| 摘要 |
PURPOSE:To facilitate the control of the relative position between upper and lower fixed drums, by providing an roll bearing between the upper and lower fixed drums and a rotary member and setting a fixing means which fixes both drums to an attachment stand at the center of these two drums through a hole of the rotary member. CONSTITUTION:At least a roll bearing 42 is provided between the counter faces at the outer circumference side where either one of upper and lower fixed drums 30 and 31 and a rotary member 34. Thus the size of the axial direction is reduced and made thin, and highly accurate rotation is possible. Then a through hole 54 is provided at the rotary center of the member 34. An attachment screw 56 which fixes both drums 30 and 31 to an attachment stand 57 is set at the center part of both drums through the hole 51. As a result, the drum 30 is free from any deformation. Thus the control of the relative position is simplified between the drums 30 and 31. |
