US3744093A

US3744093A - Method and apparatus for regularizing the output of drawing frames of the kind used in textile spinning

Info

Publication number: US3744093A
Application number: US00087874A
Authority: US
Inventors: E Felix
Original assignee: Zellweger Uster AG
Current assignee: Zellweger Uster AG
Priority date: 1969-12-09
Filing date: 1970-11-09
Publication date: 1973-07-10
Anticipated expiration: 1990-07-10
Also published as: NL7011398A; DE2031334C3; ES385514A1; DE2031334A1; GB1307023A; AT310047B; FR2068795B1; FR2068795A1; BE754038A; DE2031334B2; CH501740A; CA971326A

Abstract

Method and apparatus for regularizing the output of drawing frames of the type used in the textile spinning industry. At least one of the slivers delivered to the drawing frame is passed through a pair of cylinders having a rotational speed controlled by a measuring signal generated by a measuring element corresponding to the overall cross section of the output of the drawing frame.

Description

United States Patent 1 Felix [111 3,744,093 [451 July 10, 1973,

[ METHOD AND APPARATUS FOR REGULARIZING THE OUTPUT OF DRAWING FRAMES OF THE KIND USED IN TEXTILE SPINNING [75] Inventor: Ernst Felix, Uster, Switzerland [73] Assignee: Zellweger Ltd., Uster, Switzerland [22] Filed: Nov. 9, 1970 [21] Appl. No.: 87,874

' 301 Foreign Application Priority Data FOREIGN PATENTS OR APPLICATIONS 944,200 12/1963 Great Britain 19/240 Primary Examiner-Dorsey Newton A 110N10y-Cr211g and Antonelli 5 7 ABSTRACT Method and apparatus for regularizing the output of drawing frames of the type used in the textile spinning industry. At least one of the slivers delivered to the drawing frame is passed through a pair of cylinders having a rotational speed controlled by a measuring signal generated by a measuring element corresponding to the overall cross section of the output of the drawing frame.

9 Claims, 2 Drawing Figures PRESSURE l0 VOLTAGE m CONVERTER iiillilllmliliiiliflmliii/1"Till g- T llliiilllil 1 7 \"i 1 DRIVE I MEANS I i in: i 1 1 ii i i I PATENTED 1 0 5 3. 744.093

PRESSURE IO VOLTAGE A CONVERTER 1 -ATWNNAEINNN V 7 A DR'VE 6 I MEANS 1 A W A i i M N A A I W FIG. 2

2s V 2| DRIVE DRIVE MEANS 22 l g m MEANS A (A l I! )I BACKGROUND OF THE INVENTION The present invention relates to a method and apparatus for regularizing the output of drawing frames of the kind used in textile spinning.

Among other things, controlled sliver-drawing frames are being used to an ever increasing extent in the automation and qualitative improvement of the textile industry. They produce a more uniform sliver which is either equivalent to an improvement in quality or enables the production cycle to be shortened through a reduction in the number of passages required.

Regulated drawing frames are, however, expensive. In most cases, investment in them is only worthwhile in cases where a spinning mill is being equipped with new machinery. Existing drawing frames cannot be converted into regulated drawing frames usually for reasons of design.

SUMMARY OF THE INVENTION It is an aim of the present'invention to provide a method and apparatus to overcome the problems and disadvantages encountered heretofore.

The present invention provides a method of regularizing the output of drawing frames of the kind used in the spinning industry, wherein at least one of the slivers delivered to the drawing frames is passed through a pair of cylinders whose rotational speed is controlled by a measuring signal generated by a measuring element corresponding to the overall cross-section of the output of the drawing frame.

The present invention also provides an apparatus for regularizing the output of a textile drawing frame, comprising an actual drawing and drafting system as well as additional pair of cylinders having a drive which is controlled by a measuring element influenced by the output of the drawing frame with the additional rollers being arranged to subject at least one sliver to a variable draft in regard to its cross-section.

The present invention is based on the recognition that, for regularizing the output of drawing frames of the kind used in the spinning industry, a considerable textile-technological improvement is actually obtained simply by regulating out the prolonged fluctuations which are relatively low in amplitude. Accordingly, it is only fairly minor changes in draft, amounting to a few percent of the total draft, which are required to regulate them by modifying the draft. In this manner, it is possible to obtain the same effect by a correspondingly greater change in draft on only a proportion of the quantity of fibres passing through the drawing frame. For example, if in a drawing frame with six slivers arriving alongside one another only one of these slivers is subjected to an additional draft, it is still possible in theory to correct a fluctuation in the quantity of fibres of up to i 8 percent corresponding to i A. 1/6.

The foregoing affords the advantage that the outlay in terms of design required for driving and controlling one or only a few slivers remains moderate and can also be subsequently applied to already existing unregulated drawing frames. It is also possible to eliminate in this way the need to control sliver delivery because most of the fibres are delivered to the drawing frame at a constant rate. The drive system of, in particular, the latest double-headed high-performance drawing frames would have to be almost completely re-designed' because it is common to both outputs although as a' result of regulation the rates at which the slivers are delivered can no longer be the same. However, individual slivers as provided by the present invention can readily be drawn off directly from a can. Since, in addition, deviations from the required cross-section are generally very small in practice, it is sufficient-for only one or, two slivers to be regulated.

BRIEF DESCRIPTION OF THE DRAWING These and further objects, features and advantages of the present invention will become more apparent from the accompanying drawing which shows, for purposes of illustration only, several embodiments in accordance with the present invention and wherein:

FIG. 1 illustrates a drawing frame which is continuously regulated by an additional pair of cylinders as compared with known frames,

FIG. 2 illustrates another drawing frame regulated in stages by two additional pairs of cylinders.

DETAILED DESCRIPTION OF THE DRAWING Referring now to the drawing and, in particular, to FIG. 1, the

reference numerals

3, 4, 5 denote pairs of cylinders of a conventional multiple-cylinder drawing frame which, through suitably selected gear transmis sions, rotate at a constant speed and hence exert a constant draft on the slivers 9 which arrive from beneath. The output 2 is combined in a condenser l and deposited into cans in a known manner. A measuring element of the kind described in US. Pat. No. 3,435,673 is accommodated in the condenser l and generates a pressure measuring signal which is at least substantially proportional to the quantity of fibres passing through the condenser 1.

According to the present invention, an additional pair of cylinders 6 acts on the middle two slivers so that an additional drafting zone 7 is formed. This pair of cylinders 6 is driven by a variable speed motor arrangement 8, such as described in US. Pat. No. 3,l09,324. Adjustment of this rotational speed is controlled by the pressure measuring signal in such a way that an excessive quantity of fibres in the condenser 1 produces a reduction in the rotational speed, while a deficit of fibres in the condenser 1 produces an increase in rotational speed of the pair of cylinders 6. Conversion of the pressure measuring signal into the electrical signal or other quantity required to control the rotational speed of the variable-speed motor arrangement 8 is carried out by known techniques of control engineering, such as by a pressure voltage converter 10 of any conventional configuration.

This should accelerate or decelerate only relatively small rotating masses so that the performance and hence the dimensions of the control elements can be kept small. To ensure that these regulated slivers, which can be very thin, are also safely engaged in the web 2, it is advisable to deliver and regulate the slivers towards the middle rather than along the edges.

Instead of a continuous change in the rotational speed of the feed cylinders 6, it is also possible to use an intermittent system in cases where the demands, which the uniformity of output has to meet, are less stringent. In this case, regulation is of course limited to the delivery or non-delivery of a sliver. Since, as already mentioned, deviations from the required crosssection are relatively small, a single correction of this kind can be, sufficient in cases where the delivered sliver to be regulated is considerably thinner than the other slivers.

A considerable improvement in the uniformity of output is actually obtained simply by delivering two slivers much thinner than usual, rather than one, intermittently to the drawing frame, as diagrammatically illustrated in FIG. 2.

Reference numerals

30 and 31 are two fairly thin slivers. In order to obtain an idea of their size, they can each amount to three percent of the total cross-section of all the slivers and generally will fall within the range of 1 5 percent of the total quantity of fibers delivered to the drawing frame. In normal cases, one of the slivers, for example only the sliver 30, will arrive. It is delivered by way of the cylinder which in turn is driven by the motor or clutch 21. If the sliver is too thin, the cylinder 22 will also be rotated by the motor or clutch 23 so that the sliver 31 is also delivered. If the sliver is too thick, neither the band 30 nor the sliver31 will be delivered. In cases where for example the

sliver

30 or 31 makes up 3 percent of the overall cross-section, regulation will thus be accurate to 1.5 percent. However, the requirement is that the overall deviation should not be more than 4.5 percent. In practice, this requirement is often fulfilled, or can be produced again by way of an alarm circuit which allows manual intervention.

While I have shown and described several embodiments in accordance with the present invention, it is to be understood that the same is susceptible of numerous changes and modifications as will be apparent to one skilled in the art. I, therefore, do not wish to be limited to the details set forth herein but intend to cover all such changes and modifications as are encompassed by the scope of the present invention.

What is claimed is:

1. An apparatus for regularizing the output of a textile drawing frame, comprising means for drawing and drafting a plurality of individual slivers including at least one pair of main cylinders driven at a substantially constant speed, at least one pair of auxiliary cylinders having 'drive means connected thereto for controllably rotating said auxiliary cylinders, and a measuring element responding to the output of the drawing and drafting means for controlling said drive means, the pair of auxiliary cylinders being arranged to subject at least one sliver, but not all slivers, to a variable draft with respect to the cross-section thereof.

2. An apparatus according to claim 1, wherein the pair of auxillary cylinders is arranged in the middle of the drawing frame so as to act on at least a centrally arranged sliver of said plurality of individual slivers adjacent to one another for delivery to the drawing frame.

3. An apparatus according to claim 1, wherein said drive means includes means for continuously varying the rotational speed of the pair of auxiliary cylinders in dependence upon a measuring signal generated by the measuring element in response to the output of the drawing and drafting means.

4. An apparatus according to claim 3, wherein the pair of auxillary cylinders is arranged in the middle of the drawing frame so as to act on at least a centrally arranged-sliver of a group of individual slivers adjacent to one another for delivery to the drawing frame.

5. An apparatus according to claim 1, wherein two pairs of auxiliary cylinders are provided, each of which is arranged to receive a particular sliver, and said drive means includes means for controlling the rotational speed of the cylinders in such manner that, on the occurrence of a measuring signal corresponding to a total quantity of fibers within a predetermined tolerance range, only one of the pairs of auxiliary cylinders is driven at a predetermined rotational speed and the other pair of stopped, while both pairs of auxiliary cylinders are driven at a predetermined rotational speed when the measuring signal corresponds to a total quantity of fibers below the predetermined tolerance range, and both pairs of auxiliary cylindersare stopped when the measuring signal corresponds to a total quantity of fibers above the predetermined tolerance range.

6. A method of regularizing the output of a drawing frame including at least one pair of main drawing cylinders operating at a substantially constant speed for use in the spinning industry, comprising:

deliveringa plurality of slivers to said pair of main drawing cylinders of the drawing frame;

drafting said plurality of slivers at a substantially constant speed;

condensing said plurality of drafted slivers;

detecting the density variation of the cross-sectional output of the condensed sliver; and

changing the rate of feed of at least one, but not all,

of the slivers delivered to said main drawing cylinders in response to the detected density variations of the cross-sectional output of the condensed sliver. v

7. A method according to claim 6, wherein the step of changing the rate of feed of at least one, but not all, of the slivers includes selectively stopping at least two slivers, one sliver or none of the slivers in dependence upon whether the value of said density variation of the condensed sliver exceeds, is within or is less than a predetermined tolerance range, respectively.

8. A method according to claim 5, wherein the one sliver delivered at a changing rate has a fiber content per sliver of between about 1 percent and 5 percent of the total quantity of fibers delivered to the drawing frame.

9. A method according to claim 8, wherein said step of controlling the rotational speed includes regulating the speed within a predetermined tolerance range corresponding to the quantity of condensed fibers so as to regulate the speed in stages, whereby a constant quantity of fibers is added or retained when the density variation deviates from the tolerance range.

Claims

1. An apparatus for regularizing the output of a textile drawing frame, comprising means for drawing and drafting a plurality of individual slivers including at least one pair of main cylinders driven at a substantially constant speed, at least one pair of auxiliary cylinders having drive means connected thereto for controllably rotating said auxiliary cylinders, and a measuring element responding to the output of the drawing and drafting means for controlling said drive means, the pair of auxiliary cylinders being arranged to subject at least one sliver, but not all slivers, to a variable draft with respect to the crosssection thereof.

4. An apparatus according to claim 3, wherein the pair of auxillary cylinders is arranged in the middle of the drawing frame so as to act on at least a centrally arranged sliver of a group of individual slivers adjacent to one another for delivery to the drawing frame.

5. An apparatus according to claim 1, wherein two pairs of auxiliary cylinders are provided, each of which is arranged to receive a particular sliver, and said drive means includes means for controlling the rotational speed of the cylinders in such manner that, on the occurrence of a measuring signal corresponding to a total quantity of fibers within a predetermined tolerance range, only one of the pairs of auxiliary cylinders is driven at a predetermined rotational speed and the other pair of stopped, while both pairs of auxiliary cylinders are driven at a predetermined rotational speed when the measuring signal corresponds to a total quantity of fibers below the predetermined tolerance range, and both pairs of auxiliary cylinders are stopped when the measuring signal corresponds to a total quantity of fibers above the predetermined tolerance range.

6. A method of regularizing the output of a drawing frame including at least one pair of main drawing cylinders operating at a substantially constant speed for use in the spinning industry, comprising: delivering a plurality of slivers to said pair of main drawing cylinders of the drawing frame; drafting said plurality of slivers at a substantially constant speed; condensing said plurality of drafted slivers; detecting the density variation of the cross-sectional output of the condensed sliver; and changing the rate of feed of at least one, but not all, of the slivers delivered to said main drawing cylinders in response to the detected density variations of the cross-sectional output of the condensed sliver.