The spring is a technological marvel that is equally simple and versatile. While most people understand this practical mechanism as a coiled piece of metal that can be stretched or compressed, this is a contraption that has been developed into several iterations throughout the centuries. For example, coiled steel springs are probably what most people think of but, honestly, a wooden bow (as in “archery”) is also a kind of spring. The reason for this is that the contraption is defined as any elastic object that can be used to store mechanical energy. Indeed, the potential energy stored in a flexed bow is the same as a pinball machine plunger or a door hinge.
While the wooden bow used for hunting is one of the most primitive forms of mechanical technologies, the earliest forms of the modern coiled spring (as we know it today) came about during the 15th century. The earliest forms, of course, could have been made out of any fiber that has elastic (“stretchable”) characteristics. Modern versions, of course, are usually made out of fortified metals, making steel springs, perhaps, the most common type. Phosphor bronze, Beryllium copper, and titanium are also often used in custom spring construction.
The type of spring any particular machine or mechanism may require depends largely on restriction rather than facility. Steel springs may need to aid in the transfer of electrical current or may need to offer corrosion resistance, for example. These special characteristics are largely what drive further development of the spring mechanism because there are only so many different kinds of spring functions.
For example, there are really only four categories of steel springs. Tension springs are the most common and are generally what people think about when you mention the word “spring.” This is the mechanism that stores mechanical energy when you stretch it to its full length (as in the principle of elasticity you will find in a wooden hunting bow). The further you stretch it, the more energy you can store. Compression springs work the opposite way: storing energy as you compress the mechanism (as in a gymnast’s springboard). Torsion springs store more energy in the mechanism as you twist it (as in a mousetrap). Within these classifications there are, of course, several more sub-categories that help to more accurately describe how the mechanism works, but the principles are always the same.
These days you will probably find steel springs in more machines than you realize. Obviously, analog watches and clocks still utilize springs just as they did since they were originally devised. Trampolines, door hinges, mousetraps, vehicle suspensions, firearm and other weapon mechanisms, and many more machines and devices utilize spring technology or related principles. One of the simplest springs ever invented is still in wide use today: the rubber band. Indeed, springs are among the most practical and versatile technological advances in history and they are still evolving. In fact, there is probably no end to how springs can evolve so long as technology continues to grow as well.