Spring Tension

Spring tension is the force or pressure exerted by a spring when it is stretched or compressed from its natural or equilibrium position.  Springs are mechanical components that store potential energy when they are deformed from their rest position and release this energy when they return to their original state.  The amount of spring tension required for a particular application depends on the desired function and the materials and design of the spring.  Springs can be designed to provide very light tension for delicate applications or heavy tension for tasks that require more force.  They come in various shapes and sizes, including coil springs, leaf springs, and torsion springs, each with its own characteristics and uses.

Spring Tension in Various Applications

Door Springs  -  The springs used in door hinges or closers provide tension to help close the door automatically.
Mattress Springs  -  In mattresses, springs are used to provide support and tension to conform to the body's shape.
Mechanical Watches  -  The balance spring in a mechanical watch provides tension to regulate the watch's timekeeping.
Automobile Suspension  -  Springs in a car's suspension system absorb shocks and provide tension to keep the wheels in contact with the road.
Exercise Equipment  -  Springs are often used in exercise equipment like resistance bands and weight machines to provide varying levels of tension for resistance training.
Pen Springs  -  The spring in a retractable pen provides tension to extend and retract the pen tip.

 

Spring Tension Formula
\( T_i \;=\;  P - n_s \cdot l_f  \)     (Spring Tension) \( P \;=\;  T_i + n_s \cdot l_f  \) \( n_s \;=\;  \dfrac{ P - T_i }{ l_f  }\) \( l_f \;=\;  \dfrac{  P - T_i }{ n_s  }\)
Symbol	English	Metric
\( T_i \) = initial tension	\( lbf \)	\( N \)
\( P \) = load	\( lbf \)	\( kg \)
\( n_s \) = spring rate	\(lbf\;/\;in\)	\(kg\;/\;mm\)
\( l_f \) = final length	\( in \)	\( mm \)