scope:

The guideline is applicable to the cycle-time determination of transport sequences which are performed using cranes. Crane control can be manual, semi- or fully automatic (VDI 3653).

The following sequences of transport of unit loads or bulk material are considered:

• between two defined points
• into or out of a warehouse with a defined storage volume
• into or out of a warehouse with the storage volume varying stochastically

Working cycles between two defined points

The working cycle describes the transport from a starting point P₁ to a destination P₂ and back again, if required.

Example

• Loading of a machine, e.g. for changing an injection mould

Working cycles for warehouses with defined storage volume

The working cycle describes the transport between storage position E and retrieval position A in warehouses with defined storage volume, where the complete storage volume is stored or retrieved. Storage processes must not be interrupted by retrieval processes and vice versa.

Storage and retrieval positions can be arranged in different ways in warehouses. Such warehouses are characterised by identical loading units such as containers, pallets, skeleton containers, etc.

Examples

• Loading and unloading of a container vessel
• Clearing of a bulk-material warehouse

Working cycles for warehouses with storage volume varying stochastically

The storage sequences are characterised by stochastically varying storage and retrieval processes which alter the content of the warehouse continuously.

For cycle-time calculation, two representative storage points P₁ and P₂ are defined in such a manner that their mean cycle times for storage and retrieval processes correspond to sufficient accuracy to the mean value of the cycle times of all storage points. Therefore allowing a definition about the crane performance to be made.

Examples

• Warehouse for bulk material (such as coal, gypsum)
• Warehouse for unit loads (such as reel paper, coils)