Reinforced lightweight plastic packages

Claim 1

In a thin walled, light-weight, relatively flexible, molded plastic package having first and second re-entrant recesses respectively at opposite sides of the package, the package stiffened against crushing, comprising (a) said first re-entrant recess at one side of the package containing sufficient of a predetermined quanity of an expanded synthetic resin as to substantially fill said recess, (b) said expanded resin cured to form a hardened re-inforcing core in said first re-entrant recess and integrally with the package to stiffen same against crushing, whereby an article or articles placed in the second re-entrant recess at the opposite side of the package are protected against crushing, (c) said first recess extending lengthwise at least part way about said second recess having rectangular frame configuration, (d) and including a base sheet supporting said frame core, and there being a second frame core consisting of expanded resin and supported on the base sheet within another first re-entrant recess defined by the package which also defines another second re-entrant recess surrounded by the second frame, the base sheet being foldable to bring said frames into superposed relation protecting articles in said second re-entrant recesses. (e) and including a cover sheet over a side of the package to cover said first re-entrant recess and said core, and attached to the package.

Claim 7

The method of reinforcing a thin walled. light-weight, relatively flexible and crushable molded plastic package having first and second re-entrant recesses respectively at opposite sides of the package, that includes: (a) introducing into said first re-entrant recess at one side of the package sufficient of a predetermined quantity of an expansible synthetic resin as to substantially fill said recess when expanded, (b) providing a pressure wall at said side of the package to close said first recess and confine the resin as it expands causing flow ofthe expanding resin parallel to the wall and to substantially fill said recess, (c) and allowing said expanded resin to cure and form a hardened re-inforcing core in said first re-entrant recess and integrally with the package to stiffen same against crushing, whereby an article or articles placed in the second re-entrant recess at the opposite side of the package are protected against crushing, and (d) including removing said pressure wall away from the package after the resin has completed its expansion.

Claim 8

The method of reinforcing a thin walled. light-weight, relatively flexible and crushable molded plastic package having first and second re-entrant recesses respectively at opposite sides of the package, that includes: (a) introducing into said first re-entrant recess at one side of the package sufficient of a predetermined quantity of an expansible synthetic resin as to substantially fill said recess when expanded, (b) providing a pressure wall at said side of the package to close said first recess and confine the resin as it expands causing flow ofthe expanding resin parallel to the wall and to substantially fill said recess, (c) and allowing said expanded resin to cure and form a hardened re-inforcing core in said first re-entrant recess and integrally with the package to stiffen same against crushing, whereby an article or articles placed in the second re-entrant recess at the opposite side of the package are protected against crushing, and (d) including removing said pressure wall away from the package after the resin has completed its expansion.