A novel four-caster manual vehicle manoeuvring investigation: Higher loading-weights require larger turning spaces

Abstract

Patient-hoists, goods-trolleys and other omni-directional manually operated vehicles are ubiquitous. Yet no substantive, empirically based dynamic analysis has been made of these four-caster vehicles despite manual handling concerns. A relationship between loading-weight and turning space is indicated by theoretical analysis which further shows that this effect is represented by only 11 different manoeuvres. A qualitative account of the theory is presented. These 11 manoeuvres were implemented experimentally. A total of 17 subjects selected a maximum comfortable loading-weight for the four-caster vehicle for each of the 11 manoeuvres. Vehicle displacement and handle forces were measured for different centres of zero velocity. The median loading-weight of the manoeuvre with the highest loading-weight selections was 101% greater than the mean loading-weight of the three manoeuvres with the lowest loading-weight selections. The manoeuvre with the highest loading-weight selections required a larger vehicle turning space: one dimension increased by 37% (173 mm) compared with the three lowest loading-weight selection manoeuvres and the other dimension increased by 17% (130 mm) compared with one of the lowest loading-weight selection manoeuvres. Higher loading-weights require larger turning spaces. These results can contribute to building designs which facilitate safe manual manoeuvring of four-caster vehicles.