Authors:
Dr. Steve Cousins
Head of Biomedical Engineering Services
Royal Hospital for Neuro-disability
West Hill, Putney, London SW15 3SW
Telephone: 020 8780 4500 Extension 5055
Email: scousins@rhn.org.uk
Ron Clarke
Special Seating Technician
Royal Hospital for Neuro-disability
West Hill, Putney, London SW15 3SW
Telephone: 020 8780 4500 Extension 5056
Email: rclarke@rhn.org.uk
This paper has been submitted to the Journal of Disability and Technology
Abstract:
"Over the past 20 years nearly 30,000 Matrix seating systems have been fitted worldwide. After analysis of manufacturing and clinical issues, improvements to the basic Matrix elements were proposed four years ago at the Royal Hospital for Neuro-disability. A stronger, thinner, and lighter Matrix was developed with preliminary clinical evaluation started. Static and dynamic structural tests are reported. The static tests include, (1) 250 load-deflection tests of various Matrix clamp designs, and (2) load degradation tests after re-clamping for clinical shape adjustments. The dynamic, accelerated five-year life tests include, (1) fatigue tests over 500,000 cycles (comparisons to the new standard, ISO/DIS 16840-3, are drawn) and (2) 75 Kg and 34 Kg full size manikin tests in a wheelchair test carousel for 16,125 revolutions or 336 Km. Evaluations are limited to 35 patients over a maximum of 36 months with the focus on ease of use and production speed. Application to the manufacture of a custom formable removable wheelchair back is also discussed."
Table 2: Matrix Wheelchair Tilt Tests and Five-Year Life Tests
| Tilt Tests | Dynamic Tests | ||||||
|---|---|---|---|---|---|---|---|
| Rear | Front | Side | Distance | Cycles | Time | Curb Drops | |
| Manikin | (Degrees) | (Degrees) | (Degrees) | (Km) | (1 rev.) | (Hrs) | (15 cm) |
| 34 (Kg) | 18 (16) | 25 (16) | 21 (16) | 336 | 16,125 | 69 | 747 |
[Tilt Test angles are in brackets for the respective test limits.]
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