Two station sonic sealing apparatus and method

A method of forming a seal between layers of a carton of thermoplastic coated paperboard material and the like wherein the thermoplastic material of the layers in the area to be sealed serves as the sealant and is activated by frictional heat from a vibration welding horn and then allowed to cool and set under pressure to form a seal between the layers, said method comprising:

• locating a vibrating horn having a work surface for engaging one outer surface of the layers at a activating station;
• locating a pressure pad at a clamping and sealing station spaced from the activating station;
• clamping the areas to be sealed between the work surface of the vibrating horn and the work surface of back-up means at the activating station to activate the thermoplastic material of said layers by the heat generated by the vibrating horn;
• unclamping the layers from between the work surfaces of the vibrating horn and back-up means at the activating station after the horn has vibrated a predetermined period of time to activate the thermoplastic material;
• moving the carton with the thermoplastic material in the activated state to the clamping and sealing station;
• clamping the layers to be sealed with the activated thermoplastic material between the work surfaces of the pressure pad and a back-up means located at the clamping and sealing station for a predetermined period of time to permit the thermoplastic material to cool and set and form a seal between the layers.

A method of forming a seal between layers of thermoplastic coated paperboard material and the like, said method comprising the steps of:

• clamping the layers between the opposed work surfaces of a vibrating horn and a back-up means for a predetermined period of time sufficient to cause the thermoplastic material to be thermally activated by the frictional heat generated by the vibrating horn;
• unclamping the layers from between the work surfaces of said horn and back-up means while the thermoplastic material is still in its activated state;
• moving the layers with the activated thermoplastic material to another location;
• and clamping the layers between opposed work surfaces at said another location for a predetermined period of time sufficient to permit the thermoplastic material to cool and set and form a seal between the layers.

A method of forming a seal between layers of an end closure of a carton of thermoplastic coated paperboard material and the like wherein the thermoplastic material of the layers in the area to be sealed serves as the sealant and is activated by frictional heat from a vibration welding horn and then allowed to cool and set under pressure to form a seal between the layers, said method comprising:

• locating a preclosing pad and back-up means at a preclosing station;
• locating a vibrating horn having a work surface for engaging one outer surface of the layers at an activating station;
• locating a clamping and sealing pressure pad at a clamping and sealing station spaced from the activating station;
• closing and pressing the layers of the end closure between the preclosing pad and back-up means at the preclosing station with a pressure sufficient to effect permanent set tending to maintain the end closure in its closed condition;
• clamping the areas to be sealed between the work surface of the vibrating horn and the work surface of back-up means at the activating station to activate the thermoplastic material of said layers by the heat generated by the vibrating horn;
• unclamping the layers from between the work surfaces of the vibrating horn and back-up means at the activating station after the horn has vibrated a predetermined period of time to activate the thermoplastic material;
• moving the carton with the thermoplastic material in the activated state to the clamping and sealing station;
• clamping the layers to be sealed with the activated thermoplastic material between the work surfaces of the pressure pad and a back-up means located at the clamping and sealing station for a predetermined period of time to permit the thermoplastic material to cool and set and form a seal between the layers.

Apparatus for closing and sealing the end closures of a tubular container of thermoplastic coated paperboard material or the like wherein the thermoplastic coating serves as the sealant and is activated by heat from a vibration welding horn and then allowed to cool and set under pressure to form a seal between the layers of the end closures, said apparatus comprising:

• a mandrel for receiving one of the tubular containers with both ends opened at a loading station such that the opened bottom end closure projects from the end of the mandrel;
• a bottom end closure breaker unit operable to fold and close the bottom end closure against the end of the mandrel such that the mandrel defines a back-up means and the end thereof defines a work surface engaging one surface of the bottom end closure;
• a bottom end closure sealant activating station at one location;
• a bottom end closure clamping and sealing station at another location;
• a bottom end closure horn located at said bottom end closure activating station that vibrates at a predetermined frequency when energized;
• said bottom end closure horn having a work surface for engaging the opposite outer surface of the bottom end closure;
• said bottom end closure horn and mandrel being movable with respect to each other at said bottom end closure activating station between a retracted inactive position and an extended active position in which the opposed work surfaces of the horn and mandrel engage the layers of the bottom end closure in a clamping relationship such that vibration of said bottom end closure horn generates frictional heat to activate the thermoplastic material of said bottom end closure layers;
• a bottom end closure pressure pad located at said bottom end closure clamping and sealing station;
• said bottom end closure pressure pad having a work surface for engaging the outer surface of the layers of the bottom end closure in opposed relationship with the work surface of said mandrel at said bottom end closure clamping and sealing station;
• said bottom end closure pressure pad and mandrel being movable with respect to each other at said bottom end closure clamping and sealing station between a retracted inactive position and an extended active position in which the opposed work surfaces of the bottom end closure pressure pad and mandrel engage the layers of the bottom end closure in a clamping relationship;
• said bottom end closure horn and back-up means being operable to move from the retracted inactive position to the extended active position when a container is located at the bottom end closure activating station and return to the retracted inactive position after remaining in the active position with the horn energized a predetermined period of time sufficient to activate the thermoplastic material of the bottom end closure;
• said mandrel being movable from the bottom end closure activating station after said predetermined period of time to carry the container with the activated thermoplastic upon retraction of said bottom end closure horn and mandrel with respect to each other to the bottom end closure clamping and sealing station;
• said bottom end closure pressure pad and mandrel being operable to move from the retracted inactive position to the extended active position when the container with the activated thermoplastic of the bottom end closure thereof moves into the bottom end closure clamping and sealing station to clamp the layers of the bottom end closure with activated thermoplastic together and return to the retracted inactive position after remaining in the active position a predetermined period of time sufficient to permit the activated thermoplastic to cool and set and form a seal between the layers of the bottom end closure.