Abstract: A rotatable thread arrester, associated with a thread feeder, includes an arrester finger for the thread that is movable with respect to the reel of the feeder under the control of a movement device and engages the thread so as to stop its unwinding from the reel and viceversa in order to damp the peak of the mechanical tension generated on the thread by the contact with the arrester finger. The arrester finger is oscillatably suspended about an axis "x" that is parallel to the axis "y" of the reel and is controlled by the action of a motor which rotates the arrester in the thread unwinding direction, so that the arrester finger, in the arresting position, follows the thread unwinding from the reel.

Abstract: Device for positive modulated braking of weft feeder thread, including a braking body, typically a frustum-shaped braking body, that is supported frontally and coaxially to the drum of the feeder in order to directly or indirectly engage the thread that unwinds from the drum. The braking body is subjected to the action of an electromechanical actuator, supplied by an excitation current that is modulated so as to match the variation in the mechanical tension of the thread during the weaving process; the braking body is rigidly coupled to a support that is movable in the axial direction of the drum of the feeder and is supported and guided by a fixed support.

Abstract: A device for separating reserve turns of thread on a weft feeder drum comprising a swift that is formed by a set of axial rods that partially and variably protrude from respective slots formed on the drum of the feeder by virtue of the compound motion applied to the swift by a bush that is associated with the drive shaft. The bush is supported by a recessed coaxial portion of the drive shaft, and a diametrical pin is provided which is arranged so as to cross said shaft and said bush, and to bring about a pivotal engagement between said shaft and said bush. The bush has a cylindrical and eccentric outer surface and an internal surface that is profiled so as to form two portions of truncated-cone surfaces. The bush can thus oscillate about the pin and be arranged at an angle with respect to the drive shaft. An actuation element is provided to vary the inclination of the bush when the bush is rotated with respect to the element, which is kept fixed by a pushbutton stop device.

Abstract: A modulated thread beating device for weft feeders has a first lamina and a second lamina that are arranged opposite one another and are supported by pairs of fixed and respectively movable bars that engage the ends of the respective laminae, flexing them in an arched shape; the laminae are arranged opposite each other at their convex face. The movable bars are supported by a corresponding movable element which is suspended elastically and is provided with an energization coil that is subjected to the field of a permanent magnet. The coil of the movable element is supplied with an energization current that is modulated in proportion to the advancement speed or mechanical tension of the thread.

Abstract: The breaking device has a single truncated-cone braking body, supported by an elastic member coaxially and frontally with respect to a drum of a feed unit and is actuated by the elastic member so that it engages, with an elastic contact, against the drum along a circumference thereof which is smaller than the maximum circumference of the drum. The thread slides between the drum and the braking body and extends from a point of contact with the drum and braking body along a path which is inclined with respect to the axis of the drum, so that the tension produced by the braking body has at least one axial component which is discharged onto the braking body and is balanced by the elastic member. Increase in the tension on the thread produces, or tends to produce, by virtue of the corresponding increase in axial component, separation of the braking body from the drum with a corresponding self-adjusting braking action.

Abstract: A weft feeder for weaving looms including a fixed drum, a rotating arm winding, a plurality of thread turns on said drum, an asynchronous motor for said rotating arm, braking means for breaking thread unwinding from said fixed drum, a guiding ring for guiding unwound thread and a piezoelectric transducer rigidly associated to the side of the solid of revolution generated by the unwinding thread and adapted to emit an electric pulse upon every passage of the thread at the generatrix of the solid of revolution which is arranged in the meridian plane which contains or intersects the axis of a feeler associated with the transducer.

Abstract: A weft feeding device, for weaving looms, of the type comprising a drum for winding the thread and an array of metallic laminas for braking the thread which unwinds from the drum. The metallic laminas are arranged on the surface of a rotational paraboloid. The paraboloid is fitted on the drum and is tangent thereto, to elastically engage a thread, at its own minimum-radius circumference. The paraboloid has one end rigidly coupled to a fixed supporting ring which encircles the drum, the other free of the paraboloid end being subject to the action of a movable ring which, when moved axially with respect to the paraboloid, varies the paraboloid's curvature in order to correspondingly vary the contact pressure of the laminas on the thread.