Personnel in mobile vehicles and on vehicles may be affected by high-acceleration environments, such as collisions or rapid changes in speed, which can lead to rapid relative movement between the vehicle and passengers. Due to contact with the structure of the vehicle or equipment, these environments pose a risk of injury and the risk of being ejected from the vehicle unexpectedly. The risk of injury is particularly evident for personnel who cannot be restrained in a typical seating restraint system due to mobility requirements, such as crew members in the cargo hold of military helicopters.

Currently, systems used to restrain helicopter maneuvering crew members include gunner’s belts with fixed-length tethers or reel systems. The drawback of gunner’s belts with fixed-length tethers is that users can freely swing at any point within the tether’s range. Some tethers have non-adjustable lengths; and some tethers must be continuously manually adjusted by the user, interrupting critical mission tasks.

The reel system addresses some of the deficiencies of fixed-length tether systems by using a retractable reel that occupies the slack between the user and the reel. An acceleration-sensing reel locking mechanism can lock the reel to prevent the user or crew member from moving further in the event of high-acceleration situations.

The implementation uses a torsion spring as the main mechanism. The torsion spring is designed to provide a smaller torque range throughout the entire motion process compared to typical coil springs. The smaller torque range necessitates less force to resist the webbing’s extraction and achieve the tether’s retraction, while the applied torque is not so great as to fatigue the user.

Most power springs are produced by tightly winding the spring material around a mandrel and connecting the free end to a housing. The natural tendency of the spring to expand provides momentum to the mandrel or housing, thus generating usable torque. The total torque generated increases as the spring is wound tighter and decreases as the spring is released.

Power springs might be an attractive device to consider for your applications, as their compact size and simple design help make them relatively worry-free in applications. The material, size, and options combinations of power springs make them an appealing consideration to meet your rotational needs.