A Prototype Body-powered Prosthetic Hand Using Self-weight for Upper Limb Amputees in Return to Work

There are amputees all over the world who have lost their hands, arms, or shoulders, either congenitally or due to industrial accidents or traffic accidents. Prosthetic hands are critical for upper limb amputees to return to work. There are two types of prosthetic hands with grasping functions: body-powered and electrically operated. Body-powered prosthetic hands rely on the residual function of the upper limb to augment the grasping function of the lost hand. This study focused on improving the operability of body-powered prosthetic hands. The operation of the developed prosthetic hand enables the user to open and close the hand using only their self-weight. Two types of prosthetic hands, one conventional and the other developed were produced for evaluation. Surface EMG potentials of the trapezius, anterior, and lateral deltoid muscles were measured to determine the amount of activity during the opening and closing of the hand. The activity of the trapezius, anterior, and lateral deltoid muscles was measured during the opening and closing of the hand. From the evaluation results, it was confirmed that the user can open and close the hand with only their self-weight.