System And Method Of Forming Variable Density Seating Materials

Abstract

A system and method of forming seating materials having variable density gradient for high hardness ratio of high-to-low deflection, and more specifically to forming foam materials for vehicle seats having variable density gradient that allow greater comfort across a wider range of occupant weights.

In the claims: 
     
         1 . A method of forming a seat cushion comprising:
 providing an uncured foam material;   providing a mold having at least two mold members which cooperate to form a mold cavity and wherein one of said at least two mold members includes at least one moveable member capable of extending from a retracted position to and extended position within said mold cavity and wherein said moveable member decreases the volume of said mold cavity in said extended position;   inserting said uncured foam material within said mold cavity;   allowing said uncured foam material to partially cure to an intermediate state;   moving said at least one moveable member to said extended position and wherein in said extended position a mold surface of said moveable member engages said uncured foam material in said intermediate state;   allowing said uncured foam material in said intermediate state to cure to a final state; and   removing the seat cushion formed from said foam material in a final state.   
     
     
         2 . The method of  claim 1  wherein said step of moving said at least one moveable member includes the step of creating a density gradient in said uncured foam in said intermediate state. 
     
     
         3 . The method of  claim 1  wherein said step of providing an uncured foam material further includes the steps of inserting said uncured foam material into a portion of the mold cavity defined by one of said mold members and closing the mold halves to create said mold cavity including said uncured foam material. 
     
     
         4 . The method of  claim 3  wherein said step of inserting said uncured foam material into a portion of the mold cavity further includes the step of inserting the providing a substantially homogenous foam material. 
     
     
         5 . The method of  claim 1  wherein at least one of said mold members does not include a moveable member and wherein said step of inserting said uncured foam material further includes the step of inserting the uncured foam material into said mold member without said moveable member. 
     
     
         6 . The method of  claim 1  wherein said moveable member in said retracted position does not engage said uncured foam material. 
     
     
         7 . The method of  claim 1  wherein said step of allowing said uncured foam material to partially cure to an intermediate state further includes the step of applying heat for a specified amount of time. 
     
     
         8 . The method of  claim 1  wherein said step of allowing said uncured foam material to partially cure further includes the step of allowing said uncured foam material to expand to at least contact said moveable member in said intermediate state and wherein said uncured foam material when initially placed in said mold member does not touch said moveable member. 
     
     
         9 . The method of  claim 1  wherein said step of moving said at least one moveable further includes the step of creating a density gradient in said foam material. 
     
     
         10 . The method of  claim 1  wherein said step of allowing said uncured foam material in said intermediate state to cure to a final state further includes the step of maintaining said moveable member in said extended state. 
     
     
         11 . The method of  claim 1  wherein said step of allowing said uncured foam material in said intermediate state to cure to a final state further includes the step of retracting said moveable member to a position between said extended state and said retracted state. 
     
     
         12 . The method of  claim 1  wherein said step of allowing said uncured foam to partially cure includes the step of allowing said uncured foam to substantially fill said mold cavity. 
     
     
         13 . The method of  claim 12  wherein said step of moving said at least one moveable member to said extended position and wherein in said extended position a mold surface of said moveable member engages said uncured foam material in said intermediate state, includes the step of reducing the volume of said mold cavity as said at least one moveable member moves to said extended position and wherein the seat cushion has a volume substantially equal to the reduced volume mold cavity. 
     
     
         14 . A seat cushion comprising:
 a foam material having an outer surface include a first surface and an opposing second surface and wherein said foam has a variable density gradient between said first surface and said second surface and wherein said foam material has a density that is greater at said second surface than at said first surface and wherein said seat cushion is formed by a process comprising:   providing an uncured foam material;   providing a mold having at least two mold members which cooperate to form a mold cavity and wherein one of said at least two mold members includes at least one moveable member capable of extending from a retracted position to and extended position within said mold cavity and wherein said moveable member decreases the volume of said mold cavity in said extended position;   inserting said uncured foam material within said mold cavity;   allowing said uncured foam material to partially cure to an intermediate state;   moving said at least one moveable member to said extended position and wherein in said extended position a mold surface of said moveable member engages said uncured foam material in said intermediate state;   allowing said uncured foam material in said intermediate state to cure to a final state; and   removing the seat cushion formed from said foam material in a final state.   
     
     
         15 . The seat cushion of  claim 12  wherein said density gradient varies exponentially between said first surface and said second surface.