Most materials have varying degrees of elasticity. If they are bent, they will restore their original shape with great strength. In human history, we must have noticed that the branches of saplings and young trees have great flexibility. Due to the use of this feature in many primitive cultures, the computer spring machine wedges a stick behind a special door or cage, or uses a slip knot to wrap a rod and pull it down; once the tension is released, the stick or rod will Rebound. They use this method to capture birds and beasts.
In fact, the bow uses the elastic spring of the young tree in this way; first pull the bow back, then let go to let it rebound. In the Middle Ages, computer spring machines began to appear in machinery, such as textile machines, lathes, and drilling machines. , Grind machine and saw. The computer spring machine operator gives a downward stroke by hand or foot pedal to pull the working machine down. At this time, a rod fixed on the machine with a rope bounces back and produces reciprocating motion.
The torsion resistance of an elastic material is not lower than its flexibility. As early as the 4th century BC, a torsion spring tensioned with a twisted tendon rope or wool rope was invented to replace simple springs to strengthen the stone crossbow and throw The power of stone machines. At this time people became familiar with that metal is more elastic than wood, keratin, or any such organic substances.
In order to find out why the sword is elastic, they conducted many experiments. As a result, his master Ketzibi invented a stone thrower. The spring of the stone thrower was made of curved bronze plates-actually the earliest leaf spring. .