Designing a Rapid Release Ski Binding to Prevent ACL Injuries
Abstract/Contents
- Abstract
- Although modern ski bindings have significantly reduced the rate of tibia and ankle injuries, they have simultaneously increased the frequency of knee injuries. On average, over 500,000 adults are injured while skiing every year, and 30-40% of those injuries are knee injuries. In response to this alarming injury percentage, our team, in collaboration with the Department of Orthopedics at Stanford Medicine, has developed a ski binding capable of rapidly reducing loading on the knee in response to a signal from a separately developed sensor system on the knee. Our design rapidly enables lateral and rotational degrees of freedom at the heel of the boot to allow the boot to exit laterally when a signal is received from the sensor system. First, the actuator sub-assembly quickly enables the extra degrees of freedom through stored potential energy in a spring and a pull-type solenoid. These additional degrees of freedom immediately decouple the dangerous moments in the ski from the user, buying time for a controlled lateral release of the boot. Second, the mechanical boot release sub-assembly allows the heel binding to slide and pivot to allow the boot to exit. Testing of the actuator sub-assembly found that it could respond to a digital signal and enable the degrees of freedom in 41 ms or less, meeting our requirement to reduce loading on the knee within 60 ms. Additionally, testing of the mechanical boot release sub-assembly found that it took a maximum of about 14 Nm to release the boot from the binding with no increase in torque on the knee at any point during the ejection process. We were satisfied with 14 Nm because it is less than a quarter of the torque required to eject a boot from a mid-range existing binding. Finally, we integrated the two sub-assemblies for a full system test where we saw success at low loading conditions but discovered excess friction in the system at higher preloads that prevented the system from actuating successfully. We were also able to successfully integrate our system with the sensor system. Our tests concluded that the concept is viable with both sub-assembly tests confirming its ability to reduce loading on the knee within 60 ms. However, further work is needed to make the full system reliable under high preload conditions. Future steps include reducing friction in the system to improve reliability, adding weather and shock proofing, and miniaturization of components for production.
Description
| Type of resource | text |
|---|---|
| Publication date | May 6, 2024; 2024 |
Creators/Contributors
| Author | Bell, Spencer |
|---|---|
| Author | Painter, Jackson |
| Author | Stein, Renn |
| Author | Urdaneta, Sebastian |
| Advisor | Shea, Kevin |
| Advisor | Wood, Jeff |
| Advisor | Van Dalsem, Bill |
| Sponsor | Stanford Medicine Department of Orthopedics |
Subjects
| Subject | Mechanical engineering |
|---|---|
| Genre | Text |
| Genre | Report |
Bibliographic information
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- User agrees that, where applicable, content will not be used to identify or to otherwise infringe the privacy or confidentiality rights of individuals. Content distributed via the Stanford Digital Repository may be subject to additional license and use restrictions applied by the depositor.
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 4.0 International license (CC BY-NC).
Preferred citation
- Preferred citation
- Bell, S., Painter, J., Stein, R., and Urdaneta, S. (2024). Designing a Rapid Release Ski Binding to Prevent ACL Injuries. Stanford Digital Repository. Available at https://purl.stanford.edu/pd443tq7153. https://doi.org/10.25740/pd443tq7153.
Collection
ME170 Mechanical Engineering Design
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