Why are the lugs of the hatches round

Why are the hatches of the hatches round?
This question, it would seem simple, actually causes many interest and disputes. After all, the form of a hatch is not just aesthetics, but a matter of safety and practicality. The round shape of the hatch cover is not an accident, but the result of centuries -old engineering. Let's figure out why the circle.
Strength and stability:
A circle is a geometrically ideal figure that has an uniform distribution of load over the entire area. Unlike square or rectangular lids, round cannot fall into the hatch even with strong lateral pressure. Imagine a cargo machine acts on the square cover. The probability that it will turn and fall into the mine is significantly higher than that of the round. The round shape provides maximum stability and prevents accidents.
Simplicity of movement:
The round cover of the hatch is easily rolling. This is very important for those who work with hatches, for example, utilities. Moving a round cover is much more convenient than square or rectangular, especially in conditions of limited space or on a slippery surface. She can simply slide down the gutter or guide, which greatly simplifies the work.
Effective use of space:
Although this is not the most important factor, the round shape allows you to use the space inside the hatch as efficiently as possible. While the square cover takes up more than the place relative to the diameter of the shaft, the round cover tights tightly to its edges, providing a minimum distance and reducing the likelihood of garbage stuck.
In conclusion, we can say that the choice of round form for hatches covers is not just a tribute to tradition, but the result of a well -thought -out engineering solution that ensures safety, ease of use and saving space. This is another example of how simplicity and functionality can be an ideal combination.