Folding jaw cylinder

A folding jaw cylinder for a folding mechanism in a web-fed rotary printing machine, said folding jaw cylinder including a fixed front folding edge extending axially along a surface portion of said cylinder and having a first recess and a spaced, cooperating movable folding jaw, said folding jaw having a folding surface adjacent the surface of said cylinder and extending radially inwardly toward the center of said cylinder and having a second inner recess, said folding edge and folding jaw cooperating to form a folding gap with said first and second inner recesses cooperating to form a folding slot into which a portion of a collated stack of sheets may be forced by a folding blade to form a fold in said sheets, said fold in said sheets having a bulge portion extending into said folding slot, said folding jaw being movable toward said folding edge to contact said fold after said fold has been formed, said folding blade remaining in said fold during said movement of said folding jaw toward said folding edge, said folding jaw having a resilient friction increasing means having a coefficient of friction exceeding 0.18, said resilient friction increasing means projecting out of a notch in said folding surface and extending into said folding gap from said folding surface to press against said fold in said sheets radially outwardly from said bulge portion of said fold in said folding slot whereby said fold will be retained in said folding slot as said folding blade is moved out of contact with said sheets.