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

Abstract

A seat device capable of retaining a person's seated position is provided as seats for vehicles, for example. The seat device has an upper body support member having an upper body support surface that supports an upper body back of a person seated. The upper body support surface has slant ridges for ribs. The slant ridges can touch the ribs of the person from beneath and are slanted according to the ribs, the ribs descending with person's exhalation.

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 seated,   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.   
     
     
         2 . The seat device of  claim 1 , 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. 
     
     
         3 . The device of  claim 1 , comprising a seat member having a seat surface on which the person is seated. 
     
     
         4 . The seat device of  claim 3 , 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 3 , 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. 
     
     
         6 . The seat device of  claim 1 , wherein the 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 to the seat surface, 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. 
     
     
         7 . The seat device of  claim 6 , 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. 
     
     
         8 . The seat device of  claim 3 , 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 slant ridges for the ribs. 
     
     
         9 . 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   wherein the upper body support members comprises upper and lower support members so as to provide mutually separated upper and lower support surfaces respectively, the lower support members being fixed to the seat member and having the lower support surface on which the support projections are formed, the upper support member being movable in a vertical direction of the device and having the upper support surface on which the slant ridges are formed.   
     
     
         10 . The seat device of  claim 8 , wherein the upper body support member 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 to the seat surface, 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, and
 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 including the slant ridges for the ribs and the aid ridges for the shoulder blades.   
     
     
         11 . The seat device of  claim 9 , wherein the upper support member 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 to the seat surface, 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. 
     
     
         12 . The seat device of  claim 11 , wherein the upper 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. 
     
     
         13 . 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 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 an upper part of the upper body support member is movable to the seat surface in the vertical direction, the upper part including at least the pair of slant ridges.   
     
     
         14 . The seat device of  claim 13 , 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 pair of support projections being located lower than the pair of slant ridges, and
 the upper body support members comprises upper and lower support members so as to provide mutually separated upper and lower support surfaces respectively, the lower support members being fixed to the seat member and having the lower support surface on which the support projections are formed, the upper support member being movable in a vertical direction of the device and having the upper support surface on which the pair of slant ridges are formed.   
     
     
         15 . The seat device of  claim 13 , wherein the upper body support surface has a pair of first substantially horizontal ridges which are located, ridge by ridge, on both sides of a center line of the upper body support surface in a width direction of the device, the first substantially horizontal ridges being located over the pair of slant ridges in the vertical direction, and
 the upper body support member is configured such that an upper part of the upper body support member is movable to the seat surface in the vertical direction, the upper part including at least the pair of slant ridges and the pair of first substantially horizontal ridges.   
     
     
         16 . The seat device of  claim 14 , wherein the upper support member has a pair of first substantially horizontal ridges which are located, ridge by ridge, on both sides of a center line of the upper body support surface in a width direction of the device, the first substantially horizontal ridges being located over the pair of slant ridges in the vertical direction. 
     
     
         17 . The seat device of  claim 15 , wherein the upper support member has a pair of second substantially horizontal ridges which are located, ridge by ridge, on both sides of the center line of the upper body support surface in the width direction, the second substantially horizontal ridges being located under the pair of slant ridges in the vertical direction. 
     
     
         18 . 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 seated,
 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.   
     
     
         19 . The device of  claim 18 , 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. 
     
     
         20 . The device of  claim 19 , comprising a seat surface on which the person is seated.
 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.