Patent ID: 7798036

Claim:
A joint driving device comprising: a first configuration member; a second configuration member which is coupled to the first configuration member through a rotational joint and is relatively movable with respect to the first configuration member; a first elastic body actuator, one end portion of which is secured to the first configuration member and the other end portion of which is secured at to the second configuration member; a second elastic body actuator, one end portion of which is secured to the first configuration member and the other end portion of which is secured to the second configuration member, such that a position at which the other end portion of the second elastic body actuator is secured to the second configuration member and a position at which the other end portion of the first elastic body actuator is secured to the second configuration member are substantially symmetric about the rotational joint; and a securing-position variable mechanism for changing an interval between a position of the first elastic body actuator which is secured to the second configuration member and a position of the second elastic body actuator which is secured to the second configuration member, wherein the securing-position variable mechanism comprises: a securing-position guide mechanism for respectively guiding the secured position of the first elastic body actuator and the secured position of the second elastic body actuator in a direction perpendicular to a longitudinal direction of the second configuration member; and a securing-position moving cam mechanism for respectively moving the secured position of the first elastic body actuator and the secured position of the second elastic body actuator, while guiding them with the securing-position guide mechanism, to change the interval between the secured position of the first elastic body actuator and the secured position of the second elastic body actuator.