Patent ID: 8562047

Claim:
A method of lifting an open-frame steel joist, said open-frame steel joist comprising a double-angle flange with an open web, the double angle flange having a gap “g” between the upright legs of the angles that form the double-angle flange and a dimension “t i ,” which is the distance between the outer surfaces of the vertical legs of the angles that form the double-angle flange, the method comprising: providing a lifting hook, said lifting hook comprising a casing, a shaft and a resilient member, the casing having a lower bearing surface, the shaft comprising an elongate rod having a diameter selected to be less than the gap “g” between the upright legs of the double-angle flange, the elongate rod passing through the casing and having a hook member disposed outside of and adjacent to the lower bearing surface of the casing, the hook member comprising a generally U-shaped body having a transverse width “w” selected to be less than gap “g” of the double-angle flange and throat dimension “t 2 ” selected to be larger than the dimension “t 1 ,” of the double-angle flange, the resilient member urging the hook member toward the lower bearing surface of the casing, inserting the hook member between the upright legs of the angles that form the double-angle flange until the lower bearing surface of the casing engages the flange; pressing against the shaft with hand pressure to extend the hook member against the force of the resilient member until the hook member extends below the double-angle flange; rotating the shaft approximately 90°; and releasing the hand pressure to allow the resilient member to move the hook member upward to engage the double-angle flange.