1. Wheelchair Crashworthiness
Wheelchairs:
designed to provide mobility to individuals
not designed as automobile seats
Seat and Back Support Surfaces
Attachment Hardware
Wheelchairs are designed to provide mobility to individuals and not designed as automobile seats,
so, in many cases, the level of protection that wheelchair and its seating systems can provide under impact is unknown.
WCSSs are often provided as add on or replacement products after the wheelchair has been in the field, so they will not be sled tested by the ANSI/RESNA WC/19 standard.
Therefore, as part of wheelchair transportation safety researches, crashworthiness of wheelchair seating systems have been also evaluated.

2. Crashworthiness of Seat and Back Surfaces and Attachment Hardware
This shows the actual test of one of the seating system static test.
Seat Surface Test

3. W/C Back and Attachment Hardware failure
These graphics show that all wheelchair back surfaces with attachment hardware failed to sustain the crash load during static test because of attachment hardware failure.
Attachment hardware bent severely, the drop hook type hardware was flattened, and the pin shaped lower hardware was released from the retention slots.

4. Sling Back & Sling Seat failure
These graphics show that only few sling seats and sling back surfaces failed.

5. Drop Seat performance Straps withstood Crash Loading
These pictures show that most drop seats failed due to deformation of drop hooks. Webbing strap type drop seats withstood crash loading.
Straps withstood Crash Loading

6. Drop Seat failure
These pictures show that most drop seats failed due to deformation of drop hooks. Webbing strap type drop seats withstood crash loading.

7. Inserts failure
These graphics show that most of the seat and back surface inserts failed at the points where the surrogate attachment hardware was attached.

8. Attachment Hardware bending
These pictures show failure of attachment hardware.
Fracture and bending of hardware

9. Sling Back & Sling Seat Performance
This shows the actual sled test of WCSSs that performed well during the test.

10. Wheelchair Seating System Hardware failure
And this clip shows the sled test of WCSSs which failed.

11. Sled Test Results Seat surface failure Front Rear
The results of sled testing showed similar failure modes to the results of static testing.
As these pictures show, the seat surface where the attachment hardware was attached failed, and straightening of drop hooks was observed during both tests.
Rear

12. Sled Test Results Seat attachment hardware slid along seat frame.
Shear Load
Also in a static test, only a downward force was applied to each wheelchair seat. However, the failure mode observed in a sled test of one wheelchair seat was result of shear loads applied to the seat.
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
We have some recommendations for the wheelchair seating system manufacturers, based on our study.
We recommend to improve strength and design of drop hook type attachment hardware,
To reinforce seat and back inserts at hardware attachment points to reduce stress concentration,
To reinforce seat and back surfaces at areas where hardware is attached,
To consider forward load while designing WC back, and finally
To 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
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

16. WHEELCHAIR TRANSPORTATION STANDARDS-Overview and Status
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

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. the vehicle (regulated by FMVSS) *the seat (i.e, wheelchair)
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.
WTORS: Wheelchair Tiedown and Occupant Restraint Systems

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!
20 minutes later---

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
ISO 10542, Parts 1&2 are 95% complete, and proceeding through the ISO fial approval process (as of 10/98).
ISO CD Wheelchairs is the standard that is concerned about the transport safety of the wheelchair itself.

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-Z604:Mobility devices for use in motor vehicles
ISO : 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
Testing of the wheelchair tiedown devices involves a simulated ( impact sled) crash test using a surrogate (simulated standard) wheelchair with a mass of 185 lbs. In the suurogate wheelchair seat is placed an anthropometric test dummy ( ATD) with a mass distribution representing that of the average male, 75kg(168lbs). The secured wheelchair and restrained ATD is then subjected to a 20g, 48kph (30mph) simulated crash.

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 --> 200mm
Dummy knee --> 375mm
Dummy head --> 650mm
3) No WC loading of occupant
EXknee/EXwc > 1.1
After the dynamic test, the above three conditions must be met for a WTORS to pass the test.
1) First, there can be no obvious structural failure of the WTORS
2) During the test, the maximum excursions of the surrogate W/c, ATD’s knee and ATD’s head cannot exceed the values shown above, and
3) The back of the surrogate W/c cannot itself apply a load on the ATD, which is verified by applying the above simply formula.

32. Part 1: General requirements and test methods for all systems
Installation Instructions: Rear Tiedown Angles
This diagram specifies the ranges of rear tiedown strap angles that should be maintained to get optimum crash protection

33. Part 1: General requirements and test methods for all systems
Installation: Pelvic Restraint Angles
This diagram specifies the ranges of pelvic restraint belt angles that should be maintained to get optimum crash protection

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