Abstract: A quick-assembly structure includes an inserting portion and an inserting port allowing the inserting portion to be inserted, where one of the inserting portion and the inserting port is provided on the chassis, and the other one is provided on the back frame. A locking block of the inserting portion is movably arranged relative to the inserting port; and in an assembled state, a bump of the inserting portion is inserted into the inserting port along with the inserting portion, the locking block is pushed by an elastic force of an elastic member of the inserting port to enter a locking position, and at the locking position, a locking end of the locking block enters the inserting port and abuts against an abutting surface of the bump so as to restrict the inserting portion from being pulled out in a direction opposite to an inserting direction thereof.

Abstract: A quick-assembly structure includes first inserting connection structures, where each of the first inserting connection structures includes an inserting and clamping member and a groove body; each of the groove bodies includes an inserting groove and a clamping groove which are in communication with each other, the corresponding inserting and clamping member is inserted into the inserting groove in a vertical direction and then horizontally slides into the clamping groove in a first direction; and the seat cushion is further provided with elastic buckles, the chassis includes a clamping connection surface, and when the inserting and clamping members slide to predetermined positions in the clamping grooves, the elastic buckles are clamped with the clamping connection surface of the chassis in an abutting manner so as to restrict the chassis from sliding relative to the seat cushion in a direction opposite to the first direction.

Abstract: An armrest installation structure, includes a back frame, a pre-embedded sleeve, and an armrest body. The pre-embedded sleeve is fixedly installed in an inner cavity of the back frame; a side wall of the pre-embedded sleeve is provided with several deadbolt grooves provided along a length direction of the pre-embedded sleeve; the armrest body is internally provided with a deadbolt switchable between an unlocked state and a locked state, and a transmission assembly driving the deadbolt to switch between the two states; in the unlocked state, the deadbolt is stored into the armrest body and comes out of the deadbolt groove, and in the locked state, the deadbolt at least partially extends out of the armrest body and is plugged into any of the deadbolt grooves; and when the deadbolt is inserted into the deadbolt groove, the armrest body and the back frame keep relatively fixed.