Wheelchair Crashworthiness

1
Wheelchair Crashworthiness

• Wheelchairs
• designed to provide mobility to individuals
• not designed as automobile seats

Seat and Back Support Surfaces
Attachment Hardware
2
Crashworthiness of Seat and Back Surfaces and
Attachment Hardware
Seat Surface Test
3
W/C Back and Attachment Hardware failure
4
Sling Back Sling Seat failure
5
Drop Seat performance
Straps withstood Crash Loading
6
Drop Seat failure
7
Inserts failure
8
Attachment Hardware bending
Fracture and bending of hardware
9
Sling Back Sling Seat Performance
10
Wheelchair Seating System Hardware failure
11
Sled Test Results
Seat surface failure
Front
Rear
12
Sled Test Results
Seat attachment hardware slid along seat frame.
Shear Load
Seat Frame
Seat Attachment Hardware
13
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

14
Preliminary list of Transit Wheelchairs and Seat
Systems

• Ottobock
• Sammons-Preston
• Accufast Inc.
• Pride Health
• Snugseat
• AES
• Patron

• Contact
• Convaid
• Invacare
• Sunrise Medical
• Freedom Design
• Mulholland Positioning Systems

15
More Information

• Electronic resources
• www.RERCWTS.pitt.edu
• www.wheelchairnet.org
• Wheelchair Securement and Occupant Restraint
  training
• Qstraint
• Kinedyne Corporation/Sure-Lok
• Creative Controls
• Ortho safe systems, Inc.
• Gresham Driving Aids, Inc.
• Tie tech, Inc.

Sure-Lok
16
WHEELCHAIR TRANSPORTATION STANDARDS-Overview and
Status
March 2004 ISS-Instuctional Course

• Douglas Hobson, PhD

Department of Rehabilitation Science and
Technology University of Pittsburgh Funding
National Institute on Disability and
Rehabilitation Research Washington, DC
17
The challenge - providing safe transportation for
occupants seated in wheelchairs
18
The primary cause of serious injury in a
motor-vehicle crash is
Direct contact with vehicle structures or other
objects, due to

• 1) occupant movement inside the vehicle, or
• 2) occupant ejection from the vehicle.

19
Wheelchair transport is complicated by the
increasing variety of wheelchairs
20
most of which are not designed to be used as a
seat in a motor vehicle
21
Providing safe transportation is a
systems
problem,--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
22
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.

23
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.

24
And not to do this!
25
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

26
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-Z604Mobility devices for use in motor
  vehicles
• ISO16840-4 W/C Seating intended for use in a
  motor vehicle

27
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.

28
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

29
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

30
Frontal impact test of WTORS
Test setup using a 187-lb surrogate wheelchair
and 170-lb crash dummy
31
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 --gt 200mm
• Dummy knee --gt 375mm
• Dummy head --gt 650mm
• 3) No WC loading of occupant
• EXknee/EXwc gt 1.1

32
Part 1 General requirements and test methods for
all systems

• Installation Instructions Rear Tiedown Angles

33
Part 1 General requirements and test methods for
all systems

• Installation Pelvic Restraint Angles

34
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.

35
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