Evaluation of Wheelchair Sling Seat and Sling Back Crashworthiness

DongRan Ha, MS and G. Bertocci, PhD

Injury Risk Assessment and Prevention Laboratory
Department of Rehabilitation Science and Technology
University of Pittsburgh, Pittsburgh, PA

Slide 1
Evaluation of Wheelchair Sling Seat and Sling Back Crashworthiness

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DongRan Ha, MS and G. Bertocci, PhD

Injury Risk Assessment and Prevention Laboratory
Department of Rehabilitation Science and Technology
University of Pittsburgh, Pittsburgh, PA

Slide 2
Funded by

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PVA, CDC-CIRCL, NIDRR RERC on Wheeled Mobility

Slide 3
Background

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Many wheelchair users remain in their wheelchairs and using them as vehicle seats while they travel.

WC seats, backs, components, and frame structures may not be able to withstand the loads that can occur during crashes

Slide 4
Statement of the Problem

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ANSI/RESNA WC/19 – Wheelchairs Used as Seats in Motor Vehicles

- Sled impact testing of a complete wheelchairs

- 20g/48kph (30mph) frontal crash

Substitute or replaced seating systems will not be sled tested by ANSI/RESNA WC/19.

Slide 5
This study

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Applies the developed static test method to evaluate two specimens of three unique sling backs and three unique sling seats

- E&J P2 Plus, Invacare 9000XT, and Sunrise Medical Quickie Breezy

Slide 6
Research Question

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Do commercially available wheelchair sling seats and sling backs withstand loads that may be encountered in a motor vehicle crash?

Slide 7
Development of Test Criteria Loads

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Sling Backs:

Rear impact:

  • FMVSS 207 test criterion with consideration of occupant’s weight and inertia effects
  • 20 x (weight of the upper torso of a 50th percentile male + weight of each wheelchair seat back)
  • Approximately 2280 lb.

Rebound associated with frontal impact:

  • 20g/30mph frontal impact computer crash simulation
  • Approximately 2290 lb.

Slide 8
Development of Test Criteria Loads

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Sling Seats:

Loads determined from a computer crash simulation study done by Bertocci et al.

  • 50th percentile male Hybrid III test dummy
  • 20g/30mph frontal impact

Approximately 3750 lb

Slide 9
To successfully meet test criteria

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Sling backs are required to withstand a 2290 lb load.

Sling seats are required to withstand a 3750 lb load.

Both sling seats and sling backs must be able to withstand the test load for 5 seconds.

Slide 10
Test Set Up

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Results - Sling Back

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Graphic description: The load versus deflection curve of two specimens of E&J P2 Plus sling backs show on the top graph. And the load versus deflection curve of two specimens of Invacare 9000XT sling backs show on the bottom graph. Two specimens of each type of sling back showed similar load versus deflection characteristics.

Slide 13
Results - Sling Seat

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Graphic description:

Slide 14

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Graphic description: The load versus deflection curve of two specimens of Quickie sling seats show on the top graph. And the load versus deflection curve of two specimens of Invacare 9000XT sling seats show on the bottom graph. Two specimens of Quickie sling seat showed similar load versus deflection characteristics. The 2nd specimen of 9000XT sling seat failed at the force between 3500 lb and 4000 lb. The failure is indicated with ‘X’ mark.

Slide 15
Conclusions

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Two specimens of three sling backs and three sling seats were evaluated.

All, but two sling back specimens and two sling seat specimens, withstood the test criterion load.

Failure occurred at upholstery seams and the seat reinforcement bar.

  • Manufacturers should consider reinforcing or strengthening stitch patterns when sling upholsteries are intended for use in transport.

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Tested Products - Back

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Graphic description:

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Tested Products - Seat

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Graphic description:

Slide 18
Tested Products - Attachment Hardware

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Slide 19
Publications

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Bertocci, G., Ha, D., Deemer, E., & Karg, P. (2001). Evaluation of Wheelchair Seating Crashworthiness: "Drop Hook"- Type Seat Attachment Hardware. Archives of Physical Medicine and Rehabilitation, 82, 534-540.

Bertocci, G., Ha, D., van Roosmalen, L., Karg, P., & Deemer, E. (2000). Evaluation of Wheelchair Drop Seat Crashworthiness. Accepted in Medical Engineering & Physics.

Ha, D., Bertocci, G., Deemer, E., van Roosmalen, L., & Karg, p. (2000). Evaluation of Wheelchair Seating System Crashworthiness: Combination Wheelchair Seat Back Surfaces and Attachment Hardware. Journal of Rehab Research and Development, 37 (No. 5), 555-563.

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Thank You for Your Attention

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Return to Slide Series

Updated: March 8, 2002

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No quotes from the materials contained herein may be used in any media without attribution to WheelchairNet and the Department of Rehabilitation Science and Technology.


Please note: This information is provided a archival information from the Rehabilitation Engineering Research Center on Wheeled Mobility from 1993 to 2002.

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