Collar for a concrete lifting anchor

Abstract

A collar for a concrete component lifting anchor including an attachment portion for attaching the collar to the lifting anchor, and an abutment portion adapted to provide a clutch abutment surface for limiting rotation of a clutch relative to the lifting anchor.

1 . A collar for an anchor for use in lifting a concrete component, said anchor comprising a head portion engageable with a clutch of a lifting system, and a body portion for embedment within the concrete component, the collar including an attachment portion for attaching the collar to the head portion of the anchor, and an abutment portion adapted to provide a clutch abutment surface for limiting rotation of the clutch relative to the anchor. 
     
     
         2 . A collar as claimed in  claim 1 , wherein when the collar is fitted to the anchor the abutment portion forms the clutch abutment surface as a shoulder adjacent the anchor. 
     
     
         3 . A collar as claimed in  claim 2 , wherein the clutch abutment surface is formed as a shoulder standing proud of the head portion for limiting rotation of the clutch about an eye of the head portion. 
     
     
         4 . A collar as claimed in  claim 3 , wherein the abutment portion provides a pair of opposed shoulders on the head portion for limiting rotation of the clutch about the eye in both directions of rotation. 
     
     
         5 . A collar as claimed in  claim 4 , including a gap between the shoulders which coincides with the eye of the head portion to allow passage of the clutch through the eye. 
     
     
         6 . A collar as claimed in  claim 5 , wherein the abutment portion is formed by an edge of the collar. 
     
     
         7 . A collar as claimed in  claim 1 , wherein the collar fits around the head portion, and is held to the head portion by way of a press fit. 
     
     
         8 . A collar as claimed in  claim 1 , wherein the collar is generally C-shaped. 
     
     
         9 . A collar as claimed in  claim 1 , including at least one shear bar attached to the collar. 
     
     
         10 . A collar as claimed in  claim 9 , wherein the shear bar engages in a groove of the collar. 
     
     
         11 . A collar as claimed in  claim 9 , wherein the shear bar is welded to the collar. 
     
     
         12 . A collar as claimed in  claim 9 , wherein the shear bar is formed in a generally wave-like shape, with oscillations in a direction generally perpendicular to a central axis of the anchor when the collar is fitted to the anchor. 
     
     
         13 . A collar as claimed in  claim 12 , including a second shear bar, wherein a major axis of the second shear bar is generally parallel to a major axis of the first shear bar and is substantially a mirror image of the first shear bar when viewed from an end of the anchor. 
     
     
         14 . An anchor for use in lifting a concrete component, said anchor comprising a single length of wire bent to form a head portion engagable with a clutch of a lifting system, and a body portion for embedment within the concrete component, wherein the anchor has a collar attached to the head portion to provide clutch abutment surfaces for limiting rotation of the clutch relative to the anchor, the collar being a collar as claimed in  claim 1 . 
     
     
         15 . An anchor system for use in lifting a concrete component, the assembly comprising
 an anchor formed from a one-piece elongate element shaped to form a head portion engageable by a clutch of a lifting system and a body portion for embedment within the concrete component; and   a collar carried by the head portion of the anchor to define at least one clutch abutment surface for limiting rotation of the clutch relative to the anchor.