Design and material selection for a patient transport device in field hospitals

Abstract

ACKGROUND: A major cause of patient and hospital worker injuries occurs transferring patients between two planes. The main aim of this paper was to propose a design of patient’s lift and transfer apparatus for use in field hospitals. The assumption was to design lightweight, durable and ergonomic device using innovative material. The authors concentrated on partial elimination of manual lifting in order to device could work both in two situations: with or without electricity. The paper includes mechanical design, material selection and analytical calculation. METHODS: In order to carry out strength calculations, the shape and size of device was designed using AutoCAD. Based on a comparison of composite material properties, an epoxy-carbon laminate was selected. The strength calculations were performed in the following order: determination of elementary stresses, determination of the most dangerous cross-section, calculation of tensile strength, calculation of Young’s modulus, selection of channel dimensions, determination of material parameters (thickness, fiber mass), determination of substitute stresses. RESULTS: To design a lightweight, durable and ergonomic patient lift with lifting capacity of 150 kg an epoxy-carbon laminate composed of three layers was chosen. A profile in a C-shape and dimension of 138x90x14 mm has been designed. Patient lift includes an arm of 1.6 m height and 1m length of the horizontal beam. The designed transport mechanism uses rollers, a linear electric actuator and a crank with a worm gear. CONCLUSIONS: The designed device fulfil the most important criterion, which is to ensure the safety of patients and medical personnel. The height adjustment mechanism partially eliminates the manual transfer of patients and is adapted to the conditions existing in a field hospital.