Spring Tension Sofa Bed Folding Conversion Mechanism

✅ Thickened High-Speed Punching Steel Frame Whole bracket made of thick cold-rolled steel via integrated high-speed punching molding. Reinforced multi-link triangular folding structure, anti-bending and anti-deformation, stable bearing without shaking after long-term frequent folding. ✅ Labor-Saving Tension Spring Reset System Equipped with high-tensile stainless steel extension spring, provides auxiliary pulling force during folding & unfolding. Smooth switching between sofa and bed mode, no heavy pushing or pulling required; the spring automatically locks the position after conversion. ✅ Four-Step Simple Conversion Operation Clear 4-stage folding logic: raise cushion → lift frame → flatten support → reset to bed surface. Easy operation for all ages, no extra tools needed, greatly improves user experience of multi-functional sofas.   ✅ Anti-Rust Matte Black Spraying Treatment Uniform matte black electrostatic powder coating fully covers all metal surfaces, wat…