Development of Legless Chair with Seat Motion Which Follows Standing Up Action (Mechanism and Its Fundamental Motion)

Abstract

This paper deals with the legless chair with seat motion which follows standing up action from a floor for an elderly with dysfuctions of lower extremities in their home. The trial model realized its motion with the mechanism, which has been devised and acquired the patent. The chair consists of the paired four-link mechanism linked by both end fixed wire and actuator placed under the elbow rest in order to obtain uplift stroke of the seat. Pseudo two degree of freedom movement pulled ahead with forward tilting of the upper body has been effectively realized by the link mechanism with the only one actuator in principle. The largest advantage of the mechanism has the seat motion which can be easily adapted only by position adjustment of the sliding pulley without difficult adjustment of wire length for individual specificity and secular change of the old people. Characteristics of quasi-static motion and mechanics were analytically clarified with the link model for human and mechanism. Movement of the mechanism and standing up action of the human body was obtained by analysis of image captured with CCD camera. The experimental values agree approximately with the theoretical results.