| Spring is an elastic (flexible) object, used to store and absorb mechanical energy. Springs are usually made out of materials, having high strength and elastic properties. General purpose springs are manufactured from high carbon steels, alloyed manganese, silicon and vanadium. Beryllium bronze, silicon-manganese bronze, tin-lead bronze are used for springs working in aggressive media.Small springs can be wound from pre-hardened stock, while larger ones are made from annealed steel and hardened after fabrication.
Types of springs:
According to design:
- coil springs or helical springs;
- Conical springs;
- Spiral springs;
- Belleville washer or Belleville springs;
- Leaf springs (For example: bows);
- Torsion springs.
According to load taking:
- Compression springs;
- Tension springs;
- Torsion springs;
- Bow springs;
Tension springs are designed to become longer under load. Their turns are normally touching in the unloaded condition. They have a hook, eye or some other means of attachment at each end for fastening.
Compression springs are designed to become shorter when loaded. The turns of compression springs do not touch each other in the unloaded condition. End turns are pressed to the adjacent turns and end surfaces of the springs are ground. To avoid the loss of stiffness, lengthy compression springs are arranged on mandrels or cups.
Turns of compression-tension springs experience twist tension under the influence of spring constant.
Theory:
In classical physics, a spring can be seen as a device that stores potential energy by straining the bonds between the atoms of an elastic material.
Hooke’s law of elasticity states that the extension of an elastic rod is linearly proportional to its tension, the force used to stretch it. In reality, this law holds only approximately and only when the deformation (extension or contraction) is small compared to the rod’s overall length. If the strain increases a specific limit (yield point), atomic bonds get broken or rearranged, and a spring may snap, buckle, or permanently deform. It is necessary to note that, many materials have no clearly defined elastic limit, and Hooke's law can not be meaningfully applied to these materials.
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Springs is one of the greatest mechanical inventions in history. No matter how far technology advances, springs are still widely used in numerous devices from clock parts to prosthesis to vehicle suspension and dashpot, to toys like slinky and pogo stick.
