Chair and seat-back unit therefor

A chair construction, comprising:

• a unitary seat-back combination unit for supporting a sitter, said unit being somewhat elastically flexible;
• a chair frame of tubular members, adapted to be supported on a surface and having a pair of spaced upper rear support points and a pair of spaced front support points;
• a generally vertical slot in the frame at each of the upper rear support points and a hooked flange extending back from the upper end of the seat-back unit at each side of the unit, engaged in the corresponding slots, the hooked flanges curving upwardly and each including a stop abutment at its lower side for engaging against the tubular member just below the slot when the hooked flange has been inserted in the slot, thereby preventing further downward rotation of the hooked flange and the top of the seat-back unit, with the hooked flanges so oriented on the seat-back unit that the front end of the seat-back unit must be forced downwardly to reach the front support points of the frame;
• and
• means detachably connecting the front end of the seat-back unit to the front support points in said downwardly forced configuration;
• whereby the seat-back unit is flexed and prestressed when the front end of the seat-back unit is connected to the front support points, producing a tight, rattle-free assembly.

A chair comprising:

• a seat-back unit including:
• a parallel pair of relatively rigid but springingly flexible side frame members of generally L-shape, each with a generally horizontal base portion arched upwardly and a generally vertical upright portion arched forwardly, the upright and base portions meeting at a cusped corner;
• a single rigid spacer bridging between the undersides of the base portions adjacent to and forward of said corners, said spacer being the only rigid member bridging said unit;
• and
• springable user support means extending laterally across said side frame members, to provide a back assembly bridging said upright portions and a seat assembly bridging said base portions, the left and right ends of the user support means in each assembly being secured to the side frame members;
• and
• a frame including four legs, the legs being secured to the L-shaped side frame members only at the top of the back assembly and the front of the seat assembly.

A chair, comprising:

• a chair frame adapted to be supported on a surface and including a pair of spaced upper rear support points and a pair of spaced front support points, with means providing for shifting flexibility of the spacing between the support points with the weight of a sitter in the chair,
• a seat-back unit supported on the frame, the seat-back unit having two relatively rigid frame pieces, one at the left edge and one at the right edge, the frame pieces being elastically deformable under the weight of a sitter in the chair,
• stretcher means extending between the two frame pieces, spaced well away from the upper edge and the forward edge of the seat-back unit, for holding the frame pieces in spaced relationship, being the only structure holding the frame pieces apart so that the frame pieces are relatively shiftable and flexible with respect to one another, first connecting means connecting the upper ends of the frame pieces to the upper rear support points,
• second connecting means connecting the front ends of the frame pieces to the front support points, so that the seat-back unit is connected to the chair frame at only four support points, and
• support means comprising two series of sinuous spring wires attached to and extending laterally between the frame pieces, touching each other at series of points and each united by an integral plastic coating surrounding the wires to provide a back assembly and a seat assembly, the sinuous spring wires being arched upwardly in the seat assembly, the spring wires and the arching being cooperative with the flexibility of the frame pieces and the relative flexibility and shiftability between them to provide a high degree of accommodation and comfort for different users.