Rotary drilling tool for widening holes - has cutter carrier end attached to support ring on axially movable shaft

摘要

The drill shaft is clamped in a rotating, axially driven tool shaft. Radially displaceable cutters seated on resilient carriers led in drill shaft holes in the form of axial grooves, make up an appliance for drilling widening bore-holes. The end of the cutter carrier away from the cutter is fastened to a support ring on the tool shaft. This shaft is axially displaceable against the ring, against spring force, when the ring lies against the masonry. Cutters pref. have a cutting edge aligned parallel to the drill shaft axis. Cylindrical widening of a hole can be reliably effected in both soft and very hard material.