Constant force springs (or constant torque springs) are named as such because their motion force is continually applied. They are used in applications that require a constant load.

The spatial requirements of the spring itself are minimal, allowing for a smooth range of motion. Due to the absence of inertia to overcome, constant force springs are very versatile and can be mounted onto existing hardware, producing a balancing effect. Constant force springs are widely used in the healthcare industry to improve surgical equipment. They are also frequently used in aviation to deploy and retract aircraft doors and effectively balance aircraft windows. Of course, you will also find constant force springs in many everyday applications such as door closers, hair dryers, fitness equipment, motors, cabinet furniture components, and more.

The load of a constant force spring is determined by the width and thickness of the material as well as the diameter of the coil. Tightly wound to operate in a linear motion, they do not adhere to Hooke’s law (F=kX) but continuously generate force during their deflection. These springs provide a smooth range of motion and a constant load when extended or retracted. Constant force springs can be installed in various ways and can be partially or fully extended, and due to the lack of restrictions on extension speed and acceleration, they can be utilized in a range of applications.