Patent attributes
A technique and apparatus for effectively constructing a cover for covering a vehicle airbag is provided. An ultrasonic machine is used that includes an ultrasonic machining blade for machining a tear line in the cover rear surface of the airbag cover. First and second transmitting displacement sensors are disposed on the opposite side of the cover rear surface of the airbag cover so as to be opposed to a cutting edge of the ultrasonic machining blade with the airbag cover interposed therebetween. The sensors directly sense the distance between the cutting edge of the machining blade and each of the first and second displacement sensors and through the airbag cover. A control section controls the relative position of the cutting edge with respect to the airbag cover, based on the sensed results by the first and second displacement sensors.
