Roller positioning method and apparatus for buckle-type paper folding machine

Claim 1

A buckle-type folding machine for successively folding sheets of paper comprising a frame, first and second elongated rollers disposed in parallel relation defining a nip through which paper sheets can be successsively passed and folded, means for supporting said first roller for rotational movement about its axis, means for rotably driving said rollers, an elongated fold plate having a paper receiving cavity into which said sheets are directed for buckling said sheets prior to folding, said fold plate having a leading edge in close proximity to said second roller said fold plate being disposed at an acute angle to a line passing through the centers of said rollers, means for supporting said second roller for rotational movement about its axis as well as limited lateral movement relative to said frame in a direction perpendicular to its axis and parallel to said fold plate, said second roller supporting means including a pair of bearing blocks between which the ends of said second roller are rotably journaled, a pair of channels fixed to said frame, said bearing blocks each being slidably disposed within a respective one of said channels, said channels being mounted in a plane parallel to said fold plate so that upon passage of a folded sheet through said nip said second roller separates from said first roller through non-radial movement in a direction parallel to the plan of said elongated fold plate to allow passage of said sheets while not substantially changing the spacing between said second roller and said fold plate leading edge, a pair of rockers pivotedly mounted on said frame and having first and second legs, means coupling the first leg of each rocker to one of said bearing blocks so that lateral movement of said bearing blocks within said channel upon passage of said folded sheets through said nip causes rotational movement of said rockers, and bias means acting on the second leg of each said rocker for urging said rockers, bearing blocks, and second roller to their original positions following passage of a folded sheet through said nip.