US Patent 7140399 Shaft drive system for power loom shafts

A novel shaft gear for harmonious engagement and disengagement of individual heddle shafts and for deriving their motion from the rotary motion of a single input shaft has a coupling system with two input elements. While one of the input elements serves to drive the output element of the coupling system permanently, the other input element serves solely to synchronize the output element briefly with the first input element. The switchover takes place in the brief synchronous phases, in selected angular regions that correspond to the top or bottom reversal point of the heddle shaft. For the switchover, such novel shaft drive mechanisms do not require any stoppage of motion for the input shaft or the shaft drive mechanism.