Within the elastic limit, the elastic force of the hardware spring is proportional to the amount of spring deformation (elongation or compression value).

Writing: F=k·x

Among them: “F” represents the elastic force of the spring, which is the force applied to the force when the spring deforms.

“X” is the length of the spring that is stretched or shortened. Note that “x” is based on the length of the spring without deformation, that is, x=x’-x0 or x=x0-x’.

“K” is called the stiffness coefficient of the spring. It describes the magnitude of the elastic force generated by the unit deformation. The large value of k indicates that the force required for the deformation unit is large, or the spring is “hard”.

k is related to spring material, length, thickness, etc. The international unit of k is cattle/meter.

If several identical springs are connected in series or in parallel, the stiffness coefficient of this new spring is no longer the original stiffness coefficient.

Assuming that the stiffness coefficient of two springs with both stiffness coefficients k in series is k1, then F=k1·x. Since the elastic force at point a is also F, the two stiffness coefficients can be written for spring 1. When the springs with the same original length of k are connected in parallel, the stiffness coefficient is k2, then the number of F=k2·x becomes smaller, and the one after parallel connection becomes larger.