A method for producing a seat core material that has a foamed molded substrate and a frame member embedded in a periphery thereof, which includes, as step (a), heating thermoplastic resin expanded beads in a mold cavity, in which the frame member has been disposed, to fusion-bond the expanded beads to each other and to obtain the foamed molded substrate with the frame member being embedded in the periphery thereof; and, as step (b), simultaneously with step (a) or after step (a), forming a void cavity S, S in the foamed molded substrate at a position along and adjacent to the frame member. The void cavity S, S has a size and shape that allows a relative displacement between the frame member and the foamed molded substrate when the foamed molded substrate shrinks after step (b).

A method for producing a seat core material that has a foamed molded substrate and a frame member embedded in a periphery thereof, which includes, as step (a), heating thermoplastic resin expanded beads in a mold cavity, in which the frame member has been disposed, to fusion-bond the expanded beads to each other and to obtain the foamed molded substrate with the frame member being embedded in the periphery thereof; and, as step (b), simultaneously with step (a) or after step (a), forming a void cavity S, S in the foamed molded substrate at a position along and adjacent to the frame member. The void cavity S, S has a size and shape that allows a relative displacement between the frame member and the foamed molded substrate when the foamed molded substrate shrinks after step (b).

A chair is provided in which a seat-receiving member is provided with outward flanges for regulating upward/downward displacement to support left and right lateral edges of a seat plate. Engaging grooves supported by the outward flanges are provided at the respective left and right lateral edges of the seat plate. Warpage allowable parts in which warpage deformation of the lateral edges is allowed without the upward displacement being regulated by the seat receiving member are provided in regions of the left and right lateral edges of the seat plate, in which the regions are located at a rear side from engagement parts between the engaging grooves and the outward flanges. With this constitution, it is possible to prevent the seat plate from being detached from the seat-receiving member while ensuring that, when an user is seated, the sides of the buttocks of the user are reliably held, and thus improve the seating stability of a seat body.

The present invention provides a soft polyurethane foam that is obtained by foam molding a foaming stock solution containing a polyol, diphenylmethane diisocyanate, a foaming agent, and a catalyst. The polyol includes a polyether polyol A having a weight average molecular weight (Mw) of 3,000 to 8,000 and 3 to 4 functional groups. The diphenylmethane diisocyanate (MDI) includes monomeric MDI in an amount of 80 mass % or more with respect to the total mass of the MDL The monomeric MDI includes 4,4-MDI in an amount of 70 mass % or less with respect to the total mass of the MDI.

The present invention provides a soft polyurethane foam that is obtained by foam molding a foaming stock solution containing a polyol, diphenylmethane diisocyanate, a foaming agent, and a catalyst. The polyol includes a polyether polyol A having a weight average molecular weight (Mw) of 3,000 to 8,000 and 3 to 4 functional groups. The diphenylmethane diisocyanate (MDI) includes monomeric MDI in an amount of 80 mass % or more with respect to the total mass of the MDL The monomeric MDI includes 4,4-MDI in an amount of 70 mass % or less with respect to the total mass of the MDI.

Apparatus, systems, and methods are disclosed involving a seat cushion configured as a partially-open annular ring, including a circular hollow space in a center of the ring, and a radial-arc-shaped opening in the ring forming a trapezium-shaped hollow space. The cushion includes a top section, a middle section, and a base section, in which the top and middle sections form the partially-open annular ring. Both the circular hollow space and the trapezium-shaped hollow space are located corresponding to the user's spine and coccyx, with the trapezium-shaped hollow space located on a rear portion of the cushion. The circular hollow space frees the perineal region from external compression by avoiding having any portion of the center of the seat cushion pressing against it, and the trapezium-shaped hollow space frees the sacrococcygeal region from external compression by not having any portion of partially-open annular ring of the seat cushion pressing against it.

Apparatus, systems, and methods are disclosed involving a seat cushion configured as a partially-open annular ring, including a circular hollow space in a center of the ring, and a radial-arc-shaped opening in the ring forming a trapezium-shaped hollow space. The cushion includes a top section, a middle section, and a base section, in which the top and middle sections form the partially-open annular ring. Both the circular hollow space and the trapezium-shaped hollow space are located corresponding to the user's spine and coccyx, with the trapezium-shaped hollow space located on a rear portion of the cushion. The circular hollow space frees the perineal region from external compression by avoiding having any portion of the center of the seat cushion pressing against it, and the trapezium-shaped hollow space frees the sacrococcygeal region from external compression by not having any portion of partially-open annular ring of the seat cushion pressing against it.

A seat pad (1) includes a surface portion (1a) configured of a polyurethane foam (11). In the surface portion (1a), wiring grooves (2) for wiring a wire harness (3) are formed. Each wiring groove (2) has a groove width W narrower than the diameter (? 3) of the harness (3), and a groove depth (D) deeper than the diameter ?3 of the harness (3). A seat pad manufacturing method uses, as a molding die, a molding die that has groove-forming protrusions to form the wiring grooves (2) and has holes formed in side surfaces of the groove-forming protrusions. A polyurethane foam material is supplied to an interior of the molding die, and when a molded product is removed from the molding die, molded portions formed in the holes are forcibly pulled out of the holes of the groove-forming protrusions.

A component for a vehicle seat assembly, a seat assembly, and a method of forming a seat assembly are provided. A unitary foam cushion has a first side, and a second side opposite to the first side to support an occupant. A former extends outwardly from the second side of the foam cushion to a distal end spaced apart from the foam cushion. The former cooperates with the second side of the foam cushion to define an open channel. The open channel is sized to receive a seam of a trim cover assembly. The former defines a first side wall of the open channel, and the second side of the foam cushion defines a second side wall of the open channel. The first side wall defined by the former faces away from the second side of the foam cushion.

A component for a vehicle seat assembly, a seat assembly, and a method of forming a seat assembly are provided. A unitary foam cushion has a first side, and a second side opposite to the first side to support an occupant. A former extends outwardly from the second side of the foam cushion to a distal end spaced apart from the foam cushion. The former cooperates with the second side of the foam cushion to define an open channel. The open channel is sized to receive a seam of a trim cover assembly. The former defines a first side wall of the open channel, and the second side of the foam cushion defines a second side wall of the open channel. The first side wall defined by the former faces away from the second side of the foam cushion.