Abstract: A weft feeder for gripper or projectile looms allows an operator promptly to restore the continuity of a weft yarn from a yarn feed spool to members for weft insertion into a loom shed, in case of weft yarn breakage or interruption. Downstream of a first yarn guide outlet, there are mounted a double-leaf brake, a separating element, and a second downstream yarn guide eyelet. The separating element is controlled by an actuator so as to separate two brake leaves of the double-leaf brake and to form a duct to guide the weft yarn from the first eyelet to the second eyelet.
Abstract: A measuring weft feeder for fluid jet looms which measures the weft yarn lengths being inserted into the loom shed is disclosed. The weft feeder comprises an electric motor for rotating a winding arm, a drum held stationary around which the arm winds up the yarn into even turns, forming a weft yarn reserve whose length is controlled by means of suitable sensors, and a yarn stopping device. The yarn stopping device includes a rod for engaging and stopping the yarn at the outlet of the feeder. The rod is movable between a withdrawn rest position and a projecting yarn stopping position in which its end moves into a cavity formed for such purpose on the drum periphery, close to the free end thereof. The drum cavity has mounted therein a plurality of bristles positioned transversely to the rod of the yarn stopping device, so that the rod may engage the bristles, crossing them at least partially, when assuming its projected position to stop the weft yarn.
Abstract: In a measuring weft feeder for fluid jet looms, of the type having a winding unit with adjustable cross section and comprising a cage wall formed of two sets of alternating columns mounted on reciprocally slanting flanges so as to move forward the yarn reserve into separate turns. The sets of columns (preferably divided into evenly spaced groups or sectors) are mounted on the respective flanges by way of structure adopted to adjust their radial position, this structure acting simultaneously and to an equal extent on both sets of columns and being operated by a single control member.
Abstract: An instrument for measuring the tension of yarns--particularly weft yarns which wind or unwind forming a "balloon"--avoiding further deviations thereof, which makes use of a variable impedance, for example a differential capacitor or a variable inductor, comprising a movable component and at least one fixed component as parts of an electric measuring circuit. All the components of the instrument have a centered symmetry and a passage through their center for the yarn whose tension has to be measured, with a yarn guiding and deviating eyelet positioned in correspondence of the closing vertex of the "balloon" and fixed to the movable component of the variable impedance. The variable voltage detected on one of the components of the impedance, as a function of the tension of the yarn sliding through the eyelet, is measured by a measuring device connected to the movable component.
Abstract: A weft feeder for gripper or projectile looms comprising a body housing a motor, a drum idly mounted on the motor shaft and held stationary around which a winding arm rotated by the motor winds up a weft yarn reserve, a bracket positioned alongside the drum and carrying sensors to detect and control the yarn reserve as well as a brake to stop the yarn against the end surface of the drum, and three compressed air devices acting on the yarn to automatically restore the continuity of the weft yarn from the feed spool to the loom is disclosed. The first device is positioned at the inlet of the weft feeder to withdraw therefrom broken yarn and introduce therein new yarn fed by the spool. The second device is positioned adjacent to the weft feeder drum to receive the new yarn fed by the first device and by the winding arm to send it to a fixed point. The third device consists of at least a suction nozzle mounted, downstream of the brake, at the end of the weft feeder bracket positioned alongside the drum.
Abstract: In a measuring weft feeder for fluid jet looms, the continuity of the weft yarn from the feed spool or reel to the main nozzle of the loom is automatically restored by two compressed air devices acting on the weft yarn, the first of which--positioned at the inlet of the weft feeder, to withdraw therefrom the broken yarn and introduce therein new yarn fed by the spool or reel--comprises a first duct connected to the inlet of the weft feeder, along which duct there are positioned a clamp, a nozzle and a cutter. A second duct branches off from the first, close to its outlet into the weft feeder, which also comprises a nozzle, while the second device--positioned adjacent to the weft feeder drum, to receive the new yarn fed by the first device and by the winding arm and send it to a fixed point for feeding the main nozzle of the loom--comprises a curved profiled duct, which is either open or adapted to open longitudinally towards the drum and has an aerodynamic guide for the yarn.
Abstract: In a measuring weft feeder for fluid jet looms, comprising a weft yarn reserve winding unit with variable turn length of the weft yarn that length can be adjusted with a single operation. For this purpose, the winding unit comprises a drum of adjustable diameter, formed by associating a fixed eccentric cylinder with a plurality of movable rods, parallel to the axis of the cylinder and surrounding a wide portion of its periphery, the distance of the rods from the cylinder being variable and adjustable for each rod or for groups of rods. For each rod or group of rods, a control arm is provided slidable in a guide of the winding unit positioned perpendicularly to the axis of the unit, the arms being movable simultaneously in the respective guides under the control of a single operating member.
Abstract: An electromagnetic unit coacts with the winding drum of a weft feeding device to control unwinding of weft yarn from the drum. The electromagnetic unit comprises a movable stem surrounded by a pair of adjacent coaxial electromagnetic coils. Energization of one coil causes the stem to move into a position where it blocks unwinding of the yarn, whereas energization of the other coil retracts the stem and permits free unwinding of the yarn.
Abstract: Device to apply paraffin oil or like onto the surface of textile threads, so as to make them smoother and facilitate weaving thereof. The device includes: at least one container or vessel for a paraffin oil, closed by a cover; at least one rove or felt strip having at least one vertical length with the lower end plunged into the oil of the container and one length, usually horizontal, positioned beneath the cover of the container; and a distributing head, positioned beneath the cover of the container and above the path of the thread, and consisting of a filtering membrane, on the surface of which rests the rove, and of a member pressing the rove onto said membrane, the path of the thread being such that it laps from underneath the outer surface of said membrane.
Abstract: A device for greatly damping the oscillations and vibrations of weft yarns fed from a weft feeder to a loom, at the outlet of the feeder, particularly when yarn cutting takes place in the loom, comprises, in association with the conventional fixed yarn guide at the outlet of the weft feeder, a second fixed yarn guide, parallel to the first and downstream thereof, as well as an intermediate yarn guide, movable between a position in which it does not engage the weft yarn on its path between the two guides, and a position in which it engages the yarn and deviates it, forcing it to follow a winding path between the two guides. The positions of the intermediate yarn guide are controlled by an actuator and selected by the electronic circuit of the weft feeder, according to the working of the loom, so as to deviate the yarn when yarn cutting takes place.
Abstract: A device for detecting weft yarn breakage is adapted to be positioned upstream of a weft yarn feeding and storage device, and comprises a signal generator which directs the stoppage of the loom after a predetermined delay time T has elapsed from the moment at which weft yarn breakage is detected. The device comprises an electronic circuit including components which receive signals representative of the speed of the motor shaft and detection of weft yarn breakage. In one embodiment, the motor speed signal is fed to a counter-divider upon detection of weft yarn breakage, which in turn generates a signal after a time inversely proportional to the motor speed. This signal can be fed to a monostable circuit which generates the pulse for stopping the loom, the delay time T being in relation to the detected speed of the motor of the weft yarn feeding and storage device.
Abstract: A method and apparatus to adjust the motor speed in yarn feeders for textile machines and, in particular, weft feeders for weaving looms, wherein a yarn reserve is wound on a rotary drum held stationary, by a winding arm rotated by the motor. Photoelectric cells positioned close to a yarn outlet end of the drum emit signals which adjust--in cooperation with detection of the rotations of the winding arm--the motor speed of the feeder. These signals differ from each other according to whether an advancing turn of the yarn reserve intercepts a luminous beam for a relatively long period of time or whether yarn drawn from the reserve by the loom intercepts a luminous beam for a relatively short period of time. These signals are discriminated so as to adjust said speed, so as to guarantee the constant presence of an adequate yarn reserve on the drum.
Abstract: A casing for weft storage and feeding devices for use in weaving looms comprises a central body housing the motor; and a peripheral arm guiding and supporting the brake unit, the sensor detecting the yarn reserve, and the yarn-guide eyelet. The casing is formed from at least one extruded section length.
Abstract: A weft feeding device for weaving looms regulates the motor speed, according to the amount of yarn wound on the drum at least two photoelectric cells (11, 12) are provided one of which (11) checks the amount of yarn (3) wound on the drum (1), while the other (12) measures the transparency of the protection glass (15) provided on the cells. These photoelectric cells (11, 12) cooperate with an electronic circuit, which processes their signals (31, 32) in order to automatically compensate the transparency variations in the protection glass (15), thereby allowing a more uniform regulation of the motor speed of the weft feeding device.
Abstract: A rotor for weaving loom weft feeding devices, comprises a framework formed by a hub, a plurality of spokes extending outwardly from the hub at an oblique angle, and an outer circular rim. One of the spokes is larger than the others and contains the weft yarn passageway extending lengthwise thereof. Two thin covers enclose the framework and are fixed securely to it, which eliminates the build up of dust between the spokes. The rim defines annular recesses within which the motor casing on one side and the winding drum on the other side nest.
Abstract: Weft feeder for weaving looms, of the type wherein the drum (1) around which the weft yarn winds to form the reserve is held stationary, while the turns (3) of the reserve are laid thereon by a rotating reel (2) and are moved forward, mutually spaced, by a set of columns (5) prevented from rotating in respect of said drum (1), but partially and variably emerging from special seats of its periphery. The ensemble of columns has a frustoconical profile, each column (5) being tapered towards the feeder outlet end, until it no longer emerges from the seats where there is maximum tapering. A photoelectric cell unit (8), moving parallel to the axis of the drum (1), detects the presence and the consistency of the weft yarn reserve wound thereon, in order to control the rotation and regulate the speed of the motor of the feeder.
Abstract: In an improved electromagnet structure for stopping the unwinding of the weft yarn in weft feeding devices for weaving looms, comprises--mounted in a casing--an electromagnetic coil and an armature mobile therein. The armature comprises a shank, at least partly constituted by a piece of stainless steel cable and a head of ferrous material fixed to the shank by rolling and/or plastic deformation. The head is urged, on activation of the coil, to strike against a stopping plate interposed between the casing and its closure cover, against the action of a return spring and by way of a damping washer carried by the plate.
Abstract: In a weft feeder for weaving looms, a rotating arm winds a reserve of weft yarn turns around a drum held stationary and structure is provided to move forward the turns on the drum, keeping them mutually spaced. The structure comprises a set of columns, prevented from rotating in respect of said drum, but partially and variably emerging from seats in its periphery, thanks to the motion imparted thereto by the feeder motor shaft, in respect of which they are rotatably mounted by way of a skew bushing and a rotary bearing. This bushing is formed of two hollow bodies, the first of which is keyed to the motor shaft, eccentric in respect of the drum axis, while the second is rotatably mounted on the first, but adopted to be locked thereto in two positions at 180.degree. one in respect of the other and having its outer surface inclined in respect of that axis.