Apparatus and method for insertion of separating means into a forming stack of sheets discharged from a starwheel assembly

A method of creating stacks of sheets discharged from a starwheel assembly in a direction downstream from the starwheel assembly, the method comprising:

• providing a first separator finger including a first portion and a second portion coupled to the first portion, the first portion and the second portion defining a closed position where the first and second portions are substantially aligned and an open position where the first and second portions are separated by a greater relative distance than the closed position;
• feeding sheets to the starwheel assembly;
• discharging sheets from the starwheel assembly with a barrier;
• inserting the first and second portions in the closed position between two adjacent sheets within the starwheel assembly to retain a second sheet of the two adjacent sheets upstream of the first separator finger;
• separating the first sheet from a second sheet of the two adjacent sheets to form a completed stack downstream of the first separator finger;
• stacking sheets from the starwheel assembly to define a next stack upstream of the first separator finger;
• and
• rotating the second portion relative to the first portion from the closed position to the open position to create a gap between the completed and next stacks.

An apparatus for engaging successive sheets carried by a starwheel assembly in a direction from upstream of the starwheel assembly to downstream of the starwheel assembly and urging discharge of the sheets in a drop zone downstream from the starwheel and forming stacks of the discharged sheets downstream from the starwheel assembly in the drop zone, wherein the starwheel is mounted for rotation about a starwheel axis and has a periphery defining a cylindrical volume of the starwheel assembly extending parallel to the starwheel axis, the apparatus comprising:

• a barrier, a split separator finger, and an actuator arrangement, all operatively connected to the starwheel assembly;
• the barrier extending at least partially within the cylindrical volume of the starwheel assembly and being configured and operatively connected to the starwheel assembly for operatively engaging sheets carried by the starwheel while the sheets are disposed at least partially within the cylindrical volume of the starwheel and urging discharge of the sheets in a direction downstream from the starwheel into the drop zone;
• the split separator finger having first and second members thereof pivotably attached to one another about a pivot axis extending substantially parallel to the axis of the starwheel and having respective distal working ends thereof;
• the first and second members of the split separator finger being configured and operatively attached to one another in such a manner that the first and second members may be pivoted with respect to one another about the pivot axis from a closed position in which the working ends of the first and second members of the split separator finger are aligned closely enough to one another to be insertable between two adjacent ones of the successive sheets, and an open position in which the working ends of the first and second members of the split separator finger pivot apart from one another, to thereby urge separation of the two adjacent sheets between which the working ends of the split separator finger were inserted while in the closed position;
• the split separator finger being operatively attached to the starwheel assembly for movement along a path of motion including, a retracted position in which the working ends of the first and second members of the split separator finger are disposed within the cylindrical volume of the starwheel assembly, and an extended position in which the working ends of the first and second members of the split separator finger are disposed outside of the cylindrical volume of the starwheel assembly;
• and
• the actuator arrangement being operatively connected between the starwheel assembly and the first and second members of the split separator finger for moving the split separator finger along the path of motion and pivoting the working ends of the first and second members of the split separator finger between the closed and open positions thereof, to thereby urge formation of the stacks of the discharged sheets downstream from the starwheel assembly in the drop zone.