Team Members: Edgar Aguilar, Alex Chung, Gianfranco Di Paolo Yorlano, Kyle Hansen, Gregory Olivas, Elmer Onofre, Sean Richard
Faculty Advisor: Scott Shaffar
QL+ Program Manager: Bob Wolff
QL+ engineering students from San Diego State University tackled the Motorcycle Wheelchair Carrier Challenge. The goal of this Challenge was to design and fabricate a carrier for a motorcycle that can securely attach a wheelchair for a paralyzed Veteran. The Challenger for this project is Tammy Landeen, a retired 10-year US Army Veteran from Caribou, Maine who became paralyzed due to a horseback riding accident 18 years ago. After intense years of physical therapy, Tammy improved her health and soon joined a disabled Veteran racing team, participated in a para-triathlon, and even has taken up horseback riding again. In addition to her athletic lifestyle, Tammy loves to ride on her husband’s motorcycle and they frequently go on long road trips together.
Because Tammy has a spinal cord injury and uses a wheelchair, her husband has the task of strapping her wheelchair to the top of a supply trailer with bungee cords. The trailer and the tied-up wheelchair are hauled with the motorcycle for 1500+ miles. It takes upwards of 30 minutes to detach and reattach the wheelchair to the trailer. To save on time and trailer space, Tammy wants an easy way to attach her wheelchair to the bike that allows for a quick disconnect and reconnect.
The idea of this project is to provide Tammy a motorcycle wheelchair carrier that would not only help her enjoy road trips with her husband but also make it easier for both of them when it comes to attaching or dismounting the wheelchair.
The carrier conforms with the client’s custom wheelchair and does not alter the structure of the wheelchair frame when secured. The product does not interfere or change the drivability or appearance of the motorcycle. The additional user requirements of the motorcycle wheelchair carrier were as follows:
• Wheelchair must stay securely on the motorcycle during high speeds and bumpy terrain
• Must be waterproof
• Must be durable
• Must not negatively affect the drivability of the motorcycle
• Must abide by all US vehicle codes and regulations
• Must detach and reattach from the bike in less than 5 minutes
• Must not interfere with the towing capabilities of the bike
• Must demonstrate structural ability with a substantial factor of safety
This was accomplished by creating an easy-attach and easy-release system that is connected to the motorcycle. The team's final Design was dubbed the Motorcycle Wheelchair Carrier or MWC. The MWC is a 1/8in thick fiberglass box that is approximately 2ft X 2ft X 3ft. The carrier was modeled to reduce drag and subsequently minimize the dynamic pressure on the system during operation. The MWC’s fiberglass is composed of modified twill and slow cure epoxy hardener and primer. This surface is then painted with automotive quality paint to match the VTX 1800 motorcycle’s finish. The fiberglass box is made of a two-piece system with one side being attached to the motorcycle and the other swinging up to 90 degrees on a hinge acting as a door.
The box is outfitted with an array of hardware that aids weatherproofing, security and reduces stresses on system components. The door feature and the fixed shell will be outfitted with an interior and exterior aluminum extrusions, and dampening foam that also interacts as a watertight system. These extrusions are bent to the box’s open edge profile and nest inside each other to form a weatherproof seal. Two stainless steel toggle latches with locking safety catches will be fastened with screws to the right side of the box to secure the two fiberglass components together. In addition, each of these latches includes a locking mechanism that will act as a failsafe during operation and act as an anti-theft device. On the left side of the box is a 16in X 4in stainless steel piano hinge with a half-inch knuckle height. This hinge was chosen because it will provide superior stress distribution when the door is in the open position.
A key decision when creating the design was the orientation of the wheelchair in our carrier. It was determined that a horizontal orientation with the wheels tucked underneath the frame would allow for the most compact load profile. This orientation is also user-friendly since it exposes the wheelchairs axle as a carrying point for loading and unloading. It also allows for the hub locking feature to be utilized by the Panthera X wheels. This feature allows for a pin to be inserted through both wheel hubs locking the wheels together. This feature allows for both wheels to be transferred to and from the carrier as a single unit and drastically increases ease of use.
The MWC interior is made large enough to support the largest configuration of the Panthera X wheelchair and still leave room for vibration dampening foam. ½in closed cell foam was selected as the dampening material due to its resistance to humidity and repetitive loading. The foam will entirely cover the interior surface and act as a secondary water sealant. Dampening foam is a crucial design element since the Panthera X frame is mostly made of carbon fiber, which tends to scratch. Their secondary vibration mitigation system is a system of D ring anchors and straps that will allow the operator to securely strap wheelchair components into the carrier. The D ring will be designed to accept multiple types of fastening elements, so a variety of straps can be used, from bungee cords to Velcro straps.