| 摘要 |
<p>The turret for an automatic lathe or a numerically controlled machine tool has a base with a rotatable tool holder (11). The tool holder is held in a fixed position by spring which keeps the toothed wheels in engagement. When the central shaft (13) is rotated by a worm and wheel drive it is screwed out of bush (12) so that the tool holder is pushed upwards and the toothed wheels disengaged. When the direction of drive is reversed the spring loaded pawls (22) engage the teeth of the ratchet wheel. This causes the tool holder to rotate through 90 deg. as it is forced downwards by the spring so that the theeth of the wheels mesh with each other again.</p> |
