Patent attributes
This extensible/contractible driving device includes a rotatable driving member configured to be rotated by drive force of a driving unit; a drive force-transmitting member connected to a leading end of the internal cylinder, configured to be driven by the rotatable driving member so as to move along a rotary shaft direction of the rotatable driving member; and an elastic member disposed in the periphery of the drive force-transmitting member, connected to the leading end of the internal cylinder, and configured to apply biasing force in the rotary shaft direction to the drive force-transmitting member. The rotatable driving member, the drive force-transmitting member, and the elastic member include an intervening member (24) stored in an inner space between external and internal cylinders, disposed in the periphery of the internal cylinder, and intervening between the internal cylinder and the external cylinder. The intervening member (24) includes a plurality of component parts (31a, 31b) having a length in a longitudinal direction of the external cylinder. One of the component parts (31a) is displaced relatively with respect to the other component part (31b) so that the intervening member (24) is opened widely outward. Accordingly, it is possible to suppress a problem of slidability caused by distortion in shape of the intervening member (24) and a problem of interference among the composing members.
