sofa simple mechanism:Specification: 1. The ottoman adopts the design of wide heavy gauge links and built-in articulating elevated mid-ottoman. Profile shape designed for safety and appearance without pinch points.Articulating designs allows use of wider&higher mid-ottoman for elimination of entrapment areas and for leg support. 2. The system adopts the geometrically engineering theory. The occupant can change from the sitting position to reclining position at any position as he wants to. Occupant is weight is used to balance operation and to make the mechanism extending or retracting to ensure the occupant is safety and comfort. 3. The system uses locking devices on both side brackets. It enables maximum synchronization of side positive locking of both sides. Ottoman is locked closed on both sides 4. The system uses the extended life rivet joints design. All rivet joints have either acetal or bronze rivet bushing and acetal spacers to eliminate any steel to steel contact. No metal to metal noises when links contact nylon stop pins.