Resource
What is a double torsion spring?
Two coils, wound opposite ways, joined by a centre loop that sits over the hinge pin. Both sides of the hinge can push together.
The layout
A double torsion spring is two helical coils on one piece of wire. They are wound opposite ways so that when the legs move, both coils wind up (or both unwind) together. A centre loop joins them and usually sits over the hinge pin.
It is not two springs loosely paired. It is one part. It is also not a spiral spring, which is wound flat.
When to use it
A lid, a clamp, a switch or a fold where both sides of the pin must push. A single torsion spring on one side leaves the hinge unbalanced. Two separate torsion springs mean two part numbers and twice the chance the winds do not match.
In our unit, double torsion is the second-largest volume after single torsion. Wire Ø 0.40–2.50 mm.
What to put on the drawing
- Wire diameter and mean or outer diameter of each coil
- Coils on each side (they are often the same)
- Centre-loop width, and the shaft or pin it sits on
- Both leg lengths and shapes
- Free angle and the working angle, with torque if you have it
- Wind direction for each coil (they should be opposite)
- Material and quantity
Send the drawing or an unused sample. We quote within 24 hours.