Delivery rack and delivery vehicle

A delivery vehicle comprising:

• a rack, the rack comprising:
• a casing;
• M pairs of supports, with M being an integer not less than two, that are provided inside the casing so as to extend in a depth direction and arrayed in M tiers at regular intervals in a predetermined direction that is one of an up-down direction and a left-right direction;
• and
• a lock mechanism configured to lock returnable containers housed while being supported so as to be slidable along the respective M pairs of supports,
• the rack being configured to house all the returnable containers of one or more prespecified sizes, wherein:
• the lock mechanism includes:
• M rotary lock main bodies that are respectively provided at the M pairs of supports and each unlock at a predetermined rotation angle;
• and
• a coupling member that couples the M rotary lock main bodies to one another and allows the M rotary lock main bodies to rotate in conjunction with one another;
• the predetermined rotation angle for unlocking is different for each of the M rotary lock main bodies, and the M rotary lock main bodies are configured to be driven to rotate by a single driving source;
• a protrusion that protrudes from each returnable container toward an outer side in an orthogonal direction orthogonal to the predetermined direction slides over the supports;
• and
• the protrusion has a notch that is engaged with one of the M rotary lock main bodies when locking the returnable container and disengaged from the one of the M rotary lock main bodies when unlocking the returnable container.