same location

Several important categories of automated storage/retrieval systems can be distinguished. These

include:

1. Unit load AS/RS: This is typically a large automated system designed to handle unit

loads stored on pallets or other standard containers. The system is computer-controlled and the

S/R machines are automated and designed to handle the unit load containers. The unit load

system is the generic AS/RS.

2. Miniload AS/RS: This storage system is used to handle small loads (individual parts or

supplies) that are contained in bins or drawers within the storage system. The S/R machine is

designed to retrieve the bin and deliver it to a P&D station at the end of the aisle so that the

individual items can be withdrawn from the bins. The bin or drawer is then returned to its location

in the system. The miniload AS/RS system is generally smaller than the unit load AS/RS and is

often enclosed for security of the items stored.

3. Man-on-board AS/RS: The man-on-board AS/RS system represents an alternative

approach to the problem of storing and retrieving individual items in the system. Whereas the

miniload system delivers the entire bin to the end-of aisle pick station, the man-on-board system

permits the individual items to be picked directly at their storage locations. This offers an

opportunity to reduce the transaction time of the system.

4. Automated item retrieval system: These systems are also designed for retrieval of

individual items or small unit loads such as cases of product in a distribution warehouse. In this

system, the items are stored in single-file lanes rather than in bins or drawer. When an item is

to be retrieved, it is released from its lane onto a conveyor for delivery to the pickup station. The

supply of items in each lane is generally replenished from the rear of the retrieval system, so that

there is flow-through of the items, thus permitting first in first out (FIFO) inventory control.

5. Deep-lane AS/RS: The deep-lane AS/RS is a high density unit load storage system that

is appropriate when large quantities are to be stored but the number of separate types of material

is relatively small. Instead of storing each unit load so that it can be accessed directly from the aisle,

the deep-lane system stores up to 10 or so loads in a single rack, one load behind the next. Each

rack is designed for ‘flow-through’ with input on one side and output on the other side. Loads

are picked from one side of the rack system by a special S/R type machine designed for retrieval

and another special machine is used on the entry side of the rack system for input of loads.

1. The storage structure is the fabricated steel framework that supports the loads contained

in the AS/RS. The structure must possess sufficient strength and rigidity that it does not

deflect significantly due to the loads in storage or other forces on the framework. The

individual storage components in the structure must be designed so to accept and hold

the storage modules used to contain the stored materials.

2. The S/R machine (sometimes called a crane) is used to accomplish a storage transaction,

delivering loads from the input station into storage, or retrieving loads from storage and

delivering them to the output station. To perform these transactions, the storage/retrieval

machine must be capable of horizontal and vertical travel to align its carriage with the

storage compartment in the storage structure, and it must also pull the load from or push

the load into the storage compartment.

3. The storage modules are the containers of the stored material. Examples of storage

modules include pallets, steel wire baskets and containers, tote pans, storage bins, and

special drawers (used in miniload AS/RS systems). These modules are generally made

to a standard base size that can be handled automatically by the carriage shuttle of the

S/R machine.

4. The pickup and deposit stations are used to transfer loads to and from the AS/RS.

They are generally located at the end of the aisles for access by the S/R machine and

the external handling system that brings loads to the AS/RS and takes loads away. The

pickup stations and deposit stations may be located at opposite ends of the storage aisle

or combined at the same location. This depends on the origination point of the incoming

loads and the destination of the output loads. The P&D stations must be designed so that

they are compatible with the S/R machine shuttle and the external handling system.