Manufacturing fiberboard ducts

An apparatus for fabricating a flat fiberboard duct from a flat fiberboard having a plurality of linear sections comprising two intermediate sections and two outer end sections which terminate laterally with linear edges adapted to be secured together to form a linear seam, the first outer end section having a linear flap adjacent to the first outer end section linear edge and adapted to overlap the linear seam and be secured to the second outer end section adjacent to the second outer end section linear edge to form a fiberboard duct, the apparatus comprising:

• a supporting frame;
• drive conveyor means supported by said frame where said frame is adapted to advance partially collapsed flat folded fiberboard through the apparatus from the rear entrance to the forward exit of the apparatus;
• a linear guide means supported by said supporting frame overhead said drive conveyor at the entrance portion of said apparatus where said linear guide means is adapted to engage and maintain in square alignment the first outer end section linear distal edge and the second outer end section distal edge and to bend said flap upwardly while said conveyor advances the partially collapsed fiberboard forwardly through apparatus, said linear guide means comprising a forwardly disposed linear catilevered member containing a plurality of lower roller means and a plurality of upper roller means, the lower roller means operative to ride on the interior surface of one of the intermediate fiberboard sections and the upper roller means operative to support the fiberboard second outer end section while the partially collapsed fiberboard is passing through the apparatus, whereby said guide means maintains square alignment of the partially collapsed fiberboard;
• flattening means supported by said frame and disposed forwardly of the rear entrance of the apparatus, said flattening means adapted to engage the upwardly directed flap of the advancing partially collapsed fiberboard and flatten the flap onto the second end section of the collapsed fiberboard;
• preheat means supported by said frame and disposed forwardly adjacent to said flattening means for preheating the flap of said partially collapsed fiberboard duct while advancing through the apparatus;
• tape dispensing means supported by said frame adapted to dispense a predetermined length of heat sensitive tape to be applied in a taping area located forward of said preheating means to secure the preheated flap and second outer end section of the partially collapsed fiberboard, whereby the tape secures the linear seam of the partially collapsed fiberboard;
• heating iron means supported by said frame and disposed forwardly of said taping area, said heating iron adapted to heat the tape whereby the heated tape adheres to the flap and the second outer end section of the partially collapsed fiberboard;
• and
• cooling means supported by said frame and disposed forwardly of said heating means, said cooling means adapted to cool the heated tape and secure the linear seam of the partially collapsed fiberboard, whereby the partially collapsed fiberboard can be removed from the exit portion of the apparatus.

In a process for fabricating a fiberboard duct from a fiberboard having a plurality of linear sections comprising two intermediate sections and two outer end sections which terminate laterally with linear edges adapted to be secured together to form a linear seam, the first outer section having a linear flap adjacent to the first outer end section linear edge and adapted to overlap the linear seam and be secured to the second outer end section adjacent to the second outer end section linear edge to form a fiberboard duct, the process steps comprising:

• folding the fiberboard wherein the first outer end section and second outer end section meet to provide a folded fiberboard duct having the distal linear edges of the first and second outer end section form a linear seam;
• advancing the folded fiberboard duct and aligning the linear seam with a centrally disposed downwardly depending linear guide means supported overhead for advancing the folded fiberboard where each distal linear edge of the outer end sections engage the linear guide means to maintain the folded fiberboard in square alignment with the linear guide means;
• partially collapsing the folded fiberboard between converging conveying means to form a partially collapsed fiberboard duct while maintaining the partially collapsed fiberboard duct in alignment with said linear guide means;
• preheating the seam of the partially collapsed fiberboard duct while maintaining alignment with said linear guide means;
• applying heat sensitive tape to the seam of said partially collapsed fiberboard duct while maintaining alignment with said linear guide means;
• heating and pressing the heat sensitive tape to secure the tape whereby the tape secures the fiberboard flap to the second outer end section;
• cooling the heated tape to set the while removing the partially collapsed fiberboard duct.