Textiles: fiber preparation – Working – Drafting
Reexamination Certificate
2000-09-05
2003-06-24
Welch, Gary L (Department: 3765)
Textiles: fiber preparation
Working
Drafting
C019S240000
Reexamination Certificate
active
06581248
ABSTRACT:
The present invention concerns a regulating drafting system, in particular but not exclusively, for application at a card machine delivery arrangement. The present invention furthermore concerns a card with a first sensor for scanning the mass of the fibre material delivered by the card, in particular of the card sliver, the signal transmitted by the sensor being used for regulating the drive of the supply device of the card and preceded by a sliver storage device.
BACKGROUND
It is known that cards can be provided with regulating drafting systems in order to improve, or to ensure respectively, the evenness of the sliver delivered by the card. The following documents are cited merely as examples of the numerous publications representing the state of the art concerning this subject:
DE-A-1921248 Zellweger
DE-A-2912576 Zellweger
US-B-4075739 Rieter
EP-C-275471 Rieter
The solutions according to the sate of the art permit “maintaining of the sliver weight” (Long term regulation) as well as the elimination of the influence of variable lap layer thickness at the intake (short term disturbances).
Regulating drafting systems arranged at the card delivery are known from the following publications:
JP-Gbm-56017/78 Nihon Keikizai KK
JP-A-155231/77 Nagoya Kinzoku Harinuno KK
DE-A-1931929 Zinser
DE-A-2230069 Texcontrol
CH-B-599993 Graf
EP-C-354653 Hollingsworth
EP-A-544425 Hollingsworth
EP-A-6041137 Hollingsworth
EP-A-617149 Grossenheiner Textilmaschinenbau GmbH
EP-A-643160 Howa Machinery, Ltd.
EP-A-692560 Chemnitzer Spinnereimaschinenbau GmbH
US-B-5400476 Myrick-White, Inc.
The card operates at a constant (pre-settable) production speed; i.e. the fibre sliver is delivered at a pre-determined speed from the delivery arrangement. The function of a regulating drafting system implies that the draft be variable (controllable). Provision of a large sliver storage device between the card and the drafting system intake is undesirable. Thus the delivery speed of the drafting system must be variable. This, however, creates problems concerning the drive of the sliver deposition or coiler system, the inertia of which is relatively considerable, arranged downstream from the drafting system.
Various devices are known, e.g. from the DE-OS-19 19 929, in which a sliver storage device is arranged between the card and a regulating drafting system. This can be seen in particular from the
FIGS. 3 and 4
of the DE-OS reference. Adjoining the regulating drafting system, a sliver storage device is arranged driven by a separate motor. The measured values determined by the pair of measuring rolls upstream from the regulating drafting system are compared to the pre-set desired values. The resulting deviation signal serves for controlling the drive motor of the intake pair of rolls of the drafting system in order to adapt the draft ratio, and to level out thin and thick places respectively. At the same time, this signal is transmitted to the control device of the card, or of its main drum respectively, in such a manner that this drive also can be adapted correspondingly. The reaction of the card, however, is subject to substantially higher inertia than the drafting system. The resulting differences in the material delivery speed, and in the material intake speed respectively, are levelled out in the sliver storage device adjoining the card. The storage device in this arrangement is provided with sensors for scanning the contents of the storage device. Based on the contents scanned by the sensors in the sliver storage device, the drives of the fibre sliver source (card) and of the sliver take-up device (coiler) are charged correspondingly in such a manner that the contents of the sliver storage device is maintained substantially constant. This adaptation of the two drives however, results in additional differences, especially as the elements of the card (e.g. the card main drum) are subject to inertia influences differing from the ones in the elements of the sliver depositing device (coiler). Furthermore, in this case exact scanning of the sliver storage device contents must be provided.
Furthermore, from the previously published DE-A1-44 24 490 a co-ordination of cards is known in which a storage device is coordinated to each card downstream and in which the card slivers delivered by the individual storage devices after passing through a drafting system are delivered to a common sliver deposition device or coiler. In order to compensate for the loss of one of the card slivers supplied to the drafting system, the delivery speed of the drafting system is reduced until the missing card sliver has been re-inserted. In this arrangement a scanning sensor is co-ordinated to each individual card sliver. Owing to the reduction in delivery speed, corresponding to the loss of one card sliver, the fibre sliver reserve for the draw frame is exhausted more slowly than in the normal operating mode at higher intake speeds. In the example shown, an increase of the card delivery speed also is proposed if the fibre sliver storage device arranged downstream is depleted to below a pre-determined value in such a manner that the operation of the subsequent draw from is not jeopardized. The arrangement shown is suitable for levelling out massive short term variation (loss of a sliver). Levelling out long term deviations however, is not envisaged using this arrangement, or is solved unsatisfactorily only.
For levelling out long period mass deviations in the fibre sliver delivered by the card it is proposed in DE-A1 29 12 576 that the thickness of the fibre sliver delivered by the card be measured and compared to a pre-set desired value. The signal thus determined is used in controlling the material supply device (feed roll) arranged upstream from the card. Owing to this arrangement long period deviations in the mass of the card sliver delivered can be reacted on. Avoiding and eliminating of short wave deviations e.g. using a regulated drafting system arranged downstream is not envisaged in the arrangement described.
The solutions proposed thus far generally provide the drafting system for levelling out short term variations in the fibre sliver. They correspondingly propose of a measuring sensor at the intake of the drafting system.
SUMMARY OF THE PRESENT INVENTION
Objects and advantages of the present invention will be set forth in the following description, or may be obvious from the description, or may not be learned through practice of the invention.
The present invention in a first aspect provides a card with a regulating drafting system arranged at the card delivery. Measuring values are obtained from the drafted fibre sliver for regulating the drafting system (measuring point at the drafting system delivery). For this purpose the drafting bodies (i.e. the rotatable bodies driven at the higher speed for generating the draft) can be used as sensors. The term “bodies” in this context is understood to comprise such elements such as rolls, (discs), and cylinders.
The drafting bodies can be the delivery elements of the drafting system, in which arrangement the take-in bodies can be driven at a (constant) speed corresponding to the delivery speed of the fibre sliver leaving the card.
The take-in bodies can be coupled to the drive of the card delivery arrangement, or they can be driven under control synchronized with the card delivery arrangement. The take-in arrangement of the drafting system also can be provided with measuring elements, which permits a combination of the arrangement according to the state of the art.
The measuring values used for regulating the draft in the drafting system can be transmitted also to the card regulating device, e.g. for regulating the sliver weight on the card itself. The card preferentially also is equipped with a regulating system which can level out short term weight deviations in the lap fed in.
In cases in which the drafting system delivery speed is variable (for effecting controlled draft adaptations) the sliver deposition arrangement can be driven according to one of the known working principles or a
Faas Jürg
Müller Christian
Dority & Manning
Maschinenfabrik Rieter AG
Welch Gary L
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