| 摘要 |
<p>A pivot (3) is supported on a tool feed table (1) of a lathe so that the pivot can be turned, the pivot (3) being provided at the portion thereof which is near the front end thereof with an external thread (3a) and at the front end portion thereof with a stopper (3b). A nut (5) is engaged unitarily with a tool rest (2) so that a surface (5a) of the nut is opposed to the stopper (3b). A coupling means (6) consisting of a movable coupling (6a) and a fixed coupling (6b) is provided between the tool rest (2) and tool feed table (1). The movement of the tool rest (2) is restricted by locking means (2a, 9). When a driving motor (11) is rotated forward, the pivot (3) is turned forward via gears (12, 10), and the nut (5) and tool rest (2) leaves the tool feed table (1) as the turning of the nut (5) and tool rest (2) is prevented by the locking means. When the nut (5) engages the stopper (3b), the tool rest (2) overcomes the restrictive force of the locking means (2a, 9) and index-turns. When the pivot (3) is turned in the opposite direction, the reverse actions are obtained.</p> |
