lower ends of the aid ridges for the shoulder blades. 
     
     
         9 . The seat device of  claim 8 , wherein the upper body support surface has horizontal ridges for lower ribs, the horizontal ridges i) being located to be fit to a range of tenth to twelfth ribs of the ribs in the vertical direction and ii) being substantially horizontal to the seat surface, and
 the upper body support member is configured such that at least an upper part of the upper body support member is movable to the seat surface in the vertical direction, the upper part being higher than lower ends of the horizontal ridges for the lower ribs.   
     
     
         10 . The device of  claim 8 , wherein the upper body support surface has slant ridges for ribs, the slant ridges touching the ribs of the person from beneath and being slanted according to the ribs, the ribs descending with person's exhalation, and the upper body support member is configured such that at least an upper part of the upper body support member is movable to the seat surface in the vertical direction, the upper part being higher than lower ends of the slant ridges for the ribs. 
     
     
         11 . The seat device of  claim 10 , wherein the upper body support surface has horizontal ridges for lower ribs, the horizontal ridges i) being located to be fit to a range of tenth to twelfth ribs of the ribs in the vertical direction and ii) being substantially horizontal to the seat surface, and
 the upper body support member is configured such that at least an upper part of the upper body support member is movable to the seat surface in the vertical direction, the upper part being higher than lower ends of the horizontal ridges for the lower ribs.   
     
     
         12 . A seat device capable of retaining a person's seated position, comprising:
 a seat member having a seat surface on which a person is seated; and   an upper body support member having an upper body support surface that supports an upper body back of the person,   wherein the upper body support surface has a pair of substantially horizontal ridges which are located on both sides of a center line of the upper body support surface in a width direction thereof, and   the upper body support member is configured such that at least an upper part of the upper body support member is movable to the seat surface in the vertical direction, the upper part being higher than lower ends of the pair of substantially horizontal ridges.   
     
     
         13 . The seat device of  claim 12 , wherein the upper body support surface has a pair of slant ridges which are slanted at an angle substantially equal to an inclination angle of the ninth or tenth rib of the person, the slant ridges being located on both sides of a center line of the upper body support surface in a width direction thereof and being slanted as advancing from the center line, and
 the upper body support member is configured such that at least an upper part of the upper body support member is movable to the seat surface in the vertical direction, the upper part being higher than either lower ends of the pair of substantially horizontal ridges or lower ends of the pair of slant ridges.   
     
     
         14 . The seat device of  claim 13 , wherein the pair of substantially horizontal ridges is a pair of substantially horizontal ridges located lower than the pair of slant ridges. 
     
     
         15 . The seat device of  claim 8 , wherein the upper body support surface has a pair of support projections for ilia, which are fit to a pair of ilium projections of the person,
 the seat surface has a pair of accommodating recesses for ischiums, which accommodates therein a pair of ischium projected portions of ischia of the person, and   the upper body support member has a portion in which the pair of support projections for the ilia are provided on the upper body support surface, the portion of the upper body support member being inseparable from the seat member providing the seat surface.   
     
     
         16 . A device capable of retaining a person's seated position, comprising:
 an upper body support surface that supports an upper body back of a person to be seated,   wherein the upper body support surface has aid ridges for shoulder blades, the aid ridges i) being located to be fit to a range of fifth to seventh ribs of the ribs in a vertical direction of the device, ii) being substantially horizontal in a width direction of the device, and iii) being located such that a length from a center line of the upper body support surface in a width direction thereof to a center-line-side end of each of the aid ridges is equal to or larger than a length from a backbone center line to a backbone end of the person and equal to or smaller than a length from the backbone center line to a shoulder blade of the person.   
     
     
         17 . The device of  claim 16 , comprising a seat surface on which the person is seated,
 wherein the upper body support surface has horizontal ridges for lower ribs, the horizontal ridges i) being located to be fit to a range of tenth to twelfth ribs of the ribs in the vertical direction and ii) being substantially horizontal to the seat surface.   
     
     
         18 . The device of  claim 17 , wherein the upper body support surface has a pair of support projections for ilia, which are fit to a pair of ilium projections of the person, the ilium projections being projected rearward when the person is seated on the seat surface, and
 the seat surface has a pair of accommodating recesses for ischiums, which accommodates therein a pair of ischium projected portions of the person, the ischium projected portions being projected downward.   
     
     
         19 . The seat device of  claim 16 , wherein the upper body support surface has slant ridges for ribs, the slant ridges touching the ribs of the person from beneath and being slanted according to the ribs, the ribs descending with person's exhalation. 
     
     
         20 . The seat device of  claim 19 , wherein the slant ridges are formed to touch a person's upper body back between a ninth rib and a tenth rib of the ribs.