Self-seating expansion anchor

Abstract

An expansion anchor received within a predrilled bore for mounting a platelike panel to a portion of stratum in which the bore is drilled and including a bolt having a head on a lower end thereof, an upper portion, distal the head, defining a set of right hand threads thereon and a lower portion, intermediate the upper portion and the head, defining a set of left hand threads thereon. A destructible thrust nut having at least one groove therein is threadably connected to the lower portion and moves upwardly thereon when the rod is rotated in a clockwise direction. A cutting member, having an annular base supported by the thrust nut for sliding movement along the bolt and a plurality of cutting fingers connected to the base in divergent relation to the bolt, is urged upwardly by the thrust nut when the rod is rotated in the predetermined direction. The cutting fingers have at least one blade extending transversely thereon for cutting a groove in the stratum to expand the diameter of the bore a predetermined depth therein. An expansion nut is threadably connected to the upper portion and moves downwardly thereon to expand the cutting fingers and thereby direct the upwardly mobile cutting blades into the stratum. The downward motion of the expansion nut seats the fingers within the grooves cut thereby and secures the bolt within the bore. A rupturable resin container is provided to dispense catalyst activated resin within the bore to further secure the expansion anchor therein.