The "couplerbox" assembly system is designed to implement mechanical links between reinforcements in concrete constructions. The Couplerbox joining device combines safety and technical performance thanks to its special rolled cylindrical threads. The sleeved assembly resists static and dynamic solicitations particularly well.
The cylindrical thread offers the benefit, versus the conical thread, of maintaining its full strength even if loosened by two or three turns. For example this could occur if soil has entered the sleeve before fitting the second stage bar.<br/>Unlike the cut thread, the rolled thread does not dig in the steel, hence does not create an incipient crack (resistance to fatigue). By warping the fibres without cutting them, the material is pushed back, increasing the thread's cross-section, strength and hardness.
4. CAF type coupler, straight bar in B500B fitted with a sleeve at one of the ends and from one thread to the other.