MEJORAS A METODO Y APARATO PARA EL SELLADO DE CARTONES

摘要

Apparatus for forming a seal between layers of a carton of thermoplastic coated paperboard material and the like wherein the thermoplastic material in the area to be sealed serves as the sealant and is activated to flow by frictional heat generated by a vibration welding horn and is then allowed to cool and set under pressure to form the seal between the layers. The carton first moves to an activating station wherein the layers to be sealed are engaged on opposite surfaces by a vibrating horn and a back-up member (in the form of an anvil or a mandrel) for a time sufficient to activate the thermoplastic material to flow. The carton is then carried to a clamping and sealing station at a different location from the activating station with the thermoplastic material in the activated state. The layers to be sealed with the activated thermoplastic is then engaged on opposite surfaces by a pressure pad and the back-up member for a predetermined period of time to permit the activated thermoplastic to cool and set and form a seal. A holding member extends between the activating and clamping and sealing stations. The holding member overlies the back-up member for engaging the outer surface of the layers to hold the layers together in cooperation with the back-up member when the carton is located at either of the stations or between the stations. The holding member is slotted to permit the horn and pressure pad to engage the outer surface of the layers while the layers are held in the closed position between the holding member and back-up member.