Threaded Rebar Coupler Using Pitch Mismatch to Prevent Loosening

The patent applies parameter changes by intentionally using mismatched screw pitches (P6, P7 different from P4) and different phases between the reinforcing bar thread and the outer peripheral screws. This deliberate parameter mismatch induces galling between the threads, which prevents loosening and improves fastening reliability without requiring high manufacturing precision.

The patent employs self-service by utilizing the galling effect that occurs naturally between the mismatched threads during the normal fastening process. The galling itself serves as the locking mechanism, eliminating the need for additional fastening methods like grout or screw locks, thereby maintaining simple coupler structure while achieving reliable fastening.

The patent converts the potential harm of pitch mismatch into a beneficial galling effect. By intentionally designing mismatched screw pitches and phases, the patent transforms what would normally be a manufacturing defect into a useful locking mechanism that prevents loosening, thereby improving anti-loosening performance while maintaining reasonable manufacturing precision requirements.