| 摘要 |
A positive feed drill having a spindle drive gear train and a spindle feed gear train coupled to the drive gear train is provided with means for uncoupling the feed coupling gear from the drive coupling gear, and locking the feed coupling gear when the spindle has been fed a predetermined extent, thereby placing the drill in retract mode, and for unlocking the feed coupling gear, once the spindle is retracted, without recoupling it to the drive gear train, thereby placing the feed gear train in an idle mode until the aforesaid uncoupling means is manually reset. The drill is further provided with a rapid advance coupling gear keyed to drive a shaft which turns the drive coupling gear and with a rapid advance idle gear meshed with the rapid advance coupling gear. The gear ratio of the rapid advance coupling gear to the rapid advance idle gear is selected to be greater than the gear ratio of the feed coupling gear to the normal idle feed gear. A rapid advance control button, when depressed, will place the drill in the idle mode if not already in the idle mode and will force the rapid advance idle gear toward the feed coupling idle gear causing a clutch between those two idle gears to engage.
|
