Patent ID: 8371645

Claim:
A mechanism for self folding up and cushioning a seat of a portable chair, comprising: a tension spring having a first hook element and a second hook element, wherein the first hook element includes a first extension, the first extension is parallel to a spring axis and extended from an edge of coils of the tension spring, a distal end of the first extension is extended to form a curved first hook, the second hook element includes a second extension, the second extension is extended from an edge of the coils in a direction perpendicular to the spring axis, a distal end of the second extension is extended toward one side of the coils of the tension spring to overlap a portion of the coils and form a second hook perpendicular to the second extension, the tension spring is assembled in a space between a mount bracket of the seat and a restricting flange provided on a rear leg of the portable chair, a length of the tension spring is substantially equal to a length of a space in which the tension spring is assembled; and a cushioning pad including a retainer portion, an insert portion and a cushion portion, wherein the retainer portion has an opened side for engagement with the rear leg, the cushion portion has a hollow member disposed by the retainer portion, the retainer portion is wrapped around a frame edge of the rear leg, the insert portion is inserted into a groove of the rear leg, whereby a frame of the seat is able to collide against the cushion portion when the seat is folded up by the tension spring so that noise and vibration are reduced.