Abstract: The system for controlling the unwinding of the warp in a loom includes at least two warp beams and two electric motors for rotating the respective warp beams. Two sensor devices detect the tension of the warp threads which unwind from the two beams and are connected to two electronic regulation devices each associated with a respective motor for regulating the speeds of the motors so as to keep the tension of the warp substantially uniform. A switch is interposed between the sensors and the regulation devices for switching the connections between the sensors and the regulation devices at a predetermined frequency higher than the frequency at which the weft is beaten up in the loom.

Abstract: In order to prevent the formation of weft streaks in cloth when a loom is restarted after a stoppage, the warp tension is reduced by a predetermined amount as soon as the stoppage occurs and the original warp tension is restored before restarting. The reduction in the warp tension prevents the tensile failure, that is, the plastic extension of the warp yarn, and ensures the exact repositioning of the beating-up line of the weft upon restarting.

Abstract: The loom includes a reed constituted by a plurality of blades which are in alignment and parallel to each other. These blades have respective substantially circular apertures which have the same diameter and are aligned with each other to form a straight passage for guiding the pneumatic insertion of the weft. The portion of each blade between the aperture and the side of the blade facing the fabric (T), in use, has a substantially horizontal slit which extends from the aperture to the side of the blade. Between each pair of adjacent blades are interposed first and second spacer elements which are arranged respectively above and below the aperture and the slit of the blade. The loom includes drive means which, when activated, cause translational movement of the reed perpendicular to the longitudinal axis of the passage formed by the apertures in the blades of the reed.