In this paper, we proposed a tension rod mechanism for fixing ankle rehabilitation device, which is formed of the structure tightly stretched between the patients' sitting chair and floor, and the frictional force of the both ends of it keeps the position of the device during the ankle joint stretching. Generally, physical therapists treat their patients to prevent contracture and to improve walking function, but sufficient rehabilitation therapy does not conducted demanding their labor-tasks because of increase elderly population and shortage of personnel of physical therapists. Therefore rehabilitation robots have been proposed in order to help physical therapist to treat their patients. However, since patients have to transfer their body to the rehabilitation device in order to take mechanical therapy, caregivers every time supports their transfer which cause low back pain when the person who needs ankle rehabilitation uses it. Proposed mechanism allows the device to switch the state of fix/non-fix, so that it does not require transfer assistance by caregiver. Result of experiment based on developed device, proposed system had the function to stabilize within approximately 6 mm the device position during 60 N pushing dorsiflexion stretching.
