Textiles: weaving – Weft manipulation – Weaving with stationary weft supply
Patent
1981-12-11
1983-10-18
Jaudon, Henry
Textiles: weaving
Weft manipulation
Weaving with stationary weft supply
D03D 4726
Patent
active
044100175
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a method for pneumatic insertion of the weft thread in the shuttle of a multifeed weaving loom, in which the weft thread, measured out in a predetermined length, is introduced by an air flow in an injector into the weft thread magazine of a shuttle traveling past the injector in continuous motion.
The invention furthermore relates to an apparatus for performing this method, which has an injector exposed to compressed air, to which the weft thread can be delivered from a thread measuring and delivery apparatus. The injector is disposed in the vicinity of the movement path of the shuttle of a multi-feed weaving loom in such a way that the weft thread can be introduced into the weft thread magazine of a shuttle passing the injector at that time.
BACKGROUND
In multi-feed weaving looms, a plurality of shuttles operate simultaneously, being moved while spaced apart from one another by the smallest possible distances. High weft-thread insertion performance is thus attained even at a relatively low shuttle speed. The short distances by which the shuttles follow one another necessitate a correspondingly short time sequence in supplying weft threads to the shuttles. In the case of shuttles operating with weft thread spools, a disproportionately great expense is required for constructing the shuttle supply means, which makes the utility of the entire multi-feed weaving loom uncertain.
In weaving looms with pneumatic insertion of the weft thread into the weft thread magazine of a particular shuttle (the magazine being embodied in the form of a chamber penetratable by air), it is possible with very simple technical means to attain a substantially better weft-thread insertion performance than would be the case if weft thread spools were used. The weft thread, measured out to a particular length, is then blown into the weft thread magazine by means of an injector through which a current of air flows. The length of the weft thread equals the width of the panel of fabric being woven, and the shuttle is supplied with a new weft thread between each two adjoining fabric panels.
The weft thread being introduced into the weft thread magazine of a shuttle is unwound from a cross wound spool or from a thread storage device located downstream of the spool. Ballooning of the thread then unavoidably occurs, being caused by the unwinding thread as it travels crosswise with respect to the direction in which thread is fed to the shuttle and thus intersects the air flow. Since air resistance increases with the square of the speed, the weft thread is subjected to severe strain, and its tear strength limits the speed with which it can be unwound.
In order to reduce the unwinding speed of the weft thread, it would be conceivable in principle to lengthen the weft thread magazine of an individual shuttle, in order to increase the length of time required for filling the weft thread magazine. However, this is not practicable,: since longer shuttles are then used, correspondingly fewer feed systems or shuttles can be accommodated in the weaving loom, so that the loom output would drop.
The invention:
It is accordingly an object of the invention to provide a method and apparatus for rapid supply of thread to the shuttles of a multi-feed weaving loom by pneumatic means, within a short distance shuttle movement path and with the correct weft thread for the intended fabric panel width, without thereby necessitating excessive strain on the weft thread or an extension in length of the weft thread magazine of the shuttles.
In accordance with, the invention, the injector, beginning at an outset position, is carried along with the shuttle at a slower speed for a predetermined distance while the weft thread is being introduced into the weft thread magazine. At the end of this distance the injector is rapidly brought back into its outset position.
There is a certain distance between the individual shuttles because of the shuttle stop and the changing of the shed. Because the injector is carried along with the shuttle while the
REFERENCES:
patent: 3319663 (1967-05-01), Fend
patent: 3943976 (1976-03-01), Vilaseca
patent: 4132248 (1979-01-01), Steiner
patent: 4253498 (1981-03-01), Luchi
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