Storage and retrieval machine
A storage and retrieval machine (SRM) is a storage device used to store, transfer and retrieve load units. The storage, transfer and retrieval performance of a warehouse system depends on the following factors of the storage devices used:
- design
- driving behavior
- aisle restriction
- load handling attachment
In addition, the number of storage devices plays a role. In addition to storage and retrieval machines, high-lift trucks, satellite vehicles and forklift trucks, among other things, can be used.
Storage and retrieval machines can be moved in three directions.
- In the longitudinal direction
- In a vertical direction
- In the transverse direction
It consists of a mast, chassis, lift truck, load handling device and control system.
Use of a storage and retrieval machine in an automated small parts warehouse (Image license: CC BY-SA 3.0, Author: Thomas Philippi)
When a storage and retrieval machine is moved in the longitudinal direction of the aisle, it means that it is transporting goods along an aisle on a rail. During the vertical movement, it moves along a mast and in the transverse direction, it is moved when, for example, a pallet is to be picked up or put down.
The speed of travel depends on the direction in which the storage and retrieval unit is moving, the payload and the total weight. Storage and retrieval units sometimes have to travel long distances and ultimately position the goods with millimeter precision. They have a lifting height of approx. 6 meters to even 50 meters.
Curved and lane-bound storage and retrieval units
Curved-track stacker cranes are suitable for low performance. The warehouse aisle can be changed with the help of a converter, i.e. via a rail network laid on the floor. This means that the stacker crane can travel along several warehouse aisles. According to their designation, aisle-bound stacker cranes are only ever used in one warehouse aisle. The use of an aisle-bound stacker crane is suitable for high performance.
A stacker crane can be controlled either manually or automatically. Automatic control can be implemented with the support of a warehouse management system.
For more information, see Resource Utilization in Material Flow Control.
Image source: © Corepics – Fotolia