Anchor insert and pickup unit assembly for a concrete slab

Claim 1

In combination, an anchor insert adapted for embedment in a concrete slab and a cooperating pickup unit therefor, said anchor insert comprising a tubular concrete-excluding shield across and through which there extends a single embedment rod defining an elongated downwardly facing thrust shoulder, said shield presenting an open upper rim, said pickup unit comprising a tubular member having a flat underneath surface adapted for positioning on the upper surface of the slab and also having formed therethrough a vertical bore designed for register with said upper rim of the shield when the member is in position on the slab, a torque stem projecting completely and loosely through said bore and having on its lower end a pair of laterally spaced apart, upwardly opening, oppositely facing hooks which face generally toward each other and are formed with bottom rodengaging lift surfaces which are in diametric alignment with respect to the axis of the torque stem, said hooks being designed for interlocking engagement with said thrust shoulder when the stem is projected through said open rim to an extent sufficient to project said hooks below the level of said rod on opposite sides of the latter and then for turning movement through an angle in order to bring the hooks into simultaneous interlocking register with the rod, the lower end of the torque stem being bifurcated in order to provide two identical spaced apart depending hook portions including vertical hook shanks with reentrant bends terminating in upwardly projecting hook fingers, thus establishing said hooks, said reentrant bends establishing said lift surfaces, the distance between said hook portions and the curvature of said reentrant bends being such that when said hooks are below the level of said rod on opposite sides thereof, turning of the torque stem about its vertical axis is limited to approximately 60* whereby when the hooks are interlocked with the rod, the latter projects through the hook portions obliquely with respect to the general plane of the latter, the lower region of the torque stem immediately above the bifurcated end thereof being formed with a vertically disposed elongated axial socket which faces downwardly, and the pickup unit further comprising a biasing plunger which is slidable disposed in said socket and projects into the bifurcation of the stem for engagement with the upper portion of the exposed embedment rod section, spring means yieldingly biasing the plunger to its projected position, interengaging means on the plunger and torque stem for preventing withdrawal of the plunger from said socket, and a bail pivoted to said member and forming means whereby the pickup unit may be attached to an overhead hoisting mechanism for slab-lifting purposes.