| 摘要 |
<p>A quick return mechanism for a drilling machine comprises an input shaft (9), an output shaft (10), an over-drive gear train (19) and a speed-reduction gear train (23), each disposed between the input and output shafts (9, 10), a first clutch (18) for connecting the output shaft (10) to the input shaft (9) through the over-drive gear train (19) when a motor (13) for driving the input shaft (9) rotates in the quick-return direction and disconnecting the output shaft (10) from the input shaft (9) when the motor (13) rotates in the feed direction, a second clutch (22) selectively set at a first position and a second position, for connecting the output shaft (10) to the input shaft (9) through the speed-reduction gear train (23) at the first position when the motor (13) is rotated in the feed direction, and disconnecting the output shaft (10) from the input shaft (9) through the speed-reduction gear train (23) at said second position, when the motor (13) rotates in the quick-return direction, and a rotation=linear-movement converting unit (32) for setting the second clutch (22) at the first position when the motor (13) rotates in the feed direction, and at the second position when the motor (13) rotates in the quick-return direction. <IMAGE></p> |
