Are humans ‘made’ for sitting?
Are humans ‘made’ for sitting? The answer is no. Human beings are not made for sitting, but many of us do it for many hours a day without the right instructions and tools. Because of this, many people suffer from back or neck problems.
This is especially the case for drivers working in container cranes, and continuously looking downwards increases these problems. It is clear that sitting this way in moving machines results in fatigue, physical complaints, loss of efficiency and even sometimes damage and dangerous situations.
Specific crane characteristics
Besides drivers having to look downwards, each type of container crane has its own specific characteristics as well. STS cranes have high accelerations and decelerations when both moving forwards and backwards, shocks at the boom junctions and an impact of a possible E-stop.
Meanwhile, the RTG cabin has a different field of vision, compared to a STS crane. The ypical problems a RTG driver faces are highly underestimated.
Looking around while driving the machine and looking sideways under beams while searching for trucks leads to difficult postures. Because the spreader is closer to the cabin and the drivers’ spread legs are often an obstruction, the driver uses his side windows to look at the corner-castings.
Movements sideways, in combination
with the RTG’s rubber tires, create a swinging motion to the machine and the driver when starting and stopping.
A comparable situation is experienced with straddle carriers. However, with straddle carriers the speed is higher, and the sitting position is often perpendicular to the driving direction. The driver is seated upright with his head turned 90 degrees to the left or the right. A combination of trunk inclination with lateral flexion and/or axial rotation takes place in all type of cranes.
Unmanned equipment would be the best solution for these kinds of problems. The question is: is this a realistic scenario for all container terminals worldwide? For now, the answer again, is no. Many aspects such as flexibility, efficiency, labour, and culture require man-operated cranes for at least the coming ten years.
The solution to prevent fatigue, physical complaints, loss of efficiency, damage and dangerous situations is to analyse the typical circumstances, to provide the drivers with the right devices and to give them suitable instructions.
For example, considering the working posture in STS, RTG and RMG cranes and the ISO Standard 11226, ‘Evaluation of Static Working Postures’, we have to conclude that the crane driver requires a full trunk support.