Patent ID: 7104151

Claim:
An actuator for actuating at least two driven shafts arranged in parallel with each other in axial directions thereof, through cams held on the driven shafts for driving the driven shafts respectively, so that each driven shaft is selectively moved in the axial direction thereof by a predetermined stroke by driving each cam to a predetermined stopping position in accordance with a mode changed over from another mode among a plurality of modes to be switched, the actuator comprising: a motor; a driving gear meshed with a worm formed on a shaft of the motor; an output shaft connected to the driving gear; a pair of cam followers turning by a rotation of the output shaft, and engaged with the cams so as to drive the cams; a plurality of urging members respectively held in a plurality of urging member housings formed at predetermined intervals along a circle on a side face of the driving gear; a rotation retaining plate fixed on the output shaft so as not to rotate relative to the output shaft; a plurality of pressing parts each of which projects from the rotation retaining plate, and each of which is capable of pressing one of both end portions of the corresponding urging member; slits formed on the driving gear between adjacent ones of the urging member housings so as to prevent the pressing parts from interfering with the driving gear; a first actuator case in which the driving gear, the rotation retaining plate and the output shaft are housed; and a second actuator case fixed to the first actuator case, supporting each driven shaft so that the driven shafts are moved freely in the axial direction thereof and housing each of the cams therein, wherein a rotation of the driving gear is transmitted to the output shaft via the urging members and the rotation retaining plate, either one of both end portions of each of the urging members being pressed by the corresponding pressing part of the rotation retaining plate when the rotation of the driving gear is continued after the output shaft is locked and stopped in an intermediate position of the rotation thereof.