Patent ID: 8113582

Claim:
A cushion having a jacket of cushioning material surround a cushion body, the cushion being for a chair, the cushion comprising: the cushion body comprising an elastic sheet plate having a mediate position provided with a convex waist support portion, said cushion body being independent of the chair, said convex waist support portion having a first thickness, an upper end provided with an inclined backrest support portion located above the waist support portion, said inclined backrest support portion having a second thickness, and, a lower end provided with a concave resting portion located under the waist support portion, said concave resting portion having a third thickness, wherein the first thickness of the convex waist support portion is greater than that of the second thickness of the inclined backrest support portion and that of the third thickness of the concave resting portion, wherein the cushion body has a surface provided with a plurality of vertical elongate slots in the waist support portion, wherein the cushion body has a surface provided with a plurality of vertical elongate slots in the backrest support portion, and wherein the vertical elongate slots on the backrest support portion of the cushion body are separated from the vertical elongate slots on the waist support portion of the cushion body by a laterally extending region of the cushion body that is devoid of slots, wherein the laterally extending region extends in a plane completely across the elastic sheet plate at a location between the first thickness and the second thickness so that the backrest support portion and the waist support portion are deformed in response to a seating posture of a user.