Abstract: An armrest structure includes a cover and a controlling member which has a pressing portion and a rack portion respectively formed on two sides thereof. A sliding plate has a sliding protrusion and multiple teeth which are engaged with the rack portion. A fixing plate has a sliding groove and the sliding protrusion is slidably engaged with the sliding groove. A fixing device has a sliding area and two first rails. The sliding plate is engaged with the first rails. The fixing device has a recessed area in which the fixing plate is located. The fixing device has multiple engaging teeth engaged with the rack portion, and two guide grooves. A base is connected with the cover and has two second rails which are engaged with the two guide grooves. A height adjustment device is connected to a slot of the fixing device and fixed to the fixing plate.

Abstract: A portable chair has a mechanism for self folding up and cushioning a seat. The mechanism includes a tension spring assembled between a seat frame and a rear leg for collapsing the seat, and a cushioning pad affixed on the rear leg. The tension spring has first and second hook elements disposed on different orientations and engaged with holes. The hook elements are easy to install, and reduce the risk of disengagement after assembly. The length of the spring is substantially equal to the length of the space in which it is assembled, so that it is not excessively stretched during assembly, thereby preventing spring fatigue. The cushioning pad is integrally formed and includes retainer and insert portions through which it is affixed with the rear leg, and a cushion portion that can absorb noise and vibration when the seat is collapsed.