Shaped Springs for Furniture
Many of the springs used in our world are used for our own comfort, such as to support sofas, chairs, and mattresses. Furniture springs have a unique shape, which is shaped somewhat like an hour glass with a larger top and bottom and a narrower middle. This shape is used so that the springs provide enough support and are easy to sew or attach to the furniture in some way. The centers of the springs are smaller so they still retain flexibility and are still easy to compress and expand.
Many furniture springs are made from steel. Steel springs provide a high level of support and strength, and are inexpensive to make. Steel springs also maintain their original shape and bounce after many years of constant use. In fact, it is rare for a steel spring to break when used inside furniture. It is more likely that the fabric surrounding the spring will break before the spring itself will have problems.
There are many different ways to make a steel spring. Some large machines can create thousands of springs in just a few minutes. Smaller spring manufacturers may use a semi-automatic spring shaper that is operated by human workers. The small spring machine is capable of winding a few springs per minute, and is used by many specialty furniture and mattress makers to create customized products.
An operator slides a steel wire into a hole in the machine. The wire is then threaded around a series of metal rollers. The spring is anchored into the machine and locked into place. The operator then presses a button in quick succession. This causes the rollers to twist and move inside the machine, twisting the spring into the desired conical shape. The machine automatically ejects the finished springs, which can then be tempered to retain their shape and prevent the springs from stretching out.