Usability Based Redesign and Evaluation of Alternative Controls of Single Needle Lockstitch Machine for Lower Limb Disabilities

Abstract

The study investigates how the existed single needle lock stich machine (SNLS) can be redesigned to support individuals with lower limb disabilities. Traditional sewing machines rely on foot pedals which excludes lower limb disabilities to overcome this challenge two alternative control mechanisms were developed a hand press lever and a knob rotating cable system. By using the Quality function deployment (QFD) user needs were translated into engineering requirements guiding the design and fabrication of prototypes. Ten participants including 5 with lower limb disabilities and 5 non-disabilities tested the prototype machines and usability was measured through the system usability scale (SUS) and task completion times. Overall the results showed that both mechanisms improved accessibility for the disabilities. The hand press mechanism scored 76.5 % SUS with an average task time of 22.74 seconds while the knob rotating mechanism scored 84.5 % SUS and reduced task time to 12.78 seconds. These findings show that low cost modifications can transform sewing machine into inclusive and user friendly tools enabling people with disabilities to take part in tailoring and garment production.