| 摘要 |
PURPOSE:To enable high accurate stage movement to be performed, by providing two sets of spring members having large rigidity in the axial direction of a threaded shaft while being easily deformed in a vertical plane with respect to the threaded shaft due to the spring action. CONSTITUTION:An internal thread 12, engaging with a threaded shaft 11 rotatably supported to a bed, is secured by a screw 17a bringing protrusive parts 13 and 14, provided in the central parts of upper and bottom surfaces, into contact with the centers of thin plates 15 and 16 being a spring member. While both ends of the thin plates 15 and 16 are secured by a screw 17b to strong intermediate plates 18 and 19 placed laterally of the internal thread 12 further with a thickness larger than that of the thin plate 15 or the like. Further the intermediate plates 18 and 19, in which protrusive parts 20 and 21 provided in their central parts are brought into contact with thin plates 22 and 23 being a spring member in a thickness equal to that of the thin plate 15 or the like, are secured by a screw 17c. While the thin plates 22 and 23, being brought into contact with protrusive parts 25-28 in a stage 24 being a mover, are secured by a screw 17d. |
