Helical spring with variable wire diameter


  • Dumitru Pop
  • Simion Haragas
  • Dorian Popa


variable wire diameter, distance between coils, rotation angle, deflection, spring stiffness, Archimedean spiral


The geometrical and functional particularities of helical springs with variable wire diameter are studied in this paper. The spring’s characteristic is determined by two factors. On one hand, by the minimum distance between two adjacent coils, for the unloaded spring, distance which decreases with increasing wire diameter. On the other hand, by the coils’ deflection, which decreases with increasing wire diameter. Consequently, the actual distance between the adjacent coils represents the difference between the two sizes. As a result, the adjacent coils will successively touch each other, depending on the actual distance between them, and the spring stiffness shall be increasing.


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