Carton stacking apparatus and methods

A method for stacking comprising:

• moving first and second pluralities of stacker shelves each along first and second endless paths, with each of the first and second endless paths including an operative section, with the operative sections being spaced and parallel, with the first and second plurality of stacker shelves extending towards each other in the operative sections, with the stacker shelves having an extended position and a retracted position in the operative sections, with a spacing between the stacker shelves in the operative sections being less in the extended position than in the retracted position;
• positioning corresponding stacker shelves in either the extended or the retracted positions in the operative sections;
• receiving an item on the corresponding stacker shelves in the extended positions in the operative sections, with the stacker shelves in the retracted positions in the operative sections being operatively spaced from the item received on the corresponding stacker shelves in the extended positions;
• and
• sequentially retracting the stacker shelves in the endless paths to stack the item;
• wherein moving the first and second pluralities of stacker shelves comprises moving first and second plurality of carriers each along the first and second endless paths;
• wherein positioning corresponding stacker shelves comprises sliding the first and second pluralities of stacker shelves relative to the first and second plurality of carriers moving along the first and second endless paths;
• and
• wherein sliding the first and second pluralities of stacker shelves comprises providing a cam follower on each of the first and second pluralities of stacker shelves;
• providing first and second cam tracks in each of the operative sections of the stacker sections;
• and switching the cam follower into one of the first and second cam tracks as the first and second pluralities of stacker shelves enter the operative sections of the endless paths.

Apparatus for stacking items comprising, in combination:

• first and second pluralities of stacker shelves each moving along first and second endless paths, with each of the first and second endless paths including an operative section, with the operative sections being spaced and parallel, with the first and second plurality of stacker shelves extending towards each other in the operative sections, with the stacker shelves having an extended position and a retracted position in the operative sections, with a spacing between the stacker shelves in the operative sections being less in the extended position than in the retracted position;
• a mechanism receiving an item and transferring the item to the corresponding stacker shelves in the extended positions in the operative sections, with the stacker shelves in the retracted positions positioned vertically within a vertical extent of the item positioned on the corresponding stacker shelves in the extended positions and in the operative sections being operatively spaced from the item received on the corresponding stacker shelves in the extended positions;
• and
• a switch positioning corresponding stacker shelves in either the extended or the retracted positions in the operative sections before the item is transferred by the mechanism.

An apparatus for stacking items comprising, in combination:

• first and second pluralities of stacker shelves each moving along first and second endless paths, with each of the first and second endless paths including an operative section, with the operative sections being spaced and parallel, with the first and second plurality of stacker shelves extending towards each other in the operative sections, with the stacker shelves having an extended position and a retracted position in the operative sections, with a spacing between the stacker shelves in the operative sections being less in the extended position than in the retracted position;
• a switch positioning corresponding stacker shelves in either the extended or the retracted positions in the operative sections;
• a mechanism receiving an item and transferring the item to the corresponding stacker shelves in the extended positions in the operative sections, with the stacker shelves in the retracted positions in the operative sections being operatively spaced from the item received on the corresponding stacker shelves in extended positions;
• first and second plurality of carriers each moving along the first and second endless paths, with the first and second pluralities of stacker shelves being slideable relative to the first and second plurality of carriers moving along the first and second endless paths;
• a cam follower on each of the first and second pluralities of stacker shelves;
• and
• first and second cam tracks in each of the operative sections of the stacker sections, with the switch switching the cam follower into one of the first and second cam tracks as the first and second pluralities of stacker shelves enter the operative sections of the endless paths.