The system is very simple, a lever rotates on the primary shaft and makes contact with a cam one time per revolution. When this cam is pushed, it pulls on a rod which operates the main pushed system (green beam). This device allows the system to push the shuttle during the overall crossing through the threads. Even if the slider is a bit smaller, the reed is a bit wrong placed or the threads are a bit not enough tight, the shuttle is forced to pass through. Thanks to that, the system is always in contact with the shuttle, resulting in a significantly increasing of reliability.