Cushion and method of evaluating the cushion

Abstract

There is provided a floor-cushion whose structure is such that it (a) enables a person sitting on it to maintain his/her backbone in an appropriate posture, while (b) causing little fatigue in the sitter's muscles, even during long-time sitting. The inside of said floor-cushion ( 1 ) is divided into a buttocks-supporting portion ( 1 A) and a legs-crossed portion ( 1 B). The buttocks-supporting portion is filled with cork chips ( 2 ), while in the legs-crossed portion a hard-foam resin layer ( 3 ) is enwrapped by two soft-foam resin layers ( 4 ), so that the legs-crossed portion has a three-layer structure. The buttocks-supporting portion is made thicker than the legs-crossed portion, so that the buttocks-supporting portion inclines downward toward the legs-crossed portion, so as to promote forward inclination of the pelvis.

1 . A floor-cushion, covered with a floor-cushion bag, wherein: 
 said floor-cushion is divided into a buttocks-supporting portion and a legs-crossed portion,    the buttocks-supporting portion is filled with cork chips,    the legs-crossed portion contains a hard-foam resin layer that is enwrapped by two soft-foam resin layers, thus making a three-layer structure for the legs-crossed portion, and    the buttocks-supporting portion is thicker than the legs-crossed portion and inclines downward toward the legs-crossed portion so as to promote forward inclination of a sitter's pelvis.    
     
     
         2 . The floor-cushion as set forth in  claim 1 , wherein said hard-foam resin layer is a plate-like, hard-polyurethane layer, and said surrounding soft-foam resin layer is a soft-polyester foam layer.  
     
     
         3 . The floor-cushion as set forth in  claim 1 , wherein the forward-inclination angle of the top of said buttocks-supporting portion is 5 degrees to 30 degrees on average.  
     
     
         4 . The floor-cushion as set forth in  claim 1 , wherein said cork chips occupy 20% to 25% of the space of the buttocks-supporting portion.  
     
     
         5 . The floor-cushion as set forth in  claim 1 , wherein the shape of said floor-cushion is basically heart-like, with the narrower, rear area of the “heart” being the thick, buttocks-supporting portion, while the wider, front area of the “heart” is the legs-crossed portion, and with the area occupied by a floor-cushion intended for females being larger than that of a floor cushion intended for males.  
     
     
         6 . The method of evaluating a floor-cushion described in  claim 1 , wherein said method uses the results of: 
 a short-time sitting simulation, that includes    measurements of a sitter's pelvic-inclination angle,    videotape recording of said sitting, and    the sitter's evaluation of his/her sensory experience of sitting comfort;    a long-time sitting simulation that includes    measurement of variations in a sitter's pelvic-inclination angle,    videotape recording of said sitting,    frequency analysis of said pelvic-inclination angles, and    the sitter's evaluation of his/her sensory experience of a feeling of fatigue at preselected parts of the sitter's body; and    information obtained via questionnaires concerning said floor cushion, completed by various people, including Europeans and Americans.    
     
     
         7 . The method of evaluating a floor-cushion as set forth in  claim 6 , wherein said pelvic-inclination angles are measured by having each of a predetermined number of test subjects wear a pelvic-inclination-angle sensor belt, whereby each person's pelvic-inclination angle is measured while the person is sitting on a commercially available floor-cushion and while he/she is sitting on the floor-cushion of this invention, with said angle.  
     
     
         8 . The method of evaluating a floor-cushion as set forth in  claim 6 , wherein after said sensory-experience evaluations of sitting comfort is completed there is created a radar chart that shows extracted factors obtained by processing the collected data regarding assessment items—using the analysis of variance method—so that the subjective assessments made by the test subjects in said sensory-experience evaluations can be utilized.  
     
     
         9 . The method of evaluating a floor-cushion as set forth in  claim 6 , wherein said variations in a sitter's pelvic-inclination angle in said long-time sitting is measured three times, i.e., at the start of sitting, 20 minutes after the start of sitting, and 40 minutes after the start of sitting, for the aforementioned predetermined parts of the sitter's body.  
     
     
         10 . The method of evaluating a floor-cushion as set forth in  claim 6 , wherein said frequency analysis of the pelvic-inclination angle is done using a time-series-analysis model formula.  
     
     
         11 . The floor-cushion as set forth in  claim 1 , wherein the forward-inclination angle of the top of said buttocks-supporting portion is 5 degrees to 30 degrees on average.