Corrugated sheet unstacking and feeding apparatus

A corrugated sheet unstacking and feeding apparatus for removing sheets from a vertical stack of sheets and feeding the sheets in a shingled fashion along a feed axis with each sheet being laterally centered with respect to the feed axis;

• comprising:
• a powered elongated feed conveyor extending along a feed axis and having a receiving end and a discharge end;
• elevator means for receiving a vertical stack of corrugated sheets and moving the stack upward until the top of the stack reaches a desired elevation above that of the feed conveyor;
• block handling means adjacent the receiving end of the feed conveyor for (1) removing a block of sheets from the elevated stack, (2) inverting the block of sheets, (3) aligning lateral edges of the sheets within the block as the block is being inverted, (4) laterally centering the block of sheets with the feed axis, and (5) depositing the centered block of sheets on the receiving end of the feed conveyor laterally centered with the feed axis;
• the block handling means comprising:
• a block inverting carriage movable with respect to the elevated stack of sheets and the elongated feed conveyor, the block inverting carriage being both vertically movable from an elevated position adjacent the top of the elevated stack to a lowered position adjacent the receivng end of the feed conveyor, and being movable from a first pivot position for receiving an uppermost block of sheets from the elevated stack through a second pivot position in which the block of sheets is vertically oriented, and to a third pivot position in which the block of sheets is inverted from its original orientation in the elevated stack;
• the block inverting carriage including laterally opposed alignment elements mounted to the carriage for movement in unison with it;
• drive means operably connected between the carriage and alignment elements for moving the alignment elements laterally inward with respect to the moving carriage and the feed axis for (1) aligning the edges of the sheets within the block with each other and (2) shifting the block of sheets laterally with respect to the moving carriage to center the block relative to the feed axis;
• and
• shingling means along the feed axis between the receiving end and the discharge end of the feed conveyor for engaging the moving inverted laterally aligned block and feeding the sheets to the discharge end in a sequential shingled fashion.