Evaluation of wheelchair seating system crashworthiness: "Drop hook"-type seat attachment hardware

Objective: To evaluate the crashworthiness of commercially available hardwa re that attaches seat surfaces to the wheelchair frame. Design: A low cost static crashworthiness test procedure that simulates a f rontal impact motor vehicle crash. Setting: Safety testing laboratory. Specimens: Eleven unique sets of drop-hook hardware made of carbon steel (4 ), stainless steel (4), and aluminum (3). Interventions: Replicated seat-loading conditions associated with a 20g/48k ph frontal impact. Test criterion for seat loading was 16,680N (3750lb). Main Outcome Measures: Failure load and deflection of seat surface. Results: None of the hardware sets tested met the crashworthiness test crit erion. All failed at less than 50% of the load that seating hardware could be exposed to in a 20g/48kph frontal impact. The primary failure mode was e xcessive deformation, leading to an unstable seat support surface. Conclusions: Results suggest that commercially available seating drop hooks may be unable to withstand loading associated with a frontal crash and may not be the best option for use with transport wheelchairs.