Drill for hand-held drilling devices

Claim 1

A drill for use in a hand-held drilling device comprises an axially elongated shank arranged to be inserted into the hand-held device, said shank having an axially extending outside circumferential surface with a closed ended axially extending groove formed in the axially extending outside circumferential surface and said groove having ends extending transversely of the axially extending direction thereof, wherein the improvement comprises that said shank has a leading end, a trailing end, and a diameter D, the axially extending distance between the trailing end of said shank and the adjacent end of said axially extending groove is in the range of 0.3 to 1 times the diameter D of said shank, at least one web is located within said axially extending groove extending in the axially extending direction of said groove and also transversely thereof and divides said groove intermediate the ends thereof into axially extending groove sections, the surface of said web is located in the outside circumferential surface of said shank, each said groove section has a base spaced radially inwardly from the outside circumferential surface of said shank with said base extending parallel to the axis of said shank and each said groove section having opposite ends spaced apart in the axial direction with said groove section ends forming shoulders extending transversely of the axial direction.