by Jenny Knodell, IQS Editor
What do cell phones, mattresses, satellites, pens, seat belts and clocks all have in common? I’ll give you a hint—they all use simple yet ingenious devices that have been integral parts of products and machinery for hundreds of years. Any ideas yet? Okay one more clue—you’ve played with them many a time as a child, either jumping on them as they boing up and down, or watching them descend a staircase in a very slinky manor. They’re springs—those coils of metal cords that store mechanical energy and are easily able to return to their original shape after twisting, bending, stretching and squeezing.
Perhaps the first thing that comes to mind when thinking about springs is a Slinky or pogo stick. In fact, they are used for so much more than childhood entertainment. The very first springs were used in mattresses and chair upholstery for a more comfortable seat, and clock springs replaced the old system of weights, making more reliable and portable timekeepers. As technology became more advanced, the need for springs grew. Today, they are important parts of modern electronics and machinery.
Clock Spring Pogo Stick Spring
Even modern springs are very simple to manufacture. Usually made from cold formed steel cord, springs are coiled by fully automated CNC machines, which may produce up to 2,000 an hour, depending on their size. One or both ends are bent into loops or hooks. After they have been cut to size, coil springs are heat treated to give them more flexibility and resilience. Believe it or not, the size of a spring ranges dramatically. The very biggest may be as thick as a broom handle, and are used as parts in locomotive wheels. The smallest are as thin as a single human hair, and are used in modern electronics. The demand for small springs is rapidly growing within the electronics industry. Cell phones and computers are calling for miniature springs that are used in touchpad keys and keyboards for a more tactile response. Medical devices also use small springs in catheters and endoscopes. Spring manufacturers are able to produce springs as small as 0.0036 inches thick, and smaller versions are on the way.
Recently, carbon nano-tubes (tube-shaped molecules made of carbon) were formed into springs able to store a great amount of energy—as much as lithium batteries! Although carbon nano-tubes have a great deal of research ahead of them before they are used as a source of energy, their potential is enormous. They could provide emergency backup power for alarm systems that could last for many years, or offer long-lasting energy for portable machines like leaf blowers and hair driers. They would allow these devices to operate without loud noise or harsh fumes, and could eliminate the need for annoying cords and small gas engines. They are much more resilient and resistant to chemicals and temperatures than batteries. These tiny organic springs have the potential to store more than a thousand times the energy of steel springs and could revolutionize stored mechanical energy as we know it.