Patent ID: 8813446

Claim:
In combination: a concrete component; a threaded anchorage member; and a cast-in insert embedded in the concrete component during casting, of the concrete component, wherein the cast-in insert has a tubular cavity for receiving the threaded anchorage member, the tubular cavity has an opening facing outward of the concrete component for insertion of the threaded anchorage member, wherein the insert is externally tapered such that when the anchorage member is threadedly engaged within the tubular cavity, axial loading applied to the anchorage member to withdraw the anchorage member from the insert causes reactional force from the surrounding concrete to be applied to the insert in a direction radially inwardly of the insert, wherein the insert is formed of deformable plastic material such that said reactional force in turn causes the insert to exert force radially inwardly upon the anchorage member; and wherein an internal surface defining the tubular cavity is provided with grooves extending longitudinally of the insert, the grooves defining therebetween a series of angularly spaced surfaces which contract onto the anchorage member in response to the reactional force.