Torsion springs are the odd man out when it comes to spring design, but their unique properties make them perfect for applications that cannot operate using standard springs. When thinking about torsion spring design, manufacturers should take into account the number of total and active coils as well as the wire material, diameter and finish.
Unlike compression and extension springs, which exert forces that are parallel to the spring itself, torsion springs exert a torque (or rotary) force that rotates around the center of the spring. The ends of the spring are attached to the components, which rotate as the spring attempts to push them back into place.
What are the Most Common Uses for Torsion Springs?
Torsion springs can be found in many applications, and can work in either a clockwise or counter-clockwise manner. They are commonly found in a multitude of products like:
- Clothespins
- Watches
- Clipboards
- Ratchets
Torsion springs are also used in a variety of heavy-duty products, which include:
- Ramps
- Door hinges
- Hatches and lids
- Garage doors
- Tailgates
Their mechanical uses can also include vehicle suspensions (for larger torsion springs) and various electronic devices (for miniature torsion springs). Since torsion springs operate rotationally and do not expand, they are best suited for applications in which limited space is a large factor in product design.
Design Factors
Torsion spring design requires engineers to consider factors like spring rate, maximum deflection, maximum load and the direction of the spring wind. Torsion springs work best when load is applied in the direction of the wind, and they should never unwind from the free position.
Engineers also take into consideration the inner and outer diameter of the wire used, and the total length of the spring coil.