A shift register is used for outputting an output pulse at output end in response to a delay of an input pulse received at an input end. A plurality of pin holes are placed on the socket to provide the insert function for the pins of a IC package. The state element is used to hold the output stage at a stored value responsive to a clock signal. Each member is arranged concentrically on a plane that is perpendicular to the device axis, so that a planetary gear device that is extremely slim in the device axial direction can be realized. An assembly securing device for the vacant actuating arm, which has not yet been fitted with a flap, includes a braking device which limits the opening speed of the vacant actuating arm. The first capacitor includes a terminal connected to the second power source, and another terminal connected to a node of the first power source and a second terminal of the third switch.