Novel Helical Spring Contact for Low Force & Fine Pitch Applications

The demand for increasing numbers of electrical contacts within the same connector footprint continues to drive contact pitches below 1mm and normal forces below 25 grams. The size reduction of contacts needed to keep pace with miniaturization is approaching the limits of traditional stamping and forming manufacturing processes. This work investigates the formation and properties of a novel spring contact produced from a pre-formed 51mm diameter wire. The resulting double helical contact springs provide a normal force of ~25 grams at a 0.25 mm compression, an elastic working range of 0.23mm, and stable electrical performance at ~5 grams force. Prototype sockets validated the functionality of the helical contacts in a fine pitch array, and demonstrated the potential for pitches down to 0.65 mm.