The torsion resistance of the elastic material does not depend on its flexibility. During the Greek Empire (presumably in the 4th century BC), a torsion spring that was twisted with a reins or a wool rope was invented to replace the simple springs to strengthen the power of the stone shovel and the slinger. At this time people began to realize that metals are more elastic than wood, keratin or any such organic matter. Philo (who was written about 200 BC) introduced it as a new discovery. He estimates that the reader is incredible. The elasticity of the Celtics and the Spanish swords caught the attention of his predecessors in Alexandria. In order to find out why the sword is flexible, they conducted many experiments. As a result, his master, Ketsiby, invented the riprap machine. The spring of the ripper was made of curved bronze plates - actually the earliest leaf springs; Philo himself further improved these ripraps. The creative Ketsiby, after inventing the riprap, came up with another type of riprap machine - a flexible work that was created by the use of air inside the cylinder under pressure.
It was only a long time later that people thought that if you compress a screw instead of bending a straight rod, the metal spring will store more energy. According to Braunellessky's biography, he made an alarm clock, which used several generations of springs. It has recently been pointed out that this alarm clock is included in a mechanical manual at the end of the 15th century with some exotic spiral spring clocks. These springs are also used in modern mousetraps. A timepiece with a coil spring (horizontal compression instead of vertical compression) has definitely been used around 1460, but it is basically a luxury of the royal family. After about a century, the clock with a spring became a middle class. The symbol of class people.