Automated warehouse system and retreat mechanism

An automated warehouse system comprising:

• a rack including a plurality of floors each including a plurality of floor panels adjacent to each other, the floors permitting a transportation robot to travel along surfaces of the floors, the plurality of floors being divided into a first section and a second section spaced from each other with a gap in between;
• and
• a retreat mechanism including a first member located adjacent to the floors in the first section and swingable around a first axis parallel with the surfaces of the floors and a second member located adjacent to the floors in the second section and swingable around a second axis parallel with the surfaces of the floors, the retreat mechanism establishing a first configuration to be located in the gap to permit the transportation robot to travel between the first section and the second section and a second configuration to retreat from the gap to unclose the gap, wherein
• when the retreat mechanism establishes the first configuration, the second member supports the first member on an upper surface of the second member, wherein
• when the retreat mechanism establishes the second configuration, a shield wall becomes receivable into the gap, the shield wall shielding the first section and the second section from each other.