Shuttle wave sequencing conveyor

1. A material handling system including an automated storage and retrieval system (AS/RS), the AS/RS comprising:

vertically spaced levels storing articles and each level comprising a pickup and deposit (P/D) station that is horizontally positioned, wherein an arrangement of the P/D station in a sequence at each level collectively defines a ramped orientation;

a first wave conveyor and a second wave conveyor in a stacked arrangement having the ramped orientation to move the articles selectively in at least one flow direction to a respective P/D station positioned at each level;

a first subset of an article transfer mechanism to move the articles in a selected at least one direction from the first wave conveyor to a respective first P/D station at one level; and

a second subset of the article transfer mechanism to move the articles from a respective second P/D station at another level onto the second wave conveyor;

wherein each of the first wave conveyor and the second wave conveyor are separately folded back at their respective midpoints to reduce a longitudinal dimension for a given number of levels serviced.

2. The material handling system of claim 1 , wherein the first subset of the article transfer mechanism and the second subset of the article transfer mechanism comprise at least one right angle transfer conveyor subsystem positioned to transfer either (a) an article between the first P/D station and a juxtaposed portion of the first wave conveyor or (b) another article between the second P/D station and a juxtaposed portion of the second wave conveyor.

3. The material handling system of claim 1 , wherein the AS/RS comprises shuttles that move articles in aisles that each include a respective P/D station.

4. The material handling system of claim 3 , further comprising a controller that executes instructions to:

position selected articles on the respective P/D station by respective assigned shuttles;

selectively move the selected articles onto the first wave conveyor and the second wave conveyor by respective article transfer mechanisms in coordination with movement of the first wave conveyor and the second wave conveyor to create a sequenced flow of selected articles.

5. The material handling system of claim 4 , wherein:

a selected aisle having a P/D station and inventory locations on one side has shared inventory locations on an opposite side that are serviced by a selected shuttle that services the selected aisle;

the AS/RS has another aisle behind the shared inventory storage locations that is serviced by another shuttle, the other aisle having inventory storage locations on an opposite side to the shared inventory storage locations, and

the controller:

determines whether an article designated for delivery to the P/D station of the selected aisle is a slow mover;

in response to determining that the article is a slow mover:

directs the selected shuttle to move the article to a shared inventory location; and

directs the other shuttle to move the article from the shared inventory location to an inventory storage location.

6. The material handling system of claim 5 , wherein the controller, in response to determining that the article is not a slow mover, directs the selected shuttle to move the article to an inventory location.

7. The material handling system of claim 1 , wherein each P/D station comprises more than one buffering position.

8. The material handling system of claim 1 , wherein each of the first wave conveyor and the second wave conveyor are longitudinally offset to increase load clearances.

9. The material handling system of claim 1 , further comprising:

a hinged extender conveyor that transfer product to the first and second wave conveyor from their respective P/D station; and

a catwalk that is transverse to the hinged extender conveyor.