The present invention discloses a structure for rapidly assembling a chair back and a chair seat. It comprises a chair seat underframe having a first engaging portion and an assembling channel and a chair back stand having a second engaging portion and an assembling block for correspondingly engaging with the assembling channel. The assembling channel has two protrusions at two lateral walls and the assembling block has two engaging grooves at two laterals for positioning and engaging with the two protrusions. The assembling channel of the chair seat underframe has an engaging hole, and a telescopic pin disposed at a bottom of the assembling block is positioned and engaged with the engaging hole. The assembling channel of the chair seat underframe and the assembling block of the chair back stand are further screwed together by a screwing member.

A hidden joining system with front activation for a bottom of a piece of furniture and furnishing items includes a front joining unit and a rear joining unit positioned between a bottom and a shoulder of the furniture, wherein each front and rear joining unit is attached beneath the thickness of the bottom of the furniture, wherein symmetry axes of the two front and rear joining units lie on a plane external and parallel to a center plane of the bottom and the front joining unit has a transmission element toward the rear joining unit.

A hidden joining system with front activation for a bottom of a piece of furniture and furnishing items includes a front joining unit and a rear joining unit positioned between a bottom and a shoulder of the furniture, wherein each front and rear joining unit is attached beneath the thickness of the bottom of the furniture, wherein symmetry axes of the two front and rear joining units lie on a plane external and parallel to a center plane of the bottom and the front joining unit has a transmission element toward the rear joining unit.