It is not yet possible to fully automate the harvesting of vegetables and lettuce. But subsequent work such as washing, weighing and packaging can be done directly in the fields, as a result of which the process is speeded up considerably – so that very fresh products are then available to consumers. This task is carried out by special machines from Josef Zeyer GmbH. In the fields, the impressive machines can be controlled with a remote control unit connected to the vehicle by means of chainflex cables from igus.
Josef Zeyer GmbH builds harvesting machines for vegetables and lettuce, which are always designed and manufactured according to customer specifications. The mobile machines reach an impressive size of up to 10 x 9 metres (when extended), so that the just-harvested produce can be processed as quickly and freshly as possible. The harvest is washed, portioned, packed and palletised manually by staff from a bridge whilst still in the field. It then travels via a conveyor belt to the inside of the harvesting vehicle, where it can then be further processed.
The machine travels in the field at around 40 metres per hour, either automatically or sensor-controlled in 'platooning' mode behind a tractor. However, the driver must still be able to readjust, for which - as well as for turning at the end of the field - he uses a wired remote control. In addition to the drives and steering, which are controlled electronically via CAN bus, the level control, i.e. the distance between the harvester and the ground, is also controlled via remote control.
It is true that the flexible cable connecting the remote control and the vehicle does not have to perform a high number of cycles or extreme movements. Nevertheless, the stresses and strains should not be underestimated. The cables are exposed to UV rays and moisture, but in particular to various torsions and very different temperatures. And, as they are often pulled along the ground, the amount of wear increases.
Since conventional cables do not meet the ZEMA requirements for service life, the company basically uses chainflex cables from igus for remote controls. The chainflex cables have a completely different design than those for static applications: the principle of cores wound in bundles ensures that the tensile and compressive forces acting on the individual cores during movement are balanced. This creates an essential prerequisite for a long service life in moving applications - without broken cores and corkscrews. The high-quality materials and the special extrusion process prevent further causes of failure, such as jacket abrasion and insulation damage.
Twistable chainflex cables from the CFROBOT9 series are used in the ZEMA machines. The cables achieve a long service life in the field and make the handling of the remote control easier as they are flexible and therefore more mobile.
ZEMA purchases the cable sets as a ready-harnessed energy supply. This has the advantage that the customer saves a lot of time and does not have to keep plug-in connectors or other accessories ready. And despite the commitment to one standard, Josef Zeyer GmbH remains flexible because the harnessed cables can be ordered in different lengths.