Abstract: Piloted electromagnetic brake for controlling the tension of the weft threads in weaving machines, in particular of a weft thread which has a high number of knots, of the type including a pair of opposite elastic thin plates between which the weft thread runs, an operated thin plate being adjusted in position by an electromagnetically controlled operating piston, and a resisting thin plate being resistant against an elastic contrast unit, in order to control the intensity of the contrast force between the pair of thin plates. The resisting thin plate and the operated thin plate have fulcrum points in correspondence of a central portion thereof, so as to be able to freely oscillate in a plane containing the weft thread, during the passage of a knot between them, and the fulcrum points are offset by a set length along the weft thread running direction.

Abstract: A reflection optical sensor (F1-F4) for the detection of a weft thread in a weaving weft feeder (P) comprises a light emitter (1) and a light receiver (2) assembled on a relative supply printed circuit board (3) and housed in an arm (A) of the weft feeder which projects towards the front part of the weft feeder (P) and extends alongside the weft feeder drum (D) whereon the weft thread coils are wound, so as to form a path of direct light radiation, from said light emitter (1) towards a respective reflective surface (R) placed on said drum (D), and of reflected light radiation, from said reflective surface (R) to said light receiver (2), for detecting the presence/absence of a weft thread running through said path. Said light emitter (1) and light receiver (2) are assembled with mutually parallel optical axes on said supply printed circuit board (3).

Abstract: A weft feeder device for threads, in particular for weaving looms, of the type comprising a main body (1) within which there is housed an electric motor for the driving of a rotary shaft (2), the rotary shaft (2) driving into rotation, with its middle portion, a rotor (3), and a drum (T) rotatably mounted on the end portion of said rotary shaft (2) and kept fixed by magnetic means (6, 7), and wherein there are furthermore provided pairs of optical emitting/receiving sensors (E, R) are respectively arranged on the drum (T) and on an extension of the main body (I) of the weft feeder device which extends laterally to the lateral surface of the drum (T), said pairs of sensors (E, R) being apt to detect the presence/absence of a thread passing therebetween.

Abstract: Group of optic sensors (S) in a weft feeder, in particular for weaving looms, comprising one or more pairs of emitting sensors (E) and receiving sensors (R) arranged on a portion of the weft feeder (C) which extends laterally to the drum (T) of the weft feeder whereon the coils of the weft thread are wound, so as to form optic radiation going-paths from each of said emitting sensors (E) to a reflecting surface (9) provided on said drum (T) and optic radiation back-paths, from said reflecting surface (9) to corresponding receiving sensors (R), for detecting the presence/absence of a thread which crosses said paths. The optic sensors (E, R) are of the SMT type and are wired on a printed-circuit board (8) with an optic axis parallel to the plane of said board (8). A first group of total-reflection mirrors (V), one for each pair of emitting/receiving sensors (E, R), is inclined so as to deviate the optic radiation from the plane of the board (8) to a plane perpendicular to or inclined with respect to the same.

Abstract: A weft feeder device for threads, in particular for weaving looms, of the type comprising a main body (1) within which there is housed an electric motor for the driving of a rotary shaft (2), the rotary shaft (2) driving into rotation, with its middle portion, a rotor (3), and a drum (T) rotatably mounted on the end portion of said rotary shaft (2) and kept fixed by magnetic means (6, 7), and wherein there are furthermore provided pairs of optical emitting/receiving sensors (E, R) are respectively arranged on the drum (T) and on an extension of the main body (I) of the weft feeder device which extends laterally to the lateral surface of the drum (T), said pairs of sensors (E, R) being apt to detect the presence/absence of a thread passing therebetween.