A device for automatic removal of mispicked weft on weaving machines

Abstract: The invention refers to a device for automatic removal of mispicked weft on weaving machines ensuring that the mis­ picked weft is removed reliably. In principle, it consists of a hook (2) fixed to a shaft and equipped with a holding nozzle (6), of a stationary drive disc (7), and of an axially sliding driven disc (8). The holding nozzle is made as an outlet of a tube fixed to the hook and connected to a source (5) of pressurized air. The shaft (3) to which is fixed the hook is connected with a servomotor (11). The drive disc and the driven disc are situated in front of the hook, and the whole device is seated on a base plate (1) over the woven fabric.

Description: The invention relates to a device for gripping and removing a mispicked weft in a weaving machine subsequent to its cutting and releasing from the beat-up line. A known device for removal of mispicked weft comprises a rotary stripping brush for releasing the mispicked weft from the beat-up line and for feeding it by air jets into a pick channel in which the feed weft is either sucked off or blown away. The drawback of this device consists in that the removal course of the weft is not always fully reliable. Other known devices for releasing and drawing off a mispicked length of an uncut weft are disclosed in EP-A3-100 939. One of said devices comprises a mispicked weft release hook adapted to move between the weft gripping position in the shed and its initial outer position. The hook is separately pivotably mounted on the free end of a swing arm mechanism comprising two other rotary elements so that the correct adjustment of the whole system and of the hook into the required position in the shed is very difficult and the release of a mispicked weft from the shed is not reliable. A suction nozzle is located inside the hook and intended to drawing off by suction the weft released by the hook. Due to the forces between the weft and the warp, even this arrangement is not reliable. EP-A3-100 939 also discloses another device for removing a mispicked weft from the shed, equipped with two driven rollers, and a weft suction channel situated behind said rollers. This device is situated next to the warp, near the weft pick site and can draw out only a weft which has not yet been cut. The weft is gripped between the circumferential surfaces of the rollers and drawn out. Even this device is not quite reliable when the roller circumferential surfaces are worn out or soiled. The object of the invention is to overcome the drawbacks of the prior art and to propose a device for automatic removal of mispicked weft, which is reliable in its function and simple in its construction. This object will be solved according to the invention by the features of claim 1. The principle of the device according to this invention consists in that the weft gripping hook is combined with the holding nozzle for blowing an air jet into the weft gripping hook and that the weft drawn out by a swing motion of the gripping hook will be clamped between the inner front surfaces of the driving disc and of the axially shifted driven disc. Preferably, the gripping hook is fixed on a pivot arm connected to a rotary shaft and swingably driven by a servomotor. The advantages of the device according to the invention consist first of all in that the released weft is reliably gripped by the hook due to the action of the holding jet, and also reliably fed between the driving and the driven disc so that the whole weft removal procedure is carried out reliably. The device according to the invention permits to remove any number of wefts on any weaving machine type without cutting down its operation speed. An example of the device according to the invention will be described in detail with reference to the accompanying drawings, wherein Fig. 1 is a schematic perspective view of the device according to the invention at the beginning of the mispicked weft removal action, Fig. 2 is a schematic perspective view of the device according to the invention in the subsequent stage of the mispicked weft removal action, and Fig. 3 is a schematic perspective view of the device according to the invention with the hook returned to its initial position. The device according to the invention is seated on a base plate 1 situated over the woven fabric on a not shown holder of an inlet temple of the weaving machine. The device comprises a hook 2 fixed on the end of a pivot arm 12 connected to a shaft 3 driven by a servomotor 11. Attached to the body of the hook 2 is a tube 4 coupled with a supply line 5 of pressurized air. The outlet of the tube 4 is made as a holding nozzle 6 of the hook 2. On the base plate 1 is mounted for rotation a drive disc 7 connected with a not represented electric motor, and a driven disc 8, axially slidable for instance by means of a not represented bellows. The first stage of the separation cycle consists in that the machine (weaving machine) is stopped due to a signal of a sensor of a not represented weft stop motion. This either prevents the following weft from being picked or, if the pick of the not represented following weft does take place, this picked following weft is removed, for instance by being blown out of the shed by means of a known, not represented nozzle blowing air transversely to the pick axis. The beaten-up and cut off weft 9 is then released, for instance by the reverse motion of the shafts, and removed from the beat-up line, for instance by means of a not represented rotary brush. The hook 2 is then by means of a servomotor 11 (Fig. 1) turned to its operative position in a shed 10, and the released weft 9 is fixed by means of the pressurized air flowing out of the holding nozzle 6. By the reverse turning motion of the hook 2, the weft 9 is drawn out between the shed 10 threads in the shape of a loop (Fig. 2). The holding nozzle 6 still reliably holds the weft 9 on the hook 2. When the hook 2 is returned to its initial position (Fig. 3), the weft 9 is tensioned between the drive disc 7 and the driven disc 8. The drive disc 7, connected with a not represented electric motor, begins to rotate, and the driven disc 8 is by means of a not represented mechanism, for instance by air bellows, pressed to the drive belt 7. In this way, the weft 9 is gripped between the driven disc 8 and the drive disc 7, and by means of this drawn off the shed 10. The whole operation cycle can be repeated a number of times.

Claims: Device for gripping and removing a mispicked weft in a weaving machine, comprising: a gripping hook swingably mounted on a support member of the machine and swingably driven between an initial outer position and a gripping position, means for drawing off the gripped weft, characterized in that an air blowing nozzle (6) is mounted on the gripping hook (2) for blowing an air jet against the holding end of said hook (2), and the drawing-off means for the gripped cut weft (9) are designed as a rotatable driving disc (7) and an axially shiftable driven disc (8), said discs (7, 8) are disposed in such a way that the gripped weft (9) drawn out by a pivot motion of the hook (2) passes between the inner front faces of said discs (7, 8) and is clamped therebetween. Device according to claim 1, characterized in that the gripping hook (2) is fixed on a pivot arm (12) connected to a rotary shaft (3) and driven by a servomotor (11). Device according to claim 1 or 2, characterized in that the rotary shaft (3) and the two discs (7, 8) are mounted in parallel on a base plate (1) disposed over the woven fabric.

Inventors: VELECHOVSKY PETR, VELECHOVSKY, PETR
Applicants: ELITEX ZAVODY TEXTILNIHO, ELITEX KONCERN TEXTILNIHO STROJIRENSTVI
Application year: 1990
Main classification: D03D51
IPC codes: D03D51, D03D49