The warp yarn drawn from the bobbin on the bobbin frame first passes through the gap between the clamp and the column through the break detector, forward through the yarn guide porcelain plate, then through the yarn guide rod, through the expansion reed, around the length measuring roll and then wound to the warp shaft. The warp shaft can be dragged directly from the variable speed motor. When the winding diameter increases, the speed change signal is sent out by the tachometer generator connected with the measuring roll, and the speed of the motor is automatically reduced by the electrical control device to keep the winding speed of the warp shaft constant.