Flip-up seat construction

A flip-up seat construction comprising:

• at least one seat pan having a bottom portion, a seat-back portion separate from the bottom portion, and a frame unit which includes a seat-back assembly for supporting the seat-back portion and a bottom assembly for supporting the bottom portion, said bottom assembly being swingably attached to the seat-back assembly and swingable between a horizontal seat position and a stand-up position;
• said seat-back assembly of said frame unit having:
• a seat-back portion/first horizontal cross member which extends horizontally at a position corresponding to an upper end of said seat-back portion of said seat pan;
• a seat-back portion/second horizontal cross member which extends horizontally at a position corresponding to a lower end of said seat-back portion of said seat pan;
• a seat-back portion/first side member which is connected between respective ends at a first side of said seat-back portion/first and second horizontal cross members;
• a seat-back portion/second side member which is connected between respective ends at a second side of said seat-back portion/first and second horizontal cross members;
• and
• a swingably supporting member which is integrally constructed with said seat-back portion/first and second side members and swingably supports said bottom assembly of said frame unit, and
• said bottom assembly of said frame unit having:
• a bottom portion/first horizontal cross member which extends horizontally at a position corresponding to a back end of said bottom portion near the lower end of said seat-back portion when said bottom portion is in a horizontal seat position;
• a bottom portion/second horizontal cross member which extends horizontally at a position corresponding to a front end of said bottom portion away from the lower end of said seat-back portion when said bottom portion is in a horizontal seat position;
• a bottom portion/first side member which is connected between respective ends at a first side of said bottom portion/first and second horizontal cross members;
• and
• a bottom portion/second side member which is connected between respective ends at a second side of said bottom portion/first and second horizontal cross members;
• wherein said bottom assembly has a center of swing located in the swingably supporting member below and in front of the lower end of said seat-back portion,
• wherein said seat-back assembly further comprises a seat-back portion/additional horizontal cross member which horizontally extends at a position lower than and in front of the center of swing of said bottom assembly,
• wherein said swingably supporting member having first and second side connection members which are fixed to said seat-back portion/first and second side members and which extend downward to both ends of said additional horizontal cross member,
• wherein said swingably supporting member of said seat-back assembly is mounted on said first and second side connection members,
• wherein a rear end portion of said bottom assembly located near the center of swing contacts lower ends of said seat-back portion/first and second side members of said seat-back assembly when said bottom portion of said seat pan is at the horizontal seat position and thereby prohibits the swing movement of said bottom assembly from the seat position in a direction opposite to the stand-up position, and
• a swing prohibiting means mounted on said additional horizontal member for prohibiting swing movement of said bottom assembly when said bottom assembly is in the stand-up position.