Patent ID: 8123429

Claim:
A reinforcing bar for concrete reinforcing comprising: a shaft extending along a portion of the length of the bar and a termination extending along an end portion of the bar, the termination being enlarged as compared to the shaft, wherein the termination incorporates an engagement face incorporating locking formations thereon arranged to interfit with a complementary shaped termination to form an interlock arranged to accommodate axial loading, wherein the locking formations comprise a plurality of spaced apart upstands extending transversely across the engagement face and a plurality of recesses disposed between adjacent ones of the upstands, each upstand includes opposite side walls interconnected by a bridging portion, and the opposing side walls of adjacent ones of the upstands defining respective ones of the recesses, wherein the interlock extends along an axis and the side walls include: bearing surfaces arranged to engage the complementary shaped termination in the interlock, the bearing surfaces extending at an angle of within 10° C. of the perpendicular to the direction of the interlock axis so that the reaction force at the interlock under axial loading does not induce separation of the terminations, first transition regions being formed above respective bearing surfaces and forming the intersection between the bearing surfaces and the bridging portions, and second transition regions extending from the respective bearing surfaces to base portions of the recesses, the first and second transition regions incorporating radii with the radius of the first transition regions being smaller than the radius of the second transition regions.