Torsion Springs

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Torsion Springs (Range of Wire 0.3mm to 16mm)

Torsion Springs are generally manufactured in two distinct varieties: Single Torsion and Double torsion, and within that there are an almost infinite number of spring leg profiles falling into three distinct categories: Radial Legs, Tangential Legs, and Axial Legs. A Torsion Spring has the distinct advantage that up to 100% of the available stress range may be utilised, whereas in Extension and Compression springs the practical limits are 50 % an=d 70% for most Carbon Steels. This can increase the range of their application, and fatigue duty. It also effectively gives rise to a greater operational range (stroke).

A Double Torsion spring has two oppositely wound helixes, usually joined together with a separating bar or “Bridge”. Due to the two opposite helixes, they are slightly more involved and time consuming to set up and manufacture. They are therefore generally more expensive initially, often requiring specialised tooling. Both Single and Double Torsion springs are used in a numerous and wide range of applications, such as counterbalancing, lever systems, latch mechanisms, working over shafts, as well as many general applications, especially in the agricultural field.

Torsion springs work by twisting the wire, or by applying a torsional moment upon the wire in a specific direction. A Torsion Spring should be designed to be operated where it will tighten the helix of the spring (causing the number of coils to increase), unwinding of the spring will cause serious distortion and failure in most cases. A Torsion Spring has a near to linear rate, but it must be considered that the spring leg will also deform when the load is applied. Noise may be generated from this design, where the spring runs on a shaft and inter-coil friction which unless a pitch separating the coils is specified, can give rise to high levels of wear. To prevent the inter-coil friction generating a noise, the coils are pitched, but this requires a larger working envelope.