Spring (device)

A spring is a device consisting of an <a href="/facts/Elasticity_(physics)/wcJoIFg1">elastic</a> but largely rigid material (typically metal) bent or molded into a form (especially a coil) that can return into shape after being compressed or extended. Springs can <a href="/facts/Energy_storage/9GWtAPeb">store energy</a> when compressed. In everyday use, the term most often refers to <a href="/facts/Coil_spring/0vS8taq4">coil springs</a>, but there are many different spring designs. Modern springs are typically manufactured from <a href="/facts/Spring_steel/H1tVxpYQ">spring steel</a>. An example of a non-metallic spring is the <a href="/facts/Bow_(weapon)/Ch6Thysp">bow</a>, made traditionally of flexible <a href="/facts/Taxus_baccata/t63vbD6R">yew</a> wood, which when <a href="/facts/Bow_draw/7UlVEvMA">drawn</a> stores energy to propel an <a href="/facts/Arrow/B21BfJoL">arrow</a>.
When a conventional spring, without stiffness variability features, is compressed or stretched from its resting position, it exerts an opposing <a href="/facts/Force/533Q1uzq">force</a> approximately proportional to its change in length (this approximation breaks down for larger deflections). The rate or spring constant of a spring is the change in the force it exerts, divided by the change in <a href="/facts/Deflection_(engineering)/xroy2lX2">deflection</a> of the spring. That is, it is the <a href="/facts/Gradient/TsR7uukj">gradient</a> of the force versus deflection <a href="/facts/Curve/xBQ0pTBW">curve</a>. An <a href="/facts/Tension_(physics)/waNGYp3a">extension</a> or <a href="/facts/Compression_(physical)/2wwcVmM0">compression</a> spring's rate is expressed in units of force divided by distance, for example or N/m or lbf/in. A <a href="/facts/Torsion_spring/qMrn3XGM">torsion spring</a> is a spring that works by twisting; when it is twisted about its axis by an angle, it produces a <a href="/facts/Torque/KcrcvNtV">torque</a> proportional to the angle. A torsion spring's rate is in units of torque divided by angle, such as <a href="/facts/Newton_metre/1c1LhdB8">N·m</a>/<a href="/facts/Radian/Srd38Sxa">rad</a> or <a href="/facts/Ft%C2%B7lbf/eYQsElep">ft·lbf</a>/degree. The inverse of spring rate is compliance, that is: if a spring has a rate of 10 N/mm, it has a compliance of 0.1 mm/N. The stiffness (or rate) of springs in parallel is <a href="/facts/Additive_map/lyCB3yy0">additive</a>, as is the compliance of springs in series.
Springs are made from a variety of elastic materials, the most common being spring steel. Small springs can be wound from pre-hardened stock, while larger ones are made from <a href="/facts/Annealing_(metallurgy)/2AfoCE4X">annealed</a> steel and hardened after manufacture. Some <a href="/facts/Non-ferrous_metal/lY7X8rAY">non-ferrous metals</a> are also used, including <a href="/facts/Phosphor_bronze/jqIGSSFG">phosphor bronze</a> and <a href="/facts/Titanium/53ArnDoy">titanium</a> for parts requiring corrosion resistance, and low-<a href="/facts/Electrical_resistance_and_conductance/hxSt0UAj">resistance</a> <a href="/facts/Beryllium_copper/YVPmtURb">beryllium copper</a> for springs carrying <a href="/facts/Electric_current/Dc1xdnUX">electric current</a>.

Spring (device) open-in-new

Spring (device)