| 摘要 |
PURPOSE:To make precise measurement possible in case of measurement of the shape of an article such as out of roundness or the like, by jetting compressed air uniformly from a jetting member consisting of a porous material and fitting an object to be measured to this jetting member with a narrow gap between them to hold the objet to be measured in the stable state. CONSTITUTION:Compressed air is supplied to an air chamber 11 provided in a supporting plate 7, which is supported freely rotatably on a base plate 10 through a thrust bearing 9, through an air path 12. Compressed air is jetted uniformly from the outside face of a part projected from the supporting plate 7. The outside diameter of a jetting member 8 is so determined that the inside diameter of a cylindrical object 1 to be measured whose center should be obtained is slightly larger than the outside diameter of the jetting member 8 and the object 1 to be measured can be fitted easily to the jetting member 8. Even if the gap between the inside circumferential face of the object 1 to be measured and the outside circumferential face of the jetting member 8 is not uniform, this ununiformity is corrected immediately, and the width of the gap is made uniform throughout the circumference. Thus, the center of the object 1 to be measured coincides with the center of the jetting member 8. |
