Iro Ab

Roj S.r.l.

Renato Comotto

Matteo Fazzari

Joachim Fritzson

Kurt Arne Gunnar Jacobsson

Paolo Ricci

Enzo Dandolo

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.

Piloted electromagnetic brake for controlling the tension of the weft yarn in weaving machines

A reflection optical sensor (F-F) for the detection of a weft thread in a weaving weft feeder (P) comprises a light emitter () and a light receiver () assembled on a relative supply printed circuit board () 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 () 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 (), for detecting the presence/absence of a weft thread running through said path. Said light emitter () and light receiver () are assembled with mutually parallel optical axes on said supply printed circuit board (). The optical sensor further includes a screening means () of the reflected radiation coming from said reflective surface (R) and directed towards said light receiver ().

Weft thread reflection optical sensor in a weaving weft feeder

A yarn braking device includes a braking body with the shape of a frustocone coat. The braking body is put over a rounded withdrawal end of a storage body and is pressed from the small diameter end by a resilient axial force against the withdrawal end. The axial force defines the braking effect between the braking body and the withdrawal end. Between a stationary holder and the braking body an axial force generator and a centering device acting in radial direction are provided. The axial force generator is formed by at least one pair of permanent magnets. The permanent magnets are axially aligned by the centering devices with an intermediate gap. The centering device neither is an axial sliding guiding system structurally and functionally separated from the pair of permanent magnets, or is formed free of contact directly by the pair of permanent magnets, respectively.

Yarn braking device

The invention relates to a thread tensioner comprising tensioning elements that define a thread tensioning zone. In said tensioner, the first tensioning element rests on a stop and the second tensioning element can be pressed against the first tensioning element by means of an adjustable magnet contact force produced by a magnet armature and a repelling magnet actuator. The stop is located on the opposite side of the thread tensioning zone from the first tensioning element. The first tensioning element is stressed by a spring force in the direction of the second tensioning element against the stop. Said spring force is greater in the thread tensioning zone than the respectively adjusted maximum magnetic contact force. The mass of the first tensioning element is smaller than the mass of the magnet armature.

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Biella, Italy

Renato Comotto