Wheelchair Crashworthiness • Wheelchairs: • designed to provide mobility to individuals • not designed as automobile seats Seat and Back Support Surfaces Attachment Hardware
Crashworthiness of Seat and Back Surfaces and Attachment Hardware Seat Surface Test
Drop Seat performance Straps withstood Crash Loading
Attachment Hardware bending Fracture and bending of hardware
Sled Test Results Seat surface failure Front Rear
Sled Test Results Seat attachment hardware slid along seat frame. Shear Load Seat Frame Seat Attachment Hardware
Recommendations • Improve strength/design of drop hook type hardware • Reinforce seat/back inserts at hardware attachment points to reduce stress concentration • Reinforcement of seat/back surfaces at areas where hardware is attached • Consider forward load while designing WC back • Consider shear load while designing WC seat
Contact: Convaid Invacare Sunrise Medical Freedom Design Mulholland Positioning Systems Ottobock Sammons-Preston Accufast Inc. Pride Health Snugseat AES Patron Preliminary list of Transit Wheelchairs and Seat Systems
More Information • Electronic resources • www.RERCWTS.pitt.edu • www.wheelchairnet.org • Wheelchair Securement and Occupant Restraint training: • Q’straint • Kinedyne Corporation/Sure-Lok • Creative Controls • Ortho safe systems, Inc. • Gresham Driving Aids, Inc. • Tie tech, Inc. Sure-Lok
March 2004 ISS-Instuctional Course WHEELCHAIR TRANSPORTATION STANDARDS-Overview and Status Douglas Hobson, PhD Department of Rehabilitation Science and Technology University of Pittsburgh Funding: National Institute on Disability and Rehabilitation Research Washington, DC
The challenge - providing safe transportation for occupants seated in wheelchairs
The primary cause of serious injury in a motor-vehicle crash is: 1) occupant movement inside the vehicle, or 2) occupant ejection from the vehicle. Direct contact with vehicle structures or other objects, due to:
“Wheelchair transport” is complicated by the increasing variety of wheelchairs
Providing safe transportation is a systemsproblem,--where the systems include: • the vehicle (regulated by FMVSS) • *the seat (i.e, wheelchair) • *the seat securement (i.e., the wheelchair tiedown) • *the occupant restraint (i.e., a 3-point belt) • the occupant (e.g., size, weight, posture, disabilities) * Focus of industry standards development
Why Standards?? The purpose is to provide: • a benchmark tests for equipment performance, • repeatable testing methods, • compatibility between system components, • installation and operational information for equipment usage, • comparable information in manuf's literature, • more independent use of transit-safety equipment.
It is not the purpose of voluntary standards to: • provide a comparable level of injury risk to wheelchair-seated travelers, or to • require or regulate the use of transit-option wheelchairs and WTORS in the real world.
Current ISO Work Program • ISO10542 WTORS* Stds. • *Part 1- General requirements and test methods (issued) • *Part 2- Four-Point Strap-Type Systems (issued) • Part 3- Docking Devices (FDIS stage) • Part 4- Clamping Devices (FDIS stage) • Part 5- Systems for Specific W/cs (FDIS stage) • NA National Equivalents: • *US-SAE-J2249: W/C Tiedown and Occupant Restraint Systems • * Can.-CSA-Z605: Mobility Securement and Occupant Restraint Systems (MSORS) * WTORS: Wheelchair tiedown and occupant restraint systems
Current ISO Work Program (cont.) • ISO7176/19 Wheelchairs: Wheelchairs used as seats in motor vehicles • N-A National Equivalents: • US-ANSI/RESNA-WC-19: Wheelchairs for use as seats in motor vehicles • Can-CSA-Z604:Mobility devices for use in motor vehicles • ISO16840-4: W/C Seating intended for use in a motor vehicle
ISO-10542: WTORS-all General: • Voluntary standards, • Intended to reduce potential for injury to W/c-seated occupants in a frontal crash, • Specifies design/ performance req'ments, test procedures, installation instructions and information disclosure requirements, • Provides test methods to verify compliance design/performance requirements.
Part 1: General requirements and test methods for all systems Scope: • Adult passengers or drivers(US/Can -child) • Public or private vehicles • Forward facing orientation only • Requires pelvic & shoulder belt restraints • Applicable to all W/Cs, including scooters • Requires dynamic testing of the WTORS • Requires labeling and user instructions • Requires disclosure of information
Part 1: General requirements and test methods for all systems • Part1-Testing: • Dynamic testing • Sled impact test • Utilizes surrogate (reusable) WC • 20 G, 30 mph deceleration pulse • 50th percentile male hybrid III ATD • Other testing • Partial engagement of components • Belt length and webbing slippage
Frontal impact test of WTORS Test setup: using a 187-lb surrogate wheelchair and 170-lb crash dummy
Part 1: General requirements and test methods for all systems Part 1- Evaluation of Test Results 1) Failure of components 2) WC & dummy excursions • Surrogate WC --> 200mm • Dummy knee --> 375mm • Dummy head --> 650mm 3) No WC loading of occupant • EXknee/EXwc > 1.1
Part 1: General requirements and test methods for all systems Installation Instructions: Rear Tiedown Angles
ISO 7176/19: Wheeled mobility devices for use as seats in motor vehicles • Main Issues: • Most w/cs not designed to withstand crash loads, • Difficult or impossible to find suitable location to attach tiedown straps, • Difficult or impossible to obtain a ‘good’ fit of the occupant restraint belts, • Side-facing orientation in vehicle may still be common practice in some locals.
Belt restraints are often placed over the soft and easily injured abdomens of wheelchair-seated occupants • Ex. of side-facing orientation • Note location of lap and chest belts