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

Abstract

A device for retaining a person' seated position is provided as seats for vehicles, for example. The device has a seat member and an upper body support member. The seat member a seat surface on which a person is seated. The upper body support member has an upper body support surface that supports an upper body back of the person. 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. 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.

What is claimed is: 
     
         1 . A seat device for retaining a person' 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 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. 
   
     
     
         2 . 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. 
     
     
         3 . The seat device of  claim 2 , 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. 
     
     
         4 . The seat device of  claim 1 , 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. 
     
     
         5 . 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. 
     
     
         6 . The seat device of  claim 5 , 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. 
     
     
         7 . The seat device of  claim 2 , 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. 
     
     
         8 . The seat device of  claim 5 , 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 aid ridges are formed. 
     
     
         9 . The seat device of  claim 7 , 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 a length from than the backbone center line to a shoulder blade of the person. 
     
     
         10 . The seat device of  claim 9 , 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. 
     
     
         11 . The seat device of  claim 1 , 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 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.   
     
     
         12 . The seat device of  claim 1 , 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 of the device, 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 substantially horizontal ridges are formed.   
     
     
         13 . The seat device of  claim 11 , wherein the upper 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 the width direction, the pair of substantially horizontal ridges being located over the pair of slant ridges in the vertical direction. 
     
     
         14 . The seat device of  claim 13 , wherein the upper 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 the width direction, the pair of substantially horizontal ridges being located under in the vertical direction. 
     
     
         15 . A device for retaining a person' seated position, comprising:
 a seat surface on which a person is seated; and   an upper body support surface that supports an upper body back of the person,   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, 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.   
     
     
         16 . The device of  claim 15 , 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. 
     
     
         17 . The device of  claim 16 , 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. 
     
     
         18 . The device of  claim 15 , 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. 
     
     
         19 . The device of  claim 15 , 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 surface, 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. 
     
     
         20 . The device of  claim 19 , 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.