US 4,617,211 A · Method and apparatus for skiving and hemming

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.

Claims7

Dependent claims

A blank for a container, said blank comprising:

first and second exterior heat sealable layers defining first and second surfaces of said blank and an intermediate layer;
and at least one skived and hemmed edge portion having a first skived region defining a sloped plane and a second skived region substantially parallel to said second surface disposed between said first skived region and the adjacent edge of said blank;
said sloped plane and said first surface of said blank defining an angle of less than about 30.degree.;
said edge portion having a fold along a line between said first and second skived regions, said second skived region covering said first skived region, and a portion of said second skived region being heat sealed to said first heat sealable layer, thereby defining a folded-over portion, said folded-over portion having one surface at least a portion of which is substantially flush with said first surface of said blank and another surface which forms an oblique angle with said second surface of said blank.

1 more element

Dependencies are inferred from the claim text.

Method and apparatus for skiving and hemming

Life of this patent

Method and apparatus for skiving and hemming

Life of this patent

Abstract

Claims7