A device for coupling a driver system to a downhole string of sucker rods in a petroleum well employs a polish rod construction in which the polish rod is strengthened by an attached sleeve providing a transverse should in a predetermined plane. The sleeve is shrink fit in place and mechanically adhered to withstand the stresses and shocks encountered in long-term cyclic operation. The device provides specific benefits for an improved sucker rod connection which prestresses the sucker rod pin ends and the coupling in a fashion to resist the development of microcracks and fatigue failures.