Abstract:
Due to the numerous numbers of paraplegics in Nigeria, people with this condition need a dual-purpose wheelchair in their daily activities. Thus, a dual-purpose wheelchair developed with the aim of facilitating mobility for sitting and sleeping purpose is desirable to overcome mobility challenges of the paraplegic’s patients in domestic, medical and the rehabilitation centres workspace. A linkage mechanism based dual-purpose wheelchair was designed using SolidWorks, 2015 CAD software. Documented anthropometry parameter of the 5th, 50th, 75th and the 95th percentile distribution of Nigerian paraplegics was retrieved and used in the design. The developed wheelchair was powered by a battery to convert the system from the wheelchair mode (sitting mode) to the bed mode (sleeping) and relax mode or alternatively. A toggled electric switch is used to control the electric motor coupled with the screw jack connected to the linkage mechanism to change the conversion modes of the dual purpose wheelchair from bed mode to wheelchair mode or alternatively. However, the detailed analysis of the design was done, animated and simulated prior to the Finite Element Analysis of the structural members. The prototype was developed using locally available material in order to reduce the cost of production. The performance evaluation was carried out to determine the conversion rate. Result shows the average conversion rate of the dual-purpose wheelchair from bed mode to bed mode and bed mode to wheelchair at no load is about 149.7 s and 163.6 s respectively. Also the average conversion rate from wheelchair mode to bed mode and bed mode to wheelchair when loaded is about 150.4 s and 166 s respectively. The ergonomic suitability and comfortability was determined from the computed average acceleration (ARMS), vibration dose value (VDV) and weighted acceleration value (AWRMS). The result from the Experiment shows that the average acceleration falls between the range of 0.10 m/s2 and 0.29 m/s2 and the vibration dose value (VDV) ranges between 0.01m/s1.75 and 1.35 m/s1.75 which is below the recommended daily exposure action value (EAV) and daily exposure limit (ELV) value as compared with the International Standard Organisation directive (ISO) and European. This result shows the dual-purpose wheelchair is ergonomically suitable. The weighted acceleration (𝐴𝑤𝑒𝑖𝑔ℎ𝑡𝑒𝑑) was also computed and found to be between the range of 0.01 m/s2 and 0.35 m/s2 vibration value. Result shows that the value fall in the “Not Uncomfortable” zone as compared with the perception threshold weighted acceleration of Comfort International Organisation Standard value of perception
