Folding machine

Claim 1

In a sheet folding apparatus of the type including a primary folder having conveyors for transporting a sheet to folding stations, said folding stations including folding rolls operable to fold the sheet to a fraction of its original dimensions, a secondary folder having a folding station including folding rolls for performing additional folds on said folded sheet, said secondary folding station including conduits for emitting jets of air to the nip of said folding rolls; the improvement in said secondary folder comprising means for precreasing and urging said sheet toward the nip of said secondary folding rolls, said precreasing means comprising a thin, reciprocable creasing shoe overlying and engageable with said sheet when said sheet is located over said pair Of folding rolls, means for moving said creasing shoe into engagement with said sheet along a line parallel to the nip defined by said pair of folding rolls which line is generally normal to a previous fold line, control means responsive to the presence of a sheet at said pair of folding rolls for bringing said creasing shoe in contact with said sheet to partially direct said sheet into the nip of said rolls, and means for substantially simultaneously connecting said conduit with a source of air under pressure to completely direct said sheet into the nip of said rolls.