What this calculator does
A double torsion spring splits the wire into two coils that share the load, reducing the stress for the same torque and producing a symmetrical force. The calculator handles same-direction and opposite-direction winding and checks both coils and the connecting arms.
Inputs and outputs
Inputs
- Wire diameter and mean diameter
- Coils per side
- Arm length and leg angle
- Rotation angle
- Winding arrangement
- Material
Results
- Combined torque
- Rate per coil
- Bending stress in each coil
- Maximum rotation
- Arm stress and 3D preview
Typical applications
- Heavy lids and hatches
- Ratchets
- Toggle clamps
- Industrial hinges
- Door hardware
Design notes
Opposite-direction winding balances side loads but takes more space; same-direction winding is compact but produces a net axial force. State the arrangement explicitly on the drawing, together with the position of the centre arms.
The interactive calculator interface is currently in Chinese. Enter your values there, or send us the load, travel and space constraints and our engineers will return a checked calculation sheet in English.
Frequently asked questions
Why use two coils instead of one?
Two coils share the torque, so each coil sees roughly half the stress. That allows a smaller wire or a longer life in the same envelope.
What does opposite-direction winding do?
It cancels the axial force that a single coil produces when wound, so the spring stays centred and the two legs can be loaded symmetrically.
Can both legs be customised?
Yes. Leg length, leg angle and end treatment are made to the drawing, including asymmetric legs when the mechanism requires it.
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Need this spring manufactured?
Send a drawing, a sample or the parameters from this calculator. We will review manufacturability and reply with a quote and a sample lead time.