The National Academies

Transit IDEA J-04/IDEA 07 [Completed (IDEA)]

Wheelchair Restraint System, Baylor College of Medicine
[ TCRP J-04 (Innovations Deserving Exploratory Analysis--The Transit IDEA Program) ]

  Project Data
Staff Responsibility: Harvey Berlin

This IDEA project produced an innovative modular wheelchair restraint system that uses pneumatically driven resilient bristles that engage the wheels and frame of a wheelchair. The system stabilizes movements during acceleration and braking, thereby reducing the risk of injury in collisions. By engaging the bristles with the wheelchair frame and wheels, it is feasible to hold a variety of wheelchair geometries without subjecting the wheelchair to significant sideward loading. The bristles are actuated by a compressor on the vehicle. There is also a vacuum line to accelerate disengagement of the bristles from the chair. The restraint also stows itself with minimum space requirement. The pneumatic operation permits quick release and evacuation in case of a power failure after a collision. The restraint design incorporates sensors that detect when the resilient bristles contact the side of the chair and acts to limit the subsequent travel of the bristles, so the chair will not collapse or bend.
The restraint protocol uses a double-staged activation to engage the bristles with the wheelchair. The first stage of activation extends the bristles in preparation for contact with the wheelchair frame, and the second stage of activation moves each section of the resilient bristles forward to engage the chair. During the second stage of activation, the bristles slide and flex freely when engaging the wheelchair frame and wheels. Any bristle placing a sideward force on the chair is retracted while other bristles continue to advance and further engage the chair. Essentially, the bristles restrain the wheelchair by making a custom mold of the frame that maximizes the area available to restrain the chair, as shown in Figures 1 and 2. In this way, stresses on the wheelchair are kept as low as possible. The excursion of the wheelchair is designed to be limited to less than 1.5 cm (0.59 in.) when loaded to the design load of 26,700 N (6,000 lbs). This design criterion conforms to standards of comfort and safety for wheelchair users.
The wheelchair restraint prototype has been constructed, and preliminary contacts have been made with manufacturers of wheelchairs and wheelchair restraints to identify partners in the commercialization of the product. In addition to increased safety for the wheelchair user, the design of the restraint system reduces ingress and egress times for wheelchairs, resulting in considerable time savings for all passengers. The engagement operation is fully automatic. Dynamic operational testing will be needed to develop a preproduction design for marketing the product

The final report for this IDEA project can be found at:

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