Applications of Spiral Springs

Most spiral springs can achieve automatic reset within a certain range. For instance, when drilling with a bench drill, you hold down the feed handle to move the drill bit downward. Once drilling is complete and you release your grip, the drill bit automatically rises back to its original position, which is made possible by a spiral spring fitted inside the handle shaft. There are numerous examples of spiral springs being used for resetting in mechanical equipment, with extensive applications in various automatic machines, printing presses and packaging machines.

In addition, spiral springs are frequently utilized for balancing purposes. Take a component mounted on a vertical guide rail as an example: it needs to move up and down along the rail and stay steadily fixed at any position. The component is pulled by a chain during vertical movement. As the component moves lower, the extended length of the chain increases. Since the chain itself has weight, the total weight of the component plus the chain becomes heavier than when the component is at the top of the rail. This weight imbalance of the assembly at different vertical positions can be offset by the additional balancing force provided by a spiral spring.

A common tape measure is another typical application of spiral springs, which helps reduce overall size.

Spiral springs are not as widely used as torsion springs, mainly due to their complicated manufacturing process. They are usually produced by specialized manufacturers. Small batch orders come with high unit prices and yield little profit for manufacturers, who are therefore reluctant to accept such orders. Conversely, large batch production carries significant waste risks if the finished products fail to meet specifications, which also damages the reputation of technical designers. Furthermore, spiral springs require relatively long production lead times. For these reasons, design engineers generally avoid specifying spiral springs whenever possible. Spiral springs are only cost-effective for mass-produced products in most scenarios.