Method and apparatus for bonding a sheet for a corrugated cardboard box

An apparatus for bonding a sheet for a corrugated cardboard box comprising:

• an upper transporting means and a lower transporting means for vertically dividing one set of two sheets for the corrugated cardboard box, respectively, in which a connecting flap projects on one side with a first folding line taken as a boundary and a connected flap corresponding to the connecting flap is formed on a rear surface of the other side, a second folding line being formed between the connecting flap and the connected flap, a connecting-flap side sheet and a connected-flap side sheet being provided between the first folding line and the second folding line and between the second folding line and the connected flap, respectively, and transporting the thus divided sheets in a horizontal direction,
• an upper position-control means and a lower position-control means provided at the respective positions at least scheduled to be folded, respectively in the one set of two sheets for the corrugated cardboard box;
• an assembly which comprises an upper connecting-flap folding means for folding the connecting flap and an upper connected-flap side sheet folding means for folding the connected-flap side sheet with the respective first and second folding lines in each of the both sheets for the corrugated cardboard box taken as boundaries;
• another assembly which comprises a lower connecting-flap folding means for folding the connecting flap and a lower connected-flap side sheet folding means for folding the connected-flap side sheet provided on a diagonal line and symmetric with respect to the above-mentioned assembly;
• an upper intermittent moving means for intermittently moving the both sheets for the corrugated cardboard box provided on a diagonal line and symmetric with respect to the upper intermittent moving means;
• a lower intermittent moving means for intermittently moving the both sheets for the corrugated cardboard box provided on a diagonal line and symmetric with respect to the upper intermittent moving means;
• an upper sewing machine which comprises a sewing-machine needle mechanism provided with a horizontally movable sewing-machine needle and a looper mechanism having a needle plate;
• a lower sewing machine which comprises a sewing-machine needle mechanism provided with a horizontally movable sewing-machine needle and a looper mechanism having a needle plate and is provided on a diagonal line and symmetric with respect to the upper sewing machine;
• the needle plate of each of the looper mechanisms being provided inside the connecting flap scheduled to be thread-stitched and each of the sewing-machine needle mechanisms being arranged outside the connected flap scheduled to be thread-stitched;
• and
• synchronizing the sewing-machine needle with the intermittent movement of the intermittent moving means to reciprocally move it in a horizontal direction from the outside of the connected flap to the inside connecting flap so as to stitch the threading portion, which comprises the connecting flap and the connected flap, with threads.