| 摘要 |
A control system for an air driven drill is described, wherein the control system is of the kind that provides a feed stroke to a drill bit. The system comprises an interrupt line so that compressed air fed to a feed chamber is also fed to a clamp chamber whereby the unbalanced force on the feed piston becomes balanced so as to stop the feed stroke. An adjustable frequency generator is provided to impose a pulsating pressure variation in an air pressure supply. During a feed stroke under which compressed air is fed to the feed chamber, air fed to the clamp chamber via the interrupt line is caused by the adjustable frequency generator to have a pulsating pressure, so that the feed stroke is caused to be stopped for a first period, then resumed for a second period, to provide a periodically interrupted feed stroke. |
