Reinforcing bar, bolt or the like

Claim 1

In combination, a sleeve with a female helical thread and at least one rod having a core of circular cross-section provided with two sets of transverse ribs extending in planes perpendicular to the core axis over an arc of substantially 180* on diametricaly opposite surface portions thereof, the ribs of each set having a uniform spacing equal to the pitch of said thread, the ribs of said sets being relatively staggered by half said pitch, said sleeve having an inner diameter less than the width of said rod in a radial plane bisecting said ribs but greater than the diameter of said rod in a median plane perpendicular thereto, said ribs having roots of outwardly concave axial section whose width progressively decreases from said radial plane to said median plane, said rod entering said sleeve with said thread matingly engaging certain of said ribs, said ribs having flat crests of uniform axial width over their entire length, said ribs being faired into the surface of said core at said median plane.