What Is a Spiral Torsion Spring, and How Is It Manufactured?
A concentric spiral forms during the creation of a spiral torsion spring. This mechanical device stores and releases energy by exerting rotational force. The torque available per revolution is linear for the first 360°. If the deflection exceeds 360°, the coils often ‘close out’ or come into contact with each other. This causes the torque to rise rapidly.
They provide significant torque in a short rotation. Spiral torsion springs are manufactured using flat types of steel and are best suited for operation in confined spaces. At John Evans’ Sons, we accommodate any custom specification or configuration required, including but not limited to hooks, tabs, holes, and fasteners.
Materials
Various materials, including carbon steel, stainless steel, and specialty alloys, are available for development projects or prototypes. Each metal provides the following distinct advantages:
- Carbon Steel: Widely used for engineering springs, carbon steel may require pre-galvanized coatings or additional corrosion protection.
- Stainless Steel: Stainless steel exhibits excellent heat and corrosion resistance properties and is an essential metal alloy for manufacturing spiral torsion springs.
- Specialty Alloys: Metals such as chromium alloys and cold-drawn nickel are best for applications requiring high corrosion resistance when exposed to extreme temperatures.
Spiral Torsion Spring Applications
Motion applications that require short rotation (less than 360°) use spiral torsion springs, where torque is desired but the number of rotations is less than 3 max, and most typically one rotation or less. They achieve a large amount of torque through a smaller amount of rotation than power springs, and are widely used in the following industries and applications:
- Medical Devices
- Aerospace/Defense
- Industrial
- Electric Motors
- Trucking
The mounting configuration for spiral torsion springs typically includes a 90° bent tab on the inner diameter (ID) to engage with a slot in a shaft. A 180° U-hook on the outer diameter (OD) then engages with a pin or feature inside a case or pocket at the spring installation site.
Beyond their conventional use, motor brush assemblies are a common application. Although the brush component requires a pushing force rather than torque, we adapt the springs with a long arm extension. This extension exerts a pushing force on a pivoting brush mount instead of using the typical hook that provides torque.
Advantages
Flat spiral torsion springs offer a wide range of advantages. These mechanical devices are extremely durable and long-lasting, providing good value for their cost. They are also easy to use and adjustable for use in vehicles and other applications. They are relatively small, allowing them to fit in various settings, especially those with limited space.
John Evans’ Sons leads the industry in providing custom spiral torsion springs designed for a wide range of applications. They manufacture springs using materials such as stainless steel, carbon steel, and specialty alloys to deliver significant torque with minimal rotation.
