Abstract: A coating apparatus for coating an outer peripheral surface of a rod-shaped workpiece with a covering material, comprising an elastic body having a covering material-impregnatable property and provided with an insertion hole through which the workpiece is to be passed, and a moving mechanism for moving the workpiece relative to the elastic body through the insertion hole, wherein the outer peripheral surface of the workpiece is coated with the covering material impregnated in the elastic body, when the workpiece is passed through the insertion hole of the elastic body by the moving mechanism.

Abstract: An apparatus for testing a tube for its strength to resist internal pressure, is composed of: an expandable elastomer having a hollow body with one open end; a test head, connected to the expandable elastomer, to provide the expandable elastomer with pressure using fluid as a medium; a holder, disposed below the test head, to vertically move a tube into a place in which the expandable elastomer is inserted into a tube; and a transferring mechanism, arranged beside the holder, to provide the holder with a tube from a rack. The apparatus according to the present invention can automatically and continuously test numerous tubes for its strength to resist internal pressure, overcoming disadvantages of the non-automatic, non-continuous apparatus previously disclosed.

Abstract: In a method of detecting defects formed in a surface or in the vicinity thereof of a ball of a bearing by means of an ultrasonic wave, the ball and a probe for projecting an ultrasonic wave toward the ball and receiving an ultrasonic wave reflected from the detects are arranged in water in such a manner that a center axis of the probe is deviated from a normal axis of the ball which passes through a center of the ball and extends in parallel with the center axis of the probe by such a displacement amount that the ultrasonic wave refracted by the ball propagates along the surface of ball. The ball is rotated about a horizontal axis perpendicular to the normal axis, and the ball and probe are rotated relative to each other about a center axis of the ball which is perpendicular both to the normal axis and horizontal axis of the ball, so that the whole surface of the ball is scanned automatically with the ultrasonic wave.