Expansion dowel assembly with an expansion cone displaceable into an expansion sleeve

Claim 1

An expansion dowel assembly for insertion into a borehole in a receiving material and having a leading end and a trailing end relative to the insertion direction of the dowel assembly into the borehole, the dowel assembly including an axially extending expansion sleeve with a leading end and a trailing end and a bore extending axially therethrough, said sleeve having a cylindrically shaped outer surface, said expansion sleeve having an axially extending expansion region adjacent the leading end thereof with the bore in said expansion region widening toward the leading end, said expansion sleeve having circumferentially spaced axially extending slots extending from the leading end toward the trailing end thereof and extending at least for the axial extent of the expansion region, and an axially extending anchor bolt having a leading end and a trailing end and extending through said bore in said expansion sleeve with the leading end of said anchor bolt having an expansion cone widening in the insertion direction and arranged to be drawn into the leading end of said expansion sleeve toward the trailing end thereof for expanding said expansion sleeve, wherein the improvement comprises that: (a) said expansion cone has a cone angle and said expansion region has a cone angle and the cone angle of said expansion cone is larger than the cone angle of said expansion region; (b) said expansion sleeve in said expansion region has a variable wall thickness in the circumferential direction with the wall thickness diminishing in the direction toward said slots, the radius of said outer surface of said expansion sleeve being centered on the axis thereof, said expansion sleeve having an inner surface eccentrically arranged relative to the axis thereof; and (c) the outer surface of said expansion region has a circumferentially extending annular bear projecting outwardly from the outer surface of said expansion sleeve.