Zero-wall trifold sofa bed

A zero-wall trifold sofa bed, comprising a sofa base, wherein the sofa base is provided with two symmetrical folding assemblies;

• each of the two symmetrical folding assemblies comprises a first long arm and a second long arm, wherein the first long arm and the second long arm are pivoted to a front side of an inner wall of an armrest box of the sofa base;
• the first long arm and the second long arm are jointly pivoted to a first assembly element for assembling a first sofa base;
• a middle part of the first long arm is provided with a first short arm;
• a middle part of the second long arm is provided with a second short arm and a third short arm;
• the first short arm and the second short arm are jointly pivoted to a second assembly element for assembling a second sofa base;
• the third short arm is pivoted to a first end of a connecting rod, and a second end of the connecting rod is pivoted to a first end of a third assembly element for assembling a backrest;
• a second end of the third assembly element is pivoted to a first end of a pull rod, and a second end of the pull rod is pivoted to a back side of the inner wall of the armrest box of the sofa base;
• a side of the third assembly element adjacent to the connecting rod is provided with a roller;
• and the inner wall of the armrest box of the sofa base is provided with a horizontal sliding groove for the roller to slide.