Textiles: weaving – Stopping – Weft
Patent
1997-03-05
1998-10-27
Falik, Andy
Textiles: weaving
Stopping
Weft
139459, 242912, 226 11, 112273, 66161, D03D 5134, D03D 3700
Patent
active
058266267
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a device for monitoring wefts in a circular loom which are wound off from the respective bobbin of the weaving shuttles rotating in the weaving shed along a circular path formed by the circular reed and are delivered to the fabric edge of the woven hose, whereby a scanning means monitors the respective weft in order to generate an electric control signal in case of a weft fault.
2. Description of Prior Art
Circular looms are generally known in which a plurality of sectional shafts are arranged in a circular way around the circular reed of the machine and each carry a plurality of inner and outer harnesses for guiding a part of the two circularly distributed warp assemblages which are subjected to an opposing upwardly and downwardly alternate movement for forming the weaving or walking shed via a rotating main shaft. The weaving shuttles rotatingly driven by the main shaft in the circular reed deliver the weft to be drawn off from the respectively entrained bobbin continuously to the walking shed. The woven hose thus produced is then drawn off and wound up as a flat circular fabric.
In this respect it is essential that the proper presence of the wefts to be drawn off from the bobbins of the rotating shuttles is monitored as carefully as possible in order to control the machine in a respective way for preventing weaving faults, e.g. by turning it off immediately in case of weft faults which may be caused by breakage of the weft or exhaustion of the weft bobbin.
Known devices of this kind use, among other things, photooptical sensing elements in which the photocell is activated by a reflecting surface pivoting into the light beam. Such light barriers, however, can no longer meet current requirements, particularly in view of the considerably increased revolving speeds of the weaving shuttles and the generation of precise control signals.
Light barriers have always been susceptible to influences by external light, become easily dusty and do not allow any processing of reflex ribbons owing to "blinding".
SUMMARY OF THE INVENTION
It is thus the object of the present invention to provide a device for monitoring the wefts in a circular loom which is not subject to the disadvantages of the known state of the art.
This is achieved at first in accordance with the invention in that the electric control signal is producable by a magnetic sensor which is arranged in the zone of the revolving path of the weaving shuttles and which cooperates with a permanent magnet carried by the respective weaving shuttle, whereby the permanent magnet is arranged on a pivoting lever deflected by the drawn-off weft against the effect of spring-like return means and is held outside of the operative connection with the magnetic sensor in order to reach, in case of a weft fault, under the influence of the return means its end position producing an operative connection of the permanent magnet with the magnetic sensor for generating an active control signal.
Such a device is neither subject to any influence by external light, nor to any malfunctions through dust accumulation or to any wear and tear. This device, however, allows the processing of reflex ribbons, works securely at any revolving speed of the shuttles and is provided with a very high response sensitivity and response speed.
In order to reduce the revolving path of the affected shuttle with its permanent magnet to the magnetic sensor to a few angular degrees it is advantageous to arrange on the reed or the like a plurality of such magnetic sensors distributed over the circumferential direction.
A simple and functionally entirely secure arrangement can be achieved furthermore in that the pivoting lever carrying the permanent magnet at its free end is arranged with its pivoting axle on the thread insertion apparatus of the shuttle and is under the influence of a return spring, whereby the drawn-off weft penetrates or at least partly wraps around an end section at the free end of the pivoting le
REFERENCES:
patent: 2711759 (1955-06-01), Low et al.
patent: 4234021 (1980-11-01), Clokie
patent: 4361172 (1982-11-01), Tori
patent: 4422402 (1983-12-01), Ogihara
patent: 4616681 (1986-10-01), Huemmer
Falik Andy
Starlinger & Co. Gesellschaft mbH
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