Pivotal seat for a collapsible playpen

A pivotal seat for a collapsible playpen comprising:

• a pivotal seat at a lower center of a collapsible playpen, said pivotal seat having four inverse U-shaped branches projected outward from four lateral sides respectively each including a first aligned thru hole in a pair of lateral walls thereof wherein two of said branches are parallel to each other each having a check surface on top of an outer end and an arcuate surface beneath said check surface for pivoting one end of a pair of elastic rods and the other two branches are perpendicular to said above branches for pivoting one end of a pair of conventional rods, the other end of said rods being pivoted to four lower corner members of said playpen respectively, said pivotal seat further including a foot projected downward from a bottom, a central bore in a top thereof above said foot, a first knot on an inner wall of said central bore, a pair of first vertical holes symmetrically formed in upper rims of said central bore, a pair of moving spaces symmetrically formed on upper rims of said central bore abutting said vertical holes and a pair of first slots symmetrically formed on upper rims of said central bore abutting said moving spaces respectively;
• an inverse T-shaped member disposed into the central bore of said pivotal seat, a pair of rotors superimposedly wrapped on said inverse T-shaped member biased by a pair of coil springs on top and bottom thereof, a cover covering on said rotors and said coil springs and a semi-circular handle engaged with said cover;
• whereby, by rotating said handle clockwise and simultaneously lift up said pivotal seat, the playpen is collapsible.