Core drilling machine, particularly hand-held core drill machine, has transmission with two gears having two transformation ratios, where drill bit is driven in former gear and pilot drill is driven in latter gear

摘要

The core drilling machine (10) has a motor (18) which is coupled to the drive by a transmission (19) with a drilling spindle. A tool holder (20) is provided at the drilling spindle for receiving a drill bit (22). A centering receptacle is provided for receiving a pilot drill (23) coaxial to drill bit. The transmission has two gears with two transformation ratios. The drill bit is driven in the former gear and the pilot drill is driven in the latter gear. An independent claim is included for a drill bit with a transmission unit.