4 Springs for Countless Applications
by Rebekah Fuller, Editor for IQS
If you asked a kindergartener to describe a spring, I’m guessing he or she would give an answer along the lines of “it’s bouncy!”. This comes from my own experience with springs when I was that age, particularly my bed springs. It was exhilarating to see how close the coiled elasticity of those metal springs could get me to my ceiling, before their resisting force eased my landing! Of course then I didn’t understand how the mechanisms hidden within my mattress worked, including the fact that springs’ elasticity diminishes over time. I still probably wouldn’t have heeded my father’s “no jumping on the bed” order.
From micro springs used in such devices as pacemakers to gigantic ones functioning within a NASA shuttle, we are surrounded by springs our entire lives. Have you ever dissected a writing pen, particularly a “push top” one? I know I did on a number of occasions during my school days. Well, if you have, you encountered the most common type of spring – the compression spring. The bed springs talked about earlier can also be categorized as compression springs, and shock absorbers are just another of the many examples. The aptly named springs are “compressed” under a load, acting as an impact cushion by absorbing the energy of the element causing compression.
The extension spring could be looked at as the opposite of the compression spring. They are both coiled springs; however, extension springs begin tightly coiled. You could say that extension springs start out compressed, ready to be extended to maintain necessary tension or force between two objects; while compression springs start out extended and become more compressed as they resist against the load. Extension springs are configured with hooks on both ends for attachment between the two objects that need to be kept in tension.
Torsion springs are considered spiral springs because rather than the linear (pulling or pushing) force involved with the functions of the previously mentioned springs, torsion springs store and apply rotational (twisting) force/torque. A door that shuts automatically when released relies on the stored rotational energy of a torsion spring hinge. Other single and double torsion spring applications include electronics & communications equipment, sensors & switches, office equipment, electrical interconnects, acoustic equipment, hand tools, automotive & aerospace mechanisms, medical devices, etc.
Flat springs are made of strip metal instead of the commonly recognizable round spring wire that gives the majority of springs their coiled appearance. A flat spring can simply be a single strip of metal strategically curved or bent, a combination of a number of these flat spring leafs (see above), or a coil of flat strip metal (as in a tape measure). Flat layered leaf springs are most notably used in a vehicle’s suspension system to ensure stability and reduce wear on other parts.