Method and apparatus for forming carton opening arrangement, and cartons made thereby

• US 5,255,494 A
• Filed: 05/01/1992
• Issued: 10/26/1993
• Est. Priority Date: 12/10/1991
• Status: Expired due to Fees

• Current Assignee: Tetra Alfa Holdings, S.A. (Tetra Laval Holdings BV)
• Original Assignee: Tetra Alfa Holdings, S.A. (Tetra Laval Holdings BV)
• Inventors: Doyle, Eric P.
• Primary Examiner(s): Coan, James F.
• Application Number:
  US07/877,072
• Time in Patent Office: 543 Days
• Field of Search: 53/477, 53/410, 53/412, 53/375.9, 53/377.7, 53/133.1, 53/133.2, 53/370.9, 53/370.8, 53/370.7, 53/373.9, 53/373.8, 53/374.2 , 53/371.9, 493/87, 206/631.3
• US Class Current: 53/477
• CPC Class Codes: B31B 50/642 using sealing jaws or sealing dies
• CPC Class Codes: B31B 50/8122 Applying patches
• CPC Class Codes: B65B 7/18 by collapsing mouth portion and subsequently folding-down or securing flaps
• CPC Class Codes: B65D 5/067 Gable-top containers

Abstract

A process for forming an easy-opening arrangement for gable-top cartons is described. A tape is applied to the inside of the pouring spout in order to stiffen the panels, while reducing the force required to separate the thermoplastic seal. The tape is bonded to the thermoplastic surface layer of the carton by an adhesive. During the hot air heating of the carton top prior to sealing, the area where the tape is located is not exposed to the hot air. During closing of the sealing jaws, surfaces on the opposed faces of the sealing jaw urge the adhesive into the space above the edge of the pouring spout to form an impermeable seal. The location of the tape on the carton blank and the apparatus for heating and sealing the carton are also described.

Claims

1. Apparatus for closing and sealing cartons of the type having a bottom, side walls, front and back walls, a gable-top heat-sealed closure in which the front and back walls are sealed together and the side walls have fin panels that are folded back and sealed between the front and back walls in a sealing fin along the ridge of the gable, and having an openable closure in which the sealing fin may be separated to expose the fin panels and by separating the fin panels from the front and back walls in the seal fin to form a pouring spout, the pouring spout having a reinforcing tape bonded by an adhesive to the interior surface along the edge of the fin panels, the apparatus comprising:

filling means for filling liquid content in the carton through the open top;

heater means for heating the front and back walls and the fin panels on one of the side walls while avoiding heating of the reinforcing tape;

closing means for closing the gable-top of the carton, said closing means including means for displacing the adhesive toward the edge of the fin panels while maintaining the position of the tape, said closing means including a pair of opposed sealing jaws, said sealing jaws being positioned for clamping the gable top of a carton between them, said sealing jaws each have clamping surfaces in position for clamping the gable top of a carton between them, said clamping surface each having a recess in said clamping surface, said recess overlying the edge of the fin panels and the upper edge of the reinforcing tape when a carton is clamped between the clamping surface, said clamping surfaces each including a second recess which overlies the lower edge of the tape.

2. The apparatus according to claim 1 wherein the first recess in each clamping surface has a depth that is greater than one-half of the combined thickness of the fin portions and the front and back walls and the tape in the sealing fin.

3. Apparatus for closing and sealing cartons of the type having a bottom, side walls, front and back walls, a gable-top heat-sealed closure in which the front and back walls are sealed together and the side walls have fin panels that are folded back and sealed between the front and back walls in a sealing fin along the ridge of the gable, and having an openable closure in which the sealing fin may be separated to expose the fin panels and by separating the fin panels from the front and back walls in the seal fin to form a pouring spout, the pouring spout having a reinforcing tape bonded by an adhesive to the interior surface along the edge of the fin panels, the apparatus comprising:

filling means for filling liquid contents in the carton through the top when the top is open;

heater means for heating the front and back walls and the fin panels on one of the side walls;

closing means for closing the gable-top of the carton, said closing means including means for causing at least some of said adhesive to be displaced into a region located between upper edges of the fin panels and an upper portion of the sealing fin while maintaining the position of the tape.

4. The apparatus according to claim 3, wherein said heating means includes means for directing heated air at the front and back walls and the fin panels of the one side wall while not directing heated air at the reinforcing tape.

5. The apparatus according to claim 3 wherein said closing means includes a pair of opposed sealing jaws, said sealing jaws being positioned for clamping the gable top of a carton between them.

6. The apparatus according to claim 5 wherein said sealing jaws each have clamping surfaces in position for clamping the gable top of a carton between them, said clamping surfaces each having a recess in said surface, said recess overlying the edge of the fin panels and the upper edge of the reinforcing tape when a carton is clamped between the clamping surfaces.

7. The apparatus according to claim 3, wherein said closing means includes two opposed sealing jaws and said heating means heats said adhesive by radiant heat, said means for causing at least some of the adhesive to be displaced including each of said sealing jaws being provided with a bar portion for applying pressure to the sealing fin to cause the heated adhesive to flow and a relief area that is recessed with respect to said bar portion for allowing the heated adhesive to flow into the region located between the upper edges of the fin panels and the upper portion of the sealing fin, the relief area being positioned above said bar portion.

8. The apparatus according to claim 7, wherein said relief area is an upper relief area, and including a lower relief area that is recessed with respect to said bar portion, said bar portion being positioned between said upper and lower relief areas.

9. The apparatus according to claim 3 wherein said heater means includes a plurality of distributor elements spaced apart to form slots to receive portions of an open gable-top carton, said heater means including means for supplying heated air to said distributor elements.

10. The apparatus according to claim 9 wherein one of said slots is positioned to receive the portion of the carton top where the reinforcing tape is located, said one slot having opposite walls, one of said slot walls having a plurality of holes directing heated air against the corners between the walls of the carton to soften the thermoplastic coating, and the other of said slot walls having an absence of holes, whereby the reinforcing tape is heated only by radiant heat while the corners of the carton top are heated by air from said holes.