Base and assembly sofa

An assembly sofa, comprising a front frame element, front seat connectors arranged at left and right ends of the front frame element, two side frame elements with a preset interval, side front connectors arranged on the side frame elements and suitable for being connected to the front seat connectors, a backrest, backrest connectors arranged on left and right sides of the backrest, side seat rear connectors arranged on the side frame elements and suitable for being connected to the backrest connectors, a seat board, seat board connectors arranged on left and right sides of the seat board, and side seat middle connectors arranged on the side frame elements and suitable for being connected to the seat board connectors;

• each side front connector is provided with an assembly base surface;
• positioning units are arranged on the assembly base surfaces;
• each front seat connector is provided with an assembly fitting surface making contact with the corresponding assembly base surface;
• positioning cutoffs for limiting final assembly positions of the front seat connectors on the side seat front connectors are arranged on the assembly fitting surfaces;
• and
• first guiding pathways and second guiding pathways for guiding the positioning units to reach the positioning cutoffs in a first assembly direction and a second assembly direction and circuitous pathways for guiding the positioning units to reach the second guiding pathways from the first guiding pathways in a circuitous assembly direction are arranged on the assembly fitting surfaces;
• locking units which have preset shapes and can retract after being extruded are arranged on the assembly base surfaces;
• locking cutoffs which allow the locking units extruded by the assembly fitting surfaces to rebound to the preset shapes at final installation positions and are combined with the locking units are arranged on the assembly fitting surfaces;
• the locking units comprise combinations presented as preset shapes, and extension bodies which extend out of the combinations and penetrate through the side seat front connectors;
• each side seat front connector comprises an assembly bottom surface opposite to the corresponding assembly base surface, and the extension bodies are provided with abutting-against structures capable of making contact with the assembly bottom surfaces, so as to completely show the combinations on the assembly base surfaces;
• supporting base portions are arranged on sides, positioned on the assembly bottom surfaces, of the side seat front connectors, elastic units which are arranged in retraction directions of the locking units and have an elastic compression amount are arranged on the supporting base portions, and the elastic units support the abutting-against structures or the extension bodies to make the abutting-against structures kept in a state of making contact with the assembly bottom surfaces;
• the circuitous pathways are provided with circuitous inflection points, and circuitous pathway front sections and circuitous pathway rear sections are limited by the circuitous inflection points as boundaries;
• the circuitous assembly direction corresponding to the circuitous pathway rear sections is consistent with the second assembly direction;
• and a first assembly path limited by the first guiding pathways and the second guiding pathways and a second assembly path limited by the first guiding pathways, the circuitous pathways and the second guiding pathways coexist side by side.