Pallet or Unit Load AS/RS handle full pallets or containers that can weigh up to 1000 pounds. These automated storage and retrieval machines offer a completely automated solution in a relatively small space. In fact, Unit Load AS/RS units can form the structural members of the building that it is contained in, thus the term "rack supported building". These buildings are often extremely high, up to and over 100 feet and are completely filled with the automated storage / retrieval systems equipment.
The aisles that the storage and retrieval units (cranes) travel are only inches wider than the load being handled which is why careful consideration and engineering expertise must be utilized when designing this system. The units that travel and carry the loads often operate at speeds many times faster than conventional forklift trucks and can reach heights unheard of with even the most sophisticated industrial lift truck.
Unit Load AS/RS often use shuttle carts to transport the pallets from their storage location to the pickup and delivery (P&D) point. In a traditional system, there is only one shuttle cart working with the crane to extract the pallet in a single deep pallet rack storage location and transport it to the P&D station. However, there are other methods and technologies available to further increase the throughput and productivity of the AS/RS. For example, using double deep storage rack and a shuttle car that can extract pallets from the second depth position. This is used when there are limited SKUs stored there exists a desire to further maximize the footprint of the storage area. Another method could be to utilize two shuttles at once. In these system, greater efficiencies are gained since the system can support picking up or putting away two loads at a time. Finally, a deep lane system can be used when there is an extremely low number of SKUs stored, but there exists a large quantity of each SKU. There are many ways to design a deep lane system ranging from unique shuttle cars to pallet flow rack and combinations of each.