Affiliations: [a] Biomedical Engineering Services, Royal Hospital for Neuro-disability, West Hill, Putney, London SW15 3SW, UK. Tel.: +44 208 780 4500, Ext. 5055; Fax: +44 208 780 4501; E-mail: scousins@rhn.org.uk | [b] Special Seating Technician, Royal Hospital for Neuro-disability, West Hill, Putney, London SW15 3SW, UK
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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 draw) 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.
