| 摘要 |
PURPOSE:To prevent backlash against external vibrations in two directions as vertical and horizontal by abutting the rack slantingly against the feed screw, energizing at the same time the rack by a spring from a slant direction and giving such as energized effect to the rack in the vertical and horizontal directions against the feed screw. CONSTITUTION:A thread surface of the rack 49 is slant against a line from this thread surface of the rack 49 to a guide rail 35 on the opposite side of the rack fitted with a pickup 49 under the state of meshing the rack 49 with the feed screw 46. Backlash due to an external vibration giving horizontally to the guide rail 35 is prevented by the horizontal component force, while backlash due to the external vibration giving vertically is prevented by the vertical component force. Consequently, by abutting the rack 49 slantingly against the guide rail 35, the backlash of both horizontal and vertical directions can be prevented to allow the pickup 37 to move along.
|
