| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a positioning device capable of maintaining a degree of vacuum at a predetermined value by eliminating a portion that is not be exposed to vacuum during use under vacuum atmosphere. <P>SOLUTION: As the positioning device, a ball plunger 10 includes: a body 11 provided with a ball receiving part 14 in the tip end; a ball 15 which is received in the ball receiving part 14 and partially protruded to the outside of the ball receiving part 14; and a coil spring 17 which is provided within the ball receiving part 14 and supports the ball 15. At the tip end side of the body 11, a pair of slits 18 are formed, which communicates the inside of the ball receiving part 14 from the tip end side to the outside and at the base end side of the body 11, a gas release hole 20 communicating with the outside from the base end side in the ball receiving part 14 is formed in a penetrating manner. <P>COPYRIGHT: (C)2013,JPO&INPIT |
