Abstract: A piezoelectric transducer for yarn feelers for fitting to spinning and weaving machines and devices, constituted by a single ceramic member incorporating the yarn guide and cemented directly to a ceramic piezoelectric element, the size and shape of said member being chosen such that its resonance frequencies are very different from those of the textile machines and devices to which the yarn feeler is to be fitted.

Abstract: An optical sensor of the barrier type for air jet weaving looms comprises two equally orientated, parallel photoelements and two very thin total-transmission optical prisms aligned with the photoelements and insertable between and the reed blades in order to deviate the light rays between the photoelements so that they cross the weft yarn passage channel in the reed.

Abstract: A weft yarn presenting device for shuttleless looms, especially air looms, feeding weft yarns of different colors, comprises a plurality of nozzles joined in a bundle and carried by a body mounted on two supports arranged at 90.degree. one from the other, and two actuators adapted to be operated simultaneously and imparting to said supports rectilinear movements in both senses, along two directions perpendicular to each other and to said body.

Abstract: An electric device for the control of yarn feeding devices for weaving machines, of the type providing for the presence of a yarn supply wound onto a drum and comprising an electric three-phase driving motor, wherein, in order to change the speed of the motor, this latter is supplied with AC voltage, phase controlled by triacs. For this purpose, three signals are used representing a selected speed for the motor, the true speed of the motor itself and, respectively, the presence of the yarn supply on the drum, these signals being compared and processed into an electronic circuit, in order to produce signals forthe control of the triacs. The three signals are compared in a circuit generating a signal which must in turn be compared with three periodic ramp signals having the same phase and a period half those of the three supply voltages of the motor, in order to generate square wave signals for energizing the corresponding triacs.

Abstract: A device for feeding yarn with a constant adjustable tension, for use in weaving looms and in other weaving machines, comprises a brake acting on an end cap of the winding drum--held stationary--of the device. The brake is a plurality of elastically yielding metal elements, positioned radially in a support designed to envelope the cap and mounted with possibility of self-centering in respect of the cap, these elements engaging the outcoming yarn about a circumferential area of the cap having a slightly smaller diameter than that of the winding drum of the feeding device.

Abstract: In a yarn feeding device with constant adjustable tension, for use in weaving and knitting machines, of the type comprising a fixed hollow body around which the yarn to be fed is wound by an external rotary element, to form thereon a yarn reserve from which the yarn is drawn to be sent to said weaving or knitting machine, passing through the inside of said fixed hollow body, a brake is provided which acts by pressing the yarn onto the edge of the said fixed body. The brake comprises a plurality of substantially radial elements of thin sheet-metal, held at the ends between an outer ring and a central hub of plastic material, which are moreover connected to each other by radial elastic laminae, said substantially radial elements being designed to be pressed onto the edge of the fixed body of said feeding device, to brake the yarn thereon thanks to the action of an adjustable setscrew which freely engages the center of said central hub, said outer ring being arranged beyond the edge of said fixed body.

Abstract: Electronic device for controlling weft yarn insertion in continuous weft feed looms, without shuttles, adapted to stop the loom and emit a corresponding signal, not only each time there is a breakage or absence of a weft yarn, but also whenever the undesired insertion of double wefts occurs. This device comprises a plurality of transducers, each activated by a weft yarn, a logic network and means for stopping the loom, said logic network comprising means for storing a predetermined law of insertion of the individual weft yarns corresponding to a certain weaving operation on the loom, and for comparing with said law the actual weft insertions detected by the transducers.