The drill device has a body with a front end and a rear end and which is connectable to the shaft of a drilling apparatus. A plurality of angularly spaced apart slots are formed in the exterior of the device which extend between the front and rear ends. Each slot has a lip extending from each of its...http://www.google.fr/patents/US6702046?utm_source=gb-gplus-shareBrevet US6702046 - Drill device for a drilling apparatus
