Apparatus for ultrasonic sealing of non-uniform folded carton bottom

Abstract

Apparatus is disclosed for use with a conventional bottom closure folding machine for ultrasonically sealing folded carton bottom closures having at least two differing thicknesses or laminates comprising, in part, a unique sealing horn and multi-surface mandrel pad arrangement which makes possible the ultrasonic sealing of a laminated bottom closure of varying thicknesses for a container composed of thermoplastic double coated foldable material such as, for example, a polyethylene double coated paperboard carton. The sealing horn comprises a substantially conventional body portion surmounted by a face having a recessed portion and a raised portion for forcibly engaging the folded carton bottom closure and forming an ultrasonic seal at predetermined critical areas of the bottom closure. The multi-surface mandrel pad has a multiplicity of surfaces which lie in at least two distinct planes and which are shaped to receive and engage sections of tabs and panels of the folded carton bottom closure so that when the sealing horn and multisurface mandrel pad are forcibly urged together, the force exerted on the folded carton bottom closure over the area of contact between the face portion of the sealing horn and the surface of the folded carton bottom closure is substantially uniform. The multi-surface mandrel pad, through its multiplicity of surfaces, receives and engages sections of tabs and panels of the infolded surface of the folded carton bottom closure during sealing thereby preventing excessive vibration of those portions of the carton bottom closure which are not in forcible engagement with the raised portion of the sealing horn face during sealing thereby avoiding unwanted 'burn through'.