Patent ID: 7555969

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 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 is constructed so that the first elastic body actuator and the second elastic body actuator are attached to the second configuration member so as to perform relative rotation and perform relative translational motion for changing the interval between the position of the first elastic body actuator and the position of the second elastic body actuator, wherein the relative translation motion is carried out approximately along a straight line passing through an axis of the rotational joint at which the first configuration member and the second configuration member are coupled to each other so as to change the interval, and wherein the other end portions of the first and second elastic body actuators are received in elongated openings, respectively, and the relative translation motion is carried out by moving the other end portions along the elongated openings so as to change the interval.