US 2003/0070397 A1 · Method and apparatus for closing open end of carton blank

Abstract

The closure system of the present invention includes a pressure pad of conventional design which is urged against the external surfaces of a plurality of loosely associated overlying prefolded end side wall portions of the bottom end of a carton blank which is disposed on a mandrel which includes a backup pad disposed within the carton and contiguous to the internal surfaces of the prefolded end side wall portions to thereby capture the prefolded end side wall portions between the pressure pad and the backup pad. The force for urging the pressure pad initially against the loosely associated overlying prefolded end side wall portions and thereafter providing a sealing pressure against the infolded end side wall portions and maintain this sealing pressure for a time sufficient to permit solidification of the softened heat-sealable component of the carton blank, is generated by means of a piston/cylinder operating through a pivoted arm whose distal end carries a cam follower that is moved against a linearly reciprocative cam which is operatively associated with the pressure pad. The contour of the cam is chosen to provide for maximum distance of movement of the cam, at a relatively low pressure applied by the piston/cylinder, to initially urge the loosely infolded portions of the carton bottom into their desired permanent positions relative to one another, followed by minimum distance of movement of the cam at a relatively high pressure to urge the contiguous ones of the overlying infolded end side wall portions intimately against one another, and hold the same under high pressure as the heat-sealing layer or coating thereon solidifies and bonds the overlying end side wall portions together to define a closed bottom for the carton.

Claims16

Dependent claims

Apparatus for effecting the closure of an open end of a carton blank which includes a heat sealing component, following the partial infolding of portions of the end side walls of the blank into at least partial overlying relationship to one another comprising,

a cam having a rear face and a camming face, said camming face including a plurality of camming surfaces which vary in geometry, said camming surfaces including at least a convex radiussed camming surface which transitions into a concave radiussed camming surface, said transition occurring along an imaginary line drawn at an angle of 6 degrees from the vertical and wherein each of said radiussed surfaces is tangent to said imaginary line and to each other,
said cam being mounted for linear movement relative to the is partially infolded portions of the end side walls of the carton blank.

a cam mounted for reciprocative linear movement toward and away from the partially infolded end side wall portions, said cam having a camming surface,
a support arm having distal and proximal ends, said proximal end being mounted for pivotal movement of said distal end of said arm along a path which is substantially perpendicular to the direction of linear reciprocation of said cam,
a cam follower mounted on said distal end of said support arm and disposed in operative juxtaposition to said camming surface of said cam whereby pivotal movement of said support arm moves said cam follower along said camming surface of said cam and effects corresponding linear movement of said cam,
a pressure pad mounted for linear movement with said cam and disposed in juxtaposition to the infolded end side wall portions of the carton blank.

1 more element

A method for the closure of an open end of a carton blank including a heat-sealable component, wherein the end side walls adjacent the open end of the carton are heated to at least their heat-sealing temperature and initially infolded to partially close the open end of the carton, comprising the steps of

capturing the heated and initially infolded end side walls of the carton between a rigidly mounted backup pad disposed within the interior of the carton blank and a pressure pad disposed externally of the carton blank and mounted for reciprocative movement toward and away from said backup mandrel,
disposing a linearly reciprocative cam in operative relationship to said pressure pad to apply pressure to said pad upon linear movement of said cam toward said pressure pad,
providing on said cam a camming face disposed opposite said pressure pad,
providing a cam follower disposed adjacent to and in operative relationship to said camming surface,
applying a force against said cam follower in a direction substantially perpendicular to the direction of linear movement of said cam to thereby move said cam and said pressure pad toward said backup pad by a distance sufficient to press the infolded end side wall portions of the carton blank into intimate overlying relationship to one another, and
maintaining said pressure applied to said infolded end side wall portions for a time sufficient to effect solidification and sealing of said infolded end side wall portions to one another and thereby close the end of the carton blank.

3 more elements

Dependencies are inferred from the claim text.

Method and apparatus for closing open end of carton blank

Life of this patent

Method and apparatus for closing open end of carton blank

Life of this patent

Abstract

Claims16