US 5,331,791 A · Method and apparatus for the manufacture of a resealable package

Abstract

It is often desired to again seal packages, consisting initially of foils hot-sealed with one another, after opening and partial removal of the content in the package in order to at least partially separate the remaining content in the package from the environment. A resealing area is provided for this purpose besides the hot-sealing area, with which the top and the bottom foil are connected to one another, which resealing area consists of individual closing elements which, fitting into each other, are provided in the two foils. The foils are not threadlike connected with one another in the resealing area. Rather dotlike closing elements exist, which also permit a small undercut. They are formed in matrixes without a top die, which matrixes are thereby subjected to an underpressure, whereas the other side of the foil is under an excess pressure. The deformation is thus brought about purely pneumatically. The shape of the closing elements can in this manner be designed in many ways and can be easily adapted to the requirements of each individual package.

Claims17

Dependent claims

A method of manufacturing a resealable package having a top foil and a bottom foil which are hot-sealed together at a peripheral edge of the package to form a resealable portion and to seal a packaging material arranged therebetween, the resealable portion having a plurality of pairs of complementary mateable closure elements formed into the peripheral edge of the top foil and the bottom foil, the method comprising the steps of:

clamping the resealable portion at the peripheral edge thereof between a first member and a second member of a forming tool to hermetically isolate the resealable portion from an outer surroundings;
drawing a first surface of at least one of the top and bottom foils of the resealable portion against a plurality of stationary heating elements of said first member by negative pressure,
heating a plurality of areas of the resealable portion drawn against said heating elements to a temperature at which said areas are plasticized;
separating said areas from said heating elements by applying positive pressure to said first surface of the resealable portion while simultaneously drawing said heated areas into a plurality of opposing recesses in said second member;
and
cooling and evacuating said recesses to form the closure elements, said recesses being evacuated by applying negative pressure to a second surface of the other of said at least one of the top and bottom foils of the resealable portion.

3 more elements

An apparatus for making a resealable package, the package having a top foil and a bottom foil hot-sealed together at a peripheral edge of the package to form a resealable portion and to seal a packaging material arranged therebetween, the resealable portion having a plurality of pairs of complementary mateable closure elements formed into the peripheral edge of the top foil and the bottom foil, the apparatus comprising:

means for supplying positive or negative air pressure;
a forming tool positioned downstream of a sealing station along a packaging line, the forming tool including first and second parts having first and second opposing pressure surfaces respectively, said pressure surfaces cooperating to relatively movably clamp the resealable portion therebetween along the peripheral edge of the resealable portion;
said first part also having a through recess communicating with the resealable portion, a plurality of heating elements disposed within said through recess, and an outlet passage connecting said through recess to said means for supplying positive or negative pressure;
said second part also having a plurality of matrix-like recesses formed on said second pressure surface and conforming in size and spacing to the closure elements, means for cooling said second part, and a plurality of connecting bores connecting said matrix-like recesses to said means for supplying positive or negative pressure;
whereby said means for supplying positive and negative pressure draws the resealable portion against said heating elements to form plasticized portions of the resealable portion before simultaneously drawing and forcing said plasticized portions from said heating elements into said recesses to form said closure elements.

2 more elements

Dependencies are inferred from the claim text.

Method and apparatus for the manufacture of a resealable package

Life of this patent

Method and apparatus for the manufacture of a resealable package

Life of this patent

Abstract

Claims17