Abstract: A method and apparatus for attaching a skirted end closure to a tubular paperboard container, the container having a continuous lapped seam from one end to the other. The interior surface of the container is layered with a thermoplastic, and the container wall includes a layer of metal foil. An annular induction coil is placed near the annular surface of contact between the end closure skirt and an end region of the container interior surface. Upon activation of the induction coil, the metal foil is heated by the usual eddy current effect, to thus soften the thermoplastic and adhere the end closure skirt to the container. The specific improvement in this combination is the addition to the coil of a field intensifier in the region of the lapped seam. The action of the intensifier partially overcomes the lessened heating effect which naturally occurs at the ends of the lapped seam.

Abstract: A method and apparatus are disclosed for skiving and hemming one or more edges of a paperboard web or blank to improve the sealing qualities of a container made from the paperboard. The paperboard is skived twice generally parallel to its edge, once to define an oblique surface and once to make a flat skived surface. The latter is folded over the former and heat-sealed to a heat sealable material adjacent the skived region, defining a wedge-shaped edge portion. The folded over part is preferably ironed to produce a substantially flat sheet, and the wedge-shaped edge is preferably reshaped at some point in the process to make the entire folded over surface substantially flush with the unskived surface to which it is sealed. The flat skived surface is preferably made by a milling procedure in which the milling teeth strike the material while moving in a direction opposite to that of the motion of the material.

Abstract: A method and apparatus are disclosed for skiving and hemming one or more edges of a paperboard web or blank to improve the sealing qualities of a container made from the paperboard. The paperboard is skived twice generally parallel to its edge, once to define an oblique surface and once to make a flat skived surface. The latter is folded over the former and heat-sealed to a heat sealable material adjacent the skived region, defining a wedge-shaped edge portion. The folded over part is preferably ironed to produce a substantially flat sheet, and the wedge-shaped edge is preferably reshaped at some point in the process to make the entire folded over surface substantially flush with the unskived surface to which it is sealed. The flat skived surface is preferably made by a milling procedure in which the milling teeth strike the material while moving in a direction opposite to that of the motion of the material.

Abstract: A method and apparatus are disclosed for skiving and hemming one or more edges of a paperboard web or blank to improve the sealing qualities of a container made from the paperboard. The paperboard is skived twice generally parallel to its edge, once to define an oblique surface and once to make a flat skived surface. The latter is folded over the former and heat-sealed to a heat sealable material adjacent the skived region, defining a wedge-shaped edge portion. The folded over part is preferably ironed to produce a substantially flat sheet, and the wedge-shaped edge is preferably reshaped at some point in the process to make the entire folded over surface substantially flush with the unskived surface to which it is sealed. The flat skived surface is preferably made by a milling procedure in which the milling teeth strike the material while moving in a direction opposite to that of the motion of the material.