Two axles with heavy-duty rollers, a drawbar and space for three EUR-pallets – on first sight, the platform truck developed by Ruppel Hydraulik for a German car battery maker looks pretty much like “any ordinary” vehicle for moving materials around on site.
It is only once it is in use that the innovation achieved by the Ruppel engineers reveals itself: the set-down surfaces for the pallets are in the form of transverse conveyors. These allow (semi-)automated loading and unloading of the pallets at the touch of a button on the control panel at the front end of the truck. The staff can for instance position a trailer parallel to a handover station or a conveyor belt and convey a pallet onto the belt using the truck’s transverse conveyor system, without the need for any separate industrial trucks.
The three pallets, which each weigh up to 1.5 tonnes, can be picked up and set down one-by-one. The transverse conveyors are powered from a central power pack, which is fitted as an underfloor unit to save space and provides the required start-up power from a very compact footprint.
The valve block of the unit is based on the use of standard CETOP valves. This keeps costs to a minimum and makes integration simpler. As is typically the case for hydraulics, the intelligence resides in the switching interfaces and linking of the elements involved. In addition, Ruppel has managed to use the hydraulic unit to provide an additional function which ensures the safe transportation of the pallets. The conveyor belts do not just have an anti-slip surface. They have added protection in the form of something akin to the dropside on a flatbed trailer. In this case, it is a metal element which moves upwards out of the vehicle frame, thereby ensuring that the pallet is both properly centred and cannot slide off when the truck is going round a corner. This safety system is also powered via the hydraulic power pack.
According to information provided by the battery maker, the company has increased productivity in its material flow by 15% since the platform trucks were brought into service. As well as high power density and the ability to control additional functions, the hydraulic drive concept also has the advantage that the drive parameters can easily be adapted to changes in the operating conditions (e.g. different pallet weights).
It is true that these platform trucks were developed specifically with a user in the field of battery engineering in mind. But this concept, which extends the function of a tow tractor and trailer trains to include semi-automated loading and unloading, is of course ideally suited to other industries, particularly as additional requirements can easily be implemented. Getting the conveyor belts to switch off automatically on reaching the end position, for instance, is no problem at all, nor is implementing position detection of the trailer next to the loading and unloading stations.