US 4,017,115 A · Lift system for concrete slabs

Abstract

A lifting anchor for incorporation into a poured concrete slab. The anchor comprises a steel sleeve having an irregular exterior surface to effect a bond between the sleeve and the concrete of the slab and an interior surface defining a cylindrical opening formed with an annular abutment. During pouring, concrete is excluded from the interior of the sleeve opening by a plastic cap clipped onto the exterior of the bottom end of the sleeve and a plastic plug telescoped into the upper end of the sleeve. After formation of a slab with the anchor in place, the plug is removable to afford access to the interior of the sleeve. A hoisting coupling is engagable with the anchor through means of a cylindrical body sized for entry into the sleeve. The inner end of the body is provided with a pair of lugs which can be extended radially outward to engage the abutment of the sleeve and contracted radially inward to afford removal of the body from the sleeve. The lugs are selectively movable between the extended and retracted positions through means of an actuating rod extending axially of the body. The outer end of the actuator rod has a device for applying tension thereto so as to permit disengagement of the lugs from the abutment from a remote location. A hoisting bail is secured to the exterior of the coupling to enable the coupling to be engaged by the lifting hook of a crane.

Claims18

Dependent claims

A remotely releasable hoisting coupling for selective engagement with a concrete slab having a surface, a cylindric passage formed in the slab in generally perpendicular relationship to the surface and opening therethrough, and an annular abutment within the passage below the surface, said coupling comprising:

a cylindric body sized for entry into said passage;
at least one lug engagable with said abutment and supported in said body for movement relative thereto between a position protruding laterally from said body at which the lug engages the abutment and a position retracted into said body at which the lug is disengaged from the abutment, said body defining a central bore;
an actuator rod axially movable in said bore and having an inner end operatively connected to said lug and an outer end accessible from the surface of the slab;
means operatively connecting said lug to said actuator rod so that in response to axial movement of the actuator rod in one direction relative said body said lug is moved to the retracted position and, in response to axial movement of the actuator rod in an opposite direction relative to said body, said lug is moved to the protruding position;
means within said body for resiliently biasing said actuator rod in said opposite direction so as to correspondingly bias said lug to the protruding position;
means secured to the externally accessible end of said actuator rod for selectively moving the rod axially in said one direction to move the lug to the retracted position;
and, means secured to said body exterior of the slab for affording attachment of a hoisting line thereto.

4 more elements

An anchor assembly for forming in a concrete slab a socket engagable with a hoisting coupling, said assembly comprising:

a sleeve defining a cylindric passage therethrough, the passage having a first opening at one end thereof and a second opening at the opposite end thereof, said first opening being counterbored to define an annular abutment within said passage and substantially perpendicular to the axis thereof;
an impervious cap secured to said sleeve and spanning said first opening to exclude concrete from said passage;
an impervious tubular member secured to said sleeve in coaxial alignment with said passage at said second opening, said tubular member defining a cylindric opening having a larger diameter than said passage, said tubular member having integral therewith a frusto-conical flange converging from an outer diameter equal to the cylindric opening in said tubular member to an inner diameter equal to said first opening;
and an impervious plug sized to fit within said tubular member to exclude the entry of concrete into the member, said plug having an axial extent sufficient to extend to said slab surface.

1 more element

Dependencies are inferred from the claim text.

Lift system for concrete slabs

Life of this patent

Lift system for concrete slabs

Life of this patent

Abstract

Claims18