| 摘要 |
PURPOSE:To make possible the maintenance of interelectrode spacing at high accuracy by holding an electrode by the oscillating member sandwiching the inside and outside peripheral surfaces of the end protruding part of a rotator with two bearings and mounting the both bearings with a change of mutually 180 deg. in phase of their maximum eccentric positions. CONSTITUTION:An oscillating part 7 is provided in the form of sandwiching the inside and outside peripheral surfaces of the protruding part 17 of the end part of a rotator 2 and a recording electrode 4 is fixed thereto. The oscillating part 7 is divided to two chambers, upper and lower and an upper bearing 12 is pressed to the outside peripheral surface of the rotator 2 by a spring 10 via piston 9. Similarly, a lower bearing 16 is pressed to the inside peripheral surface. Here, the two bearings are disposed with their maximum eccentric point positions being changed mutually by 180 deg. in phase at the contact points of the protrusion part 17 and their diameters are so set as to provide the same number of revolutions. As a result of this, even if there is eccentricity in the bearings 12, 16, the position of the center of oscillation does not change and the spacing d between the rotator 2 and electrode 4 may be maintained always constant. |
