Seat cushion

Claim 2

In a portable auxiliary seat cushion having a seat panel and a back rest panel hingedly connected by a hinge connection to form a unitary structure and wherein the under side of said seat panel and the rearward side of said back rest panel have a high coefficient of friction to prevent relative slippage between said seat cushion and any supporting surfaces on which it is placed; the improvement which comprises, in combination; said under side of said seat panel and said rearward side of said back panel being composed of a flexible, resilient synthetic plastic foam having a high coefficient of friction; and stitch means for preventing said back panel from falling forward onto said seat panel, said stitch means extending across said hinge connection and being anchored in said seat panel and back rest panel, thereby maintaining said back panel in a generally upright position when said seat cushion is placed on a structure providing support for said seat panel and back rest panel.

Claim 3

The seat cushion of claim 1 wherein said stitch means operates to prevent said back rest panel from falling forward onto said seat panel but does not prevent folding the underside of said seat panel against the rearward side of said back rest panel to form a compact folded seat cushion for storage in the minimum volume of space.

Claim 4

The seat cushion of claim 1 wherein the stitch means comprises at least two laterally spaced lines of stitching extending across the hinged connection and a substantial distance into said seat panel and back rest panel on each side of said hinged connection.

Claim 5

The seat cushion of claims 1, 2 or 3 wherein said stitching is made with an elastic material.

Claim 6

A portable, auxiliary seat cushion having a seat panel and a back rest panel hingedly connected by a hinge connection to form a unitary structure, the under side of said seat panel and rearward side of said back rest panel have a high coefficient of friction to prevent relative slippage between said seat cushion and any supporting surfaces on which it is placed, comprising: said seat panel and said back panel including a layer of a flexible, resilient foam material; and stitch means compressing said layer of foam material along said hinge connection of said panels thereby biasing said panels relative to one another such that said back panel resists forward pivoting toward said seat panel when said seat cushion is placed on a seat structure having a seat portion and back rest portion disposed generally transversely in an upright position.

Claim 7

A portable, auxiliary seat cushion having a seat panel and a back rest panel hingedly connected by a hinge connection to form a unitary structure, the under side of said seat panel and rearward side of said back rest panel have a high coefficient of friction to prevent relative slippage between said seat cushion and any supporting surfaces on which it is placed, comprising: said seat panel and said back panel including a layer of a flexible, resilient foam material; and stitch means compressing said layer of foam material along said hinge connection of said panels thereby biasing said panels relative to one another such that said back panel resists forward pivoting toward said seat panel when said seat cushion is placed on a seat structure having a seat portion and back rest portion disposed generally transversely in an upright position.

Claim 8

A seat cushion of claim 5, further comprising a first sheet overlying one side of said foam layer and forming the top surface of said seat panel and back rest panel and a second sheet underlying the opposite face of said foam layer forming the underside of said seat panel and rearward side of said back rest panel, said stitch means connecting said first and second sheets to said foam layer along said hinge connection.

Claim 9

A seat cushion as claimed in claim 6, wherein said first sheet comprises a fibrous material.

Claim 10

A seat cushion as claimed in claim 6, wherein said second sheet comprises a flexible resilient material.

Claim 11

A seat cushion as claimed in claim 6, wherein said stitch means also connects said first and second sheets along the periphery of said seat cushion providing additional biasing to maintain said seat cushion in said generally upright position.

Claim 12

A seat cushion as claimed in claim 5, further comprising sheet material completely encapsulating said foam layer and connected thereto by said stitch means at least along said hinge connection.

Claim 13

In a portable, auxiliary seat cushion having a seat panel and a back rest panel hingedly connected by a hinge connection to form a unitary structure, the under side of said seat panel and the rearward side of said back rest panel have a high coefficient of friction to prevent relative slippage between said seat cushion and any supporting surfaces on which it is placed comprising: said seat panel and said back rest panel including a layer of a flexible, resilient foam material; a flexible resilient sheet surrounding said layer of said seat panel and said back rest panel forming the underside of said seat panel and rearward side of said back rest panel; and stitch means holding gathered portions of said sheet thereby providing tension between said underside of said seat panel and rearward side of said back rest panel along said hinged connection, such that said back panel is maintained in a generally upright position when said seat cushion is placed on a seat structure having a seat portion and back rest portion disposed generally transversely in an upright position.

Claim 14

In a portable, auxiliary seat cushion having a seat panel and a back rest panel hingedly connected by a hinge connection to form a unitary structure, the under side of said seat panel and the rearward side of said back rest panel have a high coefficient of friction to prevent relative slippage between said seat cushion and any supporting surfaces on which it is placed comprising: said seat panel and said back rest panel including a layer of a flexible, resilient foam material; a flexible resilient sheet surrounding said layer of said seat panel and said back rest panel forming the underside of said seat panel and rearward side of said back rest panel; and stitch means holding gathered portions of said sheet thereby providing tension between said underside of said seat panel and rearward side of said back rest panel along said hinged connection, such that said back panel is maintained in a generally upright position when said seat cushion is placed on a seat structure having a seat portion and back rest portion disposed generally transversely in an upright position.

Claim 15

The seat cushion of claim 11, wherein said stitch means holds said gathered portions in the form of a welt.

Claim 16

The seat cushion of claim 12, wherein said welt is held by said stitch means along said hinged connection.

Claim 17

A portable, auxiliary seat cushion having a seat panel and a back rest panel hingedly connected by a hinged connection to form a unitary structure, comprising: said seat panel and said back panel including a layer of a flexible, resilient foam material; and stitch means compressing said layer of foam material along said hinge connection of said panels thereby biasing said panels relative to one another such that said back panel resists forward pivoting toward said seat panel when said seat cushion is placed on a seat structure having a seat portion and back rest portion disposed generally transversely in an upright position.

Claim 18

A portable, auxiliary seat cushion having a seat panel and a back rest panel hingedly connected by a hinged connection to form a unitary structure, comprising: said seat panel and said back panel including a layer of a flexible, resilient foam material; and stitch means compressing said layer of foam material along said hinge connection of said panels thereby biasing said panels relative to one another such that said back panel resists forward pivoting toward said seat panel when said seat cushion is placed on a seat structure having a seat portion and back rest portion disposed generally transversely in an upright position.