US 12,006,149 B2
Storage and retrieval system
John G. Lert, Jr., Wakefield, MA (US); and William J. Fosnight, Windham, NH (US)
Assigned to Walmart Apollo, LLC, Bentonville, AR (US)
Filed by Walmart Apollo, LLC, Bentonville, AR (US)
Filed on Jun. 17, 2022, as Appl. No. 17/843,124.
Application 16/594,647 is a division of application No. 15/171,802, filed on Jun. 2, 2016, granted, now 10,435,241, issued on Oct. 8, 2019.
Application 17/843,124 is a continuation of application No. 16/594,647, filed on Oct. 7, 2019, granted, now 11,365,049, issued on Jun. 21, 2022.
Claims priority of provisional application 62/169,615, filed on Jun. 2, 2015.
Prior Publication US 2022/0315333 A1, Oct. 6, 2022
Int. Cl. B65G 1/04 (2006.01); B65G 1/137 (2006.01)
CPC B65G 1/0492 (2013.01) [B65G 1/0478 (2013.01); B65G 1/1378 (2013.01)] 18 Claims
OG exemplary drawing
 
1. An automated storage-and-retrieval system, comprising:
a multi-level storage structure comprising a plurality of racks separated by aisles, each rack comprising a set of horizontal container supports configured to store containers, which hold objects therein, at a plurality of storage levels within each aisle, and a set of inclined or vertical tracks disposed between and connecting levels of the multi-level storage structure;
a first set of vertical load bearing features on a first inclined or vertical track of the set of inclined or vertical tracks; and
a second set of vertical load bearing features on a second inclined or vertical track of the set of inclined or vertical tracks spaced from the first set of vertical load bearing features across an aisle of the aisles, the first and second sets of vertical load bearing features facing each other across the aisle along a third axis perpendicular to a first axis;
a mobile robot configured to transport a selected one of the containers to and from the multilevel storage structure, the mobile robot comprising:
a caster wheel;
a first traction drive and a second traction drive, the first traction drive comprises a first motor and a first wheel driven by the first motor, and the second traction drive comprises a second motor and a second wheel driven by the second motor, wherein the first and second wheels and the caster wheel are configured to contact a common horizontal surface supporting the mobile robot permitting steering and configured to turn the robot using the first wheel and the second wheel while on the horizontal surface with the first traction drive controlled to drive fore or aft the first wheel and the second traction drive controlled to drive fore and/or aft the second wheel while operating on the horizontal surface including enabling the mobile robot to move across the horizontal surface; and
a first sprocket or pinion on a first side of the mobile robot, and a second sprocket or pinion on a second side of the mobile robot opposite the first side, the first and second sprockets or pinions having a retracted position and an extended position;
the first and second sprockets or pinions having axes of rotation parallel to the first axis and configured to selectively engage at two positions of the set of inclined or vertical tracks of the multi-level storage structure while in the extended position, and propel the mobile robot along a second axis along the inclined or vertical tracks of the multi-level storage structure;
first and second passive followers having axes of rotation parallel to the first axis, the first and second passive followers configured to engage the first and second tracks of the set of inclined or vertical tracks;
wherein the first and second sprockets or pinions are configured to engage the first and second sets of vertical load bearing features by moving oppositely of each other along the third axis.