Textiles: fiber preparation – Working – Drafting
Reexamination Certificate
2000-08-21
2001-09-11
Calvert, John J. (Department: 3765)
Textiles: fiber preparation
Working
Drafting
C019S0650CR, C019S236000
Reexamination Certificate
active
06286188
ABSTRACT:
BACKGROUND
The present invention relates to a drafting system with a drive arrangement with a regulating device for regulating mass variations in a fibre mass supplied from a supply source to a drafting system in which arrangement the mass variations are detected by at least one measuring device coordinated to the drafting system and transmitted to a control unit.
In practice regulating drafting systems are known form the following publications:
JP-Gbm-5017/78 Nihon Keikzai KK
JP-A-155231/177 Nagoya Kinzoku Harinuno KK
DE-A-1931929 Zinser
DE-A-2230069 Texcontol
CH-B-599993 Graf
EP-C-354653 Hollingsworth
EP-A-544425 Hollingsworth
EP-A-604137 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.
A conventional card operates at a constant (pre-settable) production rate, i.e. the fibre sliver is delivered at a predetermined speed from the delivery arrangement The function of a regulating drafting system implies that the draft is variable (controllable). Provision of a large sliver storage device between the card delivery system must be variable. This, however, creates problems concerning the drive for 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 arrangement sliver storage device is arranged between the card and a regulating drafting system. This can be seen in particular in 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 preset desired values. The resulting deviation signal serves for controlling the drive motor for the intake pair of rolls of the drafting system in order to adapt the draft ration, and to level out thin and thick places respectively. At the same time, this signal transmitted to the control device for the drive of the fibre sliver source, or of the card 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, and in the material intake respectively, are leveled 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 determined by the sensors in the sliver storage device, the drives of the fibre sliver source (card) and of the fibre sliver take-up device (coiler) are changed accordingly in such a manner that the contents of the fibre 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 different inertia influences other that the elements of the sliver depositing device (coiler).
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 coordinated 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 in excess of a predetermined value in such a manner that the operation of the subsequent draw frame is not jeopardized. The arrangement shown is suitable for levelling out massive short term variation (loss of 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 is not envisaged in the arrangement described. The action in the control of the drive of the feed roll for compensating for long period mass deviations becomes effective, however, only after a major time delay.
The solutions proposed thus far generally provide the drafting system for levelling out short term variations in the fibre sliver. The correspondingly propose application of a measuring sensor at the intake of the drafting system.
Similar problems are encountered on other machines also, e.g. on the combing machine, if directly downstream from a textile processing unit a regulated drafting system is arranged which is driven at a regulated variable intake speed.
SUMMARY OF THE INVENTION
It thus is a goal of the present invention to proposed an apparatus which eliminates the problems described above in order to create a straightforward and functioning combination of a textile processing unit operating at essentially constant speed (supply source) with a subsequently arranged regulated drafting system unit. Additional objects and advantages of the invention will be set forth in the following description, or may be obvious from the description, or may be learned through practice of the invention. According to the invention, at least one further means is coordinated to the drafting system which is suitable to detect a regulating action on the drive of the drafting system required for maintaining a predetermined desired rotational speed before or during the regulating action and to apply it for influencing the base rotational speed of the drafting system.
Owing to this arrangement, the capacity of a storage device possibly required between the textile processing machine and the regulated drafting system arranged subsequently can be kept relatively small as the regulating actions are compensated for by adapting the base rotational speed of the drafting system. Furthermore, a security device is created which ensures that the drive rotational speed (base rotational speed) does not drift from a base setting.
The further means preferably is suitable to detect differences between the delivery speed of the supply source and the intake speed of the drafting system. The difference in speed results from the change in the rotational speed of the regulated roll of the drafting system.
The further means also can be suited for detecting long term mass variations relative to a pre-set desired value.
Preferentially, the further means is a fibre sliver storage device which can be equipped with corresponding sensor elements. Using said sensors, the differences in the transporting speed of the fibre sliver can be detected, which are caused by the variable and regulated take-off speed of the intake pair of rolls of the drafting system un it on the basis of the variable filing degree in the storage device, and the base rotational speed of the drafting system can be acted upon. Thus a pre-control is effected which ensures that the degree of filling of the storage device can be kept to a low level.
The
Faas Jurg
Gresser Theodore Götz
Grieshammer Christian
Muller Christian
Naf Beat
Calvert John J.
Dority & Manning
Maschinenfabrik Rieter AG
Welch Gary L.
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