| 摘要 |
PURPOSE:To improve centering accuracy of a disk, and also to clamp the disk safely and exactly, by holding the inside and outside circumferences of the disk by almost uniform pressure by a projected elastic film. CONSTITUTION:A turntable 1 has a cavity part 3, and also on the center part and the outside circumference part of a disk holding (placing) side, holes 4a, 4b communicating to the cavity part 3 are formed. On these hole parts, an elastic film 5 is provided so as to block each hole. A fluid injecting means 6 for injecting a fluid into the cavity part 3 stops injection of the fluid in response to an output of a pressure detecting neans 7 for detecting the pressure in the cavity part 3. The pressure detecting means 7 is constituted of, for instance, an operating piece 8 which moves up and down in accordance with a variation of internal pressure, in the cavity part 3, and a switching means 9 which is interlocked with this operating piece 8, is operated when internal pressure of the cavity part 3 has reached prescribed pressure, and generates an output. |
