When the market-leading plastics processor Ensinger GmbH automated the material flow between the production zones, the newly built warehouse and the consignment stations at its parent plant in Nufringen, H+H Herrmann + Hieber installed an efficient system of distribution trolleys and transfer carriages.
The newly built warehouse at Ensinger is designed as a honeycomb store for long articles (bars, plates, etc.). The load-carriers (“skids”) are relatively light sheet structures that move on slide-rails. For transporting the skids outside the warehouse, strong auxiliary pallets are generally provided. The skids taken from the warehouse are placed on an auxiliary pallet and transported along with it.
For transport to and from the warehouse distribution trolleys and transfer carriages running on rails are installed: the skids are moved between the production zone and the warehouse by means of a transport trolley (transfer carriage), and between the warehouse and the consignment or further processing stations by means of a distribution trolley. The said distribution trolley serves two consignment stations and an additional conveyor stretch with an automatic crane, which links a number of sawing stations to the warehouse. To avoid idle times and waiting times at the work stations, these are designed so that the pallets provided by the distribution trolleys are each brought in by way of a separate conveyor stretch – with buffer positions – and taken back to the distribution trolleys via a second, separate conveyor stretch. Thus, so to speak, they move round a cycle.
These distribution trolleys carry out all transfers into and from the warehouse. Owing to the necessarily large number of working steps this conveyor stretch is exceptionally busy and had to be designed in a correspondingly dynamic manner.
The design of the distribution trolley and the transfer carriage is matched to the auxiliary pallets or skids that they have to transport. The skids are around 3.3 metres in length and a maximum of 1.2 metres wide. The auxiliary pallets are strong frames which support the skids at a total of eight points. The distribution trolley is in this case fitted with a fourfold telescopic fork. The skids recovered from store – owing to their light structure – are taken up at four points, raised, and transported to the planned transfer position. There, the skid is placed on the auxiliary pallet positioned on the conveyor stretch to the consignment station or to the automatic crane. For the return to store, the procedure is reversed: the skid in taken up from the auxiliary pallet by the telescopic fork, transported to the scheduled warehouse aisle and transferred to the storage and recover machine of the warehouse.
