Patent ID: 7137941

Claim:
A hemming apparatus comprising: means for conveying successive carton blanks along a paper line axis of said apparatus; means for forming a crease a predetermined distance from an edge of said carton blank and folding said edge along said crease in a predetermined plane; means for heating a thermoplastic coating on said unfolded portion of said edge adjacent to said crease; means for folding said folded edge, under said heated unfolded portion of said edge, said folding means comprises a spiral attached to a vacuum hemmer; means for sealing said folded portion of said edge under said unfolded portion of said edge having said heated thermoplastic coating to form a sealed hem on said edge of said carton blank; said vacuum hemmer comprises a belt having a plurality of holes, said belt being positioned in a vertical plane around two spaced apart idler rolls, a drive roll and a take-up roll; a plate having a plurality of openings is positioned immediately above a lower horizontally traveling portion of said belt; a hood positioned on top of said plate for enabling a vacuum to retain each of said carton blanks as they move along said belt; and said spiral having predetermined contoured surfaces and mounted alongside said lower horizontally traveling portion of said belt for turning up to 180 degrees said previously folded edge of said carton blanks to place said folded edge under said heated unfolded portion of said edge.