US Patent 7364229 Automatic ventilation device for chair

An automatic ventilation device for chairs uses a movable plate that moves upwards and downwards along with a cushion. A reset spring is disposed on the movable plate. The upper side and lower side of movable plate each have a stretchable air bag. When the removable plate moves upwards and downwards, one air bag is extended while the other is compressed. The upper and lower air bags have one-way air inlets and outlets respectively while the air outlets are connected to the chair cushion and the chair back for blowing air to the chair cushion and chair back.