Expansion anchor assembly

Claim 1

Expansion anchor assembly arranged to be secured in a borehole formed in a receiving material, comprising an axially elongated expansion sleeve having a first end and a second end spaced apart in the axial direction, and an axially elongated anchor rod arranged to extend through said sleeve, said anchor rod having a first end and a second end, said expansion sleeve having a plurality of expansion sections extending axially from the first end toward the second end of said expansion sleeve, said expansion sections are spaced apart in the circumferential direction by axially extending slots, said anchor rod has an expansion cone on the first end thereof for displacing said expansion sections radially outwardly when said cone is drawn into the first end of said sleeve toward the second end thereof, each of said expansion sections has a circumferentially extending weakened section spaced axially from the first end of the expansion sleeve, said weakened sections are located between a first recess formed in a radially inner surface of said expansion sections and a second recess formed in a radially outer surface of said expansion sections, said weakened sections acting as a bending location for said expansion sections, wherein the improvement comprises that each of said first and second recesses has a base extending rectilinearly and tangentially relative to the axis of said expansion sleeve, said first and second recess bases are located in a common plane disposed normal to the axis of said expansion sleeve, and said weakened sections in combination form a hollow rectangular cross section transversely of the expansion sleeve axis.