The square lid of the hatch

## Square Luke's lid: Riddle of everyday life
The square lids of the hatches are inconspicuous, but fairly common elements of the city landscape. We constantly meet them on the streets, and, as a rule, do not think about their purpose, form and history. However, behind this seemingly simple detail hides a number of interesting facts and engineering solutions.
### Why a square, not a circle?
The most common question that arises at the sight of the square lid of the hatch: why is it not round? After all, a round hatch, it would seem, is easier in manufacture and more ergonomic. In fact, the main advantage of the square form is safe. A round cover can fall into the hatch if it is turned over. The square, thanks to its sides, always remains in place, even if it is accidentally turned. This is an important security factor, especially given the likelihood of unauthorized access to underground utilities. In addition, square lids are easier to lay in a row, forming an even surface, which is convenient for pedestrians.
### materials and technologies
The production of square lugs of hatches is a complex technological process that requires the use of durable and durable materials. Most often, cast iron, steel and composite materials are used. The choice of material depends on the load that the lid should withstand, as well as on operating conditions. For example, for maneuvered luies, especially strong and wear -resistant materials are needed that can withstand the significant weight of heavy vehicles. Modern technologies allow you to create hatches with improved characteristics: increased strength, resistance to corrosion and more attractive appearance.
### outside the function
Despite their functionality, the square lugs of hatches can become an element of urban design. In some cities they are decorated with different drawings, making them less noticeable or, conversely, attracting attention to them. In any case, these inconspicuous details of the city landscape play an important role in ensuring the security and uninterrupted operation of underground utilities. And although we rarely pay attention to them, they are an integral part of our daily life.